Anti-ganglionic nicotinic acetylcholine receptor (gAChR) antibodies are observed in autoimmune diseases, as well as in patients with autoimmune autonomic ganglionopathy. However, the genetic background of anti-gAChR antibodies is unclear. Here, we investigated HLA alleles in autoimmune hepatitis (AIH) patients with or without anti-gAChR antibodies.

For the identification of susceptibility loci for primary biliary cirrhosis (PBC), a genome-wide association study (GWAS) was performed in 963 Japanese individuals (487 PBC cases and 476 healthy controls) and in a subsequent replication study that included 1,402 other Japanese individuals (787 cases and 615 controls). In addition to the most significant susceptibility region, human leukocyte antigen (HLA), we identified two significant susceptibility loci, TNFSF15 (rs4979462) and POU2AF1 (rs4938534) (combined odds ratio [OR] = 1.56, p = 2.84 × 10(-14) for rs4979462, and combined OR = 1.39, p = 2.38 × 10(-8) for rs4938534). Among 21 non-HLA susceptibility loci for PBC identified in GWASs of individuals of European descent, three loci (IL7R, IKZF3, and CD80) showed significant associations (combined p = 3.66 × 10(-8), 3.66 × 10(-9), and 3.04 × 10(-9), respectively) and STAT4 and NFKB1 loci showed suggestive association with PBC (combined p = 1.11 × 10(-6) and 1.42 × 10(-7), respectively) in the Japanese population. These observations indicated the existence of ethnic differences in genetic susceptibility loci to PBC and the importance of TNF signaling and B cell differentiation for the development of PBC in individuals of European descent and Japanese individuals.

Osteoclast formation is regulated by balancing between the receptor activator of nuclear factor-κB ligand (RANKL) expressed in osteoblasts and extracellular negative regulatory cytokines such as interferon-γ (IFN-γ) and interferon-β (IFN-β), which can suppress excessive bone destruction. However, relatively little is known about intrinsic negative regulatory factors in RANKL-mediated osteoclast differentiation. Here, we show the paired-box homeodomain transcription factor Pax6 acts as a negative regulator of RANKL-mediated osteoclast differentiation. Electrophoretic mobility shift and reporter assays found that Pax6 binds endogenously to the proximal region of the tartrate acid phosphatase (TRAP) gene promoter and suppresses nuclear factor of activated T cells c1 (NFATc1)-induced TRAP gene expression. Introduction of Pax6 retrovirally into bone marrow macrophages attenuates RANKL-induced osteoclast formation. Moreover, we found that the Groucho family member co-repressor Grg6 contributes to Pax6-mediated suppression of the TRAP gene expression induced by NFATc1. These results suggest that Pax6 interferes with RANKL-mediated osteoclast differentiation together with Grg6. Our results demonstrate that the Pax6 pathway constitutes a new aspect of the negative regulatory circuit of RANKL-RANK signaling in osteoclastogenesis and that the augmentation of Pax6 might therefore represent a novel target to block pathological bone resorption.

The role of low-frequency variants in type 1 diabetes (T1D) susceptibility still remains to be clarified. In the present study, we analyzed low-frequency variants of the T1D candidate genes in Japanese. We first screened for protein-changing variants of 24 T1D candidate genes in 96 T1D patients and 96 control subjects, and then the association with T1D was tested in 706 T1D patients and 863 control subjects recruited from the collaborating institutions in Japan. In total, 56 protein-changing variants were discovered; among them, 34 were low-frequency variants (allele frequency < 5%). The association analysis of the low-frequency variants revealed that only the A908V variant of GLIS3 was strongly associated with resistance to T1D (Haldane's odds ratio = 0.046, p = 8.21 × 10(-4), and pc=2.22 × 10(-2)). GLIS3 is a zinc finger transcription factor that is highly expressed in pancreatic beta cells, and regulates beta cell development and insulin gene expression. GLIS3 mRNA is also moderately expressed in the human thymus. The precise mechanism responsible for the association is unclear at present, but the A908V variant may affect autoimmunity to the GLIS3 protein itself; the 908V containing epitope may induce central or peripheral tolerance more efficiently than that of 908A.

Since vascular endothelial growth factor (VEGF) has a strong effect on induction of vascular permeability, VEGF is an attractive candidate gene for development of diabetic macular edema (ME). Among the 378 patients with type 2 diabetes studied, 203 patients had no retinopathy, 93 had non-proliferative diabetic retinopathy (NPDR), and 82 had proliferative diabetic retinopathy (PDR). ME was present in 16 patients with NPDR and 47 patients with PDR. We genotyped three VEGF polymorphisms: C-2,578A, G-1,154A, and C-634G. Genotype and allele distribution of C-634G, but not C-2,578A or G-1,154A, were significantly different between patients with and without diabetic retinopathy. Logistic regression analysis revealed that the C-634G genotype was a risk factor for DR (p = 0.002), and furthermore for ME (p = 0.047), independently from severity of DR, with the -634C allele increasing the risk. Macular thickness measured by optical coherence tomography was correlated with the C-634G genotype, with the trend increasing with the presence of more -634C alleles (p = 0.006). Stepwise regression analysis showed that duration of diabetes and presence of the C-634G genotype were independent predictors of macular thickness. In addition, basic transcriptional activity levels associated with the -634C allele were greater compared to those seen with the -634G allele in human glioma and lymphoblastic T-lymphocyte cells. These results demonstrate that the VEGF C-634G polymorphism is a genetic risk factor for ME as well as DR.

It has been previously demonstrated that a single nucleotide polymorphism (SNP) in the IL13 promoter region, IL13 -1055T>C (rs1800925), was associated with susceptibility to severe malaria in Thais. In the present study, fine association mapping for a cytokine gene cluster including IL4, IL5, and IL13 on chromosome 5q31 was conducted using the same malaria subjects to refine the region containing a primary variant or a haplotype susceptible to severe malaria.

Autoimmune hepatitis (AIH) is an autoimmune liver disease and cirrhosis is sometimes complicated with AIH at diagnosis, influencing its prognosis. TNFAIP3 gene encodes A20, an inhibitor of nuclear factor-κB pathway, and is a susceptibility gene for autoimmune diseases. We investigated deleterious variants in the coding regions of TNFAIP3 gene of Japanese AIH patients or those with cirrhosis. The deleterious variants in the coding regions of TNFAIP3 gene were analyzed by the cycle sequencing method and the frequencies of deleterious TNFAIP3 alleles of AIH or AIH with cirrhosis were compared with those of Japanese controls. The deleterious alleles in TNFAIP3 were not associated with AIH. A significant association was shown for the deleterious alleles in TNFAIP3 (P = 0.0180, odds ratio (OR) 4.28, 95% confidence interval (CI) 1.53-11.95) with AIH with cirrhosis at presentation. The serum IgM levels in AIH patients with deleterious alleles in TNFAIP3 were tended to be lower than those without (P = 0.0152, Q = 0.1216). The frequency of deleterious alleles in TNFAIP3 was higher in the AIH subset without the DRB1 risk alleles than that with (P = 0.0052, OR 5.10, 95%CI 1.55-16.74). The deleterious alleles in TNFAIP3were associated with AIH with cirrhosis.

An outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occurred aboard the Diamond Princess cruise ship between her January 20 departure and late February 2020. Here, we used phylodynamic analyses to investigate the transmission dynamics of SARS-CoV-2 during the outbreak. Using a Bayesian coalescent-based method, the estimated mean nucleotide substitution rate of 240 SARS-CoV-2 whole-genome sequences was approximately 7.13 × 10-4 substitutions per site per year. Population dynamics and the effective reproductive number (Re) of SARS-CoV-2 infections were estimated using a Bayesian framework. The estimated origin of the outbreak was January 21, 2020. The infection spread substantially before quarantine on February 5. The Re peaked at 6.06 on February 4 and gradually declined to 1.51, suggesting that transmission continued slowly even after quarantine. These findings highlight the high transmissibility of SARS-CoV-2 and the need for effective measures to control outbreaks in confined settings.

Hepatitis B (HB) vaccines (Heptavax-II and Bimmugen) designed based on HBV genotypes A and C are mainly used for vaccination against HB in Japan. To determine whether there are differences in the genetic background associated with vaccine responsiveness, genome-wide association studies were performed on 555 Heptavax-II and 1193 Bimmugen recipients. Further HLA imputation and detailed analysis of the association with HLA genes showed that two haplotypes, DRB1*13:02-DQB1*06:04 and DRB1*04:05-DQB1*04:01, were significantly associated in comparison with high-responders (HBsAb > 100 mIU/mL) for the two HB vaccines. In particular, HLA-DRB1*13:02-DQB1*06:04 haplotype is of great interest in the sense that it could only be detected by direct analysis of the high-responders in vaccination with Heptavax-II or Bimmugen. Compared with healthy controls, DRB1*13:02-DQB1*06:04 was significantly less frequent in high-responders when vaccinated with Heptavax-II, indicating that high antibody titers were less likely to be obtained with Heptavax-II. As Bimmugen and Heptavax-II tended to have high and low vaccine responses to DRB1*13:02, 15 residues were found in the Heptavax-II-derived antigenic peptide predicted to have the most unstable HLA-peptide binding. Further functional analysis of selected hepatitis B patients with HLA haplotypes identified in this study is expected to lead to an understanding of the mechanisms underlying liver disease.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing coronavirus disease 2019 (COVID-19) was announced as an outbreak by the World Health Organization (WHO) in January 2020 and as a pandemic in March 2020. The majority of infected individuals have experienced no or only mild symptoms, ranging from fully asymptomatic cases to mild pneumonic disease. However, a minority of infected individuals develop severe respiratory symptoms. The objective of this study was to identify susceptible HLA alleles and clinical markers that can be used in risk prediction model for the early identification of severe COVID-19 among hospitalized COVID-19 patients. A total of 137 patients with mild COVID-19 (mCOVID-19) and 53 patients with severe COVID-19 (sCOVID-19) were recruited from the Center Hospital of the National Center for Global Health and Medicine (NCGM), Tokyo, Japan for the period of February-August 2020. High-resolution sequencing-based typing for eight HLA genes was performed using next-generation sequencing. In the HLA association studies, HLA-A*11:01:01:01 [Pc = 0.013, OR = 2.26 (1.27-3.91)] and HLA-C*12:02:02:01-HLA-B*52:01:01:02 [Pc = 0.020, OR = 2.25 (1.24-3.92)] were found to be significantly associated with the severity of COVID-19. After multivariate analysis controlling for other confounding factors and comorbidities, HLA-A*11:01:01:01 [P = 3.34E-03, OR = 3.41 (1.50-7.73)], age at diagnosis [P = 1.29E-02, OR = 1.04 (1.01-1.07)] and sex at birth [P = 8.88E-03, OR = 2.92 (1.31-6.54)] remained significant. The area under the curve of the risk prediction model utilizing HLA-A*11:01:01:01, age at diagnosis, and sex at birth was 0.772, with sensitivity of 0.715 and specificity of 0.717. To the best of our knowledge, this is the first article that describes associations of HLA alleles with COVID-19 at the 4-field (highest) resolution level. Early identification of potential sCOVID-19 could help clinicians prioritize medical utility and significantly decrease mortality from COVID-19.

The aims of this subanalysis of the COLM trial [NCT00454662] were to compare visit-to-visit variability (VVV) of blood pressure (BP) between age groups and between two treatment combinations, that is, the angiotensin II receptor blocker, olmesartan combined with a calcium channel blocker (CCB), or a diuretic and to investigate the effect of VVV of BP on cardiovascular events in elderly hypertensive patients.

Ezetimibe inhibits Niemann-Pick C1-like 1 (NPC1L1), an apical membrane cholesterol transporter of enterocytes, thereby reduces intestinal cholesterol absorption. This treatment also increases extrahepatic reverse cholesterol transport via an undefined mechanism. To explore this, we employed a trans-intestinal cholesterol efflux (TICE) assay, which directly detects circulation-to-intestinal lumen 3H-cholesterol transit in a cannulated jejunal segment, and found an increase of TICE by 45%. To examine whether such increase in efflux occurs at the intestinal brush border membrane(BBM)-level, we performed luminal perfusion assays, similar to TICE but the jejunal wall was labelled with orally-given 3H-cholesterol, and determined elevated BBM-to-lumen cholesterol efflux by 3.5-fold with ezetimibe. Such increased efflux probably promotes circulation-to-lumen cholesterol transit eventually; thus increases TICE. Next, we wondered how inhibition of NPC1L1, an influx transporter, resulted in increased efflux. When we traced orally-given 3H-cholesterol in mice, we found that lumen-to-BBM 3H-cholesterol transit was rapid and less sensitive to ezetimibe treatment. Comparison of the efflux and fractional cholesterol absorption revealed an inverse correlation, indicating the efflux as an opposite-regulatory factor for cholesterol absorption efficiency and counteracting to the naturally-occurring rapid cholesterol influx to the BBM. These suggest that the ezetimibe-stimulated increased efflux is crucial in reducing cholesterol absorption. Ezetimibe-induced increase in cholesterol efflux was approximately 2.5-fold greater in mice having endogenous ATP-binding cassette G5/G8 heterodimer, the major sterol efflux transporter of enterocytes, than the knockout counterparts, suggesting that the heterodimer confers additional rapid BBM-to-lumen cholesterol efflux in response to NPC1L1 inhibition. The observed framework for intestinal cholesterol fluxes may provide ways to modulate the flux to dispose of endogenous cholesterol efficiently for therapeutic purposes.

Previous genome-wide association studies have evaluated the impact of common genetic variants and identified several non-HLA risk loci associated with autoimmune liver diseases. More recent genome-wide association studies and replication analyses reported an association between variants of the CARD10 polymorphism rs6000782 and risk of type 1 autoimmune hepatitis (AIH). In this case-control study, we genotyped 326 Japanese AIH patients and 214 control subjects.

A recent genome-wide association study (GWAS) using chronic HBV (hepatitis B virus) carriers with and without hepatocellular carcinoma (HCC) in five independent Chinese populations found that one SNP (rs17401966) in KIF1B was associated with susceptibility to HCC. In the present study, a total of 580 HBV-derived HCC cases and 1351 individuals with chronic hepatitis B (CHB) or asymptomatic carrier (ASC) were used for replication studies in order to evaluate the reported association with HBV-derived HCC in other East Asian populations.

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that regulate expression of a number of genes associated with the cellular differentiation and development. Here, we show the abundant and ubiquitous expression of a newly identified splicing variant of mouse Pparγ (Pparγ1sv) that encodes PPARγ1 protein, and its importance in adipogenesis. The novel splicing variant has a unique 5'-UTR sequence, relative to those of Pparγ1 and Pparγ2 mRNAs, indicating the presence of a novel transcriptional initiation site and promoter for Pparγ expression. Pparγ1sv was highly expressed in the white and brown adipose tissues at levels comparable to Pparγ2. Pparγ1sv was synergistically up-regulated with Pparγ2 during adipocyte differentiation of 3T3-L1 cells and mouse primary cultured preadipocytes. Inhibition of Pparγ1sv by specific siRNAs completely abolished the induced adipogenesis in 3T3-L1 cells. C/EBPβ and C/EBPδ activated both the Pparγ1sv and Pparγ2 promoters in 3T3-L1 preadipocytes. These findings suggest that Pparγ1sv and Pparγ2 synergistically regulate the early stage of the adipocyte differentiation.

Recent genome-wide association studies suggest that genetic factors contribute to primary biliary cirrhosis (PBC) susceptibility. Although several reports have demonstrated that the interleukin (IL) 12 signaling pathway is involved in PBC pathogenesis, its precise genetic factors have not been fully clarified. Here, we performed an association analysis between IL12A, IL12RB, and signal transducer and activator of transcription 4 (STAT4) genetic variations and susceptibility to PBC. Single nucleotide polymorphisms (SNPs) were genotyped in 395 PBC patients and 458 healthy subjects of Japanese ethnicity and evaluated for associations with PBC susceptibility, anti-nuclear antibody (ANA) status, and anti-mitochondrial antibody (AMA) status. We detected significant associations with PBC susceptibility for several STAT4 SNPs (rs10168266; P = 9.4 × 10(-3), rs11889341; P = 1.2 × 10(-3), rs7574865; P = 4.0 × 10(-4), rs8179673; P = 2.0 × 10(-4), and rs10181656; P = 4.2 × 10(-5)). Three risk alleles (rs7574865; P = 0.040, rs8179673; P = 0.032, and rs10181656; P = 0.031) were associated with ANA status, but not with AMA positivity. Our findings confirm that STAT4 is involved in PBC susceptibility and may play a role in ANA status in the Japanese population.

Previous studies have revealed the association between SNPs located on human leukocyte antigen (HLA) class II genes, including HLA-DP and HLA-DQ, and chronic hepatitis B virus (HBV) infection, mainly in Asian populations. HLA-DP alleles or haplotypes associated with chronic HBV infection or disease progression have not been fully identified in Asian populations. We performed trans-ethnic association analyses of HLA-DPA1, HLA-DPB1 alleles and haplotypes with hepatitis B virus infection and disease progression among Asian populations comprising Japanese, Korean, Hong Kong, and Thai subjects. To assess the association between HLA-DP and chronic HBV infection and disease progression, we conducted high-resolution (4-digit) HLA-DPA1 and HLA-DPB1 genotyping in a total of 3,167 samples, including HBV patients, HBV-resolved individuals and healthy controls. Trans-ethnic association analyses among Asian populations identified a new risk allele HLA-DPB1*09 ∶ 01 (P = 1.36 × 10(-6); OR= 1.97; 95% CI, 1.50-2.59) and a new protective allele DPB1*02 ∶ 01 (P = 5.22 × 10(-6); OR = 0.68; 95% CI, 0.58-0.81) to chronic HBV infection, in addition to the previously reported alleles. Moreover, DPB1*02 ∶ 01 was also associated with a decreased risk of disease progression in chronic HBV patients among Asian populations (P = 1.55 × 10(-7); OR = 0.50; 95% CI, 0.39-0.65). Trans-ethnic association analyses identified Asian-specific associations of HLA-DP alleles and haplotypes with HBV infection or disease progression. The present findings will serve as a base for future functional studies of HLA-DP molecules in order to understand the pathogenesis of HBV infection and the development of hepatocellular carcinoma.

Elucidation of the genetic susceptibility factors for diabetic retinopathy (DR) is important to gain insight into the pathogenesis of DR, and may help to define genetic risk factors for this condition. In the present study, we conducted a three-stage genome-wide association study (GWAS) to identify DR susceptibility loci in Japanese patients, which comprised a total of 837 type 2 diabetes patients with DR (cases) and 1,149 without DR (controls). From the stage 1 genome-wide scan of 446 subjects (205 cases and 241 controls) on 614,216 SNPs, 249 SNPs were selected for the stage 2 replication in 623 subjects (335 cases and 288 controls). Eight SNPs were further followed up in a stage 3 study of 297 cases and 620 controls. The top signal from the present association analysis was rs9362054 in an intron of RP1-90L14.1 showing borderline genome-wide significance (Pmet = 1.4×10(-7), meta-analysis of stage 1 and stage 2, allele model). RP1-90L14.1 is a long intergenic non-coding RNA (lincRNA) adjacent to KIAA1009/QN1/CEP162 gene; CEP162 plays a critical role in ciliary transition zone formation before ciliogenesis. The present study raises the possibility that the dysregulation of ciliary-associated genes plays a role in susceptibility to DR.

A number of disease-associated genetic markers for common liver diseases have been identified using genome-wide association studies (GWASs). The GWAS strategy is based on genome-wide single-nucleotide polymorphism typing technologies, which are now commercially available, accompanied by statistical methods to identify host genetic factors that are associated with target diseases or complex genetic traits. One of the most striking features of the GWAS strategy is the ability to identify unexpected disease-associated genetic markers across the entire human genome. Here, we describe the technological aspects of the GWAS strategy with examples from actual GWAS reports related to hepatitis research, including drug response for patients with chronic hepatitis C, susceptibility to primary biliary cirrhosis, and hepatitis-B-related hepatocellular carcinoma.

To discover susceptibility genes of late-onset Alzheimer's disease (LOAD), we conducted a 3-stage genome-wide association study (GWAS) using three populations: Japanese from the Japanese Genetic Consortium for Alzheimer Disease (JGSCAD), Koreans, and Caucasians from the Alzheimer Disease Genetic Consortium (ADGC). In Stage 1, we evaluated data for 5,877,918 genotyped and imputed SNPs in Japanese cases (n = 1,008) and controls (n = 1,016). Genome-wide significance was observed with 12 SNPs in the APOE region. Seven SNPs from other distinct regions with p-values <2×10(-5) were genotyped in a second Japanese sample (885 cases, 985 controls), and evidence of association was confirmed for one SORL1 SNP (rs3781834, P = 7.33×10(-7) in the combined sample). Subsequent analysis combining results for several SORL1 SNPs in the Japanese, Korean (339 cases, 1,129 controls) and Caucasians (11,840 AD cases, 10,931 controls) revealed genome wide significance with rs11218343 (P = 1.77×10(-9)) and rs3781834 (P = 1.04×10(-8)). SNPs in previously established AD loci in Caucasians showed strong evidence of association in Japanese including rs3851179 near PICALM (P = 1.71×10(-5)) and rs744373 near BIN1 (P = 1.39×10(-4)). The associated allele for each of these SNPs was the same as in Caucasians. These data demonstrate for the first time genome-wide significance of LOAD with SORL1 and confirm the role of other known loci for LOAD in Japanese. Our study highlights the importance of examining associations in multiple ethnic populations.