AOPPs induce MCP-1 expression by increasing ROS-mediated activation of the NF-κB pathway in rat mesangial cells: inhibition by sesquiterpene lactones.

BACKGROUND: Monocyte chemoattractant protein-1 (MCP-1) plays an important role in extracellular matrix accumulation through macrophage recruitment and activation in the development and progression of diabetic nephropathy. Therefore, this study examined whether advanced oxidation protein products (AOPPs) are involved in nuclear factor-κB (NF-κB) activation and MCP-1 mRNA and protein expression in mesangial cells (MCs) and evaluated the effects of derivatives of sesquiterpene lactones (SLs) on AOPP-induced renal damage.
METHODS: MCP-1 mRNA and protein expression in MCs were determined by quantitative real-time PCR and ELISA, respectively. The level of intracellular reactive oxygen species (ROS) was determined by flow cytometry. The protein expression of tubulin, P47, NF-κB p65, phospho-NF-κB p65, IκB, phospho-IκB, IKKβ and phospho-IKKβ was evaluated by Western blot.
RESULTS: AOPPs caused oxidative stress in MCs and activated the NF-κB pathway by inducing IκBα phosphorylation and degradation. Inhibition of ROS by SOD (ROS inhibitor) blocked the AOPP-mediated NF-κB pathway. Moreover, the inhibition of AOPP-induced overproduction of MCP-1 mRNA and protein was associated with inhibition of IκBα degradation by SLs.
CONCLUSION: AOPPs induce MCP-1 expression by activating the ROS/NF-κB pathway and can be inhibited by SLs. These findings may provide a novel approach to treat inflammatory and immune renal diseases, including diabetic nephropathy.