Mechanisms of the influence of adiponectin on apolipoproteins A-1 and B production by human hepatocytes

The aim of the study was to find out the mechanisms of the adiponectin effect on apolipoproteins (apo) A-1 and B production by human hepatocytes. Materials and methods. The study was performed on the human hepatoma cell line HepG2. The expression of the apoA-1 gene was evaluated at the mRNA level by quantitative PCR with reverse transcription, and the production of apo B by ELISA method. The activity of lipogenesis was assessed by the inclusion of labeled 14C-acetate in triglycerides, as well as by mRNA expression of lipogenesis genes, and by the estimation of total triglycerides content in cells. To determine the involvement of signaling pathways, the RNA interference method was used. Results. Knockdown of genes, coding the specific receptors, AMP-activated protein kinase, and its regulated transcription factors inhibited adiponectin-dependent stimulation of apoA-1 gene expression in hepatocytes. Adiponectin had no effect on lipogenesis and apo B production under basal conditions, but suppressed these processes induced by the addition of oleate. Conclusion. Adiponectin stimulates the production of apo A-1 in hepatocytes by inducing the transcription of the apoA-1 gene and suppresses the secretion of apo B by affecting lipogenesis. These effects may underlie the effect of adiponectin on lipoproteins metabolism.