MECHANISMS OF VISCERAL PAIN DRIVEN BY SMALL INTESTINAL MICROBIOTA

小肠微生物驱动内脏疼痛的机制

基本信息

批准号：
10836298
负责人：
Arthur Beyder
金额：
$ 79.51万
依托单位：
MAYO CLINIC ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-09-19 至 2028-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10836298
关键词：
16S ribosomal RNA sequencing Abdomen Abdominal Pain Acetates Acute Address Affect Afferent Neurons Animal Model Bacteria Cell model Central Nervous System Chemicals Chest Chronic Colon Data Dedications Dependovirus Development Diagnostic Diffuse Disease Disease remission Economic Burden Electrophysiology (science)Enterobacter Enterobacteriaceae Enterochromaffin Cells Epithelial Cells Exposure to Feces Frequencies Functional disorder Germ-Free Growth Health Care Costs Human Hypersensitivity Image Individual Irritable Bowel Syndrome Klebsiella pneumoniae Knowledge Mechanics Modeling Molecular Mus Nature Neuroepithelial Neurons Neurotransmitters Organoids Outcome Pain Pathology Pathway interactions Patients Physiological Population Preparation Probiotics Quality of life Relapse Role Sampling Sensory Serotonin Signal Transduction Site Small Intestines Spinal Cord Spinal Ganglia Stimulus Structure Symptoms Testing Therapeutic Transducers Transgenic Mice Tyrosine Visceral Visceral pain colon bacteria design effective therapy ganglion cell gastrointestinal symptom genome sequencing gut microbiome gut microbiota mechanical stimulus microbial microbial composition microbial products microbiome nerve supply neural neurotransmitter release new therapeutic target novel novel strategies optogenetics productivity loss response sensory input testing access tool transmission process whole genome

项目摘要

PROJECT SUMMARY/ABSTRACT Irritable bowel syndrome is a globally prevalent disorder (~11%) characterized by an alteration in stool form/frequency and abdominal pain one or more days per week. Abdominal pain in IBS, like other forms of visceral pain, is often diffuse and poorly localized, making it difficult to delineate the site of pathology, and as a result there are few therapeutic options. Gut microbial products have been shown to be important luminal signals for abdominal pain, but these studies have largely focused on the colon. We recently found that small intestinal microbial composition is associated with gastrointestinal (GI) symptoms like abdominal pain, but the mechanisms underlying the role of small intestinal microbiota/microbial products in the pathophysiology of abdominal pain remains a critical knowledge gap. To address this gap, we will elucidate the sensory innervation of the proximal small intestine and identify the cellular and molecular pathways by which the small intestine detects and transduces luminal microbial signals that contribute to visceral hypersensitivity. In our extensive preliminary studies, we established a dedicated model to study the physiologic effects of human small intestinal microbiome in germ free (GF) mice, metabolite effects on isolated DRGs and epithelial cells, and a novel ex vivo spinal cord- small intestine preparation to study the transmission of luminal signals to the spinal cord via luminal metabolite signaling through (1) EC cells, that are epithelial cells which signal to neurons via serotonin, a neurotransmitter in the gut that modulates visceral pain, and (2) sensory neurons in dorsal root ganglia (DRG), the first-order afferent neurons of pain pathways. Using these models, we identified distinct bacteria and bacterial metabolites that activate EC cells and thoracic DRG neurons. Based on our preliminary findings, we hypothesize that small intestinal bacterial products contribute to visceral hypersensitivity by activating small intestine sensory afferents directly and through neuro-epithelial connections by activating EC cells. We will address the hypothesis in two Specific Aims using cutting-edge stimulation/acquisition approaches, including combination of Ca2+ imaging in organoids, electrophysiology of EC cells and DRG neurons, ex vivo preparations from novel transgenic mice, and adeno-associated viruses (AAVs) characterizing the sensory input from the small intestine, and optogenetics to study neuro-epithelial signaling. In Specific Aim 1, we will determine mechanisms underlying activation of EC cells and DRG neurons, and in Specific Aim 2, we will determine the sensory transduction pathways involved in responding to distinct microbial products. These studies will be the first to provide a functional and molecular characterization of sensory neurons in the DRG that innervate the small intestine, determine which subpopulations are activated and/or sensitized by microbial products in the lumen, and test whether EC cells are involved in the sensory transduction pathway. Our findings will allow the development of novel microbial therapies for abdominal pain that target distinct microbial pathways in the small intestine.

项目概要/摘要肠易激综合症是一种全球流行的疾病（~11%），其特征是粪便改变每周一天或多天的形式/频率和腹痛。与其他形式的肠易激综合症一样，肠易激综合症也会出现腹痛内脏疼痛通常是弥漫性的且定位不明确，因此很难描绘病理部位，并且作为一种结果，治疗选择很少。肠道微生物产物已被证明是重要的腔信号腹痛，但这些研究主要集中在结肠上。我们最近发现小肠微生物组成与腹痛等胃肠道 (GI) 症状有关，但其机制小肠微生物群/微生物产品在腹痛病理生理学中的作用仍然是一个关键的知识差距。为了解决这个差距，我们将阐明近端的感觉神经支配小肠并确定小肠检测和识别的细胞和分子途径转导导致内脏过敏的腔内微生物信号。在我们广泛的初步研究中，我们建立了一个专门的模型来研究人类小肠微生物组的生理效应在无菌（GF）小鼠中，代谢物对分离的 DRG 和上皮细胞的影响，以及一种新型的离体脊髓小肠准备研究通过管腔代谢物向脊髓传输管腔信号通过 (1) EC 细胞发出信号，这些上皮细胞通过血清素（一种神经递质）向神经元发出信号肠道中调节内脏疼痛的神经元，以及 (2) 背根神经节 (DRG) 中的感觉神经元，一阶疼痛通路的传入神经元。使用这些模型，我们鉴定了不同的细菌和细菌代谢物激活 EC 细胞和胸部 DRG 神经元。根据我们的初步发现，我们假设小肠道细菌产物通过激活小肠感觉传入导致内脏过敏直接或通过激活 EC 细胞通过神经上皮连接。我们将分两部分讨论这个假设使用尖端刺激/采集方法的具体目标，包括结合 Ca2+ 成像类器官、EC 细胞和 DRG 神经元的电生理学、新型转基因小鼠的离体制剂、和腺相关病毒（AAV）表征小肠的感觉输入，以及光遗传学研究神经上皮信号传导。在具体目标 1 中，我们将确定 EC 激活的机制细胞和 DRG 神经元，在具体目标 2 中，我们将确定所涉及的感觉转导途径对不同的微生物产品做出反应。这些研究将是第一个提供功能和分子支配小肠的 DRG 中感觉神经元的特征，确定哪些亚群被管腔中的微生物产物激活和/或致敏，并测试 EC 细胞是否参与感觉转导途径。我们的发现将有助于开发新型微生物针对小肠中不同微生物途径的腹痛疗法。