PKCε mediates resistin-induced NADPH oxidase activation and inflammation leading to smooth muscle cell dysfunction and intimal hyperplasia

Background and aims: Resistin has been implicated in cardiovascular disease and poor interventional cardiovascular outcomes. Previous studies by our group demonstrated resistin promoted vascular smooth muscle cell (VSMC) migration through protein kinase C epsilon (PKC epsilon) pathways, while few others showed that resistin induced reactive oxygen species (ROS) generation in various cell types. In this study, we aim to systemically examine the functional role of resistin at the cellular and tissue levels as well as the potential mechanistic relationship between resistin-induced PKCe activation and ROS production. Methods: Plasma collected from patients undergoing carotid interventions was analyzed for resistin level and ROS. VSMCs were treated with resistin in the presence or absence of PKCe and NADPH oxidase (Nox)specific inhibitors. Intracellular ROS production was analyzed using confocal microscopy and Nox activity with chemiluminescence. In vivo studies were performed in apolipoprotein E knock out (ApoE (-/-)) mice to determine therapeutic effects of PKC epsilon-specific inhibitor, using the guide-wire injury model. Results: We observed significant correlation between plasma resistin and circulating levels of oxidative stress in patients with severe atherosclerotic disease. We also demonstrated that resistin induced ROS production via PKC epsilon-mediated Nox activation. Resistin-induced ROS production was time-dependent, and Nox4 was the primary isoform involved. Inhibition of Nox completely abolished resistin-exaggerated VSMC proliferation, migration and dedifferentiation, as well as pro-inflammatory cytokine release. Upstream modulation of PKCe significantly reduced resistin-mediated cytosolic ROS, Nox activity and VSMC dysfunction. Moreover, PKCe-specific inhibitor mitigated resistin-induced Nox activation and intimal hyperplasia in ApoE (-/-) mice. Conclusions: Resistin-associated VSMC dysfunction and intimal hyperplasia are related to PKC epsilon-dependent Nox activation and ROS generation. Targeting the PKC epsilon-Nox pathway may represent a novel strategy in managing resistin-associated atherosclerotic complications. Published by Elsevier Ireland Ltd.