Publications by authors named "Jun Hirata"

Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease caused by a genetic mutation in the Dmd gene. Dystrophin mutant mice (mdx) have traditionally been used for DMD research as a disease model in the preclinical stage; however, mdx mice exhibit only very mild phenotypes to partially mimic muscle degeneration and regeneration. To overcome this limitation in preclinical studies, DMD mutant rats (DMD rats) generated by CRISPR/Cas were used as a DMD model to exhibit age-dependent progressive muscle degeneration and pathophysiological features similar to DMD patients and more severe than those displayed by mdx mice.

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Here we report the largest Asian genome-wide association study (GWAS) for systemic sclerosis performed to date, based on data from Japanese subjects and comprising of 1428 cases and 112,599 controls. The lead SNP is in the FCGR/FCRL region, which shows a penetrating association in the Asian population, while a complete linkage disequilibrium SNP, rs10917688, is found in a cis-regulatory element for IRF8. IRF8 is also a significant locus in European GWAS for systemic sclerosis, but rs10917688 only shows an association in the presence of the risk allele of IRF8 in the Japanese population.

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Article Synopsis
  • The study focuses on the killer cell immunoglobulin-like receptor (KIR) that interacts with HLA class I molecules and affects natural killer cell function, highlighting its significance in immunity.
  • Researchers conducted deep sequencing of KIR genes from a large sample of individuals to enhance understanding of KIR genetics, discovering 118 alleles and establishing a detailed genetic linkage map.
  • Utilizing a highly accurate reference panel for KIR genotyping, the study also explored genetic associations with various traits, finding minimal significant links, even with those related to immune functions.
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The genetic background of intracranial artery stenosis (ICAS), a major cause of ischemic stroke, remains elusive. We performed the world's first genome-wide association study (GWAS) of ICAS using DNA samples from Japanese subjects, to identify the genetic factors associated with ICAS and their correlation with clinical features. We also conducted a phenome-wide association study (PheWAS) of the top variant identified via GWAS to determine its association with systemic disease.

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  • This study investigates the genetic factors influencing non-coding RNA (ncRNA) expression, specifically focusing on microRNAs (miRNAs) in a Japanese population, to enhance understanding of disease-associated genetic variations.
  • Researchers identified 1,275 variants linked to 40 miRNAs using advanced sequencing techniques, with many miRNAs previously not reported in European studies, highlighting the importance of diverse ancestral research.
  • Additionally, the study created a catalog of miRNA-editing sites and linked miRNA-eQTLs to complex traits, identifying miR-1908-5p as a potential key player in diseases like colorectal cancer and type 2 diabetes, thus enriching the understanding of ncRNA's role in health across different populations.
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Background: Despite evidence for the role of human leukocyte antigen (HLA) in the genetic predisposition to Parkinson's disease (PD), the complex haplotype structure and highly polymorphic feature of the major histocompatibility complex (MHC) region has hampered a unified insight on the genetic risk of PD. In addition, a majority of the reports focused on Europeans, lacking evidence on other populations.

Objectives: The aim of this study is to elucidate the genetic features of the MHC region associated with PD risk in trans-ethnic cohorts.

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  • Psoriasis is a skin disease that is caused by both genetics and the environment, but there isn’t a clear way to diagnose it yet.
  • Researchers studied blood samples from patients with two types of psoriasis and healthy people to find specific markers in the blood.
  • They discovered that some substances in the blood are different in psoriasis patients compared to healthy individuals, which could help in understanding and diagnosing the disease better.
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  • * Validation against Japanese and European HLA reference panels shows DEEP*HLA outperforms existing methods, demonstrating its ability to handle complex genetic information without being overly reliant on allele frequency relationships.
  • * The method was applied to large genetic databases, revealing distinct HLA variants associated with type 1 diabetes, highlighting its effectiveness in trans-ethnic studies and disease association analyses.
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Pulmonary alveolar proteinosis (PAP) is a devastating lung disease caused by abnormal surfactant homeostasis, with a prevalence of 6-7 cases per million population worldwide. While mutations causing hereditary PAP have been reported, the genetic basis contributing to autoimmune PAP (aPAP) has not been thoroughly investigated. Here, we conducted a genome-wide association study of aPAP in 198 patients and 395 control participants of Japanese ancestry.

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The retinoic acid receptor-related orphan nuclear receptor gamma t (RORγt), which is a promising therapeutic target for immune diseases, is a major transcription factor of genes related to psoriasis pathogenesis, such as interleukin (IL)-17A, IL-22, and IL-23R. Inspired by the co-crystal structure of RORγt, a 6-oxo-4-phenyl-hexanoic acid derivative 6a was designed, synthesized, and identified as a ligand of RORγt. The structure-activity relationship (SAR) studies in 6a, which focus on the improvement of its membrane permeability profile by introducing chlorine atoms, led to finding 12a, which has a potent RORγt inhibitory activity and a favorable pharmacokinetic profile.

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Importance: Understanding the genetic contribution of the major histocompatibility complex (MHC) region to the risk of cervical cancer (CC) will help understand how immune responses to infection with human papillomaviruses are associated with CC.

Objective: To determine whether the HLA-B*52:01 allele is associated with CC in Japanese women.

Design, Setting, And Participants: This was a multicenter genetic association study.

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  • Novel biomarkers beyond existing antibodies are needed for better rheumatoid arthritis (RA) diagnosis, and metabolome analysis shows promise in identifying these.
  • A comprehensive study analyzed plasma samples from 286 individuals, revealing seven metabolites, including elevated levels of UTP and ATP, that were significantly higher in RA patients compared to controls, while one metabolite, xanthine, was lower.
  • The findings suggest that plasma nucleotide levels, particularly in untreated RA patients, could serve as specific clinical biomarkers for RA, distinguishing it from conditions like systemic lupus erythematosus (SLE) and psoriatic arthritis (PsA).
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The retinoic acid receptor-related orphan nuclear receptor γt (RORγt), a promising therapeutic target, is a major transcription factor of genes related to psoriasis pathogenesis such as interleukin (IL)-17A, IL-22, and IL-23R. On the basis of the X-ray cocrystal structure of RORγt with , an analogue of the known piperazine RORγt inverse agonist , triazolopyridine derivatives of were designed and synthesized, and analogue was found to be a potent RORγt inverse agonist. Structure-activity relationship studies on , focusing on the treatment of its metabolically unstable cyclopentyl ring and the central piperazine core, led to a novel analogue, namely, 6-methyl--(7-methyl-8-(((2,4)-2-methyl-1-(4,4,4-trifluoro-3-(trifluoromethyl)butanoyl)piperidin-4-yl)oxy)[1,2,4]triazolo[1,5-]pyridin-6-yl)nicotinamide (), which exhibited strong RORγt inhibitory activity and a favorable pharmacokinetic profile.

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Article Synopsis
  • * Various dimensionality reduction methods (like PCA and UMAP) were used to identify distinct subpopulations and their demographic history, highlighting differences among nearby groups.
  • * The researchers found inconsistencies between polygenic risk scores and actual phenotypes, indicating that not accounting for population structure could hinder the effective use of these scores in clinical settings.
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Background: The spectrum of classical and non-classical HLA genes related to the risk of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) in the Japanese population has not been studied in detail. We conducted a case-control analysis of classical and non-classical HLA genes.

Methods: We used next-generation sequencing (NGS)-based HLA genotyping methods for mapping risk for 45 MS patients, 31 NMOSD patients, and 429 healthy controls.

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Better prescription assistance can be provided by applying basic pharmaceutical science concepts, and by considering evidence from clinical trials. For example, several drugs are currently used to treat ulcerative colitis (UC), a form of inflammatory bowel disease. In general, after a drug is administered, it is first absorbed into the upper part of the small intestine and then enters the bloodstream.

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Dental caries and periodontitis account for a vast burden of morbidity and healthcare spending, yet their genetic basis remains largely uncharacterized. Here, we identify self-reported dental disease proxies which have similar underlying genetic contributions to clinical disease measures and then combine these in a genome-wide association study meta-analysis, identifying 47 novel and conditionally-independent risk loci for dental caries. We show that the heritability of dental caries is enriched for conserved genomic regions and partially overlapping with a range of complex traits including smoking, education, personality traits and metabolic measures.

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To perform detailed fine-mapping of the major-histocompatibility-complex region, we conducted next-generation sequencing (NGS)-based typing of the 33 human leukocyte antigen (HLA) genes in 1,120 individuals of Japanese ancestry, providing a high-resolution allele catalog and linkage-disequilibrium structure of both classical and nonclassical HLA genes. Together with population-specific deep-whole-genome-sequencing data (n = 1,276), we conducted NGS-based HLA, single-nucleotide-variant and indel imputation of large-scale genome-wide-association-study data from 166,190 Japanese individuals. A phenome-wide association study assessing 106 clinical phenotypes identified abundant, significant genotype-phenotype associations across 52 phenotypes.

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Objectives: Systemic lupus erythematosus (SLE) is an autoimmune disease that is characterised by autoantibody production and widespread inflammation damaging many organs. Previous genome-wide association studies (GWASs) have revealed over 80 genetic determinants of SLE, but they collectively explain a fraction of the heritability, and only a few were proven in vivo for the involvement in SLE. We conducted a meta-analysis of SLE GWAS in the Japanese population, followed by functional analyses of a susceptibility gene with use of mutant mice.

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MicroRNAs (miRNAs) modulate the post-transcriptional regulation of target genes and are related to biology of complex human traits, but genetic landscape of miRNAs remains largely unknown. Given the strikingly tissue-specific miRNA expression profiles, we here expand a previous method to quantitatively evaluate enrichment of genome-wide association study (GWAS) signals on miRNA-target gene networks (MIGWAS) to further estimate tissue-specific enrichment. Our approach integrates tissue-specific expression profiles of miRNAs (∼1800 miRNAs in 179 cells) with GWAS to test whether polygenic signals enrich in miRNA-target gene networks and whether they fall within specific tissues.

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In this study, we examined the fasted and postprandial triacylglycerol (TG) levels in KK- A mice fed a high-fat diet (HFD) or a HFD containing either 500 ppm (0.05%) of diosgenin or 500 ppm (0.05%) of diosgenin-containing Chinese yam sanyaku.

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Psoriasis vulgaris (PsV) is an autoimmune disease of skin and joints with heterogeneity in epidemiologic and genetic landscapes of global populations. We conducted an initial genome-wide association study and a replication study of PsV in the Japanese population (606 PsV cases and 2,052 controls). We identified significant associations of the single nucleotide polymorphisms with PsV risk at TNFAIP3-interacting protein 1and the major histocompatibility complex region (P = 3.

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Recent developments in human genome genotyping and sequencing technologies, such as genome-wide association studies and whole-genome sequencing analyses, have successfully identified several risk genes of rheumatic diseases. Fine-mapping studies using the HLA imputation method revealed that classical and non-classical HLA genes contribute to the risk of rheumatic diseases. Integration of human disease genomics with biological, medical, and clinical databases should contribute to the elucidation of disease pathogenicity and novel drug discovery.

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Despite the progress in human leukocyte antigen (HLA) causal variant mapping, independent localization of major histocompatibility complex (MHC) risk from classical HLA genes is challenging. Here, we conducted a large-scale MHC fine-mapping analysis of rheumatoid arthritis (RA) in a Japanese population (6,244 RA cases and 23,731 controls) population by using HLA imputation, followed by a multi-ethnic validation study including east Asian and European populations (n = 7,097 and 23,149, respectively). Our study identified an independent risk of a synonymous mutation at HLA-DOA, a non-classical HLA gene, on anti-citrullinated protein autoantibody (ACPA)-positive RA risk (p = 1.

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