Yoko Nakamura

Anti‐gp210 and anti‐centromere antibodies are different risk factors for the progression of primary biliary cirrhosis

The predictive role of antinuclear antibodies (ANAs) remains elusive in the long‐term outcome of primary biliary cirrhosis (PBC). The progression of PBC was evaluated in association with ANAs using stepwise Cox proportional hazard regression and an unconditional stepwise logistic regression model based on the data of 276 biopsy‐proven, definite PBC patients who have been registered to the National Hospital Organization Study Group for Liver Disease in Japan (NHOSLJ). When death of hepatic failure/liver transplantation (LT) was defined as an end‐point, positive anti‐gp210 antibodies (Hazard ratio (HR) = 6.742, 95% confidence interval (CI): 2.408, 18.877), the late stage (Scheuers stage 3, 4) (HR = 4.285, 95% CI:1.682,10.913) and male sex (HR = 3.266, 95% CI: 1.321,8.075) were significant risk factors at the time of initial liver biopsy. When clinical progression to death of hepatic failure/LT (i.e., hepatic failure type progression) or to the development of esophageal varices or hepatocellular carcinoma without developing jaundice (Total bilirubin < 1.5 mg/dL) (i.e., portal hypertension type progression) was defined as an end‐point in the early stage (Scheuers stage 1, 2) PBC patients, positive anti‐gp210 antibodies was a significant risk factor for hepatic failure type progression [odds ratio (OR) = 33.777, 95% CI: 5.930, 636.745], whereas positive anti‐centromere antibodies was a significant risk factor for portal hypertension type progression (OR = 4.202, 95% CI: 1.307, 14.763). Histologically, positive anti‐gp210 antibodies was most significantly associated with more severe interface hepatitis and lobular inflammation, whereas positive anticentromere antibodies was most significantly associated with more severe ductular reaction. Conclusion: These results indicate 2 different progression types in PBC, hepatic failure type and portal hypertension type progression, which may be represented by positive‐anti‐gp210 and positive‐anticentromere antibodies, respectively. (HEPATOLOGY 2007;45:118–127.)

A functional deficiency of TERA/VCP/p97 contributes to impaired DNA repair in multiple polyglutamine diseases.

It is hypothesized that a common underlying mechanism links multiple neurodegenerative disorders. Here we show that transitional endoplasmic reticulum ATPase (TERA)/valosin-containing protein (VCP)/p97 directly binds to multiple polyglutamine disease proteins (huntingtin, ataxin-1, ataxin-7 and androgen receptor) via polyglutamine sequence. Although normal and mutant polyglutamine proteins interact with TERA/VCP/p97, only mutant proteins affect dynamism of TERA/VCP/p97. Among multiple functions of TERA/VCP/p97, we reveal that functional defect of TERA/VCP/p97 in DNA double-stranded break repair is critical for the pathology of neurons in which TERA/VCP/p97 is located dominantly in the nucleus in vivo. Mutant polyglutamine proteins impair accumulation of TERA/VCP/p97 and interaction of related double-stranded break repair proteins, finally causing the increase of unrepaired double-stranded break. Consistently, the recovery of lifespan in polyglutamine disease fly models by TERA/VCP/p97 corresponds well to the improvement of double-stranded break in neurons. Taken together, our results provide a novel common pathomechanism in multiple polyglutamine diseases that is mediated by DNA repair function of TERA/VCP/p97.

Genetic polymorphisms in CTLA4 and SLC4A2 are differentially associated with the pathogenesis of primary biliary cirrhosis in Japanese patients

BackgroundAnti-gp210 and anti-centromere antibodies are different risk factors for the progression of primary biliary cirrhosis (PBC). In order to dissect the genetic basis for the production of these autoantibodies, as well as the development and progression of PBC in Japanese patients, we examined single nucleotide polymorphisms (SNPs) in cytotoxic T-lymphocyte antigen 4 (CTLA4) and solute carrier family 4 anion exchanger, member 2 (SLC4A2), which have been associated with the pathogenesis of PBC in Caucasian patients.MethodsFour SNPs for both CTLA4 and SLC4A2 were genotyped, using the polymerase chain reaction–restriction fragment length polymorphism method and TaqMan assay, in 450 Japanese PBC patients and 371 sex-matched healthy controls.ResultsThe CTLA4 rs231775, rs3087243, and rs231725 SNPs were significantly associated with PBC susceptibility. The CTLA4 rs231725 SNP was significantly associated with progression to late-stage disease. The CTLA-4 haplotype 1 (rs231775 G, rs231777 C, rs3087243 G, rs231725 A; GCGA) was a risk factor for PBC susceptibility but a protective factor for PBC progression. Conversely, the CTLA-4 haplotype 2 (ACAG) was a protective and risk factor, respectively, for PBC susceptibility and progression. In addition, the CTLA4 rs231777 SNP and haplotype 3 (ATGG) was significantly associated with anti-gp210 antibody production, while SLC4A2 haplotype 4 (rs2069443 A, rs2303933 G, rs2303937 A, rs2303941 T; AGAT) and haplotype 3 (AAGC) were significantly associated with PBC susceptibility and anti-centromere antibody production, respectively.ConclusionsCTLA4 and SLC4A2 genetic polymorphisms are differentially associated with PBC development and progression, as well as anti-gp210 or anti-centromere antibody production, in Japanese PBC patients.

Hepatocellular carcinoma and survival in patients with autoimmune hepatitis (Japanese National Hospital Organization-autoimmune hepatitis prospective study)

Although the outcome of autoimmune hepatitis (AIH) is generally good, the natural course and likelihood of progression to cirrhosis or hepatocellular carcinoma (HCC) remain undefined, and may vary by region and population structure. Our aims were to evaluate risk factors that contribute to poor outcome and particularly development of HCC in a prospective multicentric cohort study of AIH.

Ataxin-7 associates with microtubules and stabilizes the cytoskeletal network

The spinocerebellar ataxia type 7 (SCA7) gene product, Ataxin-7 (ATXN7), localizes to the nucleus and has been shown to function as a component of the TATA-binding protein-free TAF-containing-SPT3-TAF9-GCN5-acetyltransferase transcription complex, although cytoplasmic localization of ATXN7 in affected neurons of human SCA7 patients has also been detected. Here, we define a physiological function for cytoplasmic ATXN7. Live imaging reveals that the intracellular distribution of ATXN7 dynamically changes and that ATXN7 distribution frequently shifts from the nucleus to the cytoplasm. Immunocytochemistry and immunoprecipitation demonstrate that cytoplasmic ATXN7 associates with microtubules (MTs), and expression of ATXN7 stabilizes MTs against nocodazole treatment, while ATXN7 knockdown enhances MT degradation. Interestingly, normal and mutant ATXN7 similarly associate with and equally stabilize MTs. Taken together, these findings provide a novel physiological function of ATXN7 in the regulation of cytoskeletal dynamics, and suggest that abnormal cytoskeletal regulation may contribute to SCA7 disease pathology.

Circulating microRNA Profiles in Patients with Type-1 Autoimmune Hepatitis

Recent studies have demonstrated that micro (mi)RNA molecules can be detected in the circulation and can serve as potential biomarkers of various diseases. This study used microarray analysis to identify aberrantly expressed circulating miRNAs in patients with type 1 autoimmune hepatitis (AIH) compared with healthy controls. Patients with well-documented and untreated AIH were selected from the National Hospital Organization (NHO)-AIH-liver-network database. They underwent blood sampling and liver biopsy with inflammation grading and fibrosis staging before receiving treatment. To further confirm the microarray data, circulating expression levels of miR-21 and miR-122 were quantified by real-time quantitative polymerase chain reaction in 46 AIH patients, 40 patients with chronic hepatitis C (CHC), and 13 healthy controls. Consistent with the microarray data, serum levels of miR-21 were significantly elevated in AIH patients compared with CHC patients and healthy controls. miR-21 and miR-122 serum levels correlated with alanine aminotransferase levels. Circulating levels of miR-21 and miR-122 were significantly reduced in AIH patients with liver cirrhosis, and were inversely correlated with increased stages of fibrosis. By contrast, levels of circulating miR-21 showed a significant correlation with the histological grades of inflammation in AIH. We postulate that aberrantly expressed serum miRNAs are potential biomarkers of AIH and could be implicated in AIH pathogenesis. Alternations of miR-21 and miR-122 serum levels could reflect their putative roles in the mediation of inflammatory processes in AIH.

Association of STAT4 Polymorphisms with Susceptibility to Type-1 Autoimmune Hepatitis in the Japanese Population

Background/Aims Recent studies demonstrated an association of STAT4 polymorphisms with autoimmune diseases including systemic lupus erythematosus and rheumatoid arthritis, indicating multiple autoimmune diseases share common susceptibility genes. We therefore investigated the influence of STAT4 polymorphisms on the susceptibility and phenotype of type-1 autoimmune hepatitis in a Japanese National Hospital Organization (NHO) AIH multicenter cohort study. Methodology/Principal Findings Genomic DNA from 460 individuals of Japanese origin including 230 patients with type-1 autoimmune hepatitis and 230 healthy controls was analyzed for two single nucleotide polymorphisms in the STAT4 gene (rs7574865, rs7582694). The STAT4 rs7574865T allele conferred risk for type-1 autoimmune hepatitis (OR = 1.61, 95% CI = 1.23–2.11; P = 0.001), and patients without accompanying autoimmune diseases exhibited an association with the rs7574865T allele (OR = 1.50, 95%CI = 1.13–1.99; P = 0.005). Detailed genotype-phenotype analysis of type-1 autoimmune hepatitis patients with (n = 44) or without liver cirrhosis (n = 186) demonstrated that rs7574865 was not associated with the development of liver cirrhosis and phenotype (biochemical data and the presence of auto-antibodies). Conclusions/Significance This is the first study to show a positive association between a STAT4 polymorphism and type-1 autoimmune hepatitis, suggesting that autoimmune hepatitis shares a gene commonly associated with risk for other autoimmune diseases.

Genome-wide association studies identify PRKCB as a novel genetic susceptibility locus for primary biliary cholangitis in the Japanese population

&NA; A previous genome‐wide association study (GWAS) performed in 963 Japanese individuals (487 primary biliary cholangitis [PBC] cases and 476 healthy controls) identified TNFSF15 (rs4979462) and POU2AF1 (rs4938534) as strong susceptibility loci for PBC. In this study, we performed GWAS in additional 1,923 Japanese individuals (894 PBC cases and 1,029 healthy controls), and combined the results with the previous data. This GWAS, together with a subsequent replication study in an independent set of 7,024 Japanese individuals (512 PBC cases and 6,512 healthy controls), identified PRKCB (rs7404928) as a novel susceptibility locus for PBC (odds ratio [OR] = 1.26, P = 4.13 × 10‐9). Furthermore, a primary functional variant of PRKCB (rs35015313) was identified by genotype imputation using a phased panel of 1,070 Japanese individuals from a prospective, general population cohort study and subsequent in vitro functional analyses. These results may lead to improved understanding of the disease pathways involved in PBC, forming a basis for prevention of PBC and development of novel therapeutics.

Analyzing the possible involvement of anti-Müllerian hormone and anti-Müllerian hormone receptor II single nucleotide polymorphism in infertility

PurposeWe performed TaqMan genotyping assays of anti-Mullerian hormone (AMH) and anti-Mullerian hormone receptor type II (AMHRII) single nucleotide polymorphisms (SNPs) in order to investigate how their frequency and distribution affect infertility treatment outcome.MethodsEighty Japanese women (advanced age: n = 51, endometriosis: n = 18, male infertility as a control: n = 11) who undertook ART were included in the study, and all couples underwent a full infertility investigation protocol. In order to investigate the natural distribution of SNPs, a naturally pregnant group of 28 subjects was recruited from among women who conceived naturally and subsequently delivered in our department. Genomic DNA was extracted from peripheral blood and genotyping was conducted by TaqMan genotyping assay. The relationship of AMH and AMHRII SNPs and treatment outcome in infertile women. Comparison of allele and genotype frequencies of infertile patients with naturally pregnant women.ResultsAMHRII −482 A>G homozygote mutation was complicated with ISV 5–6 C>T homozygote mutation and showed a significantly lower oocyte retrieval rate compared with a wild type. Two of 3 cases of AMHRII −482 A>G homozygote mutation were poor responders, and the distribution and frequency of each allele of naturally pregnant women showed no statistical difference compared with infertile women.ConclusionsThis study revealed the possible involvement of AMHRII −482 A>G polymorphism on the malfunction of follicular development in Japanese women.

A Low-Testosterone State Associated with Endometrioma Leads to the Apoptosis of Granulosa Cells

Although endometriosis is suspected to be a cause of premature ovarian insufficiency (POI), the mechanism(s) underlying this process have not been elucidated. Recently, androgens were shown to promote oocyte maturation and to play a role in folliculogenesis. In addition, several reports have documented low testosterone levels in the follicular fluid obtained from endometriosis patients. We therefore examined whether the low levels of serum testosterone are associated with the apoptosis of granulosa cells in follicles obtained from endometriosis patients. Serum samples were collected from 46 patients with endometriosis and from 62 patients without endometriosis who received assisted reproductive therapy. Specimens of the ovaries obtained from 10 patients with endometrioma were collected using laparoscopy. The mean serum testosterone concentration in the patients with endometriosis was significantly lower than that observed in the patients without endometriosis. Furthermore, high expression of a pro-apoptotic Bcl-2 member, BimEL, in the follicles was found to be associated with a low serum testosterone level. We clarified the underlying mechanisms using a basic approach employing human immortalized granulosa cells derived from a primary human granulosa cell tumor, the COV434 cell line. The in vitro examination demonstrated that testosterone inhibited apoptosis induced by sex steroids depletion via the PI3K/Akt-FoxO3a pathway in the COV434 cells. In conclusion, we elucidated the mechanism underlying the anti-apoptotic effects of testosterone on granulosa cells, and found that a low-testosterone status is a potentially important step in the development of premature ovarian insufficiency in patients with endometriosis.