Matrix metalloproteinases modulated by protein kinase Cε mediate resistin-induced migration of human coronary artery smooth muscle cells

Abstract

BackgroundEmerging evidence showed that resistin induces vascular smooth muscle cell (VSMC) migration, a critical step in initiating vascular restenosis. Adhesion molecule expression and cytoskeletal rearrangement have been observed in this progress. Given that matrix metalloproteinases (MMPs) also regulate cell migration, we hypothesized that MMPs may mediate resistin-induced VSMC migration.MethodsHuman VSMCs were treated with recombinant human resistin at physiologic (10 ng/mL) and pathologic (40 ng/mL) concentrations for 24 hours. Cell migration was determined by the Boyden chamber assay. MMP and tissue inhibitor metalloproteinase (TIMP) mRNA and protein levels were measured with real-time PCR and ELISA. MMP enzymatic activity was measured by zymography. In another experiment, neutralizing antibodies against MMP-2 and MMP-9 were coincubated with resistin in cultured VSMCs. The regulation of MMP by protein kinase C (PKC) was determined by εV1-2, a selective PKCε inhibitor.ResultsResistin-induced smooth muscle cell (SMC) migration was confirmed by the Boyden chamber assay. Forty nanograms/milliliter resistin increased SMC migration by 3.7 fold. Additionally, resistin stimulated MMP-2 and -MMP9 mRNA and protein expressions. In contrast, the TIMP-1 and TIMP-2 mRNA levels were inhibited by resistin. Neutralizing antibodies against MMP-2 and MMP-9 effectively reversed VSMC migration. Furthermore, resistin activated PKCε, but selective PKCε inhibitor suppressed resistin-induced MMP expression, activity, and cell migration.ConclusionsOur study confirmed that resistin increased vascular smooth muscle cell migration in vitro. In terms of mechanism, resistin-stimulated cell migration was associated with increased MMP expression, which was dependent on PKCε activation.Clinical RelevanceResistin, secreted by adipocytes and elevated in obese patients with type II diabetes, has shown to promote vascular smooth muscle cell (VSMC) migration, a key step in vascular restenosis following arterial interventions. In this study, we confirmed the migratory effect of resistin on human vascular smooth muscle cells and investigated the mechanisms underlying this phenotypic observation: matrix metalloproteinases modulated by protein kinase C (PKC)ε may mediate resistin-induced VSMC migration. Based on those mechanistic data, selective PKCε inhibitor may be a potential therapeutic strategy for treating restenosis in the group of high-risk patients with type II diabetes