Neuroregeneration in the Enteric Nervous System

肠神经系统的神经再生

• 批准号: 8937180
• 负责人: David R. Linden
• 金额: $ 35.78万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2018-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8937180
• 关键词: Achalasia; Affect; Animal Model; Automobile Driving; Benzalkonium Chloride; Cells; Chagas Disease; Chronic; Congenital Megacolon; Constipation; Data; Digestive System Disorders; Disease; Dose; Enteral; Enteric Nervous System; Gastrointestinal tract structure; Gastroparesis; Genes; Genetic; Glial Fibrillary Acidic Protein; Goals; Growth; Homeobox; Human; Hybrids; In Vitro; Inflammatory Response; Injury; Intervention; Intestinal Pseudo-Obstruction; Intestines; Life; Mediating; Medical; Modeling; Molecular; Molecular Target; Mouse Strains; Mus; Myenteric Plexus; Natural regeneration; Nerve Regeneration; Neural Crest; Neural Crest Cell; Neuroglia; Neuronal Injury; Neurons; Neuropathy; Operative Surgical Procedures; Pathogenesis; Play; Proteins; RE1-silencing transcription factor; Repression; Signal Pathway; Small Intestines; Source; Stem cells; Structure; Symptoms; Testing; Therapeutic; Transgenic Mice; base; bone morphogenic protein; gliogenesis; insight; meetings; nerve supply; neuron loss; novel; novel therapeutic intervention; public health relevance; relating to nervous system; research study; therapy development; transcription factor; transdifferentiation

 DESCRIPTION (provided by applicant): The overall goal of these studies is to understand the mechanisms of enteric neuroregeneration in order to develop therapies targeted toward endogenous repopulation of the enteric nervous system (ENS) for the treatment of enteric neuropathy. Enteric neuropathy, which contribute to numerous digestive diseases including idiopathic gastroparesis, chronic intestinal pseudoobstruction (CIPO) Hirshsprung's disease, Chagas' disease, achalasia, and possibly slow transit constipation, are characterized by damage or loss of enteric neurons. Existing animal models of enteric neuropathy, i.e., genetic aganglionosis are characterized by complete loss of neural crest cells including neurons and glia. This complete loss, while recapitulating severe congenital human enteric neuropathy, is in contrast to most enteric neuropathy in humans, which are characterized by less severe neuronal loss, and importantly essentially precludes endogenous neural regeneration by neural crest precursors. Overcoming this limitation, we developed a novel low-dose, instead of the traditional high-dose, benzalkonium chloride (BAC) model in the murine small intestine to induce a loss of 50% of neurons, and robust neuroregeneration. It is the only animal model to date that demonstrates robust endogenous neuroregeneration. Using this model with novel transgenic mouse strains and additional in vitro approaches, we will test the overall hypothesis that regeneration of the myenteric plexus is mediated by transdifferentiation of enteric glia to neurons via a SRY-related homeobox transcription factor 2 (SOX2)- dependent mechanism. Our overall hypothesis will be tested by experiments directed at two specific aims. Specific Aim 1 will determine the source and functionality of new neurons following BAC treatment because currently, the cellular origin and function of regenerating neurons are not understood. This aim will be met by testing three hypotheses: 1.1) new neurons derive from enteric cells that express glial fibrillary acidic protein (GFAP); 1.2) glia directly transdifferentiate into neurons; and 1.3 neurons derived from enteric glia are functional and diverse. Enteric glia as a manipulable endogenous source of enteric neurons would be a significant advance because glia outnumber neurons 4:1 in the ENS and are continually replenished by constitutive gliogenesis. Specific Aim 2 will determine the signaling pathways that contribute to enteric neuroregeneration. This aim will be met by testing three hypotheses: 2.1) SOX2 expression in glia is necessary and sufficient to generate new neurons; 2.2) bone morphogenic protein 2 (BMP2) induces SOX2 expression in enteric glial cells; and 2.3) SOX2 reprograms enteric glia to neurons by removing RE1-silencing transcription factor (REST)-mediated repression of neural genes. Results of the proposed studies, involving morphological and molecular characterization of novel transgenic mouse strains for genetic lineage tracing, clonal analysis, and molecular targeting, will provide a mechanistic understanding of enteric neuroregeneration and provide the basis for novel therapeutic approaches for the treatment of enteric neuropathy.

 描述（由申请人提供）：这些研究的总体目标是了解肠神经再生的机制，以便开发肠神经系统（ENS）内源性再生的疗法，用于治疗肠神经病，这有助于肠神经病。许多消化系统疾病，包括特发性胃轻瘫、慢性假性肠梗阻 (CIPO)、先天性巨结肠、恰加斯病、贲门失弛缓症，以及可能的慢传输肠神经病（即遗传性无神经节细胞病）的现有动物模型的特征是神经嵴细胞（包括神经元和神经胶质细胞）的完全丧失，这种完全丧失同时再现了严重的先天性人类肠神经病。与大多数人类肠神经病相反，其特征是神经损失较轻，并且重要的是基本上阻止了神经嵴前体的内源性神经再生，克服了这一限制。我们在小鼠小肠中开发了一种新型低剂量苯扎氯铵 (BAC) 模型，而不是传统的高剂量，可诱导 50% 的神经元损失，并且是迄今为止唯一的动物模型。使用该模型与新型转基因小鼠品系和其他体外方法，证明了强大的内源性神经再生，我们将测试肌间丛再生是由肠神经胶质细胞转分化介导的总体假设。我们的总体假设将通过针对两个特定目标的实验进行测试，具体目标 1 将确定 BAC 治疗后新神经元的来源和功能，因为目前，再生神经元的细胞起源和功能尚不清楚，这一目标将通过测试三个假设来实现：1.1）新神经元源自表达神经胶质纤维酸性蛋白（GFAP）的肠细胞；神经胶质细胞直接转分化为神经元；并且 1.3 源自肠神经胶质细胞的神经元具有功能性和多样性，作为肠神经元的可操纵的内源性来源将是一个重大进步，因为神经胶质细胞在 ENS 中的数量比神经元多 4:1，并且通过组成性胶质细胞生成不断补充。具体目标 2 将确定有助于肠神经再生的信号通路。该目标将通过测试三个假设来实现：2.1）神经胶质细胞中的 SOX2 表达。对于产生新的神经元是必要且充分的；2.2) 骨形态发生蛋白 2 (BMP2) 诱导肠胶质细胞中 SOX2 的表达；2.3) SOX2 通过消除 RE1 沉默转录因子 (REST) 介导的神经元抑制，将肠胶质细胞重新编程为神经元。拟议研究的结果，包括用于遗传谱系追踪、克隆分析和分子靶向的新型转基因小鼠品系的形态和分子特征，将提供 对肠神经再生的机制理解，并为治疗肠神经病的新治疗方法提供基础。