RESUMO
Objective: To explore the pathogenic mechanism of the miR-340/high mobility group box 1 (HMGB1) axis in the formation of liver fibrosis. Methods: A rat liver fibrosis model was established by injecting CCl(4) intraperitoneally. miRNAs targeting and validating HMGB1 were selected with gene microarrays after screening the differentially expressed miRNAs in rats with normal and hepatic fibrosis. The effect of miRNA expressional changes on HMGB1 levels was detected by qPCR. Dual luciferase gene reporter assays (LUC) was used to verify the targeting relationship between miR-340 and HMGB1. The proliferative activity of the hepatic stellate cell line HSC-T6 was detected by thiazolyl blue tetrazolium bromide (MTT) assay after co-transfection of miRNA mimics and HMGB1 overexpression vector, and the expression of extracellular matrix (ECM) proteins type I collagen and α-smooth muscle actin (SMA) was detected by western blot. Statistical analysis was performed by analysis of variance and the LSD-t test. Results: Hematoxylin-eosin and Masson staining results showed that the rat model of liver fibrosis was successfully established. Gene microarray analysis and bioinformatics prediction had detected eight miRNAs possibly targeting HMGB1, and animal model validation had detected miR-340. qPCR detection results showed that miR-340 had inhibited the expression of HMGB1, and a luciferase complementation assay suggested that miR-340 had targeted HMGB1. Functional experiments results showed that HMGB1 overexpression had enhanced cell proliferation activity and the expression of type I collagen and α-SMA, while miR-340 mimics had not only inhibited cell proliferation activity and the expression of HMGB1, type I collagen, and α-SMA, but also partially reversed the promoting effect of HMGB1 on cell proliferation and ECM synthesis. Conclusion: miR-340 targets HMGB1 to inhibit the proliferation and ECM deposition in hepatic stellate cells and plays a protective role during the process of liver fibrosis.