ADAM10 and ADAM17 are proteases that affect multiple signalling pathways by releasing molecules from the cell surface. As their substrate specificities partially overlaps, we investigated their concurrent role in liver regeneration and fibrosis, using three liver-specific deficient mouse lines: ADAM10- and ADAM17-deficient lines, and a line deficient for both proteases. In the model of partial hepatectomy, double deficient mice exhibited decreased AKT phosphorylation, decreased release of EGFR activating factors and lower shedding of HGF receptor c-Met. Thus, simultaneous ablation of ADAM10 and ADAM17 resulted in inhibited EGFR signalling, while HGF/c-Met signalling pathway was enhanced. In contrast, antagonistic effects of ADAM10 and ADAM17 were observed in the model of chronic CCl4 intoxication. While ADAM10-deficient mice develop more severe fibrosis manifested by high ALT, AST, ALP and higher collagen deposition, combined deficiency of ADAM10 and ADAM17 surprisingly results in comparable degree of liver damage as in control littermates. Therefore, ADAM17 deficiency is not protective in fibrosis development per se, but can ameliorate the damaging effect of ADAM10 deficiency on liver fibrosis development. Furthermore, we show that while ablation of ADAM17 resulted in decreased shedding of TNF RI, ADAM10 deficiency leads to increased levels of soluble TNF RI in serum. In conclusion, hepatocyte-derived ADAM10 and ADAM17 are important regulators of growth receptor signalling and TNF RI release, and pathological roles of these proteases are dependent on the cellular context.

• MeSH
• Fibrosis metabolism   MeSH
• Liver * metabolism   pathology   MeSH
• Cells, Cultured MeSH
• Membrane Proteins physiology   MeSH
• Mice, Inbred C57BL MeSH
• Mice MeSH
• Liver Diseases * metabolism   pathology   MeSH
• Primary Cell Culture MeSH
• ADAM10 Protein physiology   MeSH
• ADAM17 Protein physiology   MeSH
• Liver Regeneration * MeSH
• Amyloid Precursor Protein Secretases physiology   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Adam10 protein, mouse MeSH Browser
• Adam17 protein, mouse MeSH Browser
• Membrane Proteins MeSH
• ADAM10 Protein MeSH
• ADAM17 Protein MeSH
• Amyloid Precursor Protein Secretases MeSH

Matrix metalloproteinases (MMPs) are potential biomarkers for disease activity in inflammatory bowel disease (IBD). However, clinical trials targeting MMPs have not succeeded, likely due to poor understanding of the biological functions of individual MMPs. Here, we explore the role of MMP-19 in IBD pathology. Using a DSS-induced model of colitis, we show evidence for increased susceptibility of Mmp-19-deficient (Mmp-19(-/-)) mice to colitis. Absence of MMP-19 leads to significant disease progression, with reduced survival rates, severe tissue destruction, and elevated levels of pro-inflammatory modulators in the colon and plasma, and failure to resolve inflammation. There was a striking delay in neutrophil infiltration into the colon of Mmp-19(-/-) mice during the acute colitis, leading to persistent inflammation and poor recovery; this was rescued by reconstitution of irradiated Mmp-19(-/-) mice with wild-type bone marrow. Additionally, Mmp-19-deficient macrophages exhibited decreased migration in vivo and in vitro and the mucosal barrier appeared compromised. Finally, chemokine fractalkine (CX3CL1) was identified as a novel substrate of MMP-19, suggesting a link between insufficient processing of CX3CL1 and cell recruitment in the Mmp-19(-/-) mice. MMP-19 proves to be a critical factor in balanced host response to colonic pathogens, and for orchestrating appropriate innate immune response in colitis.

• MeSH
• Chemokine CX3CL1 metabolism   MeSH
• Cytokines metabolism   MeSH
• Inflammatory Bowel Diseases immunology   MeSH
• Neutrophil Infiltration genetics   MeSH
• Colitis chemically induced   immunology   MeSH
• Colon immunology   MeSH
• Cells, Cultured MeSH
• Humans MeSH
• Macrophages immunology   MeSH
• Inflammation Mediators metabolism   MeSH
• Matrix Metalloproteinases, Secreted genetics   metabolism   MeSH
• Mice, Inbred C57BL MeSH
• Mice, Knockout MeSH
• Mice MeSH
• Cell Movement MeSH
• Immunity, Innate MeSH
• Disease Progression MeSH
• Dextran Sulfate MeSH
• Intestinal Mucosa immunology   pathology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Chemokine CX3CL1 MeSH
• Cx3cl1 protein, mouse MeSH Browser
• Cytokines MeSH
• matrix metalloproteinase 19 MeSH Browser
• Inflammation Mediators MeSH
• Matrix Metalloproteinases, Secreted MeSH
• Dextran Sulfate MeSH

BACKGROUND: Ursodeoxycholic acid (UDCA) is used to treat primary biliary cirrhosis, intrahepatic cholestasis, and other cholestatic conditions. Although much has been learned about the molecular basis of the disease pathophysiology, our understanding of the effects of UDCA remains unclear. Possibly underlying its cytoprotective, anti-apoptotic, anti-oxidative effects, UDCA was reported to regulate the expression of TNFα and other inflammatory cytokines. However, it is not known if this effect involves also modulation of ADAM family of metalloproteinases, which are responsible for release of ectodomains of inflammatory cytokines from the cell surface. We hypothesized that UDCA modulates ADAM17 activity, resulting in amelioration of cholestasis in a murine model of bile duct ligation (BDL). METHODS: The effect of UDCA on ADAM17 activity was studied using the human liver hepatocellular carcinoma cell line HepG2. Untransfected cells or cells ectopically expressing human ADAM17 were cultured with or without UDCA and further activated using phorbol-12-myristate-13-acetate (PMA). The expression and release of ADAM17 substrates, TNFα, TGFα, and c-Met receptor (or its soluble form, sMet) were evaluated using ELISA and quantitative real-time (qRT) PCR. Immunoblotting analyses were conducted to evaluate expression and activation of ADAM17 as well as the level of ERK1/2 phosphorylation after UDCA treatment. The regulation of tissue inhibitor of metalloproteinases-1 (TIMP-1) by UDCA was studied using zymography and qRT-PCR. A mouse model of acute cholestasis was induced by common BDL technique, during which mice received daily orogastric gavage with either UDCA or vehicle only. Liver injury was quantified using alkaline phosphatase (ALP), relative liver weight, and confirmed by histological analysis. ADAM17 substrates in sera were assessed using a bead multiplex assay. RESULTS: UDCA decreases amount of shed TNFα, TGFα, and sMet in cell culture media and the phosphorylation of ERK1/2. These effects are mediated by the reduction of ADAM17 activity in PMA stimulated cells although the expression ADAM17 is not affected. UDCA reduced the level of the mature form of ADAM17. Moreover, UDCA regulates the expression of TIMP-1 and gelatinases activity in PMA stimulated cells. A BDL-induced acute cholangitis model was characterized by increased relative liver weight, serum levels of ALP, sMet, and loss of intracellular glycogen. UDCA administration significantly decreased ALP and sMet levels, and reduced relative liver weight. Furthermore, hepatocytes of UDCA-treated animals retained their metabolic activity as evidenced by the amount of glycogen storage. CONCLUSIONS: The beneficial effect of UDCA appears to be mediated in part by the inhibition of ADAM17 activation and, thus, the release of TNFα, a strong pro-inflammatory factor. The release of other ADAM17 substrates, TGFα and sMet, are also regulated this way, pointing to a general impact on the release of ADAM17 substrates, which are pivotal for liver regeneration and function. In parallel, UDCA upregulates TIMP-1 that in turn inhibits matrix metalloproteinases, which destroy the hepatic ECM in diseased liver. This control of extracellular matrix turnover represents an additional beneficial path of UDCA treatment.

• MeSH
• Hep G2 Cells MeSH
• Cholagogues and Choleretics pharmacology   MeSH
• Cholestasis MeSH
• Hepatocytes drug effects   MeSH
• Liver drug effects   MeSH
• Ursodeoxycholic Acid pharmacology   MeSH
• Humans MeSH
• Ligation MeSH
• MAP Kinase Signaling System drug effects   MeSH
• Mice MeSH
• ADAM17 Protein MeSH
• ADAM Proteins drug effects   MeSH
• Proto-Oncogene Proteins c-met drug effects   metabolism   MeSH
• Tumor Necrosis Factor-alpha drug effects   metabolism   MeSH
• Transforming Growth Factor alpha drug effects   metabolism   MeSH
• Bile Ducts surgery   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• ADAM17 protein, human MeSH Browser
• Adam17 protein, mouse MeSH Browser
• Cholagogues and Choleretics MeSH
• Ursodeoxycholic Acid MeSH
• ADAM17 Protein MeSH
• ADAM Proteins MeSH
• Proto-Oncogene Proteins c-met MeSH
• Tumor Necrosis Factor-alpha MeSH
• Transforming Growth Factor alpha MeSH