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1.
Nat Commun ; 11(1): 67, 2020 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-31900422

RESUMO

Certain arenaviruses that circulate in rodent populations can cause life-threatening hemorrhagic fevers when they infect humans. Due to their efficient transmission, arenaviruses pose a severe risk for outbreaks and might be exploited as biological weapons. Effective countermeasures against these viruses are highly desired. Ideally, a single remedy would be effective against many or even all the pathogenic viruses in this family. However, despite the fact that all pathogenic arenaviruses from South America utilize transferrin receptor 1 (TfR1) as a cellular receptor, their viral glycoproteins are highly diversified, impeding efforts to isolate cross-neutralizing antibodies. Here we address this problem using a rational design approach to target TfR1-tropic arenaviruses with high potency and breadth. The pan-reactive molecule is highly effective against all arenaviruses that were tested, offering a universal therapeutic approach. Our design scheme avoids the shortcomings of previous immunoadhesins and can be used to combat other zoonotic pathogens.


Assuntos
Infecções por Arenaviridae/terapia , Arenavirus/imunologia , Imunoterapia , Receptores da Transferrina/química , Receptores da Transferrina/imunologia , Receptores Virais/imunologia , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/genética , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/química , Anticorpos Antivirais/genética , Anticorpos Antivirais/imunologia , Infecções por Arenaviridae/imunologia , Infecções por Arenaviridae/virologia , Arenavirus/química , Arenavirus/genética , Desenho de Fármacos , Humanos , Receptores da Transferrina/genética , Receptores Virais/genética , Proteínas Virais/química , Proteínas Virais/genética , Proteínas Virais/imunologia
2.
Rev Soc Bras Med Trop ; 53: e20190132, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31859943

RESUMO

INTRODUCTION: In Colombia, there is insufficient epidemiological surveillance of zoonotic hemorrhagic viruses. METHODS: We performed a sero-epidemiological study in indigenous populations of Wayuü, Kankuamos, and Tuchin communities using Maciel hantavirus and Junin arenavirus antigens for IgG detection by ELISA. RESULTS: IgG antibodies to hantavirus and arenavirus were found in 5/506 (1%) and 2/506 (0.4%) serum samples, respectively. CONCLUSIONS: Arenavirus and hantavirus circulate in indigenous populations from the Colombian Caribbean region, and the results indicate that the indigenous populations are exposed to these zoonotic agents, with unknown consequences on their health, despite low seroprevalence.


Assuntos
Anticorpos Antivirais/sangue , Infecções por Arenaviridae/epidemiologia , Arenavirus/imunologia , Infecções por Hantavirus/epidemiologia , Hantavirus/imunologia , Imunoglobulina G/sangue , Índios Sul-Americanos , Adulto , Infecções por Arenaviridae/diagnóstico , Colômbia/epidemiologia , Estudos Transversais , Ensaio de Imunoadsorção Enzimática , Feminino , Infecções por Hantavirus/diagnóstico , Humanos , Masculino , Fatores de Risco , Estudos Soroepidemiológicos
3.
Elife ; 82019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31478480

RESUMO

The collapse of iconic, keystone populations of sockeye (Oncorhynchus nerka) and Chinook (Oncorhynchus tshawytscha) salmon in the Northeast Pacific is of great concern. It is thought that infectious disease may contribute to declines, but little is known about viruses endemic to Pacific salmon. Metatranscriptomic sequencing and surveillance of dead and moribund cultured Chinook salmon revealed a novel arenavirus, reovirus and nidovirus. Sequencing revealed two different arenavirus variants which each infect wild Chinook and sockeye salmon. In situ hybridisation localised arenavirus mostly to blood cells. Population surveys of >6000 wild juvenile Chinook and sockeye salmon showed divergent distributions of viruses, implying different epidemiological processes. The discovery in dead and dying farmed salmon of previously unrecognised viruses that are also widely distributed in wild salmon, emphasizes the potential role that viral disease may play in the population dynamics of wild fish stocks, and the threat that these viruses may pose to aquaculture.


Assuntos
Arenavirus/isolamento & purificação , Doenças dos Peixes/virologia , Nidovirales/isolamento & purificação , Reoviridae/isolamento & purificação , Salmão/virologia , Viroses/veterinária , Animais , Arenavirus/classificação , Arenavirus/genética , Células Sanguíneas/virologia , Hibridização In Situ , Metagenômica , Nidovirales/classificação , Nidovirales/genética , Oceano Pacífico , Reoviridae/classificação , Reoviridae/genética , Análise de Sequência de DNA , Transcrição Genética , Viroses/virologia
4.
Antiviral Res ; 167: 68-77, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30953674

RESUMO

Lassa virus (LASV) causes Lassa hemorrhagic fever in humans and poses a significant threat to public health in West Africa. Current therapeutic treatments for Lassa fever are limited, making the development of novel countermeasures an urgent priority. In this study, we identified losmapimod, a p38 mitogen-activated protein kinase (MAPK) inhibitor, from 102 screened compounds as an inhibitor of LASV infection. Losmapimod exerted its inhibitory effect against LASV after p38 MAPK down-regulation, and, interestingly, had no effect on other arenaviruses capable of causing viral hemorrhagic fever. Mechanistic studies showed that losmapimod inhibited LASV entry by affecting the stable signal peptide (SSP)-GP2 subunit interface of the LASV glycoprotein, thereby blocking pH-dependent viral fusion. As an aryl heteroaryl bis-carboxyamide derivative, losmapimod represents a novel chemical scaffold with anti-LASV activity, and it provides a new lead structure for the future development of LASV fusion inhibitors.


Assuntos
Antivirais/farmacologia , Ciclopropanos/farmacologia , Vírus Lassa/efeitos dos fármacos , Piridinas/farmacologia , Internalização do Vírus/efeitos dos fármacos , Animais , Infecções por Arenaviridae/tratamento farmacológico , Arenavirus/efeitos dos fármacos , Linhagem Celular , Chlorocebus aethiops , Reposicionamento de Medicamentos , Inibidores Enzimáticos/farmacologia , Humanos , Febre Lassa/tratamento farmacológico , Febre Lassa/virologia , Células Vero , Proteínas Virais de Fusão/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
5.
Viruses ; 11(3)2019 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-30909570

RESUMO

Lassa virus (LASV) and Mopeia virus (MOPV) are two closely related Old-World mammarenaviruses. LASV causes severe hemorrhagic fever with high mortality in humans, whereas no case of MOPV infection has been reported. Comparing MOPV and LASV is a powerful strategy to unravel pathogenic mechanisms that occur during the course of pathogenic arenavirus infection. We used a yeast two-hybrid approach to identify cell partners of MOPV and LASV Z matrix protein in which two autophagy adaptors were identified, NDP52 and TAX1BP1. Autophagy has emerged as an important cellular defense mechanism against viral infections but its role during arenavirus infection has not been shown. Here, we demonstrate that autophagy is transiently induced by MOPV, but not LASV, in infected cells two days after infection. Impairment of the early steps of autophagy significantly decreased the production of MOPV and LASV infectious particles, whereas a blockade of the degradative steps impaired only MOPV infectious particle production. Our study provides insights into the role played by autophagy during MOPV and LASV infection and suggests that this process could partially explain their different pathogenicity.


Assuntos
Arenavirus/fisiologia , Autofagia , Vírus Lassa/fisiologia , Animais , Arenavirus/patogenicidade , Chlorocebus aethiops , Células HEK293 , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Vírus Lassa/patogenicidade , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Técnicas do Sistema de Duplo-Híbrido , Células Vero
6.
J Virol ; 93(6)2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30626681

RESUMO

Arenaviruses are a large family of emerging enveloped negative-strand RNA viruses that include several causative agents of viral hemorrhagic fevers. For cell entry, human-pathogenic arenaviruses use different cellular receptors and endocytic pathways that converge at the level of acidified late endosomes, where the viral envelope glycoprotein mediates membrane fusion. Inhibitors of arenavirus entry hold promise for therapeutic antiviral intervention and the identification of "druggable" targets is of high priority. Using a recombinant vesicular stomatitis virus pseudotype platform, we identified the clotrimazole-derivative TRAM-34, a highly selective antagonist of the calcium-activated potassium channel KCa3.1, as a specific entry inhibitor for arenaviruses. TRAM-34 specifically blocked entry of most arenaviruses, including hemorrhagic fever viruses, but not Lassa virus and other enveloped viruses. Anti-arenaviral activity was likewise observed with the parental compound clotrimazole and the derivative senicapoc, whereas structurally unrelated KCa3.1 inhibitors showed no antiviral effect. Deletion of KCa3.1 by CRISPR/Cas9 technology did not affect the antiarenaviral effect of TRAM-34, indicating that the observed antiviral effect of clotrimazoles was independent of the known pharmacological target. The drug affected neither virus-cell attachment, nor endocytosis, suggesting an effect on later entry steps. Employing a quantitative cell-cell fusion assay that bypasses endocytosis, we demonstrate that TRAM-34 specifically inhibits arenavirus-mediated membrane fusion. In sum, we uncover a novel antiarenaviral action of clotrimazoles that currently undergo in vivo evaluation in the context of other human diseases. Their favorable in vivo toxicity profiles and stability opens the possibility to repurpose clotrimazole derivatives for therapeutic intervention against human-pathogenic arenaviruses.IMPORTANCE Emerging human-pathogenic arenaviruses are causative agents of severe hemorrhagic fevers with high mortality and represent serious public health problems. The current lack of a licensed vaccine and the limited treatment options makes the development of novel antiarenaviral therapeutics an urgent need. Using a recombinant pseudotype platform, we uncovered that clotrimazole drugs, in particular TRAM-34, specifically inhibit cell entry of a range of arenaviruses, including important emerging human pathogens, with the exception of Lassa virus. The antiviral effect was independent of the known pharmacological drug target and involved inhibition of the unusual membrane fusion mechanism of arenaviruses. TRAM-34 and its derivatives currently undergo evaluation against a number of human diseases and show favorable toxicity profiles and high stability in vivo Our study provides the basis for further evaluation of clotrimazole derivatives as antiviral drug candidates. Their advanced stage of drug development will facilitate repurposing for therapeutic intervention against human-pathogenic arenaviruses.


Assuntos
Antivirais/farmacologia , Arenavirus/efeitos dos fármacos , Clotrimazol/farmacologia , Fusão de Membrana/efeitos dos fármacos , Células A549 , Animais , Infecções por Arenaviridae/tratamento farmacológico , Linhagem Celular , Linhagem Celular Tumoral , Chlorocebus aethiops , Endocitose/efeitos dos fármacos , Células HEK293 , Células HeLa , Febres Hemorrágicas Virais/tratamento farmacológico , Febres Hemorrágicas Virais/virologia , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Vírus Lassa/efeitos dos fármacos , Células Vero , Proteínas do Envelope Viral/metabolismo , Ligação Viral/efeitos dos fármacos , Internalização do Vírus/efeitos dos fármacos
7.
Curr Opin Virol ; 34: 18-28, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30497052

RESUMO

Next-generation sequencing technologies have revolutionized our knowledge of virus diversity and evolution. In the case of arenaviruses, which are the focus of this review, metagenomic/metatranscriptomic approaches identified reptile-infecting and fish-infecting viruses, also showing that bi-segmented genomes are not a universal feature of the Arenaviridae family. Novel mammarenaviruses were described, allowing inference of their geographic origin and evolutionary dynamics. Extensive sequencing of Lassa virus (LASV) genomes revealed the zoonotic nature of most human infections and a Nigerian origin of LASV, which subsequently spread westward. Future efforts will likely identify many more arenaviruses and hopefully provide insight into the ultimate origin of the family, the pathogenic potential of its members, as well as the determinants of their geographic distribution.


Assuntos
Arenavirus/genética , Evolução Molecular , Variação Genética , Genoma Viral , Animais , Infecções por Arenaviridae/transmissão , Peixes/virologia , Sequenciamento de Nucleotídeos em Larga Escala , Interações entre Hospedeiro e Microrganismos , Humanos , Répteis/virologia , Zoonoses/transmissão , Zoonoses/virologia
8.
PLoS Pathog ; 14(11): e1007415, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30427944

RESUMO

The family Arenaviridae comprises three genera, Mammarenavirus, Reptarenavirus and the most recently added Hartmanivirus. Arenaviruses have a bisegmented genome with ambisense coding strategy. For mammarenaviruses and reptarenaviruses the L segment encodes the Z protein (ZP) and the RNA-dependent RNA polymerase, and the S segment encodes the glycoprotein precursor and the nucleoprotein. Herein we report the full length genome and characterization of Haartman Institute snake virus-1 (HISV-1), the putative type species of hartmaniviruses. The L segment of HISV-1 lacks an open-reading frame for ZP, and our analysis of purified HISV-1 particles by SDS-PAGE and electron microscopy further support the lack of ZP. Since we originally identified HISV-1 in co-infection with a reptarenavirus, one could hypothesize that co-infecting reptarenavirus provides the ZP to complement HISV-1. However, we observed that co-infection does not markedly affect the amount of hartmanivirus or reptarenavirus RNA released from infected cells in vitro, indicating that HISV-1 does not benefit from reptarenavirus ZP. Furthermore, we succeeded in generating a pure HISV-1 isolate showing the virus to replicate without ZP. Immunofluorescence and ultrastructural studies demonstrate that, unlike reptarenaviruses, HISV-1 does not produce the intracellular inclusion bodies typical for the reptarenavirus-induced boid inclusion body disease (BIBD). While we observed HISV-1 to be slightly cytopathic for cultured boid cells, the histological and immunohistological investigation of HISV-positive snakes showed no evidence of a pathological effect. The histological analyses also revealed that hartmaniviruses, unlike reptarenaviruses, have a limited tissue tropism. By nucleic acid sequencing, de novo genome assembly, and phylogenetic analyses we identified additional four hartmanivirus species. Finally, we screened 71 individuals from a collection of snakes with BIBD by RT-PCR and found 44 to carry hartmaniviruses. These findings suggest that harmaniviruses are common in captive snake populations, but their relevance and pathogenic potential needs yet to be revealed.


Assuntos
Arenavirus/classificação , Arenavirus/genética , Animais , Arenaviridae/genética , Infecções por Arenaviridae/virologia , Sequência de Bases , Boidae/virologia , Linhagem Celular , Corpos de Inclusão Viral/patologia , Filogenia , RNA Replicase/genética , RNA Viral/genética , Proteínas Virais/genética
9.
Antiviral Res ; 160: 87-93, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30339847

RESUMO

The family Arenaviridae consists of numerous enveloped RNA viruses with ambisense coding strategies. Eight arenaviruses, including Lassa virus, are known to cause severe and fatal viral hemorrhagic fever (VHF) in humans, yet vaccines and treatments for disease caused by arenaviruses are very limited. In this study, we screened a natural product library consisting of 131 compounds and identified tangeretin, a polymethoxylated flavone widely present in citrus fruit peels, as a Lassa virus entry inhibitor that blocks viral fusion. Further analyses demonstrated the efficacy of tangeretin against seven other VHF-causing arenaviruses, suggesting that this compound, which has a history of medical usage, could be used to develop an effective therapeutic to treat infection and disease caused by Lassa virus and related viruses.


Assuntos
Antivirais/farmacologia , Arenavirus/efeitos dos fármacos , Citrus/química , Flavonas/farmacologia , Internalização do Vírus/efeitos dos fármacos , Antivirais/isolamento & purificação , Arenavirus/fisiologia , Produtos Biológicos/isolamento & purificação , Produtos Biológicos/farmacologia , Avaliação Pré-Clínica de Medicamentos , Flavonas/isolamento & purificação
10.
Artigo em Inglês | MEDLINE | ID: mdl-30087859

RESUMO

An important step in the initiation of the innate immune response to virus infection is the recognition of non-self, viral RNA, including double-stranded RNA (dsRNA), by cytoplasmic pattern recognition receptors (PRRs). For many positive-sense RNA viruses and DNA viruses, the production of viral dsRNA, and the interaction of viral dsRNA and PRRs are well characterized. However, for negative-sense RNA viruses, viral dsRNA was thought to be produced at low to undetectable levels and PRR recognition of viral dsRNA is still largely unclear. In the case of arenaviruses, the nucleocaspid protein (NP) has been identified to contain an exoribonuclease activity that preferentially degrades dsRNA in biochemical studies. Nevertheless, pathogenic New World (NW) arenavirus infections readily induce an interferon (IFN) response in a RIG-I dependent manner, and also activate the dsRNA-dependent Protein Kinase R (PKR). To better understand the innate immune response to pathogenic arenavirus infection, we used a newly identified dsRNA-specific antibody that efficiently detects viral dsRNA in negative-sense RNA virus infected cells. dsRNA was detected in NW arenavirus infected cells colocalizing with virus NP in immunofluorescence assay. Importantly, the dsRNA signals also colocalized with cytoplasmic PRRs, namely, PKR, RIG-I and MDA-5, as well as with the phosphorylated, activated form of PKR in infected cells. Our data clearly demonstrate the PRR recognition of dsRNA and their activation in NW arenavirus infected cells. These findings provide new insights into the interaction between NW arenaviruses and the host innate immune response.


Assuntos
Arenavirus/crescimento & desenvolvimento , Células Epiteliais/imunologia , Células Epiteliais/virologia , Interações Hospedeiro-Patógeno , RNA de Cadeia Dupla/análise , RNA Viral/análise , Receptores de Reconhecimento de Padrão/análise , Células A549 , Proteína DEAD-box 58/análise , Humanos , Helicase IFIH1 Induzida por Interferon/análise , Microscopia Confocal , Microscopia de Fluorescência , eIF-2 Quinase/análise
11.
Sci Rep ; 8(1): 12179, 2018 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-30111770

RESUMO

Immune responses are critical for defense against pathogens. However, prolonged viral infection can result in defective T cell immunity, leading to chronic viral infection. We studied immune activation in response to arenavirus infection during cholestasis using bile duct ligation (BDL). We monitored T cell responses, virus load and liver pathology markers after infection with lymphocytic choriomeningitis virus (LCMV). BDL mice failed to induce protective anti-viral immunity against LCMV and consequently exhibited chronic viral infection. BDL mice exhibited reduced anti-viral T cell immunity as well as reduced type 1 interferon production early after LCMV infection. Consistently, the presence of serum from BDL mice reduced the responsiveness of dendritic cell (DC) and T cell cultures when compared to Sham controls. Following fractionation and mass spectrometry analyses of sera, we identified several serum factors to be upregulated following BDL including bilirubin, bile acids, 78 kDa Glucose regulated protein (GRP78) and liver enzymes. Bilirubin and GRP78 were capable of inhibiting DC and T cell activation. In this work, we demonstrate that liver damage mediated by cholestasis results in defective immune induction following arenavirus infection.


Assuntos
Infecções por Arenaviridae/imunologia , Colestase/imunologia , Hepatopatias/imunologia , Fígado/imunologia , Animais , Infecções por Arenaviridae/patologia , Arenavirus/imunologia , Ductos Biliares/imunologia , Ductos Biliares/patologia , Linfócitos T CD4-Positivos/imunologia , Colestase/patologia , Células Dendríticas/imunologia , Interferon Tipo I/imunologia , Fígado/patologia , Hepatopatias/patologia , Ativação Linfocitária/imunologia , Coriomeningite Linfocítica/imunologia , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais
12.
Parasit Vectors ; 11(1): 416, 2018 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-30005641

RESUMO

BACKGROUND: Lassa fever, killing thousands of people annually, is the most reported viral zoonotic disease in Nigeria. Recently, different rodent species carrying diverse lineages of the Lassa virus (LASV) in addition to a novel Mobala-like genetic sequence were detected within the country. Here, screening 906 small mammal specimens from 11 localities for IgG antibodies and incorporating previous PCR detection data involving the same populations, we further describe arenavirus prevalence across Nigeria in relation to host species and geographical location. METHODS: Small mammals were trapped during the period 2011-2015 according to geographical location (endemic and non-endemic zones for Lassa fever), season (rainy and dry seasons between 2011 and 2012 for certain localities) and habitat (indoors, peridomestic settings and sylvatic vegetation). Identification of animal specimens from genera such as Mastomys and Mus (Nannomys) was assisted by DNA sequencing. Small mammals were tested for LASV IgG antibody using an indirect immunofluorescence assay (IFA). RESULTS: Small mammals were infected in both the endemic and non-endemic zones for Lassa fever, with a wider range of species IgG-positive (n = 8) than those which had been previously detected to be PCR-positive (n = 3). IgG-positive species, according to number of infected individuals, were Mastomys natalensis (n = 40), Mastomys erythroleucus (n = 15), Praomys daltoni (n = 6), Mus baoulei (n = 5), Rattus rattus (n = 2), Crocidura spp. (n = 2), Mus minutoides (n = 1) and Praomys misonnei (n = 1). Multimammate mice (Mastomys natalensis and M. erythroleucus) were the most ubiquitously infected, with animals testing positive by either PCR or IgG in 7 out of the 11 localities sampled. IgG prevalence in M. natalensis ranged from 1% in Abagboro, 17-36 % in Eguare Egoro, Ekpoma and Ngel Nyaki, up to 52 % in Mayo Ranewo. Prevalence according to locality, season and age was not, however, statistically significant for M. natalensis in Eguare Egoro and Ekpoma, localities that were sampled longitudinally. CONCLUSIONS: Overall, our study demonstrates that arenavirus occurrence is probably more widely distributed geographically and in extent of host taxa than is currently realized. This expanded scope should be taken into consideration in Lassa fever control efforts. Further sampling should also be carried out to isolate and characterize potential arenaviruses present in small mammal populations we found to be seropositive.


Assuntos
Anticorpos Antivirais/sangue , Infecções por Arenaviridae/sangue , Infecções por Arenaviridae/veterinária , Arenavirus/fisiologia , Doenças dos Roedores/sangue , Doenças dos Roedores/epidemiologia , Animais , Infecções por Arenaviridae/epidemiologia , Infecções por Arenaviridae/virologia , Arenavirus/imunologia , Reservatórios de Doenças/virologia , Geografia , Insetívoros/virologia , Vírus Lassa/imunologia , Vírus Lassa/fisiologia , Camundongos , Nigéria/epidemiologia , Prevalência , RNA Viral/genética , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Doenças dos Roedores/virologia , Roedores/virologia , Estudos Soroepidemiológicos
13.
Emerg Microbes Infect ; 7(1): 120, 2018 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-29959319

RESUMO

Mammarenavirus RNA was detected in Musser's bristly mouse (Neacomys musseri) from the Amazon region, and this detection indicated that rodents were infected with a novel mammarenavirus, with the proposed name Xapuri virus (XAPV), which is phylogenetically related to New World Clade B and Clade C viruses. XAPV may represent the first natural reassortment of the Arenaviridae family and a new unrecognized clade within the Tacaribe serocomplex group.


Assuntos
Arenavirus/classificação , Arenavirus/genética , Arenavirus do Novo Mundo/genética , Variação Genética , Vírus Reordenados/genética , Animais , Infecções por Arenaviridae/epidemiologia , Infecções por Arenaviridae/virologia , Brasil/epidemiologia , Evolução Molecular , Genoma Viral , Geografia , Conformação de Ácido Nucleico , Filogenia , RNA Viral/química , RNA Viral/genética , Roedores
14.
PLoS Pathog ; 14(7): e1007125, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-30001425

RESUMO

Several arenaviruses cause hemorrhagic fever (HF) diseases that are associated with high morbidity and mortality in humans. Accordingly, HF arenaviruses have been listed as top-priority emerging diseases for which countermeasures are urgently needed. Because arenavirus nucleoprotein (NP) plays critical roles in both virus multiplication and immune-evasion, we used an unbiased proteomic approach to identify NP-interacting proteins in human cells. DDX3, a DEAD-box ATP-dependent-RNA-helicase, interacted with NP in both NP-transfected and virus-infected cells. Importantly, DDX3 deficiency compromised the propagation of both Old and New World arenaviruses, including the HF arenaviruses Lassa and Junin viruses. The DDX3 role in promoting arenavirus multiplication associated with both a previously un-recognized DDX3 inhibitory role in type I interferon production in arenavirus infected cells and a positive DDX3 effect on arenavirus RNA synthesis that was dependent on its ATPase and Helicase activities. Our results uncover novel mechanisms used by arenaviruses to exploit the host machinery and subvert immunity, singling out DDX3 as a potential host target for developing new therapies against highly pathogenic arenaviruses.


Assuntos
Infecções por Arenaviridae/metabolismo , RNA Helicases DEAD-box/metabolismo , Interações Hospedeiro-Patógeno/fisiologia , Evasão da Resposta Imune/imunologia , Replicação Viral/fisiologia , Infecções por Arenaviridae/imunologia , Arenavirus , Linhagem Celular , RNA Helicases DEAD-box/imunologia , Humanos , Interferon Tipo I/biossíntese , Interferon Tipo I/imunologia , Proteínas do Core Viral/imunologia , Proteínas do Core Viral/metabolismo
16.
Ecohealth ; 15(3): 695-704, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29796719

RESUMO

Rodent-borne hanta- and arenaviruses are an emerging public health threat in Europe; however, their circulation in human populations is usually underestimated since most infections are asymptomatic. Compared to other European countries, Italy is considered 'low risk' for these viruses, yet in the Province of Trento, two pathogenic hantaviruses (Puumala and Dobrava-Belgrade virus) and one arenavirus (Lymphocytic Choriomeningitis Virus) are known to circulate in rodent reservoirs. In this paper, we performed a follow-up serological screening in humans to detect variation in the prevalence of these three viruses compared to previous analyses carried out in 2002. We also used a statistical model to link seropositivity to risk factors such as occupational exposure, cutting firewood, hunting, collecting mushrooms, having a garden and owning a woodshed, a dog or a companion rodent. We demonstrate a significant increase in the seroprevalence of all three target viruses between 2002 and 2015, but no risk factors that we considered were significantly correlated with this increase. We conclude that the general exposure of residents in the Alps to these viruses has probably increased during the last decade. These results provide an early warning to public health authorities, and we suggest more detailed diagnostic and clinical investigations on suspected cases.


Assuntos
Anticorpos Antivirais/sangue , Arenavirus/isolamento & purificação , Vetores de Doenças , Hantavirus/isolamento & purificação , Roedores/virologia , Zoonoses/epidemiologia , Animais , Europa (Continente)/epidemiologia , Humanos , Itália/epidemiologia , Medição de Risco , Estudos Soroepidemiológicos
17.
Curr Opin Virol ; 31: 52-58, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29843991

RESUMO

The structure of a prefusion arenavirus GPC was enigmatic for many years, owing to the metastable and non-covalent nature of the association between the receptor binding and fusion subunits. Recent engineering efforts to stabilize the glycoprotein of the Old World arenavirus Lassa in a native, yet cleaved state, allowed the first structure of any arenavirus prefusion GPC trimer to be determined. Comparison of this structure with the structures of other arenavirus glycoprotein subunits reveals surprising findings: that the receptor binding subunit, GP1, of Lassa virus is conformationally labile, while the GP1 subunit of New World arenaviruses is not, and that the arenavirus GPC adopts a trimeric state unlike other glycoproteins with similar fusion machinery. Structural analysis, combined with recent biochemical data regarding antibody epitopes and receptor binding requirements, provides a basis for rational vaccine design.


Assuntos
Epitopos/imunologia , Glicoproteínas/química , Glicoproteínas/metabolismo , Vírus Lassa/química , Arenavirus/metabolismo , Humanos , Vírus Lassa/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína , Proteínas do Envelope Viral/metabolismo , Internalização do Vírus
18.
J Virol ; 92(13)2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29669840

RESUMO

RIG-I is a major cytoplasmic sensor of viral pathogen-associated molecular pattern (PAMP) RNA and induces type I interferon (IFN) production upon viral infection. A double-stranded RNA (dsRNA)-binding protein, PACT, plays an important role in potentiating RIG-I function. We have shown previously that arenaviral nucleoproteins (NPs) suppress type I IFN production via their RNase activity to degrade PAMP RNA. We report here that NPs of arenaviruses block the PACT-induced enhancement of RIG-I function to mediate type I IFN production and that this inhibition is dependent on the RNase function of NPs, which is different from that of a known mechanism of other viral proteins to abolish the interaction between PACT and RIG-I. To understand the biological roles of PACT and RIG-I in authentic arenavirus infection, we analyze growth kinetics of recombinant Pichinde virus (PICV), a prototypical arenavirus, in RIG-I knockout (KO) and PACT KO mouse embryonic fibroblast (MEF) cells. Wild-type (WT) PICV grew at higher titers in both KO MEF lines than in normal MEFs, suggesting the important roles of these cellular proteins in restricting virus replication. PICV carrying the NP RNase catalytically inactive mutation could not grow in normal MEFs but could replicate to some extent in both KO MEF lines. The level of virus growth was inversely correlated with the amount of type I IFNs produced. These results suggest that PACT plays an important role in potentiating RIG-I function to produce type I IFNs in order to restrict arenavirus replication and that viral NP RNase activity is essential for optimal viral replication by suppressing PACT-induced RIG-I activation.IMPORTANCE We report here a new role of the nucleoproteins of arenaviruses that can block type I IFN production via their specific inhibition of the cellular protein sensors of virus infection (RIG-I and PACT). Our results suggest that PACT plays an important role in potentiating RIG-I function to produce type I IFNs in order to restrict arenavirus replication. This new knowledge can be exploited for the development of novel antiviral treatments and/or vaccines against some arenaviruses that can cause severe and lethal hemorrhagic fever diseases in humans.


Assuntos
Arenavirus/patogenicidade , Interações Hospedeiro-Patógeno , Interferon Tipo I/metabolismo , Nucleoproteínas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Receptores do Ácido Retinoico/metabolismo , Proteínas Virais/metabolismo , Infecções por Arenaviridae/genética , Infecções por Arenaviridae/metabolismo , Infecções por Arenaviridae/virologia , Células HEK293 , Humanos , Nucleoproteínas/genética , Vírus Pichinde/fisiologia , Proteínas de Ligação a RNA/genética , Receptores do Ácido Retinoico/genética , Proteínas Virais/genética , Replicação Viral
19.
J Mol Biol ; 430(13): 1839-1852, 2018 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-29705070

RESUMO

Viral hemorrhagic fevers caused by emerging RNA viruses of the Arenavirus family are among the most devastating human diseases. Climate change, global trade, and increasing urbanization promote the emergence and re-emergence of these human pathogenic viruses. Emerging pathogenic arenaviruses are of zoonotic origin and reservoir-to-human transmission is crucial for spillover into human populations. Host cell attachment and entry are the first and most fundamental steps of every virus infection and represent major barriers for zoonotic transmission. During host cell invasion, viruses critically depend on cellular factors, including receptors, co-receptors, and regulatory proteins of endocytosis. An in-depth understanding of the complex interaction of a virus with cellular factors implicated in host cell entry is therefore crucial to predict the risk of zoonotic transmission, define the tissue tropism, and assess disease potential. Over the past years, investigation of the molecular and cellular mechanisms underlying host cell invasion of human pathogenic arenaviruses uncovered remarkable viral strategies and provided novel insights into viral adaptation and virus-host co-evolution that will be covered in the present review.


Assuntos
Infecções por Arenaviridae/virologia , Arenavirus/fisiologia , Zoonoses/virologia , Animais , Infecções por Arenaviridae/transmissão , Arenavirus/genética , Interações entre Hospedeiro e Microrganismos , Humanos , Tropismo Viral , Ligação Viral , Internalização do Vírus , Zoonoses/transmissão
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