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.

项目总结/摘要 肥胖症的流行是一个日益严重的危机，它使受影响的个体容易患代谢紊乱的合并症。 综合征包括高血压、2型糖尿病和肝病。临床上，肥胖被定义为低度肥胖 受巨噬细胞浸润和活化影响的炎性疾病。解决这一困扰 炎症反应可能是代谢综合征发病和进展的一种手段， 规避。钙/钙调蛋白激酶级联的激活与异常代谢紊乱有关。 过程和饮食引起的肥胖的贡献者。我们鉴定了钙/钙调素依赖蛋白， 激酶激酶2（CaMKK 2）在巨噬细胞中高度表达，并被Ca 2+和Ca 2+协同激活。 长链脂肪酸，这两种信号在肥胖期间升高。我们已经证明缺乏CaMKK 2的小鼠 对通常与热量超负荷相关的疾病是难治的， CaMKK 2逆转肝脂肪变性并使肝肿瘤生长消退。此外，CaMKK 2的损失减少 几种炎症标志物的表达，表明CaMKK 2在调节炎症反应中的重要性。 反应为了阐明CaMKK 2在巨噬细胞中的作用，我们开发了一种骨髓特异性CaMKK 2敲除方法， （CaMKK 2 MKO），并评估其对慢性高脂饮食喂养的反应。导致巨噬细胞消融 CaMKK 2通过改善外周胰岛素分泌，保护机体免受热量超载的不利影响。 敏感性，减少肝脂肪变性和减少中心性肥胖。此外，来自 皮下白色脂肪组织（eWAT）显示CaMKK 2 MKO小鼠具有脂肪酸的稳健活化 代谢程序和伴随的促炎信号传导的减少。线粒体的评估 性能表明，CaMKK 2的损失或抑制赋予幼稚巨噬细胞重编程更多的细胞， 有效代谢脂肪酸底物。这些结果得到了b-氧化测定的证实，表明 缺乏CaMKK 2的巨噬细胞具有显著提高的利用脂肪酸的能力，并保持升高的 氧化水平，尽管炎症刺激。基于这些发现，我们假设CaMKK 2的功能 作为巨噬细胞中的代谢传感器，调节糖酵解和氧化之间的燃料利用平衡 通过改变细胞的代谢途径，重新编程细胞对代谢刺激做出反应的能力。我将在目标1中检验这一假设， 确定CaMKK 2在巨噬细胞燃料偏好和功能调节中的作用。在此基础上 信息，目标2将集中于表征CaMKK 2重编程巨噬细胞的机制 通过检查线粒体融合蛋白-2（Mfn 2）对线粒体动力学的下游功能来评估代谢能力。 我们已经开发了必要的工具来识别巨噬细胞中CaMKK 2的新型相互作用物和底物 希望能提供一个机制性的解释来支持与抑制相关的代谢益处， 或CaMKK 2的丢失。总的来说，我们的研究结果强调了CaMKK 2作为代谢动力的未被重视的作用。 为代谢综合征的治疗干预提供了新的靶点。