DUSP6 protects murine podocytes from high glucose-induced inflammation and apoptosis

Diabetic nephropathy (DN) is one of the most severe complications that can occur in patients with diabetes, and without effective and timely therapeutic intervention, can gradually progress to renal failure. Previous studies have focused on investigating the pathogenesis of DN; however, the role of dual-specificity phosphatase 6 (DUSP6) in DN is not completely understood. Therefore, the present study aimed to investigate the role of dual-specificity phosphatase 6 (DUSP6) in DN. DN model mice were established and the expression levels of DUSP6 in the kidney tissues and high glucose (HG)-induced murine podocytes (MPC5 cells) were determined using immunohistochemistry, reverse transcription-quantitative PCR and western blotting. In addition, the levels of reactive oxygen species (ROS) and inflammatory cytokines in MPC5 cells were analyzed using commercial assay kits or ELISA kits, respectively, and flow cytometric analysis was performed to analyze the rate of cell apoptosis. The present study indicated that DUSP6 expression levels were significantly decreased in DN model mice compared with control mice, and in HG-induced MPC5 cells compared with normal glucose-induced MPC5 cells. DUSP6 overexpression enhanced MPC5 cell viability and increased protein expression levels of cell markers, such as synaptopodin and nephrin, compared with the negative control group. DUSP6 overexpression also reduced the levels of ROS and inflammatory cytokines, including interleukin (IL)-1β, IL-6 and tumor necrosis factor-α secreted by MPC5 cells under HG conditions. Moreover, compared with the HG group, cell apoptosis was inhibited by DUSP6 overexpression under HG conditions, which was further indicated by decreased expression levels of cleaved caspase-3 and Bax. Thus, these findings indicated that DUSP6 mediated the protection against HG-induced inflammatory response.