Dysfunctional mechanotransduction in senescent chondrocytes as a link between aging and osteoarthritis

衰老软骨细胞中功能失调的机械转导是衰老与骨关节炎之间的联系

• 批准号: 10313205
• 负责人: Michaela E Copp
• 金额: $ 3.73万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10313205
• 关键词: Age; Age-Months; Aging; Alleles; Biochemical; Biological Factors; Biology; CDKN2A gene; Cartilage; Cartilage Matrix; Cell Aging; Cell Cycle; Cell Cycle Arrest; Cells; Cellular Stress; Chondrocytes; Chronic Disease; DNA Damage; Data; Degenerative polyarthritis; Development; Dimethyl Sulfoxide; Environment; Flow Cytometry; Functional disorder; Gene Expression Profile; Genetic Predisposition to Disease; Histologic; Human; Hydrogels; Inflammatory; Injections; Joints; Knowledge; Link; Measures; Mechanics; Mediator of activation protein; Mitogen-Activated Protein Kinases; Modeling; Mus; Obesity; Operative Surgical Procedures; Outcome; Pathogenesis; Phenotype; Phosphorylcholine; Play; Preventive measure; Process; Public Health; Reporter; Research; Risk; Risk Factors; Role; Series; Severities; Signal Transduction; Stimulus; Testing; Tissues; Translating; Work; age related; aged; arthropathies; articular cartilage; cartilage degradation; cohort; cytokine; disability; ethylene glycol; experimental study; extracellular; healthy aging; in vivo; inhibitor/antagonist; insight; irradiation; joint injury; mechanotransduction; mouse model; response; response to injury; senescence

PROJECT SUMMARY The chronic disease osteoarthritis (OA) is the most common joint disorder and a leading cause of disability worldwide. Multiple factors are known to increase the risk of developing OA, including obesity, joint injury, and genetic predisposition, but the most significant risk factor for OA is aging itself. Cellular senescence has been described as a key phenotype associated with aging, and there is mounting evidence that the accumulation of senescent cells in the joint during both aging and in response to injury contribute to the development of OA. Another key phenotype associated with aging is a progressive dysfunction in the ability of cells to sense changes in their extracellular environment and transduce these into biochemical signals, a process called mechanotransduction. The overall objective of this proposal is to answer the question of how aging drives joint dysfunction by investigating the interplay between cellular senescence and dysfunctional mechanotransduction, and how these play a role in OA. Our preliminary data demonstrates an increased senescence induction response in aged donors (compared to younger donors) and to increasing substrate stiffnesses. Further, experiments conducted by the Co-Sponsor have revealed that aged mice are more susceptible to cartilage degradation after DMM surgery, compared to young mice. Therefore, the central hypothesis of this work is that the accumulation of senescent cells contributes to the age-related dysfunction in chondrocyte mechanotransduction, and that senescent cells display an exacerbated response to catabolic stimuli. To test this hypothesis, we will make use of a p16tdTom reporter mouse crossed with a lox-stop-lox allele to specifically mark chondrocytes, enabling our lab to quantitatively analyze the senescence burden at the single- cell level with flow cytometry. This model is advantageous compared to other murine models because it allows for the identification and separation of senescent chondrocytes that can be used for subsequent analysis. The experiments proposed in Aim 1 will assess how aged cartilage primes chondrocytes for senescence by quantifying the extent to which increased matrix stiffness and mounting DNA damage contribute to senescence induction. Aim 2 will make use of the p16tdTom reporter mouse model to explore how senescent chondrocytes differentially respond to their mechanical environment. Lastly, Aim 3 will determine how eliminating senescent chondrocytes prior to DMM surgery reduces the OA phenotype in aged mice. Collectively, these data will define the extent to which cellular senescence is a mediator of dysfunctional mechanotransduction and cartilage degradation. This proposed work will have broad implications in understanding how senescent cells respond to their mechanical environment and identify a contributing cause of age-related mechanical dysfunction in chondrocytes. These contributions will increase knowledge of the biological factors that play a role in the pathogenesis of OA and provide an explanation for how aging drives joints dysfunction.

项目概要 慢性疾病骨关节炎 (OA) 是最常见的关节疾病，也是导致残疾的主要原因 全世界。已知多种因素会增加患 OA 的风险，包括肥胖、关节损伤和 遗传倾向，但 OA 最重要的危险因素是衰老本身。细胞衰老已 被描述为与衰老相关的关键表型，并且越来越多的证据表明 关节中的衰老细胞在衰老过程中以及对损伤的反应都会导致骨关节炎的发生。 与衰老相关的另一个关键表型是细胞感知变化能力的进行性功能障碍 在细胞外环境中并将其转导为生化信号，这一过程称为 力传导。该提案的总体目标是回答衰老如何驱动关节的问题 通过研究细胞衰老和机械转导功能障碍之间的相互作用来发现功能障碍， 以及它们如何在 OA 中发挥作用。我们的初步数据表明衰老诱导增加 老年捐赠者（与年轻捐赠者相比）的反应以及对增加基质硬度的反应。更远， 共同发起人进行的实验表明，老年小鼠更容易受到软骨的影响 与年轻小鼠相比，DMM 手术后降解。因此，本工作的中心假设是 衰老细胞的积累导致软骨细胞中与年龄相关的功能障碍 机械转导，并且衰老细胞对分解代谢刺激表现出加剧的反应。 为了验证这一假设，我们将利用与 lox-stop-lox 等位基因杂交的 p16tdTom 报告小鼠 专门标记软骨细胞，使我们的实验室能够定量分析单细胞的衰老负担 使用流式细胞仪检测细胞水平。与其他小鼠模型相比，该模型具有优势，因为它允许 用于识别和分离可用于后续分析的衰老软骨细胞。这 目标 1 中提出的实验将评估老化软骨如何通过以下方式启动软骨细胞衰老： 量化基质刚度增加和 DNA 损伤增加对衰老的影响程度 就职。目标2将利用p16tdTom报告小鼠模型来探索衰老软骨细胞如何 对机械环境的反应不同。最后，目标 3 将确定如何消除衰老 DMM 手术前的软骨细胞降低了老年小鼠的 OA 表型。总的来说，这些数据将定义 细胞衰老在多大程度上是机械传导和软骨功能障碍的调节因素 降解。这项拟议的工作将对理解衰老细胞如何响应具有广泛的意义 他们的机械环境并确定与年龄相关的机械功能障碍的促成原因 软骨细胞。这些贡献将增加对在疾病中发挥作用的生物因素的了解。 OA 的发病机制，并为衰老如何导致关节功能障碍提供解释。