Arbovirus midgut escape mechanisms

虫媒病毒中肠逃逸机制

• 批准号: 8237879
• 负责人: ROLLIE J CLEM
• 金额: $ 66.98万
• 依托单位: KANSAS STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-12-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8237879
• 关键词: Address; Aedes; Affect; Alphavirus; Apoptosis; Apoptotic; Arboviruses; Arthropod Vectors; Arthropods; Baculoviruses; Basal lamina; Biochemical; Biochemical Reaction; Biological Assay; Biology; Blood; Bypass; Candidate Disease Gene; Caspase; Cell Death; Cells; Cleaved cell; Culicidae; DNA; Dengue; Dengue Virus; Development; Ensure; Epithelium; Exhibits; Female; Fibroblast Growth Factor; Gene Silencing; Gene Targeting; Genes; Genetic Recombination; Health; Immune; Immunohistochemistry; In Vitro; Induction of Apoptosis; Infection; Ingestion; Insect Vectors; Insecta; Invaded; Lead; Measures; Metalloproteases; Methods; Microscopy; Midgut; Organ; Pathway interactions; Peptide Hydrolases; Phenotype; Physical condensation; Play; Process; Production; Proteins; RNA Interference; Regulator Genes; Research Personnel; Role; Salivary Glands; Secondary to; Signal Transduction; Sindbis Virus; Site; System; Systemic infection; TdT-Mediated dUTP Nick End Labeling Assay; Techniques; Testing; Tissues; Trachea; Transgenic Organisms; Transmission Electron Microscopy; Up-Regulation; Viral; Virus; Virus Diseases; Virus Replication; West Nile virus; Work; Yellow Fever; chikungunya; gain of function; human morbidity; human mortality; in vitro testing; in vivo; inhibitor/antagonist; interest; novel; overexpression; research study; success; transmission process; vector; vector mosquito

DESCRIPTION (provided by applicant): Arboviruses cause a significant world-wide health burden, with well over 100 million people becoming infected each year with viruses such as dengue, West Nile, yellow fever, and chikungunya, among others. Arboviruses are transmitted by arthropod vectors such as mosquitoes that become infected after ingestion of a viremic blood meal from a vertebrate host. Transmission to a new host requires that the arbovirus replicate in the midgut cells of the vector and then spread to secondary tissues eventually reaching the salivary glands. Once the latter are infected, the arthropod is able to transmit the virus to a new host. A long standing question in the field of vector biology is how arboviruses escape from the midgut, bypassing barriers such as basal laminae as well as host immune mechanisms. In some cases, arboviruses are able to infect and replicate in midgut epithelium but are not able to disseminate to other organs. The existence of this so-called midgut escape barrier implies that virus midgut escape is an active process. However, the mechanisms involved in midgut escape by arboviruses are almost completely unknown. This proposal addresses the signaling mechanisms used by the mosquito-borne viruses dengue, chikungunya, and Sindbis viruses to escape the midgut. Previous work by the investigators has defined a novel mechanism used by baculovirus to escape the midgut of their insect host. Baculoviruses use an elegant mechanism that signals a stepwise cascade of protease activation, wherein matrix metalloproteases become activated and in turn activate effector caspases, which directly cleave components of the basal lamina. This leads to remodeling of the basal lamina which lines tracheal cells associated with the midgut and culminates in the establishment of efficient systemic infections. The hypothesis underlying this proposal is that mosquito-borne arboviruses utilize this same pathway for midgut escape, and preliminary results support this hypothesis. Specifically, (1) it will be determined whether the mechanisms used by baculoviruses to remodel the midgut barrier are also utilized by arboviruses, including activation of matrix metalloproteases and caspases; (2) the contribution of candidate genes involved in midgut escape will be evaluated by RNA interference, arbovirus transducing systems, and transgenic Aedes aegypti mosquitoes by silencing or overexpressing target genes; and (3) the contribution of apoptosis and key apoptotic regulatory genes to arbovirus midgut escape will be tested. The results of these studies will contribute important new information to the understanding of arbovirus-vector interactions and potentially lead to new strategies for control of arbovirus transmission in the field. PUBLIC HEALTH RELEVANCE: Arthropod-borne viruses such as dengue, West Nile and yellow fever infect over 100 million people per year and cause significant human morbidity and mortality. After an insect vector is exposed to a virus by taking a blood meal, the virus must disseminate from the midgut to the salivary glands in order to be transmitted to a new host. The specific mechanisms of how these viruses escape from the midgut are not known. The proposed studies will determine the mechanisms used by three mosquito-vectored viruses to escape the midgut and may lead to the development of new strategies to control the transmission of viruses vectored by mosquitoes.

描述（由申请人提供）：虫媒病毒给全世界带来了巨大的健康负担，每年有超过 1 亿人感染登革热、西尼罗河、黄热病和基孔肯雅热等病毒。虫媒病毒通过节肢动物媒介传播，例如蚊子在摄入脊椎动物宿主的病毒血粉后被感染。传播到新宿主需要虫媒病毒在载体的中肠细胞中复制，然后扩散到次级组织，最终到达唾液腺。一旦后者被感染，节肢动物就能够将病毒传播给新的宿主。媒介生物学领域长期存在的一个问题是虫媒病毒如何从中肠逃逸，绕过基底层等屏障以及宿主免疫机制。在某些情况下，虫媒病毒能够在中肠上皮中感染和复制，但不能传播到其他器官。这种所谓的中肠逃逸屏障的存在意味着病毒中肠逃逸是一个主动的过程。然而，虫媒病毒中肠逃逸的机制几乎完全未知。该提案解决了蚊媒病毒登革热、基孔肯雅热和辛德毕斯病毒逃避中肠所使用的信号机制。研究人员之前的工作已经确定了杆状病毒用来逃离昆虫宿主中肠的一种新机制。杆状病毒使用一种优雅的机制，发出蛋白酶激活的逐步级联信号，其中基质金属蛋白酶被激活，进而激活效应半胱天冬酶，后者直接裂解基底层的成分。这导致基底层的重塑，基底层排列着与中肠相关的气管细胞，并最终形成有效的全身感染。该提议的假设是，蚊媒虫媒病毒利用相同的途径进行中肠逃逸，初步结果支持了这一假设。具体来说，（1）确定杆状病毒重塑中肠屏障的机制是否也被虫媒病毒利用，包括基质金属蛋白酶和半胱天冬酶的激活； (2)通过RNA干扰、虫媒病毒转导系统和转基因埃及伊蚊通过沉默或过表达靶基因来评估参与中肠逃逸的候选基因的贡献； (3)将测试细胞凋亡和关键细胞凋亡调节基因对虫媒病毒中肠逃逸的贡献。这些研究的结果将为理解虫媒病毒-载体相互作用提供重要的新信息，并有可能为控制虫媒病毒在现场的传播提供新的策略。 公共卫生相关性：登革热、西尼罗河和黄热病等节肢动物传播的病毒每年感染超过 1 亿人，并导致严重的人类发病和死亡。昆虫媒介通过吸血接触病毒后，病毒必须从中肠传播到唾液腺，才能传播给新宿主。这些病毒如何从中肠逃逸的具体机制尚不清楚。拟议的研究将确定三种蚊媒病毒逃离中肠的机制，并可能导致开发新策略来控制蚊媒病毒的传播。