David Harrison is Principal Investigator at The Jackson Laboratory. Its objectives are to investigate the genetics of aging and lifespan, seeking to understand the basic mechanisms of aging, and adult stem cells, with the goal of delaying normal aging processes. The Harrison research group investigates aging in mouse models, focusing on processes that have the potential to retard aging and prolong health. For example, one line of research investigates mutations that reduce IGF-1 and insulin function. Such mutations can increase life span and delay certain aspects of aging, especially development of cancer. They have also shown through an Intervention Testing Program (ITP) that rapamycin, an inhibitor of the mTOR pathway, extends median and maximal lifespan in mice. They are continuing their ITP research. Other focus area in Harrison's Laboratory is on hematopoietic stem cells (HSCs) and other adult stem cells, which constantly proliferate and differentiate to maintain tissue functions throughout life. If aging exhausts the function of adult stem cells, the balance between damage and repair is disrupted and tissue functions become defective. The group has found that genetic mechanisms protect hematopoietic stem cells from exhaustion in some mouse strains, and they are working to define the specific mechanisms. Their long-term goal is to promote healthful aging in humans, either by delaying normal aging processes or by minimizing or eliminating diseases of aging.