P. papatasi midgut molecules: gene function and assessing TBV candidates

描述（由申请人提供）：利什曼病是一种由沙蝇媒介传播的多谱疾病，在许多国家具有重要的社会经济影响。沙蝇与利什曼原虫之间存在着密切的关系，因此，在自然界中，只有某些种类的沙蝇能够传播某些种类的利什曼原虫。这种物种特异性是由几个分子因素驱动的，这些因素使寄生虫能够在沙蝇的中肠内感染、存活和繁殖，并在吸食血液时传播给合适的宿主。一些沙蝇物种被认为是允许的，因为它们能够窝藏几种利什曼原虫的实验性感染（例如卢茨米亚原虫）。longipalpis);其他沙蝇种类被认为是限制性的，因为它们只能感染它们在自然界中携带的利什曼原虫（例如白蛉）。papatasi)。导致这种载体能力的确切相互作用，无论是对于允许的还是限制的载体，仍然需要完全阐明。我们之前定义了大利什曼原虫脂磷酸聚糖和木瓜假单胞菌半凝集素样分子之间的一种特异性相互作用，这种相互作用对载体能力至关重要，并证明了针对该中肠分子的抗体可以防止大利什曼原虫在沙蝇中肠内的建立。在此，我们提出了一套使用这种限制性载体/寄生虫系统的研究，以确定参与沙蝇中肠内利什曼原虫发展的其他沙蝇分子。我们的研究将特别侧重于使用RNA干扰来评估蛋白质的作用，如PpChym2，一种血液诱导的凝乳胰蛋白酶，可能参与利什曼原虫的早期杀伤；PpChit1，一种中肠特异性几丁质酶，被认为在利什曼原虫从营养基质中逃逸中起作用。此外，最近发现的中肠转录物，如编码嗜中性粒细胞和凝血酶特异性抑制剂的转录物也将被评估。一旦确定，有效干扰L. major的papatasi分子也将在其他沙蝇载体组合中进行广谱活性测试，包括P. argenttipes和L. donovani。这项研究将促进有关沙蝇-利什曼原虫相互作用的知识，并将为选择传播阻断候选物作为消除和/或减少利什曼原虫病的策略提供见解。项目说明：白蛉是利什曼病的主要媒介，利什曼病是一种多谱疾病，在发展中国家造成大量发病率和死亡率。由于大多数患者负担不起有效的治疗方法，而且没有疫苗可用，因此基于病媒的战略，特别是传播阻断疫苗正在成为控制许多病媒传播疾病的首选战略。我们的研究旨在评估沉默一些被认为与利什曼原虫在沙蝇体内发育有关的沙蝇蛋白的效果；阐明这些蛋白如何与利什曼原虫相互作用，无疑将有助于开发对抗寄生虫传播的新策略。

DESCRIPTION (provided by applicant): Leishmaniasis, a multi-spectrum disease transmitted by sand fly vectors, has an important social-economic impact in many countries. A strong relationship exists between sand flies and Leishmania such that, in nature, only certain species of sand flies are able to transmit certain species of Leishmania. Such species-specificity is driven by several molecular factors that allow the parasite to infect, survive and multiply within the midgut of the sand fly and be transmitted to a suitable host during a blood meal. Some sand fly species are considered permissive in that they are able to harbor experimental infections of several Leishmania species (e.g. Lutzomyia. longipalpis); other sand fly species are considered restrictive as they can only be infected with the Leishmania species that they carry in nature (e.g. Phlebotomus. papatasi). The precise interactions that lead to this vector competence, whether for permissive or restrictive vectors, remain to be completely elucidated. We previously defined one specific interaction between L. major lipophosphoglycan and a P. papatasi galectin-like molecule that is essential for vector competence and demonstrated that antibodies targeted to this midgut molecule prevent establishment of Leishmania major within the sand fly midgut. Here we propose a set of studies using this restrictive vector/parasite system, to identify additional sand fly molecules that participate in the development of Leishmania within the sand fly midgut. Our studies will specifically focus on the use of RNA interference to assess the roles of proteins such as PpChym2, a blood-induced chymotrypsin that may be involved in early killing of Leishmania; and PpChit1, a midgut-specific chitinase that is thought to play a role in Leishmania escape from the peritrophic matrix. Additionally, recently identified midgut transcripts such as those coding for peritrophins and thrombin-specific inhibitors will also be evaluated. Once identified, P. papatasi molecules that effectively interfere with the development of L. major also will be tested for their broad spectrum activity in other sand fly vector combinations, including P. argentipes and L. donovani. This research will advance the knowledge regarding sand fly-Leishmania interaction and will provide insights for the selection of transmission blocking candidates as a strategy to eliminate and/or reduce leishmaniasis. Project Narrative: Phlebotomine sand flies are the main vectors of leishmaniasis, a multi-spectrum disease that causes substantial morbidity and mortality in the developing world. As effective therapies are un-affordable to most patients and no vaccines are available, vector-based strategies, specifically transmission-blocking vaccines are becoming a choice strategy to control many vector transmitted diseases. Our studies aim at assessing the effect of silencing a selected number of sand fly proteins thought to be involved in Leishmania development within the sand fly; elucidating how these proteins interact with Leishmania parasites undoubtedly will lead to the development of novel strategies to fight parasite transmission.