Project description:Genome-wide association scan was performed in 1,840 cases of primary biliary cirrhosis and 5,163 controls. Replication of new associations was tested in an independent set of 620 cases and 2,514 controls.
Project description:<p>A Genome-wide association study of primary biliary cirrhosis (PBC) with an Italian cohort and loci meeting suggestive criteria were confirmed using a replication dataset from a previous Canadian study. The results confirmed associations for IL12A, IL12RB2, and HLA (peak between DQA1 and DQB1) and identified novel associations with IKZF3/ORMDL3 on chromosome 17, SPIB on chromosome 19, and IRF5 on chromosome. These studies also provided definition of haplotypic associations, differences between the PBC associated chromosome 17 haplotype and that of pediatric asthma and suggested several other genes as candidates for PBC susceptibility including DENND1B.</p>
Project description:Primary biliary cholangitis (PBC), formally known as primary biliary cirrhosis, is an autoimmune liver disease of unknown pathogenesis. Consequently, therapeutic targets for PBC have yet to be identified. As CD4+ T cells play a pivotal role in immunological dysfunction observed in PBC, we analyzed microRNA(miRNA) and mRNA expression in CD4+ T cells to investigate PBC pathogenesis and identify novel therapeutic targets.
Project description:2,981 primary biliary cirrhosis (PBC) cases were collected by the UK PBC Consortium and genotyped on the Illumina Immunochip where 2,861 passed quality control. These cases were then compared to a UK population control to identify novel PBC risk loci and fine-map association signals. (Liu & Almarri et al., Nat Genet, 2012)
Project description:Autoimmune regulator (Aire) and TGF-β signaling play an important role in central tolerance and peripheral tolerance respectively, by eliminating or suppressing the activity of autoreactive T cells. We have previously demonstrated that dnTGFβRII mice develop a defect in peripheral tolerance and a primary biliary cirrhosis (PBC) like disease. We hypothesized that by introducing the AIRE gene to this model, we would observe a more severe PBC phenotype. Interestingly, however, we demonstrate that while dnTGFβRII Aire-/- mice do manifest key histologic and serologic features of autoimmune cholangitis, they also develop mild to moderate interface hepatitis and show high levels of alanine transaminase (ALT) and antinuclear antibodies (ANA), characteristics of autoimmune hepatitis (AIH). To further understand this unique phenotype, we performed RNA-seq and flow cytometry to explore the functional pathways and immune cell pathways in the liver of dnTGFβRII Aire-/- mice. Our data revealed enrichments of programmed cell death pathways and predominant CD8+ T cell infiltrates. Depleting CD8+ T cells using an anti-CD8α antibody significantly alleviated hepatic inflammation and prolonged the lifespan of these mice. Finally, RNA-seq data indicated the clonal expansion of hepatic CD8+ T cells. In conclusion, these mice develop an autoreactive CD8+ T cell mediated autoimmune cholangitis with concurrent hepatitis that exhibits key histological and serological features of the AIH-PBC overlap syndrome, representing a novel model for the study of tolerance and autoimmune liver disease.
Project description:Primary biliary cholangitis (PBC), formally known as primary biliary cirrhosis, is an autoimmune liver disease of unknown pathogenesis. Consequently, therapeutic targets for PBC have yet to be identified. As CD4+ T cells play a pivotal role in immunological dysfunction observed in PBC, we analyzed microRNA(miRNA) and mRNA expression in CD4+ T cells to investigate PBC pathogenesis and identify novel therapeutic targets.
Project description:Primary biliary cirrhosis (PBC) is an immune-mediated chronic cholestatic liver disease with a slowly progressive course. Without treatment, most patients eventually develop fibrosis and cirrhosis of the liver and may need liver transplantation in the late stage of disease. PBC primarily affects women (female preponderance 9-10:1) with a prevalence of up to 1 in 1,000 women over 40 years of age. Common symptoms of the disease are fatigue and pruritus, but most patients are asymptomatic at first presentation. The diagnosis is based on sustained elevation of serum markers of cholestasis, i.e., alkaline phosphatase and gamma-glutamyl transferase, and the presence of serum antimitochondrial antibodies directed against the E2 subunit of the pyruvate dehydrogenase complex. Histologically, PBC is characterized by florid bile duct lesions with damage to biliary epithelial cells, an often dense portal inflammatory infiltrate and progressive loss of small intrahepatic bile ducts. Although the insight into pathogenetic aspects of PBC has grown enormously during the recent decade and numerous genetic, environmental, and infectious factors have been disclosed which may contribute to the development of PBC, the precise pathogenesis remains enigmatic. Ursodeoxycholic acid (UDCA) is currently the only FDA-approved medical treatment for PBC. When administered at adequate doses of 13-15 mg/kg/day, up to two out of three patients with PBC may have a normal life expectancy without additional therapeutic measures. The mode of action of UDCA is still under discussion, but stimulation of impaired hepatocellular and cholangiocellular secretion, detoxification of bile, and antiapoptotic effects may represent key mechanisms. One out of three patients does not adequately respond to UDCA therapy and may need additional medical therapy and/or liver transplantation. This review summarizes current knowledge on the clinical, diagnostic, pathogenetic, and therapeutic aspects of PBC.
Project description:In variceal bleeding liver function deterioration is a major cause of death. The effects of bleeding on intrahepatic microvascular dysfunction, which contributes to liver injury in cirrhosis, are largely unknown. The aims of this study were to evaluate the impact of hemorrhage/resuscitation (H/R) on cirrhotic microcirculation, and whether simvastatin, a drug that improves liver microcirculation, has hepatoprotective effects. The study was performed in three groups of rats: controls, rats with biliary cirrhosis (CBDL) and CBDL rats pre-treated with 3 doses (5 mg*Kg-1*day-1) of simvastatin. Rats were submitted to H/R or sham procedure. Subsequently, livers were isolated and perfused for functional assessment of liver microcirculation. Liver transcriptome was assessed with microarrays. H/R significantly impaired endothelial-dependent vasorelaxation in cirrhotic (p=0.035) but not control livers. H/R induced a similar increase in ALT in control and cirrhotic rats, whereas the increase in AST was 10 times higher in cirrhotic than in control rats (p=0.007). Simvastatin prevented the impairment in endothelial-dependent vasorelaxation induced by H/R, and reduced by half the increase in ALT and AST (p<0.05). Transcriptomics showed a marked upregulation of genes related to inflammatory response after H/R in cirrhotic livers, but not in controls, and this was blunted by simvastatin. In conclusion, H/R aggravates liver microvascular dysfunction in cirrhosis, and upregulates liver inflammatory pathways. This does not occur in control livers. Simvastatin prevented H/R-induced liver endothelial dysfunction, and attenuated liver injury and liver inflammatory response, suggesting that it might have potential for protecting the cirrhotic liver during bleeding complications.