Injury Response in Normal and EDS Tendons: Regulatory Roles of Collagen V

正常肌腱和 EDS 肌腱的损伤反应：V 型胶原蛋白的调节作用

• 批准号: 8669381
• 负责人: DAVID E BIRK
• 金额: $ 35.29万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8669381
• 关键词: Affect; Architecture; Area; Chronic; Collagen; Collagen Fibril; Connective Tissue; Coupled; Data; Data Analyses; Defect; Deposition; Development; Ehlers-Danlos Syndrome; Fatigue; Fiber; Flexor; Foundations; Future; Gait abnormality; Goals; Healed; Impairment; Individual; Inflammatory; Injury; Joint Dislocation; Joint Instability; Joint Laxity; Ligaments; Link; Measures; Mechanics; Mediating; Minor; Modality; Modeling; Molecular; Mus; Mutation; Performance; Phase; Phenotype; Property; Role; Skin; Structure; Tendinopathy; Tendon Injuries; Tendon structure; Testing; Therapeutic Intervention; Time; Tissue Engineering; Up-Regulation; Work; Wound Healing; anterior cruciate ligament rupture; base; comparative; healing; heritable connective tissue disorder; innovation; mouse model; public health relevance; repaired; response; response to injury; therapy design; wound

DESCRIPTION (provided by applicant): The overall goal of this proposal is to define the regulatory roles of collagen V in the injury response in normal and classic Ehlers-Danlos syndrome (EDS) tendons. Collagen V is a quantitatively minor component of collagen fibrils, yet modulation of its expression has dramatic phenotypic effects, indicating critical regulatory roles. EDS is a heritable connective tissue disorder with generalized connective tissue fragility and the classic form is characterized by hyperextensible skin, joint laxity and instability, as well as abnormal wound healing. Classic EDS is defined by collagen V mutations with haploinsufficiency for COL5A1 present in ~67% of affected individuals. Collagen V also has been linked to: Achilles tendinopathy, ACL rupture, as well as injury and performance deficiencies. In addition, upregulation of collagen V is observed in the injury response in tendons and ligaments. Our established haploinsufficent collagen V EDS mouse model will be used for the proposed studies. However, this model has limitations due to chronic effects resulting from lack of collagen V throughout development and maturation that are then superimposed on the changes associated with the injury response. Therefore, this proposal incorporates our inducible collagen V-null and heterozygous models that allow for temporal targeting of the modulation of collagen V expression. For the first time, directly studying the critical regulatory roles of collagen V during specific phases of the injury response will be possible. Using the haploinsufficient collagen V EDS model, we have demonstrated reduced fibril number, abnormal fibril structure, decreased cross sectional area, and a reduction in the stiffness of the flexor digitorum longus tendon consistent with the hypermobile EDS phenotype. Our recent work using a conditional null model demonstrated severe structural alterations at the fibril, fiber and tendon level associated with severely compromised mechanical function, joint dislocations and gait abnormalities. The general hypothesis tested in this proposal is that the tendon response to injury is modulated by collagen V mediated mechanism(s). The aims are to: (Aim 1) Define the altered regulatory function(s) of collagen V in the abnormal tendon injury response in classic EDS~ (Aim 2) Elucidate the mechanistic regulatory role(s) of collagen V in the repair response to tendon injury in a normal matrix~ and (Aim 3) Compare the effect of modulation of collagen V expression on the injury response in normal and in diseased/abnormal tendons. Our innovative approach with both conventional and inducible mouse models will systematically analyze the regulatory roles of collagen V on repair of tendon injuries. This approach will be coupled with sophisticated and innovative measures of mechanical and organizational properties, together with compositional profiles, to derive a mechanistic understanding of the injury responses. These studies will define the specific temporal regulatory roles of collagen V in the re- establishment of tendon structure and function in response to injury. In addition, the data will provide a critical foundation for developing therapeutic interventions to enhance the abnormal wound healing in EDS.

描述（由申请人提供）：该提案的总体目标是确定胶原蛋白 V 在正常和经典埃勒斯-当洛斯综合征 (EDS) 肌腱损伤反应中的调节作用。 V 型胶原蛋白在数量上是胶原原纤维的次要成分，但其​​表达的调节具有显着的表型效应，表明具有关键的调节作用。 EDS 是一种遗传性结缔组织疾病，具有全身性结缔组织脆性，其典型特征是皮肤过度伸展、关节松弛和不稳定以及伤口愈合异常。 经典 EDS 的定义是胶原蛋白 V 突变，约 67% 的受影响个体中存在 COL5A1 单倍体不足。 V 型胶原蛋白还与以下因素有关：跟腱病、ACL 断裂以及损伤和表现缺陷。此外，在肌腱和韧带的损伤反应中观察到胶原蛋白 V 的上调。我们建立的单倍体胶原蛋白不足 EDS 小鼠模型将用于拟议的研究。然而，该模型存在局限性，因为在整个发育和成熟过程中缺乏胶原蛋白 V 会产生慢性影响，然后叠加在与损伤反应相关的变化上。因此，该提案结合了我们的诱导型胶原蛋白 V 无效和杂合模型，允许对胶原蛋白 V 表达的调节进行时间靶向。首次有可能直接研究 V 型胶原蛋白在损伤反应特定阶段的关键调节作用。使用单倍体胶原蛋白不足的 V EDS 模型，我们证明了原纤维数量减少、原纤维结构异常、横截面积减小以及指长屈肌腱硬度降低，这与过度活动的 EDS 表型一致。我们最近使用条件零模型的工作证明了原纤维、纤维和肌腱水平的严重结构改变与机械功能严重受损、关节脱位和步态异常相关。本提案测试的一般假设是肌腱对损伤的反应是由胶原蛋白 V 介导的机制调节的。目标是：（目标 1）定义经典 EDS 中异常肌腱损伤反应中胶原蛋白 V 调节功能的改变~（目标 2）阐明胶原蛋白 V 在正常基质中肌腱损伤修复反应中的机制调节作用~以及（目标 3）比较胶原蛋白 V 表达调节对正常肌腱和患病/异常肌腱损伤反应的影响。我们使用传统和诱导小鼠模型的创新方法将系统地分析胶原蛋白 V 对肌腱损伤修复的调节作用。这种方法将与机械和组织特性的复杂和创新测量以及成分概况相结合，以获得对损伤反应的机械理解。这些研究将确定胶原蛋白 V 在重建肌腱结构和功能以应对损伤时的具体时间调节作用。此外，这些数据将为开发治疗干预措施以增强 EDS 异常伤口愈合提供重要基础。