The role of mitochondrial Damage Associated Molecular Patterns (mDAMPs) in posttraumatic osteoarthritis.

项目总结/摘要 该申请旨在资助NIAMS K 08接受者在她过渡到研究期间 独立主要目的是研究线粒体损伤相关分子在细胞凋亡中的作用。 软骨损伤后和创伤后骨关节炎（PTOA）发展中的mDAMPs模式。 在许多组织中，损伤诱导的线粒体功能障碍导致细胞释放mDAMPs进入线粒体。 细胞外环境，其使炎症持续并导致持续的组织损伤。最近的工作， 在申请人的K 08奖期间进行，证明线粒体功能障碍是一种急性反应， 重要的是，有丝分裂保护治疗可以防止细胞死亡和软骨损伤， 退化然而，线粒体功能障碍导致PTOA的基本机制尚不清楚， mDAMPs尚未在软骨中进行研究。为了检验mDAMP释放的假设， 从软骨细胞经历损伤诱导的线粒体功能障碍，这些损伤信号是 与临床关节创伤相关，我们将在四个不同的模型系统中测量mDAMP。 目的1的目标是确定启动mDAMP释放的特定信号。首先，软骨细胞将 使用已知在其它细胞类型中诱导mDAMP释放的几种刺激物在体外应激。的抑制剂 还将测试线粒体功能障碍和线粒体自噬阻断mDAMP释放的能力。接下来我们 将确定对软骨外植体的机械损伤是否导致mDAMP离体释放。目标1的结果 将提供如何触发mDAMP释放的见解，以及如何在治疗上操纵它。 目的2将分析马滑液中的mDAMP，以确定关节损伤是否导致mDAMP释放 in vivo.将在来自先前研究的库存滑液中测量mDAMP浓度，其中马 有实验性关节损伤，有和没有关节内线粒体保护治疗。为了确定mDAMP是否 释放与自然发生的疾病有关，将在马滑液中测量mDAMP， 临床急性关节创伤患者。目标2的结果将确定线粒体保护是否可以防止mDAMP 在体内释放，并且如果滑液mDAMP是早期软骨/骨损伤的有用指标。 本提案以申请人的K 08研究为基础，并利用这些研究期间生成的样本， 使拟议的目标能够在两年的时间框架内实现。这些研究代表了 独立于申请人的导师。Delco博士独自提出了研究概念， 实验，写的建议，并将负责项目监督。通过建立一个新的领域， 该奖项将使Delco博士能够建立一个独立的研究计划，并继续 在骨关节炎和再生医学中发展线粒体生物学的利基。了解角色 mDAMPs有可能改变我们诊断和治疗关节损伤的方式。

PROJECT SUMMARY/ABSTRACT This application seeks funding to support a NIAMS K08 recipient during her transition to research independence. The broad objective is to investigate the role of mitochondrial Damage-Associated Molecular Patterns (mDAMPs) after cartilage injury and in the development of posttraumatic osteoarthritis (PTOA). In many tissues, injury-induced mitochondrial dysfunction causes cells to release mDAMPs into the extracellular environment, which perpetuates inflammation and leads to ongoing tissue damage. Recent work, performed during the applicant’s K08 award, demonstrated that mitochondrial dysfunction is an acute response of chondrocytes to cartilage injury, and importantly, mitoprotective therapy prevents cell death and cartilage degeneration. However, the basic mechanisms whereby mitochondrial dysfunction leads to PTOA are not well understood, and mDAMPs have not been studied in cartilage. To test the hypothesis that mDAMPs are released from chondrocytes undergoing injury-induced mitochondrial dysfunction, and that these damage signals are associated with clinical joint trauma, we will measure mDAMPs in four different model systems. The goal of Aim 1 is to identify specific signals that initiate mDAMP release. First, chondrocytes will be stressed in vitro using several stimuli known to induce mDAMP release in other cell types. Inhibitors of mitochondrial dysfunction and mitophagy will also be tested for their ability to block mDAMP release. Next, we will determine if mechanical injury to cartilage explants results in mDAMP release ex vivo. The results of Aim 1 will provide insight into how mDAMP release is triggered, and how it may be manipulated therapeutically. Aim 2 will analyze mDAMPs in equine synovial fluid to determine if articular injury results in mDAMP release in vivo. mDAMP concentration will be measured in banked synovial fluid from previous studies, where horses had experimental joint injury, with and without intraarticular mitoprotective therapy. To determine if mDAMP release is associated with naturally occurring disease, mDAMPs will be measured in equine synovial fluid from clinical patients with acute joint trauma. Results of Aim 2 will determine if mitoprotection can prevent mDAMP release in vivo, and if synovial fluid mDAMPs are useful indicators of early cartilage/bone injury. This proposal builds on the applicant’s K08 research, and utilizes samples generated during those studies, allowing the proposed aims to be accomplish within the 2-year time frame. These studies represent a new line of inquiry, independent from the applicant’s mentor. Dr. Delco solely generated the research concept, designed the experiments, wrote the proposal, and will be responsible for project oversight. By establishing a new area of research within the field, this award will allow Dr. Delco to build an independent research program and continue to develop a niche in mitochondrial biology in osteoarthritis and regenerative medicine. Understanding the role of mDAMPs has the near-term potential to change the way we diagnose and treat joint injury.