Modulation of Inflammation in Osteoarthritis via CD14-mediated pattern recognition

摘要 骨关节炎（OA）是导致成人残疾的主要原因，引起慢性进行性关节疼痛和组织损伤。 整个关节的损伤。目前没有有效的医学治疗方法可以预防关节炎的进展。 OA的恶化、疼痛和残疾特征。尽管众所周知炎症和骨- 重塑是OA疼痛和病理学的主要驱动因素，目前尚不清楚哪些分子途径直接 驱动慢性OA疼痛和疾病进展，或者是治疗开发的关键目标。我们的实验室 显示了CD 14缺陷，CD 14是巨噬细胞表达的炎性模式识别受体， 其他骨髓细胞类型，防止OA相关的骨重塑和疼痛相关的关节功能障碍 在小鼠膝关节损伤后。在患者中，CD 14在关节液中增加，并与关节内 巨噬细胞浸润以及疼痛严重程度。该受体促进Toll样受体（TLR）信号传导。 TLR是先天性免疫传感器，其是响应于免疫应答的慢性炎症的重要初始触发剂。 非感染性组织损伤此外，我们的团队最近已经证明TLR信号传导对于 通过直接刺激小鼠膝关节OA疼痛的传导（伤害感受）神经元， 背根神经节（DRG），支配膝关节。在本提案中，我们将检验CD 14在 包括巨噬细胞在内的骨髓细胞促进OA疼痛相关的病理学（骨重塑和 炎症），而CD 14也通过直接致敏神经元来增加OA疼痛， 关节炎我们将利用体外技术和内侧半月板（DMM）的小鼠去稳定化 OA模型，以了解CD 14驱动OA病理的细胞和分子机制， 关节组织的炎症。具体而言，在目标1中，我们将使用多学科方法来确定如何 CD 14的遗传缺陷改变了OA进展过程中的炎症和骨重塑， DMM模型。我们将确定骨髓细胞对炎症和骨重建的贡献， 使用骨髓（BM）嵌合小鼠模型。最后，我们将测试CD 14对分化的影响。 驱动骨重塑的细胞（破骨细胞）和从骨髓产生疼痛的炎症介质 细胞类型。在目的2中，我们将表征CD 14对TLR介导的DRG神经元活化和关节炎的影响。 痛苦我们将使用与OA相关的TLR刺激来评估体外DRG反应，比较WT和 CD 14缺陷细胞。我们还将比较对关节注射TLR刺激物的疼痛反应， 预期在CD 14缺陷型菌株中DRG反应和疼痛都将减弱。最后，在目标3中， 测试CD 14的药理学靶向是否减少了DMM诱导的损伤后的OA进展和疼痛。 这项研究将详细说明分子和细胞框架，以设计未来的抗炎药物。 针对CD 14和TLR介导机制的OA治疗剂。

ABSTRACT Osteoarthritis (OA) is a leading cause of disability in adults, causing chronic progressive joint pain and tissue damage throughout the joint. No current medical treatments are effective at preventing the progressive joint deterioration, pain and disability characteristic of OA. Although it is known that inflammation and bone- remodeling are major drivers of OA pain and pathology, it is not yet clear which molecular pathways directly drive chronic OA pain and disease progression or are key targets for therapeutic development. Our lab has shown that deficiency of CD14, an inflammatory pattern-recognition receptor expressed by macrophages and other myeloid cell types, protects against OA-associated bone-remodeling and pain-related joint dysfunction after knee injury in mice. In patients, CD14 is increased in joint fluid and associated with intra-articular macrophage infiltration as well as pain severity. This receptor facilitates Toll-like receptor (TLR) signaling. TLRs are innate immune sensors which are important initial triggers of chronic inflammation in response to non-infectious tissue damage. In addition, our team has recently demonstrated that TLR-signaling is critical to development of knee OA pain in mice, via direct stimulation of pain-transmitting (nociceptive) neurons in the dorsal root ganglia (DRG) that innervate the knee. In this proposal, we will test the hypothesis that CD14 on myeloid cells including macrophages promotes OA pain-related pathology (bone remodelling and inflammation), while CD14 also augments OA pain by directly sensitizing neurons innervating the arthritic joint. We will utilize in vitro techniques and the murine destabilization of the medial meniscus (DMM) model of OA, to understand the cellular and molecular mechanisms by which CD14 drives OA pathology and inflammation in joint tissues. Specifically, in Aim 1 we will use a multi-disciplinary approach to determine how genetic deficiency of CD14 modifies inflammation and bone-remodeling during progression of OA, using the DMM model. We will determine the contribution of myeloid cells to inflammation and bone-remodeling in the model by using bone marrow (BM) chimeric mice. Lastly, we will test the effects of CD14 on differentiation of cells that drive bone-remodeling (osteoclasts) and production of inflammatory mediators of pain from myeloid cell types. In Aim 2 we will characterize effects of CD14 on TLR-mediated DRG neuronal activation and joint pain. We will use TLR stimuli with relevance to OA to evaluate DRG responses in vitro, comparing WT and CD14-deficient cells. We will additionally compare pain responses to injection of TLR-stimuli into the joint, and expect that both DRG responses and pain will be blunted in the CD14 deficient strain. Finally, in Aim 3 we will test whether pharmacological targeting of CD14 reduces OA progression and pain after DMM-induced injury. This study will then specify the molecular and cellular framework to design future anti-inflammatory therapeutics for OA aimed at CD14- and TLR-mediated mechanisms.