Defining the Role of Type III Collagen in Neonatal Tendon Development and Healing

项目摘要 肌腱可以承受大的力量，由于高度对齐，致密的胶原蛋白基质。然而，其低 细胞结构和相对不能招募损伤后的修复细胞，以及对过度损伤的敏感性。 瘢痕形成，导致肌腱结构和机械功能的丧失。I型胶原蛋白（Col 1）是主要的 健康肌腱的胶原蛋白和III型胶原蛋白（Col 3）是一种次要成分， 损伤持续增加的Col 3有助于持续的纤维血管瘢痕形成和结构和功能 肌腱愈合缺陷。在围产期肌腱中，Col 3增加，类似于损伤状态，与对照组相比， 健康成熟的肌腱。与愈合反应不同，新生肌腱发育的过程产生了一个 结构和功能上上级肌腱具有高度排列的Col 1致密基质。此外，新生儿 与愈合成熟的肌腱相比，发育中的肌腱表现出更高的愈合效率和质量 肌腱了解Col 3在新生肌腱发育和愈合过程中的作用， 用组织工程技术提高我们再现肌腱发育能力并改善肌腱损伤 治疗因此，我们的总体目标是描述Col 3对发育和愈合的贡献。 通过调节基质性质和细胞活性在新生儿肌腱中发挥作用。具体来说，我们将测试 假设Col 3对早期新生儿发育至关重要，但对发育的调节作用较小 在以后的时间点，肌腱中的相对Col 3降低。我们还假设新生肌腱 增强对肌腱损伤的强大增殖反应的能力，从而产生Col 3密集愈合 有利于肌腱祖细胞迁移和分化的基质，最终存款对齐，Col 1原纤维 恢复肌腱结构和功能。为了测试这些假设，我们生成了一种新型的、可诱导的Col 3 缺陷型小鼠（即Col 3a 1F/F）的免疫抑制以暂时控制Col 3减少。本研究的目标是：目标1：定义 新生肌腱发育阶段Col 3调节功能的时间动力学， 目的2：定义Col 3在新生儿愈合阶段的调节功能。粘弹性力学 检测、透射电子显微镜、免疫组织化学、基因表达、蛋白质组学和EST 11 整合素分析将用于评估钢筋束的结构、机械和组成特性， 两个目标。从这项工作中收集的见解将与减少Col 3的各种条件相关 表达包括血管Ehlers Danlos综合征，衰老，吸烟和更年期，并将强调 用于增强肌腱损伤治疗的治疗靶点。拟议的工作将在一个世界- 类培训环境在宾夕法尼亚大学的麦凯骨科研究实验室。这 环境与专家赞助团队相结合，包括肌腱结构研究专家， 功能以及基质生物学，将完全支持完成这一建议，并促进发展成为一个 有能力的独立研究者，能够进行严格和可重复的临床相关工作。

Project Abstract Tendons can withstand large forces due to a highly aligned, dense collagen matrix. However, their low cellularity and relative inability to recruit reparative cells post-injury, as well as susceptibility to excessive scarring, results in loss of tendon structure and mechanical function. Type I collagen (Col1) is the primary collagen of healthy tendon and type III collagen (Col3) is a minor constituent that increases in response to injury. Persistently increased Col3 contributes to persistent fibrovascular scarring and structural and functional deficits in the healing tendon. In perinatal tendons, Col3 is increased, similar to the injured state, compared to healthy mature tendons. Unlike the healing response, the process of neonatal tendon development yields a structurally and functionally superior tendon with a highly aligned Col1-dense matrix. Moreover, neonatal developing tendon demonstrates improved efficiency and quality of healing compared to healing mature tendon. Understanding the role of Col3 in the developmental and healing processes of the neonatal tendon will increase our ability to recapitulate tendon development with tissue engineering and improve tendon injury treatment. Therefore, our overall objective is to delineate the contribution of Col3 to development and healing in the neonatal tendon through modulation of matrix properties and cellular activity. Specifically, we will test the hypothesis that Col3 is crucial for early neonatal development but contributes less to regulation of development at later time points as relative Col3 in the tendon decreases. We also hypothesize that the neonatal tendon has enhanced capacity for a robust proliferative response to tendon injury which creates a Col3-dense healing matrix favorable for tendon progenitor migration and differentiation to ultimately deposit aligned, Col1 fibrils which restore tendon structure and function. To test these hypotheses, we generated a novel, inducible Col3 deficient mouse (i.e. Col3a1F/F) to temporally control Col3 reduction. The study aims are: Aim 1: Define the temporal dynamics of the regulatory function(s) of Col3 during phases of neonatal tendon development and Aim 2: Define the regulatory function(s) of Col3 during phases of neonatal healing. Viscoelastic mechanical testing, transmission electron microscopy, immunohistochemistry, gene expression, proteomics, and 11 integrin analyses will be used to assess the structural, mechanical, and compositional properties of tendons in both aims. Insights gleaned from this work will be relevant to a variety of conditions that reduce Col3 expression including vascular Ehlers Danlos syndrome, aging, smoking and menopause and will highlight therapeutic targets for enhancing tendon injury treatment. The proposed work will be carried out in a world- class training environment at the University of Pennsylvania’s McKay Orthopaedic Research Laboratory. This environment combined with an expert sponsorship team, including experts in studies of tendon structure and function as well as matrix biology, will fully support completion of this proposal and facilitate development into a competent independent investigator capable of producing rigorous and reproducible clinically relevant work.