CaMKK2 in macrophages promotes obesity-induced insulin resistance and inflammation

巨噬细胞中的 CaMKK2 促进肥胖引起的胰岛素抵抗和炎症

• 批准号: 10360487
• 负责人: Andrea Ortiz
• 金额: $ 4.68万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-22 至 2023-08-21
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10360487
• 关键词: Ablation; Adipose tissue; Adopted; Anti-Inflammatory Agents; Biological Assay; Bone Marrow; Ca(2+)-Calmodulin Dependent Protein Kinase; Calcium; Calmodulin; Cells; Chronic; Citric Acid Cycle; Clinical; Data; Development; Diet; Disease; Environment; Enzymes; Equilibrium; Exhibits; Fatty Acids; Fatty Liver; Genetic; Genus Hippocampus; Glucose; Glycolysis; Goals; High Fat Diet; Home; Homeostasis; Hypertension; In Vitro; Individual; Infiltration; Inflammation; Inflammatory; Inflammatory Response; Innate Immune Response; Insulin; Insulin Resistance; Knock-out; Knockout Mice; Laboratories; Liver diseases; Liver neoplasms; Mass Spectrum Analysis; Metabolic; Metabolic Diseases; Metabolic dysfunction; Metabolic syndrome; Metabolism; Microscopy; Mitochondria; Molecular; Morphology; Mus; Myelogenous; National Institute of Diabetes and Digestive and Kidney Diseases; Nature; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Palmitates; Pathway interactions; Performance; Peripheral; Peritoneal Macrophages; Pharmacology; Phosphorylation; Phosphorylation Site; Phosphotransferases; Physiological Processes; Physiology; Population; Process; Proteins; Radiolabeled; Recombinants; Refractory; Regulation; Role; Signal Transduction; Source; Stimulus; Stress; Testing; Therapeutic; Therapeutic Intervention; Tissues; Tracer; United States National Institutes of Health; base; cancer initiation; comorbidity; diet-induced obesity; experimental study; feeding; improved; in vivo; inflammatory marker; insulin sensitivity; long chain fatty acid; macrophage; new therapeutic target; non-alcoholic fatty liver disease; novel; oxidation; pandemic disease; preference; programs; response; sensor; therapy outcome; tool; transcriptome sequencing; tumor growth; tumor progression

Project Summary/Abstract The obesity pandemic is a growing crisis that predisposes afflicted individuals to comorbidities of the metabolic syndrome including hypertension, Type 2 diabetes and liver disease. Clinically, obesity is defined as a low-grade inflammatory disease that is influenced by macrophage infiltration and activation. Resolving this perturbed inflammatory response could be a means by which the onset and progression of metabolic syndrome is circumvented. Activation of the calcium/calmodulin kinase cascade has been implicated in abnormal metabolic processes and a contributor to diet-induced obesity. We identified that Ca2+/Calmodulin-Dependent Protein Kinase Kinase 2 (CaMKK2) is highly expressed in macrophages and is synergistically activated by Ca2+ and long-chain fatty acids, two signals that are elevated during obesity. We have shown that mice devoid of CaMKK2 are refractory to diseases typically associated with caloric overload, and that pharmacological inhibition of CaMKK2 reverses hepatic steatosis and regresses hepatic tumor growth. Furthermore, loss of CaMKK2 reduces expression of several inflammatory markers, indicating the importance of CaMKK2 in regulating the inflammatory response. To clarify the role of CaMKK2 in macrophages, we developed a myeloid-specific CaMKK2 knockout (CaMKK2MKO) and evaluated its response to chronic high-fat diet feeding. Resulting macrophage ablation of CaMKK2 conferred protection against the detrimental effects of caloric overload by improving peripheral insulin sensitivity, reducing hepatic steatosis and decreasing central adiposity. Additionally, RNA-Seq analysis from epidydimal white adipose tissue (eWAT) shows that CaMKK2MKO mice have a robust activation of fatty-acid metabolic programs and a concomitant reduction in pro-inflammatory signaling. Assessment of mitochondrial performance reveals that loss or inhibition of CaMKK2 confers a reprogramming of naïve macrophages to more efficiently metabolize fatty-acid substrates. These results are corroborated with b-oxidation assays that show macrophages devoid of CaMKK2 have a significantly improved capacity to utilize fatty-acids and retain elevated oxidation levels despite inflammatory stimuli. Based on these findings, we hypothesize that CaMKK2 functions as a metabolic sensor in macrophages to modulate the balance of fuel utilization between glycolytic and oxidative pathways, reprogramming the cell’s ability to respond to metabolic stimuli. I will test this hypothesis in Aim 1 by determining the role of CaMKK2 in the regulation of macrophage fuel preference and function. Building on this information, Aim 2 will focus on characterizing the mechanism(s) by which CaMKK2 reprograms macrophage metabolic capability by examining the downstream functions of Mitofusin-2 (Mfn2) on mitochondrial dynamics. We have developed the necessary tools to identify novel interactants and substrates of CaMKK2 in macrophages in the hopes of providing a mechanistic explanation to support the metabolic benefits associated with inhibition or loss of CaMKK2. Collectively, our findings highlight an unappreciated role of CaMKK2 as a driver of metabolic dysfunction and expose a new target for therapeutic intervention of metabolic syndrome.

项目摘要/摘要 肥胖症的流行是一种日益严重的危机，使患有肥胖症的人容易患新陈代谢的共病。 综合症包括高血压、2型糖尿病和肝病。在临床上，肥胖被定义为低度肥胖。 受巨噬细胞渗透和激活影响的炎症性疾病。解决这个心烦意乱 炎症反应可能是代谢综合征发生和发展的一种手段 绕过了。钙/钙调蛋白激酶级联反应的激活与代谢异常有关 过程和饮食诱导的肥胖的一个因素。我们鉴定了钙/钙调蛋白依赖蛋白 蛋白激酶2(CAMKK2)在巨噬细胞中高表达，并被钙离子和钙离子协同激活 长链脂肪酸，这两种信号在肥胖期间会升高。我们已经证明，缺乏CAMKK2的小鼠 对于通常与卡路里超负荷有关的疾病是难治的，而药物抑制 CAMKK2逆转肝脏脂肪变性，逆转肝脏肿瘤生长。此外，CAMKK2的损失减少 几种炎症标志物的表达，表明CAMKK2在调节炎症反应中的重要性 回应。为了阐明CAMKK2在巨噬细胞中的作用，我们开发了髓系特异性的CAMKK2基因敲除 (CaMKK2MKO)，并评估其对慢性高脂饮食喂养的反应。由此产生的巨噬细胞消融 CAMKK2通过改善外周胰岛素对卡路里超负荷的有害影响提供保护 敏感度，减少肝脏脂肪变性，减少中心性肥胖。此外，RNA-Seq分析来自 外膜白色脂肪组织(EWAT)显示CaMKK2MKO小鼠具有很强的脂肪酸激活能力 代谢程序和伴随而来的促炎信号的减少。线粒体的评估 性能显示，CAMKK2的丢失或抑制使幼稚的巨噬细胞重新编程为更多 高效代谢脂肪酸底物。这些结果得到了b-氧化分析的证实，表明 缺乏CAMKK2的巨噬细胞利用脂肪酸的能力显著提高，并保持升高的 尽管有炎症刺激，但仍有氧化水平。基于这些发现，我们假设CAMKK2功能 作为巨噬细胞的代谢感受器，调节糖酵解和氧化之间的燃料利用平衡 途径，重新编程细胞对代谢刺激的反应能力。我将在目标1中通过以下方式测试这一假设 确定CAMKK2在调节巨噬细胞燃料偏好和功能中的作用。以此为基础 信息，目标2将集中在描述CAMKK2重新编程巨噬细胞的机制(S) 通过检测丝裂原蛋白-2(Mfn2)在线粒体动力学中的下游功能来研究其代谢能力。 我们已经开发了必要的工具来鉴定巨噬细胞中CAMKK2的新的相互作用物和底物 希望提供一种机械的解释来支持与抑制相关的新陈代谢益处 或丢失CAMKK2。总而言之，我们的发现强调了CAMKK2作为新陈代谢驱动力的未被认识的作用 并为代谢综合征的治疗干预提供了新的靶点。