TRPA1: a polymodal sensor for aversive stimuli

描述（由申请人提供）：拟议研究的长期目标是使用果蝇（Drosophila melanogaster）作为动物模型，以揭示昆虫对感觉线索（从温度变化到驱虫剂）作出反应的机制。这些问题可能与控制害虫有关，因为传播疾病的蚊子通过热敏、视觉和化学线索被吸引到人类身边。令人厌恶的温度和化学驱虫剂阻止昆虫。因此，了解回避行为的机制可能为害虫防治提供重要的见解。感受环境刺激的一组关键受体蛋白是瞬时受体电位（TRP）阳离子通道。在果蝇的13个成员中，TRPA 1特别值得注意，因为它是一种检测各种有害感觉输入的检测器，包括轻微的温暖或炎热的温度，驱虫剂和过度的光线。在这里，我们建议解剖的分子，细胞和行为机制，通过TRPA1允许幼虫和成年苍蝇逃避厌恶刺激。为了实现我们的目标，我们建议采用多学科的方法，使用分子遗传学，生物化学，细胞生物学，电生理学和行为方法的组合。目的1将测试的假设，明亮的光，幼虫避免，激活TRPA1通过一种新的光检测机制，是独立的细胞表面蛋白。在目标2中，我们提出了一个假设，即TRPA1作为一个探测器，允许苍蝇使用每天的温度变化来设置运动活动的昼夜节律周期。目标3中提出的实验将测试关于TRPA1通过热敏信号级联激活的功能和机制的假设。这种级联反应代表了一种新的TRP通道激活模式，与众所周知的温度变化直接激活“thermoTRP”相反。目的4是观察到TRPA1是苍蝇避免驱虫剂香茅醛所必需的，并且这种反应在蚊子和果蝇中通过直接和间接机制发生。在这个目标的第一部分，我们将测试的假设，一个额外的TRPA通道功能的厌恶反应，其他驱虫剂（香叶醇和樟脑）。目的4的第二部分测试了G蛋白偶联受体直接检测驱避剂并启动导致TRP通道间接激活的信号级联的假设。拟议的研究最终可能导致识别新一代更安全，更有效的驱虫剂，通过识别和表征此类化合物的分子靶标来控制虫媒疾病。 公共卫生相关性：传播疾病的害虫识别它们的人类宿主，并通过它们检测热、化学和视觉线索的能力来避免有害的环境条件。拟议工作的重点是利用果蝇作为动物模型的巨大技术优势，发现昆虫用于感知环境刺激的分子和机制，长期目标是利用这些见解开发新的策略来控制虫媒疾病的传播。

DESCRIPTION (provided by applicant): The long-term goal of the proposed research is to use the fruit fly, Drosophila melanogaster, as an animal model to unravel the mechanisms through which insects respond to sensory cues, ranging from changes in temperature to insect repellents. These questions are of potential relevance to the control of insect pests, since mosquitoes that spread diseases are attracted to humans through thermosensory, visual and chemical cues. Aversive temperatures and chemical repellents deter insects. Therefore, understanding the mechanisms underlying avoidance behavior may provide important insights into insect pest control. A key group of receptor proteins that sense environmental stimuli are Transient Receptor Potential (TRP) cation channels. Among the 13 Drosophila members, TRPA1 is of particular note as it is a detector for a wide array of noxious sensory inputs, including slightly warm or hot temperatures, insect repellents, and excessive light. Here, we propose to dissect the molecular, cellular and behavioral mechanisms through which TRPA1 allows larvae and adult flies to elude aversive stimuli. To accomplish our goals, we propose to employ a multidisciplinary approach, using a combination of molecular genetics, biochemistry, cell biology, electrophysiology and behavioral approaches. Aim 1 will test the hypothesis that bright light, which larvae avoid, activates TRPA1 through a novel mechanism of light detection that is independent of a cell surface protein. In Aim 2 we propose to test the hypothesis that TRPA1 functions as a detector that allow flies to use the daily changes in temperature to set circadian cycles of locomotor activity. The experiments proposed in Aim 3 will test hypotheses concerning the function and mechanism by which TRPA1 is activated via a thermosensory signaling cascade. This cascade represents a new mode of activation of TRP channels in contrast to the well-known direct activation of "thermoTRPs" by changes in temperature. Aim 4 is an outgrowth of the observation that TRPA1 is required for flies to avoid the insect repellent, citronellal, and this response occurs through both direct and indirect mechanisms in both mosquitoes and fruit flies. In the first part of this aim we will test the hypothesis that an additional TRPA channel functions in the aversive responses to other insect repellents (geraniol and camphor). The second part of aim 4 tests the hypothesis that G-protein coupled receptors detect repellents directly, and initiate signaling cascades that lead to indirect activation of TRP channels. The proposed studies ultimately could lead to the identification of a new generation of safer and more effective repellents to control insect-borne disease by identifying and characterizing molecular targets for such compounds. PUBLIC HEALTH RELEVANCE: Insect pests that spread disease identify their human hosts, and avoid noxious environmental conditions through their ability to detect thermal, chemical and visual cues. The focus of the proposed work is to exploit the great technical advantages of the fruit fly as an animal model to discover molecules and mechanisms that insects use to sense environmental stimuli, with the long-term goal of using these insights to develop new strategies to control the spread of insect-borne disease.