Allele-Specific Regulation of Vascular Smooth Muscle Gene Expression and Apoptosis by the Blood Pressure-associated SNP rs217727

Among the two alleles of human single nucleotide polymorphism (SNP) rs217727, the G allele is associated with lower systolic, diastolic, and pulse pressure compared to the A allele. rs217727 is in exon 5 of the long non-coding RNA H19. Additionally, H19 encodes miR-675 from exon 1 and acts as miRNA sponging for miR-200a, miR-19b, etc. MRPL23, is the closest protein coding gene at 48.3 kb away. Whole blood analysis identified rs217727 as an expression quantitative trait locus for MRPL23 and troponin T3 fast skeletal type (TNNT3, 76.1kb away). This study sought to identify the effector genes and pathways of rs217727 in vascular smooth muscle cells (VSMC), which play a critical role in blood pressure (BP) homeostasis. Human induced pluripotent stem cells (iPSCs) were differentiated into VSMC’s, followed by negative selection via VE-cadherin-based purification. Chromatin conformation analysis in VSMC’s using Micro-C revealed that rs217727 shares chromatin loops with several genes in a genomic region from 220.7 kb upstream to 179.3 kb downstream of the rs217727. Isogenic iPSC lines homozygous for either the G or A allele were created using CRISPR-Cas9. Subsequently six rounds of VSMC differentiation were followed by gene expression assessment using targeted RT-qPCR. VSMCs with the A allele showed significantly reduced expression of H19 (0.73±0.05-fold relative to G allele iVSMC’s), and lymphocyte specific protein 1 (LSP1, 142.6 kb away; 0.35±0.04-fold), with a slight increase for Cathepsin D (CTSD, 231.8 kb away; 0.85±0.24-fold, n≥34, p< 0.01). Additionally, miR-675-5p and miR-675-3p werer significantly downregulated in VSMC’s with the A allele (0.69±0.06-fold and 0.69±0.05-fold, n≥15, p< 0.01). No significant expression differences were observed for MRPL23, insulin-like growth factor 2 (IGF2,141.6 kb away), Synaptotagmin 8 (SYS8, 169.9 kb away), TNNT3 (76.1kb away), or MRPS6 (different chromosome). H19 is known to regulate apoptotic pathways via miR-675 and miR-200a. Apoptotic marker genes Caspase-8 (CASP8, 0.88 ± 0.04-fold, n≥27, p< 0.01), Fas-Associated protein with Death Domain (FADD, 0.89 ± 0.04-fold, n≥15, p< 0.01) and Programmed Cell Death 4 (PDCD4, 0.68 ± 0.04-fold, n>27, p< 0.01) showed significant downregulation in VSMCs with the high blood pressure allele of rs217727. Further, TUNEL assays demonstrated a 25% reduction in apoptosis in VSMCs carrying the high BP allele (n≥15, p< 0.05). These findings suggest that rs217727 modulates local gene expression which may, in turn, influence VSMC function relevant to BP regulation. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.