Shiga toxin 1:uptake mechanisms and intracellular action

描述（由申请人提供）：食源性腹泻病在美国每年造成76，000，000例病例。由产滋贺毒素大肠杆菌（EHEC）（重要的食源性病原体）引起的肠道病理学包括美国所有血性腹泻的约35%、水样腹泻的未知%、以及感染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，因为由肠出血性大肠杆菌引起的疫情数量继续显着增加，并且对于这种疾病没有有效的特异性治疗方法，这种疾病在高达10%的发展为HUS的儿童中是致命的。因此，有必要更好地了解这种感染的发病机制，以促进新的治疗方法的发展，以治疗EHEC感染及其并发症。了解Stx吸收和运输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点，并制定新的策略，以防止毒素对人体肠道的作用。在这个应用程序中，我们将研究的机制，Stx 1及其B亚基（Stx 1B）的摄取，运输和细胞内的行动，使用动物和人类肠上皮细胞模型。在目的1中，我们将研究脂筏（LR）在Stx 1/Stx 1B跨顶端细胞表面易位的作用。我们建议测试LR蛋白的作用，这是与毒素转运机制中的毒素受体。在目标2中，我们将研究一个新认识的Stx 1/Stx 1B从质膜到核仁的内化途径。目的3：研究Stx 1/Stx 1B诱导细胞凋亡的机制及其在毒素相关性肠道炎症中的作用。这些拟议的研究应提供新的见解的理解的分子基础的Stx介导的肠上皮细胞损伤，并促进设计的策略，以防止Stx 1的摄取和细胞内的行动，从而有助于找到新的目标，以干扰肠出血性大肠杆菌相关的胃肠道病理生理。

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.