Vascular matrix metalloproteinase-2 cleaves big endothelin-1 yielding a novel vasoconstrictor

Matrix metalloproteinase-2 (MMP-2, gelatinase A) and its tissue inhibitor ( TIMP-2) are mainly known for their roles in the (patho)physiological remode ling of the vasculature, angiogenesis, tissue repair, tumor invasion, infla mmation, and atherosclerotic plaque rupture. A mechanism of action of MMP-2 is the proteolytic breakdown of specific extracellular matrix proteins. Th e amino acid sequences in interstitial collagen (Gly-Leu/Ile) and laminin-5 (Ala-Leu) that are cleaved by MMP-2 are homologous to a region (Gly(32)-Le u(33)) within human big endothelin-1[1 to 38] (big ET-1). Big ET-1 requires cleavage to an active form to produce vasoconstriction. We tested the hypo thesis that vascular MMP-2 can cleave big ET-1, thus generating a vasoconst rictor peptide. In perfused rat mesenteric arteries with an intact endothel ium, inhibition of vascular MMP-2 with TIMP-2 reduced (by 16.2+/-4.2%) the vasoconstrictor effects of big ET-1 (50 pmol). However, when the endotheliu m was mechanically removed, TIMP-2 abolished (>90%) the vasoconstriction of big ET-1, and this effect was mimicked by an anti-MMP-2 antibody. Incubati on of big ET-1 with recombinant human MMP-2 resulted in the specific cleava ge of the Gly(32)-Leu(33) bond of big ET-1. Moreover, the resultant peptide ET-1[1 to 32] exerted greater vasoconstrictor effects than big ET-1. We co nclude that vascular MMP-2 contributes to the vasoconstrictor effects of bi g ET-1 by cleaving big ET-1 to yield a novel and potent vasoconstrictor, ET -1[1 to 32]. These data implicate, for the first time, the endogenous MMP-2 /TIMP-2 system in the regulation of vascular reactivity.