Osteoarthritis Progression And Sensory Pathway Alterations

项目摘要 迫切需要新的治疗药物来治疗与骨关节炎(OA)相关的疼痛。办公自动化 是一种慢性疾病，随着疾病的进展，患者可以描述不同类型的疼痛，包括疼痛 负重或关节运动，以及休息时疼痛。一些患者表现出外周和/或中枢的体征 敏化。令人信服的临床证据表明，来自骨性关节炎关节的持续外周输入会导致疼痛 和敏感化。我们建立了小鼠内侧半月板失稳(DMM)模型来研究 疾病的慢性性质和与进行性关节损伤相关的不同疼痛行为。 其主要目的是描述颈椎感觉神经支配的解剖学和功能变化。 联合。我们发现，在实验性骨性关节炎的过程中，NAV1.8的伤害性感受器经历了深刻的、 以前没有意识到的是，在所有水平上(膝关节、背根节和背角)的可塑性 精确地进化的方式。最近，感觉神经元的分类已经变得很清楚，根据 作为躯体感觉不同方面基础的分子的独特表达模式。具体来说， NaV1.8神经元由不同的功能亚群组成，包括热敏性TRPV1神经元， 机械敏感的MRGPrd C-纤维、TH+C-低阈值机械感受器(C-LTMR)和沉默的CHRNA3 纤维。与骨性关节炎疼痛潜在相关的另一个子集是TrkA+，它表达神经生长的受体 因素。我们假设，这些亚群中特定的时空变化调节了 骨性关节炎进展过程中的疼痛行为。我们的实验计划考虑了两个相辅相成的研究目标(1) 时间和空间的贡献(哪些神经在OA关节中存在和起作用，地点和时间？)； 以及(2)我们如何针对这些特定的神经元亚群来检查对疼痛行为和关节的影响 健康。具体目标1旨在定义膝关节神经支配的时间和空间神经可塑性 骨性关节炎关节病理与疼痛。我们已经使用了各种CRE/FLP驱动器来生产系列荧光报告程序 小鼠对伤害性、机械性和本体感受性(小白蛋白，PV)DRG的不同亚群具有特异性 神经元。我们将使用这些小鼠来定义膝关节神经的解剖学和功能变化，使用 共聚焦显微镜和光片显微镜、体内钙成像和特异性的瞬时化学发生沉默 神经元亚群。特定目标2旨在靶向特定神经元亚群并检测其对骨性关节炎的影响 疾病(疼痛和关节损伤)，以探索我们的发现如何转化为治疗OA的新方法 疼痛。我们将确定神经元亚群的慢性化学发生沉默对骨性关节炎疼痛的影响 和关节损伤。我们还将研究DRG亚群特有的“接受组”，以便开发 有针对性的治疗干预。我们认为，神经元亚群的识别在 OA疼痛行为将使他们能够针对疾病的特定阶段，这将 导致新的，更有效和更安全的治疗方法的骨性关节炎疼痛。

Project Summary There is an urgent need for new therapeutic agents that treat the pain associated with osteoarthritis (OA). OA is a chronic disease, and as disease progresses, patients can describe different types of pain, including pain on weightbearing or joint movement, and pain at rest. Some patients display signs of peripheral and/or central sensitization. Compelling clinical evidence suggests that ongoing peripheral input from the OA joint drives pain and sensitization. We have developed the murine DMM (destabilization of the medial meniscus) model to study the chronic nature of the disease and the different pain behaviors associated with progressive joint damage. The overarching aim is to characterize anatomical and functional alterations in the sensory innervation of the joint. We have uncovered that in the course of experimental OA, NaV1.8 nociceptors undergo profound, and previously unappreciated, plasticity at all levels (in the knee joint, in the DRG, and in the dorsal horn) in a precisely evolving manner. Recently, it has become clear that sensory neurons can be classified based on unique patterns of expression of molecules that underlie different aspects of somatic sensation. Specifically, NaV1.8 neurons comprise distinct functional subsets, including heat-sensitive TRPV1 neurons, mechanosensitive Mrgprd C-fibers, TH+ C-low threshold mechanoreceptors (C-LTMR), and silent CHRNA3 fibers. Another subset of potential relevance to OA pain is TrkA+, expressing the receptor for Nerve Growth Factor. We hypothesize that specific temporospatial changes in these subpopulations mediate the evolution of pain behaviors during OA progression. Our experimental plan considers two complementary aims to study (1) temporal and spatial contributions (which nerves are present and functional in the OA joint, where and when?); and (2) how we may target these specific neuronal subsets to examine effects on pain behaviors and joint health. Specific Aim 1 aims to define temporal and spatial neuroplasticity of knee innervation in the context of OA joint pathology and pain. We have used a variety of Cre/Flp drivers to produce lines of fluorescent reporter mice specific for distinct subsets of nociceptive, mechanosensitive, and proprioceptive (parvalbumin, PV) DRG neurons. We will use these mice to define anatomical and functional changes in knee innervation, using confocal and lightsheet microscopy, in vivo Ca2+ imaging, and transient chemogenetic silencing of specific neuronal subsets. Specific Aim 2 aims to target specific neuronal subsets and examine the effect on OA disease (pain and joint damage), in order to explore how our findings may translate to new approaches for OA pain. We will determine the effects of chronic chemogenetic silencing of neuronal subpopulations on OA pain and joint damage. We will also study the “receptome” specific to DRG subpopulations in order to develop targeted therapeutic interventions. We propose that the identification of neuronal subpopulations that mediate OA pain behaviors will allow them to be specifically targeted at specific stages of the disease and this will result in novel, more efficacious and safer therapeutic approaches to OA pain.