Origins and Functions of Intramuscular Macrophages in Duchenne Muscular Dystrophy

杜氏肌营养不良症肌内巨噬细胞的起源和功能

• 批准号: 9817015
• 负责人: Lan Zhou
• 金额: $ 37.24万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-05 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9817015
• 关键词: Address; Adult; Blood; Bone Marrow Transplantation; CC chemokine receptor 2; Cell Therapy; Cells; Chronic; Data; Development; Duchenne muscular dystrophy; Effector Cell; Embryo; Engraftment; Environment; Expression Profiling; Fetal Liver; Fibrosis; Future; Gene Expression; Genes; Genetic; Goals; Heterogeneity; Human; Infiltration; Inflammation; Inflammatory; Intramuscular; Knock-out; Knowledge; Label; Mediating; Mus; Muscle; Muscle Cells; Muscle function; Muscular Dystrophies; Myopathy; Normal tissue morphology; Pathogenicity; Pathology; Phenotype; Play; Publishing; Respiratory Diaphragm; Reverse Transcriptase Polymerase Chain Reaction; Role; Skeletal Muscle; Source; Stem cells; Surface; Testing; Therapeutic; Tissues; Vascular Endothelium; Yolk Sac; base; behavioral study; chemokine receptor; gene therapy; improved; injured; macrophage; monocyte; mouse model; muscle regeneration; muscular dystrophy mouse model; novel; peripheral blood; preclinical study; recruit; regenerative; response to injury; self-renewal; single-cell RNA sequencing; therapeutic evaluation

Project Summary Duchenne muscular dystrophy (DMD), the most common genetic muscle disease, is lethal with no cure at this point. Muscle pathology of DMD and its mouse model mdx5cv features chronic inflammation with predominant macrophage (MP) infiltration. Preclinical studies by our lab and others demonstrate that ameliorating muscle inflammation improves muscular dystrophy phenotype. It also improves local tissue environment to promote muscle regeneration and gene and cell engraftment. Tissue macrophages are functionally heterogeneous with diverse origins. They can be pro-inflammatory, pro-fibrotic, or pro-regenerative depending on the tissue environment and origins. While tissue inflammatory MPs are derived from blood monocytes (MOs), tissue resident MPs can originate from blood MOs and/or embryo. Murine peripheral blood MOs consist of two subsets, Ly6Chi and Ly6Clo cells, with corresponding subsets in humans. Ly6Chi cells (CCR2+/CX3CR1low) are inflammatory MOs, which enter tissues in response to injury via CC chemokine receptor 2 (CCR2) and then differentiate into inflammatory MPs. Within injured tissues, Ly6Chi MPs can switch into Ly6Clo MPs. Ly6Chi MOs may also contribute to tissue resident MPs at the steady state. Ly6Clo MOs (CCR2-/CX3CR1hi) patrol the vascular endothelial surface and may enter normal tissue via chemokine receptor CX3CR1 to replenish resident MPs. Embryo-derived tissue resident MPs are also Ly6Clo, and they persist into adult tissues through proliferative self-renewal. Our preliminary data show that both Ly6Chi and Ly6Clo subsets of MPs accumulate in mdx5cv skeletal muscle, and that CCR2 is essential to the muscle recruitment of Ly6Chi inflammatory MOs. Knockout of CCR2 diminishes intramuscular Ly6Chi MPs at all stages, but it only reduces Ly6Clo MPs at early stages. The reduction of intramuscular MPs at the early stages is accompanied by decreased muscle damage, reduced muscle fibrosis, and improved muscle function, which supports a pathogenic role for the intramuscular Ly6Chi MPs. However, the beneficial effects are lost at the late stage in the mdx5cv/Ccr2-/- mice after the expansion of intramuscular Ly6Clo MPs. Targeting Ly6Chi MP alone does not provide sustained benefits. We thus generate our central hypothesis that Ly6Clo MPs also play a pathogenic role in the mdx5cv diaphragm dystrophy, Ly6Clo MPs from different origins may contribute differently, and targeting the monocytic origins is therapeutically useful. We will test our hypothesis by three Specific Aims. Aim 1 will study the origins of skeletal muscle resident MPs at the normal steady state. Aim 2 will define the origins of intramuscular MPs in the mdx5cv diaphragm. Aim 3 will determine the effector and regulatory functions of intramuscular MPs derived from different origins in the mdx5cv diaphragm, and test the therapeutic potential of targeting monocytic origins. This project will address the key questions related to the intramuscular MPs, and the knowledge gained will be critical to the future development of novel monocyte/macrophage-based therapies for DMD.

项目摘要 杜氏肌营养不良症（DMD），最常见的遗传性肌肉疾病，是致命的，没有治愈，在这个 点DMD及其小鼠模型mdx 5cv的肌肉病理学特征为慢性炎症， 巨噬细胞（MP）浸润。我们实验室和其他人的临床前研究表明，改善肌肉 炎症改善肌营养不良表型。它还改善了局部组织环境， 肌肉再生以及基因和细胞移植。组织巨噬细胞在功能上是异质的， 不同的起源。它们可以是促炎、促纤维化或促再生的，这取决于组织 环境和起源。虽然组织炎性MP来源于血液单核细胞（MO）， 常驻MP可以来源于血液MO和/或胚胎。小鼠外周血MO由两个 亚群，Ly 6Chi和Ly 6Clo细胞，以及人类中相应的亚群。Ly 6Chi细胞（CCR 2 +/CX 3CR 1低）是 炎性MO，其通过CC趋化因子受体2（CCR 2）响应于损伤进入组织，然后 分化成炎性MP。在受伤的组织中，Ly 6Chi MP可以转换为Ly 6Clo MP。Ly6Chi MOs 也可能有助于稳态下的组织驻留MP。Ly 6Clo MO（CCR 2-/CX 3CR 1hi）巡逻 血管内皮表面，并可通过趋化因子受体CX 3CR 1进入正常组织， 常驻议员胚胎来源的组织驻留MP也是Ly 6Clo，并且它们通过细胞周期持续进入成体组织。 增殖性自我更新我们的初步数据显示，MP的Ly 6Chi和Ly 6Clo亚群在细胞中积累。 mdx 5cv骨骼肌，并且CCR 2对于Ly 6Chi炎性MO的肌肉募集是必需的。 CCR 2的敲除在所有阶段减少肌内Ly 6Chi MP，但它仅在早期阶段减少Ly 6Clo MP。 阶段早期肌内MP的减少伴随着肌肉损伤的减少， 减少肌肉纤维化，改善肌肉功能，这支持肌内 Ly6Chi MP。然而，在mdx 5cv/Ccr 2-/-小鼠中，在给予Ccr 2后的晚期， 肌内Ly 6Clo MP的扩增。单独靶向Ly 6Chi MP并不能提供持续的益处。我们 因此产生了我们的中心假设，即Ly 6Clo MP也在mdx 5cv隔膜中起致病作用 对于营养不良，来自不同来源的Ly 6Clo MP可能有不同的贡献，并且靶向单核细胞来源是 治疗上有用。我们将通过三个具体目标来检验我们的假设。目标1将研究 骨骼肌驻留MP处于正常稳态。目的2将定义肌内MP的起源， mdx 5cv隔膜。目的3将确定肌内MP的效应和调节功能， 从不同来源的MDX 5CV隔膜，并测试靶向单核细胞来源的治疗潜力。 本项目将解决与肌内MP相关的关键问题，所获得的知识将是 这对DMD的新型单核细胞/巨噬细胞疗法的未来发展至关重要。