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1.
Nature ; 580(7802): 274-277, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32269344

RESUMO

Tandem repeat elements such as the diverse class of satellite repeats occupy large parts of eukaryotic chromosomes, mostly at centromeric, pericentromeric, telomeric and subtelomeric regions1. However, some elements are located in euchromatic regions throughout the genome and have been hypothesized to regulate gene expression in cis by modulating local chromatin structure, or in trans via transcripts derived from the repeats2-4. Here we show that a satellite repeat in the mosquito Aedes aegypti promotes sequence-specific gene silencing via the expression of two PIWI-interacting RNAs (piRNAs). Whereas satellite repeats and piRNA sequences generally evolve extremely quickly5-7, this locus was conserved for approximately 200 million years, suggesting that it has a central function in mosquito biology. piRNA production commenced shortly after egg laying, and inactivation of the more abundant piRNA resulted in failure to degrade maternally deposited transcripts in the zygote and developmental arrest. Our results reveal a mechanism by which satellite repeats regulate global gene expression in trans via piRNA-mediated gene silencing that is essential for embryonic development.


Assuntos
Aedes/embriologia , Aedes/genética , DNA Satélite/genética , RNA Interferente Pequeno/genética , Animais , Sequência de Bases , Feminino , Inativação Gênica
2.
PLoS Pathog ; 18(11): e1010694, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36441781

RESUMO

Aedes aegypti mosquitoes are responsible for the transmission of arthropod-borne (arbo)viruses including dengue and chikungunya virus (CHIKV) but in contrast to human hosts, arbovirus-infected mosquitoes are able to efficiently control virus replication to sub-pathological levels. Yet, our knowledge of the molecular interactions of arboviruses with their mosquito hosts is incomplete. Here, we aimed to identify and characterize novel host genes that control arbovirus replication in Aedes mosquitoes. RNA binding proteins (RBPs) are well-known to regulate immune signaling pathways in all kingdoms of life. We therefore performed a knockdown screen targeting 461 genes encoding predicted RBPs in Aedes aegypti Aag2 cells and identified 15 genes with antiviral activity against Sindbis virus. Amongst these, the three DEAD-box RNA helicases AAEL004419/Dhx15, AAEL008728, and AAEL004859 also acted as antiviral factors in dengue and CHIKV infections. Here, we explored the mechanism of Dhx15 in regulating an antiviral transcriptional response in mosquitoes by silencing Dhx15 in Aag2 cells followed by deep-sequencing of poly-A enriched RNAs. Dhx15 knockdown in uninfected and CHIKV-infected cells resulted in differential expression of 856 and 372 genes, respectively. Interestingly, amongst the consistently downregulated genes, glycolytic process was the most enriched gene ontology (GO) term as the expression of all core enzymes of the glycolytic pathway was reduced, suggesting that Dhx15 regulates glycolytic function. A decrease in lactate production indicated that Dhx15 silencing indeed functionally impaired glycolysis. Modified rates of glycolytic metabolism have been implicated in controlling the replication of several classes of viruses and strikingly, infection of Aag2 cells with CHIKV by itself also resulted in the decrease of several glycolytic genes. Our data suggests that Dhx15 regulates replication of CHIKV, and possibly other arboviruses, by controlling glycolysis in mosquito cells.


Assuntos
Aedes , Humanos , Animais , Aedes/genética , Ontologia Genética , RNA Helicases DEAD-box/genética
3.
RNA ; 27(10): 1155-1172, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34210890

RESUMO

PIWI-interacting (pi)RNAs are small silencing RNAs that are crucial for the defense against transposable elements in germline tissues of animals. In Aedes aegypti mosquitoes, the piRNA pathway also contributes to gene regulation in somatic tissues, illustrating additional roles for piRNAs and PIWI proteins besides transposon repression. Here, we identify a highly abundant endogenous piRNA (propiR1) that associates with both Piwi4 and Piwi5. PropiR1-mediated target silencing requires base-pairing in the seed region with supplemental base-pairing at the piRNA 3' end. Yet, propiR1 represses a limited set of targets, among which is the lncRNA AAEL027353 (lnc027353). Slicing of lnc027353 initiates production of responder and trailer piRNAs from the cleavage fragment. Expression of propiR1 commences early during embryonic development and mediates degradation of maternally provided lnc027353 Both propiR1 and its lncRNA target are conserved in the closely related Aedes albopictus mosquito, underscoring the importance of this regulatory network for mosquito development.


Assuntos
Aedes/genética , Desenvolvimento Embrionário/genética , Regulação da Expressão Gênica no Desenvolvimento , Inativação Gênica , RNA Longo não Codificante/genética , RNA Interferente Pequeno/genética , Aedes/embriologia , Aedes/metabolismo , Animais , Pareamento de Bases , Sequência de Bases , Sequência Conservada , Embrião não Mamífero , Redes Reguladoras de Genes , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , RNA Longo não Codificante/metabolismo
4.
Nucleic Acids Res ; 49(15): 8886-8899, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34331446

RESUMO

In the germline of animals, PIWI interacting (pi)RNAs protect the genome against the detrimental effects of transposon mobilization. In Drosophila, piRNA-mediated cleavage of transposon RNA triggers the production of responder piRNAs via ping-pong amplification. Responder piRNA 3' end formation by the nuclease Zucchini is coupled to the production of downstream trailer piRNAs, expanding the repertoire of transposon piRNA sequences. In Aedes aegypti mosquitoes, piRNAs are generated from viral RNA, yet, it is unknown how viral piRNA 3' ends are formed and whether viral RNA cleavage gives rise to trailer piRNA production. Here we report that in Ae. aegypti, virus- and transposon-derived piRNAs have sharp 3' ends, and are biased for downstream uridine residues, features reminiscent of Zucchini cleavage of precursor piRNAs in Drosophila. We designed a reporter system to study viral piRNA 3' end formation and found that targeting viral RNA by abundant endogenous piRNAs triggers the production of responder and trailer piRNAs. Using this reporter, we identified the Ae. aegypti orthologs of Zucchini and Nibbler, two nucleases involved in piRNA 3' end formation. Our results furthermore suggest that autonomous piRNA production from viral RNA can be triggered and expanded by an initial cleavage event guided by genome-encoded piRNAs.


Assuntos
Elementos de DNA Transponíveis/genética , Densovirinae/genética , Proteínas de Drosophila/genética , Endorribonucleases/genética , RNA Interferente Pequeno/genética , RNA Viral/genética , Aedes/genética , Aedes/virologia , Animais , Proteínas Argonautas/genética , Densovirinae/patogenicidade , Drosophila melanogaster/genética , Drosophila melanogaster/virologia , Células Germinativas/virologia , Clivagem do RNA/genética
5.
Proc Natl Acad Sci U S A ; 116(48): 24296-24302, 2019 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-31712431

RESUMO

Coevolution of viruses and their hosts may lead to viral strategies to avoid, evade, or suppress antiviral immunity. An example is antiviral RNA interference (RNAi) in insects: the host RNAi machinery processes viral double-stranded RNA into small interfering RNAs (siRNAs) to suppress viral replication, whereas insect viruses encode suppressors of RNAi, many of which inhibit viral small interfering RNA (vsiRNA) production. Yet, many studies have analyzed viral RNAi suppressors in heterologous systems, due to the lack of experimental systems to manipulate the viral genome of interest, raising questions about in vivo functions of RNAi suppressors. To address this caveat, we generated an RNAi suppressor-defective mutant of invertebrate iridescent virus 6 (IIV6), a large DNA virus in which we previously identified the 340R protein as a suppressor of RNAi. Loss of 340R did not affect vsiRNA production, indicating that 340R binds siRNA duplexes to prevent RNA-induced silencing complex assembly. Indeed, vsiRNAs were not efficiently loaded into Argonaute 2 during wild-type IIV6 infection. Moreover, IIV6 induced a limited set of mature microRNAs in a 340R-dependent manner, most notably miR-305-3p, which we attribute to stabilization of the miR-305-5p:3p duplex by 340R. The IIV6 340R deletion mutant did not have a replication defect in cells, but was strongly attenuated in adult Drosophila This in vivo replication defect was completely rescued in RNAi mutant flies, indicating that 340R is a bona fide RNAi suppressor, the absence of which uncovers a potent antiviral immune response that suppresses virus accumulation ∼100-fold. Together, our work indicates that viral RNAi suppressors may completely mask antiviral immunity.


Assuntos
Drosophila/genética , Drosophila/virologia , Interações Hospedeiro-Patógeno/imunologia , Iridovirus/fisiologia , Iridovirus/patogenicidade , Animais , Drosophila/imunologia , Regulação da Expressão Gênica , Interações Hospedeiro-Patógeno/genética , MicroRNAs/genética , Microrganismos Geneticamente Modificados , Mutação , Interferência de RNA , Estabilidade de RNA , Proteínas Virais/genética , Proteínas Virais/imunologia , Replicação Viral
6.
Mol Ecol ; 30(7): 1594-1611, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33432714

RESUMO

Horizontal gene transfer from viruses to eukaryotic cells is a pervasive phenomenon. Somatic viral integrations are linked to persistent viral infection whereas integrations into germline cells are maintained in host genomes by vertical transmission and may be co-opted for host functions. In the arboviral vector Aedes aegypti, an endogenous viral element from a nonretroviral RNA virus (nrEVE) was shown to produce PIWI-interacting RNAs (piRNAs) to limit infection with a cognate virus. Thus, nrEVEs may constitute a heritable, sequence-specific mechanism for antiviral immunity, analogous to piRNA-mediated silencing of transposable elements. Here, we combine population genomics and evolutionary approaches to analyse the genomic architecture of nrEVEs in A. aegypti. We conducted a genome-wide screen for adaptive nrEVEs and searched for novel population-specific nrEVEs in the genomes of 80 individual wild-caught mosquitoes from five geographical populations. We show a dynamic landscape of nrEVEs in mosquito genomes and identified five novel nrEVEs derived from two currently circulating viruses, providing evidence of the environmental-dependent modification of a piRNA cluster. Overall, our results show that virus endogenization events are complex with only a few nrEVEs contributing to adaptive evolution in A. aegypti.


Assuntos
Aedes , Aedes/genética , Animais , Genômica , Metagenômica , Mosquitos Vetores/genética , RNA Interferente Pequeno/genética
7.
Nucleic Acids Res ; 47(5): 2546-2559, 2019 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-30566680

RESUMO

PIWI-interacting RNAs (piRNAs) comprise a class of small RNAs best known for suppressing transposable elements in germline tissues. The vector mosquito Aedes aegypti encodes seven PIWI genes, four of which are somatically expressed. This somatic piRNA pathway generates piRNAs from viral RNA during infection with cytoplasmic RNA viruses through ping-pong amplification by the PIWI proteins Ago3 and Piwi5. Yet, additional insights into the molecular mechanisms mediating non-canonical piRNA production are lacking. TUDOR-domain containing (Tudor) proteins facilitate piRNA biogenesis in Drosophila melanogaster and other model organisms. We thus hypothesized that Tudor proteins are required for viral piRNA production and performed a knockdown screen targeting all A. aegypti Tudor genes. Knockdown of the Tudor genes AAEL012437, Vreteno, Yb, SMN and AAEL008101-RB resulted in significantly reduced viral piRNA levels, with AAEL012437-depletion having the strongest effect. This protein, which we named Veneno, associates directly with Ago3 in an sDMA-dependent manner and localizes in cytoplasmic foci reminiscent of piRNA processing granules of Drosophila. Veneno-interactome analyses reveal a network of co-factors including the orthologs of the Drosophila piRNA pathway components Vasa and Yb, which in turn interacts with Piwi5. We propose that Veneno assembles a multi-protein complex for ping-pong dependent piRNA production from viral RNA.


Assuntos
Aedes/genética , Proteínas de Drosophila/genética , RNA Interferente Pequeno/genética , Domínio Tudor/genética , Aedes/patogenicidade , Animais , Proteínas Argonautas/genética , Elementos de DNA Transponíveis/genética , Drosophila melanogaster/genética , Células Germinativas/crescimento & desenvolvimento , Mosquitos Vetores/genética , Complexos Multiproteicos/genética
8.
Nucleic Acids Res ; 45(8): 4881-4892, 2017 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-28115625

RESUMO

The piRNA pathway is of key importance in controlling transposable elements in most animal species. In the vector mosquito Aedes aegypti, the presence of eight PIWI proteins and the accumulation of viral piRNAs upon arbovirus infection suggest additional functions of the piRNA pathway beyond genome defense. To better understand the regulatory potential of this pathway, we analyzed in detail host-derived piRNAs in A. aegypti Aag2 cells. We show that a large repertoire of protein-coding genes and non-retroviral integrated RNA virus elements are processed into genic piRNAs by different combinations of PIWI proteins. Among these, we identify a class of genes that produces piRNAs from coding sequences in an Ago3- and Piwi5-dependent fashion. We demonstrate that the replication-dependent histone gene family is a genic source of ping-pong dependent piRNAs and that histone-derived piRNAs are dynamically expressed throughout the cell cycle, suggesting a role for the piRNA pathway in the regulation of histone gene expression. Moreover, our results establish the Aag2 cell line as an accessible experimental model to study gene-derived piRNAs.


Assuntos
Aedes/genética , Proteínas Argonautas/genética , Histonas/genética , RNA Interferente Pequeno/genética , Animais , Elementos de DNA Transponíveis/genética , Proteínas de Drosophila/genética , Regulação da Expressão Gênica , RNA Interferente Pequeno/biossíntese
9.
PLoS Pathog ; 12(12): e1006017, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28033427

RESUMO

Vector mosquitoes are responsible for transmission of the majority of arthropod-borne (arbo-) viruses. Virus replication in these vectors needs to be sufficiently high to permit efficient virus transfer to vertebrate hosts. The mosquito immune response therefore is a key determinant for arbovirus transmission. Mosquito antiviral immunity is primarily mediated by the small interfering RNA pathway. Besides this well-established antiviral machinery, the PIWI-interacting RNA (piRNA) pathway processes viral RNA into piRNAs. In recent years, significant progress has been made in characterizing the biogenesis and function of these viral piRNAs. In this review, we discuss these developments, identify knowledge gaps, and suggest directions for future research.


Assuntos
Arbovírus/genética , Culicidae/virologia , Insetos Vetores/virologia , RNA Interferente Pequeno/genética , RNA Viral/genética , Animais
10.
BMC Genomics ; 18(1): 512, 2017 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-28676109

RESUMO

BACKGROUND: Arthropod-borne viruses (arboviruses) transmitted by mosquito vectors cause many important emerging or resurging infectious diseases in humans including dengue, chikungunya and Zika. Understanding the co-evolutionary processes among viruses and vectors is essential for the development of novel transmission-blocking strategies. Episomal viral DNA fragments are produced from arboviral RNA upon infection of mosquito cells and adults. Additionally, sequences from insect-specific viruses and arboviruses have been found integrated into mosquito genomes. RESULTS: We used a bioinformatic approach to analyse the presence, abundance, distribution, and transcriptional activity of integrations from 425 non-retroviral viruses, including 133 arboviruses, across the presently available 22 mosquito genome sequences. Large differences in abundance and types of viral integrations were observed in mosquito species from the same region. Viral integrations are unexpectedly abundant in the arboviral vector species Aedes aegypti and Ae. albopictus, in which they are approximately ~10-fold more abundant than in other mosquito species analysed. Additionally, viral integrations are enriched in piRNA clusters of both the Ae. aegypti and Ae. albopictus genomes and, accordingly, they express piRNAs, but not siRNAs. CONCLUSIONS: Differences in the number of viral integrations in the genomes of mosquito species from the same geographic area support the conclusion that integrations of viral sequences is not dependent on viral exposure, but that lineage-specific interactions exist. Viral integrations are abundant in Ae. aegypti and Ae. albopictus, and represent a thus far underappreciated component of their genomes. Additionally, the genome locations of viral integrations and their production of piRNAs indicate a functional link between viral integrations and the piRNA pathway. These results greatly expand the breadth and complexity of small RNA-mediated regulation and suggest a role for viral integrations in antiviral defense in these two mosquito species.


Assuntos
Aedes/genética , Arbovírus/metabolismo , RNA Interferente Pequeno , Integração Viral , Aedes/metabolismo , Aedes/virologia , Animais , Arbovírus/genética , Culicidae/genética , Culicidae/metabolismo , Culicidae/virologia , DNA Viral , Genoma de Inseto , Genômica , Filogenia
11.
Nucleic Acids Res ; 43(13): 6545-56, 2015 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-26068474

RESUMO

The PIWI-interacting RNA (piRNA) pathway is essential for transposon silencing in many model organisms. Its remarkable efficiency relies on a sophisticated amplification mechanism known as the ping-pong loop. In Alphavirus-infected Aedes mosquitoes, piRNAs with sequence features that suggest ping-pong-dependent biogenesis are produced from viral RNA. The PIWI family in Aedes mosquitoes is expanded when compared to other model organisms, raising the possibility that individual PIWI proteins have functionally diversified in these insects. Here, we show that Piwi5 and Ago3, but none of the other PIWI family members, are essential for piRNA biogenesis from Sindbis virus RNA in infected Aedes aegypti cells. In contrast, the production of piRNAs from transposons relies on a more versatile set of PIWI proteins, some of which do not contribute to viral piRNA biogenesis. These results indicate that functional specialization allows distinct mosquito PIWI proteins to process RNA from different endogenous and exogenous sources.


Assuntos
Arbovírus/genética , Proteínas Argonautas/fisiologia , Elementos de DNA Transponíveis , Proteínas de Insetos/fisiologia , RNA Interferente Pequeno/metabolismo , RNA Viral/metabolismo , Sindbis virus/genética , Aedes/metabolismo , Aedes/virologia , Animais , Proteínas Argonautas/antagonistas & inibidores , Linhagem Celular , Proteínas de Insetos/antagonistas & inibidores , RNA Interferente Pequeno/genética , RNA Viral/genética
12.
Nucleic Acids Res ; 42(13): 8732-44, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24939903

RESUMO

RNA interference (RNAi) is a crucial antiviral defense mechanism in insects, including the major mosquito species that transmit important human viruses. To counteract the potent antiviral RNAi pathway, insect viruses encode RNAi suppressors. However, whether mosquito-specific viruses suppress RNAi remains unclear. We therefore set out to study RNAi suppression by Culex Y virus (CYV), a mosquito-specific virus of the Birnaviridae family that was recently isolated from Culex pipiens mosquitoes. We found that the Culex RNAi machinery processes CYV double-stranded RNA (dsRNA) into viral small interfering RNAs (vsiRNAs). Furthermore, we show that RNAi is suppressed in CYV-infected cells and that the viral VP3 protein is responsible for RNAi antagonism. We demonstrate that VP3 can functionally replace B2, the well-characterized RNAi suppressor of Flock House virus. VP3 was found to bind long dsRNA as well as siRNAs and interfered with Dicer-2-mediated cleavage of long dsRNA into siRNAs. Slicing of target RNAs by pre-assembled RNA-induced silencing complexes was not affected by VP3. Finally, we show that the RNAi-suppressive activity of VP3 is conserved in Drosophila X virus, a birnavirus that persistently infects Drosophila cell cultures. Together, our data indicate that mosquito-specific viruses may encode RNAi antagonists to suppress antiviral RNAi.


Assuntos
Culex/genética , Drosophila melanogaster/genética , Entomobirnavirus/fisiologia , Interferência de RNA , RNA de Cadeia Dupla/metabolismo , RNA Interferente Pequeno/metabolismo , Animais , Células Cultivadas , Culex/virologia , Drosophila melanogaster/virologia , Entomobirnavirus/genética , Entomobirnavirus/metabolismo , Proteínas Virais/metabolismo
13.
Proc Natl Acad Sci U S A ; 109(1): 279-84, 2012 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-22184245

RESUMO

Individual microRNAs (miRNAs) are rapidly down-regulated during conditions of cellular activation and infection, but factors mediating miRNA turnover are poorly understood. Infection of mouse cells with murine cytomegalovirus (MCMV) induces the rapid down-regulation of an antiviral cellular miRNA, miR-27. Here, we identify a transcript produced by MCMV that binds to miR-27 and mediates its degradation. UV-crosslinking and high-throughput sequencing [CRAC (UV-crosslinking and analysis of cDNA)] identified MCMV RNA segments associated with the miRNA-binding protein Argonaute 2 (Ago2). A cluster of hits mapped to a predicted miR-27-binding site in the 3'UTR of the previously uncharacterized ORF, m169. The expression kinetics of the m169 transcript correlated with degradation of miR-27 during infection, and m169 expression inhibited miR-27 functional activity in a reporter assay. siRNA knockdown of m169 demonstrated its requirement for miR-27 degradation following infection and did not affect other host miRNAs. Substitution of the miR-27-binding site in m169 to create complementarity to a different cellular miRNA, miR-24, resulted in down-regulation of only miR-24 following infection. The m169 transcript is cytoplasmic, capped, polyadenylated, and interacts with miRNA-27 through seed pairing: characteristic features of the normal messenger RNA (mRNA) targets of miRNAs. This virus-host interaction reveals a mode of miRNA regulation in which a mRNA directs the degradation of a miRNA. We speculate that RNA-mediated miRNA degradation could be a more general viral strategy for manipulating host cells.


Assuntos
MicroRNAs/antagonistas & inibidores , Muromegalovirus/genética , Regiões 3' não Traduzidas/genética , Animais , Proteínas Argonautas/metabolismo , Sequência de Bases , Sítios de Ligação , Reagentes de Ligações Cruzadas/metabolismo , Citoplasma/metabolismo , DNA Complementar/genética , Regulação da Expressão Gênica/efeitos da radiação , Ensaios de Triagem em Larga Escala , Camundongos , MicroRNAs/genética , MicroRNAs/metabolismo , Dados de Sequência Molecular , Muromegalovirus/efeitos da radiação , Células NIH 3T3 , Nucleotídeos/genética , Estabilidade de RNA/genética , Estabilidade de RNA/efeitos da radiação , Transporte de RNA/efeitos da radiação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Viral/genética , Transcriptoma/genética , Raios Ultravioleta
14.
Cell Mol Life Sci ; 70(19): 3525-44, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23354060

RESUMO

MicroRNAs (miRNAs) are a ubiquitous component of gene regulatory networks that modulate the precise amounts of proteins expressed in a cell. Despite their small size, miRNA genes contain various recognition elements that enable specificity in when, where and to what extent they are expressed. The importance of precise control of miRNA expression is underscored by functional studies in model organisms and by the association between miRNA mis-expression and disease. In the last decade, identification of the pathways by which miRNAs are produced, matured and turned-over has revealed many aspects of their biogenesis that are subject to regulation. Studies in viral systems have revealed a range of mechanisms by which viruses target these pathways through viral proteins or non-coding RNAs in order to regulate cellular gene expression. In parallel, a field of study has evolved around the activation and suppression of antiviral RNA interference (RNAi) by viruses. Virus encoded suppressors of RNAi can impact miRNA biogenesis in cases where miRNA and small interfering RNA pathways converge. Here we review the literature on the mechanisms by which miRNA biogenesis and turnover are regulated in animals and the diverse strategies that viruses use to subvert or inhibit these processes.


Assuntos
MicroRNAs/biossíntese , MicroRNAs/genética , Vírus/genética , Animais , Expressão Gênica , Humanos , MicroRNAs/metabolismo , Vírus/metabolismo
15.
Trans R Soc Trop Med Hyg ; 117(6): 476-478, 2023 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-36637101

RESUMO

BACKGROUND: Glass membrane feeders are used in malaria research for artificial blood feeding. This study investigates the use of Hemotek membrane feeders as a standardized alternative feeding system. METHODS: Hemotek feeders were compared with glass feeders by assessing mosquito feeding rate, imbibed blood meal volume and Plasmodium falciparum infection intensity on mosquito guts. RESULTS: While mosquito feeding rate and blood meal volume were comparable between Hemotek and glass feeders, a loss in transmission was observed using the Hemotek feeder with a conventional collagen membrane. There was no difference in transmission between both feeders when Parafilm was used as the membrane. CONCLUSIONS: Hemotek feeders with a Parafilm membrane can be used as an alternative feeding system for malaria transmission research.


Assuntos
Anopheles , Malária Falciparum , Malária , Animais , Humanos , Plasmodium falciparum , Parafina , Mosquitos Vetores
16.
One Health ; 16: 100490, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36817977

RESUMO

Mosquitoes are vectors for emerging and re-emerging infectious viral diseases of humans, livestock and other animals. In addition to these arthropod-borne (arbo)viruses, mosquitoes are host to an array of insect-specific viruses, collectively referred to as the mosquito virome. Mapping the mosquito virome and understanding if and how its composition modulates arbovirus transmission is critical to understand arboviral disease emergence and outbreak dynamics. In recent years, next-generation sequencing as well as PCR and culture-based methods have been extensively used to identify mosquito-associated viruses, providing insights into virus ecology and evolution. Until now, the large amount of mosquito virome data, specifically those acquired by metagenomic sequencing, has not been comprehensively integrated. We have constructed a searchable database of insect-specific viruses associated with vector mosquitoes from 175 studies, published between October 2000 and February 2022. We identify the most frequently detected and widespread viruses of the Culex, Aedes and Anopheles mosquito genera and report their global distribution. In addition, we highlight the challenges of extracting and integrating published virome data and we propose that a standardized reporting format will facilitate data interpretation and re-use by other scientists. We expect our comprehensive database, summarizing mosquito virome data collected over 20 years, to be a useful resource for future studies.

17.
One Health ; 16: 100565, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37363258

RESUMO

Vector-borne diseases, including those transmitted by mosquitoes, account for more than 17% of infectious diseases worldwide. This number is expected to rise with an increased spread of vector mosquitoes and viruses due to climate change and man-made alterations to ecosystems. Among the most common, medically relevant mosquito-borne infections are those caused by arthropod-borne viruses (arboviruses), especially members of the genera Flavivirus and Alphavirus. Arbovirus infections can cause severe disease in humans, livestock and wildlife. Severe consequences from infections include congenital malformations as well as arthritogenic, haemorrhagic or neuroinvasive disease. Inactivated or live-attenuated vaccines (LAVs) are available for a small number of arboviruses; however there are no licensed vaccines for the majority of these infections. Here we discuss recent developments in pan-arbovirus LAV approaches, from site-directed attenuation strategies targeting conserved determinants of virulence to universal strategies that utilize genome-wide re-coding of viral genomes. In addition to these approaches, we discuss novel strategies targeting mosquito saliva proteins that play an important role in virus transmission and pathogenesis in vertebrate hosts. For rapid pre-clinical evaluations of novel arbovirus vaccine candidates, representative in vitro and in vivo experimental systems are required to assess the desired specific immune responses. Here we discuss promising models to study attenuation of neuroinvasion, neurovirulence and virus transmission, as well as antibody induction and potential for cross-reactivity. Investigating broadly applicable vaccination strategies to target the direct interface of the vertebrate host, the mosquito vector and the viral pathogen is a prime example of a One Health strategy to tackle human and animal diseases.

18.
Methods Mol Biol ; 2509: 3-22, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35796954

RESUMO

In insects, PIWI-interacting (pi)RNAs fulfill versatile regulatory functions inside and outside the germline, including posttranscriptional repression of transposable elements and regulation of gene expression. Canonically, piRNAs act-and have been studied-as a conglomerate of several thousand sequences that cooperatively silence target RNAs. Interestingly, however, an increasing number of studies have demonstrated that individual piRNAs can have profound biological activity as a unique piRNA sequence. Prime examples are the tapiR1 and 2 piRNAs, which mediate target RNA degradation in the developing embryo of Aedes mosquitoes. To study such outstanding individual piRNA species, we describe here a method to interfere with RNA target silencing using antisense oligonucleotides in cell culture as well as in mosquito pre-blastoderm embryos. Although the method has been established for Aedes mosquitoes, it can likely be adapted for use in other invertebrate species as well.


Assuntos
Aedes , Aedes/genética , Animais , Elementos de DNA Transponíveis , Oligonucleotídeos Antissenso , Interferência de RNA , RNA Interferente Pequeno/metabolismo
19.
Antiviral Res ; 202: 105313, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35367280

RESUMO

After decades of being considered non-pathogenic, Zika virus (ZIKV) emerged as an important threat to human health during the epidemic of 2015-2016. ZIKV infections are usually asymptomatic, but can cause Guillain-Barré syndrome in adults and microcephaly in newborns. As there are currently no approved antiviral drugs against ZIKV, we tested anti-ZIKV activity of compounds from the NIH Clinical Collection for which we previously showed antiviral activity against the related dengue virus. One of the top hits from the screen was lacidipine, a 1,4-dihydropyridine calcium antagonist that is approved as an antihypertensive drug. Our data show that lacidipine is antiviral against ZIKV (strain H/PF/2013) in both Vero cells and induced pluripotent stem cell (iPSC)-derived human neural progenitor cells with IC50 values of 3.0 µM and <50 nM, respectively. The antiviral effect was also observed against four other ZIKV strains from the African and Asian lineages. Time-of-addition and replicon assays indicated that lacidipine acts at the post-entry stage of the viral replication cycle, inhibiting viral genome replication. Lacidipine altered the subcellular distribution of free cholesterol and neutral lipids, suggesting that the antiviral effect of lacidipine is mediated by altered trafficking of lipids. Together, these results identify lacidipine as a novel inhibitor of ZIKV replication that likely disturbs trafficking of lipids needed for replication organelle formation.


Assuntos
Bloqueadores dos Canais de Cálcio , Di-Hidropiridinas , Células-Tronco Neurais , Infecção por Zika virus , Animais , Antivirais/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio , Chlorocebus aethiops , Di-Hidropiridinas/farmacologia , Humanos , Recém-Nascido , Lipídeos , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/virologia , Células-Tronco , Células Vero , Replicação Viral , Zika virus , Infecção por Zika virus/tratamento farmacológico
20.
STAR Protoc ; 3(3): 101612, 2022 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-35983169

RESUMO

We describe a protocol for single-cell RNA sequencing of SARS-CoV-2-infected human induced pluripotent stem cell (iPSC)-derived kidney organoids. After inoculation of kidney organoids with virus, we use mechanical and enzymatic disruption to obtain single cell suspensions. Next, we process the organoid-derived cells into sequencing-ready SARS-CoV-2-targeted libraries. Subsequent sequencing analysis reveals changes in kidney cells after virus infection. The protocol was designed for kidney organoids cultured in a 6-well transwell format but can be adapted to organoids with different organ backgrounds. For complete details on the use and execution of this protocol, please refer to Jansen et al. (2022).


Assuntos
COVID-19 , Células-Tronco Pluripotentes Induzidas , Humanos , Rim , Organoides , SARS-CoV-2
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