Allele-specific regulation of matrix metalloproteinase-12 gene activity isassociated with coronary artery luminal dimensions in diabetic patients with manifest coronary artery disease

Both the processes of atherosclerosis and plaque rupture are indicated to b e influenced by matrix metalloproteinase (MMP) activity. We therefore searc hed for common functional variation in the matrix metalloelastase (MMP-12) gene locus that may be implicated in coronary artery disease. Single-strand conformation polymorphism analysis of DNA from healthy individuals detecte d a common polymorphism within the MMP-12 gene promoter (an A-to-G substitu tion at position -82), The frequency of the G allele was 0.19. The polymorp hism influences the binding of the transcription factor activator protein-1 (AP-1) in electromobility shift assay, A higher binding affinity of AP-1 t o the A allele was associated with higher MMP-12 promoter activity in vitro in transient transfection studies in U937 and murine lung macrophage (MALU ) cells. Phorbol 12-myristate 13-acetate (PMA) and insulin, 2 known activat ors of AP-1, increased the binding of AP-1 to the MMP-12 promoter, with hig her affinity for the A allele. In transfection experiments, both the A and the G alleles responded to insulin and PMA, the A allele showing higher pro moter activity than the G allele. Furthermore, Western blot analysis demons trated that insulin increased MMP-12 protein production. To analyze whether the -82 A/G polymorphism is associated with coronary artery disease, 367 c onsecutive patients who underwent percutaneous transluminal coronary angiog raphy with stent implantation were genotyped, In patients (n=71) with diabe tes, the A allele was associated with a smaller luminal diameter. In conclu sion, a common functional polymorphism within the MMP-12 promoter influence s coronary artery luminal dimensions in diabetic patients with manifest cor onary artery disease.