SIGNALING IN TASTE CELLS

描述（由申请人提供）：最近的研究结果表明，味蕾比以前更复杂。成熟的味觉细胞表现出不同的特性，并且可以在它们之间进行交流。有人认为，味觉感受器的化学感觉检测之后是味蕾内感觉信号的成形，然后再传递到大脑，就像其他感觉系统一样。然而，味蕾内细胞异质性和细胞间信号的重要性仍有待解释。我们将提出以下问题，重点是味蕾中最普遍的细胞，胶质样I型细胞：1。I型味觉细胞调节味蕾中的离子环境吗？空间缓冲K+是CNS中星形胶质细胞的关键功能。我们的数据表明，ROMK和某些其他顶端通道可能形成这样的K+清除途径在味蕾。我们将使用共聚焦钙成像的舌片，传入神经记录和行为测定的味蕾，以测试K+积累的影响，使用生理，药理学和遗传操作的ROMK和其他监管机构的K+外流。2. I型味觉细胞使用GABA作为胶质递质来调节味觉信号吗？我们的试验数据表明，I型细胞是味蕾中GABA能回路的关键参与者。我们将完成一种独特的转基因小鼠品系的生产，其中黄色荧光蛋白（YFP）仅在味蕾的I型细胞中表达。然后，我们将使用这些和我们的其他转基因小鼠，以确定受体的细胞类型选择性模式和共聚焦Ca 2+成像分析GABA介导的反应，在这些细胞类型，特别是在味觉诱发反应的影响。3. I型细胞是从局部上皮细胞产生的吗？它们的寿命是多少？味蕾细胞的平均寿命估计为10-14天。早期的研究并不能确定味觉细胞的类型。我们将采用一种新的细胞出生日期技术来评估不同的味觉细胞类型是否具有不同的寿命和谱系。 通过这一系列可验证的假设和专注于I型味蕾细胞的强大新技术，我们将开始解决一个更大的、几十年前的问题：为什么化学感觉味觉细胞形成群落（即味蕾）？味蕾内处理什么信号，细胞之间正在进行的通信在味觉接收中起什么作用？ 公共卫生相关性：味蕾通过口腔中味蕾中不同类型细胞的协调作用来检测营养物质和潜在的有毒物质。我们将研究位于味蕾中但类似于神经胶质的细胞如何影响味蕾的敏感性。由于负责调节的蛋白质位于可接近的位置，因此了解这些机制引入了对厌恶和食欲味觉进行药理学操纵的可能性。

DESCRIPTION (provided by applicant): Recent findings indicate that taste buds are much more complex than previously held. Mature taste cells display diverse properties and may communicate among themselves. There are suggestions that chemo-sensory detection by taste receptors is followed by a shaping of the sensory signal within the taste bud prior to transmission to the brain, much as occurs in other sensory system. Yet, the significance of cellular heterogeneity and intercellular signals within the taste bud remain to be explained. We will ask the following questions focused on the most prevalent cells in taste buds, the glial-like Type I cells: 1. Do Type I taste cells regulate the ionic environment in taste buds? Spatially buffering K+ is a key function performed by astrocytes in the CNS. Our data suggest that ROMK and certain other apical channels may form such a K+ clearance pathway in taste buds. We will use confocal Ca imaging of taste buds in lingual slices, afferent nerve recordings and behavioral assays to test the effects of K+ accumulation using physiological, pharmacological, and genetic manipulations of ROMK and other regulators of K+ efflux. 2. Do Type I taste cells use GABA as a gliotransmitter to modulate taste signals? Our pilot data suggest that Type I cells are key players in GABAergic circuits in taste buds. We will complete production of a unique transgenic mouse strain in which yellow fluorescent protein (YFP) is expressed only in Type I cells of taste buds. We will then use these and our other transgenic mice to identify the cell-type selective pattern of receptors and confocal Ca2+ imaging to analyze GABA-mediated responses in these cells types, especially with respect to the impact on taste-evoked responses. 3. Do Type I cells arise from local epithelium and what is their lifespan? Cells in taste buds have an estimated average lifespan of 10-14 days. Earlier studies did not confidently resolve taste cell types. We will employ a new technology for birth-dating cells to assess if the different taste cell types have different lifespans and lineages. Through this series of testable hypotheses and powerful new technologies focused on Type I taste bud cells, we will begin to address the larger, and decades-old question: why do chemosensory taste cells form communities (i.e. taste buds)? What signals are processed within taste buds and what role in taste reception does ongoing communication among the cells serve? PUBLIC HEALTH RELEVANCE: Taste buds detect nutritive and potentially poisonous materials through the coordinated action of distinct types of cells housed in taste buds throughout the oral cavity. We will investigate how cells located in taste buds, but resembling glia, may influence the sensitivity of taste buds. Because the proteins responsible for regulation are in an accessible location, understanding these mechanisms introduces the possibility of pharmacological manipulation of aversive and appetitive taste sensations.