A major goal of this laboratory is to understand the molecular mechanisms by which the nuclear receptor peroxisome proliferator-activated receptor ? (PPAR?) regulates metabolism. PPAR? is the master regulator of adipocyte biology and has important metabolic and anti-inflammatory effects in macrophages. It is also the major target of thiazolidinedione (TZD) drugs that have unique abilities to reverse insulin resistance. A major goal of the present proposal is to understand how PPAR? and TZDs function at the nexus of dietary and genetic influences on adipocyte and macrophage biology in obesity and diabetes.
Specific Aim 1 is to understand the role of adipose PPAR? in metabolic dysfunction and its treatment by mining the convergence of diet, antidiabetic drugs, and genetics. We will use state-of-the-art genome-wide approaches and mutational analysis to determine the mechanisms of convergence of diet, drugs, and genetics in metabolic disease.
Specific Aim 2 is to determine the transcriptional and cellular mechanisms by which PPAR? in adipose macrophages contributes to the antidiabetic effects of TZDs. We will elucidate the PPAR?-dependent effects of TZDs on oxidative metabolism of peritoneal and adipose tissue macrophages (ATMs), and determine whether these effects on ATMs occur in vitro and in vivo. The mechanism of these effects will be determined using genome-wide approaches and mutational analysis.
Specific Aim 3 is to delineate genomic modulators of TZD action and PPAR? function in human adipose tissue and macrophages. We will determine individual-specific effects of natural genomic variation on adipocyte TZD responsiveness, and the underlying molecular mechanisms. This approach will also be applied to human macrophages, including ATMs, to determine the extent and importance of natural genetic variation in determining the actions of TZDs and PPAR? in macrophages. Together, using innovative approaches, we will address major questions about the molecular mechanisms underlying gene-environment interactions that are implicated in individual differences in obesity, diabetes, and the response to antidiabetic drugs. Our focus on adipose tissue and macrophages is appropriate given the established importance of these tissues in obesity and diabetes, and the effects of TZDs on these tissues. Our innovative genome-wide and systemic approaches will also provide fundamental insight into the molecular mechanisms underlying tissue-specific and individual-specific effects of transcription factors. Studies of human adipocytes and macrophages will determine the extent of translatability of the mouse findings, and provide insights that will inform strategies for personalized and precision approaches to the treatment of metabolic and inflammatory diseases. This knowledge will thus shed new light on the transcriptional and epigenomic control of adipocyte and macrophage biology and organismal metabolism, with translational relevance including the potential to lead to new and more selective insulin-sensitizing agents to combat the epidemics of obesity and diabetes in modern society.

Public Health Relevance

This project focuses on the interplay of diet, drug therapies, and genetic factors in obesity and diabetes. The nuclear receptor PPAR? is required for fat cells to develop and function, and is the target of antidiabetic drugs, and we are studying its function in obesity and diabetes in different mouse strains and humans. The findings will enhance our ability to provide personalized, precision medicine to combat the epidemic of metabolic disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK049780-25
Application #
9701181
Study Section
Molecular and Cellular Endocrinology Study Section (MCE)
Program Officer
Silva, Corinne M
Project Start
1995-07-01
Project End
2021-05-31
Budget Start
2019-06-01
Budget End
2020-05-31
Support Year
25
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
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Zhang, Yinxin; Dallner, Olof Stefan; Nakadai, Tomoyoshi et al. (2018) A noncanonical PPAR?/RXR?-binding sequence regulates leptin expression in response to changes in adipose tissue mass. Proc Natl Acad Sci U S A 115:E6039-E6047
Hill, David A; Lim, Hee-Woong; Kim, Yong Hoon et al. (2018) Distinct macrophage populations direct inflammatory versus physiological changes in adipose tissue. Proc Natl Acad Sci U S A 115:E5096-E5105
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Soccio, Raymond E; Li, Zhenghui; Chen, Eric R et al. (2017) Targeting PPAR? in the epigenome rescues genetic metabolic defects in mice. J Clin Invest 127:1451-1462
Lazar, Mitchell A (2017) Maturing of the nuclear receptor family. J Clin Invest 127:1123-1125
Jager, Jennifer; Wang, Fenfen; Fang, Bin et al. (2016) The Nuclear Receptor Rev-erb? Regulates Adipose Tissue-specific FGF21 Signaling. J Biol Chem 291:10867-75
Ferrannini, Giulia; Namwanje, Maria; Fang, Bin et al. (2016) Genetic backgrounds determine brown remodeling of white fat in rodents. Mol Metab 5:948-58
Soccio, Raymond E; Chen, Eric R; Rajapurkar, Satyajit R et al. (2015) Genetic Variation Determines PPAR? Function and Anti-diabetic Drug Response In Vivo. Cell 162:33-44
Cohen, Daniel M; Won, Kyoung-Jae; Nguyen, Nha et al. (2015) ATF4 licenses C/EBP? activity in human mesenchymal stem cells primed for adipogenesis. Elife 4:e06821

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