TRPA1 Channels in Sensory Neurons as Targets for Environmental Irritants

描述(由申请人提供)： 我们研究的长期目标是揭示有害环境刺激物激活感觉神经的分子和细胞基础。肺、皮肤、眼睛和粘膜中的感觉神经末梢被环境毒物激活，包括α，β-不饱和醛。醛，如丙烯醛(2-丙二醛)，是存在于香烟烟雾、火灾烟雾、汽车尾气和烟雾中的严重刺激性挥发性化合物。在人类中，丙烯醛暴露与急性肺损伤、化学超敏反应、慢性肺阻塞性疾病(COPD)和哮喘的发病机制有关。尽管丙烯醛和其他环境刺激物对人类暴露的健康影响具有重要作用，但其对感觉神经元的分子靶点仍不清楚。 在这里，我们建议识别和表征丙烯醛和其他环境刺激物在体感神经元上的分子靶点。我们的具体目标来自我们的初步数据，这些数据表明，丙烯醛和一种不同类别的刺激物异氰酸酯通过刺激钙离子通过离子通道TRPA1内流来激活神经元。TRPA1最近通过其对异硫氰酸烯丙酯(芥子油)的敏感性而被鉴定，异硫氰酸烯丙酯是一种用于探测疼痛传导通路的刺激物。我们发现，TRPA1仅在对辣椒素敏感的感觉纤维中表达，辣椒素是一种植物来源的刺激物，激活辣椒素受体TRPV1。这些感觉纤维，即C-纤维，被认为是介导刺激效应和炎性疼痛的媒介。 我们的应用目的是调查TRPA1是否是丙烯醛和其他环境暴露在体内的急性和长期刺激性影响的潜在原因。我们的具体目标是：1)研究TRPA1基因缺陷小鼠对丙烯醛的感觉神经反应；2)阐明TRPA1的激活和炎症增敏机制；3)研究和比较工业异氰酸酯对感觉神经活性的影响；4)检测有害环境毒物对感觉神经活性和感觉神经受体的影响。我们的实验方法将包括转基因小鼠的产生和分析、神经功能的显微成像、电生理技术以及遗传和生化方法。

DESCRIPTION (provided by applicant): The long term goal of our research is to reveal the molecular and cellular basis of sensory neural activation by hazardous environmental irritants. Sensory nerve endings in the lung, skin, eyes and mucous membranes are activated by environmental toxicants, including the alpha, beta-unsaturated aldehydes. Aldehydes such as acrolein (2-propenal) are severely irritating volatile compounds present in cigarette smoke, smoke from fires, automobile exhaust, and smog. In humans, acrolein exposure has been implicated in the pathogenesis of acute lung injury, chemical hypersensitivity, chronic pulmonary obstructive disease (COPD), and asthma. Despite its important role in human exposure health effects, the molecular targets of acrolein and other environmental irritants on sensory neurons remain unknown. Here, we propose to identify and characterize the molecular targets for acrolein and other environmental irritants on somatosensory neurons. Our specific aims are derived from our preliminary data that show that acrolein, and a different class of irritants, the isocyanates, activate neurons by stimulating Ca2+ influx through the ion channel TRPA1. TRPA1 recently has been identified through its sensitivity to allyl isothiocyanate (mustard oil), an irritant used to probe pain transduction pathways. We found that TRPA1 is exclusively expressed in sensory fibers that are also sensitive to capsaicin, the plant-derived irritant that activates the capsaicin receptor, TRPV1. These sensory fibers, the C-fibers, are known to mediate irritant effects and inflammatory pain. The objective of our application is to investigate whether TRPA1 is underlying acute and long-term irritant effects of acrolein and other environmental exposures in vivo. Our specific aims are to 1) investigate sensory neural responses to acrolein in TRPA1-deficient mice, 2) to elucidate the mechanism of activation and inflammatory sensitization of TRPA1, 3) study and compare the effects of industrial isocyanates on sensory neural activity, and 4) examine the effects of hazardous environmental toxicants on sensory neural activity and sensory neural receptors. Our experimental approaches will include the generation and analysis of transgenic mice, microscopic imaging of neural function, electrophysiological techniques and genetic and biochemical approaches.