Abstract MP42: Macrophage Chromatin Remodeling Complex Subunit Baf60a In Atherosclerosis

Objectives: Atherosclerosis is a primary medical concern due to the increasing prevalence and lack of effective treatment that reverses the disease progression. While multiple genetic mutations/variations have been associated with atherosclerotic risk, the development of atherosclerosis in response to risk factors is also contributed by factors at the epigenetic and chromatin level. The SWI/SNF chromatin remodeling complex alters DNA accessibility and chromatin structure to modulate gene expression in response to external and internal cellular environments, potentially serving as an underexplored compartment of CVD and atherosclerosis development. Approach and Results: In an effort to identify key chromatin remodeling compartments involved in atherosclerotic foam cell formation, primary bone marrow-derived macrophages (BMDMs) were exposed to a pro-atherogenic environment, specifically to oxidized Low-density lipoprotein (oxLDL). We observed drastically and time-dependent decrease in the protein abundance of BAF60a, a transcription factor interacting subunit of the SWI/SNF chromatin remodeling complex. Macrophage-specific Baf60a deletion in ApoE deficient mice showed over 30% increase in aortic plaque formation after 16-weeks of western diet feeding (N=12, p=0.0097). Integrated analysis of RNA-seq and ATAC-seq regulatory network in oxLDL treated BAF60a deficient BMDMs identified a shift of chromatin accessibility, transcription factor footprint, and a reshape in gene expression patterns that regulate extracellular matrix organization, focal adhesion, integrin signaling, inflammation, and lead to foam cell formation which ultimately contribute to the atherosclerotic plaque build-up. Conclusions: Our data demonstrated the role of macrophage BAF60a in atherogenesis and suggested a potential therapeutic target to treat atherosclerosis, presumably by compensating for the loss of Baf60a.