Our long-term goal is to understand how nuclear receptors regulate monocyte and macrophage gene expression in the context of chronic metabolic diseases, such as atherosclerosis and obesity-induced insulin resistance. Recent studies indicate that classical activation of resident macrophages by Th1-type stimuli, such as interferon gamma, plays a key pathogenic role in both atherosclerosis and obesity-induced insulin resistance. In contrast, Th2 cytokines interleukin-4 and -13 (IL-4 and IL-13) promote alternative activation of tissue macrophages to ameliorate metabolic syndrome. Notably, we have reported that the maturation of alternatively activated macrophages in tissues is absolutely dependent on the transcriptional activity of Peroxisome Proliferator Activated Receptors gamma and delta (PPAR gamma and delta), providing a mechanistic basis for the protective functions of these receptors in obesity-induced insulin resistance and atherosclerosis. In addition to their well-established functions in macrophage biology, we recently discovered that PPAR gamma and delta are also expressed in circulating mouse monocytes, the precursors of recruited and resident tissue macrophages. Moreover, PPAR gamma and delta are transcriptionally competent in monocytic cells, suggesting that these receptors might also coordinate gene expression networks in these cells. Therefore, studies proposed in the present grant application will take molecular, cellular, and genetic approaches, including monocyte- and macrophage-specific knockouts, to further investigate how PPAR gamma and delta control the maturation of monocytes and activation of macrophages in lean and obese mice. Data from these studies will greatly enhance the molecular understanding of how PPAR gamma and delta regulate monocyte and macrophage functions under physiologic and pathophysiologic conditions, leading to better utilization of their ligands for the treatment of metabolic complications of obesity, such as atherosclerosis.
The specific aims of this proposal are to: 1) Develop and validate a novel cell culture system for adoptive transfer of monocytic cells, 2) Investigate the regulatory roles of PPAR gamma and delta in monocyte biology in both mice and humans, and 3) Investigate the functions of PPARs development of advanced necrotic plaques.

Public Health Relevance

Monocytes and macrophages are heterogeneous groups of cells that take residence in almost all organs of the body. Interestingly, activation of tissue macrophages is transcriptionally controlled by the various nuclear receptors, which can ameliorate the metabolic complications of obesity. Studies in this grant application will explore the mechanisms by which nuclear receptors control the maturation of monocytes and activation of macrophages in tissues. Insights from these studies should identify new therapeutic targets for intervening in atherosclerosis in which monocytes and macrophages play a key pathogenic role.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
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Atherosclerosis and Inflammation of the Cardiovascular System Study Section (AICS)
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Liu, Lijuan
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University of California San Francisco
Schools of Medicine
San Francisco
United States
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Ganeshan, Kirthana; Chawla, Ajay (2014) Metabolic regulation of immune responses. Annu Rev Immunol 32:609-34
Mauer, Jan; Chaurasia, Bhagirath; Goldau, Julia et al. (2014) Signaling by IL-6 promotes alternative activation of macrophages to limit endotoxemia and obesity-associated resistance to insulin. Nat Immunol 15:423-30
Qiu, Yifu; Nguyen, Khoa D; Odegaard, Justin I et al. (2014) Eosinophils and type 2 cytokine signaling in macrophages orchestrate development of functional beige fat. Cell 157:1292-308
Odegaard, Justin I; Chawla, Ajay (2013) The immune system as a sensor of the metabolic state. Immunity 38:644-54
Odegaard, Justin I; Chawla, Ajay (2013) Pleiotropic actions of insulin resistance and inflammation in metabolic homeostasis. Science 339:172-7
Odegaard, Justin I; Ganeshan, Kirthana; Chawla, Ajay (2013) Adipose tissue macrophages: Amicus adipem? Cell Metab 18:767-8
Eisele, Nicholas A; Ruby, Thomas; Jacobson, Amanda et al. (2013) Salmonella require the fatty acid regulator PPARýý for the establishment of a metabolic environment essential for long-term persistence. Cell Host Microbe 14:171-82
Nguyen, Khoa D; Fentress, Sarah J; Qiu, Yifu et al. (2013) Circadian gene Bmal1 regulates diurnal oscillations of Ly6C(hi) inflammatory monocytes. Science 341:1483-8
Wynn, Thomas A; Chawla, Ajay; Pollard, Jeffrey W (2013) Macrophage biology in development, homeostasis and disease. Nature 496:445-55
Carvalheira, Jose Barreto Campello; Qiu, Yifu; Chawla, Ajay (2013) Blood spotlight on leukocytes and obesity. Blood 122:3263-7

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