Abstract 13603: Inhibition of Exercise-Regulated Long Noncoding RNA SALTe1 Reverses Vascular Aging and Age-Related Cardiac Dysfunction

Abstract

Rationale: Age is a major risk factor for cardiovascular disease. Recent work suggests vascular aging is an important determinant of longevity and end-organ function, although its role in age-related cardiac dysfunction and how exercise mitigates these phenotypes remain unclear. Objective: To identify exercise-regulated, cardiac long noncoding RNAs (lncRNAs) that modulate vascular aging. Methods and Results: Twenty-month-old mice underwent voluntary wheel running for eight weeks. RNAseq identified a novel set of lncRNAs altered in exercised aged hearts, termed S enescence A ssociated L ncRNA T ranscripts in E xercise (SALTes). SALTe1 was conserved and primarily expressed in endothelial cells (ECs). SALTe1 increased in aged hearts but decreased with exercise. Myocardial perfusion and CD31 positive cells were reduced in 20-month-old vs 10-week-old mice while EC senescence (CD31 and p16 or γH2AX double-positive cells) and cardiac diastolic dysfunction increased (p<0.05 for all). In 20-month-old mice, SALTe1 inhibition using antisense GapmeR or EC-specific knockdown in CAS9-mice reversed multiple hallmarks of vascular aging. Recovery from hindlimb ischemia improved (post-surgery day 28 perfusion ratio, Control: 0.58±0.03 vs GapmeR: 0.73±0.03, p=0.04, n=12/group) and aortic stiffness was reduced to levels seen in young animals. Myocardial perfusion (time-to-peak, Control: 2.585±0.08 vs GapmeR: 2.048±0.11 seconds, p=0.03, n=12/group) improved. Cardiac EC number increased, and EC senescence decreased (p<0.05 for all). Inhibition of SALTe1 reduced E/E’ (-20.16±1.60 vs -15.4±1.10, p=0.04, n=12/group) and increased global longitudinal strain (-15.88±0.84 vs 20.66±1.02, p=0.02, n=12/group). Mechanistic studies in vitro and in vivo revealed that SALTe1 works through regulation of Poly (ADP-Ribose) Polymerase Family Member 9 (PARP9) and RNA-binding protein with multiple splicing (RBPMS). Conclusions: SALTe1 regulates EC senescence through PARP9 and RBPMS. SALTe1 inhibition reverses multiple hallmarks of vascular aging and improves age-related cardiac dysfunction. These findings suggest a primary role for EC senescence in age-related cardiac dysfunction and identify SALTe1 as a potential new therapeutic target.