scholarly journals Aedes Anphevirus: an Insect-Specific Virus Distributed Worldwide inAedes aegyptiMosquitoes That Has Complex Interplays withWolbachiaand Dengue Virus Infection in Cells

2018 ◽  
Vol 92 (17) ◽  
Author(s):  
Rhys Parry ◽  
Sassan Asgari
Keyword(s):  
Aedes Aegypti ◽  
Dengue Virus ◽  
Cell Line ◽  
Cell Lines ◽  
Virus Replication ◽  
Rna Viruses ◽  
Asia Pacific ◽  
Content Type ◽  
Negative Strand ◽  
Positive Sense

ABSTRACTInsect-specific viruses (ISVs) of the yellow fever mosquitoAedes aegyptihave been demonstrated to modulate transmission of arboviruses such as dengue virus (DENV) and West Nile virus by the mosquito. The diversity and composition of the virome ofA. aegypti, however, remains poorly understood. In this study, we characterized Aedes anphevirus (AeAV), a negative-sense RNA virus from the orderMononegavirales. AeAV identified fromAedescell lines was infectious to bothA. aegyptiandAedes albopictuscells but not to three mammalian cell lines. To understand the incidence and genetic diversity of AeAV, we assembled 17 coding-complete and two partial genomes of AeAV from available transcriptome sequencing (RNA-Seq) data. AeAV appears to transmit vertically and be present in laboratory colonies, wild-caught mosquitoes, and cell lines worldwide. Phylogenetic analysis of AeAV strains indicates that as theA. aegyptimosquito has expanded into the Americas and Asia-Pacific, AeAV has evolved into monophyletic African, American, and Asia-Pacific lineages. The endosymbiotic bacteriumWolbachia pipientisrestricts positive-sense RNA viruses inA. aegypti. Reanalysis of a small RNA library ofA. aegypticells coinfected with AeAV andWolbachiaproduces an abundant RNA interference (RNAi) response consistent with persistent virus replication. We foundWolbachiaenhances replication of AeAV compared to a tetracycline-cleared cell line, and AeAV modestly reduces DENV replicationin vitro. The results from our study improve understanding of the diversity and evolution of the virome ofA. aegyptiand adds to previous evidence that showsWolbachiadoes not restrict a range of negative-strand RNA viruses.IMPORTANCEThe mosquitoAedes aegyptitransmits a number of arthropod-borne viruses (arboviruses), such as dengue virus and Zika virus. Mosquitoes also harbor insect-specific viruses that may affect replication of pathogenic arboviruses in their body. Currently, however, there are only a few insect-specific viruses described fromA. aegyptiin the literature. Here, we characterize a novel negative-strand virus, AeAV. Meta-analysis ofA. aegyptisamples showed that it is present inA. aegyptimosquitoes worldwide and is vertically transmitted.Wolbachia-transinfected mosquitoes are currently being used in biocontrol, as they effectively block transmission of several positive-sense RNA viruses in mosquitoes. Our results demonstrate thatWolbachiaenhances the replication of AeAV and modestly reduces dengue virus replication in a cell line model. This study expands our understanding of the virome inA. aegyptias well as providing insight into the complexity of theWolbachiavirus restriction phenotype.

scholarly journals Cell-Fusing Agent Virus Reduces Arbovirus Dissemination in Aedes aegypti Mosquitoes In Vivo

2019 ◽  
Vol 93 (18) ◽  
Author(s):  
Artem Baidaliuk ◽  
Elliott F. Miot ◽  
Sebastian Lequime ◽  
Isabelle Moltini-Conclois ◽  
Fanny Delaigue ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Dengue Virus ◽  
Cell Line ◽  
Content Type ◽  
Cells In Culture ◽  
Mosquito Cells ◽  
Wide Range ◽  
Natural Hosts

ABSTRACT Aedes aegypti mosquitoes are the main vectors of arthropod-borne viruses (arboviruses) of public health significance, such as the flaviviruses dengue virus (DENV) and Zika virus (ZIKV). Mosquitoes are also the natural hosts of a wide range of viruses that are insect specific, raising the question of their influence on arbovirus transmission in nature. Cell-fusing agent virus (CFAV) was the first described insect-specific flavivirus, initially discovered in an A. aegypti cell line and subsequently detected in natural A. aegypti populations. It was recently shown that DENV and the CFAV strain isolated from the A. aegypti cell line have mutually beneficial interactions in mosquito cells in culture. However, whether natural strains of CFAV and DENV interact in live mosquitoes is unknown. Using a wild-type CFAV isolate recently derived from Thai A. aegypti mosquitoes, we found that CFAV negatively interferes with both DENV type 1 and ZIKV in vitro and in vivo. For both arboviruses, prior infection by CFAV reduced the dissemination titer in mosquito head tissues. Our results indicate that the interactions observed between arboviruses and the CFAV strain derived from the cell line might not be a relevant model of the viral interference that we observed in vivo. Overall, our study supports the hypothesis that insect-specific flaviviruses may contribute to reduce the transmission of human-pathogenic flaviviruses. IMPORTANCE The mosquito Aedes aegypti carries several arthropod-borne viruses (arboviruses) that are pathogenic to humans, including dengue and Zika viruses. Interestingly, A. aegypti is also naturally infected with insect-only viruses, such as cell-fusing agent virus. Although interactions between cell-fusing agent virus and dengue virus have been documented in mosquito cells in culture, whether wild strains of cell-fusing agent virus interfere with arbovirus transmission by live mosquitoes was unknown. We used an experimental approach to demonstrate that cell-fusing agent virus infection reduces the propagation of dengue and Zika viruses in A. aegypti mosquitoes. These results support the idea that insect-only viruses in nature can modulate the ability of mosquitoes to carry arboviruses of medical significance and that they could possibly be manipulated to reduce arbovirus transmission.

scholarly journals Wolbachia wStri Blocks Zika Virus Growth at Two Independent Stages of Viral Replication

mBio ◽  
2018 ◽  
Vol 9 (3) ◽  
Author(s):  
M. J. Schultz ◽  
A. L. Tan ◽  
C. N. Gray ◽  
S. Isern ◽  
S. F. Michael ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Viral Replication ◽  
Yellow Fever ◽  
Virus Replication ◽  
Zika Virus ◽  
Chikungunya Virus ◽  
Yellow Fever Virus ◽  
Rna Viruses ◽  
Content Type ◽  
Infected Cells

ABSTRACTMosquito-transmitted viruses are spread globally and present a great risk to human health. Among the many approaches investigated to limit the diseases caused by these viruses are attempts to make mosquitos resistant to virus infection. Coinfection of mosquitos with the bacteriumWolbachia pipientisfrom supergroup A is a recent strategy employed to reduce the capacity for major vectors in theAedesmosquito genus to transmit viruses, including dengue virus (DENV), Chikungunya virus (CHIKV), and Zika virus (ZIKV). Recently, a supergroup BWolbachia wStri, isolated fromLaodelphax striatellus, was shown to inhibit multiple lineages of ZIKV inAedes albopictuscells. Here, we show thatwStri blocks the growth of positive-sense RNA viruses DENV, CHIKV, ZIKV, and yellow fever virus by greater than 99.9%.wStri presence did not affect the growth of the negative-sense RNA viruses LaCrosse virus or vesicular stomatitis virus. Investigation of the stages of the ZIKV life cycle inhibited bywStri identified two distinct blocks in viral replication. We found a reduction of ZIKV entry intowStri-infected cells. This was partially rescued by the addition of a cholesterol-lipid supplement. Independent of entry, transfected viral genome was unable to replicate inWolbachia-infected cells. RNA transfection and metabolic labeling studies suggested that this replication defect is at the level of RNA translation, where we saw a 66% reduction in mosquito protein synthesis inwStri-infected cells. This study’s findings increase the potential for application ofwStri to block additional arboviruses and also identify specific blocks in viral infection caused byWolbachiacoinfection.IMPORTANCEDengue, Zika, and yellow fever viruses are mosquito-transmitted diseases that have spread throughout the world, causing millions of infections and thousands of deaths each year. Existing programs that seek to contain these diseases through elimination of the mosquito population have so far failed, making it crucial to explore new ways of limiting the spread of these viruses. Here, we show that introduction of an insect symbiont,Wolbachia wStri, into mosquito cells is highly effective at reducing yellow fever virus, dengue virus, Zika virus, and Chikungunya virus production. Reduction of virus replication was attributable to decreases in entry and a strong block of virus gene expression at the translational level. These findings expand the potential use ofWolbachia wStri to block viruses and identify two separate steps for limiting virus replication in mosquitos that could be targeted via microbes or other means as an antiviral strategy.

scholarly journals Aedes anphevirus (AeAV): an insect-specific virus distributed worldwide inAedes aegyptimosquitoes that has complex interplays withWolbachiaand dengue virus infection in cells

2018 ◽  
Author(s):  
Rhys Parry ◽  
Sassan Asgari
Keyword(s):  
Dengue Virus ◽  
Cell Lines ◽  
Rna Viruses ◽  
Rna Virus ◽  
Asia Pacific ◽  
Mammalian Cell Lines ◽  
Persistent Virus ◽  
Specific Virus ◽  
Laboratory Colonies

AbstractInsect specific viruses (ISVs) of the yellow fever mosquitoAedes aegyptihave been demonstrated to modulate transmission of arboviruses such as dengue virus (DENV) and West Nile virus by the mosquito. The diversity and composition of the virome ofAe. aegypti, however, remains poorly understood. In this study, we characterised Aedes anphevirus (AeAV), a negative-sense RNA virus from the orderMononegavirales. AeAV identified fromAedescell lines were infectious to bothAe. aegyptiandAedes albopictuscells, but not to three mammalian cell lines. To understand the incidence and genetic diversity of AeAV, we assembled 17 coding-complete and two partial genomes of AeAV from available RNA-Seq data. AeAV appears to transmit vertically and be present in laboratory colonies, wild-caught mosquitoes and cell lines worldwide. Phylogenetic analysis of AeAV strains indicates that as theAe. aegyptimosquito has expanded into the Americas and Asia-Pacific, AeAV has evolved into monophyletic African, American and Asia-Pacific lineages. The endosymbiotic bacteriumWolbachia pipientisrestricts positive-sense RNA viruses inAe. aegypti. Re-analysis of a small RNA library ofAe. aegypticells co-infected with AeAV andWolbachiaproduces an abundant RNAi response consistent with persistent virus replication. We foundWolbachiaenhances replication of AeAV when compared to a tetracycline cleared cell line, and AeAV modestly reduces DENV replicationin vitro. The results from our study improve understanding of the diversity and evolution of the virome ofAe. aegyptiand adds to previous evidence that showsWolbachiadoes not restrict a range of negative strand RNA viruses.

scholarly journals Using Wolbachia to eliminate dengue – will the virus fight back?

2021 ◽  
Author(s):  
Kathryn M. Edenborough ◽  
Heather A. Flores ◽  
Cameron P. Simmons ◽  
Johanna E. Fraser
Keyword(s):  
Aedes Aegypti ◽  
Dengue Virus ◽  
Rna Viruses ◽  
Field Trials ◽  
Endosymbiotic Bacterium ◽  
Resistant Virus ◽  
Genetic Constraints ◽  
Positive Sense ◽  
Selection For

Recent field trials have demonstrated that dengue incidence can be substantially reduced by introgressing strains of the endosymbiotic bacterium, Wolbachia into Aedes aegypti mosquito populations. This strategy relies on Wolbachia reducing the susceptibility of Ae. aegypti to disseminated infection by positive-sense RNA viruses like dengue. However, RNA viruses are well known to adapt to antiviral pressures. Here we review the viral infection stages where selection for Wolbachia-resistant virus variants could occur. We also consider the genetic constraints imposed on viruses that alternate between vertebrate and invertebrate hosts, and the likely selection pressures that dengue virus might adapt to in order to be effectively transmitted by Ae. aegypti that carry Wolbachia. Whilst there are hurdles to dengue viruses developing resistance to Wolbachia, we suggest that long-term surveillance for resistant viruses should be an integral component of Wolbachia-introgression biocontrol programs.

scholarly journals The Lethal(2)-Essential-for-Life [L(2)EFL] Gene Family Modulates Dengue Virus Infection in Aedes aegypti

2020 ◽  
Vol 21 (20) ◽  
pp. 7520
Author(s):  
Lucky R. Runtuwene ◽  
Shuichi Kawashima ◽  
Victor D. Pijoh ◽  
Josef S. B. Tuda ◽  
Kyoko Hayashida ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Dengue Virus ◽  
Cell Line ◽  
Dengue Infection ◽  
Fruit Fly ◽  
Initiation Factor ◽  
Poly I:C ◽  
Gene Products ◽  
Vector Mosquito

Efforts to determine the mosquito genes that affect dengue virus replication have identified a number of candidates that positively or negatively modify amplification in the invertebrate host. We used deep sequencing to compare the differential transcript abundances in Aedes aegypti 14 days post dengue infection to those of uninfected A. aegypti. The gene lethal(2)-essential-for-life [l(2)efl], which encodes a member of the heat shock 20 protein (HSP20) family, was upregulated following dengue virus type 2 (DENV-2) infection in vivo. The transcripts of this gene did not exhibit differential accumulation in mosquitoes exposed to insecticides or pollutants. The induction and overexpression of l(2)efl gene products using poly(I:C) resulted in decreased DENV-2 replication in the cell line. In contrast, the RNAi-mediated suppression of l(2)efl gene products resulted in enhanced DENV-2 replication, but this enhancement occurred only if multiple l(2)efl genes were suppressed. l(2)efl homologs induce the phosphorylation of eukaryotic initiation factor 2α (eIF2α) in the fruit fly Drosophila melanogaster, and we confirmed this finding in the cell line. However, the mechanism by which l(2)efl phosphorylates eIF2α remains unclear. We conclude that l(2)efl encodes a potential anti-dengue protein in the vector mosquito.

Transcriptional response of Wolbachia-transinfected Aedes aegypti mosquito cells to dengue virus at early stages of infection

2022 ◽  
Vol 103 (1) ◽  
Author(s):  
Michael Leitner ◽  
Kayvan Etebari ◽  
Sassan Asgari
Keyword(s):  
Aedes Aegypti ◽  
Dengue Virus ◽  
Viral Infections ◽  
Transcriptional Response ◽  
Denv Infection ◽  
Content Type ◽  
Public Health Burden ◽  
Immune Genes ◽  
Link Type ◽  
Early Stages

Mosquito-borne flaviviruses are responsible for viral infections and represent a considerable public health burden. Aedes aegypti is the principal vector of dengue virus (DENV), therefore understanding the intrinsic virus–host interactions is vital, particularly in the presence of the endosymbiont Wolbachia, which blocks virus replication in mosquitoes. Here, we examined the transcriptional response of Wolbachia -transinfected Ae. aegypti Aag2 cells to DENV infection. We identified differentially expressed immune genes that play a key role in the activation of anti-viral defence such as the Toll and immune deficiency pathways. Further, genes encoding cytosine and N6-adenosine methyltransferases and SUMOylation, involved in post-transcriptional modifications, an antioxidant enzyme, and heat-shock response were up-regulated at the early stages of DENV infection and are reported here for the first time. Additionally, several long non-coding RNAs were among the differentially regulated genes. Our results provide insight into Wolbachia -transinfected Ae. aegypti’s initial virus recognition and transcriptional response to DENV infection.

scholarly journals Hadaka Virus 1: a Capsidless Eleven-Segmented Positive-Sense Single-Stranded RNA Virus from a Phytopathogenic Fungus, Fusarium oxysporum

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Yukiyo Sato ◽  
Wajeeha Shamsi ◽  
Atif Jamal ◽  
Muhammad Faraz Bhatti ◽  
Hideki Kondo ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Rna Viruses ◽  
Soluble Form ◽  
Phytopathogenic Fungus ◽  
Genomic Rna ◽  
Genomic Rnas ◽  
Content Type ◽  
Positive Sense ◽  
Dsrna Viruses ◽  
Novel Virus

ABSTRACT The search for viruses infecting fungi, or mycoviruses, has extended our knowledge about the diversity of RNA viruses, as exemplified by the discovery of polymycoviruses, a phylogenetic group of multisegmented RNA viruses with unusual forms. The genomic RNAs of known polymycoviruses, which show a phylogenetic affinity for animal positive-sense single-stranded RNA [(+)RNA] viruses such as caliciviruses, are comprised of four conserved segments with an additional zero to four segments. The double-stranded form of polymycovirus genomic RNA is assumed to be associated with a virally encoded protein (proline-alanine-serine-rich protein [PASrp]) in either of two manners: a capsidless colloidal form or a filamentous encapsidated form. Detailed molecular characterizations of polymycoviruses, however, have been conducted for only a few strains. Here, a novel polymyco-related virus named Hadaka virus 1 (HadV1), from the phytopathogenic fungus Fusarium oxysporum, was characterized. The genomic RNA of HadV1 consisted of an 11-segmented positive-sense RNA with highly conserved terminal nucleotide sequences. HadV1 shared the three conserved segments with known polymycoviruses but lacked the PASrp-encoding segment. Unlike the known polymycoviruses and encapsidated viruses, HadV1 was not pelleted by conventional ultracentrifugation, possibly due to the lack of PASrp. This result implied that HadV1 exists only as a soluble form with naked RNA. Nevertheless, the 11 genomic segments of HadV1 have been stably maintained through host subculturing and conidiation. Taken together, the results of this study revealed a virus with a potential novel virus lifestyle, carrying many genomic segments without typical capsids or PASrp-associated forms. IMPORTANCE Fungi collectively host various RNA viruses. Examples include encapsidated double-stranded RNA (dsRNA) viruses with diverse numbers of genomic segments (from 1 to 12) and capsidless viruses with nonsegmented (+)RNA genomes. Recently, viruses with unusual intermediate features of an infectious entity between encapsidated dsRNA viruses and capsidless (+)RNA viruses were found. They are called polymycoviruses, which typically have four to eight dsRNA genomic segments associated with one of the virus-encoded proteins and are phylogenetically distantly related to animal (+)RNA caliciviruses. Here, we identified a novel virus phylogenetically related to polymycoviruses, from the phytopathogenic fungus Fusarium oxysporum. The virus, termed Hadaka virus 1 (HadV1), has 11 (+)RNA genomic segments, the largest number in known (+)RNA viruses. Nevertheless, HadV1 lacked a typical structural protein of polymycoviruses and was not pelleted by standard ultracentrifugation, implying an unusual capsidless nature of HadV1. This study reveals a potential novel lifestyle of multisegmented RNA viruses.

scholarly journals Transcriptome Analysis of Aedes aegypti Aag2 Cells in Response to Dengue Virus-2 Infection

2020 ◽  
Author(s):  
Man-jin Li ◽  
Ce-jie Lan ◽  
He-ting Gao ◽  
Dan Xing ◽  
Zhen-yu Gu ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Dengue Virus ◽  
Cell Line ◽  
Differentially Expressed Genes ◽  
Transcriptome Analysis ◽  
Bioinformatics Analysis ◽  
Differentially Expressed ◽  
Control Group ◽  
Sequencing Data ◽  
Qrt Pcr

Abstract Background: Dengue virus (DENV) is a flavivirus transmitted by mosquitoes that is prevalent in tropical and subtropical countries and has four serotypes (DENV1-4). Aedes aegypti, as the main transmission vector of DENV, exhibits strong infectivity and transmission. With the aim of obtaining a better understanding of the Ae. aegypti-DENV interaction, the transcriptome changes in DENV-2-infected Aag2 cells were studied to describe the immune responses of mosquitoes using the Ae. aegypti Aag2 cell line as a model.Methods: RNAseq technology was used to sequence the transcripts of the Ae. aegypti Aag2 cell line before and after infection with DENV-2. A bioinformatics analysis was then performed to assess the biological functions of the differentially expressed genes, and the sequencing data were verified by quantitative reverse transcription-polymerase chain reaction (qRT-PCR).Results: The transcriptome analysis generated 8866 unigenes that were found in both groups, 225 unigenes that were only found in the infection group, and 683 unigenes that only existed in the control group. A total of 1199 differentially expressed genes, including 1014 upregulated and 185 downregulated genes, were identified. The bioinformatics analysis showed that the differentially expressed genes were mainly involved in the longevity regulating pathway, circadian rhythm, DNA replication, and peroxisome, purine, pyrimidine, and drug metabolism. The qRT-PCR verification results showed the same trend, which confirmed that the expression of the differentially expressed genes had changed and that the transcriptome sequencing data were reliable.Conclusions: This study investigated the changes in the transcriptome levels in the DENV-2-infected Ae. aegypti Aag2 cell line, which provides a faster and effective method for discovering genes related to Ae. aegypti pathogen susceptibility. The findings provide basic data and directions for further research on the complex mechanism underlying host-pathogen interactions.

scholarly journals Under-the-Radar Dengue Virus Infections in Natural Populations of Aedes aegypti Mosquitoes

mSphere ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Sean M. Boyles ◽  
Carla N. Mavian ◽  
Esteban Finol ◽  
Maria Ukhanova ◽  
Caroline J. Stephenson ◽  
...  
Keyword(s):  
United States ◽  
Aedes Aegypti ◽  
Dengue Virus ◽  
The United States ◽  
Human Case ◽  
Mosquito Vector ◽  
Public Health Response ◽  
Content Type ◽  
Virus Serotype ◽  
Dengue Outbreaks

ABSTRACT The incidence of locally acquired dengue infections increased during the last decade in the United States, compelling a sustained research effort concerning the dengue mosquito vector, Aedes aegypti, and its microbiome, which has been shown to influence virus transmission success. We examined the “metavirome” of four populations of Aedes aegypti mosquitoes collected in 2016 to 2017 in Manatee County, FL. Unexpectedly, we discovered that dengue virus serotype 4 (DENV4) was circulating in these mosquito populations, representing the first documented case of such a phenomenon in the absence of a local DENV4 human case in this county over a 2-year period. We confirmed that all of the mosquito populations carried the same DENV4 strain, assembled its full genome, validated infection orthogonally by reverse transcriptase PCR, traced the virus origin, estimated the time period of its introduction to the Caribbean region, and explored the viral genetic signatures and mosquito-specific virome associations that potentially mediated DENV4 persistence in mosquitoes. We discuss the significance of prolonged maintenance of the DENV4 infections in A. aegypti that occurred in the absence of a DENV4 human index case in Manatee County with respect to the inability of current surveillance paradigms to detect mosquito vector infections prior to a potential local outbreak. IMPORTANCE Since 1999, dengue outbreaks in the continental United States involving local transmission have occurred only episodically and only in Florida and Texas. In Florida, these episodes appear to be coincident with increased introductions of dengue virus into the region through human travel and migration from countries where the disease is endemic. To date, the U.S. public health response to dengue outbreaks has been largely reactive, and implementation of comprehensive arbovirus surveillance in advance of predictable transmission seasons, which would enable proactive preventative efforts, remains unsupported. The significance of our finding is that it is the first documented report of DENV4 transmission to and maintenance within a local mosquito vector population in the continental United States in the absence of a human case during two consecutive years. Our data suggest that molecular surveillance of mosquito populations in high-risk, high-tourism areas of the United States may enable proactive, targeted vector control before potential arbovirus outbreaks.

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