Biomechanics of the Primitive Matrix in Embryonic Cartilage and Meniscus

这笔赠款将支持软骨和半月板发育的研究。膝关节疼痛影响大约25%的成年人，导致活动受限和生活质量受损。膝关节疼痛通常是由关节软骨和半月板这两个关节组织的退化引起的。这种退化可能是疾病和/或伤害的结果。关节软骨覆盖在骨骼的末端。从力学上讲，关节软骨在膝关节中提供压缩负荷和能量消耗。半月板是另一种膝关节结构，它增加了关节的稳定性。尽管经过了几十年的努力，但在软骨和半月板的再生方面取得的成功有限。一个主要的障碍是我们不知道这两个组织是如何在胚胎发育期间形成的。这项工作将结合新的纳米技术、显微解剖和基因表达工具，以项目将研究这两个组织在小鼠膝盖从怀孕到新生儿的发育。结果将提供关于导致这两个组织产生的初始分子事件的新见解。这将建立一个新的工程基准，可用于再生医学努力恢复软骨和半月板的生物力学功能。教育和外展活动将与研究目标相结合，让学员更好地了解生物力学。这些活动将包括高级设计项目、科学工作坊、博物馆展览和YouTube速成课程。关节软骨和半月板具有不同的细胞外基质(ECM)。软骨ECM主要由II型胶原纤维和蛋白多糖组成，半月板ECM主要由环状I型胶原纤维组成。初步数据显示，在胚胎期，两种组织的原始基质都普遍存在VI型胶原和Perlecan，它们是细胞外基质(PCM)的生物标志物。因此，这项工作将检验胚胎原始基质类似成熟组织的PCM的假设，并阐明这种PCM样原始基质在细胞机械生物学和基质发育中的作用。这项工作将1)确定原始基质分离成PCM和ECM的临界时间点，2)通过原子力显微镜(AFM)纳米力学测试来阐明原始基质的生物力学演化，3)确定硫酸糖胺聚糖(SGAGs)在原始基质生物力学和细胞力学转导中的作用。将软骨和半月板放在一起研究，这项工作将确定有助于这两个组织形成的共同和不同的分子事件。总而言之，该项目将在软骨和半月板的初始形成过程中产生关于分子、结构和力学事件的新知识，为指导组织再生和疾病干预提供新的基础。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This grant will support research on the development of cartilage and meniscus. Knee joint pain affects approximately 25 percent of adults, resulting in limited mobility and impaired life quality. Knee pain is often caused by the degeneration of two joint tissues, articular cartilage and meniscus. This degradation can be the result of disease and/or injury. Articular cartilage covers the ends of bones. Mechanically speaking, articular cartilage provides compressive load bearing and energy dissipation in the knee. The meniscus, another knee structure, increases join stability. Despite decades of efforts, there has been limited success in the regeneration of cartilage and meniscus. One major obstacle is that we do not understand how the two tissues are formed during embryonic development. This work will combine novel nanotechnology, microdissection and gene expression tools, to project will study the development of these two tissues from gestation to newborn ages in mouse knees. Outcomes will provide new insights about the initial molecular events that give rise to these two tissues. This will establish a new engineering benchmarks that can be used in regenerative medicine efforts to restore cartilage and meniscus biomechanical functions. Education and outreach activities will be integrated with the research goal to give trainees a better understanding of biomechanics. These activities will include senior design projects, science workshops, museum exhibitions and YouTube crash courses.Articular cartilage and meniscus have distinct extracellular matrices (ECMs). Cartilage ECM is mainly composed of type II collagen fibrils and proteoglycans, while meniscus ECM is dominated by circumferential type I collagen fibers. Preliminary data show that at the embryonic stage, the primitive matrices of both tissues show ubiquitous presence of type VI collagen and perlecan, the biomarkers of pericellular matrix (PCM). This work will thus test the hypothesis that the embryonic primitive matrix resembles the PCM of mature tissues, and elucidate the roles of this PCM-like primitive matrix in cell mechanobiology and matrix development. This work will 1) identify the critical time point, at which the primitive matrix separates into the PCM and bulk of ECM, 2) elucidate the biomechanical evolvement of the primitive matrix via atomic force microscopy (AFM)-based nanomechanical tests, and 3) determine the contribution of sulfated glycosaminoglycans (sGAGs) in the primitive matrix biomechanics and cell mechanotransduction. Studying cartilage and meniscus together, this work will identify the common and differentiated molecular events that contribute to the formation of the two tissues. In conclusion, this project will generate new knowledge on the molecular, structural and mechanical events during the initial formation of cartilage and meniscus, providing a new basis for guiding tissue regeneration and disease intervention.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.