Regulation of Morphogenesis and Extracellular Matrix Assembly at the Myotendinous Junction

肌腱连接处形态发生和细胞外基质组装的调节

• 批准号: 9217590
• 负责人: Thomas F Schilling
• 金额: $ 33.99万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-01 至 2021-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9217590
• 关键词: Address; Adhesions; Architecture; Back; Binding Proteins; Biological Assay; Cells; Connective Tissue; Data; Defect; Development; Disease; Elasticity; Embryo; Exercise; Exposure to; Extracellular Matrix; Extracellular Matrix Proteins; F-Actin; Feeds; Fibroblasts; Filopodia; Fluorescence; Gene Expression; Genetic; Goals; Head; Human; Image; In Vitro; Injury; Integrins; Ligaments; Ligands; Limb structure; Maintenance; Membrane Glycoproteins; Mesoderm; Methods; Microscopy; Modeling; Mohawk; Monitor; Morphogenesis; Muscle; Muscle Contraction; Musculoskeletal System; Mutant Strains Mice; Neural Crest; Pharmacological Treatment; Pharmacology; Physiological; Play; Principal Investigator; Process; Production; Regulation; Research; Role; Signal Transduction; Site; Spatial Distribution; Specific qualifier value; Stem cells; Structure; Tendinopathy; Tendon Injuries; Tendon structure; Testing; Thrombospondins; Transforming Growth Factor beta; Transgenic Organisms; Ursidae Family; Zebrafish; bone; cell fate specification; feeding; genetic manipulation; human stem cells; in vivo imaging; inhibitor/antagonist; injury and repair; loss of function; mechanical force; mechanical load; mutant; myogenesis; novel; overexpression; progenitor; programs; public health relevance; repaired; response; scleraxis; skeletogenesis; stem; tendon development; transcription factor

 DESCRIPTION (provided by applicant): The formation of myotendinous junctions (MTJs) is a fundamental component of a functional musculoskeletal system. Muscles interact with tendons at their attachment sites, causing a reorganization of the extracellular matrix (ECM) into connective tissue structures that can bear the large forces exerted by muscle contraction. The transcription factors Scleraxis (Scx) and Mohawk (Mkx), as well as the membrane glycoprotein Tenomodulin (Tnmd), specify early tendon progenitors and regulate ECM production, and we recently discovered an ECM protein and Integrin (Itg) ligand called Thrombospondin-4b (Tsp4b) in zebrafish that is regulated by Scx and required for muscle attachment. How tendon progenitors reach sites of muscle attachment and influence ECM assembly and muscle adhesion at the MTJ remains unclear. The current proposal addresses these issues using the advantages of the zebrafish for in vivo imaging and genetic manipulation. The long-term goal of the proposed research is to understand the spatial dynamics of ECM assembly and cell fate specification in tendons and ligaments. Two primary hypotheses guide the research: 1) Mkx and Tnmd interact with Scx to control tenocyte morphogenesis and ECM assembly at MTJs, and 2) Itg and Tgfb signaling in response to mechanical load regulates Scx, Mkx and Tnmd expression during the formation of MTJs. Aim 1 is to visualize tendon progenitors in living wild-type, Mkx and Tnmd mutant embryos. Aim 2 is to study roles for Itg and Tgfb signaling in regulation of Scx, Mkx and Tnmd expression. Aim 3 is to study the roles of Itg and Tgfb signaling in response to mechanical load. Each aim combines novel genetic manipulation, fluorescence dynamics imaging and quantitative methods for physiological stimulation of muscles to get at the mechanisms of ECM assembly at these specialized connective tissue structures.

 描述（由申请人提供）：肌腱连接（MTJ）的形成是功能性肌肉骨骼系统的基本组成部分。肌肉在其附着部位与肌腱相互作用，导致细胞外基质（ECM）重组为结缔组织结构，可以承受肌肉收缩所施加的巨大力量。转录因子 Scleraxis (Scx) 和 Mohawk (Mkx) 以及膜糖蛋白 Tenomodulin (Tnmd) 指定早期肌腱祖细胞并调节 ECM 产生，我们最近在斑马鱼中发现了一种称为 Thrombospondin-4b (Tsp4b) 的 ECM 蛋白和整合素 (Itg) 配体，它受 Scx 调节且是肌肉所需的 依恋。肌腱祖细胞如何到达肌肉附着部位并影响 ECM 组装和 MTJ 处的肌肉粘附仍不清楚。当前的提案利用斑马鱼在体内成像和基因操作方面的优势来解决这些问题。该研究的长期目标是了解肌腱和韧带中 ECM 组装和细胞命运规范的空间动力学。两个主要假设指导了这项研究：1) Mkx 和 Tnmd 与 Scx 相互作用，控制 MTJ 处的肌腱细胞形态发生和 ECM 组装，2) 响应机械负荷的 Itg 和 Tgfb 信号传导在 MTJ 形成过程中调节 Scx、Mkx 和 Tnmd 的表达。目标 1 是观察活体野生型、Mkx 和 Tnmd 突变胚胎中的肌腱祖细胞。目标 2 是研究 Itg 和 Tgfb 信号在 Scx、Mkx 和 Tnmd 表达调节中的作用。目标 3 是研究 Itg 和 Tgfb 信号在机械负载响应中的作用。每个目标都结合了新颖的基因操作、荧光动力学成像和肌肉生理刺激的定量方法，以了解这些特殊结缔组织结构中 ECM 组装的机制。