Estrogen regulation of inflammatory mediator signaling

描述(由申请者提供)：三叉神经系统的疼痛障碍经常被数百万美国人报告。虽然疼痛不区分男性和女性，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。与男性相比，女性更有可能报告各种暂时性和持续性疼痛，并报告更严重、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(15分钟)可通过两种炎症介质--缓激肽(BK)和前列腺素E_2(PGE_2)迅速增强培养的三叉神经节(TG)神经元的细胞信号。我们的总体假设是，雌激素通过快速信号通路作用，增加TG伤害性感受器对炎症介质刺激的反应性，这在增强女性的疼痛敏感性方面发挥了作用。具体目的1：研究雌激素(17-E_2)对三叉神经节BK和PGE_2信号的快速影响。我们将确定17_-E2作用的浓度、时间和配体的依赖关系，并通过siRNA敲除来确定介导这种快速作用的雌激素受体。具体目标2：确定17-雌二醇诱导的BK和PGE2受体系统的快速变化，这些变化负责增强TG培养中的信号转导。我们将确定BK和PGE2信号有效性增加的机制是由于细胞表面受体密度的增加，还是由于信号转导效率的变化(受体-G蛋白偶联效率或膜微域(脂筏)的转运)。具体目标3：在雌性大鼠口腔颌面部急性炎症模型中，确定17-E_2对伤害性感受的影响。我们将确定在体内外源性应用17_E_2是否改变对BK、PGE_2或福尔马林的致病行为反应。此外，我们还将评估发情周期中内源性17_E_2在口腔面部伤害性感受中的作用。这些综合研究将增加我们对雌激素通过快速信号机制调节炎症介质BK和PGE2在大鼠三叉神经节中的信号传递和伤害性感受的后果和机制的了解。深入研究雌激素受体及其在炎症介质信号转导中的作用，将为了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。项目简介虽然疼痛不歧视男性和女性，但流行病学研究表明，妇女患口腔面部和其他形式疼痛的风险增加。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。这项工作将为了解女性对疼痛的增强敏感性提供基础，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.