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

Abstract

Backgrund 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 (PKCε) 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 PKCε 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 PKCε 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 PKCε-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 PKCε-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 PKCε significantly reduced resistin-mediated cytosolic ROS, Nox activity and VSMC dysfunction. Moreover, PKCε-specific inhibitor mitigated resistin-induced Nox activation and intimal hyperplasia in ApoE−/− mice. Conclusions Resistin-associated VSMC dysfunction and intimal hyperplasia are related to PKCε-dependent Nox activation and ROS generation. Targeting the PKCε-Nox pathway may represent a novel strategy in managing resistin-associated atherosclerotic complications.

PKC-epsilon and TLR4 synergistically regulate resistin-mediated inflammation in human macrophages

“…16, 24 In this study, we observed that PKCε is a key mediator of resistin signaling for macrophage activation, suggesting that inhibiting PKCε has anti-inflammatory properties. Our study is in line with previous findings proposing that TLR4 participates in resistin-associated activity in macrophages.…”

“…We recently showed that resistin increased ROS production, NADPH oxidase (Nox) activity, and inflammatory cytokine secretion in VSMCs. 16 We speculate that ROS production and Nox activity may also contribute to this pathway, and play important roles in the overall inflammatory cascades that are activated by resistin.…”

“…12, 13 We and others have demonstrated that resistin promotes vascular smooth muscle cell migration, proliferation, and dedifferentiation, and we reported that protein kinase C epsilon (PKCε) mediates such processes. 14–16 Resistin can also induce IL-6 and TNF-α productions in peripheral blood mononuclear cells (PBMCs) 17 and promote inflammation in macrophages. 18 Tarkowski et al have proposed that toll like receptor 4 (TLR4) may serve as a binding protein for resistin.…”

Hyperhomocysteinaemia and vascular injury: advances in mechanisms and drug targets

“…Resistin, an adipokine produced by perivascular adipose tissue, contributes to intimal hyperplasia and atherosclerosis (Nosalski and Guzik, ). Resistin induces the proliferation and migration of VSMCs via the ERK1/2 or PI3K‐Akt (Calabro et al ., ) and integrin α5β1‐FAK/paxillin‐Rac1 (Jiang et al ., ) or PKC (Raghuraman et al ., ) signalling pathways respectively. Moreover, resistin leads to endothelial dysfunction as shown by the up‐regulation of VCAM‐1 and ICAM‐1 expression, as well as the increased secretion of endothelin‐1 and CCL2 by ECs (Verma et al ., ; Jamaluddin et al ., ).…”

Engineering Cardiovascular Implant Surfaces to Create a Vascular Endothelial Growth Microenvironment

“…[29] The current view is inclined that SMCs migrated from the middle membrane of blood vessel walls participates in the early stage of IH. [30][31][32] Another view is that the physiological phenotype of SMCs is contractile, while the pathological phenotype of SMCs is synthetic, and the change of SMCs from contractile to synthetic phenotype leads to IH happen. [33] Recent finding showed that multipotent vascular stem cells also contribute to intimal hyperplasia by differentiating into synthetic SMCs, [34] which further challenged the general dogma about de-differentiation of SMCs from the contractile to the synthetic phenotype.…”