Metformin alleviates intestinal epithelial barrier damage by inhibiting endoplasmic reticulum stress-induced cell apoptosis in colitis cell model

Abstract

To investigate the effect and mechanism of metformin on intestinal epithelial barrier injury in ulcerative colitis. A cell model of colitis was established by co-culture of human colon cancer cell line Caco-2 and human monocyte cell line THP-1. The colitis model cells were treated with metformin at concentration of for Flow cytometry was used to detect Caco-2 cell apoptosis, and Western blotting was used to detect the protein expression of tight junction proteins and endoplasmic reticulum stress-related proteins. After metformin treatment, the apoptosis rate of Caco-2 cells was decreased from (14.22±2.34)% to 0.61)% (=3.119, <0.05), and the expression levels of tight junction protein-1 and claudin-1 increased (=5.172 and 3.546, both <0.05). In addition, the expression levels of endoplasmic reticulum-related proteins glucose regulated protein (GRP) 78, C/EBP homologous protein (CHOP) and caspase-12, as well as the phosphorylation level of PRKR-like endoplasmic reticulum kinase (PERK) and eukaryotic translation initiation factor 2α (eIF2α) decreased (all <0.05). Metformin may alleviate the intestinal epithelial barrier damage in colitis by reducing intestinal epithelial cell apoptosis and increasing the expression of tight junction proteins, which may be associated with the inhibition of endoplasmic reticulum stress-induced apoptotic pathway.

Keywords: Apoptosis; Co-culture cell; Colitis, ulcerative; Endoplasmic reticulum stress; Metformin; Tight junction protein.

图 1

模型对照组和二甲双胍组结肠炎肠上皮细胞凋亡流式细胞图

图 2

模型对照组和二甲双胍组紧密连接蛋白1和密封蛋白1表达电泳图

图 3

模型对照组和二甲双胍组内质网应激相关蛋白表达电泳图GRP：葡萄糖调节蛋白；PERK：蛋白激酶R样内质网激酶；eIF2α：真核生物起始因子2α；CHOP：C/EBP同源蛋白；caspase：胱天蛋白酶.