FHL5 cofactor mediates vascular disease risk by regulating smooth muscle cell transcriptional networks [CUT&RUN]

Genome-wide association studies (GWAS) have identified hundreds of loci associated with vascular diseases such as coronary artery disease (CAD) and myocardial infarction (MI), and hypertension. However, the biological roles for many of these loci enriched in the vessel wall remains unknown. Among these, UFL1-FHL5 (chr6q16.1) emerged as a genome-wide significant locus in a recent CAD/MI meta-analysis. Here, we use an integrative approach leveraging human genetics, epigenomic profiling, and in vitro functional and ex vivo imaging analyses to prioritize FHL5 as the top candidate causal gene and reveal the molecular mechanisms of its pleiotropic genetic associations. Notably, FHL5 overexpression in coronary artery smooth muscle cells (SMC) increased vascular calcification and dysregulated processes related to extracellular matrix organization and calcium handling. Lastly, by mapping FHL5 binding sites genome-wide using CUT&RUN, we identified regulatory interactions with downstream disease loci having putative roles in SMC phenotypic modulation. Together, these trans-acting mechanisms may account for a portion of the heritable risk for CAD/MI and other complex vascular diseases. To identify FHL5 genome-wide binding sites, CUT&RUN experiments were performed using FHL5, CREB, H3K4me3, and H3K27ac antibodies using 250,000 HCASMC-hTERTs grown under basal conditions as input. The IgG and HCASMC-hTERT (with no FHL5 expression) samples were included as controls. We conducted at least 2 technical replicates per cell line for each antibody.  Next generation sequencing was performed on an Illumina NextSeq 2000 or Illumina NextSeq 500 instrument.