TCF21 and AP-1 interact through epigenetic modifications to regulate coronary artery disease gene expression [ChIP-Seq]

The majority of genetic variation associated with coronary artery disease (CAD) resides in non- coding regions that are expected to involve transcriptional and epigenetic mechanisms of gene expression. We have identified a transcriptional network downstream of the CAD associated transcription factor (TF) TCF21 and provide evidence for TCF21 colocalization and co- regulation with the activator protein-1 (AP-1) complex in disease loci. We show that TCF21 and AP-1 regulate expression of two causal CAD genes, SMAD3 and CDKN2B-AS1, in part by interactions with histone acetyltransferases and deacetylases. Genome-wide, TCF21 and AP-1 are jointly localized, regulate chromatin accessibility, and are enriched in CAD loci. These data show that the known chromatin remodeling and pioneer functions of AP-1 are a pervasive aspect of epigenetic control of transcription and thus risk in CAD associated loci, and that interaction of AP-1 with TCF21 to control epigenetic features contributes to the genetic risk in loci where they colocalize. Overall design: Human coronary artery smooth muscle cells (HCASMC) grown in serum were evaluated with an antibody to H3K27ac, or input control with siRNA of JUN, shRNA of TCF21 or control knockdown.