Roles of the superficial zone in mature articular cartilage

项目摘要/摘要 滑膜关节对于全面的运动和生活质量是必不可少的。不幸的是，关节--和关节 尤其是软骨--极易患先天性、损伤和年龄相关的疾病，导致 退变，反映软骨固有修复能力较差。当前的临床干预措施不能满足要求 对关节软骨的广泛需求，在很大程度上是由于缺乏对细胞的关键知识 控制关节软骨正常功能的机制，如润滑和组织维护 成长中的青少年和青壮年。为了推进这些战略，需要更多关于 人关节软骨发育及对环境变化适应/反应的基本机制 活着。关节软骨最浅的一层负责将蛋白多糖(润滑剂)分泌到 允许无摩擦运动的关节囊。许多研究都把这一点作为他们的首要任务 功能，增加润滑性已显示出治疗疾病的希望。这个项目将需要更广泛的 明确定义这些细胞的独特特征和其他潜在功能的方法 作为治疗方法的目标。特别是，这项研究将重点放在表层细胞的相互作用上 下面有关节软骨细胞。我的赞助商实验室的发育研究和我拥有的初步数据 从成年小鼠收集的数据提供了有力的证据，表明浅表区不起祖细胞的作用 关节软骨细胞的数量，这表明表层细胞是独一无二的 关节软骨细胞。因此，我假设关节中有明显的浅表区细胞。 软骨，但它们与底层关节软骨细胞的协调功能促进了持续的， 关节软骨的功能组织。为了检验这一假设，在目标1中，我将描述唯一的 浅层细胞在生长和损伤反应中的特性与关节的比较 软骨细胞。在目标2中，我将直接测试成年动物对浅层细胞的需求。在AIM 3、我将探索表层细胞和关节软骨细胞之间协调功能的机制 保持成熟的关节软骨结构。我将使用多种分析工具，包括组织形态计量学， 共聚焦成像，纳米级机械测试，结合RNA测序和原位 杂交。条件性小鼠模型，包括我们的转基因Prg4Creer等位基因靶向表面区 细胞，将在成人期和创伤(DMM模型)后进行检查，这将显著改变 关节中的机械载荷。拟议的研究将提供有关以下机制的基本知识 浅表区细胞的功能和对损伤/改变的机械负荷的反应。数据和 来自该项目的见解将被证明是设想和测试未来治疗联合战略的关键，该战略旨在 表面区单元，为项目提供广泛的相关性和重要性，并提供了一个坚实的平台 这为我在生物医学和转化医学研究方面建立了独立的职业生涯。

PROJECT SUMMARY/ABSTRACT Synovial joints are essential for full range of motion and quality of life. Unfortunately, the joints -and articular cartilage in particular- are highly susceptible to congenital-, injury- and age-related diseases that lead to degeneration, a reflection of poor intrinsic cartilage repair capacity. Current clinical interventions do not meet the wide range of demands on articular cartilage due, in large part, to lack of crucial knowledge on the cellular mechanisms that govern normal functions of articular cartilage such as lubrication and tissue maintenance growing adolescents and young adults. In order to advance these strategies, more information is needed on basic mechanisms of articular cartilage development and adaptation/response to environmental changes in vivo. The superficial most layer of articular cartilage is responsible for secreting proteoglycans (lubricants) into the joint capsule that allow for frictionless movement. Many studies have focused on this as their primary function, and increasing lubrication has shown promise for disease treatment. This project will take a broader approach to clearly define unique characteristics and other potential functions for these cells that could be targeted for therapeutic approaches. In particular, this study will focus on interactions of superficial zone cells with underlying articular chondrocytes. Developmental studies by my sponsor's lab and preliminary data I have gathered from adult mice provide strong evidence that the superficial zone does not function as a progenitor population for underlying articular chondrocytes, and instead suggests that superficial cells are unique from articular chondrocytes. Thus, I hypothesize that superficial zone cells are maintained distinctly in articular cartilage, but that their coordinated functions with underlying articular chondrocytes promote sustained, functional organization of articular cartilage. To test this hypothesis, in Aim 1 I will characterize the unique properties of superficial zone cells during growth and during their response to damage compared to articular chondrocytes. In Aim 2, I will directly test the requirement of the superficial zone cells in adult animals. In Aim 3, I will explore mechanisms of coordinated functions between superficial cells and articular chondrocytes to maintain mature articular cartilage structure. I will use multiple analytical tools including histomorphometry, confocal imaging, and nano-scale mechanical testing in combination with RNA sequencing and in situ hybridization. Conditional mouse models, including our transgenic Prg4CreER allele to target superficial zone cells, will be examined at adult stages and following a traumatic injury (DMM-model) that significantly alters mechanical loading in the joint. The proposed studies will provide essential knowledge on mechanisms that underlie superficial zone cell functions and responses to damage/altered mechanical load. The data and insights from the project will prove essential to envision and test future therapeutic joint strategies that target superficial zone cells, providing broad relevance and importance to the project and offering a solid platform on which to establish my independent career in biomedical and translational medicine research.