Novel models to study dorsal root ganglion neurons in knee osteoarthritis pain

项目总结/摘要 膝关节骨关节炎（OA）是致残性疼痛的主要来源，影响近20%的45岁以上的美国成年人， 只会随着人口老龄化而增加尽管大量的研究和临床工作 发现重要的疾病修饰治疗（即，逆转关节损伤、关节置换）， 缺乏针对膝关节OA引起的疼痛的治疗方法。考虑到这种疾病的高疼痛负担（例如， 失眠，不动，抑郁），以及目前的治疗是侵入性的，缺乏长期的， 有效性差，具有严重副作用的高风险，并且作为镇痛剂不一致（例如，膝关节置换术， 神经消融和阿片类药物）-迫切需要足够的疼痛治疗方法。周围神经或背根 神经节（DRG）通常是传递疼痛的第一个神经元，因此靶向DRG可以防止异常疼痛 引发神经系统级联反应，导致神经回路的慢性适应不良变化。 此外，DRG位于血脑屏障之外，提供了一种容易获得的治疗方法， 目标然而，重要的是要精确地靶向传导膝关节OA疼痛的DRG人群， 有益人群，如负责膝关节本体感觉和稳定的人群。最近，临床 通过精确靶向DRG在疼痛状态下的特定功能改变， 小纤维神经病变和术后疼痛。此外，基础科学疼痛研究领域有 缺乏从常用模型到临床病理学的转换，但令人兴奋的进展 都是通过在相关的媒介如人体组织中应用基础科学方法来制造的。这里我 提出，识别驱动膝OA诱导的伤害性神经元变化的DRG群体， 除了识别这些DRG群体中OA诱导的改变外，还将提供 潜在的治疗方法。在辅导K99阶段，我的导师Julie Kauer博士和我的 顾问Stuart Goodman，医学博士，博士，Gregory Corder，博士，Elizabeth Serafin，MS和Lu Chen，博士，将 支持我的职业发展和培训。基于我目前的工作，证明TRPV 1- 表达DRG群体驱动炎性损伤介导的脊髓增强，1）我将确定膝关节是否 OA通过支配膝关节的TRPV 1表达DRG神经元启动脊髓增强。（2）我会 使用TRAP分析膝关节OA疼痛中活动的DRG神经元（活动人群中的短暂性震颤） 结合行为分析、转录组学分析和电生理学技术。最后在 独立阶段3）I将使用具有人源性DRG神经元和膝组织的共培养系统 从关节成形术中恢复，以研究关节内的遗传，群体水平活动和功能变化。 骨关节炎关节环境中的DRG神经元。这将为我的未来提供线索 研究计划，并为膝关节OA疼痛的多年调查产生可资助的项目。

PROJECT SUMMARY/ABSTRACT Knee osteoarthritis (OA) is a leading source of disabling pain, affecting nearly 20% of US adults over 45, which will only increase as our population ages. Although remarkable research and clinical efforts are being poured into discovering vital disease-modifying treatments (i.e., reversing joint damage, joint replacement), therapeutics targeting pain caused by knee OA are lacking. Given the high burden of pain in this disorder (e.g., sleeplessness, immobility, depression), and the fact that current treatments are invasive, lack long-term efficacy, carry high risk of severe side effects, and are inconsistent as analgesics (e.g., knee replacement, nerve ablation, and opioids)—adequate pain therapeutics are urgently needed. Peripheral nerves or dorsal root ganglion (DRG) are generally the first neurons to transmit pain, thus targeting DRG can prevent aberrant pain from initiating a nervous system cascade resulting in chronic, maladaptive changes to neural circuits. Furthermore, DRG are located outside of the blood brain barrier, providing an easily accessible therapeutic target. However, it is important to precisely target DRG populations transmitting knee OA pain, to preserve beneficial populations like those responsible for knee proprioception and stabilization. Relatedly, recent clinical gains have been made by precisely targeting specific functional alterations in DRG during pain states caused by small fiber neuropathy and postoperative pain. Additionally, the basic science pain research field has suffered from a lack of translation from commonly used models to clinical pathologies, but exciting advances are being made by applying basic science approaches in relevant mediums like human tissues. Here I propose that identifying the DRG populations driving knee OA-induced changes in nociceptive neural circuits in addition to identifying the OA-induced alterations within these DRG populations, will provide avenues for potential therapeutics. In the mentored K99 phase, my mentor Julie Kauer, PhD, and my advisors Stuart Goodman, MD, PhD, Gregory Corder, PhD, Elizabeth Serafin, MS, and Lu Chen, PhD, will support my career development and training. Building upon my current work demonstrating that the TRPV1- expressing DRG population drives inflammatory injury-mediated spinal potentiation, 1) I will determine if knee OA initiates spinal potentiation via TRPV1-expressing DRG neurons innervating the knee. Additionally, 2) I will profile DRG neurons active in knee OA pain using the TRAP (Transient Recombination in Active Populations) technique in combination with behavioral assays, transcriptomic analysis, and electrophysiology. Finally, in the independent phase 3) I will use a co-culture system with human-derived DRG neurons and knee tissue recovered from arthroplasties to investigate the genetic, population-level activity, and functional changes within DRG neurons in an osteoarthritic joint environment. This will generate leads to build upon in my future research program and generate fundable projects for a multiyear investigation of knee OA pain.