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: 10626764
• 负责人: Lan Zhou
• 金额: $ 22.51万
• 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 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10626764
• 关键词: Adult; Blood; Bone Marrow Transplantation; CC chemokine receptor 2; Cell Therapy; Cells; Chronic; Data; Development; Duchenne muscular dystrophy; Effector Cell; Embryo; Engraftment; Environment; Fetal Liver; Fibrosis; Future; Gene Expression; Genes; Genetic; Goals; Heterogeneity; Human; Infiltration; Inflammation; Inflammatory; Intramuscular; Knock-out; Knowledge; Label; Macrophage; Maps; Mediating; Mus; Muscle; Muscle Cells; Muscle function; Muscular Dystrophies; Myopathy; Normal tissue morphology; Pathogenicity; Pathology; Phenotype; Play; Publishing; Quantitative Reverse Transcriptase PCR; Respiratory Diaphragm; Role; Skeletal Muscle; Source; Surface; Testing; Therapeutic; Tissues; Vascular Endothelium; Yolk Sac; antagonist; behavioral study; chemokine receptor; gene therapy; improved; injured; 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; stem cell engraftment; 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.

项目概要 杜氏肌营养不良症 (DMD) 是最常见的遗传性肌肉疾病，具有致命性且无法治愈 观点。 DMD 及其小鼠模型 mdx5cv 的肌肉病理学特征为以慢性炎症为主 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，改善肌肉 炎症改善肌营养不良表型。它还可以改善局部组织环境，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具有异质性 不同的起源。根据组织的不同，它们可以是促炎、促纤维化或促再生的 环境和起源。虽然组织炎症 MP 来自血液单核细胞 (MO)，但组织 常驻 MP 可以源自血液 MO 和/或胚胎。小鼠外周血 MO 由两个组成 Ly6Chi 和 Ly6Clo 细胞亚群，以及人类的相应亚群。 Ly6Chi 细胞 (CCR2+/CX3CR1low) 是 炎症性 MO，通过 CC 趋化因子受体 2 (CCR2) 响应损伤而进入组织，然后 分化为炎性 MP。在受伤组织内，Ly6Chi MP 可以转变为 Ly6Clo MP。 Ly6Chi MOs 也可能有助于稳定状态下的组织驻留 MP。 Ly6Clo MO (CCR2-/CX3CR1hi) 巡逻 血管内皮表面，可通过趋化因子受体CX3CR1进入正常组织补充 常驻议员。胚胎来源的组织常驻 MP 也是 Ly6Clo，它们通过以下途径持续存在于成体组织中： 增殖性自我更新。我们的初步数据表明，MP 的 Ly6Chi 和 Ly6Clo 子集均在 mdx5cv 骨骼肌，并且 CCR2 对于 Ly6Chi 炎症 MO 的肌肉募集至关重要。 CCR2 的敲除会减少所有阶段的肌内 Ly6Chi MP，但只会减少早期的 Ly6Clo 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，支持肌内注射液的致病作用 Ly6Chi 议员。然而，在 mdx5cv/Ccr2-/- 小鼠中，有益效果在后期就消失了。 肌内 Ly6Clo MP 的扩增。仅针对 Ly6Chi 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 Ly6Clo MPs 也在 mdx5cv 隔膜中发挥致病作用 营养不良，来自不同来源的 Ly6Clo MP 可能有不同的贡献，并且针对单核细胞来源是 有治疗作用。我们将通过三个具体目标来检验我们的假设。目标 1 将研究起源 骨骼肌常驻 MPs 处于正常稳定状态。目标 2 将定义肌内 MP 的起源 mdx5cv 隔膜。目标 3 将确定肌内 MP 的效应器和调节功能 来自 mdx5cv 隔膜中的不同来源，并测试针对单核细胞来源的治疗潜力。 该项目将解决与肌内 MP 相关的关键问题，所获得的知识将 对于未来开发基于单核细胞/巨噬细胞的 DMD 新型疗法至关重要。