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

项目总结 在美国，肌肉骨骼损伤是导致残疾和医疗费用的主要原因。大致 这些损伤中有一半涉及肌腱和韧带。终生功能障碍、疼痛和复发风险增加 由于愈合不良造成的损伤促使我们的长期目标是从干细胞再生新的肌腱 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的数量 基质(ECM)含量，假设ECM数量与机械性能相关。然而， 这些方法还没有达到功能性肌腱。这让我们不禁要问肌腱是如何发育的 在胚胎中自然告知以间充质干细胞(MSC)为主的肌腱再生方式。 我们最近在鸡胚胎上的研究表明，赖氨酰氧化酶(LOX)介导的交联剂 在肌腱发育过程中，LOX活性的抑制与肌腱的力学性能密切相关 尽管基质含量持续增加，但降低了交联度和弹性模数。此外，LOX 活动似乎受胚胎踢(机械负荷)的调节。基于这些令人兴奋的数据，我们 假设LOX是肌腱力学性能发育的关键调节器，而且在发育过程中 知情操纵LOX活性可促进MSC的功能性肌腱再生。假说 将在以下三个具体目标下进行测试：1)确定LOX表达模式和在 胚胎肌腱力学性能发育；2)阐明机械负荷如何调节LOX 在胚胎肌腱发育过程中；3)开发增强工程化MSC构建的方法 通过LOX介导的交联剂的机械性能。 拟议的工作是创新的，因为我们的方法侧重于恢复ECM质量，而不是 再生肌腱基质的数量，目的是用胚胎发育来指导这一方法。我们的 将鸡胚胎模型与组织工程和生物反应器加载系统相结合的新策略 研究LOX和机械负荷在功能性肌腱发育中的相互作用。我们的长期目标是 利用MSC设计开发灵感的LOX靶向疗法以改善肌腱机械性能 属性。

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.