Protection from enteric pathogens by beneficial microbes

通过有益微生物预防肠道病原体

• 批准号: 8256331
• 负责人: Katherine L. Knight
• 金额: $ 25.89万
• 依托单位: LOYOLA UNIVERSITY CHICAGO
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-18 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8256331
• 关键词: Affect; Agonist; Anti-Inflammatory Agents; Anti-inflammatory; Attenuated; Bacillus (bacterium); Bacillus licheniformis; Bacillus subtilis; Bacteria; Bioluminescence; C-Type Lectins; CD4 Positive T Lymphocytes; Cells; Child; Citrobacter rodentium; Disease; Dose; Escherichia coli EHEC; Exposure to; Flagellin; Flow Cytometry; Gastrointestinal tract structure; Goals; Grant; Homeostasis; Image; Immune; Immune response; Inflammation; Inflammatory Response; Inflammatory disease of the intestine; Intestines; Knock-out; Knockout Mice; Ligands; Luciferases; Mediating; Mesentery; Microbe; Mus; Natural Immunity; Oral; Peptidoglycan; RIPK2 gene; Receptor Signaling; Regulatory T-Lymphocyte; Reproduction spores; Site; TLR2 gene; TLR5 gene; Testing; Toll-like receptors; commensal microbes; design; enteric pathogen; in vivo; intestinal epithelium; killings; lymph nodes; mutant; pathogen; prevent; receptor; research study

DESCRIPTION (provided by applicant): The host and its commensal microbiota generally maintain a peaceful coexistence; however, a few bacteria disrupt immune homeostasis and cause disease. For example, attaching and effacing (A/E) enteropathogenic and enterohemorrhagic E. coli (EPEC and EHEC) cause diarrheal diseases that affect more than 2 billion people and kill 1.5 million children annually. Commensal bacteria can protect the host from disease caused by enteric pathogens; however, the mechanisms by which this occurs are poorly understood. We recently found that a single oral dose of commensal Bacillus subtilis or Bacillus formis spores can protect mice from disease caused by the A/E pathogen, Citrobacter rodentium. In contrast, a closely related commensal Bacillus licheniformis, and two B. subtilis mutants, hag and espH, did not protect the host. Because the single dose of protective Bacillus spp. is given 24 hr prior to pathogenic C. rodentium, protection is not likely due to initiation of an adaptive immune response, but is more likely due to an innate anti-inflammatory immune response. Alternatively, Bacillus spp. could protect from disease by directly interfering with localization of C. rodentium to the intestinal epithelium. In Aim 1 we will use in vivo bioluminescence imaging (IBIS) to determine if protective Bacillus spp. alter the colonization site of pathogenic C. rodentium. One of the non-protective B. subtilis mutants is deficient in flagellin, a ligand for TLR5, and another is deficient in exopolysaccharide, presumed ligand for TLR2, and in Aim 2 we will use TLR agonists and TLR knockout mice to determine if protection is mediated through TLR. Similarly, we will use Nod-like receptor (NLR) agonists and knockout mice to determine if protection is mediated through NLR. In Aim 3, we will test the possibility that B. subtilis mediates protection through T regulatory cells. PUBLIC HEALTH RELEVANCE: We investigate a means of protecting against enteric pathogens that cause diarrheal disease by a single oral dose of spores from a commensal-like (beneficial) bacterium. The experiments are designed to determine the mechanism by which this protection occurs. We investigate the possibilities that the commensal bacterium interferes with colonization of the enteric pathogen, or stimulates an anti-inflammatory response in the host.

描述（由申请人提供）：宿主与其共生微生物群通常保持和平共处；然而，一些细菌会破坏免疫稳态并导致疾病。例如，附着和消除 (A/E) 肠致病性和肠出血性大肠杆菌（EPEC 和 EHEC）会导致腹泻疾病，影响超过 20 亿人，每年导致 150 万儿童死亡。共生细菌可以保护宿主免受肠道病原体引起的疾病；然而，人们对这种现象发生的机制知之甚少。我们最近发现，单次口服剂量的共生枯草芽孢杆菌或芽孢杆菌孢子可以保护小鼠免受 A/E 病原体、啮齿类柠檬酸杆菌引起的疾病。相比之下，密切相关的共生地衣芽孢杆菌和两种枯草芽孢杆菌突变体 hag 和 espH 并不能保护宿主。因为单剂量的保护性芽孢杆菌属。在致病性啮齿类弯曲杆菌之前 24 小时给予，保护不太可能是由于适应性免疫反应的启动，而更有可能是由于先天抗炎免疫反应。或者，芽孢杆菌属。可以通过直接干扰啮齿类柠檬酸杆菌在肠上皮细胞的定位来预防疾病。在目标 1 中，我们将使用体内生物发光成像 (IBIS) 来确定芽孢杆菌是否具有保护作用。改变致病性啮齿类梭菌的定植位点。其中一种非保护性枯草芽孢杆菌突变体缺乏鞭毛蛋白（TLR5 的配体），另一种则缺乏胞外多糖（推测为 TLR2 的配体），在目标 2 中，我们将使用 TLR 激动剂和 TLR 敲除小鼠来确定保护是否有效。通过 TLR 介导。同样，我们将使用 Nod 样受体 (NLR) 激动剂和基因敲除小鼠来确定 NLR 是否介导保护作用。在目标 3 中，我们将测试枯草芽孢杆菌通过 T 调节细胞介导保护的可能性。 公共卫生相关性：我们研究了一种通过单次口服剂量来自类共生（有益）细菌的孢子来预防引起腹泻病的肠道病原体的方法。这些实验旨在确定这种保护发生的机制。我们研究了共生细菌干扰肠道病原体定植或刺激宿主抗炎反应的可能性。