Experimental study of translocase of inner mitochondrial membrane 13 regulating the activa⁃tion and proliferation of hepatic stellate cells

Objective:To investigate the effect of translocase of inner mitochondrial membrane 13 (TIMM13)expression on the activation and proliferation of mouse hepatic stellate cells and explore the role of TIMM13 in the progression of liver fibrosis.Methods:JS-1 cells were treated with 5 ng/mL, 10 ng/mL 20 ng/mL transform-ing growth factor-β1 (TGF-β1) for 24 h to induce activation of JS-1 cells.The experiment was divided into con-trol group(0 ng/mL group), 5 ng/mL group, 10 ng/mL group and 20 ng/mL group.The mRNA and protein expres-sion levels of TIMM13, fibrosis index α-smooth muscle actin (α-SMA) and collagen I (COL1A1) in each group were detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and western blotting.TIMM13 was knocked down and overexpressed in JS-1 cells, and the experiments were divided into empty-vec-tor group (control group) and silence group/overexpression group.The mRNA and protein expression levels of TIMM13, α-SMA and COL1A1 were detected by RT-qPCR and western blotting.The cell counting kit-8 (CCK-8) assay was used to detect the proliferation of TIMM13-silenced/TIMM13-overexpressing cells at 0, 24, 48 and 72 hours.Results:Compared with the control group, the mRNA expression level of TIMM13 in the 5 ng/mL group, 10 ng/mL group and 20 ng/mL group increased (all P< 0.05), and the protein expression of TIMM13 in the 5 ng/mL group and 10 ng/mL group increased(all P< 0.05).Compared with the control group, the mRNA ex-pression levels of TIMM13, α-SMA and COL1A1 in the silencing group decreased (all P< 0.01).The protein expression levels of TIMM13 and α-SMA decreased (all P< 0.01) and the proliferation of JS-1 cells was significantly inhibited at 48 h and 72 h (all P< 0.05) while the mRNA expression levels of TIMM13, α-SMA and COL1A1 increased in the overexpression group(all P< 0.05).The protein expression levels of TIMM13 and α-SMA increased(all P< 0.05)and the prolif-eration of JS-1 cells at 48 h and 72 h was enhanced (all P< 0.05).Conclusion:The expression of TIMM13 pro-motes the activation and proliferation of hepatic stellate cells in mice, thereby facilitating the development of liv-er fibrosis.