RESUMO
Noncoding RNAs have regulatory capabilities that evolution harnesses to fulfill diverse functions. Lee et al. show that a noncoding RNA from Epstein-Barr virus recruits a host transcription factor to silence virus gene expression and propose that it does this through base-pairing with nascent viral transcripts.
Assuntos
Herpesvirus Humano 4/metabolismo , Fator de Transcrição PAX5/metabolismo , RNA Viral/metabolismo , HumanosRESUMO
Mosquito transmission of dengue viruses to humans starts with infection of skin resident cells at the biting site. There is great interest in identifying transmission-enhancing factors in mosquito saliva in order to counteract them. Here we report the discovery of high levels of the anti-immune subgenomic flaviviral RNA (sfRNA) in dengue virus 2-infected mosquito saliva. We established that sfRNA is present in saliva using three different methods: northern blot, RT-qPCR and RNA sequencing. We next show that salivary sfRNA is protected in detergent-sensitive compartments, likely extracellular vesicles. In support of this hypothesis, we visualized viral RNAs in vesicles in mosquito saliva and noted a marked enrichment of signal from 3'UTR sequences, which is consistent with the presence of sfRNA. Furthermore, we show that incubation with mosquito saliva containing higher sfRNA levels results in higher virus infectivity in a human hepatoma cell line and human primary dermal fibroblasts. Transfection of 3'UTR RNA prior to DENV2 infection inhibited type I and III interferon induction and signaling, and enhanced viral replication. Therefore, we posit that sfRNA present in salivary extracellular vesicles is delivered to cells at the biting site to inhibit innate immunity and enhance dengue virus transmission.
Assuntos
Aedes , Culicidae , Dengue , Flavivirus , Animais , Humanos , Flavivirus/genética , RNA Subgenômico , Saliva/metabolismo , Regiões 3' não Traduzidas , Replicação Viral , RNA Viral/genética , RNA Viral/metabolismoRESUMO
Mosquito blood-feeding behavior is a key determinant of the epidemiology of dengue viruses (DENV), the most-prevalent mosquito-borne viruses. However, despite its importance, how DENV infection influences mosquito blood-feeding and, consequently, transmission remains unclear. Here, we developed a high-resolution, video-based assay to observe the blood-feeding behavior of Aedes aegypti mosquitoes on mice. We then applied multivariate analysis on the high-throughput, unbiased data generated from the assay to ordinate behavioral parameters into complex behaviors. We showed that DENV infection increases mosquito attraction to the host and hinders its biting efficiency, the latter resulting in the infected mosquitoes biting more to reach similar blood repletion as uninfected mosquitoes. To examine how increased biting influences DENV transmission to the host, we established an in vivo transmission model with immuno-competent mice and demonstrated that successive short probes result in multiple transmissions. Finally, to determine how DENV-induced alterations of host-seeking and biting behaviors influence dengue epidemiology, we integrated the behavioral data within a mathematical model. We calculated that the number of infected hosts per infected mosquito, as determined by the reproduction rate, tripled when mosquito behavior was influenced by DENV infection. Taken together, this multidisciplinary study details how DENV infection modulates mosquito blood-feeding behavior to increase vector capacity, proportionally aggravating DENV epidemiology. By elucidating the contribution of mosquito behavioral alterations on DENV transmission to the host, these results will inform epidemiological modeling to tailor improved interventions against dengue.
Assuntos
Aedes/virologia , Vírus da Dengue/fisiologia , Dengue/transmissão , Dengue/virologia , Comportamento Alimentar/fisiologia , Interações Hospedeiro-Patógeno/fisiologia , Animais , Comportamento Animal/fisiologia , Análise MultivariadaRESUMO
Dengue viruses (DENV) are expanding global pathogens that are transmitted through the bite of mosquitoes, mostly Aedes aegypti. As RNA viruses, DENV rely on RNA-binding proteins (RBPs) to complete their life cycle. Alternatively, RBPs can act as restriction factors that prevent DENV multiplication. While the importance of RBPs is well-supported in humans, there is a dearth of information about their influence on DENV transmission by mosquitoes. Such knowledge could be harnessed to design novel, effective interventions against DENV. Here, we successfully adapted RNA-affinity chromatography coupled with mass spectrometry-a technique initially developed in mammalian cells-to identify RBPs in Ae. aegypti cells. We identified fourteen RBPs interacting with DENV serotype 2 3'UTR, which is involved in the viral multiplication and produces subgenomic flaviviral RNA (sfRNA). We validated the RNA affinity results for two RBPs by confirming that AePur binds the 3'UTR, whereas AeStaufen interacts with both 3'UTR and sfRNA. Using in vivo functional evaluation, we determined that RBPs like AeRan, AeExoRNase, and AeRNase have pro-viral functions, whereas AeGTPase, AeAtu, and AePur have anti-viral functions in mosquitoes. Furthermore, we showed that human and mosquito Pur homologs have a shared affinity to DENV2 RNA, although the anti-viral effect is specific to the mosquito protein. Importantly, we revealed that AeStaufen mediates a reduction of gRNA and sfRNA copies in several mosquito tissues, including the salivary glands and that AeStaufen-mediated sfRNA reduction diminishes the concentration of transmission-enhancing sfRNA in saliva, thereby revealing AeStaufen's role in DENV transmission. By characterizing the first RBPs that associate with DENV2 3'UTR in mosquitoes, our study unravels new pro- and anti-viral targets for the design of novel therapeutic interventions as well as provides foundation for studying the role of RBPs in virus-vector interactions.
Assuntos
Aedes , Vírus da Dengue , Dengue , Regiões 3' não Traduzidas/genética , Aedes/genética , Animais , Proteínas de Transporte/genética , Vírus da Dengue/genética , Humanos , Mamíferos , Mosquitos Vetores/genética , RNA Guia de Cinetoplastídeos , Proteínas de Ligação a RNA/genética , SalivaRESUMO
Dengue virus (DENV) subdues cell membranes for its cellular cycle by reconfiguring phospholipids in humans and mosquitoes. Here, we determined how and why DENV reconfigures phospholipids in the mosquito vector. By inhibiting and activating the de novo phospholipid biosynthesis, we demonstrated the antiviral impact of de novo-produced phospholipids. In line with the virus hijacking lipids for its benefit, metabolomics analyses indicated that DENV actively inhibited the de novo phospholipid pathway and instead triggered phospholipid remodeling. We demonstrated the early induction of remodeling during infection by using isotope tracing in mosquito cells. We then confirmed in mosquitoes the antiviral impact of de novo phospholipids by supplementing infectious blood meals with a de novo phospholipid precursor. Eventually, we determined that phospholipid reconfiguration was required for viral genome replication but not for the other steps of the virus cellular cycle. Overall, we now propose that DENV reconfigures phospholipids through the remodeling cycle to modify the endomembrane and facilitate formation of the replication complex. Furthermore, our study identified de novo phospholipid precursor as a blood determinant of DENV human-to-mosquito transmission.
Assuntos
Aedes/virologia , Vírus da Dengue/fisiologia , Dengue/transmissão , Mosquitos Vetores/virologia , Fosfolipídeos/biossíntese , Aedes/enzimologia , Animais , Linhagem Celular , Membrana Celular/metabolismo , Dengue/prevenção & controle , Dengue/virologia , Vírus da Dengue/patogenicidade , Genoma Viral , Humanos , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Metabolismo dos Lipídeos/genética , Redes e Vias Metabólicas/genética , Metabolômica , Mosquitos Vetores/enzimologia , Interferência de RNA , RNA Viral/metabolismo , Replicação ViralRESUMO
Arbovirus infection of Aedes aegypti salivary glands (SGs) determines transmission. However, there is a dearth of knowledge on SG immunity. Here, we characterized SG immune response to dengue, Zika and chikungunya viruses using high-throughput transcriptomics. We also describe a transcriptomic response associated to apoptosis, blood-feeding and lipid metabolism. The three viruses differentially regulate components of Toll, Immune deficiency (IMD) and c-Jun N- terminal Kinase (JNK) pathways. However, silencing of the Toll and IMD pathway components showed variable effects on SG infection by each virus. In contrast, regulation of the JNK pathway produced consistent responses in both SGs and midgut. Infection by the three viruses increased with depletion of the activator Kayak and decreased with depletion of the negative regulator Puckered. Virus-induced JNK pathway regulates the complement factor, Thioester containing protein-20 (TEP20), and the apoptosis activator, Dronc, in SGs. Individual and co-silencing of these genes demonstrate their antiviral effects and that both may function together. Co-silencing either TEP20 or Dronc with Puckered annihilates JNK pathway antiviral effect. Upon infection in SGs, TEP20 induces antimicrobial peptides (AMPs), while Dronc is required for apoptosis independently of TEP20. In conclusion, we revealed the broad antiviral function of JNK pathway in SGs and showed that it is mediated by a TEP20 complement and Dronc-induced apoptosis response. These results expand our understanding of the immune arsenal that blocks arbovirus transmission.
Assuntos
Aedes/imunologia , Apoptose , Febre de Chikungunya/imunologia , Proteínas do Sistema Complemento/imunologia , Dengue/imunologia , Sistema de Sinalização das MAP Quinases , Glândulas Salivares/imunologia , Infecção por Zika virus/imunologia , Aedes/virologia , Animais , Febre de Chikungunya/metabolismo , Febre de Chikungunya/prevenção & controle , Febre de Chikungunya/virologia , Vírus Chikungunya/imunologia , Proteínas do Sistema Complemento/metabolismo , Dengue/metabolismo , Dengue/prevenção & controle , Dengue/virologia , Vírus da Dengue/imunologia , Feminino , Interações Hospedeiro-Patógeno , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Insetos Vetores/imunologia , Insetos Vetores/virologia , Glândulas Salivares/virologia , Transcriptoma , Replicação Viral , Zika virus/imunologia , Infecção por Zika virus/metabolismo , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/virologiaRESUMO
More than half of the world population is at risk of dengue virus (DENV) infection because of the global distribution of its mosquito vectors. DENV is an envelope virus that relies on host lipid membranes for its life-cycle. Here, we characterized how DENV hijacks the mosquito lipidome to identify targets for novel transmission-blocking interventions. To describe metabolic changes throughout the mosquito DENV cycle, we deployed a Liquid chromatography-high resolution mass spectrometry (LC-HRMS) workflow including spectral similarity annotation in cells, midguts and whole mosquitoes at different times post infection. We revealed a major aminophospholipid reconfiguration with an overall early increase, followed by a reduction later in the cycle. We phylogenetically characterized acylglycerolphosphate acyltransferase (AGPAT) enzyme isoforms to identify those that catalyze a rate-limiting step in phospholipid biogenesis, the acylation of lysophosphatidate to phosphatidate. We showed that DENV infection decreased AGPAT1, but did not alter AGPAT2 expression in cells, midguts and mosquitoes. Depletion of either AGPAT1 or AGPAT2 increased aminophospholipids and partially recapitulated DENV-induced reconfiguration before infection in vitro. However, only AGPAT1 depletion promoted infection by maintaining high aminophospholipid concentrations. In mosquitoes, AGPAT1 depletion also partially recapitulated DENV-induced aminophospholipid increase before infection and enhanced infection by maintaining high aminophospholipid concentrations. These results indicate that DENV inhibition of AGPAT1 expression promotes infection by increasing aminophospholipids, as observed in the mosquito's early DENV cycle. Furthermore, in AGPAT1-depleted mosquitoes, we showed that enhanced infection was associated with increased consumption/redirection of aminophospholipids. Our study suggests that DENV regulates aminophospholipids, especially phosphatidylcholine and phosphatidylethanolamine, by inhibiting AGPAT1 expression to increase aminophospholipid availability for virus multiplication.
Assuntos
1-Acilglicerol-3-Fosfato O-Aciltransferase/metabolismo , Vírus da Dengue/metabolismo , Proteínas de Insetos/metabolismo , Mosquitos Vetores/metabolismo , Mosquitos Vetores/virologia , Aedes , Animais , Interações Hospedeiro-Parasita/fisiologia , Fosfolipídeos/metabolismoRESUMO
The four dengue viruses (DENV1-4) are rapidly reemerging infectious RNA viruses. These positive-strand viral genomes contain structured 3' untranslated regions (UTRs) that interact with various host RNA binding proteins (RBPs). These RBPs are functionally important in viral replication, pathogenesis, and defense against host immune mechanisms. Here, we combined RNA chromatography and quantitative mass spectrometry to identify proteins interacting with DENV1-4 3' UTRs. As expected, RBPs displayed distinct binding specificity. Among them, we focused on quaking (QKI) because of its preference for the DENV4 3' UTR (DENV-4/SG/06K2270DK1/2005). RNA immunoprecipitation experiments demonstrated that QKI interacted with DENV4 genomes in infected cells. Moreover, QKI depletion enhanced infectious particle production of DENV4. On the contrary, QKI did not interact with DENV2 3' UTR, and DENV2 replication was not affected consistently by QKI depletion. Next, we mapped the QKI interaction site and identified a QKI response element (QRE) in DENV4 3' UTR. Interestingly, removal of QRE from DENV4 3' UTR abolished this interaction and increased DENV4 viral particle production. Introduction of the QRE to DENV2 3' UTR led to QKI binding and reduced DENV2 infectious particle production. Finally, reporter assays suggest that QKI reduced translation efficiency of viral RNA. Our work describes a novel function of QKI in restricting viral replication.
Assuntos
Regiões 3' não Traduzidas , Antivirais/farmacologia , Vírus da Dengue/efeitos dos fármacos , Dengue/prevenção & controle , RNA Viral/genética , Proteínas de Ligação a RNA/metabolismo , Replicação Viral/efeitos dos fármacos , Dengue/genética , Dengue/virologia , Genoma Viral , Células HEK293 , Humanos , Proteínas de Ligação a RNA/genéticaRESUMO
Flaviviruses, such as dengue, Japanese encephalitis, tick-borne encephalitis, West Nile, yellow fever, and Zika viruses, are critically important human pathogens that sicken a staggeringly high number of humans every year. Most of these pathogens are transmitted by mosquitos, and not surprisingly, as the earth warms and human populations grow and move, their geographic reach is increasing. Flaviviruses are simple RNA-protein machines that carry out protein synthesis, genome replication, and virion packaging in close association with cellular lipid membranes. In this review, we examine the molecular biology of flaviviruses touching on the structure and function of viral components and how these interact with host factors. The latter are functionally divided into pro-viral and antiviral factors, both of which, not surprisingly, include many RNA binding proteins. In the interface between the virus and the hosts we highlight the role of a noncoding RNA produced by flaviviruses to impair antiviral host immune responses. Throughout the review, we highlight areas of intense investigation, or a need for it, and potential targets and tools to consider in the important battle against pathogenic flaviviruses.
Assuntos
Flavivirus/fisiologia , Flavivirus/classificação , Flavivirus/genética , Flavivirus/metabolismo , Genes Virais , Interações Hospedeiro-Patógeno , Humanos , Proteínas de Ligação a RNA/metabolismo , Replicação ViralRESUMO
Quaking (QKI) is an RNA-binding protein (RBP) involved in multiple aspects of RNA metabolism and many biological processes. Despite a known immune function in regulating monocyte differentiation and inflammatory responses, the degree to which QKI regulates the host interferon (IFN) response remains poorly characterized. Here we show that QKI ablation enhances poly(I:C) and viral infection-induced IFNß transcription. Characterization of IFN-related signalling cascades reveals that QKI knockout results in higher levels of IRF3 phosphorylation. Interestingly, complementation with QKI-5 isoform alone is sufficient to rescue this phenotype and reduce IRF3 phosphorylation. Further analysis shows that MAVS, but not RIG-I or MDA5, is robustly upregulated in the absence of QKI, suggesting that QKI downregulates MAVS and thus represses the host IFN response. As expected, MAVS depletion reduces IFNß activation and knockout of MAVS in the QKI knockout cells completely abolishes IFNß induction. Consistently, ectopic expression of RIG-I activates stronger IFNß induction via MAVS-IRF3 pathway in the absence of QKI. Collectively, these findings demonstrate a novel role for QKI in negatively regulating host IFN response by reducing MAVS levels.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Interações Hospedeiro-Patógeno/fisiologia , Interferon Tipo I/metabolismo , Proteínas de Ligação a RNA/metabolismo , Células A549 , Proteínas Adaptadoras de Transdução de Sinal/genética , Sistemas CRISPR-Cas , Regulação da Expressão Gênica , Humanos , Fator Regulador 3 de Interferon/genética , Fator Regulador 3 de Interferon/metabolismo , Interferon Tipo I/genética , Fosforilação , Poli I-C/genética , Poli I-C/metabolismo , Proteínas de Ligação a RNA/genética , Infecções por Respirovirus/metabolismo , Vírus Sendai/patogenicidadeRESUMO
Globally re-emerging dengue viruses are transmitted from human-to-human by Aedes mosquitoes. While viral determinants of human pathogenicity have been defined, there is a lack of knowledge of how dengue viruses influence mosquito transmission. Identification of viral determinants of transmission can help identify isolates with high epidemiological potential. Additionally, mechanistic understanding of transmission will lead to better understanding of how dengue viruses harness evolution to cycle between the two hosts. Here, we identified viral determinants of transmission and characterized mechanisms that enhance production of infectious saliva by inhibiting immunity specifically in salivary glands. Combining oral infection of Aedes aegypti mosquitoes and reverse genetics, we identified two 3' UTR substitutions in epidemic isolates that increased subgenomic flaviviral RNA (sfRNA) quantity, infectious particles in salivary glands and infection rate of saliva, which represents a measure of transmission. We also demonstrated that various 3'UTR modifications similarly affect sfRNA quantity in both whole mosquitoes and human cells, suggesting a shared determinism of sfRNA quantity. Furthermore, higher relative quantity of sfRNA in salivary glands compared to midgut and carcass pointed to sfRNA function in salivary glands. We showed that the Toll innate immune response was preferentially inhibited in salivary glands by viruses with the 3'UTR substitutions associated to high epidemiological fitness and high sfRNA quantity, pointing to a mechanism for higher saliva infection rate. By determining that sfRNA is an immune suppressor in a tissue relevant to mosquito transmission, we propose that 3'UTR/sfRNA sequence evolution shapes dengue epidemiology not only by influencing human pathogenicity but also by increasing mosquito transmission, thereby revealing a viral determinant of epidemiological fitness that is shared between the two hosts.
Assuntos
Aedes/imunologia , Aedes/virologia , Vírus da Dengue/fisiologia , Dengue/transmissão , Insetos Vetores/imunologia , Insetos Vetores/virologia , Animais , Dengue/virologia , Vírus da Dengue/genética , Humanos , RNA Viral/genética , RNA Viral/metabolismo , Glândulas Salivares/imunologia , Glândulas Salivares/virologia , Replicação ViralRESUMO
The Flavivirus genus contains several arthropod-borne viruses that pose global health threats, including dengue viruses (DENV), yellow fever virus (YFV), and Zika virus (ZIKV). In order to understand how these viruses replicate in human cells, we previously conducted genome-scale RNA interference screens to identify candidate host factors. In these screens, we identified ribosomal proteins RPLP1 and RPLP2 (RPLP1/2) to be among the most crucial putative host factors required for DENV and YFV infection. RPLP1/2 are phosphoproteins that bind the ribosome through interaction with another ribosomal protein, RPLP0, to form a structure termed the ribosomal stalk. RPLP1/2 were validated as essential host factors for DENV, YFV, and ZIKV infection in two human cell lines: A549 lung adenocarcinoma and HuH-7 hepatoma cells, and for productive DENV infection of Aedes aegypti mosquitoes. Depletion of RPLP1/2 caused moderate cell-line-specific effects on global protein synthesis, as determined by metabolic labeling. In A549 cells, global translation was increased, while in HuH-7 cells it was reduced, albeit both of these effects were modest. In contrast, RPLP1/2 knockdown strongly reduced early DENV protein accumulation, suggesting a requirement for RPLP1/2 in viral translation. Furthermore, knockdown of RPLP1/2 reduced levels of DENV structural proteins expressed from an exogenous transgene. We postulate that these ribosomal proteins are required for efficient translation elongation through the viral open reading frame. In summary, this work identifies RPLP1/2 as critical flaviviral host factors required for translation. IMPORTANCE: Flaviviruses cause important diseases in humans. Examples of mosquito-transmitted flaviviruses include dengue, yellow fever and Zika viruses. Viruses require a plethora of cellular factors to infect cells, and the ribosome plays an essential role in all viral infections. The ribosome is a complex macromolecular machine composed of RNA and proteins and it is responsible for protein synthesis. We identified two specific ribosomal proteins that are strictly required for flavivirus infection of human cells and mosquitoes: RPLP1 and RPLP2 (RPLP1/2). These proteins are part of a structure known as the ribosomal stalk and help orchestrate the elongation phase of translation. We show that flaviviruses are particularly dependent on the function of RPLP1/2. Our findings suggest that ribosome composition is an important factor for virus translation and may represent a regulatory layer for translation of specific cellular mRNAs.
Assuntos
Infecções por Flavivirus/metabolismo , Infecções por Flavivirus/virologia , Flavivirus/fisiologia , Interações Hospedeiro-Patógeno , Fosfoproteínas/metabolismo , Proteínas Ribossômicas/metabolismo , Proteínas Virais/metabolismo , Aedes/virologia , Animais , Linhagem Celular , Vírus da Dengue/fisiologia , Infecções por Flavivirus/genética , Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Fosfoproteínas/química , Fosfoproteínas/genética , Ligação Proteica , Multimerização Proteica , Proteínas Ribossômicas/química , Proteínas Ribossômicas/genética , Replicação Viral , Vírus da Febre Amarela/fisiologiaRESUMO
Thioester-containing protein 1 (TEP1) is a key immune factor that determines mosquito resistance to a wide range of pathogens, including malaria parasites. Here we report a new allele-specific function of TEP1 in male fertility. We demonstrate that during spermatogenesis TEP1 binds to and removes damaged cells through the same complement-like cascade that kills malaria parasites in the mosquito midgut. Further, higher fertility rates are mediated by an allele that renders the mosquito susceptible to Plasmodium. By elucidating the molecular and genetic mechanisms underlying TEP1 function in spermatogenesis, our study suggests that pleiotropic antagonism between reproduction and immunity may shape resistance of mosquito populations to malaria parasites.
Assuntos
Anopheles/metabolismo , Proteínas de Insetos/metabolismo , Espermatogênese , Alelos , Animais , Animais Geneticamente Modificados , Anopheles/imunologia , Feminino , Fertilidade , Raios gama , Pleiotropia Genética , Interações Hospedeiro-Parasita , Insetos Vetores/imunologia , Insetos Vetores/metabolismo , Masculino , Plasmodium/imunologia , Espermatozoides/metabolismo , Testículo/metabolismoRESUMO
Anopheline mosquitoes are the only vectors of human malaria worldwide. It is now widely accepted that mosquito immune responses play a crucial role in restricting Plasmodium development within the vector; therefore, further dissection of the molecular mechanisms underlying these processes should inform new vector control strategies urgently needed to roll back the disease. Here, using genome-wide transcriptional profiling, bioinformatics, and functional gene analysis, we identify a new axis of mosquito resistance to monoclonal Plasmodium falciparum infections that includes the AP-1 transcription factor Fos and the transglutaminase 2 (TGase2), a cross-linking enzyme with known roles in wound responses. We demonstrate that Fos regulates induction of TGase2 expression after wounding but does not affect expression of the components of the well characterized complement-like system. Silencing of Fos or of TGase2 aborts the wounding-induced mosquito killing of P. falciparum. These results reveal multiple signaling pathways that are required for efficient Plasmodium killing in Anopheles gambiae.
Assuntos
Anopheles/metabolismo , Anopheles/parasitologia , Proteínas de Ligação ao GTP/metabolismo , Proteínas de Insetos/metabolismo , Plasmodium falciparum/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Fator de Transcrição AP-1/metabolismo , Transglutaminases/metabolismo , Animais , Anopheles/genética , Proteínas de Ligação ao GTP/genética , Estudo de Associação Genômica Ampla , Humanos , Proteínas de Insetos/genética , Proteína 2 Glutamina gama-Glutamiltransferase , Proteínas Proto-Oncogênicas c-fos/genética , Fator de Transcrição AP-1/genética , Transglutaminases/genéticaRESUMO
The global public health burden exerted by viruses partially stems from viruses' ability to subdue host cells into creating an environment that promotes their multiplication (i.e., pro-viral). It has been discovered that viruses alter cell physiology by transferring viral material through extracellular vesicles (EVs), which serve as vehicles for intercellular communication. Here, we aim to provide a conceptual framework of all possible EV-virus associations and their resulting functions in infection output. First, we describe the different viral materials potentially associated with EVs by reporting that EVs can harbor entire virions, viral proteins and viral nucleic acids. We also delineate the different mechanisms underlying the internalization of these viral components into EVs. Second, we describe the potential fate of EV-associated viral material cargo by detailing how EV can circulate and target a naive cell once secreted. Finally, we itemize the different pro-viral strategies resulting from EV associations as the Trojan horse strategy, an alternative mode of viral transmission, an expansion of viral cellular tropism, a pre-emptive alteration of host cell physiology and an immunity decoy. With this conceptual overview, we aim to stimulate research on EV-virus interactions.
Assuntos
Exossomos , Vesículas Extracelulares , Vesículas Extracelulares/metabolismo , Transporte Biológico , Estruturas Virais , Exossomos/metabolismoRESUMO
Dengue (DENV) and chikungunya (CHIKV) viruses are among the most preponderant arboviruses. Although primarily transmitted through the bite of Aedes aegypti mosquitoes, Aedes albopictus and Aedes malayensis are competent vectors and have an impact on arbovirus epidemiology. Here, to fill the gap in our understanding of the molecular interactions between secondary vectors and arboviruses, we used transcriptomics to profile the whole-genome responses of A. albopictus to CHIKV and of A. malayensis to CHIKV and DENV at 1 and 4 days post-infection (dpi) in midguts. In A. albopictus, 1793 and 339 genes were significantly regulated by CHIKV at 1 and 4 dpi, respectively. In A. malayensis, 943 and 222 genes upon CHIKV infection, and 74 and 69 genes upon DENV infection were significantly regulated at 1 and 4 dpi, respectively. We reported 81 genes that were consistently differentially regulated in all the CHIKV-infected conditions, identifying a CHIKV-induced signature. We identified expressed immune genes in both mosquito species, using a de novo assembled midgut transcriptome for A. malayensis, and described the immune architectures. We found the JNK pathway activated in all conditions, generalizing its antiviral function to Aedines. Our comprehensive study provides insight into arbovirus transmission by multiple Aedes vectors.
Assuntos
Aedes , Febre de Chikungunya , Vírus Chikungunya , Dengue , Animais , Transcriptoma , Aedes/genética , Vírus Chikungunya/genética , Febre de Chikungunya/genética , Mosquitos Vetores/genética , Dengue/genéticaRESUMO
Among emerging zoonotic pathogens, mosquito-borne viruses (MBVs) circulate between vertebrate animals and mosquitoes and represent a serious threat to humans via spillover from enzootic cycles to the human community. Active surveillance of MBVs in their vectors is therefore essential to better understand and prevent spillover and emergence, especially at the human-animal interface. In this study, we assessed the presence of MBVs using molecular and phylogenetic methods in mosquitoes collected along an ecological gradient ranging from rural urbanized areas to highland forest areas in northern Thailand. We have detected the presence of insect specific flaviviruses in our samples, and the presence of the emerging zoonotic Tembusu virus (TMUV). Reported for the first time in 1955 in Malaysia, TMUV remained for a long time in the shadow of other flaviviruses such as dengue virus or the Japanese encephalitis virus. In this study, we identified two new TMUV strains belonging to cluster 3, which seems to be endemic in rural areas of Thailand and highlighted the genetic specificities of this Thai cluster. Our results show the active circulation of this emerging flavivirus in Thailand and the need for continuous investigation on this poorly known but threatening virus in Asia.
Assuntos
Culex , Culicidae , Flavivirus , Animais , Humanos , Filogenia , Tailândia/epidemiologia , Mosquitos Vetores , Flavivirus/genéticaRESUMO
Mosquito saliva proteins modulate the human immune and hemostatic systems and control mosquito-borne pathogenic infections. One mechanism through which mosquito proteins may influence host immunity and hemostasis is their interactions with key human receptor proteins that may act as receptors for or coordinate attacks against invading pathogens. Here, using pull-down assays and proteomics-based mass spectrometry, we identified 11 Ae. aegypti salivary gland proteins (SGPs) (e.g., apyrase, Ae. aegypti venom allergen-1 [AaVA-1], neutrophil stimulating protein 1 [NeSt1], and D7 proteins), that interact with one or more of five human receptor proteins (cluster of differentiation 4 [CD4], CD14, CD86, dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin [DC-SIGN], and Toll-like receptor 4 [TLR4]). We focused on CD4- and DC-SIGN-interacting proteins and confirmed that CD4 directly interacts with AaVA-1, D7, and NeST1 recombinant proteins and that AaVA-1 showed a moderate interaction with DC-SIGN using ELISA. Bacteria responsive protein 1 (AgBR1), an Ae. aegypti saliva protein reported to enhance ZIKV infection in humans but that was not identified in our pull-down assay moderately interacts with CD4 in the ELISA assay. Functionally, we showed that AaVA-1 and NeST1 proteins promoted activation of CD4+ T cells. We propose the possible impact of these interactions and effects on mosquito-borne viral infections such as dengue, Zika, and chikungunya viruses. Overall, this study provides key insight into the vector-host (protein-protein) interaction network and suggests roles for these interactions in mosquito-borne viral infections.