Location: Foreign Arthropod Borne Animal Disease Research
Project Number: 3022-32000-024-012-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 26, 2022
End Date: Apr 30, 2027
The objective of this study is to determine the roles of exosomes in the transmission of foreign arthropod-borne viruses. Understanding the role of exosomes in the transmission cycle of the virus will identify possible targets for countermeasures to limit the transmission and spread of the virus. Aim 1. Characterize exosomes derived from cultured Culex mosquito cells. Aim 2. Determine effects of virus infection on exosomes derived in vitro from cultured Culex cells. Aim 3. Determine effects of virus infection on exosomes derived in vivo from Culex mosquitoes. Aim 4. Determine if exosomes derived from infected samples can cause systemic infection in uninfected mosquitoes.
Exosomes are a type of extracellular vesicles that play roles in immunity and intercellular communication both within and between species. They have recently become a subject of increasing interest for their potential as delivery vehicles and diagnostic markers in mammalian systems. The physiological roles of exosomes in insects are still largely unexplored, with little information available about their synthesis or composition. However, a few recent publications have suggested that exosomes may have important roles in the interactions between pathogens, hosts, and vectors. In Aedes aegypti, for example, exosomes from cultured Aag2 cells infected with Dengue virus carried infectious viral particles to uninfected mosquito and mammalian cells, demonstrating a role for exosomes in infection of insect cells. Culex mosquites are important vectors of several zoonotic viruses, including Japanese encephalitis virus (JEV) and Rift Valley fever (RVF), but no data are available on the composition of exosomes derived from Culex cells or whether they may play a role in virus transmission. Accordingly, we propose to investigate roles of exosomes in Culex mosquitoes using the following approach: 1. Characterize the RNA and protein cargoes of exosomes derived from cultured Culex mosquito cells. 2. Determine if infection of Culex cells with vaccine strains of JEV or RVF change RNA and protein cargoes of exosomes derived from Culex cells and determine if these exosomes can cause infection in uninfected mammalian and insect cells in vitro. 3. Collect exosomes from Culex mosquitoes infected with JEV and/or RVF and determine if they can cause a systemic infection in uninfected mosquitoes in vivo. The results from these experiments will provide valuable information about how JEV and RVF are transmitted between vector and host as well as how these viruses spread within the tissues of the insect vector. Additionally, the results from these experiments will provide a solid basis for further exploring the roles of exosomes in mosquitoes.