MECHANISMS FOR THE INTESTINAL PROBIOTIC EFFECTS OF S. BOULARDII

S. Boulardii 的肠道益生菌作用机制

• 批准号: 7022015
• 负责人: Ciaran P Kelly
• 金额: $ 27.71万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-10-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7022015
• 关键词: Clostridium difficile; I kappa B beta; SCID mouse; Saccharomyces; antiinflammatory agents; bacterial toxins; biotherapeutic agent; cytoprotection; enteric bacteria; enzyme activity; epidermal growth factor; gastrointestinal infection; human fetus tissue; inflammation; interleukin 1; laboratory mouse; microorganism interaction; mitogen activated protein kinase; nuclear factor kappa beta; protein tyrosine kinase; tumor necrosis factor alpha; xenotransplantation

Saccharomyces boulardii is a non-pathogenic yeast that has been used safely for many decades to protect against intestinal injury, inflammation and secretion caused by a variety of bacterial enteric pathogens including Ciostridium difficile and Shigellae. The longterm goal of this project is to define specific cellular and molecular mechanisms for the protective and therapeutic effects of probiotic agents such as S. boulardii in intestinal infection and inflammation. The broad-ranging beneficial effects of S. boulardii led us to hypothesize that this probiotic yeast may act through modulation of host intestinal inflammatory response pathways. Our preliminary data demonstrate that S. boulardii produces a soluble factor that prevents IkappaBalpha degradation, NF-kappaB nuclear translocation and NF-kappaB-mediated IL-8 gene expression in human intestinal epithelial cells or monocytes. Purification and characterization studies indicate that the S. boulardii antiinflammatory factor (SAIF) is a small (approximately 1 kDa), heat stable, water soluble glycan. The Specific Aims of this proposal are: Aim 1: To determine the mechanism whereby S. boulardii and SAIF modulate NF-kappaB activation and pro-inflammatory gene expression in monocytes and intestinal epithelial cells exposed to bacterial products (C. difficile toxin A, LPS), or endogenous inflammatory mediators (IL-1betap, TNFalpha). In collaboration with project 1 we will also examine the ability of S. boulardii to modulate NF-kappaB signaling in response to the gut neuropeptides CRH and urocortin II. Aim 2: To determine whether and by which mechanism S. boulardii and SAIF prevent MAP kinase activation and signaling. This aim will also test the hypothesis that S. boulardii blocks Ras/Erk MAP kinase signaling through an inhibitory effect on EGF receptor kinase activation. Aim 3: To elucidate the mechanisms whereby S. boulardii and SAIF augment intestinal epithelial barrier function in polarized T84 monolayers and in murine small intestinal mucosal strips (in collaboration with projects 3 and 4). Aim 4: To determine whether S. boulardii and SAIF can prevent intestinal injury, inflammation and loss of barrier function in both murine and human xenograft intestinal mucosa exposed to C. difficile toxin A (in collaboration with Core B). Examination of these specific aims will advance our understanding of the cellular and in vivo mechanisms whereby a probiotic yeast and/or its soluble products can prevent and treat gastrointestinal infectious and inflammatory diseases in humans.

Saccharomyces boulardii是一种非致病酵母菌，数十年来已被安全地用于防止肠道损伤，炎症和分泌，这是由多种细菌肠道病原体引起的，包括艰难梭菌（Ciostridium costridium and）和志伊尔（Shigellae）。该项目的长期目标是定义特定的细胞和分子机制，用于益生菌在肠道感染和炎症中的保护性和治疗作用。 S. boulardii的广泛有益作用使我们假设该益生菌酵母可能通过调节宿主肠道炎症反应途径而起作用。我们的初步数据表明，S。boulardii产生的可溶性因子可以防止Ikappabalpha 人类肠上皮细胞或单核细胞中的降解，NF-kappab核转运和NF-kappab介导的IL-8基因表达。纯化和表征研究表明，Boulardii抗炎因子（SAIF）是一个小（约1 kDa），热稳定，水溶性聚糖。该提案的具体目的是：目标1：确定单核细胞和暴露于细菌产物的单核细胞和肠上皮细胞中的NF-kappab激活和促炎基因表达的机制（艰难梭菌A，LPS，LPS，LPS） ），或内源性炎症介质（IL-1Betap，tnfalpha）。在 与项目1合作，我们还将研究Boulardii S. boulardii对肠道神经肽CRH和尿素素II调节NF-kappab信号传导的能力。目标2：确定S. boulardii和SAIF是否以及通过哪种机制来防止MAP激酶激活和信号传导。该目标还将检验以下假设：s。boulardii通过对EGF受体激酶激活的抑制作用来阻断Ras/ERK MAP激酶信号传导。目标3：为了阐明偏光T84单层和小鼠小肠粘膜条中的Boulardii和Saif增强肠上皮屏障功能的机制（与项目3和4合作）。目标4：确定s。boulardii和saif是否可以防止肠道损伤，炎症和人类异种移植物肠肠粘膜在暴露于艰难梭菌毒素A（与Core B合作）中。对这些特定目的的检查将提高我们对细胞和体内机制的理解，从而使益生菌酵母和/或它的理解 可溶性产品可以预防和治疗人类胃肠道感染和炎症性疾病。