Abstract We0039: Integration of Genome-Wide Association Studies with Single Cell Chromatin Accessibility Data Identifies a Fibro-Adipogenic Progenitor (FAP) Enhancer and Mmp1 and Mmp3 as Novel Targets for PAD.

Introduction: Peripheral arterial disease (PAD), which affects more than 200 million individuals worldwide, is a complex disease caused by a myriad of environmental and poorly understood genetic factors. Genome-wide association studies (GWAS) have identified hundreds of PAD-associated loci. These associations have the potential to both uncover molecular mechanisms and identify novel drug targets. However, the translation of GWAS findings into clinical therapies for PAD patients has been limited because the target genes and causal cell types remain unknown. To address this limitation, we integrated publicly available PAD GWAS data with single-cell epigenomic data to facilitate cell type-specific annotation of candidate regulatory elements and their target genes in PAD. Methods & Results: We performed a linkage disequilibrium score regression analysis on lead single nucleotide polymorphisms from PAD GWAS data; we identified loci rs525119 to be in strong linkage disequilibrium (LD r2 0.98) with a known PAD-locus, rs566125. Next, we used a publicly available human skeletal muscle (n = 31) and our institutional PAD (n = 10) single-cell assay for transposase-accessible chromatin sequencing (scATAC-seq) dataset to demonstrate that PAD risk variant rs525119 is located in a fibro-adipogenic progenitor (FAP)-specific peak. Furthermore, we show that this peak is co-accessible with the promoter regions for Mmp1 and Mmp3. Next, we examined the genotype-tissue expression (GTEx) database and identified rs525119 as an expression quantitative trait loci (eQTL) for both Mmp1 and Mmp3. Finally, in a pre-clinical PAD mouse model, we show inhibition of Mmp1 and Mmp3 with a pan-Mmp inhibitor (batimastat) improves tissue repair in the ischemic limb. Conclusion: Collectively, these data suggest that PAD variant rs525119 creates a FAP-specific regulatory element that promotes the expression of Mmp1 and Mmp3.