Dissecting PKA activation of mTORC1 and its function in adipose tissue

剖析 mTORC1 的 PKA 激活及其在脂肪组织中的功能

• 批准号: 10219236
• 负责人: SHEILA COLLINS
• 金额: $ 45.06万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-22 至 2023-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10219236
• 关键词: Adipocytes; Adipose tissue; Alanine; Amino Acids; Antibodies; Area; Aspartate; Behavioral; Biochemical; Biogenesis; Biological; Body fat; Body mass index; Brown Fat; CRISPR/Cas technology; Calories; Catecholamines; Cell Culture Techniques; Cell model; Cells; Chronic Disease; Clinical; Clothing; Complex; Country; Cyclic AMP; Cyclic AMP Receptor Protein; Cyclic AMP-Dependent Protein Kinases; Data; Data Set; Desire for food; Development; Disease; Endocrine System Diseases; Energy Metabolism; Engineering; Epidemic; Event; FDA approved; FRAP1 gene; Fatty Acids; Fatty acid glycerol esters; Follow-Up Studies; Generations; Genes; Genetic; Genetic Transcription; Glucose; Goals; Growth Factor; Human; In Vitro; Insulin; Insulin Resistance; Intervention; Investigation; Knock-in; Knowledge; Laboratory Animals; Life Style; Lipolysis; Longevity; Mechanics; Metabolic; Metabolic Diseases; Metabolic syndrome; Metabolism; Mitochondria; Mitogen-Activated Protein Kinases; Modeling; Molecular; Mus; Mutation; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Overweight; PPAR gamma; Pathway interactions; Peripheral; Phosphoproteins; Phosphorylation; Phosphorylation Site; Phosphotransferases; Physiological; Population; Process; Production; Proteins; Proteomics; Protons; Public Health; Raptors; Receptor Activation; Regulation; Resistance; Respiration; Ribosomal Protein S6 Kinase; Risk; Rodent; Role; Route; Safety; Scanning; Signal Pathway; Signal Transduction; Sirolimus; Site; Source; Stable Isotope Labeling; Sympathetic Nervous System; Techniques; Technology; Testing; Therapeutic; Thermogenesis; Tissues; Weight Gain; Work; absorption; beta-adrenergic receptor; cell type; comorbidity; comparative; cost; experimental study; fat burning; fighting; gain of function; gain of function mutation; health economics; improved; in vivo; inhibitor/antagonist; insight; insulin sensitivity; kinase inhibitor; loss of function mutation; novel; novel strategies; obesity treatment; p38 Mitogen Activated Protein Kinase; phosphoproteomics; prevent; programs; reconstitution; transdifferentiation; uncoupling protein 1

Project Summary: Obesity is at epidemic proportions in the US. Over 60% of the population is either overweight (Body Mass Index [BMI] ≥25 to <30 kg/m2) or obese (BMI ≥30 kg/m2), placing them at risk for a large number of chronic diseases, including insulin resistance, metabolic syndrome, and type 2 diabetes. The annual costs of obesity exceed $100 billion, making it one of the most significant public health and economic issues facing the country. Unfortunately, the treatment of obesity is unsatisfactory. Lifestyle and behavioral approaches have a modest, and often transient, effect while FDA-approved therapeutic options targeting appetite or fat absorption have poor tolerability and, in some cases, safety concerns. Thus, there is a critical need for novel approaches to treat obesity. Agents acting via peripheral mechanisms to increase energy expenditure would be valuable. The sympathetic nervous system (SNS) is well-known as an activator of brown adipose tissue (BAT) and the “browning” of cells in white adipose tissue (WAT) depots to increase uncoupled mitochondrial respiration and energy expenditure. Our earlier work established a signaling cascade from β-adrenergic receptors (βARs)  cAMP  protein kinase A (PKA)  p38 MAP kinase (MAPK) to drive the transcription of brown adipocyte genes such as uncoupling protein-1 (UCP1), PPAR-gamma coativator-1α (PGC-1α), and the broader program of mitochondrial biogenesis. We have discovered that the mTOR complex-1 (mTORC1) components mTOR and Raptor are phosphorylated by PKA. This is a highly novel observation, since the `canonical' pathway to mTORC1 is through growth factors and insulin. From in vivo studies in mice we find that blockade of mTORC1 with rapamycin, or genetic deletion of Raptor specifically in adipose tissue, suppresses the ability of the βAR pathway in increase the amount of UCP1-expressing `beige' adipocytes within white fat depots, and dampens UCP1 expression and respiration in interscapular brown fat. The ability of laboratory animals and humans to expand these `beige' adipocytes is closely correlated with resistance to weight gain and improved insulin sensitivity. We have identified the phosphorylation sites on mTOR and Raptor and propose to test the physiological consequences of cells and mice in which Ser791 of Raptor is changed to either Alanine (loss-of-function mutation) or Aspartate (gain-of-function) by engineering a `knock-in' genetic construct. Since we now show that there are two distinct routes to activation of mTORC1, we are also taking an unbiased proteomic approach to identify the unique phosphorylation substrates of mTOR resulting from PKA activation vs insulin. Altogether, these experiments will shed important mechanistic and physiological insight into the steps needed for `beige' cell expansion, as well as the broader ability of the PKA mTORC1 pathway to function in other cell types.

项目总结:

项目成果

Exercise performance is not improved in mice with skeletal muscle deletion of natriuretic peptide clearance receptor.

• DOI: 10.1371/journal.pone.0293636
• 发表时间: 2023
• 期刊: PloS one
• 影响因子: 3.7

Protein kinase D1 (Prkd1) deletion in brown adipose tissue leads to altered myogenic gene expression after cold exposure, while thermogenesis remains intact.

• DOI: 10.14814/phy2.15576
• 发表时间: 2023-02
• 期刊: Physiological reports
• 影响因子: 2.5

Unknown actor in adipose tissue metabolism hiding in plain sight.

隐藏在众目睽睽之下的脂肪组织代谢中的未知演员。

• DOI: 10.1073/pnas.1911468116
• 发表时间: 2019
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1
• 作者: Collins,Sheila