PROJECT SUMMARY/ABSTRACT The purpose of this Ruth L. Kirschstein National Research Service Award is to provide support for Ms. Sophia Mahoney, a 2nd year PhD student in Dr. Douglas Seals’ (sponsor) laboratory at the University of Colorado Boulder, to conduct research and training that will prepare her to become an independent investigator in the field of cardiovascular (CV) aging research aimed at the prevention and treatment of age- related CV diseases (CVD). As part of her proposed training plan, she aims to both refine research skills presently under development and learn a variety of new technical, conceptual, and professional skills, including the use of innovative preclinical mouse models and gaining new experiences using pharmaco-dissection and proteomic approaches. Her proposed research project seeks to investigate the efficacy of the natural food- derived senolytic fisetin for preventing arterial dysfunction in old mice and to establish senolysis as the primary mechanism underlying the beneficial effects. Senescent cells accumulate with aging, and age-related changes in circulating concentrations of senescence-associated secretory phenotype (SASP) factors have been related to CVD. However, whether these age-related changes causally impair arterial function is unknown. As such, decreasing excessive cellular senescence represents a novel therapeutic target for improving arterial function with aging. Guided by strong preliminary data, Ms. Mahoney will use established preclinical models of age-related arterial dysfunction and state-of-the-art mechanistic approaches to: Aim 1) directly compare the effects of fisetin on the arteries (nitric oxide production and reactive oxygen species bioactivity) to the gold standard experimental approach for clearing senescent cells in vivo (ganciclovir treatment in p16-3MR mice); Aim 2) determine the mechanistic role of reductions in cellular senescence in mediating the expected improvements in arterial function in old mice with fisetin treatment; and Aim 3) investigate the role of changes in circulating factors, with a focus on SASP components, as a key mechanism of fisetin-associated improvements in arterial function. The expected results will elucidate the role of fisetin-induced senolysis in improving arterial dysfunction and identify novel SASP factors as new therapeutic targets for treatment of age- related arterial dysfunction. Overall, the proposed research has the potential to address important NHLBI Strategic Vision research priorities, including: 1) investigating new pathobiological mechanisms important to the onset of CVD; and 2) identifying novel therapeutic targets to treat CVD. Dr. Seals is an internationally recognized and NIH-funded scientist with a strong history of successful mentoring in translational CV research, particularly in the emerging field of “vascular aging”. Under his supervision and with the guidance of co- mentors Drs. Zachary Clayton, Judith Campisi, Katelyn Ludwig and Thom...