Bioelectricity in Gut Epithelium Drives Pathogenic Bacterial Targeting

项目摘要 我们的肠道包含大约100万亿个共生细菌，它们共同促进营养吸收和 免疫系统的成熟，以及在保护宿主免受肠道细菌侵袭方面发挥核心作用 感染。然而，许多肠道细菌病原体已经制定了在肠道定居的策略。 和引起疾病的粘膜。临床上重要的肠道细菌，如沙门氏菌、志贺氏菌、耶尔森氏菌和 致病性大肠埃希氏菌，由于其致病能力可导致严重的 具有潜在致命后果的腹泻和肠外疾病及其传播的简易性 通过受污染的食物和水。这些细菌已经制定了共同的策略，专门针对 并侵袭数量相对较少的毛囊相关上皮(FAE)细胞，称为微皱折(M)细胞 引发炎症。极低剂量的污染，有时只有几种病原体，可以 导致严重的肠炎和/或播散性感染。人们仍然不太清楚为什么这么少的细菌 病原体，通常被数百万(如果不是数十亿)共生微生物包围着，找到了一种方法来 他们的目标入口--FAE的低丰度M细胞。 以前，我们已经证明了气管粘液中存在内源性生物电场。 并首次检测到沙门氏菌感染产生的电 小鼠盲肠FAE.这些生物电信号在胚胎发育过程中起着关键作用。 发育、组织再生和伤口愈合，以及我们所展示的播散性感染 在我们最新的研究中。通过施加模拟IGEF的电场，我们已经证明了共生大肠杆菌 向阳极迁移，致病沙门氏菌向阴极迁移，同时排他性地。 在这个探索性的R21中，我们提出了一种新的病原菌生物电控机制 瞄准目标。我们的中心假设是FAE周围存在一个活跃的上皮性“电池”，即 本质上被细菌病原体利用，用于侵入性靶标。我们将通过以下方式测试我们的假设 具体目标如下：1)在空间上定义和表征肠上皮细胞的生物电活动。vbl.使用 先进的电生理技术，我们将测量和药物操纵离子电流 毛细支气管炎及周围绒毛上皮的密度、跨上皮电位和跨膜电位 小鼠盲肠体外模型。成功完成将建立肠道的第一个生物电学剖面 上皮组织。2)分析肠道上皮细胞生物电在细菌侵袭靶向中的作用机制。我们的 工作假说是肠道病原体利用局部生物电来战略性地以FAE为靶点。 细菌表面的电学性质。这将在体外和实验中进行基因测试和确认。 活着。了解生物电学特性如何引导病原体进入M细胞可以为未来提供信息 预防/治疗胃肠道感染和炎症的药物方法。

Project Summary Our gut contains about 100 trillion commensal bacteria that collectively contribute to nutrient absorption and maturation of the immune system, as well as play a central role in protecting the host from enteric bacterial infections. However, many enteric bacterial pathogens have developed strategies to colonize the intestinal mucosa and cause diseases. Clinically significant enteric bacteria, such as Salmonella, Shigella, Yersinia, and pathogenic E. coli, are a major public health concern due to their pathogenic capacities to cause severe diarrheal and extraintestinal diseases with potentially fatal consequences, and their ease of transmission through contaminated food and water. These bacteria have developed common strategies to specifically target and invade a relatively small number of follicle-associated epithelial (FAE) cells known as Microfold (M) cells to induce inflammation. Contamination with extremely low doses, sometimes with only a few pathogens, can cause severe enteritis and/or disseminated infections. It remains poorly understood how so few bacterial pathogens, which are typically surrounded by millions (if not billions) of commensal microbes, find a way to their targeted portal of entry—the low abundance M cells of the FAE. Previously, we have demonstrated the existence of endogenous bioelectric fields in the tracheal mucus epithelium of the rhesus monkey and, and for the first time, detected Salmonella infection-generated electric fields (IGEF) in mouse cecum FAE. These bioelectrical signals play critical roles during embryonic development, tissue regeneration and wound healing, as well as in disseminated infections as we demonstrate in our most recent work. By applying electric fields mimicking IGEF we have shown that commensal E. coli migrate to the anode and pathogenic Salmonella migrate to the cathode, exclusively and simultaneously. In this exploratory R21, we propose a novel mechanism of bioelectrical control in pathogenic bacterial targeting. Our central hypothesis is that an active epithelial “battery” exists around the FAE, which is intrinsically exploited by bacterial pathogens for invasive targeting. We will test our hypothesis through the following specific aims: 1) Spatially define and characterize bioelectrical activities at gut epithelia. Using advanced electrophysiological techniques, we will measure and pharmacologically manipulate ionic current density, trans-epithelial potential, and transmembrane potential in FAE and surrounding villus epithelium in an ex vivo mouse cecum model. Successful completion will establish the first bioelectricity profile of intestinal epithelium. 2) Dissect the mechanisms of bioelectricity at gut epithelia in bacterial invasive targeting. Our working hypothesis is that enteric pathogens utilize local bioelectricity to strategically target the FAE depending on the surface electrical properties of the bacteria. This will be tested genetically and affirmed in vitro and ex vivo. Understanding how the bioelectric properties guide pathogen entry into M cells could inform future pharmaceutical approaches to prevent/treat gastrointestinal infection and inflammation.