Aedes aegypti (Aag2)-derived clonal mosquito cell lines reveal the effects of pre-existing persistent infection with the insect-specific bunyavirus Phasi Charoen-like virus on arbovirus replication

Abstract

BackgroundAedes aegypti is a vector mosquito of major public health importance, transmitting arthropod-borne viruses (arboviruses) such as chikungunya, dengue, yellow fever and Zika viruses. Wild mosquito populations are persistently infected at high prevalence with insect-specific viruses that do not replicate in vertebrate hosts. In experimental settings, acute infections with insect-specific viruses have been shown to modulate arbovirus infection and transmission in Ae. aegypti and other vector mosquitoes. However, the impact of persistent insect-specific virus infections, which arboviruses encounter more commonly in nature, has not been investigated extensively. Cell lines are useful models for studying virus-host interactions, however the available Ae. aegypti cell lines are poorly defined and heterogenous cultures.Methodology/Principle findingsWe generated single cell-derived clonal cell lines from the commonly used Ae. aegypti cell line Aag2. Two of the fourteen Aag2-derived clonal cell lines generated harboured markedly and consistently reduced levels of the insect-specific bunyavirus Phasi Charoen-like virus (PCLV) known to persistently infect Aag2 cells. In contrast to studies with acute insect-specific virus infections in cell culture and in vivo, we found that pre-existing persistent PCLV infection had no major impact on the replication of the flaviviruses dengue virus and Zika virus, the alphavirus Sindbis virus, or the rhabdovirus vesicular stomatitis virus. We also performed a detailed characterisation of the morphology, transfection efficiency and immune status of our Aag2-derived clonal cell lines, and have made a clone that we term Aag2-AF5 available to the research community as a well-defined cell culture model for arbovirus-vector interaction studies.Conclusions/SignificanceOur findings highlight the need for further in vivo studies that more closely recapitulate natural arbovirus transmission settings in which arboviruses encounter mosquitoes harbouring persistent rather than acute insect-specific virus infections. Furthermore, we provide the well-characterised Aag2-derived clonal cell line as a valuable resource to the arbovirus research community.

Endogenous piRNA-guided slicing triggers responder and trailer piRNA production from viral RNA inAedes aegyptimosquitoes

“…Interestingly, we also observe sharp 3' ends and +1U biases for piRNAs generated from Phasi Charoen-like virus ( Figure S1), a negative sense RNA virus from the Phenuiviridae family that persistently infects Aag2 cells (38). These findings indicate that Zuc-like piRNA biogenesis targets diverse RNA viruses.…”

Stability of the Virome in Lab- and Field-Collected Aedes albopictus Mosquitoes across Different Developmental Stages and Possible Core Viruses in the Publicly Available Virome Data of Aedes Mosquitoes

“…However, the effects of these viruses on their host are very poorly understood. A recent study revealed that preexisting infection of Aag2 cells with PCLPV did not affect the infection and growth of the mosquito-borne viruses in genus Flavivirus, Alphavirus, and Rhabdovirus in cell culture (42). GMV is a recently described two-segmented, currently unclassified virus.…”

The conservation of a core virome inAedesmosquitoes across different developmental stages and continents

“…However, the effects of these viruses on their host is very poorly understood. A recent study revealed that Aag2 cells with pre-existing infection with PCLPV do not affect the infection and growth of the mosquito-borne viruses in genus Flavivirus , Alphavirus and Rhabdovirus in cell culture [69]. GMV is a recently described two-segmented, currently unclassified virus.…”