583 DNA Methylation in Marfan Syndrome and the Role of Inflammation and Oxidative Stress in the Pathogenesis of Disease

Marfan syndrome (MFS), caused by mutations in FBN1 (fibrillin-1), causes potentially lethal thoracic aortic aneurysm and left ventricular impairment. Prevalent intra-familial clinical heterogeneity indicates complex pathogenesis and the influence of modulators independent of the FBN1 variant. We hypothesized altered DNA methylation of relevant related genes will be detectable and modulate MFS CVS phenotype. Leukocyte genomic DNA (18 MFS patients; 18 matched controls) was analysed using the Infinium HumanMethylation450 BeadChip methylation array. Associations were analysed between DNA methylation and disease severity, and with echocardiographic parameters (AoD, LVEF, LVEDD). Quantitative immunohistochemistry determined relevant protein expression in aortic tissue. Differential methylation between the cohorts was observed in 4,345 CpG sites covering 2,367 genes, with 839 sites located in the promoter region. Gene ontology (GO) analysis of the 839 promoter region sites, using Database for Annotation, Visualization and Integrated Discovery (DAVID), showed enrichment of genes related to inflammation. Increased aortic interleukin (IL) expression for IL-10, IL-17, IL-36γ and IL-38 was demonstrated in MFS. The CpG site with the greatest Δ-beta between mild and severe disease cohorts was in the 3’UTR region of IL17RA (cg14112997) (Δ-beta=0.65; p<0.001), encoding the IL-17A receptor, with increased methylation associated with increasing severity. Redox changes were also implicated with methylation changes of FLJ44606 (p=0.001) and PON2 (p=0.0004) correlated with increasing AoD; CYP1A1 (p=0.008) with worsening LVEF and TP53INP1 (p=0.02) with increasing LVEDD. These observations indicate a role of inflammation in the pathogenesis of MFS, with the alterations in epigenetic regulation shown to modulate disease severity.