Trafficking-Dependent Signaling of Pain by Protease-Activated Receptors

项目摘要 慢性疼痛是一个主要的未解决的医疗问题。从急性脑梗死向急性脑梗死转变的机制 从生理性疼痛到慢性（病理性）疼痛的治疗方法知之甚少，并且目前的治疗方法不足。的 研究结肠疼痛与肠易激综合征和炎症性肠病的相关性。 在损伤和炎症过程中被激活的蛋白酶可以通过切割蛋白酶- 激活受体2（PAR 2），其激活瞬时受体电位通道并诱导持久的 过度兴奋和伤害感受。尽管蛋白酶和PAR 2与结肠疼痛有关， 持续性蛋白酶诱导疼痛的信号传导机制尚不清楚，PAR 2是否是一种 慢性疼痛的治疗靶点尚不确定。前提是PAR 2是唯一适合于传输持久 由于蛋白水解（催化）激活的不可逆机制，受体的能力， 内体信号，以及动员细胞内受体库的有效机制。因此，委员会认为， 内体PAR 2拮抗剂和动员抑制剂可有效缓解疼痛。这些概念将 在完整小鼠、小鼠和人结肠的分离节段以及培养的伤害感受神经元中进行检查。 方法包括：伤害感受的行为学评估，伤害感受器的电生理学分析 激活，以及生物物理和成像方法来评估伤害感受器中的PAR 2运输和信号传导。 表达荧光PAR 2的小鼠将用于研究PAR 2运输。靶向缺失PAR 2的小鼠， 伤害感受器和独特的内体PAR 2的脂质结合拮抗剂，将用于确定是否 伤害感受器内体中的PAR 2是持续性结肠疼痛的治疗靶点。这些研究将提供 深入了解慢性疼痛的机制和治疗。它们对靶向治疗有意义， G蛋白偶联受体;这个1,000个成员的受体家族是40%药物的靶点。由于许多 激活的受体内化并继续发出信号，有效的治疗需要内体靶向药物。

PROJECT SUMMARY Chronic pain is a major unmet medical problem. The mechanisms that underlie the transition from acute (physiological) to chronic (pathological) pain are poorly understood and current therapies are inadequate. The proposal investigates colonic pain, with relevance to irritable bowel syndrome and inflammatory bowel disease. Proteases that are activated during injury and inflammation can signal to nociceptors by cleaving protease- activated receptor-2 (PAR2), which activates transient receptor potential channels and induces long-lasting hyperexcitability and nociception. Although proteases and PAR2 have been implicated in colonic pain, the signaling mechanisms that underlie persistent protease-induced pain are far from clear, and whether PAR2 is a therapeutic target for chronic pain is uncertain. The premise is that PAR2 is uniquely suited to transmit persistent nociception due to the irreversible mechanism of proteolytic (catalytic) activation, the capacity of the receptor to signal from endosomes, and the efficient mechanisms that mobilize intracellular receptor stores. Accordingly, antagonists of endosomal PAR2 and inhibitors of mobilization provide effective pain relief. These concepts will be examined in intact mice, isolated segments of mouse and human colon, and nociceptive neurons in culture. Approaches will include: behavioral assessment of nociception, electrophysiological analysis of nociceptor activation, and biophysical and imaging approaches to assess PAR2 trafficking and signaling in nociceptors. Mice expressing fluorescent PAR2 will be used to study PAR2 trafficking. Mice with targeted deletion of PAR2 on nociceptors, and unique lipid-conjugated antagonists of endosomal PAR2, will be used to determine whether PAR2 in endosomes of nociceptors is a therapeutic target for persistent colonic pain. The studies will provide insights into the mechanisms and treatment of chronic pain. They have implications for therapeutic targeting of G protein-coupled receptors; this 1,000-member family of receptors is the target of 40% of drugs. Since many activated receptors internalize and continue to signal, effective therapy requires endosomally-targeted drugs.