MECHANISMS OF VISCERAL PAIN DRIVEN BY SMALL INTESTINAL MICROBIOTA

小肠微生物驱动内脏疼痛的机制

• 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
• 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

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.

项目摘要/摘要 肠易激综合症是一种全球流行疾病（〜11％），其特征是粪便改变 每周一日或多天形式/频率和腹痛。 IBS中的腹痛，与其他形式的 内脏疼痛，通常是弥漫性且局部较差的，因此很难描绘病理部位，作为一个 结果几乎没有治疗选择。肠道微生物产品已被证明是重要的腔信号 对于腹痛，但这些研究主要集中在结肠上。我们最近发现小肠 微生物组合物与腹痛等胃肠道（GI）症状有关，但是机制 小肠微生物群/微生物产物在腹痛的病理生理学中的作用 仍然是一个关键的知识差距。为了解决这一差距，我们将阐明近端的感觉神经 小肠并识别小肠检测到的细胞和分子途径 传递有助于内脏超敏反应的腔微生物信号。在我们广泛的初步 研究，我们建立了一个专门的模型，以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和上皮细胞的作用，以及新型的外体脊髓 - 小肠准备工作，以研究通过腔代谢物向脊髓传播向脊髓的传播 通过（1）EC细胞发出信号，是上皮细胞，通过神经递质通过5-羟色胺向神经元发出信号 在调节内脏疼痛的肠道中，以及（2）背根神经节（DRG）的感觉神经元，一阶 疼痛途径的传入神经元。使用这些模型，我们确定了不同的细菌和细菌代谢产物 激活EC细胞和胸腔DRG神经元。根据我们的初步发现，我们假设这很小 肠道细菌产物通过激活小肠感觉传入有助于内脏超敏反应 通过激活EC细胞直接并通过神经上皮连接。我们将在两个中解决该假设 使用尖端刺激/采集方法的具体目的，包括CA2+成像的组合 器官，EC细胞和DRG神经元的电生理学，新型转基因小鼠的体内制剂， 和腺相关病毒（AAV），表征了小肠的感觉输入和光遗传学 研究神经上皮信号传导。在特定目标1中，我们将确定EC激活的基础机制 细胞和DRG神经元，以及在特定的目标2中，我们将确定涉及的感觉转导途径 在响应不同的微生物产品时。这些研究将是第一个提供功能和分子的研究 在DRG中的感觉神经元的表征，该神经支配小肠，确定哪个 亚群被管腔中的微生物产物激活和/或敏化，并测试EC细胞是否为 参与感觉转导途径。我们的发现将允许发展新型微生物 腹痛的疗法，靶向小肠中不同的微生物途径。