SOCS3 inhibits insulin signaling in porcine primary adipocytes

Insulin resistance is a major player in the pathogenesis of type II diabetes, the metabolic syndrome, and obesity. SOCS3 plays an important role in the development of insulin resistance. To investigate the role of SOCS3 in porcine adipocyte insulin signaling, we first detected the effect of insulin on SOCS3 mRNA and protein expression in porcine primary adipocytes by real-time RT-PCR and Western blotting. Then, we constructed a recombinant adenovirus encoding SOCS3 gene (Ad-SOCS3) which was used to infect differentiated porcine primary adipocytes for 3 days. The expression and phosphorylation of main insulin signaling components were detected by Western blotting. The results showed that 100 nM insulin could induce SOCS3 mRNA expression but not protein expression, and overexpression of SOCS3 decreased IRS1 protein level, insulin-stimulated IRS1 tyrosine phosphorylation, PI3K activation, and Akt phosphorylation, but increased IRS1 serine phosphorylation in porcine primary adipocytes. These results indicate that SOCS3 is an important negative regulator of insulin signaling in porcine adipocytes. Thus, SOCS3 may be a novel therapeutic target for the prevention or treatment of insulin resistance and type II diabetes.