Molecular mechanisms of sensory transduction in the gut

项目摘要 专门的感觉器官包含功能专用的细胞类型，检测相关刺激并传递 信息传递到神经系统。在这个提议中，我们问这个概念是否也适用于肠道上皮， 其构成人体最大的暴露表面积之一， 化学环境。事实上，肠腔中的许多化学变化与 内脏疼痛，包括刺激物、内源性炎症分子和微生物群产生的代谢物。 尽管对肠神经轴的兴趣越来越大，但对分子机制的了解相对较少 肠道上皮细胞的潜在化学感受转导，或者这种信息如何传递到 神经系统血清素能肠嗜铬细胞（EC）是罕见的，但在肠道内高度专业化的实体 与内脏疼痛有关的上皮，但由于部分原因， 他们的匮乏。为了克服这些限制，我们从转基因小鼠中产生了肠类器官， EC细胞用荧光团标记，使我们能够对这些细胞进行详细的单细胞分析。 在天然组织环境的背景下的细胞。我们的初步数据显示，这些细胞 肠道的可兴奋的多模态化学感受探测器，参与直接突触相互作用， 感觉神经纤维来传递有关肠道状态的信息。在这些研究中，我们将定义 内在EC细胞电生理特性、化学感受性转导机制和5-羟色胺 释放机制（目的1），并利用这些信息来研究EC激活的生理效应 和相关的神经通路（目的2）。最后，我们将获得EC细胞的遗传通路并使用 化学遗传学工具，以检查其对内脏疼痛的贡献（目的3）。这项工作将阐明EC细胞 化学感觉机制，并检查它们在内脏疼痛中的作用，为 了解肠道上皮细胞如何与神经系统沟通。这种分子基础是 对于揭示导致内脏疼痛障碍的病理生理学的基本机制至关重要， 例如肠易激综合征。 为这个奖项提出的实验方法联合收割机结合了我在细胞生理学和生物物理学方面的专业知识 在遗传学和胃肠道生理学方面的新培训，使我能够解决重要的生物学问题， 确定新的分子机制。一个独特的导师团队，在信号方面拥有丰富的经验 传导，疼痛，突触生理学和GI生理学将提供专家指导和理想的 为拟议的科学和专业发展提供环境。因此，该奖项所支持的培训 将是至关重要的，以建立一个独特的和重要的独立的研究计划，在神经科学和 胃肠生理学

Project Summary Specialized sensory organs contain functionally dedicated cell types that detect relevant stimuli and relay information to the nervous system. In this proposal, we ask if this concept also pertains to the gut epithelium, which constitutes one of the largest exposed surface areas of the human body and is in contact with a diverse chemical environment. Indeed, numerous chemical changes in the gut lumen have been associated with visceral pain, including irritants, endogenous inflammatory molecules, and microbiota-produced metabolites. Despite growing interest in the gut-neural axis, relatively little is known about molecular mechanisms underlying chemosensory transduction by the gut epithelium, or how this information is transmitted to the nervous system. Serotonergic enterochromaffin (EC) cells are rare, but highly specialized entities within the gut epithelium that have been implicated in visceral pain but have eluded detailed characterization due, in part, to their paucity. To circumvent these limitations, we generated intestinal organoids from a transgenic mouse in which EC cells are marked with a fluorophore, enabling us to carry out detailed single-cell profiling of these cells in the context of a native tissue environment. Our preliminary data show that these cells are electrically excitable, polymodal chemosensory detectors of the gut that engage in direct synaptic interactions with sensory nerve fibers to transduce information about intestinal state. In these proposed studies, we will define intrinsic EC cell electrophysiological properties, chemosensory transduction mechanisms, and serotonin release mechanisms (Aim 1) and utilize this information to investigate the physiological effects of EC activation on and associated neural pathways (Aim 2). Finally, we will obtain genetic access to EC cells and use chemogenetic tools to examine their contribution to visceral pain (Aim 3). This work will elucidate EC cell chemosensory mechanisms and examine their role in visceral pain to provide a mechanistic foundation for understanding how the gut epithelium communicates with the nervous system. This molecular foundation is critical for uncovering basic mechanisms that contribute to pathophysiology underlying visceral pain disorders, such as irritable bowel syndrome. Proposed experimental approaches for this award combine my expertise in cellular physiology and biophysics with new training in genetics and GI physiology, allowing me to address significant biological questions and identify novel molecular mechanisms. A unique mentorship team with extensive experience in signal transduction, pain, synaptic physiology, and GI physiology will provide expert guidance and an ideal environment for proposed scientific and professional development. Thus, the training supported by this award will be critical to establishing a unique and important independent research program in neuroscience and gastrointestinal physiology.