Project description:The ability of many viruses to manipulate the host antiviral immune response often results in complex host-pathogen interactions. In order to study the interaction of dengue virus (DENV) with the Aedes aegypti immune response, we have characterized the DENV infection-responsive transcriptome of the immune-competent A. aegypti cell line Aag2. As in mosquitoes, DENV infection transcriptionally activated the cell line Toll pathway and a variety of cellular physiological systems. Most notably, however, DENV infection down-regulated the expression levels of numerous immune signaling molecules and antimicrobial peptides (AMPs). Functional assays showed that transcriptional induction of AMPs from the Toll and IMD pathways in response to bacterial challenge is impaired in DENV-infected cells. In addition, Escherichia coli, a gram-negative bacteria species, grew better when co-cultured with DENV-infected cells than with uninfected cells, suggesting a decreased production of AMPs from the IMD pathway in virus-infected cells. Pre-stimulation of the cell line with gram-positive bacteria prior to DENV infection had no effect on DENV titers, while pre-stimulation with gram-negative bacteria resulted in an increase in DENV titers. These results indicate that DENV is capable of actively suppressing immune responses in the cells it infects, a phenomenon that may have important consequences for virus transmission and insect physiology. Infected (dengue virus or heat-inactivated dengue virus) vs. naive cells. 3 replicates each.
Project description:Two different strains of Aedes aegypti mosquito, Moyo-in-dry and Moyo-S, are profiled for their response through time to infection with Dengue 2 virus. Expression is measured using a two-colour custom spotted cDNA array. A mixed strain uninfected sample is hybridized as the reference.
Project description:Investigation of whole genome gene expression level changes in Moyo-S and Moyo-R strains of Aedes aegypti after oral infection of serotype 1, serotype 2, serotype 3 and serotype 4 of dengue virus The Moyo-S is highly suscpetible to dengue infection whereas Moyo-R is refractory to the dengue infection. They have been investigated in our previous studies incluidng Behura et al. (2011). PLoS neglected tropical diseases 5 (11), e1385; and Chauhan et al. (2012). PloS one 7 (10), e47350.
Project description:We used RNA-sequencing to identify differentially expressed genes in the midgut of Aedes aegypti that contribute to the field derivied dengue susceptible (Cali-S) and dengue refractory (Cali-R) phenotypes
Project description:Arthropod-borne viruses (arboviruses) such as dengue virus (DENV) and Zika virus (ZIKV) pose a significant threat to global health. Novel approaches to control arbovirus spread are focused on harnessing the antiviral immune system of their main vector, the Aedes aegypti mosquito. In arthropods, genes of the Vago family are often presented as analogs of mammalian cytokines with potential antiviral functions, but the role of Vago genes upon virus infection in Ae. aegypti is largely unknown. We performed a phylogenetic analysis of the Vago gene family in Diptera that prompted us to focus on a Vago-like gene that we named VLG-1. Using CRISPR/Cas9-mediated gene editing, we generated a VLG-1 mutant line of Ae. aegypti that revealed a proviral effect of this gene upon DENV and ZIKV infection. In the absence of VLG-1, virus dissemination throughout the mosquito’s body was impaired, albeit not altering virus transmission rates. A tissue-specific transcriptome analysis revealed that the loss of VLG-1 impacted numerous biological processes potentially linked to viral replication, such as the oxidative stress response. Our results challenge the conventional understanding of Vago-like genes as antiviral factors and underscores the need for further research to elucidate the molecular mechanisms underlying mosquito-arbovirus interactions.
Project description:The ability of many viruses to manipulate the host antiviral immune response often results in complex host-pathogen interactions. In order to study the interaction of dengue virus (DENV) with the Aedes aegypti immune response, we have characterized the DENV infection-responsive transcriptome of the immune-competent A. aegypti cell line Aag2. As in mosquitoes, DENV infection transcriptionally activated the cell line Toll pathway and a variety of cellular physiological systems. Most notably, however, DENV infection down-regulated the expression levels of numerous immune signaling molecules and antimicrobial peptides (AMPs). Functional assays showed that transcriptional induction of AMPs from the Toll and IMD pathways in response to bacterial challenge is impaired in DENV-infected cells. In addition, Escherichia coli, a gram-negative bacteria species, grew better when co-cultured with DENV-infected cells than with uninfected cells, suggesting a decreased production of AMPs from the IMD pathway in virus-infected cells. Pre-stimulation of the cell line with gram-positive bacteria prior to DENV infection had no effect on DENV titers, while pre-stimulation with gram-negative bacteria resulted in an increase in DENV titers. These results indicate that DENV is capable of actively suppressing immune responses in the cells it infects, a phenomenon that may have important consequences for virus transmission and insect physiology.
Project description:Wolbachia is a vertically transmitted intracellular bacteria that infect most than 60% of insect species. The strains wMelPop and wMel were introduced in the dengue virus vector Aedes aegypti, naturally not infected by Wolbachia. Recently, it was shown that those two strains inhibit dengue virus replication into their new host, A. aegypti (Moreira et al. 2009 and Walker et al. in preparation). The aim of this project is to look at the transcriptional response of Aedes aegypti to infection with wMel and wMelPop and try to find some genes or pathway potentially involved in the viral interference.Four laboratory lines of A. aegypti were used throughout this study. The PGYP1 and Mel2 lines were generated by transinfection with wMelPop and wMel strains respectively. PGYP1.tet and Mel2tet lines were treated with the antibiotic tetracycline and cured from Wolbachia infection (McMeniman et al., 2009 and Walker et al in preparation). The Mosquitoes were reared under standard laboratory conditions (26 ± 2 °C, 12:12 light/dark cycle, 75% relative humidity). Mosquito larvae were fed 0.1mg/larvae of TetraMin Tropical Tablets once a day. Adults were transferred to cages (measuring 30 x 30 x 30 cm) at emergence at 400 individuals per cage. Adults were supplied with a basic diet of 10% sucrose solution (Turley et al., 2009).
Project description:Zika virus (ZIKV), a pathogen of global health concern, is transmitted to humans by Aedes mosquitoes. However, the molecular interactions between the vector and the virus remain largely unexplored. We demonstrated that ZIKV and dengue virus (DENV) have similar tropism and infection kinetics in two mosquito strains with different degrees of susceptibility to infection. Comparison of Aedes aegypti’s molecular responses to ZIKV and DENV infection indicated that around 40% of the mosquito’s infection-responsive transcriptome is virus-specific. Regulated genes also included key factors of the mosquito’s anti-viral immunity, pointing to the possible involvement of the Toll innate immune pathway. Comparison of ZIKV and DENV infection-responsive transcriptome data to those for yellow fever virus and West Nile virus identified 26 genes likely to play key roles in virus infection of Aedes mosquitoes. Through reverse genetic analyses, we showed that the Toll and the Jak/Stat innate immune pathways mediate increased resistance to ZIKV infection, and the virus use vATPase and inosine-5’-monophosphate dehydrogenase as mosquito’s host factors.