Occludin endocytosis is involved in the disruption of the intestinal epithelial barrier in a mouse model of alcoholic steatohepatitis
Autor: | Xin Li, Chen Wang, Hong Yan Wang, Dong Lv, Tian Yi Wang, Cheng Chi, You Qing Xu |
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Rok vydání: | 2019 |
Předmět: |
Endocytic cycle
Occludin Endocytosis Permeability Tight Junctions 03 medical and health sciences 0302 clinical medicine medicine Animals Humans Micropinocytosis Intestinal Mucosa Barrier function Intestinal permeability Ethanol business.industry Pinocytosis Gastroenterology medicine.disease Intestinal epithelium Cell biology Mice Inbred C57BL Disease Models Animal Microscopy Electron Microscopy Fluorescence 030220 oncology & carcinogenesis 030211 gastroenterology & hepatology Caco-2 Cells business Fatty Liver Alcoholic |
Zdroj: | Journal of Digestive Diseases. 20:476-485 |
ISSN: | 1751-2980 1751-2972 |
Popis: | Objective We aimed to investigate the involvement of the endocytosis of occludin, a key component of tight junction (TJ), in the ethanol-induced disassembly of TJ in a model of alcoholic steatohepatitis. Methods Wild-type mice were fed an ethanol-containing or isocaloric liquid diet for 8 weeks and then assessed for liver injury (histopathology and measurement of serum enzymes), gut permeability (in vivo lactulose/mannitol and ex vivo dye leakage assays), intestinal epithelium ultrastructure (transmission electron microscopy), and intestinal occludin localization (immunofluorescence microscopy). The human intestinal epithelial cell line Caco-2 was also analyzed in vitro for the effects of ethanol on the barrier function (transepithelial electrical resistance), occludin localization (immunofluorescence microscopy and Western blotting), and endocytosis pathways (double-labeling immunofluorescence microscopy with selective pathway inhibitors). Results The ethanol-fed mice developed steatohepatitis and displayed intestinal barrier dysfunction, the disruption of intestinal TJ, and enhanced intestinal endocytosis of occluding compared with the control mice. In the Caco-2 monolayers, ethanol treatment decreased transepithelial electrical resistance, disrupted TJ formation, and enhanced occludin endocytosis in a dose- and time-dependent manner. These deleterious events were reversed by pretreating the Caco-2 cells with a selective pharmacological inhibitor of macropinocytosis, but not with the inhibitors of clathrin or caveolin-mediated endocytic pathways. Conclusion Chronic ethanol exposure may increase intestinal permeability by inducing the micropinocytosis of occludin, resulting in the disruption of intestinal TJ. |
Databáze: | OpenAIRE |
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