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1.
NPJ Vaccines ; 9(1): 134, 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39085247

RESUMO

In 2022, a genotype IV (GIV) strain of Japanese encephalitis virus (JEV) caused an unprecedented and widespread outbreak of disease in pigs and humans in Australia. As no veterinary vaccines against JEV are approved in Australia and all current approved human and veterinary vaccines are derived from genotype (G) III JEV strains, we used the recently described insect-specific Binjari virus (BinJV) chimeric flavivirus vaccine technology to produce a JEV GIV vaccine candidate. Herein we describe the production of a chimeric virus displaying the structural prM and E proteins of a JEV GIV isolate obtained from a stillborn piglet (JEVNSW/22) in the genomic backbone of BinJV (BinJ/JEVNSW/22-prME). BinJ/JEVNSW/22-prME was shown to be antigenically indistinguishable from the JEVNSW/22 parental virus by KD analysis and a panel of JEV-reactive monoclonal antibodies in ELISA. BinJ/JEVNSW/22-prME replicated efficiently in C6/36 cells, reaching titres of >107 infectious units/mL - an important attribute for vaccine manufacture. As expected, BinJ/JEVNSW/22-prME failed to replicate in a variety of vertebrate cells lines. When used to immunise mice, the vaccine induced a potent virus neutralising response against JEVNSW/22 and to GII and GIII JEV strains. The BinJ/JEVNSW/22-prME vaccine provided complete protection against lethal challenge with JEVNSW/22, whilst also providing partial protection against viraemia and disease for the related Murray Valley encephalitis virus. Our results demonstrate that BinJ/JEVNSW/22-prME is a promising vaccine candidate against JEV.

2.
Nat Aging ; 3(12): 1561-1575, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37957361

RESUMO

Aging is a major risk factor for neurodegenerative diseases, and coronavirus disease 2019 (COVID-19) is linked to severe neurological manifestations. Senescent cells contribute to brain aging, but the impact of virus-induced senescence on neuropathologies is unknown. Here we show that senescent cells accumulate in aged human brain organoids and that senolytics reduce age-related inflammation and rejuvenate transcriptomic aging clocks. In postmortem brains of patients with severe COVID-19 we observed increased senescent cell accumulation compared with age-matched controls. Exposure of human brain organoids to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induced cellular senescence, and transcriptomic analysis revealed a unique SARS-CoV-2 inflammatory signature. Senolytic treatment of infected brain organoids blocked viral replication and prevented senescence in distinct neuronal populations. In human-ACE2-overexpressing mice, senolytics improved COVID-19 clinical outcomes, promoted dopaminergic neuron survival and alleviated viral and proinflammatory gene expression. Collectively our results demonstrate an important role for cellular senescence in driving brain aging and SARS-CoV-2-induced neuropathology, and a therapeutic benefit of senolytic treatments.


Assuntos
COVID-19 , Humanos , Camundongos , Animais , Idoso , Senoterapia , SARS-CoV-2 , Envelhecimento , Encéfalo
3.
Sci Adv ; 8(48): eadd8095, 2022 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-36449607

RESUMO

All flaviviruses, including Zika virus, produce noncoding subgenomic flaviviral RNA (sfRNA), which plays an important role in viral pathogenesis. However, the exact mechanism of how sfRNA enables viral evasion of antiviral response is not well defined. Here, we show that sfRNA is required for transplacental virus dissemination in pregnant mice and subsequent fetal brain infection. We also show that sfRNA promotes apoptosis of neural progenitor cells in human brain organoids, leading to their disintegration. In infected human placental cells, sfRNA inhibits multiple antiviral pathways and promotes apoptosis, with signal transducer and activator of transcription 1 (STAT1) identified as a key shared factor. We further show that the production of sfRNA leads to reduced phosphorylation and nuclear translocation of STAT1 via a mechanism that involves sfRNA binding to and stabilizing viral protein NS5. Our results suggest the cooperation between viral noncoding RNA and a viral protein as a novel strategy for counteracting antiviral responses.


Assuntos
Infecção por Zika virus , Zika virus , Gravidez , Humanos , Feminino , Animais , Camundongos , Fosforilação , Proteínas Virais , Placenta , RNA Viral/genética , Antivirais , RNA não Traduzido/genética , Infecção por Zika virus/genética , Fator de Transcrição STAT1/genética
4.
Vaccines (Basel) ; 10(5)2022 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-35632447

RESUMO

The COVID-19 pandemic is the biggest public health threat facing the world today. Multiple vaccines have been approved; however, the emergence of viral variants such as the recent Omicron raises the possibility of booster doses to achieve adequate protection. In Brazil, the CoronaVac (Sinovac, Beijing, China) vaccine was used; however, it is important to assess the immune response to this vaccine over time. This study aimed to monitor the anti-SARS-CoV-2 antibody responses in those immunized with CoronaVac and SARS-CoV-2 infected individuals. Samples were collected between August 2020 and August 2021. Within the vaccinated cohort, some individuals had a history of infection by SARS-CoV-2 prior to immunization, while others did not. We analyzed RBD-specific and neutralizing-antibodies. Anti-RBD antibodies were detected in both cohorts, with a peak between 45-90 days post infection or vaccination, followed by a steady decline over time. In those with a previous history of COVID-19, a higher, longer, more persistent response was observed. This trend was mirrored in the neutralization assays, where infection, followed by immunization, resulted in higher, longer lasting responses which were conditioned on the presence of levels of RBD antibodies right before the vaccination. This supports the necessity of booster doses of CoronaVac in due course to prevent serious disease.

5.
Front Microbiol ; 12: 625136, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33643253

RESUMO

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been identified as the causative agent of coronavirus disease 2019 and is capable of human-to-human transmission and rapid global spread. The rapid emergence and global spread of SARS-CoV-2 has encouraged the establishment of a rapid, sensitive, and reliable viral detection and quantification methodology. Here, we present an alternative assay, termed immuno-plaque assay (iPA), which utilizes a combination of plaque assay and immunofluorescence techniques. We have extensively optimized the conditions for SARS-CoV-2 infection and demonstrated the great flexibility of iPA detection using several antibodies and dual-probing with two distinct epitope-specific antibodies. In addition, we showed that iPA could be utilized for ultra-high-throughput viral titration and neutralization assay within 24 h and is amenable to a 384-well format. These advantages will significantly accelerate SARS-CoV-2 research outcomes during this pandemic period.

6.
Science ; 371(6525): 190-194, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33414219

RESUMO

There are no approved flaviviral therapies and the development of vaccines against flaviruses has the potential of being undermined by antibody-dependent enhancement (ADE). The flavivirus nonstructural protein 1 (NS1) is a promising vaccine antigen with low ADE risk but has yet to be explored as a broad-spectrum therapeutic antibody target. Here, we provide the structural basis of NS1 antibody cross-reactivity through cocrystallization of the antibody 1G5.3 with NS1 proteins from dengue and Zika viruses. The 1G5.3 antibody blocks multi-flavivirus NS1-mediated cell permeability in disease-relevant cell lines, and therapeutic application of 1G5.3 reduces viremia and improves survival in dengue, Zika, and West Nile virus murine models. Finally, we demonstrate that 1G5.3 protection is independent of effector function, identifying the 1G5.3 epitope as a key site for broad-spectrum antiviral development.


Assuntos
Anticorpos Neutralizantes/química , Anticorpos Antivirais/química , Vírus da Dengue/imunologia , Proteínas não Estruturais Virais/imunologia , Vírus do Nilo Ocidental/imunologia , Zika virus/imunologia , Animais , Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/uso terapêutico , Células CHO , Linhagem Celular , Cricetulus , Reações Cruzadas , Dengue/prevenção & controle , Dengue/terapia , Modelos Animais de Doenças , Humanos , Camundongos , Domínios Proteicos , Proteínas não Estruturais Virais/química , Viremia/terapia , Febre do Nilo Ocidental/prevenção & controle , Febre do Nilo Ocidental/terapia , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/terapia
7.
Nat Commun ; 12(1): 3431, 2021 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-34103499

RESUMO

The current COVID-19 pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We demonstrate that despite the large size of the viral RNA genome (~30 kb), infectious full-length cDNA is readily assembled in vitro by a circular polymerase extension reaction (CPER) methodology without the need for technically demanding intermediate steps. Overlapping cDNA fragments are generated from viral RNA and assembled together with a linker fragment containing CMV promoter into a circular full-length viral cDNA in a single reaction. Transfection of the circular cDNA into mammalian cells results in the recovery of infectious SARS-CoV-2 virus that exhibits properties comparable to the parental virus in vitro and in vivo. CPER is also used to generate insect-specific Casuarina virus with ~20 kb genome and the human pathogens Ross River virus (Alphavirus) and Norovirus (Calicivirus), with the latter from a clinical sample. Additionally, reporter and mutant viruses are generated and employed to study virus replication and virus-receptor interactions.


Assuntos
Genética Reversa , SARS-CoV-2/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Chlorocebus aethiops , Culicidae/virologia , Furina/metabolismo , Genoma Viral , Células HEK293 , Humanos , Camundongos , Mutação/genética , Células NIH 3T3 , Reação em Cadeia da Polimerase , Células RAW 264.7 , Receptores Virais/metabolismo , Células Vero , Proteínas Virais/química , Replicação Viral
8.
Nat Commun ; 11(1): 2205, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-32371874

RESUMO

Flaviviruses, including Zika virus (ZIKV), utilise host mRNA degradation machinery to produce subgenomic flaviviral RNA (sfRNA). In mammalian hosts, this noncoding RNA facilitates replication and pathogenesis of flaviviruses by inhibiting IFN-signalling, whereas the function of sfRNA in mosquitoes remains largely elusive. Herein, we conduct a series of in vitro and in vivo experiments to define the role of ZIKV sfRNA in infected Aedes aegypti employing viruses deficient in production of sfRNA. We show that sfRNA-deficient viruses have reduced ability to disseminate and reach saliva, thus implicating the role for sfRNA in productive infection and transmission. We also demonstrate that production of sfRNA alters the expression of mosquito genes related to cell death pathways, and prevents apoptosis in mosquito tissues. Inhibition of apoptosis restored replication and transmission of sfRNA-deficient mutants. Hence, we propose anti-apoptotic activity of sfRNA as the mechanism defining its role in ZIKV transmission.


Assuntos
Aedes/genética , Apoptose/genética , Mosquitos Vetores/genética , RNA Viral/genética , Infecção por Zika virus/genética , Zika virus/genética , Aedes/citologia , Aedes/virologia , Animais , Células Cultivadas , Chlorocebus aethiops , Regulação da Expressão Gênica , Humanos , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Mosquitos Vetores/citologia , Mosquitos Vetores/virologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA não Traduzido/genética , RNA não Traduzido/metabolismo , RNA Viral/metabolismo , Células Vero , Replicação Viral/genética , Zika virus/fisiologia , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia
9.
Nat Microbiol ; 4(5): 876-887, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30886357

RESUMO

Arboviruses cycle between, and replicate in, both invertebrate and vertebrate hosts, which for Zika virus (ZIKV) involves Aedes mosquitoes and primates1. The viral determinants required for replication in such obligate hosts are under strong purifying selection during natural virus evolution, making it challenging to resolve which determinants are optimal for viral fitness in each host. Herein we describe a deep mutational scanning (DMS) strategy2-5 whereby a viral cDNA library was constructed containing all codon substitutions in the C-terminal 204 amino acids of ZIKV envelope protein (E). The cDNA library was transfected into C6/36 (Aedes) and Vero (primate) cells, with subsequent deep sequencing and computational analyses of recovered viruses showing that substitutions K316Q and S461G, or Q350L and T397S, conferred substantial replicative advantages in mosquito and primate cells, respectively. A 316Q/461G virus was constructed and shown to be replication-defective in mammalian cells due to severely compromised virus particle formation and secretion. The 316Q/461G virus was also highly attenuated in human brain organoids, and illustrated utility as a vaccine in mice. This approach can thus imitate evolutionary selection in a matter of days and identify amino acids key to the regulation of virus replication in specific host environments.


Assuntos
Análise Mutacional de DNA/métodos , Tropismo Viral , Infecção por Zika virus/virologia , Zika virus/fisiologia , Aedes/virologia , Animais , Evolução Biológica , Chlorocebus aethiops , Feminino , Especificidade de Hospedeiro , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Mosquitos Vetores/virologia , Mutação , Seleção Genética , Células Vero , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo , Replicação Viral , Zika virus/química , Zika virus/genética
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