PPARγ Enhanced The Adiponectin HMw Secretion Via Upregulating Dsb-L

Disulfide-bond A oxidoreductase like-protein (DsbA-L) was identified as a molecular chaperone facilitating the assembly and secretion of adiponectin, an adipokine with multiple salutary effects. It has been documented in obesity; the level of DsbA-L is reduced with a concomitant decrease in circulating adiponectin level, especially the high molecular weight form (HMW). Both rodent and human studies have shown that the nuclear receptor peroxisome proliferator-activated receptor (PPAR)y agonists increase circulating adiponectin levels in serum by activating PPARy, which up-regulates critical endoplasmic reticulum (ER) chaperones to make a more productive protein folding environment. In addition, DsbA-L is a newly identified member of disulfide isomerase (PDI) family, but its precise role in stimulating the assembly and secretion of adiponectin remains to be elucidated.In this study, dual luciferase reporter system, cell transfection, gene knockdown quantitative real-time PCR(QRT-PCR), Chromosome Immunoprecipitation (ChIP), WB(WB), and other molecular biological techniques were utilized to analysis the facilitation of PPARy on extracellular adiponectin high molecular weight secretion and the effect of PPARγ on DsbA-L, thereby elucidating the important role of DsbA-L played in PPARy-mediating adiponectin secretion. The results as follows:1.PPARy enhanced the extracellular adiponectin HMW, which was determined by WB after gene transfection. Then QRT-PCR and WB were used to detect the increase level of adiponectin and its assembly and secretion related proteins.2.The putative PPRE sites in DsbA-L promoter were present by Bioinformatic analysis. And PPARy increasing the DsbA-L expression via binding directly to DsbA-L promoter was proved by gene transfection, dual luciferase reporter system, promoter mutant, promoter truncation and ChIP.3.Gene knockdown and WB were applied to analyze the extracellular adiponectin HMW in differentiated adipocytes transefected with shPPARγ/shDsbA-L. By using gene transfection and WB, DsbA-L overexpression facilitating the extracellular adiponectin HMW was verified in HEK293.