Fine-tuning of mitochondrial Complex I activity in CD8 cells

CD8 细胞中线粒体复合物 I 活性的微调

• 批准号: 10092947
• 负责人: Mercedes Rincon
• 金额: $ 19.45万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10092947
• 关键词: ATP Synthesis Pathway; Alphaproteobacteria; Attenuated; Bacteria; Bacterial Proteins; Binding; C-terminal; CD8-Positive T-Lymphocytes; CD8B1 gene; Cell Proliferation; Cells; Complex; Computer Analysis; Coupled; Cytochrome c Reductase; Development; Electron Transport; Electron Transport Complex III; Electrons; Energy-Generating Resources; Eukaryotic Cell; Evolution; Exons; FADH2; Feedback; Gene Duplication; Generations; Genes; Glucose; Glycolysis; Goals; Grant; Heart; Immune; Immune response; Immune system; Immunotherapy; Inner mitochondrial membrane; Integral Membrane Protein; Kidney; Lead; Liver; Mass Spectrum Analysis; Mediating; Membrane; Membrane Potentials; Memory; Metabolic; Metabolism; Methylation; Mitochondria; Modeling; Molecular Conformation; Molecular and Cellular Biology; Multienzyme Complexes; N-terminal; NADH; NADH dehydrogenase (ubiquinone); Names; Nonesterified Fatty Acids; Nucleotide Biosynthesis; Oxidative Phosphorylation; Oxides; Oxidoreductase; Pharmacology; Process; Production; Protein Family; Proteins; Reactive Oxygen Species; Reagent; Regulation; Respiration; Respiratory Chain; Rickettsia; STAT3 gene; Structure; System; Time; Tissues; Vertebrates; complex IV; cytokine; cytotoxic; fatty acid oxidation; heat-shock proteins 40; improved; influenza infection; inhibitor/antagonist; member; mitochondrial membrane; mitochondrial metabolism; novel; novel strategies; oligomycin sensitivity-conferring protein; respiratory; response; sensor; vaccine response

SUMMARY Metabolism is a key factor for CD8 T cell immune response. Mitochondria metabolism is essential for effector function of CD8 cells. Thus, strategies to enhance mitochondrial respiration could be used to improve efficacy of CD8 cell immune response. However, while there are a number of pharmacological reagents inhibiting different steps of the electron transport chain and/or synthesis mitochondrial ATP, enhancing mitochondrial activity is not easy. We have recently identified MCJ (Methylation-Controlled J protein, also called DnaJC15) as an endogenous negative regulator of Complex I and mitochondrial respiration. We have shown that loss of MCJ results in increased Complex I activity, MMP, mitochondrial respiration and ATP levels in CD8 cells. Increased mitochondrial respiration caused by loss of MCJ enhances cytokine secretion as well as cytotoxic activity. Thus, finding how MCJ interacts with Complex I and how it is regulated could lead to new strategies to disrupt this metabolic brake. The N-terminal region of MCJ (N-MCJ) has no homology to known eukaryotic proteins, but it retains specific sequence present only in bacterial proteins from different Alphaproteobacteria species. Interestingly, those bacterial proteins have an oxidoreductase activity, similarly to Complex I NADH dehydrogenase. N-MCJ interacts with NDUFv1, the subunit of Complex I that contains the NADH dehydrogenase activity to oxidize NADH to NAD+. Our recent computational analysis together with mass spectrometry suggest that N-MCJ can bind NAD+. We propose a model where MCJ acts as a dynamic negative regulator of Complex I with NAD+ as a sensor. When NAD+ levels produced by an active Complex I are elevated, NAD+ binds N-MCJ. Binding of NAD+ to N-MCJ then causes a structural change that makes N-MCJ accessible to interact with NDUFv1, and provide a negative feedback to Complex I to attenuate its activity and avoid overconsumption of limited metabolic substrates. We will investigate: 1) The binding of NAD+ to N-MCJ and its effect on N-MCJ conformational changes; 2) The dynamic interaction of N-MCJ with NDUFv1, its fine-tuning by NAD+ and the impact in mitochondrial respiration. Results from these studies could lead to the development of novel strategies and mechanisms to safely increase mitochondrial respiration in CD8 cells and enhance immune responses.

概括 代谢是 CD8 T 细胞免疫反应的关键因素。线粒体代谢对于 CD8细胞的效应功能。因此，增强线粒体呼吸的策略可用于改善 CD8细胞免疫反应的功效。然而，虽然有许多药理试剂 抑制电子传递链的不同步骤和/或合成线粒体 ATP，增强 线粒体活动并不容易。我们最近发现了 MCJ（甲基化控制的 J 蛋白，也 称为 DnaJC15）作为复合物 I 和线粒体呼吸的内源性负调节因子。我们有 研究表明，MCJ 的缺失会导致复合物 I 活性、MMP、线粒体​​呼吸和 ATP 水平增加 在CD8细胞中。 MCJ 缺失引起的线粒体呼吸增加也会增强细胞因子的分泌 作为细胞毒活性。因此，找到 MCJ 如何与复合物 I 相互作用以及它如何被调节可能会导致新的发现 破坏这种代谢刹车的策略。 MCJ 的 N 末端区域 (N-MCJ) 与已知的无同源性 真核蛋白质，但它保留了仅存在于不同细菌蛋白质中的特定序列 阿尔法变形菌属物种。有趣的是，这些细菌蛋白具有氧化还原酶活性，类似于 复合物 I NADH 脱氢酶。 N-MCJ 与 NDUFv1 相互作用，NDUFv1 是复合物 I 的亚基，包含 NADH 脱氢酶活性将 NADH 氧化为 NAD+。我们最近的计算分析以及 质谱分析表明 N-MCJ 可以结合 NAD+。我们提出了一个模型，其中 MCJ 充当动态 以 NAD+ 作为传感器的复合物 I 的负调节器。当活性物质产生 NAD+ 水平时 复合物 I 升高，NAD+ 结合 N-MCJ。 NAD+ 与 N-MCJ 的结合会导致结构变化 这使得 N-MCJ 可以与 NDUFv1 交互，并向复合体 I 提供负反馈 减弱其活性并避免过度消耗有限的代谢底物。我们将调查：1) NAD+与N-MCJ的结合及其对N-MCJ构象变化的影响； 2）动态交互 具有 NDUFv1 的 N-MCJ、NAD+ 对其进行微调以及对线粒体呼吸的影响。这些结果 研究可能会导致开发新的策略和机制来安全地增加线粒体 CD8 细胞的呼吸作用并增强免疫反应。