for three different endogenous pathways that may negatively regulate PPAR activity. These mechanisms will be studied by examining their modulation of well-established in vitro and in vivo models of PPAR activation. LPL-mediated PPARa activation suggests the discrepant endothelial effects of structurally diverse fatty acids may be due to differential PPARa activation, including antagonism.
In Aim 1, PPAR activation and inhibition by specific fatty acids will be studied in vitro and in vivo, contrasting omega-3 fatty acids to saturated and trans-fatty acids. Hepatic nuclear factor 4 alpha (HNF4a) is a poorly understood but critical fatty acid- activated receptor that regulates lipid metabolism, thrombosis, and glucose control. By using the manipulations of lipid metabolism employed in our LPL/PPARa studies, we have identified novel mechanisms of HNF4a modulation and divergent responses between PPARa and HNF4a to pathways of lipid metabolism.
In Aim 2, this divergence between HNF4a and PPARa will be explored. A novel but powerful mechanism for PPAR modulation would be the existence of a direct endogenous PPAR antagonist. While symmetric cleavage of beta carotene generates natural ligands for the RXR nuclear receptor, we have identified that asymmetric beta carotene cleavage produces a specific apocarotenal that directly antagonizes PPAR responses.
In Aim 3, this direct antagonist will be characterized in vitro and in vivo. Together, these studies integrate biochemical, biologic, and in vivo models to better understand how endogenous modulation of PPAR activity may determine biologic responses. KEY PERSONNEL: Name Plutzky, Jorge, MD Gaziano, J. Michael, MD, MPH Orasanu, Gabriella, MD Rader, Daniel, MD Shoelson, Stephen, MD, PhD Ziouzenkova, Ouliana, PhD Organization Brigham and Women's Hospital Brigham and Women's Hospital Brigham and Women's Hospital University of Pennsylvania Joslin Diabetes Center Brigham and Women's Hospital Role on Project Prinicipal Investigator Collaborator Post-doctoral Fellow Collaborator Collaborator Research Associate PHS 398/2590 (Rev. 05/01) Page 154 Continuation Format Paqe Principal Investigator/Program Director (Last, first. Middle): Michel. Thomas FROM THROUGH DETAILED BUDGET FOR INITIAL BUDGET PERIOD 4/1/05 3/31/06 DIRECT COSTS ONLY PERSONNEL (Applicant organization only) % DOLLAR AMOUNT REQUESTED (omit cents) TYPE EFFORT INST. ROLE ON APPT. ON BASE SALARY FRINGE NAME PROJECT (MONTHS) PROJ. SALARY REQUESTED BENEFITS TOTALS Jorge Plutzky Principal 12 20 170,000 34,000 10,880 44,880 Investigator Ouliana Ziouzenkova Res. 12 50 50,000 25,000 8,000 33,000 Assoc. Technician Tech 12 50 28,000 14,000 4,060 18,060 Gabriela Orasanu Post-Doc 12 100 30,000 30,000 6,300 36,300 Fellow Technician Tech 12 100 28,000 28,000 8,120 36,120 131,000 37,360 168,360 SUEJTOTALS CONSULTANT COSTS """""""" """""""""""""""" rj '"""""""""""""""" EQUIPMENT (Itemize) None ' <* ?< ' r ??"""""""" ' ??- .< SUPPLIES (Itemize by category) ? * Molecular Bio. Reagents (Enzymes, transfection reagents, nuclear receptor assays): 1 1 ,200 ,'-"""""""">? - Immunoreagents (Antibodies, Western reagents, etc): 8,014 ? ~?. -r?
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