Shiga toxin 1:uptake mechanisms and intracellular action

志贺毒素 1：摄取机制和细胞内作用

• 批准号: 6799566
• 负责人: OLGA KOVBASNJUK
• 金额: $ 24.85万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-15 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6799566
• 关键词: apical membrane; apoptosis; bacteria infection mechanism; bacterial proteins; bioterrorism /chemical warfare; cytotoxicity; fluorescence microscopy; gastrointestinal epithelium; immunoprecipitation; laboratory rabbit; nucleolus; protein structure function; saxitoxin; shiga toxin; tissue /cell culture

DESCRIPTION (provided by applicant): Foodborne diarrheal disease cause 76,000,000 cases each year in the United States. Intestinal pathology caused by Shiga toxin-producing Escherichia coli (EHEC), important food-borne pathogens, includes approximately 35% of all bloody diarrhea in the United States, an unknown % of watery diarrhea, and the life-threatening systemic manifestations (observed in up to 10% of cases) of infection, the hemolytic uremic syndrome (HUS) and encephalopathy. EHEC are the leading cause currently of acute and chronic renal failure in children in the USA. EHEC is a particularly worrisome foodborne pathogen, because the number of outbreaks caused by EHEC continue to significantly increase and there is no effective specific therapy for this illness which is lethal in up to 10% of children who develop HUS. Thus, there is a great need to better understand the pathogenesis of this infection to promote development of new therapeutic approaches to treat EHEC infection and its complications. Understanding the complex mechanism of Stx uptake and trafficking pathways into colonic epithelium may help to identify new drug targets and develop new strategies directed at preventing toxin action on human intestine. In this application we will study the mechanism of Stx1 and its B-subunit (Stx1B) uptake, trafficking and intracellular action using animal and human intestinal epithelial cell models. In Aim 1 we will study the role of lipid rafts (LR) in Stx1/Stx1B translocation across the apical cell surface. We propose to test the role of LR proteins, which are associated with toxin receptor in toxin translocation machinery. In Aim 2 we will study a newly recognized Stx1/Stx1B internalization pathway from plasma membrane into the nucleoli. In Aim 3 we will study the mechanisms of Stx1/Stx1B-induced apoptosis and its role in toxin-related intestinal inflammation. These proposed studies should provide new insight into the understanding of the molecular basis of Stx-mediated intestinal epithelial cell injury and facilitate the design of strategies to prevent Stx1 uptake and intracellular action, and thus serve to find new targets to interfere with EHEC-related gastrointestinal pathophysiology.

描述（由申请人提供）：在美国，食源性腹泻病每年导致 76,000,000 例病例。由产生志贺毒素的大肠杆菌 (EHEC) 引起的肠道病理学是一种重要的食源性病原体，约占美国所有血性腹泻的 35%，水样腹泻的百分比未知，以及感染导致的危及生命的全身表现（在高达 10% 的病例中观察到）、溶血性尿毒症综合征 (HUS) 和 脑病。肠出血性大肠杆菌是目前美国儿童急性和慢性肾衰竭的主要原因。肠出血性大肠杆菌是一种特别令人担忧的食源性病原体，因为肠出血性大肠杆菌引起的疫情数量持续显着增加，而且目前还没有针对这种疾病的有效特异性治疗方法，这种疾病导致高达 10% 的 HUS 儿童死亡。因此，非常需要更好地了解这种感染的发病机制，以促进开发治疗肠出血性大肠杆菌感染及其并发症的新治疗方法。了解 Stx 摄取和运输进入结肠上皮途径的复杂机制可能有助于确定新的药物靶点并制定旨在防止毒素对人体肠道作用的新策略。在此应用中，我们将使用动物和人类肠上皮细胞模型研究 Stx1 及其 B 亚基 (Stx1B) 的摄取、运输和细胞内作用的机制。在目标 1 中，我们将研究脂筏 (LR) 在 Stx1/Stx1B 跨顶细胞表面易位中的作用。我们建议测试 LR 蛋白的作用，LR 蛋白与毒素易位机制中的毒素受体相关。在目标 2 中，我们将研究新认识的 Stx1/Stx1B 从质膜到核仁的内化途径。在目标 3 中，我们将研究 Stx1/Stx1B 诱导细胞凋亡的机制及其在毒素相关肠道炎症中的作用。这些拟议的研究应该为理解 Stx 介导的肠上皮细胞损伤的分子基础提供新的见解，并有助于设计防止 Stx1 摄取和细胞内作用的策略，从而有助于寻找干扰 EHEC 相关胃肠道病理生理学的新靶点。