Abstract 9085: Matrixmetalloproteinase-12 Regulates the Antiviral Immune Response During Viral Myocarditis Through Interaction With Gene Regulatory Regions
Matrix Metalloproteinase (MMP)-12 activity has been attributed to cleavage of cytokines, and digestion of extracellular matrix components related to the pathogenesis of diverse conditions, including atherosclerosis and aortic aneurysms. We hypothesise that a major role for MMP-12 is its regulation of gene expression during the innate antiviral immune response, controlling the secretion of alpha interferon (IFN-α) during enterovirus induced myocarditis. We employed an MMP-12 knockout mouse model of enteroviral myocarditis to determine the role of MMP-12 during the antiviral response. Electromobility shift assay (EMSA), Chromatin immunoprecipitation PCR (ChIP) and ChIP combined with Illumina-Solexa sequencing (ChIP-seq) were used to analyse the regions of the human genome bound by MMP-12 under control and virus infected conditions. Traditional immunofluorescence microscopy and molecular biology approaches were also used to confirm the results of the genomic ChIP studies. Coxsackievirus type-B3 (CVB3) infected MMP-12 knockout mice (KO) exhibited high viral loads and mortality 3 days post infection, with low plasma IFN-α concentrations in comparison to wild-type (WT) counterparts. However, IFN-α accumulation within KO cells in multiple organs suggested that its secretion was inhibited in the absence of MMP-12. While elucidating the IFN-α secretion defect we discovered that MMP-12 was controlling the expression of genes involved in the secretion of IFN-α. Through chromatin immunoprecipitation PCR (ChIP) combined with Illumina-Solexa sequencing (ChIP-seq), and electromobility shift assay (EMSA) we identified MMP-12 binding to the IκB-α promoter, the exons of Psme3 (REGγ) and Sparcl1, including other sites within the human genome. Strong ‘hits’ identified by ChIP-seq were validated using Western blot and immunohistochemistry. In conclusion, our results suggest that MMP-12 regulates the secretion of IFN-α through regulation of gene expression during viral myocarditis.
- © 2010 by American Heart Association, Inc.