ATP6V1B2通过促进溶酶体酸化抑制脂毒损伤肝细胞脂质沉积OA

Objective:To investigate the role and mechanism of ATP6V1B2 in the inhibiton of lipid deposition by promotinglysosomal acidification in lipotoxin-exposed hepatocytes.Methods:Hepatic steatosis model mice were constructed by feeding male C57BL/6 mice with a high-fat diet for 14 weeks.Lipotoxic injury was induced in hepatocyte lines L02 and HepG2 using a mixture of oleic acid and palmitic acid.The expression of ATP6V1B2 gene in L02 cells was knocked down or overexpressed by siRNA and plasmid transfection.The mRNA and protein expressions of ATP6V1B2 were detected by qRT-PCR and Western blotting,respectively.Hepatocyte lipid deposition was detected by oil red O staining and Nile red staining.Lysosomal activity was detected by lyso-tracker in lipotoxic hepatocytes.Lysosomal membrane integrity was detected by acridine orange staining.The JASPAR database was used to predict transcription factors regulating ATP6V1B2,and the regulatory effect of transcription factors on ATP6V1B2 expression was verified.Results:Compared with the normal control group,ATP6V1B2 expression was decreased in hepatic tissues of high-fat diet mice and lipotoxic hepatocytes(P＜0.05).ATP6V1B2 knockdown exacerbated hepatocyte lipid deposition,inhibited hepatocyte lysosomal acidification,and increased hepatocyte lysosomal membrane permeability.Overexpression of ATP6V1B2 alleviated cellular lipid deposition.Transcription factor SP1 could transcriptionally regulate ATP6V1B2 expression.Compared with the control group,silencing SP1 upregulates the mRNA and protein expression of ATP6V1B2 in L02 cells(P＜0.01).Conclusion:ATP6V1B2 may inhibit hepatocyte lipid deposition by promoting hepatocyte lysosomal acidification.