BACKGROUND & AIMS: Plectin, a highly versatile cytolinker protein, controls intermediate filament cytoarchitecture and cellular stress response. In the present study, we investigate the role of plectin in the liver under basal conditions and in experimental cholestasis. METHODS: We generated liver-specific plectin knockout (PleΔalb) mice and analyzed them using two cholestatic liver injury models: bile duct ligation (BDL) and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) feeding. Primary hepatocytes and a cholangiocyte cell line were used to address the impact of plectin on keratin filament organization and stability in vitro. RESULTS: Plectin deficiency in hepatocytes and biliary epithelial cells led to aberrant keratin filament network organization, biliary tree malformations, and collapse of bile ducts and ductules. Further, plectin ablation significantly aggravated biliary damage upon cholestatic challenge. Coincidently, we observed a significant expansion of A6-positive progenitor cells in PleΔalb livers. After BDL, plectin-deficient bile ducts were prominently dilated with more frequent ruptures corresponding to an increased number of bile infarcts. In addition, more abundant keratin aggregates indicated less stable keratin filaments in PleΔalb hepatocytes. A transmission electron microscopy analysis revealed a compromised tight junction formation in plectin-deficient biliary epithelial cells. In addition, protein profiling showed increased expression of the adherens junction protein E-Cadherin, and inefficient upregulation of the desmosomal protein desmoplakin in response to BDL. In vitro analyses revealed a higher susceptibility of plectin-deficient keratin networks to stress-induced collapse, paralleled by elevated activation of p38 MAP kinase. CONCLUSION: Our study shows that by maintaining proper keratin network cytoarchitecture and biliary epithelial stability, plectin plays a critical role in protecting the liver from stress elicited by cholestasis. LAY SUMMARY: Plectin is a cytolinker protein capable of interconnecting all three cytoskeletal filament systems and linking them to plasma membrane-bound junctional complexes. In liver, the plectin-controlled cytoskeleton mechanically stabilizes epithelial cells and provides them with the capacity to adapt to increased bile pressure under cholestasis.

• MeSH
• cholestáza metabolismus   patologie   MeSH
• epitel metabolismus   patologie   MeSH
• hepatocyty metabolismus   patologie   MeSH
• játra abnormality   metabolismus   patologie   MeSH
• keratiny metabolismus   MeSH
• MAP kinasový signální systém MeSH
• mitogenem aktivované proteinkinasy p38 metabolismus   MeSH
• myši knockoutované MeSH
• myši MeSH
• plektin nedostatek   genetika   metabolismus   MeSH
• stabilita proteinů MeSH
• žlučové ústrojí abnormality   metabolismus   patologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Liver fibrosis is characterized by the deposition and increased turnover of extracellular matrix. This process is controlled by matrix metalloproteinases (MMPs), whose expression and activity dynamically change during injury progression. MMP-19, one of the most widely expressed MMPs, is highly expressed in liver; however, its contribution to liver pathology is unknown. The aim of this study was to elucidate the role of MMP-19 during the development and resolution of fibrosis by comparing the response of MMP-19-deficient (MMP19KO) and wild-type mice upon chronic liver CCl(4)-intoxication. We show that loss of MMP-19 was beneficial during liver injury, as plasma ALT and AST levels, deposition of fibrillar collagen, and phosphorylation of SMAD3, a TGF-ß1 signaling molecule, were all significantly lower in MMP19KO mice. The ameliorated course of the disease in MMP19KO mice likely results from a slower rate of basement membrane destruction and ECM remodeling as the knockout mice maintained significantly higher levels of type IV collagen and lower expression and activation of MMP-2 after 4 weeks of CCl(4)-intoxication. Hastened liver regeneration in MMP19KO mice was associated with slightly higher IGF-1 mRNA expression, slightly increased phosphorylation of Akt kinase, decreased TGF-ß1 mRNA levels and significantly reduced SMAD3 phosphorylation. In addition, primary hepatocytes isolated from MMP19KO mice showed impaired responsiveness towards TGF-ß1 stimulation, resulting in lower expression of Snail1 and vimentin mRNA. Thus, MMP-19-deficiency improves the development of hepatic fibrosis through the diminished replacement of physiological extracellular matrix with fibrotic deposits in the beginning of the injury, leading to subsequent changes in TGF-ß and IGF-1 signaling pathways.

• MeSH
• chronická nemoc MeSH
• hepatocyty cytologie   MeSH
• insulinu podobný růstový faktor I metabolismus   MeSH
• jaterní cirhóza chemicky indukované   enzymologie   MeSH
• metaloproteinasy secernované do matrix genetika   MeSH
• modely nemocí na zvířatech MeSH
• myši knockoutované MeSH
• myši MeSH
• otrava chloridem uhličitým enzymologie   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• progrese nemoci MeSH
• proliferace buněk MeSH
• signální transdukce MeSH
• transformující růstový faktor beta metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Blood platelet and monocyte adhesion was studied in vitro with respect to the influence of hydrophilic polymer chemical functional groups and their charge. The results showed that the strongest adhesion of human monocytes was to coverslips covered with cationic polymer. Platelet adhesion to all tested polymers proved to be negligible; no differences related to the charge of the polymers used were observed. These results show the obvious difference between the biocompatibility and haemocompatibility in vitro which must be taken into consideration during polymer biological properties testing before clinical trials.

• MeSH
• adhezivita trombocytů * MeSH
• hydrogely * MeSH
• lidé MeSH
• monocyty * MeSH
• polymery * MeSH
• techniky in vitro MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• srovnávací studie MeSH