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:Gene expression profile at 12hr after common bile duct ligation. Hybridization was carried out four times including color swap to eliminate any dye bias. Keywords: repeat sample
Project description:Gene expression profile at 3hr after common bile duct ligation. Hybridization was carried out four times including color swap to eliminate any dye bias. Keywords: repeat sample
Project description:Gene expression profile at 1hr after common bile duct ligation. Hybridization was carried out four times including color swap to eliminate any dye bias. Keywords: repeat sample
Project description:Dynamic changes in growth factor expression is observed after bile duct ligation at different time points compared to sham-treated mice, corresponding to increase in biliary cell proliferation and repair
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:Background & Aims: Macrophages (MF) play a role in neonatal etiologies of obstructive cholestasis, however, the role for precise MF subsets remains poorly defined. We developed a neonatal murine model of bile duct ligation (BDL) to characterize etiology-specific differences in neonatal cholestatic MF polarization. Approach & Results: Neonatal BDL surgery was performed on female BALB/c mice at 10 days of life (DOL) with sham laparotomy as controls. Comparison was made to the Rhesus Rotavirus (RRV)-induced murine model of biliary atresia (BA). Evaluation of changes at day 7 after surgery (BDL and sham groups) and murine BA (DOL14) included laboratory data, histology (H&E, anti-CD45 and anti-CK19 staining), flow cytometry of MF subsets by MHCII and Ly6c expression, and single cell RNA-sequencing (scRNA-seq) analysis. Neonatal BDL achieved a 90% survival rate; mice had elevated bile acids, bilirubin, and alanine aminotransferase (ALT) versus controls (p < 0.05 for all). Histology demonstrated hepatocellular injury, CD45+ portal infiltrate, and CK19+ bile duct proliferation in neonatal BDL. Comparison to murine BA showed increased ALT in neonatal BDL despite no difference in histology Ishak score. Neonatal BDL had significantly lower MHCII-Ly6c+ MF versus murine BA, however, scRNA-seq identified greater etiology-specific MF heterogeneity with increased endocytosis in neonatal BDL MF versus cellular killing in murine BA MF. Conclusions: We generated an innovative murine model of neonatal obstructive cholestasis with low mortality. This model enabled comparison to murine BA to define etiology-specific cholestatic MF function. Further comparisons to human data may enable development of immune modulatory therapies to improve patient outcomes.