Abstract Body: Background: Obesity is a major driver of coronary microvascular disease (CMD), a key contributor to heart failure with preserved ejection fraction (HFpEF) and ischemia with non-obstructive coronary arteries. Endothelial cell (EC) dysfunction and chronic inflammation are central to obesity-associated CMD, yet the upstream molecular mechanisms remain poorly defined. Alternative polyadenylation (APA), a post-transcriptional mechanism that remodels 3’-UTRs to regulate mRNA stability and protein output, is an emerging regulator of inflammatory signaling, but its role in obesity-induced EC dysfunction is unknown.

Methods: We performed multi-omics profiling of ECs, including bulk-RNA-Seq and 3’-UTR-Seq, to identify obesity-responsive regulators of EC dysfunction. Human microvascular ECs (HMVECs) were used for PCF11 loss-of-function studies, microfluidic leukocyte adhesion assays, and inflammatory signaling analyses. EC-specific PCF11-sufficient and wild-type mice (n=10/group) were subjected to high-fat high-sucrose diet for 16 weeks, followed by assessment of coronary flow reserve (CFR), global longitudinal strain (GLS), and EC function (wire myography). PCF11 dependency was established using PCF11 siRNA via lipid nanoparticles.

Results: Integrated multi-omics profiling uncovered APA remodeling in obese ECs and identified suppression of PCF11 as a main driver. Loss of PCF11 shifted polyadenylation toward proximal poly(A) sites and shortened the 3’-UTR of TGF-beta activated kinase 1-binding protein 2 (TAB2) mRNA, and increased IκBα phosphorylation (80%), NF-κB p65 nuclear translocation (77%), ICAM-1 and VCAM-1 expression (2.9- and 2.2-fold, respectively), and leukocyte adhesion (65%) in HMVECs. EC-specific PCF11 sufficiency improved CFR (45%), GLS (34%), endothelium-dependent vasorelaxation (26%), and myocardial inflammation. Systemic PCF11 siRNA delivery abrogated these improvements, confirming PCF11-dependent effects.

Conclusion: Dysregulated APA is a previously unrecognized mechanism linking obesity to endothelial dysfunction and CMD. These findings identify APA machinery as a mechanistic driver of obesity-associated microvascular disease and highlight this pathway as a potential therapeutic target.