Estrogen regulation of inflammatory mediator signaling

描述（由申请人提供）：数百万美国人经常报告三叉神经系统疼痛疾病。虽然疼痛并不区分男性和女性，但流行病学研究表明，女性患三叉神经痛和其他形式疼痛的风险增加。妇女更有可能报告各种暂时性和持续性疼痛，并报告比男子更严重的疼痛，更频繁的疼痛和持续时间更长的疼痛。重要的是，在受控的实验条件下，女性通常比男性对引起疼痛的刺激更敏感。我们的初步研究确定了雌激素受体1（ER 1）在大鼠三叉神经节（TG）神经元，并表明，雌二醇迅速（15分钟）增强细胞信号的两种炎症介质，缓激肽（BK）和前列腺素E2（PGE 2）在培养的TG神经元。我们的总体假设是，雌激素，通过快速信号通路，增加TG伤害感受器的炎症介质的刺激的反应性，这在增强女性的疼痛敏感性中发挥作用。具体目标1：表征雌二醇（17_-E2）对三叉神经节中BK和PGE 2信号传导的快速作用。我们将确定17_-E2作用的浓度依赖性、时间依赖性和配体依赖性，并使用siRNA敲低鉴定介导快速作用的雌激素受体。具体目标二：确定BK和PGE 2受体系统中17_-E2诱导的快速变化，这些变化是TG培养物中信号增强的原因。我们将确定BK和PGE 2信号传导效率增加的机制是否是由于细胞表面受体密度增加或信号转导效率（受体-G蛋白偶联效率或膜微区（脂筏）的运输）的变化。具体目标3：确定17_-E2对雌性大鼠口面急性炎症模型中伤害感受的影响。我们将确定是否外源性应用17_-E2在体内改变对BK，PGE_2或福尔马林的伤害性行为反应。此外，我们将评估内源性17_-E2在发情周期中对口面伤害感受的作用。这些综合研究将增加我们对雌激素通过快速信号传导机制调节大鼠三叉神经节中炎症介质BK和PGE 2的信号传导和伤害感受的后果和机制的理解。详细研究雌激素受体及其对TG中炎症介质信号传导的影响将为理解女性对疼痛的敏感性增强提供基础，并为改善疼痛药物治疗提供新的靶点。虽然疼痛并不区分男性和女性，但流行病学研究表明，女性遭受口面部和其他形式疼痛的风险增加。本文提出的综合研究将增加我们对女性性激素雌激素调节感觉神经元对疼痛刺激的反应的后果和机制的理解。这项工作将为理解女性对疼痛的敏感性增强提供基础，并为改善疼痛药物治疗提供新的靶点。

DESCRIPTION (provided by applicant): Pain disorders in the trigeminal system are reported frequently by millions of Americans. Although pain does not discriminate between men and women, epidemiological studies have demonstrated that women are at increased risk for trigeminal and other forms of pain. Women are more likely to report a variety of temporary and persistent pains and to report more severe pain, more frequent pain and pain of longer duration than men. Importantly, under controlled experimental conditions, women are generally more sensitive to pain-causing stimuli than men. Our preliminary studies identified estrogen receptor 1 (ER1) in rat trigeminal ganglia (TG) neurons and showed that estradiol rapidly (15 min) enhances cellular signaling by two inflammatory mediators, bradykinin (BK) and prostaglandin E2 (PGE2) in cultured TG neurons. Our overall hypothesis is that estrogens, acting via rapid signaling pathways, increase the responsiveness of TG nociceptors to stimulation by inflammatory mediators and that this plays a role in the enhanced pain sensitivity of women. Specific Aim 1: Characterize rapid effects of estradiol (17_-E2) on BK and PGE2 signaling in trigeminal ganglion. We will determine the concentration- and time- and ligand-dependence of 17_-E2 action and identify the estrogen receptor that mediates the rapid action using siRNA knock-down. Specific Aim 2: Identify the rapid 17_-E2-induced changes in the BK and PGE2 receptor systems that are responsible for enhancement of signaling in TG cultures. We will determine if the mechanism for the increased signaling efficacy of BK and PGE2 is due to increases in cell-surface receptor density or to changes in signal transduction efficiency (receptor-G protein coupling efficiency or trafficking to/from membrane microdomains (lipid rafts). Specific Aim 3: Determine the effect of 17_-E2 on nociception in an orofacial model of acute inflammation in female rats. We will determine if exogenously applied 17_-E2 in vivo alters nocifensive behavioral responses to BK, PGE2 or to formalin. In addition, we will assess the role of endogenous 17_-E2 during the estrus cycle on orofacial nociception. These integrated studies will increase our understanding of the consequences and the mechanisms by which estrogen, acting via rapid signaling mechanisms, regulates signaling and nociception by the inflammatory mediators BK and PGE2 in the rat trigeminal ganglion. Detailed study of estrogen receptors and their effects on inflammatory mediator signaling in TG will provide a basis for understanding the enhanced sensitivity of women to pain and provide new targets for improved pain pharmacotherapy. Project Narrative Although pain does not discriminate between men and women, epidemiological studies have demonstrated that women are at increased risk for orofacial and other forms of pain. The integrated studies proposed here will increase our understanding of the consequences and the mechanisms of the female sex hormone, estrogen, that regulate responsiveness of sensory neurons to painful stimuli. This work will provide a basis for understanding the enhanced sensitivity of women to pain and provide new targets for improved pain pharmacotherapy.