Expression of membrane-type matrix metalloproteinase in rabbit neointimal tissue and its correlation with matrix-metalloproteinase-2 activation.
Smooth muscle cell (SMC) phenotypic alteration, followed by migration and proliferation, is a prominent feature of atherogenesis and vascular neointimal formation. Despite extensive research, mechanism(s) responsible for this alteration remain unclear. Recently, matrix metalloproteinases (MMP), a family of potent proteinases, have been implicated in vascular diseases by way of extracellular matrix degradation. Of particular interest is that expression of a 72-kD MMP (MMP-2) is elevated in neointima, and inhibition of this MMP results in reduced SMC migration and proliferation, suggesting a role for MMP-2 in neointimal development. However, MMP-2 needs activation before digesting protein; the mechanism of this activation in the arterial wall is largely unexplored. A novel membrane-type MMP termed MT-MMP-1 has recently been identified, and its expression in tumor cells is concomitant with MMP-2 activation. Transfection of this MMP cDNA into mammalian cells results in activation of MMP-2. However, the importance of this MMP in various pathological situations is not clear. The present study was designed to explore the relationship between MT-MMP- 1 expression and MMP-2 activation during rabbit neointimal development. Using polymerase chain reaction, we isolated a rabbit cDNA from arterial SMC; sequence analysis indicated that it is a rabbit form ofMT-MMP-1. A segment of this cDNA was subcloned into pGEM-3 and employed to synthesize a DIG-labeled RNA probe. This probe was then used in the Northern blot analysis for MT-MMP-1 mRNA expression both in aortic tissue and in neointimal tissues developed 3, 7, 14 and 21 days after balloon catheter de-endothelialization. The results show low-level expression ofMT-MMP-1 in the normal aortic wall; expression is significantly increased in the neointimal tissues, with peak expression observed in tissues 3 days after injury. Expression of active MMP-2 was also determined using gel zymography. A close temporal expression pattern was observed between MT-MMP-1 and active MMP-2. These data verify the expression of MT-MMP-1 in arterial SMC and suggest its importance in MMP-2 activation after balloon catheter de-endothelialization.
Wang
H
H
Vascular and Cardiac Diseases, Therapeutics, Parke-Davis Pharmaceutical Research, Ann Arbor, Mich 48105, USA.
Keiser
J A
JA
D000595:Amino Acid Sequence; D000818:Animals; D001011:Aorta; D001483:Base Sequence; D015152:Blotting, Northern; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000302:isolation & purification; D004789:Enzyme Activation; D018093:Gelatinases / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000201:enzymology*; D016133:Polymerase Chain Reaction; D015347:RNA Probes; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D011817:Rabbits; D017385:Sequence Homology
D018076:DNA, Complementary; D015347:RNA Probes; D012333:RNA, Messenger; D018093:Gelatinases; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2