Modulating Cell-fate to Promote Regenerative Tendon Healing

调节细胞命运促进肌腱再生愈合

• 批准号: 10447794
• 负责人: Alayna Loiselle
• 金额: $ 38.69万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-08 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10447794
• 关键词: Acute; Affect; Apoptosis; Articular Range of Motion; Biomechanics; Cell Lineage; Cells; Chronic; Cicatrix; Clinical; Coculture Techniques; Collagen Type I; Communication; Data; Deposition; Environment; Exhibits; Extracellular Matrix; Feedback; Fibroblasts; Fibrosis; Flexor; Gene Expression Profile; Heterogeneity; Immunophenotyping; Impaired healing; Impairment; Inflammation; Injury; Mediating; Molecular Profiling; Mus; Myofibroblast; NF-kappa B; Pharmacology; Phase; Phenotype; Play; Population; Production; Property; Reporter; Role; S100A4 gene; Signal Transduction; Site; System; Tendon Injuries; Tendon structure; Testing; Time; Tissue Sample; Tissues; Work; antagonist; healing; improved; injury and repair; macrophage; migration; mouse model; novel; p65; paracrine; periostin; recruit; regenerative; repaired; restoration; scleraxis; single-cell RNA sequencing; therapeutic target; time use; tissue repair; translational potential

Tendon injuries heal in a fibrotic manner via chronic deposition of excessive, disorganized extracellular matrix. Myofibroblasts are a critical driver of fibrosis in many tissues, and emerging evidence demonstrates myofibroblast heterogeneity. That is, myofibroblasts with unique molecular profiles that correspond to changes in myofibroblast function. Importantly, the fibroblast lineage from which myofibroblasts are derived also plays a major role in dictating myofibroblast function. However, very little is known about myofibroblast dynamics during fibrotic tendon healing, including their fibroblast/tenocyte-lineage, how their functions change over time, what the molecular profiles of these different myofibroblast subtypes are, and how myofibroblasts interact with other cells, such as macrophages, to mediate healing and fibrosis. We have identified Scleraxis-lineage and S100a4-lineage cells as the predominant myofibroblast precursor populations during tendon healing. Interestingly, depletion of S100a4-cells impairs early tendon healing, while Scx-cell depletion improves late tendon healing suggesting these cells may give rise to functionally distinct myofibroblast populations. In addition, our preliminary data identifies macrophages as a critical driver of the tenocyte-myofibroblast transition, and we observed prolonged macrophage presence during late healing, concomitant with NFB- mediated pro-survival signaling in myofibroblasts. These data are consistent with a pro-fibrotic feedback loop between macrophages and myofibroblasts to sustain fibrosis in many tissues. Thus, in the present study we will use a murine model of acute tendon injury and repair to rigorously define tenocyte lineage-specific contributions to myofibroblast fate and define myofibroblast heterogeneity during healing. We will test the central hypothesis that inhibiting macrophage-mediated myofibroblast differentiation and NF-B-mediated survival of lineage-specific myofibroblasts promotes regenerative tendon healing. We will test this hypothesis through the following specific aims: Aim 1: Define the temporal and tenocyte lineage-dependent immunophenotype of myofibroblasts during fibrotic tendon healing. Aim 2: Establish the requirement for extrinsic macrophages in fibrotic healing via modulation of the tenocyte-myofibroblast transition and test the translational potential of inhibiting macrophage recruitment. Aim 3: Demonstrate that disrupting myofibroblast survival or macrophage persistence inhibits sustained fibrosis and promotes regenerative tendon healing. Successful completion of these studies will establish myofibroblast lineage, molecular profile and activation mechanisms over time during fibrotic healing and define disruption of persistent myofibroblasts and macrophages as a novel means to improve tendon healing.

肌腱损伤通过过度的、无序的细胞外基质的慢性沉积以纤维化的方式愈合。 肌成纤维细胞是许多组织纤维化的关键驱动因素，新的证据表明， 肌成纤维细胞异质性也就是说，肌成纤维细胞具有独特的分子特征， 肌成纤维细胞功能。重要的是，肌成纤维细胞来源的成纤维细胞谱系也起着重要的作用。 在支配肌成纤维细胞功能中起主要作用。然而，对肌成纤维细胞动力学知之甚少 在纤维化肌腱愈合期间，包括它们的成纤维细胞/腱细胞谱系，它们的功能如何随时间变化， 这些不同肌成纤维细胞亚型的分子特征是什么，以及肌成纤维细胞如何与 其他细胞，如巨噬细胞，介导愈合和纤维化。我们已经确定了巩膜细胞系， S100 a4系细胞作为肌腱愈合过程中的主要肌成纤维细胞前体群体。 有趣的是，S100 a4细胞的耗竭损害早期肌腱愈合，而Scx细胞耗竭改善晚期肌腱愈合。 肌腱愈合表明这些细胞可能产生功能不同的肌成纤维细胞群。在 此外，我们的初步数据表明，巨噬细胞是肌腱细胞-肌成纤维细胞 过渡，我们观察到在晚期愈合过程中延长的巨噬细胞存在，伴随着NF κ B B- 在肌成纤维细胞中介导促存活信号传导。这些数据与促纤维化反馈回路一致 巨噬细胞和肌成纤维细胞之间的相互作用以维持许多组织中的纤维化。因此，在本研究中， 将使用急性肌腱损伤和修复的小鼠模型来严格定义肌腱细胞谱系特异性 肌成纤维细胞的命运和定义愈合过程中的肌成纤维细胞异质性的贡献。我们将测试 抑制巨噬细胞介导的肌成纤维细胞分化和NF-κ B介导的 谱系特异性肌成纤维细胞的存活促进再生肌腱愈合。我们将检验这一假设 通过以下具体目标：目标1：定义时间和肌腱细胞谱系依赖 纤维化肌腱愈合过程中肌成纤维细胞免疫表型目标2：确定以下要求 外源性巨噬细胞通过调节腱细胞-肌成纤维细胞转变在纤维化愈合中的作用，并测试 抑制巨噬细胞募集的翻译潜力。目的3：证明破坏肌成纤维细胞 存活或巨噬细胞持续抑制持续纤维化并促进再生肌腱愈合。 这些研究的成功完成将建立肌成纤维细胞谱系、分子谱和活化 纤维化愈合期间随时间推移的机制，并定义持久性肌成纤维细胞的破坏， 巨噬细胞作为一种新的手段，以改善肌腱愈合。