[Mechanism of microRNA-29a regulating steatosis in the human hepatocyte via targeting silent mating type information regulation 2 homolog-1].

Objective To investigate the expression of microRNA-29 a(miR-29 a) in the human steatotic hepatocyte model and the mechanism of targeting silent mating type information regulation 2 homolog-1(Sirt1)to regulate fat deposition of steatotic hepatocyte. Methods The nonalcoholic fatty liver cell model was induced by a mixture of oleic acid and palmitic acid. After successful validation model, the expression of miR-29 a and Sirt1 was measured by PCR. The target genes of miR-29 a was predicted in biological system. MiR-29 a mimic and miR-29 a inhibitor were transfected into hepatocytes, and then established the human steatotic hepatocyte model, the result of oil red O staining and triglyceride(TG)lipid content were observed, the expression of Sirt1 mRNA and protein were detected by qRT-PCR and Western blotting, respectively. Results The steatosis hepatocyte model was successfully established. Compared with control group, the relative expression of miR-29 a and triglyceride increased significantly(Pl0. 01), while the relative expression of Sirt1 decreased significantly(Pl0. 01) in the model group. Sirt1 was a target gene of miR-29 a. After transfection, the lipid droplet and the deposition of fat increased obviously in miR-29 a mimic group than those in the control group. TG content in miR-29 a mimic group increased significantly(Pl0. 05), the expression of miR-29 a increased significantly(Pl0. 01), while the expression of Sirt1 mRNA decreased significantly(Pl0. 05), and the expression of Sirt1 protein showed a downtrend. On the contrary, after the inhibition of miR-29 a expression, the lipid droplets in miR-29 a inhibitor group were relatively reduced, the fat deposition was alleviated. The TG content was significantly decreased(Pl0. 05), the expression of miR-29 a in the cells was effectively inhibited(Pl0. 01), while the expression of Sirt1 mRNA was significantly increased(Pl0. 05), and Sirt1 protein was on an upward compared with the control group. Conclusion The expression of miR-29 a is significantly increased in the nonalcoholic fatty liver cell model. Upregulation of miR-29 a negatively regulates the expression of Sirt1, thus promoting fat deposition of steatotic hepatocyte.