The applicant's long-term career objective is to develop into an independent investigator studying the role of oxidative stress in the aging myocardium. In the current research plan, the applicant has proposed to learn new techniques in single myocyte mechanics and mass spectrometry at Boston University School of Medicine. For his early career development, the applicant has assembled a team of leading experts in the field of oxidative stress, proteomics research, myocyte mechanics, and biogerontology. At the end of the award period, the applicant will have acquired invaluable training which will allow him to develop and critically test new hypotheses central to biogerontology research. One of the hallmarks of aging is an increase in the ventricular passive stiffness leading to diastolic heart failure. With advancing age, the cellular redox state is shifted towards increased formation of reactive oxygen species (ROS). The giant elastic protein titin is the major determinant of passive mechanical properties of the cardiomyocyte. With progressive aging, post-translational oxidative modification of the elastic domain of titin could decrease cardiomyocyte compliance, and thus contribute to the diastolic dysfunction seen in aging myocardium. The overall goal of this research proposal is to test the hypothesis that age-associated accumulation of posttranslationally oxidized titin contributes to diastolic dysfunction with age.
The first aim will test if myocyte diastolic properties are redox sensitive. Freshly isolated myocytes from adult and aging mouse hearts will be treated with or without ROS generators, skinned, and titin mechanics will be assessed.
The second aim will test if aging induces post-translational oxidation of the elastic domain of titin. Titin will be isolated from adult and aging mouse hearts and processed for mass spectrometry.
The third aim will test if pharmacological antioxidant treatment in aging mice reverses oxidative modification of titin and improves diastolic function.
The fourth aim will test if mechanisms involved in proteolytic processing of titin are impaired with aging.
