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Genes Cells. 2003 Mar;8(3):225-34.

Matrix metalloproteinase-12 gene expression in human vascular smooth muscle cells.

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1
Department of Pathology, Institute of Basical Medical Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.

Abstract

BACKGROUND:

Matrix metalloproteinases (MMPs) play an important role in smooth muscle cell (SMC) migration and proliferation during vascular remodelling. To investigate the expression of MMP-12 by SMCs, we examined the protein secretion and mRNA expression of MMP-12 by cultured medial SMCs and intimal SMCs derived from human aortic atherosclerotic lesions. To further elucidate the molecular mechanism for MMP-12 expression in SMCs, we determined the sequence requirements for MMP-12 gene transcriptional activity.

RESULTS:

Cultured medial SMCs and intimal SMCs showed substantial MMP-12 expression at both the protein and mRNA levels. A series of 5'-deletion and site-directed mutants of the human MMP-12 promoter demonstrated that an AP-1 site spanning -81 to -75 bp was critical for the MMP-12 promoter activity in SMCs. An electrophoretic mobility shift assay confirmed the AP-1 binding activity in SMCs and showed that the protein bound to the AP-1 site consisted predominantly of c-Jun, JunD and Fra-1. Two structurally different inhibitors of phosphatidylinositol 3-kinase, wortmannin and LY294002, inhibited MMP-12 transcriptional activity and AP-1 binding.

CONCLUSION:

These results indicated the expression of MMP-12 in vascular SMCs and showed that the MMP-12 gene expression was dependent on the AP-1 binding activity. Phosphatidylinositol 3-kinase signalling may be involved in MMP-12 transcriptional activation through AP-1 binding activity.

PMID:
12622720
[Indexed for MEDLINE]
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