Developing comparative and functional genomic approaches to study Schistosoma

描述(申请人提供)：血吸虫病是一种被忽视的热带疾病，影响着发展中国家的2亿多人。目前只有一种药物(吡喹酮)可用于治疗这种疾病，这突显了开发研究这些寄生虫的新技术的重要性。尽管存在研究血吸虫的重要工具(例如基因组序列和RNA干扰)，但血吸虫生命周期的复杂性继续阻碍开发新疗法的进展。具体地说，目前还不可能进行大规模、无偏见的功能性基因组筛查来识别新的药物靶点。我们的长期目标是在血吸虫中识别新的治疗靶点，我们目前的目标是使用实验上容易驯化的自由生活的平虫作为模型来识别和破译“扁虫特有的”基因的功能。尽管它们的生活方式不同(自由生活与寄生)，但这些动物在解剖学和基因组水平上都有许多基本的相似之处。鉴于这些相似之处，我们的假设是，许多对生理、繁殖和生存至关重要的过程在这些扁虫之间是非常保守的。为了解决这一假设，我们提出了以下两个具体目标：(1)鉴定扁虫特异的生存或繁殖所需的基因；(2)开发新的技术来干扰成虫体内的基因功能。在第一个目标中，我们将使用高通量原位杂交来比较108个扁虫特异性基因在曼氏血吸虫和地中海血吸虫中的组织特异性表达。我们还将使用RNA干扰来确定这些基因在稻瘟病菌中的功能丧失表型。这些研究将为特定目标2中提出的体内功能研究提供候选基因列表。由于目前还不可能在体内对成虫进行基因操作，我们的第二个目标将确定体内吗啉是否能在感染小鼠体内诱导成虫组织中的基因敲除。这些方法将被用来检查在特定目标#1中确定的基因是否在体内血吸虫生物学中发挥重要作用。这些研究具有创新性，因为它们(I)引入地中海血吸虫作为模型来加速血吸虫的功能基因组研究，以及(Ii)开发基于吗啉的技术来在哺乳动物宿主中对成虫进行遗传操作。这些研究具有重要意义，因为它们描述了一种潜在的有效的抗血吸虫靶标发现工作流程：在地中海血吸虫中进行大规模筛查，并使用vivo-Morolinos在体内验证候选药物。总而言之，我们的研究将试图填补寄生扁虫功能基因组研究的重要空白，并有可能确定血吸虫的新治疗靶点。 公共卫生相关性：这些研究与公共卫生相关，因为它们旨在开发新的方法来了解人类病原体曼氏血吸虫的基因功能。这项拟议研究的完成可能有助于发现抗击这种重要的人类寄生虫引起的疾病的新药。

DESCRIPTION (provided by applicant): Schistosomiasis is a neglected tropical disease that affects more than 200 million people in the developing world. Currently only a single drug (praziquantel) is available to treat this disease, highlighting the importance of developing new techniques to study these parasites. Although important tools exist to study Schistosoma (e.g. genome sequences and RNA interference), the complexity of the schistosome life cycle continues to hinder progress towards developing novel therapeutics. Specifically, large-scale, unbiased functional genomic screens to identify new drug targets are currently not possible. With the long-term goal of identifying novel therapeutic targets in Schistosoma, our current objective is to use the experimentally tractable free-living flatworm S. mediterranea as a model to identify and decipher the function of "flatworm-specific" genes. Despite their divergent lifestyles (free-living vs. parasitic), these animals share many fundamental similarities, both at the anatomic and genomic levels. Given these similarities, our hypothesis is that many processes essential for physiology, reproduction, and viability are deeply conserved between these flatworms. To address this hypothesis we propose the following two specific aims: (1) Identify flatworm-specific genes required for viability or reproduction and (2) Develop novel techniques to disrupt adult schistosome gene function in vivo. In the first aim, we will use high-throughput in situ hybridization to compare the tissue-specific expression of 108 flatworm-specific genes in Schistosoma mansoni and S. mediterranea. We will also determine the loss-of-function phenotype for these genes in S. mediterranea using RNA interference. These studies will provide a candidate gene list for in vivo functional studies proposed in specific aim #2. Since it is presently not possible to genetically manipulate adult schistosomes in vivo, our second aim will determine if vivo-morpholinos can induce gene knockdown in adult schistosome tissues inside infected mice. These approaches will be used to examine if genes identified in specific aim #1 have important roles in schistosome biology in vivo. These studies are innovative because they (i) introduce S. mediterranea as a model to accelerate functional genomic studies of Schistosoma and (ii) develop morpholino-based techniques to genetically manipulate adult schistosomes in the mammalian host. These studies are significant since they describe a potentially potent workflow for anti-schistosomal target discovery: large-scale screening in S. mediterranea and in vivo candidate validation using vivo-morpholinos. Collectively, our studies will attempt to fill important gaps in functional genomic studies of parasitic flatworms and have the potential to identify new therapeutic targets in Schistosoma. PUBLIC HEALTH RELEVANCE: These studies are pertinent to public health since they aim to develop novel ways to understand the function of genes in the human pathogen Schistosoma mansoni. Completion of the proposed research could aid in the discovery of new drugs to combat disease caused by this important human parasite.