ABSTRACT: To investigate the differential gene expression of m6A RNA methylation in cholestatic liver fibrosis, we extablished a mouse model of liver fibrosis by common bile duct ligation.
Project description:The aim is to characterize rat liver fibrosis induced by bile duct ligation (BDL). To induce hepatic fibrosis, Male Sprague Dawley rats (9-12 weeks of age and 380-420 g of weight upon arrival, supplied by Beijing Vital River laboratory animal Co., Ltd.) underwent surgery of bile duct ligation (BDL). The bile ducts of Sprague-Dawley rats were ligated after 12 hours of fasting and water deprivation. Rat liver samples were collected from three groups of rats at week 1, 2 and 5 after BDL surgery. Three control groups of rats underwent sham operation, including bile duct mobilization, but without BDL. Three biological replicates were used for each group.
Project description:Extrahepatic cholestasis leads to complex injury and repair processes that result in bile infarct formation, neutrophil infiltration, cholangiocyte and hepatocyte proliferation, extracellular matrix remodeling, and fibrosis. To identify early molecular mechanisms of injury and repair after bile duct obstruction, microarray analysis was performed on liver tissue 24 hours after bile duct ligation (BDL) or sham surgery. The most upregulated gene identified encodes plasminogen activator inhibitor 1 (PAI-1, Serpine 1), a protease inhibitor that blocks urokinase plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) activity. Because PAI-1, uPA, and tPA influence growth factor and cytokine processing as well as extracellular matrix remodeling, we evaluated the role of PAI-1 in cholestatic liver injury by comparing the injury and repair processes in wild-type (WT) and PAI-1-deficient (PAI-1-/-) mice after BDL. PAI-1-/- mice had fewer and smaller bile infarcts, less neutrophil infiltration, and higher levels of cholangiocyte and hepatocyte proliferation than WT animals after BDL. Furthermore, PAI-1-/- mice had higher levels of tPA activation and mature hepatocyte growth factor (HGF) after BDL than WT mice, suggesting that PAI-1 effects on HGF activation critically influence cholestatic liver injury. This was further supported by elevated levels of c-Met and Akt phosphorylation in PAI-1-/- mice after BDL. In conclusion, PAI-1 deficiency reduces liver injury after BDL in mice. These data suggest that inhibiting PAI-1 might attenuate liver injury in cholestatic liver diseases. Total RNA isolated using TRI Reagent (Sigma, St. Louis, MO) was purified with an RNeasy mini kit (Qiagen, Valencia, CA). Twenty micrograms cRNA was hybridized to a mouse GeneChip (U74Av2, Affymetrix, Santa Clara, CA) at the Siteman Cancer Center GeneChip facility as described by the manufacturer. Analyses used one mouse per chip. Gene expression changes were analyzed using Affymetrix MicroArray Suite 4.0 and GeneChip 3.1 Expression Analysis and Statistical Algorithms (Affymetrix). The complete methodology and full data sets for all 6 analyzed chips are available at http://bioinformatics.wustl.edu.beckerproxy.wustl.edu This study compares the injury and repair processed in wild-type mice after BDL.
Project description:Extrahepatic cholestasis leads to complex injury and repair processes that result in bile infarct formation, neutrophil infiltration, cholangiocyte and hepatocyte proliferation, extracellular matrix remodeling, and fibrosis. To identify early molecular mechanisms of injury and repair after bile duct obstruction, microarray analysis was performed on liver tissue 24 hours after bile duct ligation (BDL) or sham surgery. The most upregulated gene identified encodes plasminogen activator inhibitor 1 (PAI-1, Serpine 1), a protease inhibitor that blocks urokinase plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) activity. Because PAI-1, uPA, and tPA influence growth factor and cytokine processing as well as extracellular matrix remodeling, we evaluated the role of PAI-1 in cholestatic liver injury by comparing the injury and repair processes in wild-type (WT) and PAI-1-deficient (PAI-1-/-) mice after BDL. PAI-1-/- mice had fewer and smaller bile infarcts, less neutrophil infiltration, and higher levels of cholangiocyte and hepatocyte proliferation than WT animals after BDL. Furthermore, PAI-1-/- mice had higher levels of tPA activation and mature hepatocyte growth factor (HGF) after BDL than WT mice, suggesting that PAI-1 effects on HGF activation critically influence cholestatic liver injury. This was further supported by elevated levels of c-Met and Akt phosphorylation in PAI-1-/- mice after BDL. In conclusion, PAI-1 deficiency reduces liver injury after BDL in mice. These data suggest that inhibiting PAI-1 might attenuate liver injury in cholestatic liver diseases.
Project description:Purpose: Cholestatic liver injury is associated with intrahepatic biliary fibrosis, which can progress to cirrhosis. Resident hepatic progenitor cells (HPCs) expressing Prominin-1 (Prom1/CD133) become activated and participate in the expansion of cholangiocytes known as the ductular reaction. Previously, we demonstrated that in biliary atresia, Prom1(+) HPCs are present within developing fibrosis and that null mutation of Prom1 significantly abrogates fibrogenesis. Here, we hypothesized that these activated Prom1-expressing HPCs promote fibrogenesis in cholestatic liver injury. Methods: Using Prom1CreERT2-nLacZ/+;Rosa26Lsl-GFP/+ mice, we traced the fate of Prom1-expressing HPCs in the growth of the neonatal and adult livers and in biliary fibrosis induced by bile duct ligation (BDL). Results: Prom1-expressing cell lineage labeling with Green Fluorescent Protein (GFP) on postnatal day 1 exhibited an expanded population as well as bipotent differentiation potential towards both hepatocytes and cholangiocytes at postnatal day 35. However, in the adult liver, they lost hepatocyte differentiation potential. Upon cholestatic liver injury, adult Prom1-expressing HPCs gave rise to both PROM1(+) and PROM1(-) cholangiocytes contributing to ductular reaction without hepatocyte or myofibroblast differentiation. RNA-sequencing analysis of GFP(+) Prom1-expressing HPC lineage revealed a persistent cholangiocyte phenotype and evidence of Transforming Growth Factor-b pathway activation. Conclusion: Our data indicate that Prom1-expressing HPCs promote biliary fibrosis by activation of myofibroblasts in cholestatic liver injury.
Project description:The collagen in cod fish skin has anti-inflammatory, anti-fibrotic, and protective effects on the liver and gut. However, the mechanism by which low molecular weight collagen peptides (LMW-CP) derived from cod fish skin protect against cholestatic liver fibrosis remains unclear. Therefore, this study evaluated the effect of LMW-CP on cholestatic liver fibrosis and explored its impact on bile stasis.
Project description:Liver fibrosis is a common pathological complication of end-stage liver disease, which is usually associated with chronic liver inflammation and injury. Liver fibrosis was induced by bile duct ligation (BDL) in rats. The differentially expressed genes in liver tissue of BDL rats were identified by microarray technique.
Project description:This experiment aims to determine the transcriptomic alteration in liver lympahtic endothelial cell (LyEC) in response to bile duct ligation (BDL)-induced cholestatic injury, which known to produce severe form of fibrosis and cirrhosis. We uncover a transcriptomic changes in LyEC associated with early-stage fibrosis/cirrhosis and late-stage decompensated liver cirrhosis. This work determines the functional change in lymphatic vessels and provides background necessary to discover therapeutic targets for improving LyEC function in the progression of liver diseases.
Project description:Huang-Lian-Jie-Du-Decoction, a traditional Chinese formula, has been reported to protect liver from various injuries. Two cholestasis models of rats induced by thioacetamide and by bile duct ligation were established and treated with Huang-Lian-Jie-Du-Decoction. Nuclear Magnetic Resonance-based urinary metabolic profiles were analyzed by orthogonal partial least squares discriminant analysis and univariate analysis to excavate differential metabolites associated with the injuries of the two models and the treatment effects of Huang-Lian-Jie-Du-Decoction. The two cholestatic models shared common metabolic features of excessive fatty acid oxidation, insufficient glutathione regeneration and disturbed gut flora, with specific characteristics of inhibited urea cycle and DNA damage in thioacetamide-intoxicated model, and perturbed Kreb's cycle and inhibited branched chain amino acid oxidation in bile duct ligation model. With good treatment effects, Huang-Lian-Jie-Du-Decoction could regain the balance of the disturbed metabolic status common in the two cholestasis injuries, e.g., unbalanced redox system and disturbed gut flora; and perturbed urea cycle in thioacetamide-intoxicated model and energy crisis (disturbed Kreb's cycle and oxidation of branched chain amino acid) in bile duct ligation model, respectively.
Project description:Animal models of parenchymal liver injury by bile duct ligation (BDL) and all forms of liver diseases including neonatal hepatitis and clinical obstructive cholangiopathies such as biliary atresia have the pathological features of cholestasis and liver dysfunction. Hepatocyte nuclear factors 6 (HNF6) is important to the transcriptional regulation, expression and function of essential hepatic genes involved in the differentiated as well as the adaptive response to liver injury. Using HNF6 conditional knock out mice where HNF6 is functionally deleted in the liver, we established that HNF6 is required for proper liver function of cholesterol clearance, improvement of cholestasis and hepatocyte regeneration. Enhancing HNF6 expression in wild type mice also diminished hepatic apoptosis and fibrosis. In this proposal, we propose to further characterize the biological function of HNF6 by testing the HYPOTHESIS that HNF6 direct transcriptional regulation of antiapoptotic and antifibrotic pathways contributes to hepatoprotection during bile duct injury. This hypothesis will be tested in two specific aims.
Project description:Cholestasis is characterized by hepatic accumulation of cytotoxic bile acids (BAs), which often subsequentlyleads to liver injury, inflammation, fibrosis, and ultimately liver cirrhosis. Fibroblast growth factor 21 (FGF21) is a liver secreted hormone with pleiotropic effects on the homeostasis of glucose, lipid, and energy metabolism. However, whether hepatic FGF21 plays a role in cholestatic liver injury remains elusive. We found that serum and hepatic FGF21 levels were significantly increased in response to cholestatic liver injury. Hepatocyte-specific deletion of Fgf21 exacerbated hepatic accumulation of BAs, further accentuating liver injury. Consistently, administration of rFGF21 ameliorated cholestatic liver injury in α-naphthylisothiocyanate (ANIT)-treated and Mdr2 deficiency mice. Mechanically, FGF21 activated a hepatic FGFR4-JNK signaling pathway to decrease Cyp7a1 expression, thereby reducing hepatic BAs pool. Our study demonstrates that hepatic FGF21 functions as an adaptive stress-responsive signal to downregulate BA biosynthesis, thereby ameliorating cholestatic liver injury, and FGF21 analogs may represent a candidate therapy for cholestatic liver diseases.