Antiviral Immunity in Mosquitoes

描述（由申请人提供）：许多蚊媒病毒与人类疾病有关。蚊子通过先天免疫反应来保护自己免受病毒感染。因此，蚊子传播的病毒性疾病，如西尼罗热、登革热和基孔肯雅热，只有在病原体能够克服这些防御时才会传播给人类。尽管如此，人们对蚊子的先天免疫知之甚少。我们之前已经证明，在蚊子传播的感染病毒存在的情况下，由小干扰rna （sirna）指导的抗病毒反应对蚊子载体的生存至关重要。然而，最近我们证明了另一类病毒衍生的小rna，与乒乓球依赖的piwi相互作用rna （piRNAs）有许多相似之处，也在蚊子载体的体细胞中产生。我们假设载体蚊子体细胞中存在的非规范piRNA途径与siRNA途径同时作用，形成协调的冗余抗病毒防御。为了支持这一点，我们对多个蚊子细胞系进行了sirna免疫缺陷的表征，然后用这些来证明一类类似的乒乓球依赖性病毒pirna能够建立抗病毒防御，控制病毒感染。在本提案的第一个目标中，我们将定义病毒piRNA生产的生物途径。在该提案的第二个目标中，我们将确定piRNA途径在蚊子体细胞中的抗病毒作用。在本项目结束后，我们将更好地了解蚊子抗病毒免疫和非规范piRNA通路在限制病毒感染中的作用。这一信息将有助于填补我们在蚊媒病毒性疾病流行病学知识方面的空白，并有助于评估基于操纵病毒及其昆虫载体之间的进化军备竞赛的广谱控制战略的可能性。

DESCRIPTION (provided by applicant): Many mosquito-borne viruses are associated with human diseases. Mosquitoes defend themselves against viral infection with an innate immune response. Thus, mosquito-borne viral diseases like West Nile fever, dengue fever, and chikungunya fever are transmitted to humans only when the pathogen is able to overcome these defenses. Despite this, relatively little is known about mosquito innate immunity. We have previously shown that an antiviral response directed by small interfering RNAs (siRNAs) is essential to the survival of mosquito vectors in the presence of an infecting mosquito-borne virus. However, more recently we demonstrated that another class of virus-derived small RNAs, exhibiting many similarities with ping-pong-dependent piwi- interacting RNAs (piRNAs), is also produced in the soma of mosquito vectors. We hypothesize that a non- canonical piRNA pathway present in the soma of vector mosquitoes is acting concurrently with the siRNA pathway to form a coordinated, redundant antiviral defense. In support of this, we characterized multiple mosquito cell lines defective in siRNA-based immunity, and then used these to show that a similar class of ping-pong-dependent viral piRNAs was capable of mounting an antiviral defense that controlled viral infection. In the first aim of this proposal, we will define the biognic pathway of viral piRNA production. In the second aim of the proposal, we will determine the antiviral role of the piRNA pathway in the mosquito soma. At the conclusion of this project, we will have a better understanding of mosquito antiviral immunity and the role of a non-canonical piRNA pathway in restricting virus infection. This information will help address gaps in our knowledge of the epidemiology of mosquito-borne viral diseases and also help to assess possibilities for broad spectrum control strategies that are based on manipulating an evolutionary arms race between viruses and their insect vectors.