Leptin-induced autophagy regulates the immunomodulatory potential of adipose-derived mesenchymal stem cells through down regulating the expression of TSG-6

Abstract

Abstract Adipose-derived mesenchymal stem cells (ADMSCs) possess modulatory functions in adipose tissue, which could help combat the development of obesity. It has been reported that the functions of ADMSCs are impaired by obese microenvironment. However, the mechanisms are not clearly understood. The study investigates the role of leptin on immunoinhibitory functions of ADMSCs in obesity, and primarily explored its possible mechanisms. ADMSCs were isolated and identified by morphological observation, flow cytometry and differentiation potential. The lipopolysaccharides (LPS)-stimulated macrophages were co-cultured with ADMSCs pretreated with or without leptin. The expression of macrophage-associated markers was detected by flow cytometry. The secretion of inflammatory cytokines was evaluated by ELISA. Autophagy and MAPK signaling related proteins were detected by western blotting. Furthermore, the expression of tumor necrosis factor-alpha-stimulated protein 6 (TSG-6) was detected by western blotting, qRT-PCR, and ELISA. ADMSCs belonged to CD73 + CD90 + CD105 + / CD14 - CD34 - CD45 - HLA-DR - cells, and capable differentiation to adipogenic, osteogenic and chondrogenic cells. The immunosuppressive effect of ADMSCs on macrophage activation were restrained by leptin mediated the expression of TSG-6. Inhibition of leptin induced autophagy by Atg5 knockdown increased the expression of TSG-6, and promoted ADMSCs immunosuppression for macrophage activation. Furthermore, leptin induced autophagy and decreased the expression of TSG-6 in ADMSCs was dependent on the activation of p38 MAPK pathway. In conclusion, our study confirmed that leptin-induced autophagy regulated the immunomodulatory potential of ADMSCs through downregulating the expression of TSG-6 via the activation of p38 pathway. These findings reveal a novel mechanism and provide a potential molecular target for understanding the immunomodulatory dysfunction of ADMSCs in obesity.