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Macrophage recruitment by fibrocystin-defective biliary epithelial cells promotes portal fibrosis in congenital hepatic fibrosis.

ABSTRACT: Congenital hepatic fibrosis (CHF) is a disease of the biliary epithelium characterized by bile duct changes resembling ductal plate malformations and by progressive peribiliary fibrosis, in the absence of overt necroinflammation. Progressive liver fibrosis leads to portal hypertension and liver failure; however, the mechanisms leading to fibrosis in CHF remain elusive. CHF is caused by mutations in PKHD1, a gene encoding for fibrocystin, a ciliary protein expressed in cholangiocytes. Using a fibrocystin-defective (Pkhd1(del4/del4)) mouse, which is orthologous of CHF, we show that Pkhd1(del4/del4) cholangiocytes are characterized by a ?-catenin-dependent secretion of a range of chemokines, including chemokine (C-X-C motif) ligands 1, 10, and 12, which stimulate bone marrow-derived macrophage recruitment. We also show that Pkhd1(del4/del4) cholangiocytes, in turn, respond to proinflammatory cytokines released by macrophages by up-regulating ?v?6 integrin, an activator of latent local transforming growth factor-?1. While the macrophage infiltrate is initially dominated by the M1 phenotype, the profibrogenic M2 phenotype increases with disease progression, along with the number of portal myofibroblasts. Consistent with these findings, clodronate-induced macrophage depletion results in a significant reduction of portal fibrosis and portal hypertension as well as of liver cysts.Fibrosis can be initiated by an epithelial cell dysfunction, leading to low-grade inflammation, macrophage recruitment, and collagen deposition; these findings establish a new paradigm for biliary fibrosis and represent a model to understand the relationship between cell dysfunction, parainflammation, liver fibrosis, and macrophage polarization over time.

SUBMITTER: Locatelli L

PROVIDER: S-EPMC4764460 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature

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Macrophage recruitment by fibrocystin-defective biliary epithelial cells promotes portal fibrosis in congenital hepatic fibrosis.

Locatelli Luigi L Cadamuro Massimiliano M Spirlì Carlo C Fiorotto Romina R Lecchi Silvia S Morell Carola Maria CM Popov Yury Y Scirpo Roberto R De Matteis Maria M Amenduni Mariangela M Pietrobattista Andrea A Torre Giuliano G Schuppan Detlef D Fabris Luca L Strazzabosco Mario M

Hepatology (Baltimore, Md.) 20160116 3

<h4>Unlabelled</h4>Congenital hepatic fibrosis (CHF) is a disease of the biliary epithelium characterized by bile duct changes resembling ductal plate malformations and by progressive peribiliary fibrosis, in the absence of overt necroinflammation. Progressive liver fibrosis leads to portal hypertension and liver failure; however, the mechanisms leading to fibrosis in CHF remain elusive. CHF is caused by mutations in PKHD1, a gene encoding for fibrocystin, a ciliary protein expressed in cholangi ...[more]

PMID: 26645994

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Project description:BackgroundIntrahepatic biliary fibrosis, as seen with cholestatic liver injuries such as biliary atresia, is mechanistically distinct from fibrosis caused by hepatocyte toxicity. We previously demonstrated the expansion of cells expressing the stem/progenitor cell marker Prominin-1, within regions of developing fibrosis in biliary atresia. Thus, we hypothesized that Prominin-1 expression is biliary fibrosis-specific.MethodsGene expression of Prominin-1 was analyzed in adult mice undergoing either cholestatic bile duct ligation or hepatotoxic carbon tetrachloride administration by quantitative polymerase chair reaction. Lineage tracing of Prominin-1-expressing cells and Collagen-1α-expressing cells was performed after bile duct ligation in Prominin-1cre-ert2-lacz;Gfplsl and Collagen-1αGfp transgenic mice, respectively.ResultsProminin-1 expression increased significantly after bile duct ligation compared with sham (6.6 ± 0.9-fold change at 2 weeks, P < .05) but not with carbon tetrachloride (-0.7 ± 0.5-fold change, not significant). Upregulation of Prominin-1 was observed histologically throughout the liver as early as 5 days after bile duct ligation in Prominin-1cre-ert2-lacz mice by LacZ staining in nonhepatocyte cells. Lineage tracing of Prominin-1-expressing cells labeled prior to bile duct ligation in Prominin-1cre-ert2-lacz;Gfplsl mice, demonstrated increasing colocalization of GREEN FLUORESCENT PROTEIN with biliary marker CYTOKERATIN-19 within ductular reactions up to 5 weeks after bile duct ligation consistent with biliary transdifferentiation. In contrast, rare colocalization of GREEN FLUORESCENT PROTEIN with mesenchymal marker α-SMOOTH MUSCLE ACTIN in Prominin-1cre-ert2-lacz;Gfplsl mice and some colocalization of GREEN FLUORESCENT PROTEIN with PROMININ-1 in Collagen-1αGfp mice, indicate minimal contribution of Prominin-1 progenitor cells to the pool of collagen-producing myofibroblasts.ConclusionDuring biliary fibrosis Prominin-1-expressing progenitor cells transdifferentiate into cells within ductular reactions. This transdifferentiation may promote fibrosis.

Project description:Placental growth factor (PlGF), a member of the vascular endothelial growth factor (VEGF) family, mediates wound healing and inflammatory responses, exerting an effect on liver fibrosis and angiogenesis; however, the precise mechanism remains unclear. The aims of this study are to identify the role of PlGF in liver inflammation and fibrosis induced by bile duct ligation (BDL) in mice and to reveal the underlying molecular mechanism. PlGF small interfering RNA (siRNA) or non-targeting control siRNA was injected by tail vein starting 2 days after BDL. Liver inflammation, fibrosis, angiogenesis, macrophage infiltration, and hepatic stellate cells (HSCs) activation were examined. Our results showed that PlGF was highly expressed in fibrotic livers and mainly distributed in activated HSCs and macrophages. Furthermore, PlGF silencing strongly reduced the severity of liver inflammation and fibrosis, and inhibited the activation of HSCs. Remarkably, PlGF silencing also attenuated BDL-induced hepatic angiogenesis, as evidenced by attenuated liver endothelial cell markers CD31 and von Willebrand factor immunostaining and genes or protein expression. Interestingly, these pathological ameliorations by PlGF silencing were due to a marked reduction in the numbers of intrahepatic F4/80+, CD68+, and Ly6C+ cell populations, which were reflected by a lower expression of these macrophage marker molecules in fibrotic livers. In addition, knockdown of PlGF by siRNA inhibited macrophages activation and substantially suppressed the expression of pro-inflammatory cytokines and chemokines in fibrotic livers. Mechanistically, evaluation of cultured RAW 264.7 cells revealed that VEGF receptor 1 (VEGFR1) mainly involved in mediating the role of PlGF in macrophages recruitment and activation, since using VEGFR1 neutralizing antibody blocking PlGF/VEGFR1 signaling axis significantly inhibited macrophages migration and inflammatory responses. Together, these findings indicate that PlGF plays an important role in liver inflammation, angiogenesis, and fibrosis by promoting hepatic macrophage recruitment and activation, and suggest that blockage of PlGF could be a promising novel therapy for chronic fibrotic liver diseases.

Project description:Chronic hepatic inflammation from multiple etiologies leads to a fibrogenic response that can progress to cirrhosis and liver failure. Transplantation of human amniotic epithelial cells (hAEC) from term delivered placenta has been shown to decrease mild to moderate hepatic fibrosis in a murine model. To model advanced human liver disease and assess the efficacy of hAEC therapy, we transplanted hAEC in mice with advanced hepatic fibrosis. Immunocompetent C57BL/6 mice were administered carbon tetrachloride (CCl(4)) twice weekly resulting in bridging fibrosis by 12 weeks. hAEC (2 × 10(6)) were infused via the tail vein at week 8 or weeks 8 and 10 (single and double dose, respectively). Human cells were detected in mouse liver four weeks after transplantation showing hAEC engraftment. CCl(4) treated mice receiving single or double hAEC doses showed a significant but similar decrease in liver fibrosis area associated with decreased activation of collagen-producing hepatic stellate cells and decreased hepatic protein levels of the pro-fibrogenic cytokine, transforming growth factor-beta1. CCl(4) administration caused hepatic T cell infiltration that decreased significantly following hAEC transplantation. Hepatic macrophages play a crucial role in both fibrogenesis and fibrosis resolution. Mice exposed to CCl(4) demonstrated increased numbers of hepatic macrophages compared to normal mice; the number of macrophages decreased significantly in CCl(4) treated mice given hAEC. These mice had significantly lower hepatic protein levels of the chemokine monocyte chemoattractant protein-1 than mice given CCl(4) alone. Alternatively activated M2 macrophages are associated with fibrosis resolution. CCl(4) treated mice given hAEC showed increased expression of genes associated with M2 macrophages including YM-1, IL-10 and CD206. We provide novel data showing that hAEC transplantation induces a wound healing M2 macrophage phenotype associated with reduction of established hepatic fibrosis that justifies further investigation of this potential cell-based therapy for advanced hepatic fibrosis.

Project description:We investigated noninvasive follow-up markers for histologic liver fibrosis and portal hypertension (PH) in patients with biliary atresia after successful portoenterostomy (PE). Among children with bilirubin <20 µmol/L after PE (n = 39), Metavir fibrosis stage was evaluated at PE and in follow-up protocol liver biopsies (n = 83). PH was defined as endoscopically confirmed esophageal varices or thrombocytopenia associated with splenomegaly. The accuracy of liver biochemistry and stiffness in detecting liver fibrosis and PH was analyzed by the area under the receiving operating characteristic curve (AUROC) and multiple regression models. During a median native liver survival of 8.3 years (interquartile range 2.5-10.8 years), cirrhosis (Metavir F4) had developed in 51% of patients and PH in 54% of patients. Cirrhosis was equally common in all age tertiles of 1.2-2.1 years (n = 10/27), 3.9-5.8 years (n = 12/28), and 9.0-14 years (n = 12/28). In the two oldest age tertiles, histologic liver fibrosis had progressed further in patients with PH than without PH (P < 0.001). PH was accurately predicted by the aspartate aminotransferase-to-platelet ratio index (APRI) (cutoff, 0.70; AUROC, 0.92), bile acids (cutoff, 49 µmol/L; AUROC, 0.91), and liver stiffness (cutoff, 16.9 kPa; AUROC, 0.89; P < 0.001 each) across all age tertiles. Liver stiffness was the most accurate predictor of cirrhosis overall (AUROC, 0.82; P < 0.001), whereas bilirubin was >11 µmol/L in the youngest tertile (AUROC, 0.91; P < 0.001), bile acids was >80 µmol/L in the middle tertile (AUROC, 0.81; P = 0.009), and liver stiffness was >24 kPa in the oldest age tertile (AUROC, 0.96; P = 0.002). Conclusion: After successful PE, development of PH associates with progression of liver fibrosis and can be accurately detected by APRI and stiffness. Liver stiffness most accurately identified cirrhosis in older children, whereas biochemical markers of cholestasis closely reflected histologic cirrhosis in younger children.

Project description:IntroductionIn some patients with congenital biliary dilation (CBD), biliary cirrhosis has been reported to rapidly progress from the neonatal period to the infantile period. We herein report an infantile case of CBD that showed severe biliary cirrhosis at the diagnosis, which was treated by laparoscopic surgery.Case presentationA 16-month-old girl underwent conservative therapy for liver dysfunction and cholangitis on a remote island of our prefecture. She was transferred to our hospital after the detection of a huge dilated common bile duct on imaging at the previous hospital. Contrast-enhanced computed tomography showed a dilated common bile duct (maximum diameter: 5 cm), thus suggesting CBD. However, her laboratory data on admission showed a poor nutritional status and severe liver dysfunction (Alb, 2.5 mg/dl; AST, 79 IU/L; ALT, 43 IU/L; γ-GTP, 491 mg/dl; D-bil, 0.3 mg/dl; CHE, 90 IU/L; NH3, 123 μg/dl). We initially performed laparoscopic exploration and bile drainage via the gallbladder, noting severe hepatic fibrosis resembling end-stage liver cirrhosis. After placing a drainage tube in the gallbladder, cholangiography was performed. Cholangiography showed Todani type IVa CBD with pancreaticobiliary maljunction. Contrast agent flowing into the duodenum could not be confirmed. The patient received liver-supporting therapy and nutritional support for 7 weeks before definitive surgery. Following the improvement of the hepatic synthetic capacity (Alb, 4.0 mg/dl; AST, 82 IU/L; ALT, 78 IU/L; γ-GTP, 157 mg/dl; D-bil, 0.2 mg/dl; CHE, 232 IU/L; NH3, 75 μg/dl), we performed extrahepatic bile duct excision and hepaticojejunostomy laparoscopically. Laparoscopic surgery was successfully performed along with liver biopsy. Histopathologically, the liver specimen showed chronic hepatitis and fibrosis (F3A2). Biliary scintigraphy showed good bile excretion at postoperative day 15. The postoperative course uneventful, and the patient was discharged on the 23rd day after surgery. A needle liver biopsy six months later showed mild improvement of chronic hepatitis and fibrosis (F2-3A1). The patient was regularly followed at the outpatient clinic.ConclusionsSevere liver fibrosis was suspected to be continuous cholestasis of CBD after birth. CBD with severe liver fibrosis may avoid liver transplantation by two-stage surgery with hepatoprotection therapy and immunonutritional support.

Dataset Information

Macrophage recruitment by fibrocystin-defective biliary epithelial cells promotes portal fibrosis in congenital hepatic fibrosis.

Publications

Macrophage recruitment by fibrocystin-defective biliary epithelial cells promotes portal fibrosis in congenital hepatic fibrosis.

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