Drosophila melanogaster as a model host for Vibrio cholerae

描述(申请人提供)：霍乱弧菌，一种在水环境中发现的革兰氏阴性嗜盐细菌，是霍乱流行和致命腹泻疾病的病原体。我们以前已经证明，黑腹果蝇摄入霍乱弧菌致病菌株会导致致死性感染。这种感染依赖于细菌对霍乱毒素的表达，以及苍蝇体内野生型腺酰环化酶、GSA和钙激活的K通道的存在。这些发现支持霍乱毒素是人类和果蝇感染的主要毒力因素的结论，并且在这两种生物中的作用机制相似。基于这些结果，我们推测苍蝇可能是一个有用和实用的模式宿主，用来识别影响霍乱弧菌感染过程的宿主因素。为此，我们启动了正向遗传筛查，以鉴定其易感性高的果蝇突变体。这些实验将为未来以苍蝇为模型的研究奠定基础，以确定霍乱的新治疗方法、霍乱弧菌免疫反应的调节器，以及影响哺乳动物宿主对霍乱弧菌感染的易感性的因素。我们建议完成以下具体目标： 具体目标1：完成基因筛查，以确定影响果蝇对霍乱弧菌感染敏感性的宿主蛋白。 特定目的2：确定肠道细胞凋亡是果蝇对霍乱弧菌感染易感性的一个因素，并确定调控肠道细胞凋亡的信号通路。 具体目标3：确定霍乱弧菌刺激细胞凋亡反应的因子。

DESCRIPTION (provided by applicant): Vibrio cholerae, a gram-negative halophilic bacterium found in aquatic environments is the causative agent of the epidemic and deadly diarrheal disease cholera. We have previously shown that ingestion of pathogenic strains of V. cholerae by Drosophila melanogaster results in lethal infection. This infection is dependent on cholera toxin expression by the bacterium as well as on the presence of wild-type levels of adenylyl cyclase, Gsa, and Ca2+-activated K+ channels in the fly. These findings support the conclusion that cholera toxin is the primary virulence factor in both human and Drosophila infection and acts by a similar mechanism in both of these organisms. Based on these results, we hypothesize that the fly may be a useful and practical model host in which to identify host factors that impact the course of V. cholerae infection. To this end, we have initiated a forward genetic screen to identify Drosophila mutants whose susceptibility ty. These experiments will lay the ground work for future studies using the fly as a model to identify novel therapeutics for cholera, modulators of the immune response to V. cholerae, and factors that influence the susceptibility of the mammalian host to V. cholerae infection. We propose to complete the following specific aims: Specific Aim 1: Completion of a genetic screen to identify host proteins that impact the susceptibility of Drosophila melanogaster to V. cholerae infection. Specific Aim 2: To establish intestinal apoptosis as a factor in the susceptibility of Drosophila to V. cholerae infection and to identify the Drosophila signaling pathways that modulate intestinal apoptosis. Specific Aim 3: To identify Vibrio cholerae factors those are responsible for stimulation of the apoptotic response.