Abstract: Objective To study the molecular mechanism of microRNA-194 (miR-194) alleviating lipid metabolism and inflammation in lipotoxic hepatocytes.Methods Low-fat diet (LFD) and high-fat diet (high-fat diet, HFD) were applied to construct a control group and a fatty liver mouse model. HE staining and oil red staining were used to observe the modeling. The expression levels of miR-194, lipid synthesis factors SCD1, ACC, proinflammatory factors TNF-α and IL-6 in the two groups of mice liver tissues were detected by qPCR. Palmitic acid (PA) was used to stimulate the hepatocyte cell line LO2. After miR-194 overexpression in LO2, qPCR was used to detect the expression levels of SCD1, ACC, TNF-α, IL-6 in LO2. Oil red staining was used to detect the lipid deposition in LO2, and immunofluorescence was performed to analyze the changes of TNF-α in LO2. Results HE and oil red staining showed that the fatty liver mouse model was successfully constructed. Compared with the mice in the LFD group, the expression of miR-194 in the HFD group was significantly reduced(LFD: 1.000±0.147 vs HFD: 0.634±0.116, t=3.478, P=0.025). The expression of SCD1 and ACC1 were significantly increased(SCD1 LFD: 1.000±0.287 vs HFD: 1.658±0.216, t=4.802, P=0.009; ACC LFD: 1.000±0.252 vs HFD: 1.851±0.245, t=4.194, P=0.015), and the expression of TNF-α and IL-6 were also greatly promoted(TNF-α LFD: 1.000±0.172 vs HFD: 1.952±0.147, t=7.288, P=0.002; IL-6 LFD: 1.000±0.207 vs HFD: 1.452±0.108, t=3.242, P=0.029). In the high-fat environment, after overexpression of miR-194, qPCR results showed that the expression of SCD1 and ACC in LO2 decreased significantly (SCD1 miR-NC: 1.000±0.149 vs miR-194: 0.625±0.112, t=3.340, P=0.029; ACC miR-NC: 1.000±0.204 vs miR-194:0.572±0.124, t=3.105, P=0.038), and the expression of TNF-α and IL-6 decreased significantly (TNF-α miR-NC: 1.000±0.149 vs miR-194: 0.563±0.059, t=4.723, P=0.009; IL-6 miR-NC: 1.000±0.156 vs miR-194: 0.685±0.112, t=2.853, P=0.048). Oil red staining showed that the lipid deposition in LO2 was significantly alleviated, and the immunofluorescence results showed that the expression of TNF-α in the cells was markedly decreased (miR-NC: 1.000±0.124 vs miR-194: 0.655±0.152, t=3.020, P=0.039). Conclusion MiR-194 could decrease the lipid deposition and inflammatory response induced by high-fat diet, and alleviate the progression of fatty liver. This may become a new target for the treatment of nonalcoholic fatty liver disease.

Key words: MicroRNA-194, Lipid deposition, Inflammation, Nonalcoholic fatty liver disease