Project description:The impact of global climate change on the transmission dynamics of infectious diseases is the subject of extensive debate. The transmission of mosquito-borne viral diseases is particularly complex, with climatic variables directly affecting many parameters associated with the prevalence of disease vectors. While evidence shows that warmer temperatures often decrease the extrinsic incubation period of an arthropod-borne virus (arbovirus), exposure to cooler temperatures often predisposes disease vector mosquitoes to higher infection rates. RNA interference pathways are essential to antiviral immunity in the mosquito; however, few experiments have explored the effects of temperature on the RNAi machinery.
Project description:Cellular models have provided significant advances on molecular bases of bipartite interactions between either an arbovirus or a bacterial symbiont with a given arthropod vector. However, although an interference phenomenon was evidenced in tripartite interaction arbovirus-symbiont-mosquito vector very little is known regarding the mechanisms involved. Using large-scale proteome profiling, we characterized proteins differentially expressed in Aedes albopictus cells infected by the symbiotic bacterium Wolbachia and the Chikungunya virus (CHIKV). These proteins were mostly related to cellular processes involved in glycolysis process, protein metabolism, translation and amino acid metabolism. The presence of Wolbachia impacted significantly the protein profiles, including sequestration of proteins such as structural polyprotein and capsid viral proteins that may affect replication and assembly of CHIKV in cellulo. This study provides insights into the molecular pathways involved in the tripartite interaction mosquito-Wolbachia-virus and may help in defining targets for the better implementation of Wolbachia-based strategy for disease transmission control.
Project description:The impact of global climate change on the transmission dynamics of infectious diseases is the subject of extensive debate. The transmission of mosquito-borne viral diseases is particularly complex, with climatic variables directly affecting many parameters associated with the prevalence of disease vectors. While evidence shows that warmer temperatures often decrease the extrinsic incubation period of an arthropod-borne virus (arbovirus), exposure to cooler temperatures often predisposes disease vector mosquitoes to higher infection rates. RNA interference pathways are essential to antiviral immunity in the mosquito; however, few experiments have explored the effects of temperature on the RNAi machinery. Total small RNAs (miRNAs, siRNAs, piRNAs, etc.) were isolated and sequenced from the heads of sensor strain Aedes aegypti mosquitoes, or from the whole bodies of CHIKV-infected Aedes albopictus mosquitoes 8 hours post infection. Mosquitoes were grown at 18C or 28C in replicates of 1 (Ae. aegypti) or 3 (Ae. albopictus).
Project description:The emergence of mosquito-borne diseases because of climate change emphasizes the need to study arbovirus-vector protein-protein interactions (PPI) to better understand viral replication and transmission. One such human pathogenic arbovirus is Zika virus (ZIKV; Flaviviridae), transmitted by Aedes aegypti mosquitoes. With the lack of molecular tools to study mosquito cells, we developed an Ae. aegypti AF5 cell line stably expressing ZIKV capsid to investigate PPI through label-free quantification proteomics. We identified 157 interactors with 8 potentially pro-viral during ZIKV infection and showed that the transitional endoplasmic reticulum 94 (TER94) protein of the ubiquitin-proteasome pathway (UPP) was important during ZIKV infection in mosquito cells. Silencing TER94 in AF5 cells prevented ZIKV capsid degradation and significantly reduced the establishment of replication at the early stages of infection. Human TER94 ortholog, valosin containing protein (VCP), identified through ortholog mapping, was found to have a similar function during ZIKV infection in A549 cells. ZIKV had reduced ability to replicate when ubiquitination and VCP function were blocked by chemical inhibitors. Furthermore, ubiquitin protein ligase E3 component n-recognin 5 (UBR5) was identified as a TER94/VCP co-factor for capsid interaction. Our study demonstrates a conserved function for TER94/VCP-UPP during early ZIKV infection in mosquito and human cells.
Project description:Aedes mosquitoes transmit pathogenic arthropod-borne (arbo) viruses, putting nearly half the world’s population at risk. Blocking virus replication in mosquitoes rather than in humans serves as a promising approach to prevent arbovirus transmission, which requires in-depth knowledge of mosquito immunity. By integrating multi-omics data, we identified that heat shock factor 1 (Hsf1) regulates eight small heat shock protein (sHsp) genes within one topological associated domain. This Hsf1-sHsp cascade acts as an early response against chikungunya virus (CHIKV) infection and shows pan-antiviral activity in three vector mosquitoes, Aedes aegypti, Aedes albopictus, and Anopheles gambiae. We then assessed the baseline expression of sHsp genes in different tissues of female Ae. aegypti using RNA-seq, and we observed a highly dynamic expression pattern of sHsp genes that varied dramatically across different tissues. Interestingly, sHsp genes were expressed at low levels in two main barrier tissues, the midgut and salivary glands, compared to other tissues such as the crop. Importantly, activation of Hsf1 led to a reduced CHIKV infection rate in adult Ae. aegypti mosquitoes, demonstrating Hsf1 as a promising target for the development of novel intervention strategies to limit arbovirus transmission by mosquitoes.
Project description:Most alphaviruses are transmitted by mosquito vectors and infect a wide range of vertebrate hosts, with a few exceptions. Eilat virus (EILV) in this genus is characterized by a host range restricted to mosquitoes. Its chimeric viruses have been developed as safe and effective vaccine candidates and diagnostic tools. Here, we investigated the interactions between these insect-specific viruses (ISVs) and mosquito cells, unveiling their potential roles in determining vector competence and arbovirus transmission. By RNA sequencing, we found that these ISVs profoundly modified host cell gene expression profiles. Two EILV-based chimeras, consisting of EILV’s nonstructural genes and the structural genes of Chikungunya virus (CHIKV) or Venezuelan equine encephalitis virus (VEEV), namely EILV/CHIKV (E/C) and EILV/VEEV (E/V), induced more intensive transcriptome regulation than parental EILV and activated different antiviral mechanisms in host cells. We demonstrated that E/C robustly promoted antimicrobial peptide production and E/V strongly upregulated the RNA interference pathway components. This also highlighted the intrinsic divergences between CHIKV and VEEV, representatives of the Old World and New World alphaviruses. In contrast, EILV triggered a limited antiviral response. We further showed that initial chimera infections efficiently inhibited subsequent pathogenic alphavirus replication, especially in the case of E/V infection, which almost prevented VEEV and Sindbis virus (SINV) superinfections. Altogether our study provided valuable information on developing ISVs as biological control agents.
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:Aedes aegypti (L.) is the primary vector of many emerging arboviruses. Insecticide resistance among mosquito populations is a consequence of the application of insecticides for mosquito control. We used RNA-sequencing to compare transcriptomes between permethrin resistant and susceptible strains of Florida Ae. aegypti in response to Zika virus infection. A total of 2,459 transcripts were expressed at significantly different levels between resistant and susceptible Ae. aegypti. Gene ontology analysis placed these genes into 7 categories of biological processes. The 863 transcripts were expressed at significantly different levels between two strains (up/down regulated) more than 2-fold. Quantitative real-time PCR analysis validated Zika-infected response, and suggested a highly overexpressed P450, with AAEL014617 and AAEL006798 as potential candidates for the molecular mechanism of permethrin resistance in Ae. aegypti. Our findings indicated that most detoxification enzymes and immune system enzymes altered their gene expression between the two strains of Ae. aegypti in response to Zika virus infection. Understanding the interactions of arboviruses with resistant mosquito vectors at the molecular level allows for the possible development of new approaches in mitigating arbovirus transmission. This information sheds light on Zika-induced changes in the insecticide resistance of Ae. aegypti with implications for mosquito control strategies.
Project description:MalariaM-bM-^@M-^Ys cycle of infection requires parasite transmission between a mosquito vector and a vertebrate host. Plasmodium regulates transmission by translationally repressing specific mRNAs until their products are needed. We demonstrate that the Plasmodium yoelii Pumilio-FBF family member Puf2 allows the sporozoite to retain its infectivity in the mosquito salivary glands while awaiting transmission. Puf2 mediates this critical feature solely through its RNA-Binding Domain (RBD) likely by protecting and silencing specific mRNAs. Puf2 storage granules are distinct from stress granules and P-bodies and dissolve rapidly after infection of hepatocytes, likely releasing the protected and silenced transcripts for M-bM-^@M-^Xjust-in-timeM-bM-^@M-^Y translation by early exoerythrocytic forms (EEFs). Further corroborating this model, pypuf2- sporozoites have no apparent defect in host infection early after invading the salivary glands, but become progressively noninfectious and subsequently prematurely transform into EEFs during prolonged salivary gland residence. In contrast, the premature overexpression of Puf2 in oocysts causes striking deregulation of sporozoite maturation, resulting in fewer oocyst sporozoites that are non-infectious and unable to colonize the salivary glands. Maintenance of Puf2 expression in liver stage parasites produces no phenotype, suggesting that a window of permissive expression exists. Finally, by conducting the first comparative RNAseq analysis of Plasmodium sporozoites, we have uncovered that Puf2 may play a role in both the protection of specific transcripts as well as RNA turnover via the CCR4/Not complex. These findings uncover requirements for maintaining a window of opportunity for the malaria parasite to accommodate the unpredictable moment of transmission from mosquito to vertebrate host. Wild-type (Py17XNL) and pypuf2 -salivary gland sporozoites