IL-1 beta enhances vascular smooth muscle cell proliferation and migration via P2Y(2) receptor-mediated RAGE expression and HMGB1 release

Abstract

Vascular smooth muscle cells (VSMCs) are the major cell type in blood vessel walls, and their proliferation and migration play important roles in the development of atherosclerosis. Recently, it has been reported that IL-1 beta mediates the inflammatory response through the upregulation of the P2Y(2) receptor (P2Y(2)R). Thus, we examined the role of P2Y(2)R in IL-1 beta-mediated proliferation and migration of VSMCs and the underlying molecular mechanisms. VSMCs were pretreated with IL-1 beta for 24 h to upregulate P2Y(2)R expression. The cells were then stimulated with UTP or ATP for the indicated times, and cell proliferation and migration and the related signaling pathways were examined. The equipotent P2Y(2)R agonists ATP and UTP enhanced proliferation, RAGE expression and HMGB1 secretion in IL-1 beta-pretreated VSMCs. Additionally, pretreatment with IL-1 beta enhanced UTP-mediated VSMC migration and MMP-2 release, but these effects were not observed in the P2Y(2)R-siRNA- or RAGE-siRNA-transfected VSMCs. Next, the signaling molecules involved in P2Y(2)R-mediated cell proliferation and migration were determined. The ERK, AKT, PKC, Rac-1 and ROCK2 pathways were involved in UTP-induced cell proliferation and migration, MMP-2 and HMGB1 secretion and RAGE expression in the IL-1 beta-pretreated VSMCs. UTP induced the phosphorylation of ERK, AKT and PKC and the translocation of Rac-1 and ROCK2 from cytosol to membrane as well as stress fiber formation, which were markedly increased in the IL-1 beta-pretreated VSMCs but not in the P2Y(2)R-siRNA-transfected VSMCs. These results demonstrate that pro-inflammatory cytokines associated with atherosclerosis, such as can accelerate the process of atherosclerosis through the upregulation of P2Y(2)R. (C) 2015 Elsevier Inc. All rights reserved.