Effects of ROS-relative NF-κB signaling on high glucose-induced TLR4 and MCP-1 expression in podocyte injury

High glucose (HG) induced inflammation is central to progression in diabetic nephropathy (DN). Recent studies have suggested that nuclear factor-kappa B (NF-kappa B) signaling activation is associated with ON, and podocyte damage may be involved in orchestrating these effects. Therefore, the aim of this study was to investigate the effects of NF-kappa B signaling on podocytes under HG conditions. The effects of HG and NF-kappa B signaling on podocytes were assessed by CCK-8 assay, cellular NF-kappa B translocation assay, measurement of reactive oxygen species (ROS) and Western blot analysis. We found that HG reduced cell viability, activated NF-kappa B signaling and up-regulated toll-like receptor 4 (TLR4) and monocyte chemoattractant protein-1 (MCP-1). In these cells, NF-kappa B inhibition with ammonium pyrrolidinethiocarbamate (PDTC) resulted in effectively constraining TLR4 and MCP-1 up-regulation, indicating that protective effects associated with the inhibition of NF-kappa B were linked to TLR4 and MCP-1 down-regulation in podocytes. Furthermore, HG significantly increased the production of intracellular ROS. Pretreatment with N-acetyl-L-cysteine (NAC) significantly inhibited intracellular ROS generation and increased cell viability, accompanied by a significant NF-kappa B inhibition and suppression of TLR4 and inflammatory cytokine MCP-1 expression. Collectively, our novel data suggest that HG induces the over-experssion of TLR-4 and MCP-1 through a NF-kappa B-dependent signaling. NF-kappa B-mediated increased inflammation is possibly via ROS and contributes to the cell injury. These results may provide potential therapeutic target for diabetic nephropathy in the future. (C) 2015 Elsevier Ltd. All rights reserved.