Project description:<p>Maternal seeding of the microbiome in neonates promotes a long-lasting biological footprint, but how it impacts disease susceptibility in early life remains unknown. We hypothesized that feeding butyrate to pregnant mice influences the newborn’s susceptibility to biliary atresia, a severe cholangiopathy of neonates. Here, we show that butyrate administration to mothers renders newborn mice resistant to inflammation and injury of bile ducts and improves survival. The prevention of hepatic immune cell activation and survival trait is linked to fecal signatures of Bacteroidetes and Clostridia and increases glutamate/glutamine and hypoxanthine in stool metabolites of newborn mice. In human neonates with biliary atresia, the fecal microbiome signature of these bacteria is under-represented, with suppression of glutamate/glutamine and increased hypoxanthine pathways. The direct administration of butyrate or glutamine to newborn mice attenuates the disease phenotype, but only glutamine renders bile duct epithelial cells resistant to cytotoxicity by natural killer cells. Thus, maternal intake of butyrate influences the fecal microbial population and metabolites in newborn mice and the phenotypic expression of experimental biliary atresia, with glutamine promoting survival of bile duct epithelial cells.</p>
Project description:Background: RNASeq was performed on organoids derived from livers of normal healthy donors and patients with biliary atresia to characterize transcriptomic signatures. Methods: Organoids generated from livers of normal healthy donors and patients with biliary atresia were cultured either in expansion (undifferentiated: 3 NCOs and 11 BACOs) or differentiation medium (differentiated: 3 BACOs). Liver tissues obtained from deceased-donor subjects served as normal controls (N=3). Total RNA was isolated from organoids and liver biopsy tissue specimens. Results: Organoids from patients with biliary atresia showed abnormal cell polarity, loss of tight junctions, increased permeability and decreased expression of genes related to epidermal growth factor (EGF)- and fibroblast growth factor 2 (FGF2)-signaling. When treated with EGF+FGF2, biliary atresia organoids expressed differentiation and functional markers with restored cell polarity. Conclusion: Organoids from biliary atresia are viable and have evidence of halted epithelial development. The induction of developmental markers, improved cell‐cell junction, and decreased epithelial permeability by EGF and FGF2 identifies potential strategies to promote epithelial maturation and function.
Project description:BACKGROUND: Young age at portoenterostomy has been linked to improved outcome in biliary atresia, but pre-existing biological factors may influence the rate of disease progression. In this study, we aimed to determine whether molecular profiling of the liver identifies stages of disease at diagnosis. METHODS: We examined liver biopsies from 47 infants with biliary atresia enrolled in a prospective observational study. Biopsies were scored for inflammation and fibrosis, used for gene expression profiles, and tested for association with indicators of disease severity, response to surgery, and survival at 2 years. RESULTS: Fourteen of 47 livers displayed prominent features of inflammation (N=9) or fibrosis (N=5), with the remainder showing similar levels of both simultaneously. Differential profiling of gene expression of the 14 livers displayed a unique molecular signature containing 150 gene probes. Applying prediction analysis models, the probes classified 29 of the remaining 33 livers into inflammation or fibrosis. Molecular classification into the two groups was validated by the findings of increased hepatic population of lymphocyte subsets or tissue accumulation of matrix substrates. The groups had no association with traditional markers of liver injury or function, response to surgery, or complications of cirrhosis. However, infants with an inflammation signature were younger, while those with a fibrosis signature had decreased transplant-free survival. CONCLUSION: Molecular profiling at diagnosis of biliary atresia uncovers a signature of inflammation or fibrosis in most livers. This signature may relate to staging of disease at diagnosis and has implications to clinical outcomes. Clinical and laboratory data and liver biopies were obtained from 47 infants at diagnosis of biliary atresia and every 3-6 month intervals until 2 years of age as part of a prospective, observational study of the Biliary Atresia Research Consortium. Liver biopsies underwent histological scoring and those specimens classified as inflammation or fibrosis were used to generate a group-specific gene expression profile. The profile was used to assign a molecular stages of inflammation or fibrosis to the entire cohort. Molecular groups were tested for biological plausibility using immunostaining to quantify hepatic inflammatory cells, and quantitative PCR to reproduce the expression of gene groups and the expression of collagen genes. They were also tested for clinical relevance by testing of association with indicators of liver function, complications of disease, and clinical outcome. This dataset is part of the TransQST collection.
Project description:Biliary atresia (BA) is a progressive fibro-inflammatory disorder that is the leading indication for liver transplantation in children. Although there is evidence implicating genetic, infectious, environmental, and inflammatory causes, the etiology of BA remains unknown. We have recently reported that cholangiocytes from BA patients showed decreased DNA methylation relative to disease- and non-disease controls, supporting a potential role for DNA hypomethylation in BA etiopathogenesis. In the current study, we examined the methylation status of specific genes in human BA livers using methylation microarray technology. We found global DNA hypomethylation in BA samples as compared to disease- and non-disease controls at specific genetic loci. Hedgehog pathway members, SHH and GLI2, known to be upregulated in BA, were both hypomethylated, validating this approach as an investigative tool. Another region near the PDGFA locus was the most significantly hypomethylated in BA, suggesting potential aberrant expression. Validation assays confirmed increased transcriptional and protein expression of PDGFA in BA livers. We also show that PDGF-A protein is specifically localized to cholangiocytes in human liver samples. Injection of PDGF-AA protein dimer into zebrafish larvae caused biliary developmental and functional defects. In addition, activation of the Hedgehog pathway caused increased expression of PDGF-A in zebrafish larvae, providing a previously unrecognized link between PDGF and the Hedgehog pathway. DNA hypomethylation appears to be a specific factor in mediating overexpression of genes associated with BA. Our findings validate the role of Hedgehog pathway signaling and implicate PDGF as a new candidate for a role in BA pathogenesis.
Project description:Biliary atresia (BA) is a progressive fibro-inflammatory disorder that is the leading indication for liver transplantation in children. Although there is evidence implicating genetic, infectious, environmental, and inflammatory causes, the etiology of BA remains unknown. We have recently reported that cholangiocytes from BA patients showed decreased DNA methylation relative to disease- and non-disease controls, supporting a potential role for DNA hypomethylation in BA etiopathogenesis.
Project description:We report label-free quantification of xenobiotic metabolizing enzymes (XME), transporters, redox enzymes, proteases and nucleases in 25 human liver microsomal samples, taken from patients with biliary atresia. Nearly 3500 proteins were identified and quantified. These data can be used in physiologically based pharmacokinetic models to predict appropriate drug doses drugs used in biliary atresia patients.
Project description:BACKGROUND: Young age at portoenterostomy has been linked to improved outcome in biliary atresia, but pre-existing biological factors may influence the rate of disease progression. In this study, we aimed to determine whether molecular profiling of the liver identifies stages of disease at diagnosis. METHODS: We examined liver biopsies from 47 infants with biliary atresia enrolled in a prospective observational study. Biopsies were scored for inflammation and fibrosis, used for gene expression profiles, and tested for association with indicators of disease severity, response to surgery, and survival at 2 years. RESULTS: Fourteen of 47 livers displayed prominent features of inflammation (N=9) or fibrosis (N=5), with the remainder showing similar levels of both simultaneously. Differential profiling of gene expression of the 14 livers displayed a unique molecular signature containing 150 gene probes. Applying prediction analysis models, the probes classified 29 of the remaining 33 livers into inflammation or fibrosis. Molecular classification into the two groups was validated by the findings of increased hepatic population of lymphocyte subsets or tissue accumulation of matrix substrates. The groups had no association with traditional markers of liver injury or function, response to surgery, or complications of cirrhosis. However, infants with an inflammation signature were younger, while those with a fibrosis signature had decreased transplant-free survival. CONCLUSION: Molecular profiling at diagnosis of biliary atresia uncovers a signature of inflammation or fibrosis in most livers. This signature may relate to staging of disease at diagnosis and has implications to clinical outcomes.
Project description:Gene expression profile of biliary atresia at time of Kasai portoenterostomy was evaluated by comparing gene expression profile in biliary atresia and controls (choledochocyst).