RESUMO
Increases in matrix metalloproteinases (MMPs) at atherosclerotic lesions are involved in the migration of smooth muscle cells (SMCs) into the intima and to the rupture of plaques, being implicated in the progression of atherosclerosis. The present study examined the mechanisms underlying the production of MMP-1, interstitial collagenase-1, induced by oxidized low-density lipoprotein (oxLDL) and 4-hydroxynonenal (4-HNE), factors proposed to play a pivotal role in atherogenesis, in human coronary SMCs. oxLDL promoted the production of MMP-1 with the preceding phosphorylation of extracellular signal-regulated kinase (ERK) 1/2. Immunoprecipitation of platelet-derived growth factor receptor beta (PDGFR-beta) revealed that oxLDL induced tyrosine phosphorylation of the receptor. Inhibition of the activation of PDGFR-beta and ERK1/2 resulted in a suppression of the production of MMP-1. Consistently, 4-HNE also elicited the production of MMP-1 with the preceding phosphorylation of PDGFR-beta and ERK1/2. The 4-HNE-induced production of MMP-1 was prevented when the activation of PDGFR-beta and ERK1/2 was inhibited. The present results suggest that the activation of PDGFR-beta and ERK1/2 is involved in the production of MMP-1 in oxLDL- and 4-HNE-stimulated human coronary SMCs.