Mechanisms Underlying Adipose Tissue Thermogenesis

脂肪组织产热的机制

• 批准号: 10697843
• 负责人: Aaron Cypess
• 金额: $ 20.81万
• 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/10697843
• 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; Role; Sampling; Signal Pathway; Skeletal Muscle; Sympathomimetics; TNF gene; Testing; Thermogenesis; Time; Tissue Differentiation; Tissues; Transplantation; base; diet-induced obesity; fatty acid metabolism; genetic signature; glucose metabolism; glucose tolerance; glucose uptake; impaired glucose tolerance; improved; in vitro Model; in vivo; inflammatory marker; insulin signaling; lipidomics; mRNA Expression; medical schools; member; novel; obese patients; 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 beta3-AR agonist, stimulated BAT lipolysis and thermogenesis, and both processes were lost after silencing 3-AR expression. This study highlights that beta3-ARs in human brown/beige adipocytes are required to maintain multiple components of lipolytic and thermogenic cellular machinery and that beta3-AR agonists could be used to achieve metabolic benefit in humans. In the past year, we have expanded upon these discoveries to show that human brown and white adipocytes may be capable of generating bile acids and their precursors, a new role for these tissues in human physiology.

与波士顿Joslin糖尿病中心/哈佛医学院的Tseng博士团队合作，我们从人颈部脂肪中克隆出细胞系，并在移植到免疫缺陷裸鼠体内后，在体外和体内研究了它们的成脂分化和代谢功能。通过克隆分析和基因表达谱分析，我们在人类前脂肪细胞中发现了一组独特的基因特征，这些基因特征可以预测这些细胞在培养中成熟为脂肪细胞后的生热潜力。这些数据突出了人类BAT和WAT的细胞异质性，并为启动前脂肪细胞的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图谱，这将指导开发可用于激活人类BAT和治疗肥胖和代谢性疾病的药物化合物。 通过ATCC，我们正在从更多的仓库中开发更多的人类脂肪组织细胞群和细胞系的集合。这些将有助于丰富人类脂肪组织的功能和解剖图谱。 同时，我们测试了饮食诱导肥胖(DIO)对棕色脂肪组织(BAT)的影响。我们用普通饲料(NCD)和高脂饲料(HFD)喂养6周龄C57BL/6小鼠。另外16周后，我们测量了体脂、WAT和BAT基因的表达，糖耐量，以及胰岛素和β3-AR激动剂米雷贝格隆对葡萄糖摄取率的影响。我们看到，与NCD相比，HFD增加了体内脂肪，损害了糖耐量。WAT和BAT的炎症标志物包括肿瘤坏死因子和F4/80的mRNA水平均较高。BAT和WAT的胰岛素信号转导减少，Akt磷酸化减少。饮食标准化的蝙蝠对米拉贝格隆的葡萄糖摄取率较低。这些结果支持一种模型，在该模型中，DIO导致BAT炎症和胰岛素抵抗，导致BAT功能更广泛的损害。 最近，我们再次与曾博士合作，在小鼠和人类身上利用基于质谱学的脂质组学证明了寒冷和3-肾上腺素能刺激可以促进蝙蝠体内12-脂氧合酶(LOX)代谢物的生物合成和释放。此外，去除小鼠棕色脂肪细胞中的12-LOX会损害葡萄糖的摄取和代谢，导致体内对寒冷的迟钝适应。冷诱导的12-LOX产物12-羟基二十碳五烯酸(12-HEPE)被发现是一种巴托克因子，通过激活胰岛素样细胞内信号通路促进脂肪细胞和骨骼肌对葡萄糖的摄取，从而改善葡萄糖代谢。 谢丽尔·塞罗是该团队的高级博士后研究员，她一直在研究人类来源的棕色脂肪细胞，并表明沉默3-AR会影响产热、脂肪酸代谢和线粒体质量所必需的基因。在功能上，减少降低激动剂介导的cAMP水平、脂肪分解和生热能力的增加。此外，选择性的人类β3-AR激动剂米拉贝格隆可以刺激蝙蝠脂肪分解和产热，而在沉默3-AR表达后，这两个过程都消失了。这项研究强调，人类棕色/米色脂肪细胞中的β3-AR需要维持多种成分的脂解和生热细胞机制，并且可以使用β3-AR激动剂来实现人类代谢的益处。 在过去的一年里，我们对这些发现进行了扩展，以表明人类棕色和白色脂肪细胞可能能够产生胆汁酸及其前体，这是这些组织在人类生理学中的一个新角色。