Mechanisms of T cell inflammation in obesity-induced type 2 diabetes

肥胖引起的 2 型糖尿病中 T 细胞炎症的机制

• 批准号: 9130822
• 负责人: Nancie MacIver
• 金额: $ 35.78万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-21 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9130822
• 关键词: Adipocytes; Adipose tissue; Adult; Affect; Animals; Body Weight; Cell Count; Cell Differentiation process; Cell physiology; Cells; Cellular Metabolic Process; Data; Development; Diabetes Mellitus; Eating; Effector Cell; Energy Metabolism; Epidemic; Equilibrium; FRAP1 gene; Glucose Transporter; Health; High Fat Diet; Hormones; Immune; Inflammation; Inflammatory; Insulin Resistance; Knock-out; Knockout Mice; Leptin; Link; Lipids; Lymphocyte; Lymphoid; Mediating; Metabolic; Metabolic Diseases; Metabolic syndrome; Metabolism; Molecular; Non-Insulin-Dependent Diabetes Mellitus; Nutritional status; Obesity; Pathogenesis; Pathway interactions; Peripheral; Phenotype; Play; Population; Process; Production; Proteins; Regulatory T-Lymphocyte; Reporting; Resistance development; Risk; Role; STAT3 gene; Signal Pathway; Signal Transduction; Signaling Molecule; Staging; T cell differentiation; T-Cell Activation; T-Cell Proliferation; T-Lymphocyte; T-Lymphocyte Subsets; Testing; Visceral; Weight; cytokine; glucose metabolism; glucose uptake; hypoxia inducible factor 1; insight; knockout animal; leptin receptor; macrophage; meetings; metabolic profile; new therapeutic target; novel; novel marker; novel therapeutic intervention; oxidation; prevent; programs; response

 DESCRIPTION (provided by applicant): Obesity predisposes to both systemic and adipose-tissue inflammation that is associated with the development of metabolic syndrome, including insulin resistance leading to type 2 diabetes. In obese adipose tissue, there is an influx of immune cells, particularly macrophages and lymphocytes, which secrete inflammatory cytokines that promote this phenotype. T lymphocytes (T cells) have an early and critical role in obesity-induced inflammation, as adipose-resident T cells in obesity are activated and undergo a shift in subset differentiation, leading to increased inflammatory effector T cells (Teff) and decreased suppressive regulatory T cells (Treg), which precedes the recruitment of macrophages into adipose tissue. Understanding how T cells are differentiated and activated in obesity is a critically important step in understanding the mechanism of obesity-driven inflammation. Activation of T cells results in an increased metabolic demand to fuel T cell proliferation and cytokine production. Inflammatory Teff cells meet this increased metabolic demand by upregulating glucose uptake and metabolism, whereas Treg cells utilize a distinct metabolic program of lipid oxidation. These metabolic programs are essential for each subset; therefore, identification of factors that promote glucose metabolism may alter the Teff/Treg balance and mediate obesity-associated inflammation. We have identified a novel link between nutritional status and T cell activation and metabolism through the adipokine leptin. Leptin is secreted in proportion to adipocyte mass and is therefore increased in obesity. Leptin is well-known for its ability to regulate food intake and whole body metabolism, but it is also a pro- inflammatory cytokine, with important effects on immune cell number and function. We have now shown that leptin promotes T cell glucose metabolism to fuel Teff activation. Therefore, while T cell activation in obesity is likely altered via multiple mechanisms, increased circulating leptin may be a key factor. The objective of this proposal is to identify mechanisms by which obesity alters the Teff/Treg balance, resulting in inflammation and subsequent insulin resistance leading to type 2 diabetes. We hypothesize that obesity-associated hyperleptinemia directly promotes T cell glycolytic metabolism to drive T cell inflammation. To test our hypothesis we propose the following Specific Aims: (1) Identify the role of leptin in Teff versus Treg differentiation and metabolism and in the development of insulin resistance in obesity. (2) Examine signaling pathways by which leptin may mediate changes to T cell differentiation and metabolism to promote inflammation and insulin resistance in obesity. At the completion of this project, we will better understand the role of leptin in linking nutritional status with immune cell metabolism and differentiation in obesity. Understanding mechanisms by which T cells respond to obesity may identify novel markers and targets for the treatment of diabetes and metabolic disease.