RNAi screen to identify host factors involved in Chlamydia pathogenesis

描述（由申请人提供）：衣原体是革兰氏阴性细菌病原体，可感染广泛的宿主并引起各种疾病，包括发展中国家的可预防性失明，性传播疾病和肺炎。衣原体侵入细胞并在一种被称为包涵体的膜结合的隔室内复制，这种隔室可能充当抵抗免疫监视的保护罩，也充当与宿主细胞交换因子的“过滤器”。尽管衣原体作为一种人类病原体具有重要意义，但对感染过程中涉及的细菌和宿主因素知之甚少。这种知识的缺乏主要是由于衣原体不是一种遗传易感的生物，以及在哺乳动物宿主中进行遗传方法的困难。

DESCRIPTION (provided by applicant): Chlamydia are gram-negative bacterial pathogens that infect a wide range of hosts and cause various diseases, including preventable blindness in developing countries, sexually transmitted disease and pneumonia. Chlamydia invade cells and replicate within a membrane-bound compartment, named the inclusion, that potentially serves as a protector shield against immune surveillance and also acts as a "filter" to exchange factors with the host cell. Despite the primary importance of Chlamydia as a human pathogen, little is known about the bacterial and host factors involved in the infection process. This paucity of knowledge is mainly due to the fact that Chlamydia is not a genetically tractable organism and to the difficulty of conducting genetic approaches in the mammalian host. To further get insights into the mechanisms involved in Chlamydia pathogenesis, we have developed a genetic approach in the model organism Drosophila melanogaster. We have shown that Drosophila SL2 cells constitute a viable model to study Chlamydia infection. We demonstrated that, similar to the situation in mammalian cells, infectious forms (EB) of C. caviae, the guinea pig model of genital and ocular infection of C. trachomatis, enter Drosophila SL2 cells, differentiate into the replicative form (RB), replicate within a membrane-bound compartment and differentiate back from RBs to EBs. Using this model system, we have performed a genome wide RNAi screen and identify 450 host that when depleted increased or decreased C. caviae intracellular growth. We now propose: (1) to confirm the candidates identified in the primary screen, (2) to identify the host factors specifically involved in Chlamydia infection, (3) to validate the selected Chlamydia-specific candidates in a mammalian system. Altogether, our genetic approach should lead to the identification of uncovered host factors involved in Chlamydia pathogenesis. Our long-term goal is to characterize the function of the identified candidates in order to better understand the complex interaction between Chlamydia and its host and potentially identify novel targets for therapeutic treatment.