Characterizing neurogenic progenitors in the adult intestine

项目摘要 肠道神经系统(Ens)对人类健康具有重要的调节作用。 胃肠(GI)功能方面，最显著的是肠道动力。先天性或获得性颈椎畸形 因此，ENS会导致严重的功能性胃肠道疾病，包括食道失弛缓症、胃瘫、 肠假性梗阻、肠易激综合征、先天性巨结肠和慢传输型便秘。 众所周知，成人肠道拥有神经前体细胞，但它们的作用和激活机制 他们是未知的。我们和其他人在特定的实验损伤中观察到了新神经元的诞生 模型，包括肠道炎症、胃肠道感染和局部神经元消融后。这是神经性的 反应可以用来替代因损伤而丢失的神经元，但它也会产生神经元增生，这可能 会产生重大的病理后果。因此，肠道神经发生是一把双刃剑，可以 利用杠杆可以产生有益的效果，但需要加以调整，以限制其后果。我们的初步结果 提示啮齿动物实验性结肠炎促进肠神经胶质细胞发生神经源性转化。 5-HT4依赖途径。然而，人们对这一过程知之甚少。这项提案的总体目标是 是了解出生后肠神经发生的潜在机制及其在胃肠道健康和 疾病。为了实现这一目标，我们提出了以下具体目标：(1)确定下游路径 被5-HT4信号激活，并导致神经胶质分化为神经元；(2)表征 神经胶质细胞亚群存在于肠道中，并决定了 发生在神经胶质细胞到神经元的命运转换过程中；以及(3)利用肠道的神经再生能力来治疗 与先天性巨结肠症相关的神经节细胞减少移行区。各种方法论将被 用于实现这些目的，包括分离和培养报告小鼠的肠道神经胶质细胞；体外试验 使用显性-负性突变体和药物抑制剂来确定参与的信号通路 神经胶质细胞发生；单细胞rna序列鉴定神经胶质细胞亚群；双报告转基因系统 用于神经胶质细胞到神经细胞命运转变的活细胞成像；遗传和表观遗传变化的分析 在过渡期间发生；以及在HSCR肠道诱导肠神经发生以治疗过渡区 神经节细胞缺乏症。这些实验的成功完成将大大提高我们对 成人肠道神经发生的潜在机制，为深入了解糖尿病的病理生理学提供了基础。 神经肠道疾病，识别新的靶点来调节体内的神经发生，为 HSCR神经节下移行区和其他神经肠中扩张的肠神经元 并改进肠神经前体细胞的体外扩增，用于细胞治疗应用。

Project Summary The enteric nervous system (ENS) is of fundamental importance to human health through its regulation of all aspects of gastrointestinal (GI) function, most notably gut motility. Congenital or acquired abnormalities of the ENS consequently can lead to serious functional GI disorders, including esophageal achalasia, gastroparesis, intestinal pseudo-obstruction, irritable bowel syndrome, Hirschsprung disease, and slow transit constipation. The adult intestine is known to possess neuronal progenitors, but their role and the mechanisms that activate them are unknown. We and others have observed the birth of new neurons in specific experimental injury models, including intestinal inflammation, GI infection, and following focal neuronal ablation. This neurogenic response can serve to replace neurons lost to injury, but it can also produce neuronal hyperplasia which can have significant pathologic consequences. Enteric neurogenesis is thus a double-edged sword that can be leveraged for a beneficial effect but needs to be modulated to limit its consequences. Our preliminary results suggest that experimental colitis in rodents promotes enteric glial cells to undergo a neurogenic transition via a 5-HT4-dependent pathway. However, this process is poorly understood. The overall objective of this proposal is to understand the mechanisms underlying postnatal enteric neurogenesis and its role in GI health and disease. To achieve this goal, we propose the following specific aims: (1) identify the downstream pathways that are activated by 5-HT4 signaling and lead to glial differentiation into neurons; (2) characterize the subpopulations of glial cells present in the intestine and determine the genetic and epigenetic changes that occur during the glia-to-neuron fate switch; and (3) leverage the intestine’s capacity for neurogenesis to treat the hypoganglionic transition zone associated with Hirschsprung disease. A variety of methodologies will be used to achieve these aims, including isolation and culture of enteric glia from reporter mice; in vitro assays using dominant-negative mutants and pharmacologic inhibitors to determine the signaling pathways involved in glial neurogenesis; single cell RNA seq to identify glial cell subpopulations; a dual reporter transgenic system for live cell imaging of glia-to-neuron cell fate transition; analysis of the genetic and epigenetic changes occurring during that transition; and induction of enteric neurogenesis in HSCR bowel to treat transition zone hypoganglionosis. Successful completion of these experiments will significantly enhance our understanding of the mechanisms underlying neurogenesis in the adult intestine, provide insights into the pathophysiology of neurointestinal diseases, identify new targets to modulate neurogenesis in vivo, offer novel approaches for expanding enteric neurons in the hypoganglionic transition zone of HSCR and in other neurointestinal diseases, and improve the in vitro expansion of enteric neuronal progenitors for cell therapy applications.