The Role of Mechanosensation Pathways in Osteoarthritis Joint Damage and Pain

项目摘要 膝关节骨关节炎（OA）是一种痛苦的慢性疾病，影响着美国2700万人。膝关节OA是 其特征在于所有关节组织的进行性损伤和重塑。OA的主要特征是关节疼痛 X光显示关节间隙变窄生物力学和炎症因子在两种关节中起重要作用 疼痛和损伤，但这些途径如何相互作用，并促进机械敏化的感觉 神经元未知。最近，我们发现感觉神经元机械敏感离子通道Piezo 2是一个关键， 在OA的内侧半月板（DMM）小鼠模型的不稳定性中的机械致敏作用的贡献者。 此外，我们已经证明，神经生长因子诱导的关节炎症是依赖于伤害感受器的表达 的Piezo 2，表明Piezo 2信号可能有助于神经免疫相互作用。我们终于有 表明巨噬细胞浸润是机械致敏的关键因素， OA。伤害感受器信号有助于促进免疫细胞的这种募集，但Piezo 2通路是如何 涉及的情况尚不清楚。因此，本补充文件是对现有的具体目标1的扩展， 家长计划。特别是，我们将利用我们正在进行的伤害感受器特异性Piezo 2条件性研究， 基因敲除小鼠现在包括在这些小鼠中发生的神经免疫变化的检查，在两种性别中。 这将包括使用一种新型成像技术--对透明的膝关节和脊柱进行光片成像 图10示出了在柱/DRG组织中观察巨噬细胞的方法，以便以体积表示来可视化这些组织中的巨噬细胞。的 这里概述的研究将通过提供炎症相互作用的信息来填补知识上的差距 和机械刺激产生机械敏化。这项建议旨在回答以下问题： Piezo 2在炎症机械致敏中的作用是什么？光片成像能用来 量化腰椎背根神经节中的巨噬细胞数量我们假设机械刺激对于 炎性机械致敏。此外，我们假设在DRG中的巨噬细胞募集是 机械敏化的基本部分，并且通过敲除Piezo 2将抑制募集。 成功完成这一补充将提高我们的理解伤害感受器和免疫细胞 在Piezo 2通路的帮助下进行通信，以促进OA中的机械致敏，这可能导致 确定新的途径，以治疗疼痛和关节损伤。

Project Summary Knee osteoarthritis (OA) is a painful chronic disease affecting 27 million people in the US. Knee OA is characterized by progressive damage and remodeling of all joint tissues. Major hallmarks of OA are joint pain and joint space narrowing on x-ray. Biomechanical and inflammatory factors play an important role in both joint pain and damage, but exactly how these pathways interact and promote mechanical sensitization of sensory neurons is unknown. Recently, we identified the sensory neuron mechanosensitive ion channel Piezo2 as a key contributor to mechanical sensitization in the destabilization of the medial meniscus (DMM) mouse model of OA. In addition, we have demonstrated that NGF-induced joint inflammation is dependent on nociceptor expression of Piezo2, suggesting that Piezo2 signaling may contribute to neuroimmune interactions. Finally, we have demonstrated that macrophage infiltration is a key contributor to the development of mechanical sensitization in OA. Nociceptor signaling helps to facilitate this recruitment of immune cells, but how the Piezo2 pathway is involved is not yet known. Therefore, this supplement represents an expansion of the existing Specific Aim 1 of the parent program. In particular, we will leverage our ongoing studies in nociceptor-specific Piezo2 conditional knock-out mice to now include examination of the neuroimmune changes happening in these mice, in both sexes. This will include using a novel imaging technology – light sheet imaging of cleared knee joint and spinal column/DRG tissue in order to visualize macrophages in these tissues in a volumetric representation. The research outlined here will fill the gap in knowledge by providing information on the interaction of inflammation and mechanical stimuli in producing mechanical sensitization. This proposal aims to answer the questions of: What is the role of Piezo2 in inflammatory mechanical sensitization? And, Can light sheet imaging be used to quantify macrophage numbers in the lumbar DRGs? We hypothesize that mechanical stimuli are necessary for inflammatory mechanical sensitization. In addition, we hypothesize that macrophage recruitment in the DRGs is a fundamental part of mechanical sensitization, and that recruitment will be inhibited by knocking out Piezo2. Successful completion of this supplement will improve our understanding of how nociceptors and immune cells communicate with the help of the Piezo2 pathway to promote mechanical sensitization in OA, which may lead to the identification of novel pathways to target both pain and joint damage therapeutically.