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 Duchenne肌肉营养不良（DMD）是最常见的遗传肌肉疾病，是致命的，没有治愈 观点。 DMD的肌肉病理及其小鼠模型MDX5CV具有主要的慢性炎症 巨噬细胞（MP）浸润。我们实验室和其他实验室的临床前研究表明，可以改善肌肉 炎症改善了肌营养不良的表型。它还改善了当地的组织环境以促进 肌肉再生以及基因和细胞植入。组织巨噬细胞在功能上是异质的 多样化的起源。它们可以是促炎，促纤维化或促启发性的，具体取决于组织 环境和起源。而组织炎性MPS是从血液单核细胞（MOS）衍生而来的 居民MP可以源自血液MOS和/或胚​​胎。鼠外围血液MOS由两个 子集，Ly6chi和Ly6clo细胞，在人类中具有相应的子集。 Ly6chi细胞（CCR2+/CX3CR1LOW）为 炎性MOS，该MOS因CC趋化因子受体2（CCR2）而响应损伤而进入组织，然后 分化为炎症MP。在受伤的组织中，LY6CHI MP可以切换到LY6CLO MPS。 ly6chi mos 也可能在稳态下有助于组织常驻MP。 ly6clo mos（ccr2-/cx3cr1hi）巡逻 血管内皮表面，可能通过趋化因子受体CX3CR1进入正常组织以补充 居民议员。胚胎衍生的组织驻留MP也是Ly6clo，它们通过 增生性自我更新。我们的初步数据表明，MPS的Ly6chi和Ly6clo子集均积累 MDX5CV骨骼肌，而CCR2对于Ly6CHI炎症性MOS的肌肉募集至关重要。 CCR2的敲除在所有阶段都会减少肌内LY6CHI MPS，但仅在早期降低Ly6clo MPS 阶段。早期肌内MPS的减少伴随着肌肉损伤的减少， 减少肌肉纤维化和改善的肌肉功能，这支持了肌内的致病作用 Ly6chi MPS。但是，在MDX5CV/CCR2 - / - 小鼠之后的MDX5CV/CCR2 - / - 肌内LY6CLO MPS的扩展。仅针对LY6CHI MP并不能提供持续的好处。我们 因此产生了我们的中心假设，即Ly6Clo MP在MDX5CV隔膜中也起致病作用 来自不同起源的营养不良，LY6CLO MP的贡献可能有所不同，靶向单核细胞起源为 治疗上有用。我们将通过三个具体目标检验我们的假设。 AIM 1将研究的起源 正常稳态处的骨骼肌常驻MP。 AIM 2将定义肌内MPS的起源 MDX5CV隔膜。 AIM 3将确定肌内MPS的效应子和调节功能 从MDX5CV隔膜中的不同起源，并测试靶向单核细胞起源的治疗潜力。 该项目将解决与肌内议员有关的关键问题，而获得的知识将是 对于DMD的新型单核细胞/巨噬细胞疗法的未来开发至关重要。