Single-cell multiomic QTL mapping reveals state-dependent genetic regulation and associated gene during cellular senescence

How cellular senescence reshapes inherited regulatory effects across chromatin and transcription, and eventually contribute to non-coding risk loci of complex diseases, remains elusive. We generated single-cell multiome ATAC-RNA profiles from proliferating and replicatively senescent primary HUVECs derived from 100 genotyped donors. Alongside state-resolved eQTL and caQTL mapping, we implemented covariance-aware multivariate QTL mapping to identify chromatin accessibility-expression QTLs (caeQTLs), modeling accessibility and expression as a joint phenotype. Joint analysis recovered moderate, asymmetric and modality-distributed associations missed by single-modality scans, revealed senescence-associated regulatory programs, and prioritized candidate causal variants and effector genes at cardiovascular loci. Fine-mapping, chromatin-state annotation and heritability enrichment, together with independent SNP-to-gene algorithms, provided convergent orthogonal support. Mechanistic dissection revealed that rs2019090 modulates PDGFD expression and endothelial phenotypes through senescence-amplified, allele-specific, HMGA1-associated enhancer-promoter regulation. This study establishes senescence-resolved joint multiomic QTL mapping as a framework for narrowing the missing regulation gap in complex disease genetics.