Fatty acid synthase (FAS) synthesizes palmitate and other fatty acids. In adults, FAS has not been thought to be physiologically important. This notion was challenged by our demonstration that FAS affects metabolism in several tissues by activating the nuclear receptor PPAR?. In liver, FAS-dependent activation is mediated in part by a phosphatidylcholine species that serves as a PPAR? ligand. FAS also drives a PPAR?- independent signaling process. Endothelial FAS deficiency results in vascular dysfunction caused by impaired palmitoylation of endothelial nitric oxide synthase (eNOS). Addition of palmitate, the direct product of FAS, does not restore defective PPAR? or eNOS signaling in the setting of FAS deficiency. Our findings suggest that FAS is compartmentalized within an integrated cassette generating signaling-competent lipids that could affect metabolic disease. The long-term objective of this application is to improve the health of people with diabetes and obesity by modulating FAS signaling functions. This project will test the hypothesis that FAS transmits physiological signals. These lipid signals are compartmentalized through discrete signaling nodes, chaperones, and covalent modification of FAS itself to impact metabolic disease.
The specific aims are: 1. To implicate phosphatidylcholine transfer protein (PC-TP) as a chaperone involved in the binding of an FAS-dependent endogenous ligand for PPAR? in the nucleus by comparing PC-TP-associated lipid spectra using PC-TP purified from livers of control mice and liver-specific FAS-deficient mice. 2. To determine if mice with tissue-specific inactivation of CEPT1 (a putative node for FAS signaling) in the liver and at the endothelium have phenotypes that mimic those of mice with tissue-specific inactivation of FAS. 3. To identify FAS-interacting proteins potentially involved in directing FAS to distinct cellular compartments and compartmentalizing its enzymatic product to discrete signaling nodes. 4. To determine if nutritionally regulated phosphorylation sites as well as other covalent modifications in FAS mediate FAS enzyme activity and cellular physiology. By establishing compartmentalized FAS as a mediator of physiological signals, this project could improve human health by identifying novel therapeutic targets for a wide range of metabolic disorders associated with diabetes and obesity.

Public Health Relevance

Diabetes, obesity, and associated diseases including fatty liver, peripheral vascular disease, stroke, heart attack, and related complications are major public health problems. These disorders are increasing in prevalence and available therapies are suboptimal. Therefore, this application is relevant to public health and to the mission of the NIH. It has a goal of identifying and validating a series of molecular targets that could be modulated to treat liver disease and vascular disease, major sources of morbidity and mortality in people with diabetes and obesity.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK076729-07
Application #
8670728
Study Section
Cellular Aspects of Diabetes and Obesity Study Section (CADO)
Program Officer
Pawlyk, Aaron Christopher
Project Start
2007-04-01
Project End
2016-04-30
Budget Start
2014-05-01
Budget End
2015-04-30
Support Year
7
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Washington University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Semenkovich, Clay F (2017) We Know More Than We Can Tell About Diabetes and Vascular Disease: The 2016 Edwin Bierman Award Lecture. Diabetes 66:1735-1741
Zayed, Mohamed A; Wei, Xiachao; Park, Kyoung-Mi et al. (2017) N-Acetylcysteine accelerates amputation stump healing in the setting of diabetes. FASEB J 31:2686-2695
Wei, Xiaochao; Song, Haowei; Yin, Li et al. (2016) Fatty acid synthesis configures the plasma membrane for inflammation in diabetes. Nature 539:294-298
Funai, Katsuhiko; Lodhi, Irfan J; Spears, Larry D et al. (2016) Skeletal Muscle Phospholipid Metabolism Regulates Insulin Sensitivity and Contractile Function. Diabetes 65:358-70
Rajagopal, Rithwick; Bligard, Gregory W; Zhang, Sheng et al. (2016) Functional Deficits Precede Structural Lesions in Mice With High-Fat Diet-Induced Diabetic Retinopathy. Diabetes 65:1072-84
Izawa, Takashi; Rohatgi, Nidhi; Fukunaga, Tomohiro et al. (2015) ASXL2 Regulates Glucose, Lipid, and Skeletal Homeostasis. Cell Rep 11:1625-37
Lodhi, Irfan J; Wei, Xiaochao; Yin, Li et al. (2015) Peroxisomal lipid synthesis regulates inflammation by sustaining neutrophil membrane phospholipid composition and viability. Cell Metab 21:51-64
Lodhi, Irfan J; Semenkovich, Clay F (2014) Peroxisomes: a nexus for lipid metabolism and cellular signaling. Cell Metab 19:380-92
Wei, Xiaochao; Song, Haowei; Semenkovich, Clay F (2014) Insulin-regulated protein palmitoylation impacts endothelial cell function. Arterioscler Thromb Vasc Biol 34:346-54
Hsu, Fong-Fu; Lodhi, Irfan J; Turk, John et al. (2014) Structural distinction of diacyl-, alkylacyl, and alk-1-enylacyl glycerophosphocholines as [M - 15]? ions by multiple-stage linear ion-trap mass spectrometry with electrospray ionization. J Am Soc Mass Spectrom 25:1412-20

Showing the most recent 10 out of 38 publications