Tendon Tissue Engineering Informed by Lysyl Oxidase Regulation of Embryonic Tendon Mechanical Properties

项目摘要 肌肉骨骼损伤是美国残疾和医疗费用的主要原因。约 一半的损伤涉及肌腱和韧带。终身功能障碍、疼痛和再发的风险增加 由于愈合不良而导致的损伤促使我们的长期目标是从干细胞再生新肌腱， 恢复功能和生活质量。典型的基于干细胞的方法旨在促进细胞外基质的量。 基质（ECM）含量，假设ECM量与机械性能相关。然而，在这方面， 这些方法尚未实现功能性肌腱。这让我们不禁要问肌腱是如何发育的 自然在胚胎中，以告知间充质干细胞（MSC）为基础的肌腱再生方法。 我们最近在鸡胚中的研究表明，赖氨酰氧化酶（LOX）介导的交联 与肌腱发育过程中的机械性能密切相关， 降低了交联和弹性模量，尽管基质含量持续增加。此外，LOX 活动似乎是由胚胎踢（机械负荷）调节的。基于这些令人兴奋的数据，我们 假设LOX是发育中肌腱机械性能的关键调节因子， 对LOX活性的知情操纵可以促进MSC的功能性肌腱再生。的假设 将测试以下三个具体目标：1）确定LOX表达模式和作用， 胚胎肌腱力学性能的发展; 2）阐明机械负荷如何调节LOX 在胚胎肌腱发育过程中; 3）开发方法来增强工程MSC-构建体 通过LOX介导的交联的机械性能。 建议的工作是创新的，因为我们的方法侧重于恢复ECM质量，而不是 再生肌腱基质的量，旨在为这种方法提供胚胎发育的信息。我们 一种新的策略将鸡胚模型与组织工程和生物反应器加载系统相结合， 研究LOX和机械负荷在功能性肌腱发育中相互作用。我们的长期目标是 设计开发灵感LOX靶向疗法，利用MSC改善肌腱力学 特性.

PROJECT SUMMARY Musculoskeletal injuries are a leading cause of disability and medical costs in the United States. Approximately half of these injuries involve tendons and ligaments. The lifelong dysfunction, pain, and increased risk of re- injury due to poor healing have motivated our long-term goal to regenerate new tendon from stem cells to restore function and quality of life. Typical stem cell-based approaches aim to promote quantity of extracellular matrix (ECM) content, with the assumption that ECM quantity correlates with mechanical properties. However, these approaches have yet to achieve functional tendons. This has led us to ask how tendon develops naturally in the embryo to inform a mesenchymal stem cell (MSC)-based tendon regeneration approach. Our studies in the chick embryo recently showed that lysyl oxidase (LOX)-mediated crosslinking correlates strongly with mechanical properties during tendon development, and that inhibition of LOX activity reduces crosslinking and elastic modulus despite continued increases in matrix content. Furthermore, LOX activity appears to be regulated by embryonic kicking (mechanical loading). Based on these exciting data, we hypothesize LOX is a critical regulator of developing tendon mechanical properties, and that developmentally informed manipulation of LOX activity can promote functional tendon regeneration with MSC. The hypothesis will be tested with the following three specific aims: 1) determine LOX expression patterns and role in embryonic tendon mechanical property development; 2) elucidate how mechanical loading regulates LOX during embryonic tendon development; 3) develop approaches to enhance engineered MSC-construct mechanical properties via LOX-mediated crosslinking. The proposed work is innovative because our approach focuses on restoring ECM quality, rather than quantity, of the regenerating tendon matrix, and aims to inform this approach with embryonic development. Our novel strategy combines the chick embryo model with tissue engineering and bioreactor loading systems to investigate LOX and mechanical loading interactions in functional tendon development. Our long-term goal is to design developmentally inspired LOX-targeted therapies utilizing MSC to improve tendon mechanical properties.