Research activity information

• Preliminary longitudinal epigenetic clock analyses of patients with mild cognitive impairment through nutritional intervention.

  Kiriko Minami, Toshiyuki Shirai, Satoshi Okazaki, Shohei Okada, Masao Miyachi, Ikuo Otsuka, Akitoyo Hishimoto

  BackgroundMild cognitive impairment (MCI) is an intermediate stage between normal aging and dementia. Not a small number of patients with MCI progress to Alzheimer's disease within 1 year. Epigenetic changes in DNA methylation, such as those observed in the epigenetic clock, are receiving increasing attention in the field of aging research. It is crucial to demonstrate the effectiveness of interventions for patients with MCI from a biological perspective to promote the prevention of dementia.ObjectiveWe conducted epigenetic clock analysis, mainly longitudinal evaluation, on patients with MCI who received intervention with vitamin D and/or marine omega-3 fatty acid supplements.MethodsWe conducted epigenetic clock analyses with public DNA methylation datasets from the Gene Expression Omnibus database. This dataset contains two timepoints' longitudinal DNA methylation data of 25 patients with MCI and 20 controls. They received two-year intervention with vitamin D and/or marine omega-3 fatty acid supplements. We conducted comparative analyses with Wilcoxon signed-rank test, and regression analyses of three models.ResultsIn patients with MCI, PhenoAge and GrimAge significantly decelerated after the intervention in comparative analyses. These clocks nominally significantly decelerated also in most of regression analyses. Moreover, natural killer cells showed significant differences before and after the intervention.ConclusionsWe found deceleration of some epigenetic clocks in patients with MCI with interventions. We believe that it is crucial to conduct additional epigenetic clock analyses in cohorts with larger sample sizes or in cohorts with interventions such as occupational therapy and pharmacotherapy are actively conducted.

  Jul. 2025, Journal of Alzheimer's disease : JAD, 13872877251360230 - 13872877251360230, English, International magazine

  Scientific journal


• Unraveling time-dependent genetic components underlying alcohol response.

  Hikino K, Otsuka I, Oshima S, Hishimoto A, Ozaki K, Liu X, Ishikawa Y, Mushiroda T, Matsushita S, Terao C.

  While numerous studies have examined the subjective response to alcohol as an intermediate phenotype to understand its variability, heritability, and predictive capacity for alcohol-related disorders, in-depth analyses linking alcohol reactivity indicators to genetic factors within a large cohort have been absent. Our study aimed to quantify the exact contribution of each genetic variant relevant to the alcohol metabolism to the variability in alcohol response. Specifically, we focused on two primary genes involved in alcohol metabolism (ALDH2 and ADH1B) and three additional loci (ALDH1B1, ALDH1A1, and GCKR) that have been shown to have significant associations with drinking behaviors in Japanese individuals. We conducted the first study to assess the relationship between subjective response to alcohol (SR), evaluated by various assessment subscales, and genetic factors using an intravenous clamp technique in 429 healthy Japanese young adults. By reducing the dimensionality of the data to assess similarity structures, we identified three distinct clusters of SRs and participants. Each participant cluster exhibited a distinct alcohol response profile shaped by specific genetic contributions. Participant cluster 1 demonstrated the strongest response, followed by participant cluster 2, and then participant cluster 3. Participant cluster 1 may also be the most strongly influenced by the allelic status of ALDH2 and ADH1B. SR patterns varied accordingly, and the enrichment of the ALDH2*2 and ADH1B*2, differed across both participant and subscale clusters. Notably, the three participant clusters closely aligned with the three subscale clusters, highlighting a consistent genotype-phenotype relationship. Furthermore, the proportion of variance explained by these genes also varied across subscale clusters. Contrary to known functions, ADH1B showed associations at later timings when ALDH2 associations attenuate. Our three-cluster classification may improve prevention by enabling early identification of individuals at health risk.

  Jun. 2025, Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, English, International magazine

  [Refereed]

  Scientific journal


• Increased somatic mosaicism in autosomal and X chromosomes for suicide death.

  Otsuka I, Uchiyama S, Shirai T, Liu X, Takahashi M, Kamatani Y, Terao C, Hishimoto A.

  Mosaic chromosomal alterations (mCAs) are classified as mosaic deletions (loss), copy-neutral loss of heterozygosity (CN-LOH), and duplications (gain), attracting special attention as biological aging-related acquired genetic alterations. While these mCAs have been linked with aging and various diseases, no study has investigated their association with suicide risk which is associated with abnormal biological aging. Here, we examined the association between suicide deaths and mCAs, including mosaic loss of the X (mLOX) and Y chromosomes, by leveraging blood-derived single nucleotide polymorphism-array data. The first (410 suicide decedents and 88,870 controls) and the second (363 suicide decedents and 88,870 controls) cohorts were analyzed and integrated using meta-analyses (773 suicide decedents and 177,740 controls). Total mCAs in autosomal chromosomes were significantly increased in suicide (p = 1.28 × 10-6, odds ratio [OR] = 1.78), mostly driven by loss (p = 4.05 × 10-9, OR = 2.70) and gain (p = 1.08 × 10-3, OR = 2.23). mLOX were significantly increased in female suicide (p = 2.66 × 10-21, OR = 4.00). The directions of effects of all mCAs in autosomal and sex chromosomes on suicide were the same in the first and second sets. Subgroup analyses suggest that our findings were mostly driven by suicide itself, and not confounded by comorbid psychiatric disorders or physical diseases, smoking status, sample location, or postmortem sample status. In conclusion, we provide the first evidence for aberrant mCAs in somatic autosomal and X chromosomes in suicide, which may contribute to an improved understanding of the genomic pathophysiology underlying suicide.

  Lead, Mar. 2025, Molecular Psychiatry, 30(3) (3), 881 - 888, English, International magazine

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Epigenetic Clock Analysis for National Institutes of Health Stroke Scale in Patients With Ischemic Stroke.

  Wenshan Jiang, Toshiyuki Shirai, Ikuo Otsuka, Satoshi Okazaki, Takaki Tanifuji, Tadasu Horai, Haruka Minami, Masao Miyachi, Shohei Okada, Akitoyo Hishimoto

  AIM: Strokes are the second most common cause of mortality and disability worldwide. Ischemic strokes account for the main part of strokes. Recently, the epigenetic changes that occur during biological aging through DNA methylation have gained attention. The National Institutes of Health Stroke Scale (NIHSS) scores measure physical and cognitive function. We hypothesized that there are associations between acute changes in the NIHSS score and biological aging in patients with ischemic stroke. We conducted epigenetic clock analyses to investigate the association between the difference in NIHSS (dNIHSS) and epigenetic clock in patients with ischemic stroke. METHODS: We used two publicly available DNA methylation data sets from Caucasian patients with ischemic stroke in Spain. The discovery data set consists of 59 patients with ischemic stroke, and the replication dataset consists of 62. Acceleration of several epigenetic clocks (HorvathAge, HannumAge, SkinBloodAge, PhenoAge, GrimAge, GrimAge2, DNA methylation-based telomere length, and DunedinPACE), GrimAge components, and GrimAge2 components was analyzed with standard multiple regression analyses with dNIHSS. We obtained information on dNIHSS between discharge and baseline for each patient. We integrated these results from the two data sets using meta-analyses. RESULTS: There was no significant association in the epigenetic age acceleration. The predictive value of only Cystatin C showed a significant association with dNIHSS in the GrimAge components. CONCLUSIONS: We could not find a significant association between the severity during the acute phase of ischemic stroke and epigenetic clocks. We may be able to find different findings with a larger sample size and longitudinal data such as NIHSS scores at fixed intervals.

  Mar. 2025, Neuropsychopharmacology reports, 45(1) (1), e70009, English, International magazine

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Relationship of Major Depressive Disorder and Schizophrenia Polygenic Risk Scores to Suicide: A Comparison Between European and Asian Ancestry Populations.

  Otsuka I, Galfalvy H, Guo J, Akiyama M, Okazaki S, Terao C, Rujescu D, Turecki G, Hishimoto A, Mann JJ.

  Psychiatric diagnosis rates in suicide decedents appear higher in European ancestry populations compared with East Asians. Shared genetic components exist between major depressive disorder (MDD)/schizophrenia (SCZ) and suicide, but no study has compared these shared polygenic architectures between Europeans and East Asians. We compared polygenic risk scores (PRSs) for MDD/SCZ determined from large data sets specific to each ancestry in European and East Asian suicide decedent samples. MDD/SCZ PRSs appeared more prominent in European suicides compared with Japanese suicides. A greater coexistence of psychiatric disorders in European suicide decedents than in East Asian suicide decedents may be partly explained by genetics. Our results are limited by the smaller sample size of our suicide decedents and sample size disparities between the European discovery data set and the East Asian data set for MDD/SCZ, resulting in less statistical power to detect robust difference between the two ancestries.

  Lead, 2025, Archives of Suicide Research : official journal of the International Academy for Suicide Research, 29(1) (1), 309 - 316, English, International magazine

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Preliminary development of a risk predictor for severe complication in patients with anorexia nervosa.

  Toshiyuki Shirai, Takaki Tanifuji, Ikuo Otsuka, Satoshi Okazaki, Tadasu Horai, Naruhisa Yamaki, Haruka Minami, Masao Miyachi, Shohei Okada, Akitoyo Hishimoto

  Anorexia nervosa (AN) is life-threatening because of many physical complications, hence a quantitative indicator for early therapeutic intervention through hospitalization is needed. Here, we compared the demographics of 21 patients with AN who required intensive treatment in the internal medicine ward and those of 61 patients with AN who directly admitted to the psychiatric ward. We developed a risk score for severe physical complications in patients with AN, by using six items with significant differences between two groups; body mass index, blood urea nitrogen, corrected calcium, albumin, aspartate transaminase, and C-reactive protein (area under the curve = 0.824).

  Dec. 2024, Psychiatry research, 342, 116151 - 116151, English, International magazine

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Biological aging analysis based on DNA methylation status for social anxiety disorder.

  Nobuhiko Noguchi, Toshiyuki Shirai, Akira Suda, Saki Hattori, Masatoshi Miyauchi, Satoshi Okazaki, Junichi Fujita, Takeshi Asami, Ikuo Otsuka, Akitoyo Hishimoto

  AIM: Social anxiety disorder (SAD) is a common disorder characterized by excessive fear of scrutiny and embarrassment, leading to severe distress and avoidance behaviors or dysfunctions. SAD and other relevant diseases have been reported to be associated with a higher risk of aging-related diseases, such as Alzheimer's disease, Parkinson's disease, and diabetes mellitus. Recently, epigenetic clock analysis, which measures biological aging based on comprehensive DNA methylation (DNAm) status, has been widely conducted. We conducted epigenetic clock analyses in patients with SAD and controls, examining various epigenetic age acceleration and DNAm-based predictive values of aging-related proteins (GrimAge components and GrimAge2 components), including leptin level. METHODS: We used the publicly available DNAm dataset, GSE164056, which consists of 66 patients with SAD and 77 controls of Caucasian descent aged between 18 and 50 years. We conducted regression analyses investigating the association between SAD and various indices of epigenetic aging, using age and sex as covariates. RESULTS: None of the epigenetic clocks showed significant differences in age acceleration. Of the DNAm-based predictive values of aging-related proteins, leptin level in GrimAge components (q = 0.0123) and GrimAge2 components (q = 0.0123) were significantly lower in patients with SAD than in controls. CONCLUSIONS: The results of this study suggested that leptin may be involved in SAD pathogenesis as an aging-related protein. Therefore, further studies with different designs are required.

  Dec. 2024, Neuropsychopharmacology reports, 44(4) (4), 774 - 783, English, International magazine

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Meta-analyses of epigenetic age acceleration and GrimAge components of schizophrenia or first-episode psychosis.

  Toshiyuki Shirai, Satoshi Okazaki, Takaki Tanifuji, Shusuke Numata, Tomohiko Nakayama, Tomohiro Yoshida, Kentaro Mouri, Ikuo Otsuka, Noboru Hiroi, Akitoyo Hishimoto

  Schizophrenia is a common chronic psychiatric disorder that causes age-related dysfunction. The life expectancy in patients with schizophrenia is ≥10 years shorter than that in the general population because of the higher risk of other diseases, such as cardiovascular diseases. Aging studies based on DNA methylation status have received considerable attention. Several epigenetic age accelerations and predicted values of aging-related proteins (GrimAge and GrimAge2 components) have been analyzed in multiple diseases. However, no studies have investigated up to GrimAge and GrimAge2 components between patients with schizophrenia and controls. Therefore, we aimed to conduct multiple regression analyses to investigate the association between schizophrenia and epigenetic age accelerations and GrimAge and GrimAge2 components in seven cohorts. Furthermore, we included patients with first-episode psychosis whose illness duration was often shorter than schizophrenia in our analysis. We integrated these results with meta-analyses, noting the acceleration of GrimAge, GrimAge2, and DunedinPACE, and increase in adrenomedullin, beta-2 microglobulin, cystatin C, and plasminogen activation inhibitor-1 levels, in patients with schizophrenia or first-episode psychosis. These results corroborated the finding that patients with schizophrenia had an increased risk of diabetes, cardiovascular disease, and cognitive dysfunction from a biological perspective. Patients with schizophrenia and first-episode psychosis showed differences in the results when compared with controls. Such analyses may lead to the development of novel therapeutic targets to patients with schizophrenia or relevant diseases from the perspective of aging in the future.

  Nov. 2024, Schizophrenia (Heidelberg, Germany), 10(1) (1), 108 - 108, English, International magazine

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Pharmacokinetics of Brexpiprazole, Quetiapine, Risperidone, and Its Active Metabolite Paliperidone in a Postpartum Woman and Her Baby.

  Toru Konishi, Yumi Kitahiro, Naoko Fujiwara, Kazuhiro Yamamoto, Mari Hashimoto, Takahiro Ito, Kotaro Itohara, Kazumichi Fujioka, Hitomi Imafuku, Ikuo Otsuka, Tomohiro Omura, Ikuko Yano

  BACKGROUND: Brexpiprazole is a second-generation antipsychotic approved in Japan in 2018; however, information on placental passage and breast milk transfer remains limited. In this report, the patient, a 30-year-old pregnant woman with schizophrenia, was medicated with brexpiprazole, risperidone, and quetiapine. METHODS: The study used high-performance liquid chromatography-tandem mass spectrometry to determine the concentrations of brexpiprazole, quetiapine, risperidone, and its active metabolite (paliperidone) in maternal and neonatal plasma, cord venous plasma, and breast milk. Maternal plasma samples were obtained approximately 2 and 8 hours after the last administration of antipsychotics on the day of delivery and at the estimated drugs' trough time on days 1, 3, and 5 after delivery. RESULTS: The maternal plasma concentrations of brexpiprazole, quetiapine, and paliperidone increased by approximately 3.5-fold on the fifth day compared with those on the day of delivery, whereas the risperidone concentration remained almost constant. Moreover, the neonatal plasma concentrations of the 4 drugs immediately after birth were indistinguishable from the umbilical cord concentrations and gradually decreased, except for risperidone. Relative infant doses of these compounds were below 1.1%. CONCLUSIONS: Pregnancy status notably alters the pharmacokinetic properties of antipsychotics. Therefore, close and careful monitoring of clinical symptoms should be considered during pregnancy and after delivery. Although brexpiprazole is transferred to neonates through the placenta, breastfeeding is still possible because the relative infant dose value of this drug was much less than 10%.

  Oct. 2024, Therapeutic drug monitoring, 46(5) (5), 687 - 691, English, International magazine

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Comprehensive analysis including in-game spending and violent game playing in patients with internet gaming disorder.

  Haruka Minami, Toshiyuki Shirai, Shohei Okada, Masao Miyachi, Takaki Tanifuji, Satoshi Okazaki, Tadasu Horai, Kentaro Mouri, Ikuo Otsuka, Akitoyo Hishimoto

  AIM: Internet gaming disorder (IGD) is receiving increasing attention. In particular, violent gameplay or in-game spending affects the psychiatric conditions and economic difficulties of patients. We conducted regression analysis and path analysis to investigate the associations between a comprehensive list of factors in patients with IGD, including the degree of internet or gaming dependence, developmental problems, family background, severity of depression, sleeping habits, in-game spending, and first-person shooter (FPS) and third-person shooter (TPS) game playing. METHODS: The participants were 47 Japanese individuals (39 males and 8 females) aged ≤20 years diagnosed with IGD with complete data from the internet addiction test, autism spectrum quotient, Quick Inventory of Depressive Symptomatology, and Pittsburgh Sleep Quality Index. All participants were asked whether their parents have divorce history, whether they have siblings, whether they play FPS or TPS games, and whether they engage in in-game spending. Firstly, we compared these factors between males and females; secondly, we conducted regression analysis and path analysis in male patients. RESULTS: As for simple comparison between sex, female patients showed greater severity of IGD and depressive score. In regression analysis of male patients, significant associations were found between FPS or TPS game playing and in-game spending. We also created path diagrams. CONCLUSION: The results of the comprehensive analyses suggest the possibility that bidirectional synergistic effects could be achieved by gradually reducing both violent game playing and in-game spending. The concept of internet dependence has a wide range of meanings, and for each subtype, it is important to consider the background that led to the dependence to make individualized environmental adjustments and provide psychotherapy.

  Sep. 2024, Neuropsychopharmacology reports, 44(3) (3), 631 - 638, English, International magazine

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Accelerated epigenetic aging in alcohol dependence.

  Toshiyuki Shirai, Satoshi Okazaki, Ikuo Otsuka, Masao Miyachi, Takaki Tanifuji, Ryota Shindo, Shohei Okada, Haruka Minami, Tadasu Horai, Kentaro Mouri, Akitoyo Hishimoto

  Alcohol dependence poses a global health threat associated with aging and reduced life expectancy. Recently, aging research through deoxyribonucleic acid (DNA) methylation has gained attention. New epigenetic clocks have been developed; however, no study has investigated GrimAge components, GrimAge2 components and DunedinPACE in patients with alcohol dependence. In this study, we aimed to perform epigenetic clock analysis to evaluate epigenetic age acceleration and DNA methylation-based age-predictive components in patients with alcohol dependence and controls. We utilized publicly available DNA methylation data (GSE98876) for our analysis. Additionally, we compared the values of the same items before and after the patients underwent a treatment program. The dataset comprised 23 controls and 24 patients. We observed that DunedinPACE accelerated more in patients with alcohol dependence. AgeAccelGrim and AgeAccelGrim2 decelerated more after the treatment program than before, and beta-2-microglobulin and Cystatin C decreased after the treatment program than before. These findings are crucial as they affect the cranial nerve area, potentially contributing to cognitive dysfunction and psychiatric symptoms in patients with alcohol dependence.

  May 2024, Journal of psychiatric research, 173, 175 - 182, English, International magazine

  Scientific journal


• Association study of a single nucleotide polymorphism in the hypoxia response element of the macrophage migration inhibitory factor gene promoter with suicide completers in the Japanese population.

  Toshiyuki Shirai, Satoshi Okazaki, Takaki Tanifuji, Ikuo Otsuka, Masao Miyachi, Shohei Okada, Ryota Shindo, Tadasu Horai, Kentaro Mouri, Motonori Takahashi, Takeshi Kondo, Yasuhiro Ueno, Akitoyo Hishimoto

  BACKGROUND: More than 800 000 people die by suicide annually. The heritability of suicide is 30%-50%. We focused on the hypoxia response element (HRE), which promotes the expression of macrophage migration inhibitory factor (MIF) via the hypoxia-inducible factor (HIF) pathway, important in neurogenesis and neuroprotection. We examined a genetic polymorphism of rs17004038, a single-nucleotide polymorphism (SNP), in suicide completers and controls. METHODS: The study population included 1336 suicide completers and 814 unrelated healthy controls. All participants were Japanese. We obtained peripheral blood, extracted DNA, and genotyped the patients for SNP rs17004038 (C > A). RESULTS: No significant differences were observed between the two groups in either the allele or genotype analyses. Subgroup analyses by sex, age (<40 or ≥40), and suicide method (violent or nonviolent suicide) were performed with similar results. CONCLUSION: No association was observed between SNP rs17004038 and suicide completion. Although it is challenging to collect a large number of samples from suicide completers, further MIF-related genetic studies, including those of rs17004038, are necessary with larger sample sizes.

  Mar. 2024, Neuropsychopharmacology reports, 44(1) (1), 262 - 266, English, International magazine

  Scientific journal


• Epigenome-wide association study on methamphetamine dependence.

  Toshiyuki Shirai, Satoshi Okazaki, Takaki Tanifuji, Ikuo Otsuka, Tadasu Horai, Kentaro Mouri, Yukihiro Takemura, Katsuro Aso, Noriya Yamamoto, Akitoyo Hishimoto

  Repeated abuse of methamphetamine (METH) can cause dependence, repeated relapse of psychotic symptoms, compulsive drug-seeking behaviour, and various neurological symptoms. These long-term biological changes may be associated with epigenetic mechanisms; however, the association between METH use and epigenetic mechanisms has been poorly investigated. Thus, we performed an epigenome-wide association study of METH dependence using genomic DNA extracted from the blood samples of 24 patients with METH dependence and 24 normal controls. All participants were of Japanese descent. We tested the association between METH dependence and DNA methylation using linear regression analysis. We found epigenome-wide significant associations at four CpG sites, one of which occurred in the CNOT1 gene and another in the PUM1 gene. We especially noted the CNOT1 and PUM1 genes as well as several other genes that indicated some degree of association with METH dependence. Among the relatively enriched Gene Ontology terms, we were interested in terms of mRNA metabolism, respirasome, and excitatory extracellular ligand-gated ion channel activity. Among the relatively enriched Kyoto Encyclopedia of Genes and Genome pathways, we noted pathways of several neurological diseases. Our results indicate that genetic changes akin to those in other psychiatric or neurodegenerative disorders may also occur via epigenetic mechanisms in patients with METH dependence.

  Mar. 2024, Addiction biology, 29(3) (3), e13383, English, International magazine

  Scientific journal


• GWAS Meta-Analysis of Suicide Attempt: Identification of 12 Genome-Wide Significant Loci and Implication of Genetic Risks for Specific Health Factors.

  International Suicide Genetics Consortium

  OBJECTIVE: Suicidal behavior is heritable and is a major cause of death worldwide. Two large-scale genome-wide association studies (GWASs) recently discovered and cross-validated genome-wide significant (GWS) loci for suicide attempt (SA). The present study leveraged the genetic cohorts from both studies to conduct the largest GWAS meta-analysis of SA to date. Multi-ancestry and admixture-specific meta-analyses were conducted within groups of significant African, East Asian, and European ancestry admixtures. METHODS: This study comprised 22 cohorts, including 43,871 SA cases and 915,025 ancestry-matched controls. Analytical methods across multi-ancestry and individual ancestry admixtures included inverse variance-weighted fixed-effects meta-analyses, followed by gene, gene-set, tissue-set, and drug-target enrichment, as well as summary-data-based Mendelian randomization with brain expression quantitative trait loci data, phenome-wide genetic correlation, and genetic causal proportion analyses. RESULTS: Multi-ancestry and European ancestry admixture GWAS meta-analyses identified 12 risk loci at p values <5×10-8. These loci were mostly intergenic and implicated DRD2, SLC6A9, FURIN, NLGN1, SOX5, PDE4B, and CACNG2. The multi-ancestry SNP-based heritability estimate of SA was 5.7% on the liability scale (SE=0.003, p=5.7×10-80). Significant brain tissue gene expression and drug set enrichment were observed. There was shared genetic variation of SA with attention deficit hyperactivity disorder, smoking, and risk tolerance after conditioning SA on both major depressive disorder and posttraumatic stress disorder. Genetic causal proportion analyses implicated shared genetic risk for specific health factors. CONCLUSIONS: This multi-ancestry analysis of suicide attempt identified several loci contributing to risk and establishes significant shared genetic covariation with clinical phenotypes. These findings provide insight into genetic factors associated with suicide attempt across ancestry admixture populations, in veteran and civilian populations, and in attempt versus death.

  Oct. 2023, American Journal of Psychiatry, 180(10) (10), 723 - 738, English, International magazine

  [Refereed]

  Scientific journal


• Accelerated epigenetic aging and decreased natural killer cells based on DNA methylation in patients with untreated major depressive disorder.

  Ryota Shindo, Takaki Tanifuji, Satoshi Okazaki, Ikuo Otsuka, Toshiyuki Shirai, Kentaro Mouri, Tadasu Horai, Akitoyo Hishimoto

  Major depressive disorder (MDD) is known to cause significant disability. Genome-wide DNA methylation (DNAm) profiles can be used to estimate biological aging and as epigenetic clocks. However, information on epigenetic clocks reported in MDD patients is inconsistent. Since antidepressants are likely confounders, we evaluated biological aging using various DNAm-based predictors in patients with MDD who had never received depression medication. A publicly available dataset consisting of whole blood samples from untreated MDD patients (n = 40) and controls (n = 40) was used. We analyzed five epigenetic clocks (HorvathAge, HannumAge, SkinBloodAge, PhenoAge, and GrimAge), DNAm-based telomere length (DNAmTL), and DNAm-based age-related plasma proteins (GrimAge components), as well as DNAm-based white blood cell composition. The results indicate that patients with untreated MDD were significantly associated with epigenetic aging acceleration in HannumAge and GrimAge. Furthermore, a decrease in natural killer cells, based on DNAm, was observed in patients with untreated MDD.

  Sep. 2023, npj aging, 9(1) (1), 19 - 19, English, International magazine

  Scientific journal


• Association of two variable number of tandem repeats in the monoamine oxidase A gene promoter with suicide completion: The present study and meta-analysis.

  Masashi Hasegawa, Takaki Tanifuji, Satoshi Okazaki, Ikuo Otsuka, Toshiyuki Shirai, Ryota Shindo, Tadasu Horai, Kentaro Mouri, Motonori Takahashi, Takeshi Kondo, Yasuhiro Ueno, Akitoyo Hishimoto

  BACKGROUND: One potential cause of suicide is serotonergic dysfunction. Sex differences have been reported to modulate the effects of serotonergic polymorphisms. Monoamine oxidase A (MAOA) is an enzyme that degrades serotonin and is located on the X chromosome. A previous study indicated that the upstream (u) variable number of tandem repeat (VNTR) in the MAOA gene promoter may be associated with suicide. However, a meta-analysis showed that this polymorphism may not be related to suicide. According to a recent study, compared with the uVNTR, the distal (d)VNTR and the haplotypes of the two VNTRs modulate MAOA expression. METHODS: We examined the two VNTRs in the MAOA gene promoter in 1007 subjects who committed suicide and 844 healthy controls. We analyzed the two VNTRs using fluorescence-based polymerase chain reaction assays. We conducted a meta-analysis for the two VNTRs to update it. RESULTS: Our results demonstrated that neither the genotype-based associations nor allele/haplotype frequencies of the two VNTRs were significantly associated with suicide. In the meta-analysis, we did not indicate relationships between uVNTR and suicide nor did we identify articles analyzing dVNTR in suicide. CONCLUSION: Overall, we did not find a relationship between the two VNTRs in the MAOA promoter and suicide completion; thus, warranting further studies are required.

  Sep. 2023, Neuropsychopharmacology reports, 43(3) (3), 338 - 345, English, International magazine

  Scientific journal


• Using brain cell-type-specific protein interactomes to interpret neurodevelopmental genetic signals in schizophrenia

  Yu-Han H. Hsu, Greta Pintacuda, Ruize Liu, Eugeniu Nacu, April Kim, Kalliopi Tsafou, Natalie Petrossian, William Crotty, Jung Min Suh, Jackson Riseman, Jacqueline M. Martin, Julia C. Biagini, Daya Mena, Joshua K.T. Ching, Edyta Malolepsza, Taibo Li, Tarjinder Singh, Tian Ge, Shawn B. Egri, Benjamin Tanenbaum, Caroline R. Stanclift, Annie M. Apffel, Stephan Ripke, Benjamin M. Neale, Aiden Corvin, James T.R. Walters, Kai-How Farh, Peter A. Holmans, Phil Lee, Brendan Bulik-Sullivan, David A. Collier, Hailiang Huang, Tune H. Pers, Ingrid Agartz, Esben Agerbo, Margot Albus, Madeline Alexander, Farooq Amin, Silviu A. Bacanu, Martin Begemann, Richard A. Belliveau, Judit Bene, Sarah E. Bergen, Elizabeth Bevilacqua, Tim B. Bigdeli, Donald W. Black, Richard Bruggeman, Nancy G. Buccola, Randy L. Buckner, William Byerley, Wiepke Cahn, Guiqing Cai, Dominique Campion, Rita M. Cantor, Vaughan J. Carr, Noa Carrera, Stanley V. Catts, Kimberley D. Chambert, Raymond C.K. Chan, Ronald Y.L. Chan, Eric Y.H. Chen, Wei Cheng, Eric FC. Cheung, Siow Ann Chong, C. Robert Cloninger, David Cohen, Nadine Cohen, Paul Cormican, Nick Craddock, James J. Crowley, David Curtis, Michael Davidson, Kenneth L. Davis, Franziska Degenhardt, Jurgen Del Favero, Ditte Demontis, Dimitris Dikeos, Timothy Dinan, Srdjan Djurovic, Gary Donohoe, Elodie Drapeau, Jubao Duan, Frank Dudbridge, Naser Durmishi, Peter Eichhammer, Johan Eriksson, Valentina Escott-Price, Laurent Essioux, Ayman H. Fanous, Martilias S. Farrell, Josef Frank, Lude Franke, Robert Freedman, Nelson B. Freimer, Marion Friedl, Joseph I. Friedman, Menachem Fromer, Giulio Genovese, Lyudmila Georgieva, Ina Giegling, Paola Giusti-Rodríguez, Stephanie Godard, Jacqueline I. Goldstein, Vera Golimbet, Srihari Gopal, Jacob Gratten, Lieuwe de Haan, Christian Hammer, Marian L. Hamshere, Mark Hansen, Thomas Hansen, Vahram Haroutunian, Annette M. Hartmann, Frans A. Henskens, Stefan Herms, Joel N. Hirschhorn, Per Hoffmann, Andrea Hofman, Mads V. Hollegaard, David M. Hougaard, Masashi Ikeda, Inge Joa, Antonio Julià, René S. Kahn, Luba Kalaydjieva, Sena Karachanak-Yankova, Juha Karjalainen, David Kavanagh, Matthew C. Keller, James L. Kennedy, Andrey Khrunin, Yunjung Kim, Janis Klovins, James A. Knowles, Bettina Konte, Vaidutis Kucinskas, Zita Ausrele Kucinskiene, Hana Kuzelova-Ptackova, Anna K. Kähler, Claudine Laurent, Jimmy Lee, S. Hong Lee, Sophie E. Legge, Bernard Lerer, Miaoxin Li, Tao Li, Kung-Yee Liang, Jeffrey Lieberman, Svetlana Limborska, Carmel M. Loughland, Jan Lubinski, Jouko Lönnqvist, Milan Macek, Patrik K.E. Magnusson, Brion S. Maher, Wolfgang Maier, Jacques Mallet, Sara Marsal, Manuel Mattheisen, Morten Mattingsdal, Robert W. McCarley, Colm McDonald, Andrew M. McIntosh, Sandra Meier, Carin J. Meijer, Bela Melegh, Ingrid Melle, Raquelle I. Mesholam-Gately, Andres Metspalu, Patricia T. Michie, Lili Milani, Vihra Milanova, Younes Mokrab, Derek W. Morris, Ole Mors, Kieran C. Murphy, Robin M. Murray, Inez Myin-Germeys, Bertram Müller-Myhsok, Mari Nelis, Igor Nenadic, Deborah A. Nertney, Gerald Nestadt, Kristin K. Nicodemus, Liene Nikitina-Zake, Laura Nisenbaum, Annelie Nordin, Eadbhard O'Callaghan, Colm O'Dushlaine, F. Anthony O'Neill, Sang-Yun Oh, Ann Olincy, Line Olsen, Jim Van Os, Christos Pantelis, George N. Papadimitriou, Sergi Papiol, Elena Parkhomenko, Michele T. Pato, Tiina Paunio, Milica Pejovic-Milovancevic, Diana O. Perkins, Olli Pietiläinen, Jonathan Pimm, Andrew J. Pocklington, John Powell, Alkes Price, Ann E. Pulver, Shaun M. Purcell, Digby Quested, Henrik B. Rasmussen, Abraham Reichenberg, Mark A. Reimers, Alexander L. Richards, Joshua L. Roffman, Panos Roussos, Douglas M. Ruderfer, Veikko Salomaa, Alan R. Sanders, Ulrich Schall, Christian R. Schubert, Thomas G. Schulze, Sibylle G. Schwab, Edward M. Scolnick, Rodney J. Scott, Larry J. Seidman, Jianxin Shi, Engilbert Sigurdsson, Teimuraz Silagadze, Jeremy M. Silverman, Kang Sim, Petr Slominsky, Jordan W. Smoller, Hon-Cheong So, Chris C.A. Spencer, Eli A. Stahl, Hreinn Stefansson, Stacy Steinberg, Elisabeth Stogmann, Richard E. Straub, Eric Strengman, Jana Strohmaier, T Scott Stroup, Mythily Subramaniam, Jaana Suvisaari, Dragan M. Svrakic, Jin P. Szatkiewicz, Erik Söderman, Srinivas Thirumalai, Draga Toncheva, Sarah Tosato, Juha Veijola, John Waddington, Dermot Walsh, Dai Wang, Qiang Wang, Bradley T. Webb, Mark Weiser, Dieter B. Wildenauer, Nigel M. Williams, Stephanie Williams, Stephanie H. Witt, Aaron R. Wolen, Emily H.M. Wong, Brandon K. Wormley, Hualin Simon Xi, Clement C. Zai, Xuebin Zheng, Fritz Zimprich, Naomi R. Wray, Kari Stefansson, Peter M. Visscher, Rolf Adolfsson, Ole A. Andreassen, Douglas H.R. Blackwood, Elvira Bramon, Joseph D. Buxbaum, Anders D. Børglum, Sven Cichon, Ariel Darvasi, Enrico Domenici, Hannelore Ehrenreich, Tõnu Esko, Pablo V. Gejman, Michael Gill, Hugh Gurling, Christina M. Hultman, Nakao Iwata, Assen V. Jablensky, Erik G. Jönsson, Kenneth S. Kendler, George Kirov, Jo Knight, Todd Lencz, Douglas F. Levinson, Qingqin S. Li, Jianjun Liu, Anil K. Malhotra, Steven A. McCarroll, Andrew McQuillin, Jennifer L. Moran, Preben B. Mortensen, Bryan J. Mowry, Markus M. Nöthen, Roel A. Ophoff, Michael J. Owen, Aarno Palotie, Carlos N. Pato, Tracey L. Petryshen, Danielle Posthuma, Marcella Rietschel, Brien P. Riley, Dan Rujescu, Pak C. Sham, Pamela Sklar, David St Clair, Daniel R. Weinberger, Jens R. Wendland, Thomas Werge, Mark J. Daly, Patrick F. Sullivan, Michael C. O'Donovan, Hailiang Huang, Shengying Qin, Akira Sawa, Sibylle G. Schwab, Rene Kahn, Kyung Sue Hong, Wenzhao Shi, Ming Tsuang, Masanari Itokawa, Gang Feng, Jianjun Liu, Stephen J. Glatt, Nakao Iwata, Masashi Ikeda, Xiancang Ma, Jimmy Lee, Jinsong Tang, Yunfeng Ruan, Ruize Liu, Feng Zhu, Yasue Horiuchi, Byung Dae Lee, Eun-Jeong Joo, Woojae Myung, Kyooseob Ha, Hong-Hee Won, Ji Hyung Baek, Young Chul Chung, Sung-Wan Kim, Dieter B. Wildenauer, Agung Kusumawardhani, Wei J. Chen, Hai-Gwo Hwu, Kang Sim, Akitoyo Hishimoto, Ikuo Otsuka, Ichiro Sora, Tomoko Toyota, Takeo Yoshikawa, Hiroshi Kunugi, Kotaro Hattori, Sayuri Ishiwata, Shusuke Numata, Tetsuro Ohmori, Makoto Arai, Yuji Ozeki, Kumiko Fujii, Se Joo Kim, Heon-Jeong Lee, Yong Min Ahn, Se Hyun Kim, Kazufumi Akiyama, Kazutaka Shimoda, Makoto Kinoshita, Steven A. Carr, Monica Schenone, Jake Jaffe, Nadine Fornelos, Hailiang Huang, Kevin C. Eggan, Kasper Lage

  Elsevier BV, May 2023, iScience, 26(5) (5), 106701 - 106701

  Scientific journal


• Physiologically-based pharmacokinetic model to investigate the effect of pregnancy on risperidone and paliperidone pharmacokinetics: Application to a pregnant woman and her neonate.

  Walaa Y B Mahdy, Kazuhiro Yamamoto, Takahiro Ito, Naoko Fujiwara, Kazumichi Fujioka, Tadasu Horai, Ikuo Otsuka, Hitomi Imafuku, Tomohiro Omura, Kazumoto Iijima, Ikuko Yano

  This study aimed to determine the effects of pregnancy and ontogeny on risperidone and paliperidone pharmacokinetics by assessing their serum concentrations in two subjects and constructing a customized physiologically-based pharmacokinetic (PBPK) model. Risperidone and paliperidone serum concentrations were determined in a pregnant woman and her newborn. PBPK models for risperidone and paliperidone in adults, pediatric, and pregnant populations were developed and verified using the Simcyp simulator. These models were then applied to our two subjects, generating their "virtual twins." Effects of pregnancy on both drugs were examined using models with fixed pharmacokinetic parameters. In the neonatal PBPK simulation, 10 different models for estimating the renal function of neonates were evaluated. Risperidone was not detected in the serum of both pregnant woman and her newborn. Maternal and neonatal serum paliperidone concentrations were between 2.05-3.80 and 0.82-1.03 ng/ml, respectively. Developed PBPK models accurately predicted paliperidone's pharmacokinetics, as shown by minimal bias and acceptable precision across populations. The individualized maternal model predicted all observed paliperidone concentrations within the 90% prediction interval. Fixed-parameter simulations showed that CYP2D6 activity largely affects risperidone and paliperidone pharmacokinetics during pregnancy. The Flanders metadata equation showed the lowest absolute bias (mean error: 22.3% ± 6.0%) and the greatest precision (root mean square error: 23.8%) in predicting paliperidone plasma concentration in the neonatal population. Our constructed PBPK model can predict risperidone and paliperidone pharmacokinetics in pregnant and neonatal populations, which could help with precision dosing using the PBPK model-informed approach in special populations.

  Apr. 2023, Clinical and translational science, 16(4) (4), 618 - 630, English, International magazine

  Scientific journal


• Epigenetic clock analysis reveals increased plasma cystatin C levels based on DNA methylation in major depressive disorder.

  Takaki Tanifuji, Satoshi Okazaki, Ikuo Otsuka, Kentaro Mouri, Tadasu Horai, Ryota Shindo, Toshiyuki Shirai, Akitoyo Hishimoto

  Major depressive disorder (MDD) is a common mental illness and a major public health concern worldwide. Depression is associated with epigenetic changes that regulate gene expression, and analyzing these changes may help elucidate the pathophysiology of MDD. Genome-wide DNA methylation (DNAm) profiles can function as 'epigenetic clocks' that can help estimate biological aging. Here, we assessed biological aging in patients with MDD using various DNAm-based indicators of epigenetic aging. We used a publicly available dataset containing data obtained from the whole blood samples of MDD patients (n = 489) and controls (n = 210). We analyzed five epigenetic clocks (HorvathAge, HannumAge, SkinBloodAge, PhenoAge, and GrimAge) and DNAm-based telomere length (DNAmTL). We also investigated seven DNAm-based age-predictive plasma proteins (including cystatin C) and smoking status, which are components of GrimAge. Following adjustment for confounding factors such as age and sex, patients with MDD showed no significant difference in epigenetic clocks and DNAmTL. However, DNAm-based plasma cystatin C levels were significantly higher in patients with MDD than controls. Our findings revealed specific DNAm changes predicting plasma cystatin C levels in MDD. These findings may help elucidate the pathophysiology of MDD, leading to the development of new biomarkers and medications.

  Apr. 2023, Psychiatry research, 322, 115103 - 115103, English, International magazine

  Scientific journal


• Mapping the genetic architecture of suicide attempt and suicide death using polygenic risk scores for clinically-related psychiatric disorders and traits.

  Otsuka I, Galfalvy H, Guo J, Akiyama M, Rujescu D, Turecki G, Hishimoto A, Mann JJ.

  BACKGROUND: Suicidal behavior is moderately heritable and a consequence of a combination of the diathesis traits for suicidal behavior and suicide-related major psychiatric disorders. Here, we sought to examine shared polygenic effects between various psychiatric disorders/traits and suicidal behavior and to compare the shared polygenic effects of various psychiatric disorders/traits on non-fatal suicide attempt and suicide death. METHODS: We used our genotyped European ancestry sample of 260 non-fatal suicide attempters, 317 suicide decedents and 874 non-psychiatric controls to test whether polygenic risk scores (PRSs) obtained from large GWASs for 22 suicide-related psychiatric disorders/traits were associated with suicidal behavior. Results were compared between non-fatal suicide attempt and suicide death in a sensitivity analysis. RESULTS: PRSs for major depressive disorder, bipolar disorder, schizophrenia, ADHD, alcohol dependence, sensitivity to environmental stress and adversity, educational attainment, cognitive performance, and IQ were associated with suicidal behavior (Bonferroni-corrected p < 2.5 × 10-4). The polygenic effects of all 22 psychiatric disorders/traits had the same direction (p for binomial tests = 4.8 × 10-7) and were correlated (Spearman's ρ = 0.85) between non-fatal suicide attempters and suicide decedents. CONCLUSIONS: We found that polygenic effects for major psychiatric disorders and diathesis-related traits including stress responsiveness and intellect/cognitive function contributed to suicidal behavior. While we found comparable polygenic architecture between non-fatal suicide attempters and suicide decedents based on correlations with PRSs of suicide-related psychiatric disorders/traits, our analyses are limited by small sample size resulting in low statistical power to detect difference between non-fatal suicide attempt and suicide death.

  Lead, Apr. 2023, Psychological Medicine, 53(6) (6), 2689 - 2697, English, International magazine

  [Refereed]

  Scientific journal


• Effective use of memantine for catatonia in major depressive disorder after failure of electroconvulsive therapy: A case report.

  Takaki Tanifuji, Ikuo Otsuka, Toshio Atarashiya, Atsushi Kimura, Tadasu Horai, Satoshi Okazaki, Akitoyo Hishimoto

  Mar. 2023, PCN reports : psychiatry and clinical neurosciences, 2(1) (1), e84, English, International magazine

  Scientific journal


• Identification of Novel, Replicable Genetic Risk Loci for Suicidal Thoughts and Behaviors Among US Military Veterans

  Nathan A. Kimbrel, Allison E. Ashley-Koch, Xue J. Qin, Jennifer H. Lindquist, Melanie E. Garrett, Michelle F. Dennis, Lauren P. Hair, Jennifer E. Huffman, Daniel A. Jacobson, Ravi K. Madduri, Jodie A. Trafton, Hilary Coon, Anna R. Docherty, Niamh Mullins, Douglas M. Ruderfer, Philip D. Harvey, Benjamin H. McMahon, David W. Oslin, Jean C. Beckham, Elizabeth R. Hauser, Michael A. Hauser, Khushbu Agarwal, Allison E. Ashley-Koch, Mihaela Aslan, Jean C. Beckham, Edmond Begoli, Tanmoy Bhattacharya, Ben Brown, Patrick S. Calhoun, Kei-Hoi Cheung, Sutanay Choudhury, Ashley M. Cliff, Judith D. Cohn, Silvia Crivelli, Leticia Cuellar-Hengartner, Haedi E. Deangelis, Michelle F. Dennis, Sayera Dhaubhadel, Patrick D. Finley, Kumkum Ganguly, Michael R. Garvin, Joel E. Gelernter, Lauren P. Hair, Phillip D. Harvey, Elizabeth R. Hauser, Michael A. Hauser, Nick W. Hengartner, Daniel A. Jacobson, Piet C. Jones, David Kainer, Alan D. Kaplan, Ira R. Katz, Rachel L. Kember, Nathan A. Kimbrel, Angela C. Kirby, John C. Ko, Beauty Kolade, John H. Lagergren, Matthew J. Lane, Daniel F. Levey, Drew Levin, Jennifer H. Lindquist, Xianlian Liu, Ravi K. Madduri, Carrie Manore, Susana B. Martins, John F. McCarthy, Mikaela McDevitt-Cashman, Benjamin H. McMahon, Izaak Miller, Destinee Morrow, David W. Oslin, Mirko Pavicic-Venegas, John Pestian, Saiju Pyarajan, Xue J. Qin, Nallakkandi Rajeevan, Christine M. Ramsey, Ruy Ribeiro, Alex Rodriguez, Jonathan Romero, Daniel Santel, Noah Schaefferkoetter, Yunling Shi, Murray B. Stein, Kyle Sullivan, Ning Sun, Suzanne R. Tamang, Alice Townsend, Jodie A. Trafton, Angelica Walker, Xiange Wang, Victoria Wangia-Anderson, Renji Yang, Hong-Jun Yoon, Shinjae Yoo, Rafael Zamora-Resendiz, Hongyu Zhao, Anna R Docherty, Niamh Mullins, Jonathan R I Coleman, Andrey Shabalin, JooEun Kang, Balasz Murnyak, Frank Wendt, Mark Adams, Adrian I Campos, Emily DiBlasi, Janice M Fullerton, Henry R Kranzler, Amanda Bakian, Eric T Monson, Miguel E Rentería, Ole A Andreassen, Cynthia M Bulik, Howard J Edenberg, Ronald C Kessler, J John Mann, John I. Nurnberger, Giorgio Pistis, Fabian Streit, Robert J Ursano, Swapnil Awasthi, Andrew W Bergen, Wade H Berrettini, Martin Bohus, Harry Brandt, Xiao Chang, Hsi-Chung Chen, Wei J Chen, Erik D Christensen, Steven Crawford, Scott Crow, Philibert Duriez, Alexis C Edwards, Fernando Fernández-Aranda, Manfred M Fichter, Hanga Galfalvy, Steven Gallinger, Michael Gandal, Philip Gorwood, Yiran Guo, Jonathan D Hafferty, Hakon Hakonarson, Katherine A Halmi, Akitoyo Hishimoto, Sonia Jain, Stéphane Jamain, Susana Jiménez-Murcia, Craig Johnson, Allan S Kaplan, Walter H Kaye, Pamela K Keel, James L Kennedy, Minsoo Kim, Kelly L Klump, Daniel F Levey, Dong Li, Shih-Cheng Liao, Klaus Lieb, Lisa Lilenfeld, Adriana Lori, Pierre J Magistretti, Christian R Marshall, James E Mitchell, Richard M Myers, Satoshi Okazaki, Ikuo Otsuka, Dalila Pinto, Abigail Powers, Nicolas Ramoz, Stephan Ripke, Stefan Roepke, Vsevolod Rozanov, Stephen W Scherer, Christian Schmahl, Marcus Sokolowski, Anna Starnawska, Michael Strober, Mei-Hsin Su, Laura M Thornton, Janet Treasure, Erin B Ware, Hunna J Watson, Stephanie H Witt, D Blake Woodside, Zeynep Yilmaz, Lea Zillich, Esben Agerbo, Anders D Børglum, Gerome Breen, Ditte Demontis, Annette Erlangsen, Tõnu Esko, Joel Gelernter, Stephen J Glatt, David M Hougaard, Hai-Gwo Hwu, Po-Hsiu Kuo, Cathryn M Lewis, Qingqin S Li, Chih-Min Liu, Nicholas G Martin, Andrew M McIntosh, Sarah E Medland, Ole Mors, Merete Nordentoft, John I Nurnberger, Catherine Olsen, David Porteous, Daniel J Smith, Eli A Stahl, Murray B Stein, Danuta Wasserman, Thomas Werge, David C Whiteman, Virginia Willour, Hilary Coon, Douglas M Ruderfer, Eric Dedert, Eric B. Elbogen, John A. Fairbank, Robin A. Hurley, Jason D. Kilts, Sarah L. Martindale, Christine E. Marx, Scott D. McDonald, Scott D. Moore, Rajendra A. Morey, Jennifer C. Naylor, Jared Rowland, Robert D. Shura, Cindy Swinkels, Larry A. Tupler, Elizabeth E. Van Voorhees, Ruth Yoash-Gantz, J. Michael Gaziano, Sumitra Muralidhar, Rachel Ramoni, Kyong-Mi Chang, Christopher J. O’Donnell, Philip S. Tsao, James Breeling, Elizabeth Hauser, Yan Sun, Grant Huang, Juan P. Casas, Jennifer Moser, Stacey B. Whitbourne, Jessica V. Brewer, Todd Conner, Dean P. Argyres, Brady Stephens, Mary T. Brophy, Donald E. Humphries, Luis E. Selva, Nhan Do, Shahpoor (Alex) Shayan, Kelly Cho, Lori Churby, Peter Wilson, Rachel McArdle, Louis Dellitalia, Kristin Mattocks, John Harley, Jeffrey Whittle, Frank Jacono, John Wells, Salvador Gutierrez, Gretchen Gibson, Kimberly Hammer, Laurence Kaminsky, Gerardo Villareal, Scott Kinlay, Junzhe Xu, Mark Hamner, Roy Mathew, Sujata Bhushan, Pran Iruvanti, Michael Godschalk, Zuhair Ballas, Douglas Ivins, Stephen Mastorides, Jonathan Moorman, Saib Gappy, Jon Klein, Nora Ratcliffe, Hermes Florez, Olaoluwa Okusaga, Maureen Murdoch, Peruvemba Sriram, Shing Shing Yeh, Neeraj Tandon, Darshana Jhala, Suthat Liangpunsakul, Kris Ann Oursler, Mary Whooley, Sunil Ahuja, Joseph Constans, Paul Meyer, Jennifer Greco, Michael Rauchman, Richard Servatius, Melinda Gaddy, Agnes Wallbom, Timothy Morgan, Todd Stapley, Scott Sherman, George Ross, Patrick Strollo, Edward Boyko, Laurence Meyer, Samir Gupta, Mostaqul Huq, Joseph Fayad, Adriana Hung, Jack Lichy, Robin Hurley, Brooks Robey, Robert Striker

  Importance Suicide is a leading cause of death; however, the molecular genetic basis of suicidal thoughts and behaviors (SITB) remains unknown. Objective To identify novel, replicable genomic risk loci for SITB. Design, Setting, and Participants This genome-wide association study included 633 778 US military veterans with and without SITB, as identified through electronic health records. GWAS was performed separately by ancestry, controlling for sex, age, and genetic substructure. Cross-ancestry risk loci were identified through meta-analysis. Study enrollment began in 2011 and is ongoing. Data were analyzed from November 2021 to August 2022. Main Outcome and Measures SITB. Results A total of 633 778 US military veterans were included in the analysis (57 152 [9%] female; 121 118 [19.1%] African ancestry, 8285 [1.3%] Asian ancestry, 452 767 [71.4%] European ancestry, and 51 608 [8.1%] Hispanic ancestry), including 121 211 individuals with SITB (19.1%). Meta-analysis identified more than 200 GWS (P &amp;lt; 5 × 10⁻⁸) cross-ancestry risk single-nucleotide variants for SITB concentrated in 7 regions on chromosomes 2, 6, 9, 11, 14, 16, and 18. Top single-nucleotide variants were largely intronic in nature; 5 were independently replicated in ISGC, including rs6557168 in ESR1, rs12808482 in DRD2, rs77641763 in EXD3, rs10671545 in DCC, and rs36006172 in TRAF3. Associations for FBXL19 and AC018880.2 were not replicated. Gene-based analyses implicated 24 additional GWS cross-ancestry risk genes, including FURIN, TSNARE1, and the NCAM1-TTC12-ANKK1-DRD2 gene cluster. Cross-ancestry enrichment analyses revealed significant enrichment for expression in brain and pituitary tissue, synapse and ubiquitination processes, amphetamine addiction, parathyroid hormone synthesis, axon guidance, and dopaminergic pathways. Seven other unique European ancestry–specific GWS loci were identified, 2 of which (POM121L2 and METTL15/LINC02758) were replicated. Two additional GWS ancestry-specific loci were identified within the African ancestry (PET112/GATB) and Hispanic ancestry (intergenic locus on chromosome 4) subsets, both of which were replicated. No GWS loci were identified within the Asian ancestry subset; however, significant enrichment was observed for axon guidance, cyclic adenosine monophosphate signaling, focal adhesion, glutamatergic synapse, and oxytocin signaling pathways across all ancestries. Within the European ancestry subset, genetic correlations (r &amp;gt; 0.75) were observed between the SITB phenotype and a suicide attempt-only phenotype, depression, and posttraumatic stress disorder. Additionally, polygenic risk score analyses revealed that the Million Veteran Program polygenic risk score had nominally significant main effects in 2 independent samples of veterans of European and African ancestry. Conclusions and Relevance The findings of this analysis may advance understanding of the molecular genetic basis of SITB and provide evidence for ESR1, DRD2, TRAF3, and DCC as cross-ancestry candidate risk genes. More work is needed to replicate these findings and to determine if and how these genes might impact clinical care.

  American Medical Association (AMA), Feb. 2023, JAMA Psychiatry, 80(2) (2), 135 - 135

  Scientific journal


• Ribosomal DNA gene copies are increased in blood and brain of Japanese schizophrenia patients.

  Sen Li, Ikuo Otsuka, Takaki Tanifuji, Satoshi Okazaki, Tadasu Horai, Motonori Takahashi, Takeshi Kondo, Yasuhiro Ueno, Akitoyo Hishimoto

  Past evidence has indicated increased ribosomal DNA (rDNA) content in the blood of patients with schizophrenia (SCZ) among European populations. Here, for the first time, we investigated the rDNA copy number (rDNAcn) of SCZ in East Asian populations as well as in blood and brain tissues. In this study, we measured 18S/28S rDNAcn in the peripheral blood of live participants (81 patients with SCZ and 98 healthy controls) and the dorsolateral prefrontal cortices (DLPFCs) of postmortem individuals (10 patients with SCZ and 23 non-psychiatric controls) in the Japanese population. Patients with SCZ had significantly increased 18S/28S rDNAcn in the blood compared to controls (p < 0.05). 18S rDNAcn was significantly increased in the brain of patients with SCZ compared to controls (p < 0.05). In conclusion, regarding the increased rDNAcn in the blood of patients with SCZ that was previously reported in Europeans, we successfully replicated this by using a different, ethnically East Asian, cohort. Additionally, we provide the first evidence of increased rDNAcn in the brain of patients with SCZ. These findings may help to elucidate the molecular underpinnings of SCZ pathophysiology related to ribosomal DNA abnormalities.

  2023, PloS one, 18(1) (1), e0280694, English, International magazine

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Association of SLC6A3 variants with treatment-resistant schizophrenia: a genetic association study of dopamine-related genes in schizophrenia.

  Masanobu Kogure, Nobuhisa Kanahara, Atsuhiro Miyazawa, Yuki Shiko, Ikuo Otsuka, Koichi Matsuyama, Masayuki Takase, Makoto Kimura, Hiroshi Kimura, Kiyomitsu Ota, Keita Idemoto, Masaki Tamura, Yasunori Oda, Taisuke Yoshida, Satoshi Okazaki, Fumiaki Yamasaki, Yusuke Nakata, Yoshinori Watanabe, Tomihisa Niitsu, Akitoyo Hishimoto, Masaomi Iyo

  BACKGROUND: Most genetic analyses that have attempted to identify a locus or loci that can distinguish patients with treatment-resistant schizophrenia (TRS) from those who respond to treatment (non-TRS) have failed. However, evidence from multiple studies suggests that patients with schizophrenia who respond well to antipsychotic medication have a higher dopamine (DA) state in brain synaptic clefts whereas patients with TRS do not show enhanced DA synthesis/release pathways. PATIENTS AND METHODS: To examine the contribution (if any) of genetics to TRS, we conducted a genetic association analysis of DA-related genes in schizophrenia patients (TRS, n = 435; non-TRS, n = 539) and healthy controls (HC: n = 489). RESULTS: The distributions of the genotypes of rs3756450 and the 40-bp variable number tandem repeat on SLC6A3 differed between the TRS and non-TRS groups. Regarding rs3756450, the TRS group showed a significantly higher ratio of the A allele, whereas the non-TRS group predominantly had the G allele. The analysis of the combination of COMT and SLC6A3 yielded a significantly higher ratio of the putative low-DA type (i.e., high COMT activity + high SLC6A3 activity) in the TRS group compared to the two other groups. Patients with the low-DA type accounted for the minority of the non-TRS group and exhibited milder psychopathology. CONCLUSION: The overall results suggest that (i) SLC6A3 could be involved in responsiveness to antipsychotic medication and (ii) genetic variants modulating brain DA levels may be related to the classification of TRS and non-TRS.

  2023, Frontiers in psychiatry, 14, 1334335 - 1334335, English, International magazine

  Scientific journal


• Epigenetic aging in Williams syndrome.

  Satoshi Okazaki, Ryo Kimura, Ikuo Otsuka, Kiyotaka Tomiwa, Yasuko Funabiki, Masatoshi Hagiwara, Toshiya Murai, Akitoyo Hishimoto

  BACKGROUND: Williams syndrome (WS) is a rare genetic disorder caused by a microdeletion at the 7q11.23 region and is characterized by diverse symptoms encompassing physical and cognitive features. WS was reported to be associated to altered DNA methylation (DNAm) patterns. However, due to the limited information from long-term studies, it remains unclear whether WS accelerates aging. Genome-wide DNAm profiles can serve as "epigenetic clocks" to help estimate biological aging along with age-related markers, such as plasma proteins and telomere length. METHODS: We investigated GrimAge, DNAm-based telomere length (DNAmTL), and other epigenetic clocks in blood samples of 32 patients with WS and 32 healthy controls. RESULTS: We observed a significant acceleration in GrimAge, DNAmTL, and other epigenetic clocks in patients with WS as compared with those of controls. In addition, several GrimAge components, such as adrenomedullin, growth differentiation factor-15, leptin and plasminogen activator inhibitor-1, were altered in patients with WS. CONCLUSIONS: This study provides novel evidence supporting the hypothesis that WS may be associated to accelerated biological aging. A better understanding of the overall underlying biological effects of WS can provide new foundations for improved patient care; thus, long-term follow-up studies are still warranted.

  Dec. 2022, Journal of child psychology and psychiatry, and allied disciplines, 63(12) (12), 1553 - 1562, English, International magazine

  Scientific journal


• Preventive effects of preoperative ramelteon on postoperative delirium in Asian elderly population: A randomized, double-blind, placebo-controlled trial, and a systematic review and meta-analysis.

  Takaki Tanifuji, Ikuo Otsuka, Satoshi Okazaki, Tadasu Horai, Ryuhei So, Kyoichi Shiroiwa, Kentaro Mouri, Motofumi Tanaka, Nobuko Ohmoto, Ichiro Sora, Midori Hirai, Takumi Fukumoto, Yonson Ku, Akitoyo Hishimoto

  Dec. 2022, Asian journal of psychiatry, 78, 103282 - 103282, English, International magazine


• Successful electroconvulsive therapy for 22q11.2 deletion syndrome with Schizophrenia and Parkinson's disease.

  Takaki Tanifuji, Ikuo Otsuka, Atsushi Kimura, Tadasu Horai, Satoshi Okazaki, Wataru Satake, Akitoyo Hishimoto

  Nov. 2022, Psychiatry and clinical neurosciences, 76(11) (11), 603 - 604, English, International magazine


• Epigenetic clock analysis in methamphetamine dependence.

  Yukihiro Takemura, Takaki Tanifuji, Satoshi Okazaki, Yutaka Shinko, Ikuo Otsuka, Tadasu Horai, Toshiyuki Shirai, Katsuro Aso, Noriya Yamamoto, Akitoyo Hishimoto

  Methamphetamine (MA) is used worldwide and causes serious public health and social problems. MA affects the central nervous, cardiac, and immune systems, which causes neuropsychiatric and cardiovascular diseases and infection. Epigenetic changes, including DNA methylation (DNAm), are associated with various clinical phenotypes of MA abuse. DNAm is related to biological aging and health risks; hence, we aimed to assess the changes in biological aging in MA dependence using the DNAm age and DNA methylation-based telomere length (DNAmTL). We used five measures of DNAm age (HorvathAge, HannumAge, SkinBloodAge, PhenoAge, and GrimAge), DNAmTL, and DNAm-based age-predictive factors (plasma proteins and blood cell composition). We compared patients with MA dependence and healthy controls (n = 24 each) using the DNAm profiles obtained from whole-blood samples. Patients with MA dependence showed significant acceleration in PhenoAge and GrimAge, as well as a trend for significant acceleration in DNAmTL. Following adjustment for confounding factors, MA dependence was significantly associated with accelerations in PhenoAge, GrimAge, and DNAmTL, as well as alterations in DNAm-based age-predictive factors (beta-2-microglobulin, granulocytes, and naive cluster of differentiation 4+ T cells). Our results suggested an acceleration of biological aging and specific changes in the DNAm of age- predictive factors in MA dependence.

  Nov. 2022, Psychiatry research, 317, 114901 - 114901, English, International magazine

  Scientific journal


• Improving polygenic prediction in ancestrally diverse populations

  Yunfeng Ruan, Yen-Feng Lin, Yen-Chen Anne Feng, Chia-Yen Chen, Max Lam, Zhenglin Guo, Yong Min Ahn, Kazufumi Akiyama, Makoto Arai, Ji Hyun Baek, Wei J. Chen, Young-Chul Chung, Gang Feng, Kumiko Fujii, Stephen J. Glatt, Kyooseob Ha, Kotaro Hattori, Teruhiko Higuchi, Akitoyo Hishimoto, Kyung Sue Hong, Yasue Horiuchi, Hai-Gwo Hwu, Masashi Ikeda, Sayuri Ishiwata, Masanari Itokawa, Nakao Iwata, Eun-Jeong Joo, Rene S. Kahn, Sung-Wan Kim, Se Joo Kim, Se Hyun Kim, Makoto Kinoshita, Hiroshi Kunugi, Agung Kusumawardhani, Jimmy Lee, Byung Dae Lee, Heon-Jeong Lee, Jianjun Liu, Ruize Liu, Xiancang Ma, Woojae Myung, Shusuke Numata, Tetsuro Ohmori, Ikuo Otsuka, Yuji Ozeki, Sibylle G. Schwab, Wenzhao Shi, Kazutaka Shimoda, Kang Sim, Ichiro Sora, Jinsong Tang, Tomoko Toyota, Ming Tsuang, Dieter B. Wildenauer, Hong-Hee Won, Takeo Yoshikawa, Alice Zheng, Feng Zhu, Lin He, Akira Sawa, Alicia R. Martin, Shengying Qin, Hailiang Huang, Tian Ge

  Springer Science and Business Media LLC, May 2022, Nature Genetics, 54(5) (5), 573 - 580

  Scientific journal


• Novel missense SETD1A variants in Japanese patients with schizophrenia: Resequencing and association analysis.

  Ryo Morikawa, Yuichiro Watanabe, Hirofumi Igeta, Reza K Arta, Masashi Ikeda, Satoshi Okazaki, Satoshi Hoya, Takeo Saito, Ikuo Otsuka, Jun Egawa, Takaki Tanifuji, Nakao Iwata, Toshiyuki Someya

  SETD1A has been identified as a substantial risk gene for schizophrenia. To further investigate the role of SETD1A in the genetic etiology of schizophrenia in the Japanese population, we performed resequencing and association analyses. First, we resequenced the SETD1A coding regions of 974 patients with schizophrenia. Then, we genotyped variants, prioritized via resequencing, in 2,027 patients with schizophrenia and 2,664 controls. Next, we examined the association between SETD1A and schizophrenia in 3,001 patients with schizophrenia and 2,664 controls. Finally, we performed a retrospective chart review of patients with prioritized SETD1A variants. We identified two novel missense variants (p.Ser575Pro and p.Glu857Gln) via resequencing. We did not detect these variants in 4,691 individuals via genotyping. These variants were not significantly associated with schizophrenia in the association analysis. Additionally, we found that a schizophrenia patient with the p.Glu857Gln variant had developmental delays. In conclusion, novel SETD1A missense variants were exclusively identified in Japanese patients with schizophrenia. However, our study does not provide evidence for the contribution of these variants to the genetic etiology of schizophrenia in the Japanese population.

  Apr. 2022, Psychiatry research, 310, 114481 - 114481, English, International magazine

  Scientific journal


• A preliminary genetic association study of GAD1 and GABAB receptor genes in patients with treatment-resistant schizophrenia.

  Atsuhiro Miyazawa, Nobuhisa Kanahara, Masanobu Kogure, Ikuo Otsuka, Satoshi Okazaki, Yoshinori Watanabe, Fumiaki Yamasaki, Yusuke Nakata, Yasunori Oda, Akitoyo Hishimoto, Masaomi Iyo

  BACKGROUND: GABAergic system dysfunction has been implicated in the etiology of schizophrenia and of cognitive impairments in particular. Patients with treatment-resistant schizophrenia (TRS) generally suffer from profound cognitive impairments in addition to severe positive symptoms, suggesting that GABA system dysfunction could be involved more closely in patients with TRS. METHODS AND RESULTS: In the present study, exome sequencing was conducted on fourteen TRS patients, whereby four SNPs were identified on GAD1, GABBR1 and GABBR2 genes. An association study for five SNPs including these 4 SNPs and rs3749034 on GAD1 as then performed among 357 patients with TRS, 682 non-TRS patients and 508 healthy controls (HC). The results revealed no significant differences in allelic and/or genetic distributions for any of the five SNPs. However, several subanalyses in comparisons between schizophrenia and HC groups, as well as between the three groups, showed nominal-level significance for rs3749034 on GAD1 and rs10985765/rs3750344 on GABBR2. In particular, in comparisons of female subjects, rigorous analysis for rs3749034 showed a statistical difference between the schizophrenia and HC groups and between the TRS and HC groups. CONCLUSIONS: Several positive results in subanalyses suggested that genetic vulnerability in the GABA system to schizophrenia or TRS could be affected by sex or sampling area, and overall, that rs3749034 on GAD1 and rs10985765 on GABBR2 could be related to TRS. In the present study, only a few SNPs were examined; it is possible that other important genetic variants in other regions of GABA-related genes were not captured in this preliminary study.

  Mar. 2022, Molecular biology reports, 49(3) (3), 2015 - 2024, English, International magazine

  Scientific journal


• Searching for biomarkers in schizophrenia and psychosis: Case-control study using capillary electrophoresis and liquid chromatography time-of-flight mass spectrometry and systematic review for biofluid metabolites.

  Saehyeon Kim, Satoshi Okazaki, Ikuo Otsuka, Yutaka Shinko, Tadasu Horai, Naofumi Shimmyo, Takashi Hirata, Naruhisa Yamaki, Takaki Tanifuji, Shuken Boku, Ichiro Sora, Akitoyo Hishimoto

  Metabolomics has been attracting attention in recent years as an objective method for diagnosing schizophrenia. In this study, we analyzed 378 metabolites in the serum of schizophrenia patients using capillary electrophoresis- and liquid chromatography-time-of-flight mass spectrometry. Using multivariate analysis with the orthogonal partial least squares method, we observed significantly higher levels of alanine, glutamate, lactic acid, ornithine, and serine and significantly lower levels of urea, in patients with chronic schizophrenia compared to healthy controls. Additionally, levels of fatty acids (15:0), (17:0), and (19:1), cis-11-eicosenoic acid, and thyroxine were significantly higher in patients with acute psychosis than in those in remission. Moreover, we conducted a systematic review of comprehensive metabolomics studies on schizophrenia over the last 20 years and observed consistent trends of increase in some metabolites such as glutamate and glucose, and decrease in citrate in schizophrenia patients across several studies. Hence, we provide substantial evidence for metabolic biomarkers in schizophrenia patients through our metabolomics study.

  Mar. 2022, Neuropsychopharmacology reports, 42(1) (1), 42 - 51, English, International magazine

  Scientific journal


• Accelerated epigenetic age and shortened telomere length based on DNA methylation in Nicolaides-Baraitser syndrome.

  Yutaka Shinko, Satoshi Okazaki, Ikuo Otsuka, Tadasu Horai, Saehyeon Kim, Takaki Tanifuji, Akitoyo Hishimoto

  BACKGROUND: Nicolaides-Baraitser syndrome (NCBRS) is a rare disorder characterized by neurodevelopmental delays, seizures, and diverse physical characteristics. The DNA methylation (DNAm) profile in NCBRS is significantly different. DNAm is linked to the biological aging of cells and the health risks associated with biological aging. In this study, we examined changes in biological ages in NCBRS to provide insights into the prognosis and health risks of NCBRS. METHODS: We used a publicly available dataset to examine biological aging in NCBRS using DNAm-based epigenetic ages, such as PhenoAge and GrimAge, as well as DNAm-based estimator of telomere length (DNAmTL). We investigated 12 cases, clinically diagnosed as NCBRS, and 27 controls. RESULTS: Compared to controls, NCBRS cases exhibited significantly accelerated PhenoAge and GrimAge as well as significantly shortened DNAmTL. CONCLUSION: These results suggest an acceleration of biological aging in NCBRS and provide insights into the prognosis and health risks of NCBRS.

  Mar. 2022, Molecular genetics & genomic medicine, 10(3) (3), e1876, English, International magazine

  Scientific journal


• Dissecting the Shared Genetic Architecture of Suicide Attempt, Psychiatric Disorders, and Known Risk Factors.

  International Suicide Genetics Consortium

  BACKGROUND: Suicide is a leading cause of death worldwide, and nonfatal suicide attempts, which occur far more frequently, are a major source of disability and social and economic burden. Both have substantial genetic etiology, which is partially shared and partially distinct from that of related psychiatric disorders. METHODS: We conducted a genome-wide association study (GWAS) of 29,782 suicide attempt (SA) cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC). The GWAS of SA was conditioned on psychiatric disorders using GWAS summary statistics via multitrait-based conditional and joint analysis, to remove genetic effects on SA mediated by psychiatric disorders. We investigated the shared and divergent genetic architectures of SA, psychiatric disorders, and other known risk factors. RESULTS: Two loci reached genome-wide significance for SA: the major histocompatibility complex and an intergenic locus on chromosome 7, the latter of which remained associated with SA after conditioning on psychiatric disorders and replicated in an independent cohort from the Million Veteran Program. This locus has been implicated in risk-taking behavior, smoking, and insomnia. SA showed strong genetic correlation with psychiatric disorders, particularly major depression, and also with smoking, pain, risk-taking behavior, sleep disturbances, lower educational attainment, reproductive traits, lower socioeconomic status, and poorer general health. After conditioning on psychiatric disorders, the genetic correlations between SA and psychiatric disorders decreased, whereas those with nonpsychiatric traits remained largely unchanged. CONCLUSIONS: Our results identify a risk locus that contributes more strongly to SA than other phenotypes and suggest a shared underlying biology between SA and known risk factors that is not mediated by psychiatric disorders.

  Feb. 2022, Biological Psychiatry, 91(3) (3), 313 - 327, English, International magazine

  [Refereed]

  Scientific journal


• Epigenetic clock analysis and increased plasminogen activator inhibitor-1 in high-functioning autism spectrum disorder.

  Satoshi Okazaki, Ryo Kimura, Ikuo Otsuka, Yasuko Funabiki, Toshiya Murai, Akitoyo Hishimoto

  BACKGROUND: Autism spectrum disorder (ASD) is characterized by impaired social communication and behavioral problems. An increased risk of premature mortality has been observed in individuals with ASD. Therefore, we hypothesized that biological aging is accelerated in individuals with ASD. Recently, several studies have established genome-wide DNA methylation (DNAm) profiles as 'epigenetic clocks' that can estimate biological aging. In addition, ASD has been associated with differential DNAm patterns. METHODS: We used two independent datasets from blood samples consisting of adult patients with high-functioning ASD and controls: the 1st cohort (38 ASD cases and 31 controls) and the 2nd cohort (6 ASD cases and 10 controls). We explored well-studied epigenetic clocks such as HorvathAge, HannumAge, SkinBloodAge, PhenoAge, GrimAge, and DNAm-based telomere length (DNAmTL). In addition, we investigated seven DNAm-based age-related plasma proteins, including plasminogen activator inhibitor-1 (PAI-1), and smoking status, which are the components of GrimAge. RESULTS: Compared to controls, individuals with ASD in the 1st cohort, but not in the 2nd cohort, exhibited a trend for increased GrimAge acceleration and a significant increase of PAI-1 levels. A meta-analysis showed significantly increased PAI-1 levels in individuals with ASD compared to controls. CONCLUSION: Our findings suggest there is no epigenetic age acceleration in the blood of individuals with ASD. However, this study provides novel evidence regarding increased plasma PAI-1 levels in individuals with high-functioning ASD. These findings suggest PAI-1 may be a biomarker for high-functioning ASD, however, larger studies based on epigenetic clocks and PAI-1 will be necessary to confirm these findings.

  2022, PloS one, 17(2) (2), e0263478, English, International magazine

  Scientific journal


• Polymorphisms in the hypoxia inducible factor binding site of the macrophage migration inhibitory factor gene promoter in schizophrenia.

  Satoshi Okazaki, Shuken Boku, Yuichiro Watanabe, Ikuo Otsuka, Tadasu Horai, Ryo Morikawa, Atsushi Kimura, Naofumi Shimmyo, Takaki Tanifuji, Toshiyuki Someya, Akitoyo Hishimoto

  BACKGROUND: Macrophage migration inhibitory factor (MIF) is a multifunctional cytokine that promotes neurogenesis and neuroprotection. MIF is predominantly expressed in astrocytes in the brain. The serum MIF level and microsatellites/single nucleotide polymorphisms (SNPs) in the MIF gene promoter region are known to be associated with schizophrenia (SCZ). Interestingly, previous studies reported that hypoxia, an environmental risk factor for SCZ, induced MIF expression through binding of the hypoxia inducible factor (HIF)-1 to the hypoxia response element (HRE) in the MIF promoter. METHODS: We investigated the involvement of MIF in SCZ while focusing on the HIF pathway. First, we conducted an association study of the SNP rs17004038 (C>A) in the HRE of the MIF promoter between 1758 patients with SCZ and 1507 controls. Next, we investigated the effect of hypoxia on MIF expression in primary cultured astrocytes derived from neonatal mice forebrain. RESULTS: SNP rs17004038 was significantly associated with SCZ (p = 0.0424, odds ratio = 1.445), indicating that this SNP in the HRE of the MIF promoter was a genetic risk factor for SCZ. Hypoxia induced MIF mRNA expression and MIF protein production and increased HIF-1 binding to the MIF promoter, while the activity of the MIF promoter was suppressed by mutations in the HRE and by deletion of the HRE in astrocytes. CONCLUSION: These results suggest that SNP rs17004038 in the HRE of the MIF promoter was significantly associated with SCZ and may be involved in the pathophysiology of SCZ via suppression of hypoxia and HIF pathway-induced MIF expression.

  2022, PloS one, 17(3) (3), e0265738, English, International magazine

  Scientific journal


• Serum levels of glial cell line-derived neurotrophic factor as a biomarker for mood disorders and lithium response.

  Keita Idemoto, Tomihisa Niitsu, Tatsuki Hata, Tamaki Ishima, Sumiko Yoshida, Kotaro Hattori, Tadasu Horai, Ikuo Otsuka, Hidenaga Yamamori, Shigenobu Toda, Yosuke Kameno, Kiyomitsu Ota, Yasunori Oda, Atsushi Kimura, Tasuku Hashimoto, Norio Mori, Mitsuru Kikuchi, Yoshio Minabe, Ryota Hashimoto, Akitoyo Hishimoto, Kazuyuki Nakagome, Kenji Hashimoto, Masaomi Iyo

  Glial cell line-derived neurotrophic factor (GDNF) plays an important role in the pathophysiology of neuropsychiatric disorders. We examined serum GDNF levels in bipolar disorder (BD) patients and major depressive disorder (MDD) patients and their association with response to lithium therapy. We used a multicenter (six sites), exploratory, cross-sectional case-control design and recruited 448 subjects: 143 BD patients, 116 MDD patients, and 158 healthy controls (HCs). We evaluated the patients' clinical severity using the Clinical Global Impression (CGI), and responses to lithium therapy using the Alda scale. The serum GDNF levels were significantly decreased in the BD and MDD groups compared to the HCs, with no significant difference between the BD and MDD groups. After adjustment, the serum GDNF levels in the BD and MDD patients in remission or depressive states were decreased compared to the HC values. Lower serum GDNF levels in BD patients were associated with higher CGI and Alda scores (i.e., severe illness and good response to lithium therapy, respectively). Our findings suggest that the serum GDNF level may be a biomarker for both BD and MDD in remission or depressive states. The serum GDNF level may be associated with the lithium response of BD patients.

  Jul. 2021, Psychiatry research, 301, 113967 - 113967, English, International magazine

  Scientific journal


• Clozapine increases macrophage migration inhibitory factor (MIF) expression via increasing histone acetylation of MIF promoter in astrocytes.

  Satoshi Okazaki, Shuken Boku, Ikuo Otsuka, Tadasu Horai, Atsushi Kimura, Naofumi Shimmyo, Naruhisa Yamaki, Akitoyo Hishimoto

  Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine and promotes neurogenesis and neuroprotection in brains. In addition, MIF has been identified as a potential marker of schizophrenia (SCZ). Our recent study also showed that serum MIF level is higher in SCZ and positively correlated with antipsychotic doses, and that MIF promoter polymorphisms are associated with SCZ. Here, we investigated the effects of antipsychotics such as clozapine on MIF expression in primary cultured astrocytes derived from neonatal mouse forebrain. MIF mRNA expression was estimated with quantitative reverse-transcription polymerase chain reaction. MIF protein concentration was measured with enzyme-linked immunosorbent assay. The histone acetylation of MIF promoter was examined with chromatin immunoprecipitation assay. As a result, common antipsychotics, especially clozapine, increased MIF mRNA expression in a dose-dependent manner. Clozapine increased MIF mRNA expression and protein concentration in a time-dependent manner. Moreover, clozapine increased the acetylation of histone H3 at lysine 27 residues (H3K27) in MIF promoter. In conclusion, we provide novel evidence that antipsychotics such as clozapine increases MIF expression via the acetylation of H3K27 in astrocytes, and that MIF may have a potential role for astrocytes in the action mechanisms of antipsychotics.

  Mar. 2021, Journal of psychiatric research, 135, 237 - 242, English, International magazine

  Scientific journal


• Epigenetic Clock Analysis in Children With Fetal Alcohol Spectrum Disorder.

  Satoshi Okazaki, Ikuo Otsuka, Yutaka Shinko, Tadasu Horai, Takashi Hirata, Naruhisa Yamaki, Ichiro Sora, Akitoyo Hishimoto

  BACKGROUND: Fetal alcohol spectrum disorder (FASD) is characterized by severe clinical impairment, considerable social burden, and high mortality and morbidity, which are due to various malformations, sepsis, and cancer. As >50% of deaths from FASD occur during the first year of life, we hypothesized that there is the acceleration of biological aging in FASD. Several recent studies have established genome-wide DNA methylation (DNAm) profiles as "epigenetic clocks" that can estimate biological aging, and FASD has been associated with differential DNAm patterns. Therefore, we tested this hypothesis using epigenetic clocks. METHODS: We investigated 5 DNAm-based measures of epigenetic age (HorvathAge, HannumAge, SkinBloodAge, PhenoAge, and GrimAge) and telomere length (DNAmTL) using 4 independent publicly available DNAm datasets; 2 datasets were derived from buccal epithelium, and the other 2 datasets were derived from peripheral blood. RESULTS: Compared with controls, children with FASD exhibited an acceleration of GrimAge in 1 buccal and 2 blood datasets. No significant difference was found in other DNAm ages and DNAmTL. Meta-analyses showed a significant acceleration of GrimAge in the blood samples but not in the buccal samples. CONCLUSIONS: This study provides novel evidence regarding accelerated epigenetic aging in children with FASD.

  Feb. 2021, Alcoholism, clinical and experimental research, 45(2) (2), 329 - 337, English, International magazine

  Scientific journal


• Platelet-derived growth factor BB: A potential diagnostic blood biomarker for differentiating bipolar disorder from major depressive disorder.

  Keita Idemoto, Tamaki Ishima, Tomihisa Niitsu, Tatsuki Hata, Sumiko Yoshida, Kotaro Hattori, Tadasu Horai, Ikuo Otsuka, Hidenaga Yamamori, Shigenobu Toda, Yosuke Kameno, Kiyomitsu Ota, Yasunori Oda, Atsushi Kimura, Tasuku Hashimoto, Norio Mori, Mitsuru Kikuchi, Yoshio Minabe, Ryota Hashimoto, Akitoyo Hishimoto, Kazuyuki Nakagome, Masaomi Iyo, Kenji Hashimoto

  Bipolar disorder (BD) is frequently misdiagnosed as major depressive disorder (MDD) due to overlapping depressive symptoms. This study investigated whether serum platelet-derived growth factor BB (PDGF-BB) is a differential diagnostic biomarker for BD and MDD. An initial SOMAscan proteomics assay of 1311 proteins in small samples from patients with BD and MDD and healthy controls (HCs) suggested that serum levels of PDGF-BB differed between BD and MDD. We then conducted a two-step, exploratory, cross-sectional, case-control study at our institute and five sites that included a total of 549 participants (157 with BD, 144 with MDD, and 248 HCs). Clinical symptoms were assessed using the Hamilton Depression Rating Scale and the Young Mania Rating Scale. In the initial analysis at our institute, serum PDGF-BB levels in the MDD group (n = 36) were significantly lower than those in the BD (n = 39) and HC groups (n = 36). In the multicenter study, serum PDGF-BB levels in the MDD group were again significantly lower than those in the BD and HC groups, with no significant difference between the BD and HC groups. Treatment with sodium valproate was associated with significantly lower serum PDGF-BB levels in patients with BD. After controlling for confounding factors (sex, age, body mass index, clinical severity, and valproate medication), serum PDGF-BB levels were lower in the MDD group than in the BD group regardless of mood state. Our findings suggest that serum PDGF-BB may be a potential biomarker to differentiate BD and MDD.

  Feb. 2021, Journal of psychiatric research, 134, 48 - 56, English, International magazine

  Scientific journal


• Association of Two Variable Number of Tandem Repeats in the Monoamine Oxidase A Gene Promoter with Schizophrenia.

  Takaki Tanifuji, Satoshi Okazaki, Ikuo Otsuka, Tadasu Horai, Yutaka Shinko, Saehyeon Kim, Ichiro Sora, Akitoyo Hishimoto

  BACKGROUND: Monoamine oxidase-A (MAO-A) decomposes dopamine and serotonin, and decreased MAO-A expression increases monoamine levels and is related to the pathophysiology of schizophrenia. Previous studies have reported that variable number of tandem repeats (VNTR), namely, upstream (u)VNTR, and some single nucleotide polymorphisms (SNPs) in the MAOA gene are associated with schizophrenia. METHODS: We investigated the two VNTRs and their related SNPs (rs6323 and rs1137070) in the MAOA gene promoter in 859 patients with schizophrenia and 826 healthy controls. Distal (d)VNTR and uVNTR were genotyped with fluorescence-based fragment polymerase chain reaction assays, and rs6323 and rs1137070 with TaqMan SNP genotyping assays. RESULTS: Neither the genotype nor allelic frequency of the VNTRs or SNPs showed significant differences between the schizophrenia and control groups. On the other hand, analysis of the dVNTR-uVNTR-rs6323-rs1137070 haplotype showed significant association for nine repeats (9R)-3R-T-C in female patients (corrected p = 0.0006, odds ratio [confidence interval] = 2.17 [1.446-3.257]). CONCLUSION: Our findings provide novel evidence that MAOA gene polymorphisms are associated with an increased risk of developing schizophrenia in females.

  2021, Neuropsychiatric disease and treatment, 17, 3315 - 3323, English, International magazine

  Scientific journal


• miR-19b is elevated in peripheral blood of schizophrenic patients and attenuates proliferation of hippocampal neural progenitor cells.

  Tadasu Horai, Shuken Boku, Satoshi Okazaki, Ikuo Otsuka, Woraphat Ratta-Apha, Kentaro Mouri, Naruhisa Yamaki, Takashi Hirata, Akitoyo Hishimoto

  MicroRNAs (miRNAs) have been investigated in neurodevelopmental and psychiatric disorders including schizophrenia (SZ). Previous studies showed miRNAs dysregulation in postmortem brain tissues and peripheral blood of SZ patients. These suggest that miRNAs may play a role in the pathophysiology of SZ and be a potential biomarker of SZ. Previous studies also showed that miRNAs regulated neurogenesis and that neurogenesis was involved in the pathophysiology of SZ. In addition, a recent study showed that miR-19a and 19b, enriched in neural progenitor cells (NPC) in adult hippocampus, were increased in human NPC derived from induced pluripotent stem cell derived from SZ patients. However, it remains unclear whether the levels of miR-19a and 19b are altered in peripheral blood of SZ patients and how miR-19a and 19b affects neurogenesis. To elucidate them, first we examined the levels of miR-19a and 19b in peripheral blood of SZ patients with quantitative RT-PCR and showed that the level of miR-19b, but not miR-19a, was significantly higher (miR-19a: p = 0.5733, miR-19b: p = 0.0038) in peripheral blood of SZ patients (N = 22) than that of healthy controls (N = 19). Next, we examined the involvement of miR-19b in proliferation and survival of mouse neonatal mice hippocampus-derived NPC with BrdU assay and TUNEL assay. The silencing of miR-19b significantly increased proliferation (N = 5, p = 0.0139), but not survival (N = 5, p = 0.9571), of neonatal mice hippocampus-derived NPC. These results suggest that the level of miR-19b in peripheral blood is a potential biomarker of schizophrenia and that the higher level of miR-19b may increase the vulnerability of SZ via attenuating proliferation of hippocampal NPC.

  Dec. 2020, Journal of psychiatric research, 131, 102 - 107, English, International magazine

  Scientific journal


• Decelerated epigenetic aging associated with mood stabilizers in the blood of patients with bipolar disorder.

  Satoshi Okazaki, Shusuke Numata, Ikuo Otsuka, Tadasu Horai, Makoto Kinoshita, Ichiro Sora, Tetsuro Ohmori, Akitoyo Hishimoto

  There is high mortality among patients with bipolar disorder (BD). Studies have reported accelerated biological aging in patients with BD. Recently, Horvath and Hannum et al. independently developed DNA methylation (DNAm) profiles as "epigenetic clocks," which are the most accurate biological age estimate. This led to the development of two accomplished measures of epigenetic age acceleration (EAA) using blood samples, namely, intrinsic and extrinsic EAA (IEAA and EEAA, respectively). IEAA, which is based on Horvath's clock, is independent of blood cell counts and indicates cell-intrinsic aging. On the other hand, EEAA, which is based on Hannum's clock, is associated with age-dependent changes in blood cell counts and indicates immune system aging. Further, Lu et al. developed the "GrimAge" clock, which can strongly predict the mortality risk, and DNAm-based telomere length (DNAmTL). We used a DNAm dataset from whole blood samples obtained from 30 patients with BD and 30 healthy controls. We investigated Horvath EAA, IEAA, Hannum EAA, EEAA, Grim EAA, DNAmTL, and DNAm-based blood cell composition. Compared with controls, there was a decrease in Horvath EAA and IEAA in patients with BD. Further, there was a significant decrease in Horvath EAA and IEAA in patients with BD taking medication combinations of mood stabilizers (including lithium carbonate, sodium valproate, and carbamazepine) than in those taking no medication/monotherapy. This study provides novel evidence indicating decelerated epigenetic aging associated with mood stabilizers in patients with BD.

  May 2020, Translational psychiatry, 10(1) (1), 129 - 129, English, International magazine

  Scientific journal


• ATP and repetitive electric stimulation increases leukemia inhibitory factor expression in astrocytes: A potential role for astrocytes in the action mechanism of electroconvulsive therapy.

  Soichiro Maruyama, Shuken Boku, Satoshi Okazaki, Hiroki Kikuyama, Yoshito Mizoguchi, Akira Monji, Ikuo Otsuka, Ichiro Sora, Tetsufumi Kanazawa, Akitoyo Hishimoto, Hiroshi Yoneda

  AIM: Electroconvulsive therapy (ECT) is effective for psychiatric disorders. However, its action mechanism remains unclear. We previously reported that transcription factor 7 (TCF7) was increased in patients successfully treated with ECT. TCF7 regulates Wnt pathway, which regulates adult hippocampal neurogenesis. Adult hippocampal neurogenesis is involved in the pathophysiology of psychiatric disorders. Astrocytes play a role in adult hippocampal neurogenesis via neurogenic factors. Of astrocyte-derived neurogenic factors, leukemia inhibitory factor (LIF) and fibroblast growth factor 2 (FGF2) activate Wnt pathway. In addition, adenosine triphosphate (ATP), released from excited neurons, activates astrocytes. Therefore, we hypothesized that ECT might increase LIF and/or FGF2 in astrocytes. To test this, we investigated the effects of ATP and electric stimulation (ES) on LIF and FGF2 expressions in astrocytes. METHODS: Astrocytes were derived from neonatal mouse forebrain and administered ATP and ES. The mRNA expression was estimated with quantitative reverse-transcription polymerase chain reaction. Protein concentration was measured with ELISA. RESULTS: ATP increased LIF, but not FGF2, expression. Multiple ES, but not single, increased LIF expression. Knockdown of P2X2 receptor (P2X2R) attenuated ATP-induced increase of LIF mRNA expression. In contrast, P2X3 and P2X4 receptors intensified it. CONCLUSION: P2X2R may mediate ATP-induced LIF expression in astrocytes and multiple ES directly increases LIF expression in astrocytes. Therefore, both ATP/P2X2R and multiple ES-induced increases of LIF expression in astrocytes might mediate the efficacy of ECT on psychiatric disorders. Elucidating detailed mechanisms of ATP/P2X2R and multiple ES-induced LIF expression is expected to result in the identification of new therapeutic targets for psychiatric disorders.

  May 2020, Psychiatry and clinical neurosciences, 74(5) (5), 311 - 317, English, International magazine

  Scientific journal


• Whole-exome sequencing in a family with a monozygotic twin pair concordant for schizophrenia and a follow-up case-control study of identified de-novo variants.

  Satoshi Hoya, Yuichiro Watanabe, Ayako Nunokawa, Ikuo Otsuka, Masako Shibuya, Hirofumi Igeta, Akitoyo Hishimoto, Toshiyuki Someya

  Whole-exome sequencing (WES) studies have shown that de-novo variants contribute to the genetic etiology of schizophrenia. WES studies of families with a monozygotic twin pair concordant or discordant for a disease may be fruitful for identifying de-novo pathogenic variants. Here, we performed WES in six individuals from one family (affected monozygotic twins, their unaffected parents, and two siblings) and identified three de-novo missense variants (CPT2 Ala283Thr, CPSF3 Val584Ile, and RNF148 Val210Ile) in the monozygotic twin pair concordant for schizophrenia. These three missense variants were not found in 1760 patients with schizophrenia or schizoaffective disorder or 1508 healthy controls. Our data do not support the role of the three missense variants in conferring risk for schizophrenia.

  Apr. 2020, Psychiatric genetics, 30(2) (2), 60 - 63, English, International magazine

  Scientific journal


• Accelerated extrinsic epigenetic aging and increased natural killer cells in blood of suicide completers.

  Okazaki S, Otsuka I, Horai T, Hirata T, Takahashi M, Ueno Y, Boku S, Sora I, Hishimoto A.

  BACKGROUND: Studies suggest aberrant DNA methylation in victims of suicide. Recently, DNA methylation profiles have been developed for determining "epigenetic age," which is the most accurate estimate of biological age. Subsequently, two refined measures of epigenetic age acceleration have been expanded for blood samples as intrinsic and extrinsic epigenetic age acceleration (IEAA and EEAA, respectively). IEAA involves pure epigenetic aging independent of blood cell composition, whereas EEAA involves immunosenescence in association with blood cell composition. METHODS: We investigated epigenetic age acceleration using two independent DNA methylation datasets: a brain dataset from 16 suicide completers and 15 non-psychiatric controls and a blood dataset compiled using economical DNA pooling technique from 56 suicide completers and 60 living healthy controls. In the blood dataset, we considered IEAA and EEAA, as well as DNA methylation-based blood cell composition. RESULTS: There was no significant difference in universal epigenetic age acceleration between suicide completers and controls in both brain and blood datasets. Blood of suicide completers exhibited an increase in EEAA, but not in IEAA. We additionally found that suicide completers had more natural killer cells but fewer granulocytes compared to controls. CONCLUSION: This study provides novel evidence for accelerated extrinsic epigenetic aging in suicide completers and for the potential application of natural killer cells as a biomarker for suicidal behavior.

  Mar. 2020, Progress in Neuro-Psychopharmacology & Biological Psychiatry, 98, 109805 - 109805, English, International magazine

  [Refereed]

  Scientific journal


• Chemokine alterations in the postmortem brains of suicide completers.

  Yutaka Shinko, Ikuo Otsuka, Satoshi Okazaki, Tadasu Horai, Shuken Boku, Motonori Takahashi, Yasuhiro Ueno, Ichiro Sora, Akitoyo Hishimoto

  Suicide is a major health problem in the modern world. However, its physiological mechanisms have not been well elucidated yet. Immunological disturbances have been reported in psychiatric disorders such as major depressive disorder (MDD), bipolar disorder (BP), and schizophrenia. Some studies have also suggested an association between immunological alterations especially neuroinflammation, and suicide. Chemokines play important roles in inflammation, and studies investigating chemokines in psychiatric diseases such as schizophrenia, MDD, and BP have reported chemokine dysregulations. However, there have been very few studies on the association between chemokines and suicide. We studied chemokine alterations in the postmortem brains of suicide completers and compared them to those of controls. We obtained brain tissue samples of the dorsolateral prefrontal cortex from 16 suicide completers and 23 controls. We examined the concentrations of chemokines and related substances in the brain tissue from these two groups using the Bio-Plex Pro™ Human Chemokine Panel 40-Plex. We performed multiple regression analysis with covariates. The levels of CCL1, CCL8, CCL13, CCL15, CCL17, CCL19, CCL20, CXCL11, and IL-10 were significantly decreased, whereas the IL-16 levels were significantly increased in the suicide completers after adjustment with the Benjamini-Hochberg method to control for type Ⅰ errors (Q < 0.05). The observed chemokine alterations might suggest the presence of suicide-specific immunological mechanisms.

  Jan. 2020, Journal of psychiatric research, 120, 29 - 33, English, International magazine

  Scientific journal


• Genome-wide association studies identify polygenic effects for completed suicide in the Japanese population.

  Otsuka I, Akiyama M, Shirakawa O, Okazaki S, Momozawa Y, Kamatani Y, Izumi T, Numata S, Takahashi M, Boku S, Sora I, Yamamoto K, Ueno Y, Toda T, Kubo M, Hishimoto A.

  Suicide is a significant public health problem worldwide, and several Asian countries including Japan have relatively high suicide rates on a world scale. Twin, family, and adoption studies have suggested high heritability for suicide, but genetics lags behind due to difficulty in obtaining samples from individuals who died by suicide, especially in non-European populations. In this study, we carried out genome-wide association studies combining two independent datasets totaling 746 suicides and 14,049 non-suicide controls in the Japanese population. Although we identified no genome-wide significant single-nucleotide polymorphisms (SNPs), we demonstrated significant SNP-based heritability (35-48%; P < 0.001) for completed suicide by genomic restricted maximum-likelihood analysis and a shared genetic risk between two datasets (Pbest = 2.7 × 10-13) by polygenic risk score analysis. This study is the first genome-wide association study for suicidal behavior in an East Asian population, and our results provided the evidence of polygenic architecture underlying completed suicide.

  Lead, Nov. 2019, Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 44(12) (12), 2119 - 2124, English, International magazine

  [Refereed]

  Scientific journal


• Major depressive disorder-associated SIRT1 locus affects the risk for suicide in women after middle age.

  Takashi Hirata, Ikuo Otsuka, Satoshi Okazaki, Kentaro Mouri, Tadasu Horai, Shuken Boku, Motonori Takahashi, Yasuhiro Ueno, Ichiro Sora, Osamu Shirakawa, Akitoyo Hishimoto

  A recent genome-wide association study (GWAS) for major depressive disorder (MDD) in Chinese women identified a single-nucleotide polymorphism (SNP), rs12415800, near the Sirtuin1 (SIRT1) gene as one of the top candidate loci. However, no study has shown a genetic association between SIRT1 and completed suicide, which is one of the most serious outcomes of MDD. In this study, 778 suicide completers and 760 controls in a Japanese population were genotyped for two SNPs in strong linkage disequilibrium (rs12415800 and rs4746720 in 3'UTR). We found significant associations between both SNPs and completed suicide among women aged ≥50 years. Additional analysis using postmortem brain tissues (10 suicide brains and 13 non-suicide brains) revealed the following: while SIRT1 gene expression in the prefrontal cortex did not differ between suicide and non-suicide brains, DNAJC12 gene expression, potentially implicated by the SNPs genotyped here, was significantly decreased in suicide brains (p = 0.003). In conclusion, regarding the genetic association of SIRT1 with MDD that was previously identified in women by the Chinese GWAS, we successfully validated our results using a female suicidal cohort in the same Asian population with the same direction of allelic effect.

  Aug. 2019, Psychiatry research, 278, 141 - 145, English, International magazine

  Scientific journal


• Epigenetic clock analysis of blood samples from Japanese schizophrenia patients.

  Satoshi Okazaki, Ikuo Otsuka, Shusuke Numata, Tadasu Horai, Kentaro Mouri, Shuken Boku, Tetsuro Ohmori, Ichiro Sora, Akitoyo Hishimoto

  The accelerated aging hypothesis of schizophrenia (SCZ) has been proposed. DNA methylation profiles were developed for determining "epigenetic age." Here, we assessed intrinsic and extrinsic epigenetic age acceleration (IEAA and EEAA, respectively) in SCZ. We examined two independent cohorts of Japanese ancestry. The first cohort consisted of 80 patients with SCZ under long-term or repeated hospitalization and 40 controls, with the economical DNA pooling technique. The second cohort consisted of 24 medication-free patients with SCZ and 23 controls. Blood of SCZ subjects exhibited decreased EEAA in the first cohort (p = 0.0162), but not in the second cohort. IEAA did not differ in either cohort. We performed replication analyses using publicly available datasets from European ancestry (three blood and one brain datasets). One blood dataset showed increased EEAA in SCZ (p = 0.0228). Overall, our results provide evidence for decreased EEAA in SCZ associated with hospitalization in the Japanese population.

  Feb. 2019, NPJ schizophrenia, 5(1) (1), 4 - 4, English, International magazine

  Scientific journal


• Mitochondrial DNA Copy Number Raises the Potential of Left Frontopolar Hemodynamic Response as a Diagnostic Marker for Distinguishing Bipolar Disorder From Major Depressive Disorder.

  Noa Tsujii, Ikuo Otsuka, Satoshi Okazaki, Masaya Yanagi, Shusuke Numata, Naruhisa Yamaki, Yoshihiro Kawakubo, Osamu Shirakawa, Akitoyo Hishimoto

  Background: Given a lack of markers, diagnoses of bipolar disorder (BD) and major depressive disorder (MDD) rely on clinical assessment of symptoms. However, the depressive mood states of BD and depressive symptoms of MDD are often difficult to distinguish, which leads to misdiagnoses, which in turn leads to inadequate treatment. Previous studies have shown that the hemodynamic responses of the left frontopolar cortex measured by near-infrared spectroscopy (NIRS) differ between BD and MDD; these hemodynamic responses are associated with altered mitochondrial metabolism; and mitochondrial DNA copy number (mtDNAcn), an index of mitochondrial dysfunction, tends to decrease in BD and increase in MDD patients. In this study, we confirmed that mtDNAcn trends in opposite directions in BD and MDD. We then determined whether mtDNAcn could enhance the utility of NIRS as a diagnostic marker to distinguish between BD and MDD. Methods: We determined mtDNAcn in peripheral blood samples from 58 healthy controls, 79 patients with BD, and 44 patients with MDD. Regional hemodynamic responses during a verbal fluency task (VFT) in 24 BD patients and 44 MDD patients, matched by age and depression severity, were monitored using NIRS. Results: Measurements of mtDNAcn were lower in BD patients and higher in MDD patients than in controls. The left frontopolar region exhibited the most significant differences in mean VFT-related oxy-Hb changes between the BD and MDD groups. Multivariate logistic regression analysis with variables including age, sex, hemodynamic response of the left frontopolar region, and mtDNAcn showed high accuracy for distinguishing BD from MDD (area under the curve = 0.917; 95% confidence interval = 0.849-0.985). For the BD group, we observed a positive correlation between hemodynamic responses in the left frontopolar region and mtDNAcn, while for the MDD group, we observed a negative correlation. Conclusions: Our findings suggest that the association between hemodynamic response and mitochondrial dysfunction in BD or MDD plays an important role in differentiating the pathophysiological mechanisms of BD from those of MDD.

  2019, Frontiers in psychiatry, 10, 312 - 312, English, International magazine

  Scientific journal


• Rare compound heterozygous missense SPATA7 variations and risk of schizophrenia; whole-exome sequencing in a consanguineous family with affected siblings, follow-up sequencing and a case-control study.

  Hirofumi Igeta, Yuichiro Watanabe, Ryo Morikawa, Masashi Ikeda, Ikuo Otsuka, Satoshi Hoya, Masataka Koizumi, Jun Egawa, Akitoyo Hishimoto, Nakao Iwata, Toshiyuki Someya

  PURPOSE: Whole-exome sequencing (WES) of multiplex families is a promising strategy for identifying causative variations for common diseases. To identify rare recessive risk variations for schizophrenia, we performed a WES study in a consanguineous family with affected siblings. We then performed follow-up sequencing of SPATA7 in schizophrenia-affected families. In addition, we performed a case-control study to investigate association between SPATA7 variations and schizophrenia. PATIENTS AND METHODS: WES was performed on two affected siblings and their unaffected parents, who were second cousins, of a multiplex schizophrenia family. Subsequently, we sequenced the coding region of SPATA7, a potential risk gene identified by the WES analysis, in 142 affected offspring from 137 families for whom parental DNA samples were available. We further tested rare recessive SPATA7 variations, identified by WES and sequencing, for associations with schizophrenia in 2,756 patients and 2,646 controls. RESULTS: Our WES analysis identified rare compound heterozygous missense SPATA7 variations, p.Asp134Gly and p.Ile332Thr, in both affected siblings. Sequencing SPATA7 coding regions from 137 families identified no rare recessive variations in affected offspring. In the case-control study, we did not detect the rare compound heterozygous SPATA7 missense variations in patients or controls. CONCLUSION: Our data does not support the role of the rare compound heterozygous SPATA7 missense variations p.Asp134Gly and p.Ile332Thr in conferring a substantial risk of schizophrenia.

  2019, Neuropsychiatric disease and treatment, 15, 2353 - 2363, English, International magazine

  Scientific journal


• Mitochondrial DNA copy number of peripheral blood in bipolar disorder: The present study and a meta-analysis.

  Naruhisa Yamaki, Ikuo Otsuka, Shusuke Numata, Masaya Yanagi, Kentaro Mouri, Satoshi Okazaki, Shuken Boku, Tadasu Horai, Tetsuro Ohmori, Osamu Shirakawa, Ichiro Sora, Akitoyo Hishimoto

  Numerous evidence indicated mitochondrial abnormalities in the pathophysiology of bipolar disorder (BD); however, it remains unclear whether aberrant mitochondrial DNA (mtDNA) copy number (cn) occur in BD due to the conflicting results in previous studies. Here, peripheral blood mtDNAcn in 69 BD patients and 54 controls were analysed via qPCR. BD patients had significantly lower mtDNAcn compared to controls (regardless of their BD type [BD I or II]). Meta-analysis for all previous BD-mtDNAcn studies combining our results with previously published studies failed to identify any significant association. Meanwhile, Asian-specific meta-analysis remarkably revealed lower mtDNAcn in BD patients.

  Nov. 2018, Psychiatry research, 269, 115 - 117, English, International magazine

  Scientific journal


• Longer telomeres in elderly schizophrenia are associated with long-term hospitalization in the Japanese population.

  Yuan Zhang, Akitoyo Hishimoto, Ikuo Otsuka, Yuichiro Watanabe, Shusuke Numata, Hidenaga Yamamori, Shuken Boku, Tadasu Horai, Toshiyuki Someya, Tetsuro Ohmori, Ryota Hashimoto, Ichiro Sora

  Several previous studies have investigated an association between leukocyte telomere length (LTL) and schizophrenia (SCZ). However, results have been largely inconsistent, partially due to the relatively small sample sizes in each study and heterogeneity caused by various uncontrolled confounders (e.g., duration of illness or hospitalization, lifetime antipsychotic dose, and LTL assay methods). Here, we investigate the association of LTL with SCZ with the quantitative polymerase chain reaction method in independent cohorts consisting of 1241 patients with SCZ and 1042 controls (the largest independent sample in this field). Furthermore, we examined whether duration of hospitalization and lifetime antipsychotic dose had an effect on LTL in SCZ. In all samples, we observed significantly longer LTL in patients with SCZ relative to controls. In subgroup analyses, we observed that longer telomeres in SCZ were only visible in elderly patients and not in patients under 50 years old. Moreover, significantly longer LTL in elderly patients with SCZ was only specific to those with long-term hospitalization, but not outpatients or those with short-term hospitalization. This may be because the former received more appropriate lifestyle management. Meanwhile, lifetime antipsychotic dose had no effect on LTL. Our findings suggest that consideration of the effect of age and duration of hospitalization on LTL may improve our understanding of controversial results obtained in previous studies of telomeres in SCZ.

  Aug. 2018, Journal of psychiatric research, 103, 161 - 166, English, International magazine

  Scientific journal


• Increased serum levels and promoter polymorphisms of macrophage migration inhibitory factor in schizophrenia.

  Satoshi Okazaki, Akitoyo Hishimoto, Ikuo Otsuka, Yuichiro Watanabe, Shusuke Numata, Shuken Boku, Naofumi Shimmyo, Makoto Kinoshita, Emiko Inoue, Tetsuro Ohmori, Toshiyuki Someya, Ichiro Sora

  BACKGROUND: Numerous studies have suggested that an immune system imbalance plays an important role in schizophrenia. Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine. It plays multiple roles in various biological processes, including inflammation and neurogenesis. Furthermore, several exhaustive serum proteomic profiling studies have identified MIF as a potential biomarker of schizophrenia. Here, we investigate MIF protein levels in serum and postmortem prefrontal cortex in patients with schizophrenia and controls. Moreover, we investigate the association of two functional polymorphisms in the MIF gene promoter region (MIF-794CATT5-8 microsatellite and MIF-173G/C single-nucleotide polymorphism [SNP]) with schizophrenia. METHODS: We measured serum MIF levels with an enzyme-linked immunosorbent assay (ELISA) (51 patients vs. 86 controls) and postmortem brain MIF levels with a western blotting assay (18 patients vs. 22 controls). Subsequently, we genotyped the MIF-794CATT5-8 microsatellite with a fluorescence-based fragment assay and the MIF-173G/C SNP with a TaqMan SNP genotyping assay (1483 patients vs. 1454 controls). RESULTS: Serum MIF levels were significantly higher in patients with schizophrenia than in controls (p=0.00118), and were positively correlated with antipsychotic dose (Spearman's r=0.222, p=0.0402). In addition, an earlier age of onset was observed in patients with a high serum MIF level (≥40ng/mL) than those with a low serum MIF level (<40ng/mL) (p=0.0392). However, postmortem brain MIF levels did not differ between patients with schizophrenia and controls. The association study revealed that the CATT6-G haplotype was nominally significantly associated with schizophrenia (p=0.0338), and that the CATT6 allele and CATT6-G haplotype were significantly associated with female adolescent-onset schizophrenia (AsOS) (corrected p=0.0222 and p=0.0147, respectively). CONCLUSIONS: These results suggest that serum MIF level is a potential pharmacodynamic and/or monitoring marker of schizophrenia, and is related to a novel antipsychotic effect beyond dopamine antagonism. Furthermore, the MIF gene polymorphisms are associated with the risk for schizophrenia especially in adolescent females, and are potential stratification markers of schizophrenia. Further studies of MIF are warranted to elucidate the pathophysiology of schizophrenia and the effects of antipsychotics.

  Apr. 2018, Progress in neuro-psychopharmacology & biological psychiatry, 83, 33 - 41, English, International magazine

  Scientific journal


• Loss of chromosome Y in blood, but not in brain, of suicide completers.

  Atsushi Kimura, Akitoyo Hishimoto, Ikuo Otsuka, Satoshi Okazaki, Shuken Boku, Tadasu Horai, Takeshi Izumi, Motonori Takahashi, Yasuhiro Ueno, Osamu Shirakawa, Ichiro Sora

  Men have a higher rate of completed suicide than women, which suggests that sex chromosome abnormalities may be related to the pathophysiology of suicide. Recent studies have found an aberrant loss of chromosome Y (LOY) in various diseases; however, no study has investigated whether there is an association between LOY and suicide. The purpose of this study was to determine whether LOY occurs in men who completed suicide. Our study consisted of 286 male Japanese subjects comprised of 140 suicide completers without severe physical illness (130 post-mortem samples of peripheral blood and 10 brains) and 146 age-matched control subjects (130 peripheral blood samples from healthy individuals and 16 post-mortem brains). LOY was measured as the chromosome Y/chromosome X ratio of the fluorescent signal of co-amplified short sequences from the Y-X homologous amelogenin genes (AMELY and AMELX). Regression analyses showed that LOY in the blood of suicide completers was significantly more frequent than that found in controls (odds ratio = 3.50, 95% confidence interval = 1.21-10.10), but not in the dorsolateral prefrontal cortex (DLPFC) region of brain. Normal age-dependent LOY in blood was found in healthy controls (r = -0.353, p < 0.001), which was not seen in suicide completers (r = -0.119, p = 0.177). DLPFC tissue had age-dependent LOY (B = -0.002, p = 0.015), which was independent of phenotype. To our knowledge, this is the first study demonstrating that LOY in blood is associated with suicide completion. In addition, our findings are the first to also indicate that age-dependent LOY may occur not only in blood, but also in specific brain regions.

  2018, PloS one, 13(1) (1), e0190667, English, International magazine

  Scientific journal


• A cross-sectional study exploring useful indicators for low bone mineral density in male alcoholic patients.

  Tadasu Horai, Akitoyo Hishimoto, Ikuo Otsuka, Tatsuhiro So, Kentaro Mouri, Naofumi Shimmyo, Shuken Boku, Noriaki Okishio, Ichiro Sora

  BACKGROUND: Alcohol dependence induces low bone mineral density (BMD), predicting osteoporosis, while low and moderate alcohol consumption may even increase BMD. In recent years, undercarboxylated osteocalcin (ucOC) and tartrate-resistant acid phosphatase-5b (TRACP-5b), bone turnover markers, have gained special interest as useful indicators of low BMD. However, it remains unclear whether other alcohol-related variables (eg, duration of abstinence and continuous drinking) are linked to aberrant BMD. In addition, no previous study has investigated whether ucOC or TRACP-5b is clinically useful to predict low BMD not only in the general population, but also in alcohol-dependent subjects. PATIENTS AND METHODS: We recruited 275 male alcohol-dependent subjects and collected information about their drinking habits, comorbid diseases, smoking history and walking exercise behavior. BMD in each subject was determined by ultrasonography. Serum liver enzymes (AST, ALT, ALP, ChE, γ-GTP and LDH), ucOC and TRACP-5b were measured in all subjects. T-scores were calculated according to BMD for all subjects. RESULTS: The mean T-scores of our subjects were negatively shifted compared to the general population (-0.75±1.36 SD). We divided our subjects into a normal BMD group (n=137) and a low BMD group (n=138) according to their T-scores (T-score ≥-1 SD, normal BMD; T-score <-1 SD, low BMD). Multivariate logistic regression analysis showed that body mass index (BMI) was negatively associated with low BMD (95% CI: 0.75-0.90). By contrast, long abstinence period (95% CI: 1.40-4.21), smoking (95% CI: 1.30-5.56), hypertension (95% CI: 1.04-3.76), lactate dehydrogenase (LDH) (95% CI: 1.00-1.01) and ucOC (95% CI: 1.04-1.22) were positively associated with low BMD. CONCLUSION: In alcohol-dependent males, smoking habits and higher ucOC are associated with low BMD. Our study suggests that smoking cessation may prevent lower BMD, and ucOC may predict lower BMD in alcohol-dependent individuals.

  2018, Neuropsychiatric disease and treatment, 14, 663 - 669, English, International magazine

  Scientific journal


• Investigation of chromosome Y loss in men with schizophrenia.

  Takashi Hirata, Akitoyo Hishimoto, Ikuo Otsuka, Satoshi Okazaki, Shuken Boku, Atsushi Kimura, Tadasu Horai, Ichiro Sora

  BACKGROUND: Life expectancy is 10-20 years lower in patients with schizophrenia than in the general population. In addition, men with schizophrenia have an earlier age at onset, more pronounced deficit symptoms, poorer course, and poorer response to antipsychotic medications than women. Recent studies have indicated that loss of chromosome Y (LOY) in peripheral blood is associated with an increased risk of all-cause mortality. In order to elucidate the pathophysiology of male-specific features, we investigated the association between LOY and schizophrenia. MATERIALS AND METHODS: The present study included 360 Japanese men (146 patients with schizophrenia vs 214 controls). The relative amount of Y chromosome was defined as the ratio of chromosome Y to chromosome X (Y/X ratio) based on the fluorescent signal of co-amplified short sequences from the Y-X homologous amelogenin genes (AMELY and AMELX). RESULTS: There was no significant difference in the frequency of LOY between the schizophrenia and control groups. However, longer duration of illness was associated with LOY after controlling for age and smoking status in the schizophrenia group (P=0.007, OR =1.11 [95% CI =1.03-1.19]). CONCLUSION: According to our results, schizophrenia may not have a remarkable effect on blood LOY; however, LOY may be associated with disease course in patients with schizophrenia.

  2018, Neuropsychiatric disease and treatment, 14, 2115 - 2122, English, International magazine

  Scientific journal


• Association of CYP2D6 polymorphisms and extrapyramidal symptoms in schizophrenia patients receiving risperidone: a retrospective study.

  Takahiro Ito, Kazuhiro Yamamoto, Fuminori Ohsawa, Ikuo Otsuka, Akitoyo Hishimoto, Ichiro Sora, Midori Hirai, Ikuko Yano

  BACKGROUND: Risperidone is mainly metabolized by cytochrome P450 (CYP) 2D6 in the liver. The gene encoding CYP2D6 is highly polymorphic. The average steady-state plasma concentration of risperidone active moiety is higher in the CYP2D6 intermediate metabolizers (IMs) compared with that in the extensive metabolizers (EMs). An association between drug-induced extrapyramidal symptoms scale (DIEPSS) score and CYP2D6 polymorphisms has not been reported to date. This study investigates the association of CYP2D6 polymorphisms with the severity of extrapyramidal symptoms in schizophrenia patients receiving risperidone therapy. METHODS: Schizophrenia patients undergoing risperidone treatment were recruited for the study in the Kobe University Hospital. We evaluated extrapyramidal symptoms of schizophrenia using the DIEPSS. CYP2D6*10 and CYP2D6*14 were analyzed using TaqMan® assays, and CYP2D6*5 was analyzed using the long-PCR method. Patients with CYP2D6*1/*5, *1/*14, *5/*10, *10/*10, and *10/*14 were classified as IMs, and patients with CYP2D6*1/*1 and *1/*10 were classified as EMs. Patients with CYP2D6*5/*5, *5/*14, and *14/*14 were classified as poor metabolizers (PMs). RESULTS: A total of 22 patients were included in the study. No patients were classified as PMs. The dose of risperidone (mg/day) was not significantly different between EMs (n = 15) and IMs (n = 7) (median with the interquartile range: 4.0 (2.0-6.0) vs. 4.0 (2.0-7.0) mg, p = 0.31). The age and disease duration of schizophrenia were not significantly different between the EMs and IMs. The DIEPSS score in the IMs was significantly higher than that in the EMs (median with the interquartile range: 5.0 (3.5-6.5) vs. 0.0 (0.0-3.0), p < 0.001). The multiple regression analysis showed that CYP2D6 IMs is a significant risk factor for the DIEPSS (p < 0.05). CONCLUSION: Special attentions should be paid to the onset of extrapyramidal symptoms in schizophrenia patients identified as CYP2D6 IM undergoing risperidone therapy.

  2018, Journal of pharmaceutical health care and sciences, 4, 28 - 28, English, International magazine

  Scientific journal


• Rare PDCD11 variations are not associated with risk of schizophrenia in Japan.

  Satoshi Hoya, Yuichiro Watanabe, Akitoyo Hishimoto, Ayako Nunokawa, Naoshi Kaneko, Tatsuyuki Muratake, Naofumi Shinmyo, Ikuo Otsuka, Shujiro Okuda, Emiko Inoue, Hirofumi Igeta, Masako Shibuya, Jun Egawa, Naoki Orime, Ichiro Sora, Toshiyuki Someya

  AIM: Rare gene variations are thought to confer substantial risk for schizophrenia. We performed a three-stage study to identify rare variations that have a strong impact on the risk of developing schizophrenia. METHODS: In the first stage, we prioritized rare missense variations using whole-exome sequencing (WES) data from three families, consisting of a proband, an affected sibling, and parents. In the second stage, we performed targeted resequencing of the PDCD11 coding region in 96 patients. In the third stage, we conducted an association study of rare PDCD11 variations with schizophrenia in a total of 1357 patients and 1394 controls. RESULTS: Via WES, we identified two rare missense PDCD11 variations, p.(Asp961Asn) and p.(Val1240Leu), shared by two affected siblings within families. Targeted resequencing of the PDCD11 coding region identified three rare non-synonymous variations: p.(Asp961Asn), p.(Phe1835del), and p.(Arg1837His). The case-control study demonstrated no significant associations between schizophrenia and four rare PDCD11 variations: p.(Asp961Asn), p.(Val1240Leu), p.(Phe1835del), and p.(Arg1837His). CONCLUSION: Our data do not support the role of rare PDCD11 variations in conferring substantial risk for schizophrenia in the Japanese population.

  Nov. 2017, Psychiatry and clinical neurosciences, 71(11) (11), 780 - 788, English, International magazine

  Scientific journal


• Rare FBXO18 variations and risk of schizophrenia: Whole-exome sequencing in two parent-affected offspring trios followed by resequencing and case-control studies.

  Satoshi Hoya, Yuichiro Watanabe, Akitoyo Hishimoto, Ayako Nunokawa, Emiko Inoue, Hirofumi Igeta, Ikuo Otsuka, Masako Shibuya, Jun Egawa, Ichiro Sora, Toshiyuki Someya

  AIM: Rare variations are suggested to play a role in the genetic etiology of schizophrenia; to further investigate their role, we performed a three-stage study in a Japanese population. METHODS: In the first stage, we performed whole-exome sequencing (WES) of two parent-affected offspring trios. In the second stage, we resequenced the FBXO18 coding region in 96 patients. In the third stage, we tested rare non-synonymous FBXO18 variations for association with schizophrenia in two independent populations comprising a total of 1376 patients and 1496 controls. RESULTS: A rare frameshift variation (L116fsX) in the FBXO18 gene was recurrently identified by WES in both trios. Resequencing FBXO18 coding regions, we detected three rare non-synonymous variations (V15L, L116fsX, and V1006I). However, there were no significant associations between these rare FBXO18 variations and schizophrenia in the case-control study. CONCLUSION: Our present study does not provide evidence for the contribution of rare non-synonymous FBXO18 variations to the genetic etiology of schizophrenia in the Japanese population. However, to draw a definitive conclusion, further studies should be performed using sufficiently large sample sizes.

  Aug. 2017, Psychiatry and clinical neurosciences, 71(8) (8), 562 - 568, English, International magazine

  Scientific journal


• Aberrant telomere length and mitochondrial DNA copy number in suicide completers.

  Otsuka I, Izumi T, Boku S, Kimura A, Zhang Y, Mouri K, Okazaki S, Shiroiwa K, Takahashi M, Ueno Y, Shirakawa O, Sora I, Hishimoto A.

  Short telomere length (TL) occurs in individuals under psychological stress, and with various psychiatric diseases. Recent studies have also reported mitochondrial DNA copy number (mtDNAcn) alterations under several neuropsychiatric conditions. However, no study has examined whether aberrant TL or mtDNAcn occur in completed suicide, one of the most serious outcomes of mental illnesses. TL and mtDNAcn in post-mortem samples from 528 suicide completers without severe physical illness (508 peripheral bloods; 20 brains) and 560 samples from control subjects (peripheral bloods from 535 healthy individuals; 25 post-mortem brains) were analysed by quantitative polymerase chain reaction. Suicide completers had significantly shorter TL and higher mtDNAcn of peripheral bloods with sex/age-dependent differences (shorter TL was more remarkably in female/young suicides; higher mtDNAcn more so in male/elderly suicides). The normal age-related decline of TL and mtDNAcn were significantly altered in suicide completers. Furthermore, shorter TL and lower mtDNAcn of post-mortem prefrontal cortex were seen in suicide completers compared to controls. This study shows the first association of aberrant telomeres and mtDNA content with suicide completion. Our results indicate that further research on telomere shortening and mitochondrial dysfunction may help elucidate the molecular underpinnings of suicide-related pathophysiology.

  Lead, Jun. 2017, Scientific Reports, 7(1) (1), 3176 - 3176, English, International magazine

  [Refereed]

  Scientific journal


• Optimizing outcomes in clozapine rechallenge following neutropenia using human leukocyte antigen typing: A case report.

  Naruhisa Yamaki, Akitoyo Hishimoto, Ikuo Otsuka, Toru Sasada, Shuken Boku, Takeo Saito, Yuka Yasuda, Hidenaga Yamamori, Masashi Ikeda, Manabu Ikeda, Ichiro Sora, Nakao Iwata, Ryota Hashimoto

  Apr. 2017, Psychiatry and clinical neurosciences, 71(4) (4), 289 - 290, English, International magazine


• Association study of MIF promoter polymorphisms with suicide completers in the Japanese population.

  Naofumi Shimmyo, Akitoyo Hishimoto, Ikuo Otsuka, Satoshi Okazaki, Shuken Boku, Kentaro Mouri, Tadasu Horai, Motonori Takahashi, Yasuhiro Ueno, Osamu Shirakawa, Ichiro Sora

  BACKGROUND: Numerous studies suggest that inflammation plays a key role in suicidal behavior. Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine, has received increasing attention in depression research. However, no study has investigated whether MIF has genetic involvement in completed suicide. In this study, we sought to explore the relationship between two functional polymorphisms on the MIF gene promoter (MIF-794CATT5-8 microsatellite and MIF-173G/C single-nucleotide polymorphism [SNP]) and completed suicide by using one of the largest samples of suicide completers ever reported. METHODS: The subjects comprised 602 suicide completers and 728 healthy controls. We genotyped MIF-794CATT5-8 microsatellite by polymerase chain reaction-based size discrimination assay and MIF-173G/C SNP by TaqMan® SNP genotyping assay. The allele-, genotype-, or haplotype-based association analyses between the suicide completers and the controls were carried out with the χ2 test, the Cochran-Armitage trend test, or Fisher's exact test. RESULTS: Analyses of allele or genotype frequency distributions of the polymorphisms studied here did not reveal any significant differences between the suicide completers and the controls. Haplotype analysis also revealed no association with completed suicide. CONCLUSION: To our knowledge, this is the first study that has examined the genetic association between MIF and completed suicide. Our results suggest that the effects of MIF-794CATT5-8 microsatellite and MIF-173G/C SNP on the MIF gene promoter might not contribute to the genetic risk of completed suicide in the Japanese population.

  2017, Neuropsychiatric disease and treatment, 13, 899 - 908, English, International magazine

  Scientific journal


• The cell cycle-related genes as biomarkers for schizophrenia.

  Satoshi Okazaki, Shuken Boku, Ikuo Otsuka, Kentaro Mouri, Shinsuke Aoyama, Kyoichi Shiroiwa, Ichiro Sora, Aiko Fujita, Yutaka Shirai, Osamu Shirakawa, Masahiro Kokai, Akitoyo Hishimoto

  BACKGROUND: Recent studies suggest that genomic abnormalities such as single nucleotide polymorphisms (SNPs) and copy number variations (CNVs) may elevate the risk of schizophrenia. Such genomic abnormalities often occur during chromosomal DNA replication in the S phase of cell cycle. In addition, several studies showed that abnormal expressions of several cell cycle-related genes are associated with schizophrenia. Therefore, here we compared mRNA expression levels of cell cycle-related genes in peripheral blood cells between patients with schizophrenia and healthy controls. METHOD: mRNA expression levels of cell cycle-related genes in peripheral blood cells from patients with schizophrenia and healthy controls were measured with quantitative reverse transcription polymerase chain reaction (Q-RT-PCR). The discovery, replication and intervention studies with Q-RT-PCR were performed as follows: discovery (40 cases and 20 controls), replication (82 cases and 74 controls) and intervention (22 cases and 18 controls). RESULT: Nine genes were identified in the discovery and replication stages as schizophrenia-associated genes. Moreover, the combination of mRNA expression levels of CDK4, MCM7 and POLD4 was identified as a potential biomarker for schizophrenia with multivariate logistic regression analysis. The intervention stage revealed that the mRNA expression levels of these three genes were significantly decreased in the acute state of schizophrenia, and CDK4 was significantly recovered in the remission state of schizophrenia. CONCLUSION: The combination of mRNA expression levels of three cell cycle-related genes such as CDK4, MCM7 and POLD4 is expected to be a candidate for useful biomarkers for schizophrenia. Especially, the mRNA expression changes of CDK4 may be potential as both trait and state markers for schizophrenia.

  Oct. 2016, Progress in neuro-psychopharmacology & biological psychiatry, 70, 85 - 91, English, International magazine

  Scientific journal


• A decrease in protein level and a missense polymorphism of KIF17 are associated with schizophrenia.

  Woraphat Ratta-Apha, Kentaro Mouri, Shuken Boku, Hiroki Ishiguro, Satoshi Okazaki, Ikuo Otsuka, Ichiro Sora, Tadao Arinami, Osamu Shirakawa, Akitoyo Hishimoto

  It has been shown that the dysfunction of N-methyl-d-asparate (NMDA) receptors-mediated neurotransmission plays a role in the pathophysiology of schizophrenia. Especially, GluN2B, a subunit of NMDA receptors, associated trafficking complex is altered in the prefrontal cortex of schizophrenia. The kinesin superfamily motor protein 17 (KIF17) is known as a transporter of NR2B.Previous studies showed that a structural variant of KIF17 gene is associated with a schizophrenic phenotype. Therefore, here we investigated KIF17 levels in postmortem prefrontal cortex in schizophrenia and the association of a missense polymorphism (Ile341Val) in KIF17 with schizophrenia. The protein expression of KIF17 in schizophrenic postmortem brains was significantly lower than that in controls. Next, the association of missense polymorphisms (rs631375, rs13375609, rs522496 and rs2296225) of KIF17 gene in 567 schizophrenia and 710 healthy subjects was examined. Both genotypic distribution and allelic frequency of rs2296225 polymorphism were significantly different between the chronic schizophrenia subjects and controls. However, our findings described above were not replicated with the independent subjects (555 schizophrenia and 814 healthy controls). Furthermore, the two alleles of rs2296225 polymorphism did not affect the mRNA expression of KIF17. These results suggest that the dysfunction of KIF17 might be involved in the pathophysiology of schizophrenia.

  Dec. 2015, Psychiatry research, 230(2) (2), 424 - 9, English, International magazine

  Scientific journal


• Association analysis of the HLA-DRB1*01 and HLA-DRB1*04 with schizophrenia by tag SNP genotyping in the Japanese population.

  Woraphat Ratta-apha, Shuken Boku, Kentaro Mouri, Satoshi Okazaki, Ikuo Otsuka, Yuichiro Watanabe, Ayako Nunokawa, Toshiyuki Someya, Osamu Shirakawa, Ichiro Sora, Akitoyo Hishimoto

  Sep. 2015, Psychiatry research, 229(1-2) (1-2), 627 - 8, English, International magazine


• Association analysis of the Cadherin13 gene with schizophrenia in the Japanese population.

  Ikuo Otsuka, Yuichiro Watanabe, Akitoyo Hishimoto, Shuken Boku, Kentaro Mouri, Kyoichi Shiroiwa, Satoshi Okazaki, Ayako Nunokawa, Osamu Shirakawa, Toshiyuki Someya, Ichiro Sora

  BACKGROUND: Cadherin13 (CDH13) is a glycosylphosphatidylinositol-anchored cell adhesion molecule that plays a crucial role in morphogenesis and the maintenance of neuronal circuitry. CDH13 has been implicated in the susceptibility to a variety of psychiatric diseases. A recent genome-wide association study using Danish samples showed, for the first time, the involvement of a single nucleotide polymorphism (SNP) of CDH13 (intronic SNP rs8057927) in schizophrenia. Here, we investigated the association between other SNPs of CDH13 and schizophrenia and tried to replicate the association for the SNP of rs8057927, in the Japanese population. METHODS: Using TaqMan(®) SNP genotyping assays, five tag SNPs (rs12925602, rs7193788, rs736719, rs6565051, and rs7204454) in the promoter region of CDH13 were examined for their association with schizophrenia in two independent samples. The first sample comprised 665 patients and 760 controls, and the second sample comprised 677 patients and 667 controls. One tag SNP for rs8057927 was also examined for the association with schizophrenia in the first sample set. RESULTS: A GACAG haplotype of the five SNPs in the promoter region of CDH13 was significantly associated with schizophrenia in the first sample set (P=0.016 and corrected P=0.098). A combined analysis of the GACAG haplotype with the second sample set enhanced the significance (P=0.0026 and corrected P=0.021). We found no association between rs8057927 and schizophrenia in the first sample set. CONCLUSION: Our results suggest that CDH13 may contribute to the genetic risk of schizophrenia. Further replication on the association of CDH13 with schizophrenia and functional studies are required to confirm the current findings.

  2015, Neuropsychiatric disease and treatment, 11, 1381 - 93, English, International magazine

  Scientific journal


• Association analysis of putative cis-acting polymorphisms of interleukin-19 gene with schizophrenia.

  Satoshi Okazaki, Yuichiro Watanabe, Akitoyo Hishimoto, Toru Sasada, Kentaro Mouri, Kyoichi Shiroiwa, Noriomi Eguchi, Woraphat Ratta-Apha, Ikuo Otsuka, Ayako Nunokawa, Naoshi Kaneko, Masako Shibuya, Toshiyuki Someya, Osamu Shirakawa, Ichiro Sora

  BACKGROUND: Genome-wide association studies (GWAS) and gene expression analyses have revealed that single nucleotide polymorphisms (SNPs) associated with multifactorial diseases, such as schizophrenia, are significantly more likely to be associated with expression quantitative trait loci (eQTL). It was recently suggested that an immune system imbalance plays an important role in the pathogenesis of schizophrenia. Interleukin-19 is a novel cytokine that may play multiple roles in immune regulation and various diseases. METHOD: We selected eight tag SNPs in the eQTL of the IL-19 gene. Seven of the SNPs are putative cis-acting SNPs. Then, we conducted a case-control study using two independent samples. The first sample comprised 567 schizophrenia patients and 710 controls, and the second sample comprised 677 schizophrenia patients and 667 controls. RESULT: We identified the TGAA haplotype as being significantly associated with schizophrenia (p=0.0036 and corrected p=0.0264), although a combined analysis of the TGAA haplotype with the replication samples exhibited a nominally significant difference (p=0.022 and corrected p=0.235). CONCLUSIONS: These results suggest that the IL-19 gene might slightly contribute to the genetic risk of schizophrenia. Thus, further research on the association of eQTL SNPs with schizophrenia is warranted.

  Apr. 2014, Progress in neuro-psychopharmacology & biological psychiatry, 50, 151 - 6, English, International magazine

  Scientific journal

• 不安と自殺・自傷：特に遺伝学的知見の観点から.

  大塚郁夫, 谷藤貴紀

  Lead, Jun. 2022, 臨床精神医学, 51;9:p1057-1063, Japanese

  [Invited]

  Introduction scientific journal


• 臨床での活用が期待される自殺の生物学的知見.

  大塚郁夫, 菱本明豊.

  Lead, Oct. 2021, 医学のあゆみ, 279;1:p29-34, Japanese

  Introduction commerce magazine


• 自殺の神経生物学的異常.

  大塚郁夫, 菱本明豊.

  Lead, Jun. 2021, 臨床精神医学, 50;6:p577-583, Japanese

  Introduction scientific journal


• 自殺の遺伝学的研究の現況.

  大塚郁夫, 菱本明豊.

  Lead, 2020, 日本生物学的精神医学会誌 31;3:p134-140


• 自殺既遂の生物学的研究.

  大塚郁夫, 曽良一郎, 菱本明豊.

  Lead, Jun. 2016, 日本神経精神薬理学雑誌 36:p55-62

• Facilitating Resilience after PTSD: A Translational Approach.

  Otsuka I, Hishimoto A

  Contributor, Resilience and Suicide., Nova Science Publishers, 2018


• Depression Frontier 2; うつ病臨床のこんな疑問に答える −脳科学からのアプローチ−

  大塚 郁夫, 菱本 明豊

  Contributor, 自殺の遺伝子研究, 医薬ジャーナル社, 2017

• 若者を自殺に追い込む生物学的異常と可逆性：エピゲノム・シングルセルダイナミクス

  菱本 明豊, 古屋敷 智之, 大塚 郁夫, 寺尾 知可史

  日本学術振興会, 科学研究費助成事業, 基盤研究(B), 神戸大学, 01 Apr. 2024 - 31 Mar. 2027


• Epigenetic pathomechanisms of accelerated aging in schizophrenia

  岡崎 賢志, 蓬莱 政, 大塚 郁夫

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Kobe University, 01 Apr. 2024 - 31 Mar. 2027


• Elucidation for genetic suicide risk and suicide-related aberrant somatic mosaicism through GWAS

  大塚 郁夫, 菱本 明豊, 寺尾 知可史

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Kobe University, 01 Apr. 2024 - 31 Mar. 2027


• Realization of a society where child abuse, depression and suicide are “zero”

  Principal investigator

  JST, Moonshot goal 9, 2025 - 2026


• Prediction and elucidation for suicide risk using polygenic risk score analysis

  Hishimoto Akitoyo

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 01 Apr. 2021 - 31 Mar. 2024

  In this study, we conducted additional sampling and genotyping of suicidal samples and constructed the largest suicidal GWAS data in East Asian population. We identified the SNPs located on SP4 gene promoter region associated with suicide risk in East Asian populations. Furthermore, somatic cell mosaicism analysis using suicide GWAS data led to the novel finding of abnormal increase in autosomal and X-chromosome mosaicism in suicide decedents. Furthermore, we provided the largest East Asian GWAS data for suicide death to the International Suicide Genome Consortium, conducted the largest ever multi-ethnic GWAS of suicidal behavior, and identified multiple candidate gene regions. We found that the more we scaled up the Japanese suicide GWAS used as base data, the more accurate the prediction of suicide PRS became.


• Study of biomarker for youth suicide risk through blood telomere length

  Mouri Kentaro

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Kobe University, 01 Apr. 2021 - 31 Mar. 2024

  In the midst of the serious social situation where the high suicide rate among young people continues, the applicants discovered the phenomenon that "biological age indicators such as peripheral blood telomere length and epigenetic age are aberrantly aging in young Japanese suicide victims." in this study, the applicants confirmed this finding of abnormal biological aging in young suicide victims by scaling up the sample size. Then we measured peripheral blood telomere length and epigenetic age of young people at risk of suicide, and investigated whether they could be used as biomarkers of suicide risk in young people by examining the association with the presence or absence of suicidal behavior and the progress of psychological scores. In particular, epigenetic age was statistically older in the peripheral blood of highly suicidal young people with higher impulsivity.


• A worldwide study of genetic factor for suicide

  Hishimoto Akitoyo

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Fund for the Promotion of Joint International Research (Fostering Joint International Research (B)), 27 Oct. 2020 - 31 Mar. 2024

  In this application, we expanded the International Suicide Genetics Consortium (hereinafter referred to as ISGC), which was the first in the world to be launched, in collaboration with Columbia University's Department of Psychiatry, the world's leading institution for suicide research. The applicants provided ISGC with Asia's largest GWAS data on suicides, conducted the largest cross-ethnic GWAS on suicidal behavior ever with 43,871 cases, and identified several candidate gene regions. We also demonstrated polygenic associations between suicidal behavior and various psychiatric-related human phenotypes. Comparative analysis of polygenic risk scores for major depressive disorder/schizophrenia in suicide GWAS between multi-ethniticites revealed that the polygenic effects of MDD/SCZ on suicide were more significant for Europeans than for East Asians.


• 網羅的ゲノム・エピゲノムデータを用いた若年自殺行動の機序解明とリスクマーカー開発

  先進医薬研究振興財団, 若手研究者助成（新規 及び 継続）, 2023 - 2024, Principal investigator


• Realization of a society where child abuse and suicide are “zero”

  Principal investigator

  JST, Moonshot goal 9, 2023 - 2024


• Development of clinical implementation of pharmacogenomics in drug induced parkinsonism

  AMED, ゲノム創薬基盤推進研究事業, 2022 - 2024, Coinvestigator


• Development for predicting suicide risk in psychiatric patients with polygenic risk scores of Japanese suicide

  AMED, 障害者対策総合研究開発事業, 2022 - 2024, Coinvestigator


• Study of biomarker for youth suicide risk through genome and epigenome-wide data

  Otsuka Ikuo

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Early-Career Scientists, Kobe University, 01 Apr. 2021 - 31 Mar. 2023

  Suicides (especially among young people) are increasing both in Japan and around the world. In this study, regarding youth suicide risk for which biomarkers and biological mechanisms have not yet been clarified, the novel preliminary findings "aberrant telomere shortening, abnormal acceleration of epigenetic age, and GTF2iRD1 SNP association in young suicides" that the applicant already identified were successfully replicated in an independent young suicide cohort. In addition, the applicant identified an aberrant increase in natural killer cells in juvenile suicides, and genetically mapped the correlation between suicidal behavior and other psychiatric traits classified into non-fatal suicide attempt and suicide death.


• Development of suicide risk markers for young people focusing on telomere length

  Mouri Kentaro

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Kobe University, 01 Apr. 2018 - 31 Mar. 2021

  For the students with suicide high-risk and non-suicidal healthy students, gDNA from peripheral blood, MWAS-based telomere length by using Infinium Human Methylation 450K BeadChip, suicide-attempt history, and various suicide-related clinical scales such as HAMD17, SRS18 and C-SSRS were obtained. We found shorter MWAS-based telomeres in young suicidal subjects compared to the healthy group. We also identified the association between suicide risk in women after middle age and rs12415800 related to SIRT1 gene which is well-known to be related to telomere dynamics.


• Analysis of aberrant methylation on CpG island of X chromosome in male schizophrenia

  Otsuka Ikuo

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (B), Kobe University, 01 Apr. 2016 - 31 Mar. 2019

  Each CpG methylation status of CpG island A in 40 male schizophrenia (SCZ) patients and 40 healthy males (as "replication cohort") were analysed by MassARRAY; I revealed that approximately 30% of male SCZ have aberrant higher methylation of CpG island A. In addition, I investigated the association between TAF1 gene expression and methylation status of CpG island A using data from replication cohort. As in vitro study, I have been trying CRISPR-Cas experiments using male-derived neural stem cells and iPSC-derived neural cells in order to further clarify the biological importance of aberrant methylation of CpG island A.


• Telomere length and mitochondrial DNA copy number in blood and brain of suicide completers

  Shiroiwa Kyoichi, Otsuka Ikuo

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (B), Kobe University, 01 Apr. 2016 - 31 Mar. 2019

  Short telomere length (TL) and alterations of mitochondrial DNA copy number (mtDNAcn) occur in individuals under psychological stress, and with various psychiatric diseases. However, no study has examined whether aberrant TL or mtDNAcn occur in completed suicide. TL and mtDNAcn in samples from suicide completers (508 peripheral bloods; 20 brains) and controls (peripheral bloods from 535 healthy individuals; 25 post-mortem brains) were analysed by qPCR. Suicide completers had significantly shorter TL and higher mtDNAcn of bloods with age-dependent differences (shorter TL was more remarkably in young suicides; higher mtDNAcn more so in elderly suicides). The normal age-related decline of TL and mtDNAcn were significantly altered in suicide completers. Furthermore, shorter TL and lower mtDNAcn of post-mortem prefrontal cortex were seen in suicide completers compared to controls. This study shows the first association of aberrant telomeres and mtDNA content with suicide completion.


• 大規模な自殺完遂者・未遂者試料を用いた自殺の遺伝因子の解明

  先進医薬研究振興財団, 海外留学助成, 2019, Principal investigator