Abstract 318: Matrix Metalloproteinase 12 is Causally Implicated in Cardiovascular Disease

Abstract

Recent evidence suggests that single nucleotide polymorphisms (SNPs) in the matrix metalloproteinase (MMP) gene cluster located at chromosome 11q22.3 are associated with large-vessel stroke. In the present study, we evaluated and extended the reported association by examining the relationship between MMPs and vascular disease in both clinical and experimental samples. Plasma concentrations of MMP-1, MMP-3, MMP-7, MMP-10 and MMP-12 were measured in 3 394 subjects with high-risk for cardiovascular disease (CVD) using the Olink ProSeek CVD array. Plasma MMP-12 concentration showed association with incident cardiovascular events (199 events over 36 months) and intima-media thickness progression over time (p=3.6x10 -5 ). The SNP variant rs1892971 was strongly associated with plasma MMP-12 concentration (p=8x10 -29 ) and weakly with susceptibility to coronary heart disease in the CardiogramplusC4D consortium study (p=8.8x10 -5 ). The same SNP was also significantly associated with MMP-12 gene expression in peripheral blood mononuclear cells using microarrays from patients with carotid atherosclerosis (n=96; p=1.8x10 -4 ). Expression of MMP-12 was strongly increased in carotid plaques (n=127) compared with undiseased arteries (n=10; p<0.0001) and in plaques from symptomatic (n=87) compared to asymptomatic patients (n=40; p=0.03) and localised to CD68+ macrophages. Using proximity ligation assay MMP-12 and elastin was demonstrated to co-interact in plaques in situ, particularly in regions with moderate to strong MMP-12 expression. Silencing of MMP-12 using siRNA in differentiated THP-1 cells indicated that MMP-12 has a role in macrophage migration. In conclusion, our study suggests that MMP-12 is a causal factor in CVD that is highly upregulated in human atherosclerotic plaques where it interacts with elastin and appears to enhance macrophage invasion.