The British Journal of Pharmacology (2009), 156, 846–856

The integrin α2β1agonist, aggretin, promotes proliferation and migration of VSMC through  NF-kB translocation and PDGF production

Ching-Hu Chung, Kuan-Ting Lin, Chien-Hsin Chang, Hui-Chin Peng and Tur-Fu Huang

Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan

摘要

Background and purpose: During the development of atherosclerotic plaques, vascular smooth muscle cells (VSMCs) migrate from the media to the intima through the basement membrane and interstitial collagenous matrix, and proliferate to form neointima. Here, we investigate the mechanism of VSMC migration and proliferation caused by aggretin, a snake venom integrin a2b1 agonist.Experimental approach: Cultures of rat and human VSMCs were treated with aggretin and the signal transduction pathways induced by this agonist were examined by Western blotting, immunoprecipitation and electrophoretic mobility shift assay techniques.Key results: Aggretin-induced VSMC proliferation was blocked by a monoclonal antibody (mAb) against integrin a2 (AII2E10) or against the platelet-derived growth factor receptor (PDGFR)-b. Proliferation was also blocked by inhibition of the tyrosine kinase Src with PP2, phospholipase C (PLC) with U73122, extracellular signal-regulated kinase (ERK) with PD98059 or nuclear factor-kappa B (NF-kB) activation with pyrrolidine dithiocarbamate (PDTC). VSMC migration towards immobilized aggretin was increased in a modified Boyden chamber and this effect was blocked by a2b1-Src-PLC-MAPK axis inhibitors, but not by PDTC, PDGFR-b mAb, or a phosphoinositide-3 kinase inhibitor, LY294002. Aggretin stimulated the phosphorylation of PDGFR-b, Src and ERK in a time-dependent manner. NF-kB translocation and platelet-derived growth factor (PDGF)-BB production were also observed. The ERK activation, NF-kB translocation and PDGF-BB production were blocked by PP2, U73122 and PD98059.Conclusions and implications: Aggretin induces VSMC proliferation and migration mainly through binding to integrin a2b1, and subsequently activates Src, PLC and ERK pathways, inducing NF-kB activation and PDGF production.British Journal of Pharmacology (2009) 156, 846–856; doi:10.1111/j.1476-5381.2008.00095.x; published online 23 February 2009.

关键字： aggretin; integrin a2b1; smooth muscle cell; NF-kB; PDGF

文中提及的产品

FITC was fromMolecular Probes (USA); Collagen type I, MTT, pyrrolidine dithiocarbamate (PDTC), LY294002, PD98059 and BSA were from Sigma Co., (USA); PP2 was obtained from Calbiochem (San Diego, CA, USA); U73122 was obtained from Calbiochem. (La Jolla, CA, USA); DMEM, FBS and all culture reagents were purchased from Gibco BRL (USA); RNAi-Mate transfection reagent, integrin a2 siRNA and non-targeting siRNA were obtained from MDBio Inc. (Taipei, Taiwan).