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: 6680759
• 负责人: OLGA KOVBASNJUK
• 金额: $ 24.48万
• 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/6680759
• 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）：美国每年在美国每年有76,000,000例腹泻病。重要的食物传播病原体引起的志贺毒素的大肠杆菌（EHEC）引起的肠道病理，包括美国大约35％的所有血液腹泻的35％脑病。 EHEC是美国儿童目前急性和慢性肾衰竭的主要原因。 EHEC是一种特别令人担忧的食源性病原体，因为EHEC引起的暴发次数继续显着增加，并且这种疾病没有有效的特定疗法，在发展HUS的儿童中最多可致死。因此，非常需要更好地了解这种感染的发病机理，以促进新的治疗方法来治疗EHEC感染及其并发症。了解STX摄取和贩运途径进入结肠上皮的复杂机制可能有助于确定新的药物靶标，并制定旨在防止毒素作用对人类肠道作用的新策略。在此应用中，我们将研究使用动物和人类肠上皮细胞模型的STX1及其B-亚基（STX1B）摄取，运输和细胞内作用的机制。在AIM 1中，我们将研究脂质筏（LR）在顶端细胞表面的STX1/STX1B易位中的作用。我们建议测试LR蛋白的作用，LR蛋白与毒素受体在毒素易位机械中有关。在AIM 2中，我们将研究从质膜到核仁的新认识的STX1/STX1B内部化途径。在AIM 3中，我们将研究STX1/STX1B诱导的细胞凋亡的机制及其在毒素相关肠炎中的作用。这些拟议的研究应提供有关对STX介导的肠上皮细胞损伤分子基础的理解的新见解，并促进设计防止STX1摄取和细胞内作用的策略，从而找到新的靶标，以介入与EHEC相关的胃肠道胃肠道病理学。