Mechanisms of Primary Cilia Regulating Tendon Enthesis Development and Regeneration

项目总结 在60岁以上的人群中，有40%经历过肩袖撕裂。肩袖撕裂失败率高 手术修复或非手术治疗使其成为临床上的一大挑战。结果失败了 伴有肌腱-骨止点(肌腱凹陷)处的瘢痕组织形成，组织紊乱 建筑和功能退化。有效疗法的发展一直受到有限的限制 关于雌蕊发育生物学和机械生物学的知识，以及对 内生机制支配着成虫的发病机制和愈合。为了弥合这一知识鸿沟， 目前的提案试图阐明肌腱吻合是如何对其机械和生化反应的 在发育和愈合过程中的环境。众所周知，机械力和机械力的组合 不同的途径，包括Hedgehog(HH)信号，驱动末端的形成，促进成熟的重塑 齿槽，并影响齿槽愈合。最近，我们的研究表明，初级纤毛是一种孤立的 从哺乳动物细胞表面伸出的天线，可能作为机械转导和 HH信令。在我们以前工作的基础上，这项建议的目的是获得一个机械性的理解 初级纤毛在集聚和同步机械信号和HH信号中的作用 发展和治愈。为了实现这一目标，我们将确定纤毛虫的身份和活性。 成虫发育和机械适应过程中的细胞(特定目标1)和评估再生 纤毛凹陷细胞促进凹陷愈合的能力(特定目标2)。我们将使用的方法 包括纤毛标记和纤毛缺失转基因小鼠模型、不同已建立的负载模型、细胞 移植和转录学分析，结合结构、成分和生物力学 评估分析。在本项目结束时，我们希望发现新的纤毛调节机制。 体内末端机械适应过程中的转导途径，并提出了新的机制 纤毛将机械信号转换为细胞信号事件。初生纤毛在成虫过程中作用的新发现 治愈将引导治疗新的药理和机械生物学疗法的发展 肩袖撕裂。

PROJECT SUMMARY 40% of the population over the age of 60 experiences a rotator cuff tear. The high failure rates of rotator cuff tear after surgical repair or non-surgical treatment make it a major clinical challenge. The outcome failures accompany the formation of scar tissues at the tendon-to-bone insertion (tendon enthesis) with disorganized architecture and deteriorated function. Development of effective therapeutics has been hampered by limited knowledge of enthesis development biology and mechanobiology and an incomplete understanding of endogenous mechanisms governing enthesis pathogenesis and healing. To bridge this knowledge gap, the current proposal seeks to elucidate how tendon enthesis responds to its mechanical and biochemical environment during development and healing processes. It is known that a combination of mechanical force and distinct pathways, including hedgehog (Hh) signaling, drive enthesis formation, promote remodeling of mature enthesis, and affect enthesis healing. Recently, our studies have indicated that the primary cilium, a solitary antenna protruding from mammalian cell surface, potentially functions as a hub for mechanotransduction and Hh signaling. Building on our previous work, the objective of this proposal is to gain a mechanistic understanding of the role of primary cilia in concentrating and synchronizing mechanical and Hh signals during enthesis development and healing. To achieve this objective, we will determine identities and activities of ciliated enthesis cells during enthesis development and mechanical adaptation (Specific Aim 1) and evaluate the regenerative capacity of ciliated enthesis cells for improving enthesis healing (Specific Aim 2). The approaches we will use include cilia-labeled and cilia-deleted transgenic mouse models, different established loading models, cell transplantation, and transcriptomics analysis, combined with structural, compositional, and biomechanical evaluation assays. At the conclusion of this project, we expect to identify new cilia-regulated mechano- transduction pathways during in vivo enthesis mechanical adaptation and suggest novel mechanisms by which cilia convert mechanical cues to cellular signaling events. The new findings of the role of primary cilia in enthesis healing will guide the development of novel pharmacological and mechanobiology therapeutics for treating rotator cuff tears.