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2022, Vol. 26 ›› Issue (5): 756-761miR-373 inhibits hepatic stellate cell activation by downregulating transforming growth factor beta type II receptorXu Jing1, Yan Yongmin2, Cai Mengjie2, 3
Abstract: BACKGROUND: Activated hepatic stellate cells can secrete a large amount of collagen, which is the main factor in the progression of liver fibrosis. miRNA plays an important role in the activation and apoptosis of hepatic stellate cells. The role and mechanism of miR-373 in regulating collagen secretion from hepatic stellate cell are still unclear. OBJECTIVE: To investigate the role of miR-373 in the regulation of transforming growth factor beta type II receptor (TGFβR2) in collagen secretion from hepatic stellate cells. METHODS: Bal b/c mouse model of liver fibrosis was established by CCl4 injection. Masson staining was used to detect the collagen content of liver tissues. Serum samples from liver fibrosis mice were collected and total RNA was extracted by Trizol method. Quantitative reverse transcription PCR (qRT-PCR) was used to analyze the expression level of mouse mmu-miR-291a-3p (the homologous sequence of human hsa-miR-373-3p). The expression of TGFβR2 and α-smooth muscle actin in liver tissue was detected by immunohistochemistry. TargetScan software was used to predict the target gene of miR-373. The dual luciferase reporter gene assay was used to detect the activity of miR-373 regulating TGFβR2 promoter. Human hepatic stellate cells (LX-2) were transfected with miR-373 mimics (25 and 50 nmol/L) to overexpress miR-373. LX-2 cells transfected with random miRNA sequence served as a control. Western blot and immunofluorescence were used to investigate the effect of miR-373 on the expression of TGFβR2 and fibroblast activation protein. The study protocol was approved by the Experimental Animal Ethics Committee of Jiangsu University (approval No. UJS-IACUC-AP-2020033127). RESULTS AND CONCLUSION: Serum mmu-miR-291a-3plevel was significantly decreased in the fibrosis group compared with the health control group (P < 0.001), and collagen synthesis in the liver was significantly increased. Co-expression of TGFβR2 and α-smooth muscle actin in liver fibrosis tissue was obviously increased compared with the control group. miR-373 significantly inhibited the activity of TGFβR2 promoter in LX-2 cells (P < 0.01). The expression of TGFβR2 and fibroblast activation protein in LX-2 cells was significantly downregulated by miR-373 overexpression (P < 0.01). To conclude, miR-373 can inhibit the activation of hepatic stellate cells and collagen deposition in liver tissues by downregulating the expression of TGFβR2. Key words:liver fibrosis, miRNA, miR-373, transforming growth factor beta type II receptor, TGFβR2 |