Estrogen regulation of inflammatory mediator signaling

描述（由申请人提供）：三叉神经系统疼痛障碍是数百万美国人经常报告的。虽然疼痛在男女之间没有区别，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更高。女性更有可能报告各种暂时和持续的疼痛，并且报告更严重的疼痛，更频繁的疼痛和持续时间更长。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。我们的初步研究在大鼠三叉神经节（TG）神经元中发现了雌激素受体1 (ER1)，并表明雌二醇在培养的TG神经元中迅速（15分钟）增强了两种炎症介质——缓激肽（BK）和前列腺素E2 （PGE2）的细胞信号传导。我们的总体假设是，雌激素通过快速信号通路，增加TG伤害感受器对炎症介质刺激的反应性，这在增强女性疼痛敏感性中起作用。特异性目的1：表征雌二醇（17_e2）对三叉神经节BK和PGE2信号传导的快速影响。我们将确定17_e2作用的浓度、时间和配体依赖性，并确定通过siRNA敲除介导快速作用的雌激素受体。具体目标2：确定17_e2诱导的BK和PGE2受体系统的快速变化，这些变化负责TG培养中信号的增强。我们将确定BK和PGE2信号传导效率增加的机制是由于细胞表面受体密度的增加还是信号转导效率（受体- g蛋白偶联效率或进出膜微域（脂筏）的运输）的变化。目的3：研究17_e2对雌性大鼠急性炎症损伤感觉的影响。我们将确定在体内外源性应用17_e2是否会改变对BK、PGE2或福尔马林的有害行为反应。此外，我们将评估内源性17_e2在发情周期中对口面部伤害感觉的作用。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炎症介质BK和PGE2信号传导和伤害感受的后果和机制的理解。深入研究雌激素受体及其对TG炎症介质信号传导的影响，将为理解女性疼痛敏感性增强提供基础，并为改进疼痛药物治疗提供新的靶点。虽然疼痛在男性和女性之间没有区别，但流行病学研究表明，女性患口腔面部疼痛和其他形式疼痛的风险更高。这里提出的综合研究将增加我们对女性性激素（雌激素）的后果和机制的理解，雌激素调节感觉神经元对疼痛刺激的反应。这项工作将为理解女性对疼痛的敏感性增强提供基础，并为改进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.