Peripheral versus central IGF-1 action in the modulation of energy balance and lo

DESCRIPTION (provided by applicant): The immediate career goal of this candidate is to expedite the research currently being conducted as part of his postdoctoral training and to enhance his career development to enable his successful transition to an independent career in aging research. The current and proposed research is focused on distinguishing the central and peripheral effects of IGF-1 on energy balance, insulin action, healthy aging and longevity. As such, this proposal will require that the candidate develops and enhances his training in both genetics and neuroscience in order to successfully engage some facets of this proposal. In collaboration with his mentor, a 5-year career development plan has been designed which in the short-term will focus on intensive course work and hands-on training in genetics and neurobiology, and a mentoring committee of neuroscientists that will help to oversee the candidate's research and training. The long-term career goals of this proposal are to enable the candidate, as a new principal investigator, to secure protected time to develop his research team, to enhance his ability to train fellows and students, establish new collaborations and develop a novel line of research which produces strong grant proposals to secure independent funding. The candidate and his lab have recently uncovered remarkable positive effects of central IGF-1 action including improved peripheral insulin action and selective depletion of visceral fat, suggesting novel actions that are favorable for aging. This is in contrast to peripheral IGF-1, where among its good effects are also 'bad'effects, such as raising cancer risk. In this proposal, we will attempt to further dissect the 'good'and 'bad'effects of IGF-1 on aging, including central versus peripheral effects. The overall hypothesis of the research plan is that healthy aging and longevity is best achieved by increasing IGF-1 action in the hypothalamus to reap the 'good'effects while decreasing it in the periphery to minimize the 'bad'effects, namely cancers. Ultimately, these studies may yield important new insights regarding the complex role of IGF-1 on health and aging with relevance to humans. The candidate has devised three specific aims to be performed during the award period in order to test the overall hypothesis. Aim 1 of this proposal will focus on distinguishing between the central versus peripheral effects of acute IGF-1 action in regulating peripheral glucose metabolism with aging and will work toward establishing the mechanism(s) in the hypothalamus utilizing a combination of strategies including the use of novel genetically-engineered mice. Aim 2 of this proposal will focus on distinguishing between the central and peripheral effects of chronic IGF-1 action in regulating glucose and energy homeostasis with aging and will utilize both the rat model and a mouse model of inducible IGF-1 overexpression in the brain. The goal of Aim 3 will be to study the lifelong effects of chronic central IGF-1 overexpression by lentivirus targeted to the mediobasal hypothalamus and/or lifelong peripheral IGF-1 receptor blockade on healthy aging and longevity in rats. At the conclusion of the K99/R00 award, the candidate expects to have achieved his short-term and long-term career goals and to have elucidated novel and significant mechanisms relevant to IGF- 1 action and aging. PUBLIC HEALTH RELEVANCE: Project Narrative In model organisms, reduced insulin/IGF signaling is associated with improved longevity, but in humans, is paradoxically associated with insulin resistance, osteoporosis, cardiovascular disease and visceral obesity, We have recently uncovered novel positive effects of central IGF-1 action on peripheral metabolism and suggest that strategies designed to "tip the balance" of IGF-1 action from peripheral to central may maximize the 'good'effects of IGF-1 while minimizing cancer risk to promote healthy aging and longevity.