Molecular mechanisms of sensory transduction in the gut

项目概要 专门的感觉器官包含功能专用的细胞类型，可以检测相关刺激并传递信息 向神经系统传递信息。在这个提案中，我们询问这个概念是否也适用于肠道上皮， 它构成人体最大的暴露表面积之一，并与多种接触 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产生的代谢物。 尽管人们对肠道神经轴的兴趣日益浓厚，但人们对分子机制知之甚少 肠道上皮的潜在化学感应转导，或者该信息如何传递到 神经系统。血清素能肠嗜铬细胞 (EC) 很罕见，但却是肠道内高度特化的实体 上皮细胞与内脏疼痛有关，但由于部分原因而未能详细描述 他们的匮乏。为了规避这些限制，我们从转基因小鼠中产生了肠道类器官 哪些 EC 细胞标有荧光团，使我们能够对这些细胞进行详细的单细胞分析 细胞处于天然组织环境中。我们的初步数据表明这些电池是电的 肠道的可兴奋的多模式化学感应检测器与直接突触相互作用 感觉神经纤维传递有关肠道状态的信息。在这些拟议的研究中，我们将定义 EC 细胞固有的电生理特性、化学感应转导机制和血清素 释放机制（目标 1）并利用此信息研究 EC 激活的生理效应 和相关的神经通路（目标 2）。最后，我们将获得 EC 细胞的遗传途径并使用 化学遗传学工具来检查它们对内脏疼痛的影响（目标 3）。这项工作将阐明 EC 细胞 化学感应机制并检查其在内脏疼痛中的作用，为化学感应机制提供机制基础 了解肠道上皮如何与神经系统沟通。这个分子基础是 对于揭示导致内脏疼痛疾病的病理生理学的基本机制至关重要， 例如肠易激综合症。 该奖项提议的实验方法结合了我在细胞生理学和生物物理学方面的专业知识 通过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。独特的导师团队，在信号方面拥有丰富的经验 转导、疼痛、突触生理学和胃肠道生理学将提供专家指导和理想的 拟议的科学和专业发展的环境。因此，该奖项支持的培训 对于在神经科学和神经科学领域建立独特且重要的独立研究计划至关重要 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.