RESUMO
Host defense systems employ posttranslational modifications to protect against invading pathogens. Here, we found that protein inhibitor of activated STAT 1 (PIAS1) interacts with the nucleoprotein (NP), polymerase basic protein 1 (PB1), and polymerase basic protein 2 (PB2) of influenza A virus (IAV). Lentiviral-mediated stable overexpression of PIAS1 dramatically suppressed the replication of IAV, whereas siRNA knockdown or CRISPR/Cas9 knockout of PIAS1 expression significantly increased virus growth. The expression of PIAS1 was significantly induced upon IAV infection in both cell culture and mice, and PIAS1 was involved in the overall increase in cellular SUMOylation induced by IAV infection. We found that PIAS1 inhibited the activity of the viral RNP complex, whereas the C351S or W372A mutant of PIAS1, which lacks the SUMO E3 ligase activity, lost the ability to suppress the activity of the viral RNP complex. Notably, the SUMO E3 ligase activity of PIAS1 catalyzed robust SUMOylation of PB2, but had no role in PB1 SUMOylation and a minimal role in NP SUMOylation. Moreover, PIAS1-mediated SUMOylation remarkably reduced the stability of IAV PB2. When tested in vivo, we found that the downregulation of Pias1 expression in mice enhanced the growth and virulence of IAV. Together, our findings define PIAS1 as a restriction factor for the replication and pathogenesis of IAV.
Assuntos
Vírus da Influenza A , Proteínas Inibidoras de STAT Ativados , Sumoilação , Replicação Viral , Animais , Vírus da Influenza A/patogenicidade , Vírus da Influenza A/fisiologia , Camundongos , Proteínas Inibidoras de STAT Ativados/genética , Proteínas Inibidoras de STAT Ativados/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , VirulênciaRESUMO
Highly pathogenic avian influenza (HPAI) subtype H5N1 clade 2.3.4.4b virus has spread globally, causing unprecedented large-scale avian influenza outbreaks since 2020. In 2021, we isolated 17 highly pathogenic avian influenza H5N1 viruses from wild birds in China. To determine virus origin, we genetically analyzed 1,529 clade 2.3.4.4b H5N1 viruses reported globally since October 2020 and found that they formed 35 genotypes. The 17 viruses belonged to genotypes G07, which originated from eastern Asia, and G10, which originated from Russia. The viruses were moderately pathogenic in mice but were highly lethal in ducks. The viruses were in the same antigenic cluster as the current vaccine strain (H5-Re14) used in China. In chickens, the H5/H7 trivalent vaccine provided complete protection against clade 2.3.4.4b H5N1 virus challenge. Our data indicate that vaccination is an effective strategy for preventing and controlling the globally prevalent clade 2.3.4.4b H5N1 virus.
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Virus da Influenza A Subtipo H5N1 , Vírus da Influenza A , Influenza Aviária , Animais , Camundongos , Virus da Influenza A Subtipo H5N1/genética , Galinhas , Animais Selvagens , Vírus da Influenza A/genética , China/epidemiologia , FilogeniaRESUMO
The H7N9 avian influenza virus (AIV) that emerged in China have caused five waves of human infection. Further human cases have been successfully prevented since September 2017 through the use of an H7N9 vaccine in poultry. However, the H7N9 AIV has not been eradicated from poultry in China, and its evolution remains largely unexplored. In this study, we isolated 19 H7N9 AIVs during surveillance and diagnosis from February 2018 to December 2019, and genetic analysis showed that these viruses have formed two different genotypes. Animal studies indicated that the H7N9 viruses are highly lethal to chicken, cause mild infection in ducks, but have distinct pathotypes in mice. The viruses bound to avian-type receptors with high affinity, but gradually lost their ability to bind to human-type receptors. Importantly, we found that H7N9 AIVs isolated in 2019 were antigenically different from the H7N9 vaccine strain that was used for H7N9 influenza control in poultry, and that replication of these viruses cannot, therefore, be completely prevented in vaccinated chickens. We further revealed that two amino acid mutations at positions 135 and 160 in the HA protein added two glycosylation sites and facilitated the escape of the H7N9 viruses from the vaccine-induced immunity. Our study provides important insights into H7N9 virus evolution and control.
Assuntos
Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Vacinas contra Influenza/uso terapêutico , Influenza Aviária/prevenção & controle , Doenças das Aves Domésticas/virologia , Animais , Animais de Zoológico/virologia , Galinhas/virologia , China/epidemiologia , Patos/virologia , Controle de Infecções/métodos , Subtipo H7N9 do Vírus da Influenza A/classificação , Subtipo H7N9 do Vírus da Influenza A/fisiologia , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Camundongos , Filogenia , Vigilância da População , Aves Domésticas , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/prevenção & controleRESUMO
Posttranslational modifications, such as SUMOylation, play specific roles in the life cycle of invading pathogens. However, the effect of SUMOylation on the adaptation, pathogenesis, and transmission of influenza A virus (IAV) remains largely unknown. Here, we found that a conserved lysine residue at position 612 (K612) of the polymerase basic protein 1 (PB1) of IAV is a bona fide SUMOylation site. SUMOylation of PB1 at K612 had no effect on the stability or cellular localization of PB1, but was critical for viral ribonucleoprotein (vRNP) complex activity and virus replication in vitro. When tested in vivo, we found that the virulence of SUMOylation-defective PB1/K612R mutant IAVs was highly attenuated in mice. Moreover, the airborne transmission of a 2009 pandemic H1N1 PB1/K612R mutant virus was impaired in ferrets, resulting in reversion to wild-type PB1 K612. Mechanistically, SUMOylation at K612 was essential for PB1 to act as the enzymatic core of the viral polymerase by preserving its ability to bind viral RNA. Our study reveals an essential role for PB1 K612 SUMOylation in the pathogenesis and transmission of IAVs, which can be targeted for the design of anti-influenza therapies.
Assuntos
Vírus da Influenza A/patogenicidade , Infecções por Orthomyxoviridae/patologia , Infecções por Orthomyxoviridae/transmissão , RNA Viral/metabolismo , Sumoilação , Proteínas Virais/metabolismo , Replicação Viral , Animais , Cães , Feminino , Furões , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Orthomyxoviridae/virologia , RNA Viral/genética , Proteínas Virais/química , Proteínas Virais/genética , Ligação ViralRESUMO
BackgroundTwo human cases of avian influenza A (H3N8) virus infection were reported in China in 2022.AimTo characterise H3N8 viruses circulating in China in September 2021-May 2022.MethodsWe sampled poultry and poultry-related environments in 25 Chinese provinces. After isolating H3N8 viruses, whole genome sequences were obtained for molecular and phylogenetic analyses. The specificity of H3N8 viruses towards human or avian receptors was assessed in vitro. Their ability to replicate in chicken and mice, and to transmit between guinea pigs was also investigated.ResultsIn total, 98 H3N8 avian influenza virus isolates were retrieved from 38,639 samples; genetic analysis of 31 representative isolates revealed 17 genotypes. Viruses belonging to 10 of these genotypes had six internal genes originating from influenza A (H9N2) viruses. These reassorted viruses could be found in live poultry markets and comprised the strains responsible for the two human infections. A subset of nine H3N8 viruses (including six reassorted) that replicated efficiently in mice bound to both avian-type and human-type receptors in vitro. Three reassorted viruses were shed by chickens for up to 9 days, replicating efficiently in their upper respiratory tract. Five reassorted viruses tested on guinea pigs were transmissible among these by respiratory droplets.ConclusionAvian H3N8 viruses with H9N2 virus internal genes, causing two human infections, occurred in live poultry markets in China. The low pathogenicity of H3N8 viruses in poultry allows their continuous circulation with potential for reassortment. Careful monitoring of spill-over infections in humans is important to strengthen early-warning systems and maintain influenza pandemic preparedness.
Assuntos
Vírus da Influenza A Subtipo H3N8 , Vírus da Influenza A Subtipo H9N2 , Influenza Aviária , Influenza Humana , Doenças das Aves Domésticas , Animais , Humanos , Camundongos , Cobaias , Influenza Humana/epidemiologia , Aves Domésticas , Influenza Aviária/epidemiologia , Vírus da Influenza A Subtipo H9N2/genética , Filogenia , Galinhas , China/epidemiologia , Doenças das Aves Domésticas/epidemiologiaRESUMO
[This corrects the article DOI: 10.1371/journal.ppat.1004508.].
RESUMO
Influenza A virus (IAV) coopts numerous host factors to complete its replication cycle. Here, we identify free fatty acid receptor 2 (FFAR2) as a cofactor for IAV entry into host cells. We found that downregulation of FFAR2 or Ffar2 expression significantly reduced the replication of IAV in A549 or RAW 264.7 cells. The treatment of A549 cells with small interfering RNA (siRNA) targeting FFAR2 or the FFAR2 pathway agonists 2-(4-chlorophenyl)-3-methyl-N-(thiazol-2-yl)butanamide (4-CMTB) and compound 58 (Cmp58) [(S)-2-(4-chlorophenyl)-3,3-dimethyl-N-(5-phenylthiazol-2-yl)butanamide] dramatically inhibited the nuclear accumulation of viral nucleoprotein (NP) at early time points postinfection, indicating that FFAR2 functions in the early stage of the IAV replication cycle. FFAR2 downregulation had no effect on the expression of sialic acid (SA) receptors on the cell membrane, the attachment of IAV to the SA receptors, or the activity of the viral ribonucleoprotein (vRNP) complex. Rather, the amount of internalized IAVs was significantly reduced in FFAR2-knocked-down or 4-CMTB- or Cmp58-treated A549 cells. Further studies showed that FFAR2 associated with ß-arrestin1 and that ß-arrestin1 interacted with the ß2-subunit of the AP-2 complex (AP2B1), the essential adaptor of the clathrin-mediated endocytosis pathway. Notably, siRNA knockdown of either ß-arrestin1 or AP2B1 dramatically impaired IAV replication, and AP2B1 knockdown or treatment with Barbadin, an inhibitor targeting the ß-arrestin1/AP2B1 complex, remarkably decreased the amount of internalized IAVs. Moreover, we found that FFAR2 interacted with three G protein-coupled receptor (GPCR) kinases (i.e., GRK2, GRK5, and GRK6) whose downregulation inhibited IAV replication. Together, our findings demonstrate that the FFAR2 signaling cascade is important for the efficient endocytosis of IAV into host cells.IMPORTANCE To complete its replication cycle, IAV hijacks the host endocytosis machinery to invade cells. However, the underlying mechanisms of how IAV is internalized into host cells remain poorly understood, emphasizing the need to elucidate the role of host factors in IAV entry into cells. In this study, we identified FFAR2 as an important host factor for the efficient replication of both low-pathogenic and highly pathogenic IAV. We revealed that FFAR2 facilitates the internalization of IAV into target cells during the early stage of infection. Upon further characterization of the role of FFAR2-associated proteins in virus replication, we found that the FFAR2-ß-arrestin1-AP2B1 signaling cascade is important for the efficient endocytosis of IAV. Our findings thus further our understanding of the biological details of IAV entry into host cells and establish FFAR2 as a potential target for antiviral drug development.
Assuntos
Endocitose , Vírus da Influenza A/fisiologia , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais , Internalização do Vírus , Células A549 , Subunidades beta do Complexo de Proteínas Adaptadoras/genética , Subunidades beta do Complexo de Proteínas Adaptadoras/metabolismo , Animais , Cães , Células HEK293 , Humanos , Células Madin Darby de Rim Canino , Camundongos , Células RAW 264.7 , Receptores Acoplados a Proteínas G/genética , Replicação Viral/fisiologia , beta-Arrestina 1/genética , beta-Arrestina 1/metabolismoRESUMO
The H5N1 avian influenza viruses emerged in Southeast Asia in the late 20th century and have evolved into multiple phylogenetic clades based on their hemagglutinin (HA)-encoding genes. The clade 7.2 viruses were first detected in chickens in northern China in 2006, and vaccines specifically targeted to the clade were developed and have been used in poultry in China since 2006. During routine surveillance and disease diagnosis, we isolated seven H5 viruses between 2011 and 2014 that bear the clade 7.2 HA genes. Here, we performed extensive studies to understand how the clade 7.2 H5 viruses have evolved in chickens in China. Full genome sequence analysis revealed that the seven viruses formed two subtypes (four H5N1 viruses and three H5N2 viruses) and four genotypes by deriving genes from other influenza viruses. All of the viruses had antigenically drifted from the clade 7.2 viruses that were isolated in 2006. Pathogenicity studies of four viruses, one from each genotype, revealed that all of the viruses are highly pathogenic in chickens, but none of them could replicate in ducks. The four viruses exclusively bound to avian-type receptors and replicated only in the turbinates and/or lungs of mice; none of them were lethal to mice at a dosage of 106 50% egg infective doses (EID50). Our study indicates that although the clade 7.2 viruses have not been eradicated from poultry through vaccination, they have not become more dangerous to other animals (e.g., ducks and mice) and humans. IMPORTANCE: Animal influenza viruses can acquire the ability to infect and kill humans. The H5N1 viruses have been a concern in recent decades because of their clear pandemic potential. We sorted H5N1 influenza viruses into different phylogenetic clades based on their HA genes. The clade 7.2 viruses were detected in chickens in several provinces of northern China in 2006. Vaccines for these viruses were subsequently developed and have been used ever since to control infection of poultry. Here, we analyzed the genetic and biologic properties of seven clade 7.2 viruses that were isolated from chickens between 2011 and 2014. We found that after nearly 9 years of circulation in chickens, the clade 7.2 viruses still exclusively bind to avian-type receptors and are of low pathogenicity to mice, suggesting that these H5 viruses pose a low risk to human public health.
Assuntos
Virus da Influenza A Subtipo H5N1/genética , Vírus da Influenza A Subtipo H5N2/genética , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Animais , Galinhas , China/epidemiologia , Patos/virologia , Genoma Viral/genética , Genótipo , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Virus da Influenza A Subtipo H5N1/imunologia , Vírus da Influenza A Subtipo H5N2/imunologia , Vacinas contra Influenza/imunologia , Influenza Aviária/imunologia , Filogenia , Aves Domésticas , Vacinação/métodosRESUMO
UNLABELLED: H4 avian influenza virus (AIV) is one of the most prevalent influenza virus subtypes in the world. However, whether H4 AIVs pose a threat to public health remains largely unclear. Here, we analyzed the phylogenetic relationships, receptor binding properties, replication, and transmissibility in mammals of H4 AIVs isolated from live poultry markets in China between 2009 and 2012. Genomic sequence analysis of 36 representative H4 viruses revealed 32 different genotypes, indicating that these viruses are undergoing complex and frequent reassortment events. All 32 viruses tested could replicate in the respiratory organs of infected mice without prior adaptation. Receptor binding analysis demonstrated that the H4 AIVs bound to α-2,6-linked glycans, although they retained the binding preference for α-2,3-linked glycans. When we tested the direct-contact transmission of 10 H4 viruses in guinea pigs, we found that three viruses did not transmit to any of the contact animals, one virus transmitted to one of three contact animals, and six viruses transmitted to all three contact animals. When we further tested the respiratory droplet transmissibility of four of the viruses that transmitted efficiently via direct contact, we found that three of them could transmit to one or two of the five exposed animals. Our study demonstrates that the current circulating H4 AIVs can infect, replicate in, and transmit to mammalian hosts, thereby posing a potential threat to human health. These findings emphasize the continual need for enhanced surveillance of H4 AIVs. IMPORTANCE: Numerous surveillance studies have documented the wide distribution of H4 AIVs throughout the world, yet the biological properties of H4 viruses have not been well studied. In this study, we found that multiple genotypes of H4 viruses are cocirculating in the live poultry markets of China and that H4 viruses can replicate in mice, possess human-type receptor binding specificity, and transmit between guinea pigs via direct contact. Strikingly, some H4 strains also can transmit via respiratory droplet, albeit with limited efficiency. These results clearly show the potential threat posed by H4 viruses to public health.
Assuntos
Vírus da Influenza A/crescimento & desenvolvimento , Vírus da Influenza A/isolamento & purificação , Influenza Aviária/virologia , Infecções por Orthomyxoviridae/veterinária , Aves Domésticas/virologia , Ligação Viral , Replicação Viral , Animais , China , Análise por Conglomerados , Feminino , Genoma Viral , Cobaias , Vírus da Influenza A/genética , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Infecções por Orthomyxoviridae/transmissão , Filogenia , RNA Viral/genética , Receptores Virais/análise , Análise de Sequência de DNA , Homologia de SequênciaRESUMO
BACKGROUND: Non-structural protein 1 (NS1) is a multifunctional protein and a crucial regulatory factor in the replication and pathogenesis of avian influenza virus (AIV). Studies have shown that NS1 can interact with a variety of host proteins to modulate the viral life cycle. We previously generated a monoclonal antibody against NS1 protein; In the current research study, using this antibody, we immunoprecipitated host proteins that interact with NS1 to better understand the roles played by NS1 in communications between virus and host. RESULTS: Co-immunoprecipitation experiments identified annexin A2 (ANXA2) as a target molecule interacting with NS1. Results from confocal laser scanning microscopy indicated that NS1 co-localized with ANXA2 in the cell cytoplasm. Overexpression of ANXA2 significantly increased the titer of H5N1 subtype HPAIV, whereas siRNA-mediated knockdown of ANXA2 markedly inhibited the expression of viral proteins and reduced the progeny virus titer. CONCLUSIONS: Our results indicate that ANXA2 interacts with NS1 and ANXA2 expression increases HPAIV replication.
Assuntos
Anexina A2/metabolismo , Anexina A2/farmacologia , Virus da Influenza A Subtipo H5N1/fisiologia , Proteínas não Estruturais Virais/metabolismo , Replicação Viral/fisiologia , Células A549 , Animais , Anexina A2/genética , Citoplasma/metabolismo , Citoplasma/virologia , Técnicas de Silenciamento de Genes , Células HEK293 , Interações Hospedeiro-Patógeno , Humanos , Imunoprecipitação/métodos , Estágios do Ciclo de Vida , Microscopia Confocal , Domínios e Motivos de Interação entre Proteínas , Interferência de RNA , Proteínas Virais/metabolismoRESUMO
H9N2 subtype influenza viruses have been detected in different species of wild birds and domestic poultry in many countries for several decades. Because these viruses are of low pathogenicity in poultry, their eradication is not a priority for animal disease control in many countries, which has allowed them to continue to evolve and spread. Here, we characterized the genetic variation, receptor-binding specificity, replication capability, and transmission in mammals of a series of H9N2 influenza viruses that were detected in live poultry markets in southern China between 2009 and 2013. Thirty-five viruses represented 17 genotypes on the basis of genomic diversity, and one specific "internal-gene-combination" predominated among the H9N2 viruses. This gene combination was also present in the H7N9 and H10N8 viruses that have infected humans in China. All of the 35 viruses preferentially bound to the human-like receptor, although two also retained the ability to bind to the avian-like receptor. Six of nine viruses tested were transmissible in ferrets by respiratory droplet; two were highly transmissible. Some H9N2 viruses readily acquired the 627K or 701N mutation in their PB2 gene upon infection of ferrets, further enhancing their virulence and transmission in mammals. Our study indicates that the widespread dissemination of H9N2 viruses poses a threat to human health not only because of the potential of these viruses to cause an influenza pandemic, but also because they can function as "vehicles" to deliver different subtypes of influenza viruses from avian species to humans.
Assuntos
Variação Genética , Vírus da Influenza A Subtipo H9N2 , Influenza Aviária , Influenza Humana , Animais , Sequência de Bases , Galinhas , China , Cães , Furões , Humanos , Vírus da Influenza A Subtipo H9N2/genética , Vírus da Influenza A Subtipo H9N2/isolamento & purificação , Vírus da Influenza A Subtipo H9N2/patogenicidade , Influenza Aviária/genética , Influenza Aviária/transmissão , Influenza Humana/genética , Influenza Humana/transmissão , Células Madin Darby de Rim Canino , Dados de Sequência Molecular , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/transmissão , Doenças das Aves Domésticas/virologiaRESUMO
In February 2014, while investigating the source of a human infection with influenza A(H7N9) virus in northern China, we isolated subtypes H7N2 and H9N2 viruses from chickens on the patient's farm. Sequence analysis revealed that the H7N2 virus is a novel reassortant of H7N9 and H9N2 viruses. Continued surveillance is needed.
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Galinhas , Vírus da Influenza A Subtipo H7N2/isolamento & purificação , Influenza Aviária/virologia , Animais , Anticorpos Antivirais , Protocolos de Quimioterapia Combinada Antineoplásica , Bioensaio , China/epidemiologia , Cisplatino , Feminino , Humanos , Ifosfamida , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Influenza Aviária/epidemiologia , Masculino , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Mitomicina , Infecções por Orthomyxoviridae/virologia , Replicação ViralRESUMO
To gain insight into the ecology of avian influenza viruses (AIV), we conducted active influenza virus surveillance in domestic ducks on farms located on the flyway of migratory birds in the Dongting Lake region of Hunan Province, China, from winter 2011 until spring 2012. Specimens comprising 3,030 duck swab samples and 1,010 environmental samples were collected from 101 duck farms. We isolated AIV of various HA subtypes, including H3, H4, H5, H6, H9, H10, H11, and H12. We sequenced the entire coding sequences of the genomes of 28 representative isolates constituting 13 specific subtypes. When the phylogenetic relationships among these isolates were examined, we observed that extensive reassortment events had occurred. Among the 28 Dongting Lake viruses, 21 genotypes involving the six internal genes were identified. Furthermore, we identified viruses or viral genes introduced from other countries, viral gene segments of unknown origin, and a novel HA/NA combination. Our findings emphasize the importance of farmed domestic ducks in the Dongting Lake region to the genesis and evolution of AIV and highlight the need for continued surveillance of domestic ducks in this region.
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Patos/virologia , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Influenza Aviária/virologia , Vírus Reordenados/classificação , Vírus Reordenados/genética , Criação de Animais Domésticos , Animais , Animais Domésticos/virologia , China , Ecossistema , Genes Virais , Genoma Viral , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Vírus da Influenza A/isolamento & purificação , Filogenia , Vírus Reordenados/isolamento & purificaçãoRESUMO
Due to the fact that many avian influenza viruses that kill chickens are not lethal to ducks, farmers are reluctant to use avian influenza inactivated vaccines on ducks. Large numbers of unvaccinated ducks play an important role in the transmission of avian influenza viruses from wild birds to domestic poultry, creating a substantial challenge to vaccination strategies for avian influenza control. To solve this problem, we constructed a recombinant duck enteritis virus (DEV), rDEV-dH5/H7, using a live attenuated DEV vaccine strain (vDEV) as a vector. rDEV-dH5/H7 carries the hemagglutinin gene of two H5 viruses [GZ/S4184/17 (H5N6) (clade 2.3.4.4â h) and LN/SD007/17 (H5N1) (clade 2.3.2.1d)] and an H7 virus [GX/SD098/17 (H7N9)]. These three hemagglutinin genes were stably inherited in rDEV-dH5/H7 and expressed in rDEV-dH5/H7-infected cells. Animal studies revealed that rDEV-dH5/H7 and vDEV induced similar neutralizing antibody responses and protection against lethal DEV challenge. Importantly, rDEV-dH5/H7 induced strong and long-lasting hemagglutinin inhibition antibodies against different H5 and H7 viruses and provided complete protection against challenges with homologous and heterologous highly pathogenic H5 and H7 influenza viruses in ducks. Our study shows that rDEV-dH5/H7 could serve as an ideal live attenuated vaccine to protect ducks against infection with lethal DEV and highly pathogenic avian influenza viruses.
Assuntos
Enterite , Virus da Influenza A Subtipo H5N1 , Subtipo H7N9 do Vírus da Influenza A , Vacinas contra Influenza , Influenza Aviária , Animais , Patos , Hemaglutininas , Galinhas , Virus da Influenza A Subtipo H5N1/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Subtipo H7N9 do Vírus da Influenza A/genética , Vacinas contra Influenza/genética , Vetores GenéticosRESUMO
Avian influenza viruses (AIVs) of the H5 subtype rank among the most serious pathogens, leading to significant economic losses in the global poultry industry and posing risks to human health. Therefore, rapid and accurate virus detection is crucial for the prevention and control of H5 AIVs. In this study, we established a novel detection method for H5 viruses by utilizing the precision of CRISPR/Cas12a and the efficiency of RT-RPA technologies. This assay facilitates the direct visualization of detection results through blue light and lateral flow strips, accurately identifying H5 viruses with high specificity and without cross-reactivity against other AIV subtypes, NDV, IBV, and IBDV. With detection thresholds of 1.9 copies/µL (blue light) and 1.9 × 103 copies/µL (lateral flow strips), our method not only competes with but also slightly surpasses RT-qPCR, demonstrating an 80.70% positive detection rate across 81 clinical samples. The RT-RPA/CRISPR-based detection method is characterized by high sensitivity, specificity, and independence from specialized equipment. The immediate field applicability of the RT-RPA/CRISPR approach underscores its importance as an effective tool for the early detection and management of outbreaks caused by the H5 subtype of AIVs.
Assuntos
Sistemas CRISPR-Cas , Influenza Aviária , Sensibilidade e Especificidade , Animais , Influenza Aviária/virologia , Influenza Aviária/diagnóstico , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Virus da Influenza A Subtipo H5N1/classificação , Vírus da Influenza A/genética , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/classificação , Aves Domésticas/virologia , Doenças das Aves Domésticas/virologia , Doenças das Aves Domésticas/diagnóstico , Galinhas/virologia , Aves/virologiaRESUMO
H5N1 avian influenza viruses bearing the clade 2.3.2.1 hemagglutinin (HA) gene have been widely detected in birds and poultry in several countries. During our routine surveillance, we isolated 28 H5N1 viruses between January 2017 and October 2020. To investigate the genetic relationship of the globally circulating H5N1 viruses and the biological properties of those detected in China, we performed a detailed phylogenic analysis of 274 representative H5N1 strains and analyzed the antigenic properties, receptor-binding preference, and virulence in mice of the H5N1 viruses isolated in China. The phylogenic analysis indicated that the HA genes of the 274 viruses belonged to six subclades, namely clades 2.3.2.1a to 2.3.2.1f; these viruses acquired gene mutations and underwent complicated reassortment to form 58 genotypes, with G43 being the dominant genotype detected in eight Asian and African countries. The 28 H5N1 viruses detected in this study carried the HA of clade 2.3.2.1c (two strains), 2.3.2.1d (three strains), or 2.3.2.1f (23 strains), and formed eight genotypes. These viruses were antigenically well-matched with the H5-Re12 vaccine strain used in China. Animal studies showed that the pathogenicity of the H5N1 viruses ranged from non-lethal to highly lethal in mice. Moreover, the viruses exclusively bound to avian-type receptors and have not acquired the ability to bind to human-type receptors. Our study reveals the overall picture of the evolution of clade 2.3.2.1 H5N1 viruses and provides insights into the control of these viruses.
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Virus da Influenza A Subtipo H5N1 , Influenza Aviária , Animais , Humanos , Camundongos , Hemaglutininas/genética , Aves , Aves Domésticas , Filogenia , Galinhas , Glicoproteínas de Hemaglutininação de Vírus da Influenza/químicaRESUMO
Influenza A virus (IAV) commandeers numerous host cellular factors for successful replication. However, very few host factors have been revealed to be involved in the fusion of viral envelope and late endosomal membranes. In this study, we identified cation-dependent mannose-6-phosphate receptor (M6PR) as a crucial host factor for the replication of IAV. We found that siRNA knockdown of M6PR expression significantly reduced the growth titers of different subtypes of IAV, and that the inhibitory effect of M6PR siRNA treatment on IAV growth was overcome by the complement of exogenously expressed M6PR. When A549 cells were treated with siRNA targeting M6PR, the nuclear accumulation of viral nucleoprotein (NP) was dramatically inhibited at early timepoints post-infection, indicating that M6PR engages in the early stage of the IAV replication cycle. By investigating the role of M6PR in the individual entry and post-entry steps of IAV replication, we found that the downregulation of M6PR expression had no effect on attachment, internalization, early endosome trafficking, or late endosome acidification. However, we found that M6PR expression was critical for the fusion of viral envelope and late endosomal membranes. Of note, M6PR interacted with the hemagglutinin (HA) protein of IAV, and further studies showed that the lumenal domain of M6PR and the ectodomain of HA2 mediated the interaction and directly promoted the fusion of the viral and late endosomal membranes, thereby facilitating IAV replication. Together, our findings highlight the importance of the M6PR-HA interaction in the fusion of viral and late endosomal membranes during IAV replication.
Assuntos
Vírus da Influenza A , Influenza Humana , Humanos , Vírus da Influenza A/genética , Endossomos/metabolismo , Membranas Intracelulares , Células A549 , RNA Interferente Pequeno/metabolismo , Replicação Viral , Influenza Humana/genéticaRESUMO
Influenza virus infection is initiated by the attachment of the viral haemagglutinin (HA) protein to sialic acid receptors on the host cell surface. Most virus particles enter cells through clathrin-mediated endocytosis (CME). However, it is unclear how viral binding signals are transmitted through the plasma membrane triggering CME. Here we found that metabotropic glutamate receptor subtype 2 (mGluR2) and potassium calcium-activated channel subfamily M alpha 1 (KCa1.1) are involved in the initiation and completion of CME of influenza virus using an siRNA screen approach. Influenza virus HA directly interacted with mGluR2 and used it as an endocytic receptor to initiate CME. mGluR2 interacted and activated KCa1.1, leading to polymerization of F-actin, maturation of clathrin-coated pits and completion of the CME of influenza virus. Importantly, mGluR2-knockout mice were significantly more resistant to different influenza subtypes than the wild type. Therefore, blocking HA and mGluR2 interaction could be a promising host-directed antiviral strategy.
Assuntos
Endocitose , Camundongos Knockout , Receptores de Glutamato Metabotrópico , Animais , Receptores de Glutamato Metabotrópico/metabolismo , Receptores de Glutamato Metabotrópico/genética , Camundongos , Humanos , Internalização do Vírus , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Clatrina/metabolismo , Infecções por Orthomyxoviridae/virologia , Infecções por Orthomyxoviridae/metabolismo , Células HEK293 , Actinas/metabolismo , Cães , Células Madin Darby de Rim Canino , Receptores Virais/metabolismo , Receptores Virais/genética , Influenza Humana/virologia , Influenza Humana/metabolismo , Orthomyxoviridae/fisiologia , Orthomyxoviridae/genética , Orthomyxoviridae/metabolismoRESUMO
The global spread of H5 clade 2.3.4.4 highly pathogenic avian influenza (HPAI) viruses threatens poultry and public health. The continuous circulation of these viruses has led to their considerable genetic and antigenic evolution, resulting in the formation of eight subclades (2.3.4.4a-h). Here, we examined the antigenic sites that determine the antigenic differences between two H5 vaccine strains, H5-Re8 (clade 2.3.4.4g) and H5-Re11 (clade 2.3.4.4h). Epitope mapping data revealed that all eight identified antigenic sites were located within two classical antigenic regions, with five sites in region A (positions 115, 120, 124, 126, and 140) and three in region B (positions 151, 156, and 185). Through antigenic cartography analysis of mutants with varying numbers of substitutions, we confirmed that a combination of mutations in these eight sites reverses the antigenicity of H5-Re11 to that of H5-Re8, and vice versa. More importantly, our analyses identified H5-Re11_Q115L/R120S/A156T (H5-Re11 + 3) as a promising candidate for a broad-spectrum vaccine, positioned centrally in the antigenic map, and offering potential universal protection against all variants within the clade 2.3.4.4. H5-Re11 + 3 serum has better cross-reactivity than sera generated with other 2.3.4.4 vaccines, and H5-Re11 + 3 vaccine provided 100% protection of chickens against antigenically drifted H5 viruses from various 2.3.4.4 antigenic groups. Our findings suggest that antigenic regions A and B are immunodominant in H5 viruses, and that antigenic cartography-guided vaccine design is a promising strategy for selecting a broad-spectrum vaccine.
RESUMO
Human infections with the H7N9 influenza virus have been eliminated in China through vaccination of poultry; however, the H7N9 virus has not yet been eradicated from poultry. Carefully analysis of H7N9 viruses in poultry that have sub-optimal immunity may provide a unique opportunity to witness the evolution of highly pathogenic avian influenza virus in the context of vaccination. Between January 2020 and June 2023, we isolated 16 H7N9 viruses from samples we collected during surveillance and samples that were sent to us for disease diagnosis. Genetic analysis indicated that these viruses belonged to a single genotype previously detected in poultry. Antigenic analysis indicated that 12 of the 16 viruses were antigenically close to the H7-Re4 vaccine virus that has been used since January 2022, and the other four viruses showed reduced reactivity with the vaccine. Animal studies indicated that all 16 viruses were nonlethal in mice, and four of six viruses showed reduced virulence in chickens upon intranasally inoculation. Importantly, the H7N9 viruses detected in this study exclusively bound to the avian-type receptors, having lost the capacity to bind to human-type receptors. Our study shows that vaccination slows the evolution of H7N9 virus by preventing its reassortment with other viruses and eliminates a harmful characteristic of H7N9 virus, namely its ability to bind to human-type receptors.