Pulmonary fibrosis is modulated by MCU-mediated macrophage apoptosis resistance

MCU介导的巨噬细胞凋亡抵抗调节肺纤维化

• 批准号: 10754498
• 负责人: A BRENT CARTER
• 金额: --
• 依托单位: BIRMINGHAM VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2023-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10754498
• 关键词: Alveolar Macrophages; Apoptosis; Apoptotic; Asbestos; Asbestosis; Attenuated; BCL-2 Protein; BCL2 gene; Binding Proteins; Bioenergetics; Biological; Bleomycin; Bone Marrow; Calcium; Carnitine Palmitoyltransferase I; Cell Survival; Cell physiology; Cells; Chimera organism; Chronic Disease; Cytosol; Data; Development; Disease Progression; Dominant-Negative Mutation; Enzymes; Exhibits; Fibrosis; Generations; Human; Immune response; In Vitro; Induction of Apoptosis; Link; Lipids; Lung; Lung diseases; Macrophage; Macrophage Activation; Mediating; Metabolic; Metabolism; Mitochondria; Molecular; Mus; Pathogenesis; Peroxisome Proliferator-Activated Receptors; Phenotype; Play; Process; Pulmonary Fibrosis; Reactive Oxygen Species; Resistance; Resolution; Role; Testing; Tissues; calcium uniporter; fatty acid oxidation; fibrogenesis; fibrotic lung; fighting; genetic approach; human subject; idiopathic pulmonary fibrosis; injury and repair; lung injury; lung repair; monocyte; mortality; organ injury; prevent; repaired; transcription factor

! In fibrotic disorders of the lung, including idiopathic pulmonary fibrosis (IPF), lung macrophages have a decisive role in fibrotic repair of injured lung. Macrophages play an integral role in the normal resolution of organ injury but also contribute to the pathogenesis of pulmonary fibrosis by initiating an immune response and by generating reactive oxygen species (ROS), particularly mitochondrial ROS (mtROS). Lung remodeling during pulmonary fibrosis is poorly understood; however, changes in mitochondrial bioenergetics in monocyte- derived macrophages are emerging as a critical determinant of fibrotic repair. The generation of mtROS is linked to calcium (Ca2+) influx into the mitochondria, which is regulated, in part, by the mitochondrial Ca2+ uniporter (MCU). Macrophages in chronic disease typically exhibit apoptosis resistance, and their prolonged survival is associated with disease progression. Metabolic reprogramming to fatty acid oxidation (FAO) is a key feature in macrophage activation. The relative efficiency of FAO is well suited to meet the metabolic requirements necessary for the repair of injured tissue. Our preliminary data show that lung macrophages from IPF subjects have increased expression of peroxisome proliferator-activated receptor coactivator-1 (PGC-1a), a transcription factor that leads to increased enzymatic capacity for FAO, carnitine palmitoyltransferase IA (CPT1A), the rate limiting mitochondrial lipid transporter, and mitochondrial Bcl-2 compared to normal subjects. MCU deficiency attenuates PGC-1a expression, and dominant-negative (DN)-MCU expression abrogates FAO. These findings are relevant because by generating reciprocal bone marrow chimeras using WT and MCU+/- mice, we found mice that received MCU+/- bone marrow were protected from bleomycin-induced pulmonary fibrosis. We hypothesize that MCU mediates pulmonary fibrosis by metabolic reprogramming of lung macrophages to induce apoptosis resistance. We will test this hypothesis with three aims. Aim 1 will test if MCU modulates macrophage metabolic reprogramming to FAO and if MCU is required for pulmonary fibrosis utilizing mice harboring expression of a dominant-negative (DN)-MCU in monocyte-derived macrophages. In Aim 2, we will test if MCU mediates apoptosis resistance by inducing metabolic reprogramming to FAO and enhancing expression of anti-apoptotic Bcl-2 proteins that bind to CPT1a using genetic approaches and in mice harboring expression of DN-MCU or a deletion of Bcl-2 in monocyte-derived macrophages. Aim 3 will provide human biological evidence of the importance of MCU in fibrosis development by determining if modulation of MCU in lung macrophages from IPF subjects regulates FAO and resistance to apoptosis. Understanding the role of MCU in lung macrophages may provide an important target for preventing or halting progression of fibrosis.

！在肺部纤维化疾病中，包括特发性肺纤维化（IPF），肺巨噬细胞具有 在受损肺纤维化修复中起决定性作用。巨噬细胞在正常分解过程中发挥着不可或缺的作用 器官损伤，而且还通过启动免疫反应和促进肺纤维化的发病机制 通过产生活性氧 (ROS)，特别是线粒体 ROS (mtROS)。肺重塑 对于肺纤维化期间的情况知之甚少；然而，单核细胞线粒体生物能的变化 衍生的巨噬细胞正在成为纤维化修复的关键决定因素。 mtROS的生成为 与钙 (Ca2+) 流入线粒体有关，这部分受到线粒体 Ca2+ 的调节 单端口（MCU）。慢性疾病中的巨噬细胞通常表现出细胞凋亡抗性，并且其长期存在 生存与疾病进展相关。脂肪酸氧化（FAO）的代谢重编程是关键 巨噬细胞激活的功能。粮农组织的相对效率非常适合满足新陈代谢 修复受损组织所必需的要求。我们的初步数据表明，肺巨噬细胞 IPF 受试者过氧化物酶体增殖物激活受体辅激活因子 1 (PGC-1a) 的表达增加， 一种转录因子，可提高 FAO 肉毒碱棕榈酰转移酶 IA 的酶能力 (CPT1A)，限速线粒体脂质转运蛋白，以及与正常受试者相比的线粒体 Bcl-2。 MCU 缺陷减弱 PGC-1a 表达，显性失活 (DN)-MCU 表达消除 粮农组织。这些发现是相关的，因为通过使用 WT 和 MCU+/- 小鼠，我们发现接受 MCU+/- 骨髓的小鼠免受博来霉素诱导的影响 肺纤维化。 我们假设 MCU 通过肺巨噬细胞的代谢重编程介导肺纤维化 诱导细胞凋亡抵抗。我们将通过三个目标来检验这个假设。 目标 1 将测试 MCU 是否调节巨噬细胞代谢重编程至 FAO，以及是否需要 MCU 利用在单核细胞来源中表达显性失活 (DN)-MCU 的小鼠进行肺纤维化 巨噬细胞。 在目标2中，我们将测试MCU是否通过诱导FAO代谢重编程来介导细胞凋亡抵抗 使用遗传方法增强与 CPT1a 结合的抗凋亡 Bcl-2 蛋白的表达 在单核细胞衍生的巨噬细胞中表达 DN-MCU 或 Bcl-2 缺失的小鼠。 目标 3 将提供人类生物学证据，证明 MCU 在纤维化发展中的重要性 确定 IPF 受试者肺巨噬细胞中 MCU 的调节是否可调节 FFA 和耐药性 细胞凋亡。了解 MCU 在肺巨噬细胞中的作用可能为预防提供重要目标 或阻止纤维化的进展。