Mechanisms Underlying Adipose Tissue Thermogenesis

脂肪组织产热的机制

• 批准号: 10253761
• 负责人: Aaron Cypess
• 金额: $ 15.17万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10253761
• 关键词: Ablation; Acids; Address; Adipocytes; Adipose tissue; Adrenergic Agents; Adrenergic Agonists; Adrenergic Receptor; Agonist; Anabolism; Anatomy; Arachidonate 12-Lipoxygenase; Bile Acids; Biochemistry; Bioinformatics; Blood Pressure; Body fat; Body measure procedure; Boston; Brown Fat; C57BL/6 Mouse; COVID-19; Cardiovascular system; Cell Line; Cells; Clinical; Clinical Trials; Clone Cells; Collaborations; Collection; Corticotropin; Cyclic AMP; Data; Diabetes Mellitus; Diet; Dose; Ephedrine; Experimental Models; Failure; Fatty acid glycerol esters; Gene Expression; Gene Expression Profile; Gene Expression Profiling; Gene Targeting; Generations; Genes; Health; Heart Rate; Heterogeneity; High Fat Diet; Human; Human Cell Line; Human Cloning; Immune; Impairment; In Vitro; Inflammation; Insulin; Insulin Resistance; Leukocytes; Ligand Binding; Ligands; Lipolysis; Mass Spectrum Analysis; Mediating; Messenger RNA; Metabolic; Metabolic Diseases; Mitochondria; Modeling; Mus; Neck; Norepinephrine; Nude Mice; Obesity; Oxygen Consumption; Patients; Pharmacological Treatment; Pharmacology; Phosphorylation; Physiology; Population; Postdoctoral Fellow; Process; Respiration; Risk; Rodent; Sampling; Signal Pathway; Skeletal Muscle; Sympathomimetics; TNF gene; Testing; Thermogenesis; Time; Tissue Differentiation; Transplantation; base; fatty acid metabolism; genetic signature; glucose metabolism; glucose tolerance; glucose uptake; impaired glucose tolerance; improved; in vitro Model; in vivo; inflammatory marker; insulin signaling; mRNA Expression; medical schools; member; novel; receptor expression; response

In collaboration with Dr. Tseng's group at the Joslin Diabetes Center / Harvard Medical School in Boston, we generated clonal cell lines from human neck fat and characterized their adipogenic differentiation and metabolic function in vitro and in vivo after transplantation into immune deficient nude mice. Using clonal analysis and gene expression profiling, we identified unique sets of gene signatures in human preadipocytes that could predict the thermogenic potential of these cells once matured in culture into adipocytes. These data highlight the cellular heterogeneity in human BAT and WAT and provide novel gene targets to prime preadipocytes for thermogenic differentiation. We also used these immortalized human adipocytes to describe the adrenergic receptor expression and functional profiling that will guide the develop of pharmacological compounds that can be used to activate human BAT and treat obesity and metabolic disease. With ATCC, we are developing an additional collection of human adipose tissue cell populations and cell lines from additional depots. These will help enrich the functional and anatomical mapping of human adipose tissue. In parallel, we tested the effects of diet-induced obesity (DIO) on brown adipose tissue (BAT). We fed 6-week-old C57BL/6 mice either a normal chow diet (NCD) or a high-fat diet (HFD). After 16 additional weeks, we measured body fat, WAT, and BAT mRNA expression, glucose tolerance, and rates of glucose uptake in response to insulin and the beta3-AR agonist mirabegron. We saw that compared with NCD, HFD increased body fat and impaired glucose tolerance. Both WAT and BAT had higher mRNA levels of markers of inflammation, including TNF and F4/80. Insulin signaling in BAT and WAT was reduced, with decreased Akt phosphorylation. Diet-normalized BAT glucose uptake rates were lower in response to mirabegron. These results support a model in which DIO leads to BAT inflammation and insulin resistance, leading to a broader impairment of BAT function. More recently, working again with Dr. Tseng, we utilized mass-spectrometry-based lipidomics in mice and humans to demonstrated that cold and 3-adrenergic stimulation could promote the biosynthesis and release of 12-lipoxygenase (LOX) metabolites from BAT. Moreover, 12-LOX ablation in mouse brown adipocytes impaired glucose uptake and metabolism, resulting in blunted adaptation to the cold in vivo. The cold-induced 12-LOX product 12-Hydroxyeicosapentaenoic acid (12-HEPE) was found to be a batokine that improves glucose metabolism by promoting glucose uptake into adipocytes and skeletal muscle through activation of an insulin-like intracellular signaling pathway. Cheryl Cero, a senior postdoctoral fellow in the group has been working with human-derived brown adipocytes and showed that silencing of the 3-AR compromises genes essential for thermogenesis, fatty acid metabolism, and mitochondrial mass. Functionally, reduction lowered agonist-mediated increases in cAMP levels, lipolysis, and thermogenic capacity. Furthermore, mirabegron, a selective human 3-AR agonist, stimulated BAT lipolysis and thermogenesis, and both processes were lost after silencing 3-AR expression. This study highlights that 3-ARs in human brown/beige adipocytes are required to maintain multiple components of lipolytic and thermogenic cellular machinery and that 3-AR agonists could be used to achieve metabolic benefit in humans.

我们与波士顿哈佛医学院乔斯林糖尿病中心的 Tseng 博士团队合作，从人类颈部脂肪中产生了克隆细胞系，并在移植到免疫缺陷裸鼠体内后在体外和体内表征了它们的脂肪形成分化和代谢功能。使用克隆分析和基因表达谱，我们在人类前脂肪细胞中鉴定了一组独特的基因特征，可以预测这些细胞在培养物中成熟为脂肪细胞后的产热潜力。这些数据突出了人类 BAT 和 WAT 的细胞异质性，并为前脂肪细胞进行产热分化提供了新的基因靶点。我们还使用这些永生化的人类脂肪细胞来描述肾上腺素能受体的表达和功能分析，这将指导可用于激活人类 BAT 并治疗肥胖和代谢疾病的药理学化合物的开发。 我们正在与 ATCC 合作，从其他仓库中开发更多的人类脂肪组织细胞群和细胞系。 这些将有助于丰富人类脂肪组织的功能和解剖图谱。 与此同时，我们测试了饮食引起的肥胖（DIO）对棕色脂肪组织（BAT）的影响。 我们用正常饮食 (NCD) 或高脂肪饮食 (HFD) 喂养 6 周大的 C57BL/6 小鼠。另外 16 周后，我们测量了身体脂肪、WAT 和 BAT mRNA 表达、葡萄糖耐量以及胰岛素和 β3-AR 激动剂米拉贝隆的葡萄糖摄取率。 我们发现，与非传染性疾病相比，高频饮食增加了体脂并降低了糖耐量。 WAT 和 BAT 的炎症标志物 mRNA 水平较高，包括 TNF 和 F4/80。 BAT 和 WAT 中的胰岛素信号传导减少，Akt 磷酸化减少。米拉贝隆的饮食标准化 BAT 葡萄糖摄取率较低。 这些结果支持了一种模型，其中 DIO 会导致 BAT 炎症和胰岛素抵抗，从而导致 BAT 功能更广泛的损害。 最近，我们再次与 Tseng 博士合作，在小鼠和人类中利用基于质谱的脂质组学，证明冷刺激和 3-肾上腺素能刺激可以促进 BAT 中 12-脂氧合酶 (LOX) 代谢物的生物合成和释放。此外，小鼠棕色脂肪细胞中的 12-LOX 消融会损害葡萄糖的摄取和代谢，导致体内对寒冷的适应减弱。冷诱导的 12-LOX 产物 12-羟基二十碳五烯酸 (12-HEPE) 被发现是一种巴托因子，通过激活类胰岛素细胞内信号通路，促进脂肪细胞和骨骼肌中的葡萄糖摄取，从而改善葡萄糖代谢。 该小组的高级博士后 Cheryl Cero 一直在研究人源性棕色脂肪细胞，结果表明 3-AR 的沉默会损害生热、脂肪酸代谢和线粒体质量所必需的基因。从功能上讲，减少降低了激动剂介导的 cAMP 水平、脂肪分解和生热能力的增加。此外，米拉贝隆（一种选择性人 3-AR 激动剂）可刺激 BAT 脂肪分解和生热作用，而这两个过程在 3-AR 表达沉默后都会消失。这项研究强调，人类棕色/米色脂肪细胞中的 3-AR 是维持脂肪分解和生热细胞机制的多种成分所必需的，并且 3-AR 激动剂可用于实现人类的代谢益处。