transforming-growth-factor-beta and Bile-Duct-Diseases

To investigate the pathogenesis of a congenital form of hepatic fibrosis, human hepatic organoids were engineered to express the most common causative mutation for Autosomal Recessive Polycystic Kidney Disease (ARPKD). Here we show that these hepatic organoids develop the key features of ARPKD liver pathology (abnormal bile ducts and fibrosis) in only 21 days. The ARPKD mutation increases collagen abundance and thick collagen fiber production in hepatic organoids, which mirrors ARPKD liver tissue pathology. Transcriptomic and other analyses indicate that the ARPKD mutation generates cholangiocytes with increased TGFβ pathway activation, which are actively involved stimulating myofibroblasts to form collagen fibers. There is also an expansion of collagen-producing myofibroblasts with markedly increased PDGFRB protein expression and an activated STAT3 signaling pathway. Moreover, the transcriptome of ARPKD organoid myofibroblasts resemble those present in commonly occurring forms of liver fibrosis. PDGFRB pathway involvement was confirmed by the anti-fibrotic effect observed when ARPKD organoids were treated with PDGFRB inhibitors. Besides providing insight into the pathogenesis of congenital (and possibly acquired) forms of liver fibrosis, ARPKD organoids could also be used to test the anti-fibrotic efficacy of potential anti-fibrotic therapies.

Topics: Bile Duct Diseases; Collagen; Epithelial Cells; Humans; Induced Pluripotent Stem Cells; Liver; Liver Cirrhosis; Models, Biological; Mutation; Myofibroblasts; Organoids; Polycystic Kidney, Autosomal Recessive; Receptor, Platelet-Derived Growth Factor beta; Signal Transduction; STAT3 Transcription Factor; Transforming Growth Factor beta

Biliary atresia and paucity of intrahepatic bile ducts are the main causes of neonatal cholestasis leading to hepatic fibrosis. Fibrotic evolution is slow in paucity of bile ducts as compared to the rapid progression to biliary cirrhosis in biliary atresia when cholestasis persists despite hepatoportoenterostomy. Our aim was to compare the expression of collagens type I and IV, alpha-smooth muscle actin, osteonectin and transforming growth factor beta1 in biliary atresia and paucity of bile ducts.. Liver biopsies were obtained in 12 children with biliary atresia and in five with paucity of bile ducts. Collagens type I and IV, alpha-smooth muscle actin were detected with immunostaining. Collagens type I and IV, osteonectin and transforming growth factor beta1 mRNAs were detected by in situ hybridization.. Expression of mRNA and proteins was roughly parallel. In ductular proliferation areas of biliary atresia: (1) the expression of collagens type I and IV and osteonectin was increased, and was localized to periductular myofibroblasts; (2) transforming growth factor beta1 was expressed around biliary ductules, probably in inflammatory cells, and also in biliary cells. Osteonectin expression was also increased in the lobules. In paucity of bile ducts, there was no overexpression of collagens type I and IV and transforming growth factor beta1, except in the only child with marked fibrosis. However, osteonectin expression was enhanced at the periphery of the lobules, even when fibrosis was mild or absent.. These findings suggest that in biliary atresia ductular proliferation areas are the site of a marked production of extracellular matrix proteins in periductular myofibroblasts, probably secondary to transforming growth factor beta1 production by inflammatory cells and by biliary cells. The weak expression of transforming growth factor beta1 could explain the slow progression of fibrosis in paucity of bile ducts.

Topics: Actins; Bile Duct Diseases; Bile Ducts, Intrahepatic; Biliary Atresia; Collagen; Female; Humans; Immunohistochemistry; In Situ Hybridization; Infant; Infant, Newborn; Infant, Newborn, Diseases; Male; Muscle, Smooth, Vascular; Osteonectin; RNA, Messenger; Transforming Growth Factor beta

Some monocytic cytokines are important immune regulators. We have investigated cytokine production by monocytes and the blood levels of IL-1 beta, IL-6, TNF alpha, and TGF beta, in patients with obstructive jaundice. The supernatant from LPS stimulated monocytes from jaundiced patients released significantly increased quantities of TNF alpha by both bioassay and radioimmunoassay (RIA) (12.4 +/- 2.5 fmol/mL and 32.6 +/- 8.3 fmol/mL, respectively, for jaundice, compared with 1.6 +/- 0.3 fmol/mL and 2.4 +/- 0.5 fmol/mL respectively for controls, and also of IL-6 (54.8 +/- 5.0 fmol/mL in jaundice compared with 35.6 +/- 5.0 fmol/mL for controls). The production of IL-1 beta and TGF beta by stimulated monocytes was unchanged. Jaundiced patients had significantly higher plasma TGF beta, but TNF alpha and IL-1 beta were below the limits of detection. The highest monocyte TNF alpha and IL-6 levels were seen in malignant disease patients, especially those with a poor immediate prognosis. We conclude that the production of some cytokines by monocytes is up-regulated in patients with obstructive jaundice.

Topics: Bile Duct Diseases; Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Case-Control Studies; Cholangiocarcinoma; Cholelithiasis; Cholestasis; Cytokines; Female; Humans; Interleukin-1; Interleukin-6; Male; Middle Aged; Monocytes; Pancreatic Neoplasms; Prognosis; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Up-Regulation

These studies investigate the role of transforming growth factor-beta 1, a potent inhibitor of epithelial cell proliferation and stimulator of extracellular matrix biosynthesis, during intrahepatic bile duct hyperplasia and biliary fibrosis. These pathogenic responses were induced in rats by common bile duct ligation. Bile duct cell replication, measured by the bromodeoxyuridine labeling index, was significantly increased 24 hr after common bile duct ligation. This response diminished to baseline by 1 wk. Liver collagen content, determined by quantification of hydroxyproline, was increased significantly after 1 wk of common bile duct ligation, and by 4 wk was increased by a factor of 4. Immunohistochemistry revealed low levels of TGF-beta 1 in normal intrahepatic bile duct epithelium. In contrast, the bile duct epithelium in bile duct-ligated rats stained strongly positive for transforming growth factor-beta 1 at 1 and 4 wk after ligation. These results suggest that transforming growth factor-beta 1 may play a role in both the termination of the bile duct epithelial cell proliferative response and the induction of fibrogenesis after common bile duct ligation. In addition, the mannose 6-phosphate/insulin-like growth factor II receptor was up-regulated in hyperplastic bile duct epithelium 1 and 4 wk after ligation. Because the mannose 6-phosphate/insulin-like growth factor-II receptor has been shown to facilitate the proteolytic activation of transforming growth factor-beta 1, these results suggest that the bile duct epithelium may also be involved in the activation of transforming growth factor-beta 1.

Topics: Animals; Bile Duct Diseases; Bile Ducts, Intrahepatic; Common Bile Duct; DNA; Fibrosis; Hydroxyproline; Hyperplasia; Immunohistochemistry; Ligation; Liver; Male; Rats; Rats, Sprague-Dawley; Receptor, IGF Type 2; Transforming Growth Factor beta