Purinergic G protein signal integration in nociceptors

慢性疼痛每年影响超过5000万美国人，导致生活质量下降，生产力下降和医疗保健消费方面的巨大个人和社会成本。改善急性和慢性疼痛状况的治疗需要彻底了解疼痛刺激的传递和感知的过程。发现急性和慢性疼痛的分子和细胞机制对于开发新的治疗方法至关重要，特别是在调节从急性疼痛向慢性疼痛转变的机制中。我们实验室最近的研究已经确定了一种内源性镇痛机制，该机制存在于传递疼痛的外周感觉神经元中，并由二磷酸腺苷（ADP）的G蛋白偶联受体（GPCR）介导。本项目将研究ADP受体通过Gi/o信号传导在炎症损伤引起的痛觉过敏中的作用，GPCR激酶GRK 2和GRK 3在痛觉过敏过程中对P2 Y信号的调节，并将探索这些受体在改善腺苷酸环化酶介导的痛觉过敏中非常有效的假设，腺苷酸环化酶是炎症疼痛的基本成分。具体目的1研究GRK 2和GRK 3在背根神经节（DRG）神经元中的分布及其对P2 Y信号的调节。具体目标2将确定GRK 2和GRK 3是否在炎症损伤的情况下共同调节，并将使用实时cAMP成像在体外检查改变的GRK信号传导对腺苷酸环化酶的P2 Y受体抑制的影响。具体目标3将确定P2 Y信号调节的变化在多大程度上有助于体内炎性痛觉过敏的解决，以及这些途径的操纵是否可以提供一种治疗炎性疼痛的新方法。该建议将研究Gi/o偶联P2 Y受体作为新型镇痛药物靶点的价值，并将促进我们对外周神经系统中调节GPCR功能和伤害性处理的基本机制的理解。

DESCRIPTION (provided by applicant): Chronic pain affects more than 50 million Americans per year, resulting in extraordinary personal and societal costs in diminished quality of life, los productivity and health care consumption. Improved treatments of acute and chronic pain conditions require a thorough understanding of the processes underlying the transmission and perception of painful stimuli. Discovery of the molecular and cellular mechanisms underlying acute and chronic pain is critical to the development of new treatments, particularly in mechanisms regulating the transition from acute to chronic pain. Recent studies from our laboratory have identified an endogenous analgesic mechanism that is present in peripheral sensory neurons conveying pain and is mediated by G protein-coupled receptors (GPCRs) for adenosine diphosphate (ADP). This project will investigate the role of ADP receptors signaling through Gi/o in hyperalgesia resulting from inflammatory injury, the regulation of P2Y signaling by GPCR kinases GRK2 and GRK3 during hyperalgesia, and will explore the hypothesis that these receptors are highly effective in ameliorating hyperalgesia mediated by adenylyl cyclase, a fundamental component of inflammatory pain. Specific Aim 1 will investigate the distribution of GRK2 and GRK3 in dorsal root ganglion (DRG) neurons and their regulation of P2Y signaling in vitro. Specific Aim 2 will determine whether GRK2 and GRK3 are co-regulated in the setting of inflammatory injury, and will examine the impact of altered GRK signaling on P2Y receptor inhibition of adenylyl cyclase using real-time cAMP imaging in vitro. Specific Aim 3 will determine the extent to which changes in the regulation of P2Y signaling contribute to the resolution of inflammatory hyperalgesia in vivo and whether manipulation of these pathways may provide a novel approach to the treatment of inflammatory pain. This proposal will examine the value of Gi/o-coupled P2Y receptors as targets for novel analgesic drugs, and will advance our understanding of fundamental mechanisms regulating GPCR function and nociceptive processing in the peripheral nervous system.