FHL5 controls vascular disease-associated gene programs in smooth muscle cells

Abstract

Background: Genome-wide association studies (GWAS) have identified hundreds of loci associated with common vascular diseases such as coronary artery disease (CAD), myocardial infarction (MI), and hypertension. However, the lack of mechanistic insights for a majority of these loci limits translation of these findings into the clinic. Among these loci with unknown functions is UFL1-FHL5 (chr6q16.1), a locus that reached genome-wide significance in a recent CAD/MI GWAS meta-analysis. In addition to CAD/MI, UFL1-FHL5 is also implicated to coronary calcium, intracranial aneurysm, and migraine risk, consistent with the widespread pleiotropy observed among other GWAS loci. Methods: We apply a multimodal approach leveraging statistical fine-mapping, epigenomic profiling, and imaging of human coronary artery tissues to implicate Four-and-a-half LIM domain 5 (FHL5) as the top candidate causal gene. We unravel the molecular mechanisms of the cross-phenotype genetic associations through in vitro functional analyses and epigenomic profiling experiments. Results: We prioritized FHL5 as the top candidate causal gene at the UFL1-FHL5 locus through eQTL colocalization methods. FHL5 gene expression was enriched in the SMC and pericyte population in human artery tissues with coexpression network analyses supporting a functional role in regulating SMC contraction. Unexpectedly, under procalcifying conditions, FHL5 overexpression promoted vascular calcification and dysregulated processes related to extracellular matrix organization and calcium handling. Lastly, by mapping FHL5 binding sites and inferring FHL5 target gene function using artery tissue gene regulatory network analyses, we highlight regulatory interactions between FHL5 and downstream CAD/MI loci, such as FOXL1 and FN1 that have roles in vascular remodeling. Conclusion: Taken together, these studies provide mechanistic insights into the pleiotropic genetic associations of UFL1-FHL5. We show that FHL5 mediates vascular disease risk through transcriptional regulation of downstream vascular remodeling loci. These trans-acting mechanisms may account for a portion of the heritable risk for complex vascular diseases.

Smooth muscle expression of RNA editing enzymeADAR1controls vascular integrity and progression of atherosclerosis

“…To model SMC calcification in vitro, we cultured an immortalized HCASMC line under high calcium/phosphate culture conditions as has been previously reported (36). In this model, SMCs begin to form deposits that stain with Alizarin red, consistent with calcium crystals and has been proposed to represent vascular calcification (36).…”

“…To model SMC calcification in vitro, we cultured an immortalized HCASMC line under high calcium/phosphate culture conditions as has been previously reported (36). In this model, SMCs begin to form deposits that stain with Alizarin red, consistent with calcium crystals and has been proposed to represent vascular calcification (36). Following siRNA transfection for 48 hours, we cultured cells for 7 days with pro-calcification medium under low serum (1%) conditions and performed bulk RNAseq.…”

Chronic Overlapping Pain Conditions and Nociplastic Pain

“…In contrast, positional gene sets enriched for non-specific nociplastic pain genes included chr17q21, where duplication and deletion have previously been associated with syndromes involving distinctive craniofacial features, developmental delay, and cardiac symptoms (OMIM 610443, 613533), and genes at chr6q16 with cardiac phenotypes (78) and cluster headache and migraine (79).…”

“…with syndromes involving distinctive craniofacial features, developmental delay, and cardiac symptoms (Online Mendelian Inheritance in Man (OMIM) accession: 610443, 613533), and genes at chr6q16 with cardiac phenotypes 80 and cluster headache and migraine 81 .…”