Receptor-mediated dysfunction of satellite glia and uninjured sensory neurons as a novel link between referred neuropathic pain and bladder disease

项目摘要 牵涉性疼痛在研究中研究不足，在临床中也知之甚少，特别是对于患有 膀胱疾病膀胱疼痛可以显着降低生活质量，这是放大了未承认或 治疗不当的皮肤疼痛。膀胱或躯体疼痛的诊断由于缺乏 明显的病理学，加剧了寻找有效治疗方法的挑战。虽然根 这种牵涉性疼痛的原因尚不清楚，它可能依赖于内脏和皮肤传入的相互作用，称为 内脏-躯体串扰脊髓牵涉痛的机制不能解释为什么 患有骨盆疼痛的患者具有下肢皮肤的感觉神经支配丧失，这可诊断为神经性疼痛。 初步数据显示，小鼠后爪机械超敏反应与膀胱炎症密切相关 与神经损伤表型相似，反映了患者的膀胱下肢敏感性 炎症或神经损伤。在周围神经系统中，背根神经节（DRG）神经元是 在功能和神经支配组织中广泛多样，其中损伤和未损伤的神经元及其周围 卫星神经胶质细胞，在受伤后发生变化，导致疼痛。未损伤膀胱之间的内脏-躯体串扰 或背根神经节中的躯体神经元可能引起牵涉痛，但缺乏关于膀胱的信息， DRG中的神经元串扰。逆行神经元追踪研究证实DRG可以同时容纳 膀胱和后爪皮肤感觉神经元强烈支持这种可能性。这项研究将测试 损伤后DRG中的内脏-躯体串扰导致过度兴奋的生理性 未受伤回路的反应，由其感觉神经元的功能变化介导， 改变了卫星神经胶质的信号为此，神经生理学实验将利用完整的DRG， 维持神经元和卫星神经胶质之间的局部通信，包括一种新的离体制剂， 使小鼠从后爪皮肤到脊髓的感觉回路完好无损。与分子 蛋白质表达的测定，实验将确定驱动示踪剂标记的 通过探测卫星胶质细胞和两个关键膜受体的激活，瞬时电位， 通道V成员1（TRPV1），也称为辣椒素受体，和嘌呤受体3（P2X3），广泛分布于 研究了腺苷三磷酸受体，这两个都是知之甚少的涉及疼痛，导致 膀胱炎症或神经损伤。目的1旨在研究未损伤的后爪神经元如何 在丙烯醛诱导的膀胱炎后发生生理学改变，这些改变可能是由 TRPV1或P2X3的变化。目的2将探讨未损伤的膀胱感觉神经元如何受到Sodium的影响 神经损伤，下肢神经性疼痛的稳健模型。总的来说，这些数据将有助于阐明感官 膀胱牵涉痛的新生物学机制--背根神经节神经元串扰 疾病，并为改善诊断和新的，有效的治疗方法提供起点。

PROJECT SUMMARY Referred pain is both understudied in research and poorly understood in the clinic, particularly for patients with bladder disease. Bladder pain can significantly lessen quality of life, which is amplified by unacknowledged or improperly treated pain from the skin. Diagnosis of referred bladder or somatic pain is obfuscated by a lack of obvious pathology, exacerbating the challenges of finding effective therapeutic approaches. Though the root cause of such referred pain is unknown, it likely relies on visceral and skin afferent interactions, termed viscerosomatic crosstalk. Mechanisms of referred pain attributed to the spinal cord fail to explain why patients with pelvic pain have sensory innervation loss of the lower limb skin that is diagnostic for neuropathic pain. Preliminary data shows that mechanical hypersensitivity in hind paws of mice with bladder inflammation closely resembles nerve injury phenotypes and reflect patient experiences of lower limb sensitivity from bladder inflammation or nerve damage. In the peripheral nervous system, dorsal root ganglia (DRG) neurons are widely diverse in function and in innervating tissue, where injured and uninjured neurons, and their surrounding satellite glia, undergo changes after injury that drive pain. Viscerosomatic crosstalk between uninjured bladder or somatic neurons in DRG could be causing referred pain, but there is a dearth of information about bladder neuron crosstalk in the DRG. Retrograde neuronal tracing studies confirming DRG can co-housing both bladder and hind paw skin sensory neurons strongly support this possibility. The proposed research will test the hypothesis that viscerosomatic crosstalk in DRG after injury results in hyperexcitable physiological responses of the uninjured circuit, mediated by functional changes in their sensory neurons and altered signaling with satellite glia. To do this, neurophysiology experiments will utilize intact DRGs to maintain local communication between neurons and satellite glia, including a novel ex vivo preparation that leaves the mouse sensory circuit from the hind paw skin to the spinal cord intact. Together with molecular assays of protein expression, experiments will determine the mechanisms driving activation of tracer-labeled uninjured neurons by probing activation of satellite glia and two key membrane receptors, transient potential channel V member 1 (TRPV1), also known as the capsaicin receptor, and Purinocepter 3 (P2X3), a widely studied adenosine triphosphate receptor, both of which are poorly understood in referred pain that results from bladder inflammation or nerve injury. Aim 1 is designed to investigate how uninjured hind paw neurons are physiologically altered after acrolein-induced cystitis, and the possibility that these alterations are mediated by changes in TRPV1 or P2X3. Aim 2 will explore how uninjured bladder sensory neurons are affected by Spared Nerve Injury, a robust model of lower limb neuropathic pain. Collectively, these data will help elucidate sensory neuron crosstalk in DRG as a new biological mechanism underlying referred pain in patients with bladder disease and provide a starting point for improved diagnosis and novel, effective therapeutic approaches.