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African swine fever (ASF) is a devastating disease caused by the African swine fever virus (ASFV) that adversely affects the pig industry. The spleen is the main target organ of ASFV; however, the function of metabolites in the spleen during ASFV infection is yet to be investigated. To define the metabolic changes in the spleen after ASFV infection, untargeted and targeted metabolomics analyses of spleens from ASFV-infected pigs were conducted. Untargeted metabolomics analysis revealed 540 metabolites with significant differential levels. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that these metabolites were mainly enriched in metabolic pathways, including nucleotide metabolism, purine metabolism, arginine biosynthesis, and neuroactive ligand-receptor interaction. Moreover, 134 of 540 metabolites quantified by targeted metabolomics analysis had differential levels and were enriched in metabolic pathways such as the biosynthesis of cofactors, ABC transporters, and biosynthesis of amino acids. Furthermore, coalition analysis of untargeted and targeted metabolomics data revealed that the levels of acylcarnitines, which are intermediates of fatty acid ß-oxidation, were significantly increased in ASFV-infected spleens compared with those in the uninfected spleens. Moreover, inhibiting fatty acid ß-oxidation significantly reduced ASFV replication, indicating that fatty acid ß-oxidation is essential for this process. To our knowledge, this is the first report presenting the metabolite profiles of ASFV-infected pigs. This study revealed a new mechanism of ASFV-mediated regulation of host metabolism. These findings provide new insights into the pathogenic mechanisms of ASFV, which will benefit the development of target drugs for ASFV replication. IMPORTANCE African swine fever virus, the only member of the Asfarviridae family, relies on hijacking host metabolism to meet the demand for self-replication. However, the change in host metabolism after African swine fever virus (ASFV) infection remains unknown. Here, we analyzed the metabolic changes in the pig spleen after ASFV infection for the first time. ASFV infection increased the levels of acylcarnitines. Inhibition of the production and metabolism of acylcarnitines inhibited ASFV replication. Acylcarnitines are the vital intermediates of fatty acid ß-oxidation. This study highlights the critical role of fatty acid ß-oxidation in ASFV infection, which may help identify target drugs to control African swine fever disease.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Carnitina , Bazo , Replicación Viral , Animales , Virus de la Fiebre Porcina Africana/fisiología , Ácidos Grasos/metabolismo , Metabolómica , Bazo/metabolismo , Porcinos , Carnitina/análisisRESUMEN
African swine fever (ASF) is an infectious disease caused by the African swine fever virus (ASFV), and has a high mortality rate. It has caused serious socioeconomic consequences worldwide. Currently, there are no available commercial vaccines or antiviral drug interventions. D1133L is one of the key genes for ASFV replication and antiviral drug screening. In this study, a virtual screening software program, PyRx, was used to screen libraries of compounds against the potential drug target D1133L. Twelve compounds with a high affinity for ASFV D1133L were screened, and cyproheptadine hydrochloride (periactin) was identified as a candidate drug. The periactin has little cytotoxicity, and which dose-dependently inhibited ASFV replication in vitro. Further research indicated that periactin could significantly down-regulate D1133L at the transcriptional and protein levels with RT-qPCR and western blot methods. This study has provided important candidate drugs for the prevention and treatment of ASF, as well as biological materials and new fields of view for the research and development of vaccines and drugs for ASFV.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Vacunas , Porcinos , Animales , Virus de la Fiebre Porcina Africana/genética , Fiebre Porcina Africana/tratamiento farmacológico , Fiebre Porcina Africana/prevención & control , Replicación Viral , Antivirales/farmacología , Antivirales/metabolismo , Ciproheptadina/metabolismo , Ciproheptadina/farmacologíaRESUMEN
African swine fever (ASF) is a severe infectious disease caused by the African swine fever virus (ASFV), seriously endangering the global pig industry. ASFV possesses a large genome, strong mutation ability, and complex immune escape mechanisms. Since the first case of ASF was reported in China in August 2018, it has had a significant impact on social economy and food safety. In the present study, pregnant swine serum (PSS) was found to promote viral replication; differentially expressed proteins (DEPs) in PSS were screened and identified using the isobaric tags for relative and absolute quantitation technology and compared with those in non-pregnant swine serum (NPSS). The DEPs were analyzed using Gene Ontology functional annotation, Kyoto Protocol Encyclopedia of Genes and Genome pathway enrichment, and protein-protein interaction networks. In addition, the DEPs were validated via western blot and RT-qPCR experiments. And the 342 of DEPs were identified in bone marrow-derived macrophages cultured with PSS compared with the NPSS. The 256 were upregulated and 86 of DEPs were downregulated. The primary biological functions of these DEPs involved signaling pathways that regulate cellular immune responses, growth cycles, and metabolism-related pathways. An overexpression experiment showed that the PCNA could promote ASFV replication whereas MASP1 and BST2 could inhibit it. These results further indicated that some protein molecules in PSS were involved in the regulation of ASFV replication. In the present study, the role of PSS in ASFV replication was analyzed using proteomics, and the study will be provided a basis for future detailed research on the pathogenic mechanism and host interactions of ASFV as well as new insights for the development of small-molecule compounds to inhibit ASFV.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Porcinos , Animales , Virus de la Fiebre Porcina Africana/genética , Proteómica , Replicación Viral , MutaciónRESUMEN
DEAD-box decapping enzyme 20 (DDX20) is a putative RNA-decapping enzyme that can be identified by the conserved motif Asp-Glu-Ala-Asp (DEAD). Cellular processes involve numerous RNA secondary structure alterations, including translation initiation, nuclear and mitochondrial splicing, and assembly of ribosomes and spliceosomes. DDX20 reportedly plays an important role in cellular transcription and post-transcriptional modifications. On the one hand, DDX20 can interact with various transcription factors and repress the transcriptional process. On the other hand, DDX20 forms the survival motor neuron complex and participates in the assembly of snRNP, ultimately affecting the RNA splicing process. Finally, DDX20 can potentially rely on its RNA-unwinding enzyme function to participate in microRNA (miRNA) maturation and act as a component of the RNA-induced silencing complex. In addition, although DDX20 is not a key component in the innate immune system signaling pathway, it can affect the nuclear factor kappa B (NF-κB) and p53 signaling pathways. In particular, DDX20 plays different roles in tumorigenesis development through the NF-κB signaling pathway. This process is regulated by various factors such as miRNA. DDX20 can influence processes such as viral replication in cells by interacting with two proteins in Epstein-Barr virus and can regulate the replication process of several viruses through the innate immune system, indicating that DDX20 plays an important role in the innate immune system. Herein, we review the effects of DDX20 on the innate immune system and its role in transcriptional and post-transcriptional modification processes, based on which we provide an outlook on the future of DDX20 research in innate immunity and viral infections.
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Infecciones por Virus de Epstein-Barr , MicroARNs , Humanos , FN-kappa B/metabolismo , Herpesvirus Humano 4 , Factores de Transcripción/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Inmunidad Innata , Proteína 20 DEAD-Box/metabolismoRESUMEN
Z-conformation nucleic acid binding protein 1 (ZBP1), a powerful innate immune sensor, has been identified as the important signaling initiation factor in innate immune response and the multiple inflammatory cell death known as PANoptosis. The initiation of ZBP1 signaling requires recognition of left-handed double-helix Z-nucleic acid (includes Z-DNA and Z-RNA) and subsequent signaling transduction depends on the interaction between ZBP1 and its adapter proteins, such as TANK-binding kinase 1 (TBK1), interferon regulatory factor 3 (IRF3), receptor-interacting serine/threonine-protein kinase 1 (RIPK1), and RIPK3. ZBP1 activated innate immunity, including type-I interferon (IFN-I) response and NF-κB signaling, constitutes an important line of defense against pathogenic infection. In addition, ZBP1-mediated PANoptosis is a double-edged sword in anti-infection, auto-inflammatory diseases, and tumor immunity. ZBP1-mediated PANoptosis is beneficial for eliminating infected cells and tumor cells, but abnormal or excessive PANoptosis can lead to a strong inflammatory response that is harmful to the host. Thus, pathogens and host have each developed multiplex tactics targeting ZBP1 signaling to maintain strong virulence or immune homeostasis. In this paper, we reviewed the mechanisms of ZBP1 signaling, the effects of ZBP1 signaling on host immunity and pathogen infection, and various antagonistic strategies of host and pathogen against ZBP1. We also discuss existent gaps regarding ZBP1 signaling and forecast potential directions for future research.
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ADN de Forma Z , Interferón Tipo I , Ácidos Nucleicos , Inmunidad Innata , Factor 3 Regulador del Interferón/metabolismo , Interferón Tipo I/metabolismo , FN-kappa B/metabolismo , ARN , Proteínas de Unión al ARN/metabolismo , Serina/genética , Treonina/genéticaRESUMEN
BACKGROUND: Peste des petits ruminants (PPR) and goat pox (GTP) are two devastating animal epidemic diseases that affect small ruminants. Vaccination is one of the most important measures to prevent and control these two severe infectious diseases. METHODS: In this study, we vaccinated sheep with PPR and POX vaccines to compare the changes in the antibody levels between animals vaccinated with PPRV and POX vaccines alone and those co-infected with both vaccines simultaneously. The cell infection model was used to explore the interference mechanism between the vaccines in vitro. The antibody levels were detected with the commercial ELISA kit. The Real-time Quantitative PCR fluorescent quantitative PCR method was employed to detect the viral load changes and cytokines expression after the infection. RESULTS: The concurrent immunization of GTP and PPR vaccine enhanced the PPR vaccine's immune effect but inhibited the immune effect of the GTP vaccine. After the infection, GTP and PPR vaccine strains caused cytopathic effect; co-infection with GTP and PPR vaccine strains inhibited the replication of PPR vaccine strains; co-infection with GTP and PPR vaccine strains enhanced the replication of GTP vaccine strains. Moreover, virus mixed infection enhanced the mRNA expressions of TNF-α, IL-1ß, IL-6, IL-10, IFN-α, and IFN-ß by 2-170 times. GTP vaccine strains infection alone can enhanced the mRNA expression of IL-1ß, TNF-α, IL-6, IL-10, while the expression of IFN-α mRNA is inhibited. PPR vaccine strains alone can enhanced the mRNA expression of IFN-α, IFN-ß, TNF-α, and has little effect the mRNA expression of IL-1ß, IL-6 and IL-10. The results showed that GTP and PPR vaccine used simultaneously in sheep enhanced the PPR vaccine's immune effect but inhibited the immune effect of the GTP vaccine in vivo. Furthermore, an infection of GTP and PPR vaccine strains caused significant cell lesions in vitro; co-infection with GTP + PPR vaccine strains inhibited the replication of PPR vaccine strains, while the co-infection of GTP followed by PPR infection enhanced the replication of GTP vaccine strains. Moreover, virus infection enhanced the expressions of TNF-α, IL-1ß, IL-6, IL-10, IFN-α, and IFN-ß. CONCLUSIONS: Peste des petits ruminants and capripox vaccine strains interfere with each other in vivo and vitro.
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Coinfección , Peste de los Pequeños Rumiantes , Infecciones por Poxviridae , Enfermedades de las Ovejas , Vacunas Virales/inmunología , Animales , Anticuerpos Antivirales/sangre , Coinfección/virología , Guanosina Trifosfato , Interleucina-10 , Interleucina-6 , Peste de los Pequeños Rumiantes/diagnóstico , Infecciones por Poxviridae/diagnóstico , Infecciones por Poxviridae/veterinaria , ARN Mensajero , Ovinos , Enfermedades de las Ovejas/virología , Factor de Necrosis Tumoral alfaRESUMEN
BACKGROUND: African swine fever virus (ASFV) is a highly lethal virus that can infect porcine alveolar macrophages (PAMs). Since ASFV, China has dealt with a heavy blow to the pig industry. However, the effect of infection of ASFV strains isolated from China on PAM transcription level is not yet clarified. METHODS: In this study, RNA sequencing (RNA-seq) was used to detect the differential expression of genes in PAMs at different time points after ASFV-CN/GS/2018 infection. The fluorescent quantitative polymerase chain reaction (qPCR) method was used to confirm the altered expression of related genes in PAMs infected with ASFV. RESULTS: A total of 1154 differentially expressed genes were identified after ASFV-CN/GS/2018 infection, of which 816 were upregulated, and 338 were downregulated. GO and KEGG analysis showed that these genes were dynamically enriched in various biological processes, including innate immune response, inflammatory response, chemokines, and apoptosis. Furthermore, qPCR verified that the DEAD box polypeptide 58 (DDX58), Interferon-induced helicase C domain-containing protein 1 (IFIH1), Toll-like receptor 3 (TLR3), and TLR7 of PAMs were upregulated after ASFV infection, while TLR4 and TLR6 had a significant downward trend during ASFV infection. The expression of some factors related to antiviral and inflammation was altered significantly after ASFV infection, among which interferon-induced protein with tetratricopeptide repeats 1 (IFIT1), IFIT2, Interleukin-6 (IL-6) were upregulated, and Ewing's tumor-associated antigen 1 homolog (ETAA1) and Prosaposin receptor GPR37 (GPR37) were downregulated. In addition, we discovered that ASFV infection is involved in the regulation of chemokine expression in PAMs, and the chemokines, such as C-X-C motif chemokine 8 (CXCL8) and CXCL10, were upregulated after infection. However, the expression of chemokine receptor C-X-C chemokine receptor type 2 (CXCR2) is downregulated. Also, that the transcriptional levels of pro-apoptotic and anti-apoptotic factors changed after infection. CONCLUSIONS: After ASFV-CN/GS/2018 infection, the expression of some antiviral and inflammatory factors in PAMs changed significantly. The ASFV infection may activates the RLR and TLR signaling pathways. In addition, ASFV infection is involved in regulating of chemokine expression in PAMs and host cell apoptosis.
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Fiebre Porcina Africana , Expresión Génica , Interacciones Huésped-Patógeno , Macrófagos/virología , Virus de la Fiebre Porcina Africana , Animales , Quimiocinas/inmunología , Inmunidad Innata , Macrófagos/inmunología , Receptores de Quimiocina/inmunología , Porcinos , Receptores Toll-LikeRESUMEN
An amendment to this paper has been published and can be accessed via the original article.
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Seneca Valley virus (SVV) is a non-encapsulated single-stranded positive-strand RNA virus whose transmission routes have not yet been fully elucidated. Exosomes have been implicated in the intercellular transport of a variety of materials, such as proteins, RNA, and liposomes. However, whether exosomes can mediate SVV intercellular transmission remains unknown. In this study, we extracted exosomes from SVV-infected IBRS-2 cells to investigate intercellular transmission. Our results suggest that the intercellular transmission of SVV is mediated by exosomes. The results of co-localization and RT-qPCR studies showed that exosomes harbor SVV and enable the virus to proliferate in both susceptible and non-susceptible cells. Furthermore, the replication of SVV was inhibited when IBRS-2 cells were treated with interfering RNA Rab27a and exosome inhibitor GW4869. Finally, neutralization experiments were performed to further verify whether the virus was encapsulated by the exosomes that mediated transmission between cells. It was found that exosome-mediated intercellular transmission was not blocked by SVV-specific neutralizing antibodies. This study reveals a new transmission route of SVV and provides clear evidence regarding the pathogenesis of SVV, information which can also be useful for identifying therapeutic interventions.
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Exosomas/virología , Infecciones por Picornaviridae/veterinaria , Picornaviridae/fisiología , Enfermedades de los Porcinos/transmisión , Animales , Infecciones por Picornaviridae/transmisión , Infecciones por Picornaviridae/virología , Sus scrofa , Porcinos , Enfermedades de los Porcinos/virologíaRESUMEN
African swine fever (ASF) is an infectious disease characterized by hemorrhagic fever, which is highly pathogenic and causes severe mortality in domestic pigs. It is caused by the African swine fever virus (ASFV). ASFV is a large DNA virus and primarily infects porcine monocyte macrophages. The interaction between ASFV and host macrophages is the major reason for gross pathological lesions caused by ASFV. Necroptosis is an inflammatory programmed cell death and plays an important immune role during virus infection. However, whether and how ASFV induces macrophage necroptosis and the effect of necroptosis signaling on host immunity and ASFV infection remains unknown. This study uncovered that ASFV infection activates the necroptosis signaling in vivo and macrophage necroptosis in vitro. Further evidence showed that ASFV infection upregulates the expression of ZBP1 and RIPK3 to consist of the ZBP1-RIPK3-MLKL necrosome and further activates macrophage necroptosis. Subsequently, multiple Z-DNA sequences were predicted to be present in the ASFV genome. The Z-DNA signals were further confirmed to be present and colocalized with ZBP1 in the cytoplasm and nucleus of ASFV-infected cells. Moreover, ZBP1-mediated macrophage necroptosis provoked the extracellular release of proinflammatory cytokines, including TNF-α and IL-1ß induced by ASFV infection. Finally, we demonstrated that ZBP1-mediated necroptosis signaling inhibits ASFV replication in host macrophages. Our findings uncovered a novel mechanism by which ASFV induces macrophage necroptosis by facilitating Z-DNA accumulation and ZBP1 necrosome assembly, providing significant insights into the pathogenesis of ASFV infection.
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African swine fever virus (ASFV) infection usually causes viremia within a few days. However, the metabolic changes in pig serum after ASFV infection remain unclear. In this study, serum samples collected from ASFV-infected pigs at different times were analyzed using pseudotargeted metabolomics method. Metabolomic analysis revealed the dopaminergic synapse pathway has the highest rich factor in both ASFV5 and ASFV10 groups. By disrupting the dopamine synaptic pathway, dopamine receptor antagonists inhibited ASFV replication and L-dopa promoted ASFV replication. In addition, guanosine, one of the top20 changed metabolites in both ASFV5 and ASFV10 groups suppressed the replication of ASFV. Taken together, this study revealed the changed serum metabolite profiles of ASFV-infected pigs at various times after infection and verified the effect of the changed metabolites and metabolic pathways on ASFV replication. These findings may contribute to understanding the pathogenic mechanisms of ASFV and the development of target drugs to control ASF.
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African swine fever (ASF) is a severe infectious disease that has a high global prevalence. The fatality rate of pigs infected with ASF virus (ASFV) is close to 100%; in the absence of a safe and reliable commercial vaccine, this poses a threat to the global pig industry and public health. To better understand the interaction of ASFV with its host, isobaric tags for relative and absolute quantitation combined with liquid chromatography-mass spectrometry was used to conduct quantitative proteomic analysis of bone marrow-derived macrophage cells infected with ASFV. Overall, 4579 proteins were identified; 286 of these were significantly upregulated and 69 were significantly downregulated after ASFV infection. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and protein-protein interaction network analyses were used to obtain insights into the dynamics and complexity of the ASFV-host interaction. In addition, immunoblotting revealed that the expression of PIK3AP1, RNF114, and FABP5 was upregulated and that of TRAM1 was downregulated after ASFV infection. Overexpression of PIK3AP1 and RNF114 significantly inhibited ASFV replication in vitro, but the suppressive effect of PIK3AP1 on ASFV replication was independent of the PI3K-Akt pathway. Further studies confirmed that ASFV MGF360-9L interacts with PIK3AP1 to reduce its protein expression level. Moreover, LY294002, an inhibitor of the PI3K-Akt pathway, inhibited ASFV replication, indicating the importance of the PI3K-Akt pathway in ASFV infection. This study identified the network of interactions between ASFV and host cells and provides a reference for the development of anti-ASFV strategies and for studying the potential mechanisms and pathogenesis of ASFV infection.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Porcinos , Animales , Virus de la Fiebre Porcina Africana/genética , Fosfatidilinositol 3-Quinasas , Proteínas Proto-Oncogénicas c-akt , Proteómica , Replicación ViralRESUMEN
African swine fever virus (ASFV) infection causes African swine fever (ASF), a virulent infectious disease that threatens the safety of livestock worldwide. Studies have shown that MGF360-9 L is important for the virulence of ASFV and the host protein HS1-associated protein X-1 (HAX1) plays an important role in viral pathogenesis. This study aimed to clarify the mechanism by which HAX1 mediates ASFV replication through interactions with MGF360-9 L. The regions of interaction between MGF360-9 L and HAX1 were predicted and validated. HAX1 overexpression and RNA interference studies revealed that HAX1 is a host restriction factor that suppresses ASFV replication. Moreover, HAX1 expression was inhibited in ASFV-infected mature bone marrow-derived macrophages, and infection with the virulent MGF360-9 L gene deletion strain (∆MGF360-9 L) attenuated the inhibitory effect of the wild-type strain (WT) on HAX1 expression, suggesting a complex regulatory relationship between MGF360-9 L and HAX1. Furthermore, the E3 ubiquitin ligase RNF114 interacted with MGF360-9 L and HAX1, MGF360-9 L degraded HAX1 through the ubiquitin-proteasome pathway, and RNF114 facilitated the degradation of HAX1 by MGF360-9L-linked K48 ubiquitin chains through the ubiquitin-proteasome pathway, thereby facilitating ASFV replication. In conclusion, this study has enriched our understanding of the regulatory networks between ASFV proteins and host proteins and provided a reference for investigation into the pathogenesis and immune escape mechanism of ASFV.
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African swine fever (ASF) has brought excellent barriers to swine production in China and the world. Studies have shown that extracellular vesicles mediate the RNA and protein spread of pathogenic microorganisms and RNA and proteins. After infection by pathogenic microorganisms causes significant differences in the proteins contained within extracellular vesicles. Based on the above studies, the extracellular vesicles were extracted from ASF virus (ASFV)-infected swine plasma. And qPCR, western blot, and confocal experiment were carried out. The research shows that extracted extracellular vesicles significantly promote the replication of ASFV in susceptible and non-susceptible cells Proteomics analysis of the extracellular vesicle proteins revealed that ASFV infection could cause significant differences in the protein profile. This study demonstrates that extracellular vesicles play a critical role in ASFV replication and transmission and cause significant differences in the protein profile encapsulated in extracellular vesicles.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Vesículas Extracelulares , Fiebre Porcina Africana/metabolismo , Fiebre Porcina Africana/patología , Virus de la Fiebre Porcina Africana/genética , Virus de la Fiebre Porcina Africana/metabolismo , Animales , Vesículas Extracelulares/metabolismo , Proteómica , Porcinos , Replicación ViralRESUMEN
African swine fever (ASF) is a contagious and lethal hemorrhagic disease in pigs; its spread results in huge economic losses to the global pig industry. ASF virus (ASFV) is a large double-stranded DNA virus encoding >150 open reading frames. Among them, ASFV-encoded D1133L was predicted to be a helicase but its specific function remains unknown. Since virus-host protein interactions are key to understanding viral protein function, we used co-immunoprecipitation combined with liquid chromatography-mass spectrometry to investigate D1133L. This study describes the interaction network of ASFV D1133L protein in porcine kidney PK-15 cells. Overall, 1,471 host proteins that potentially interact with D1133L are identified. Based on these host proteins, a protein-protein network was constructed. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses showed that cellular D1133L-interacted proteins are involved in the ribosome, spliceosome, RNA transport, oxidative phosphorylation, proteasome, and DNA replication. Vimentin (VIM), tripartite motif-containing protein 21 (TRIM21), and Tu translation elongation factor (TUFM) were confirmed to interact with D1133L in vitro. VIM or TRIM21 overexpression significantly promoted ASFV replication, but TUFM overexpression significantly inhibited ASFV replication. These results help elucidate the specific functions of D1133L and the potential mechanisms underlying ASFV replication.
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Foot-and-mouth disease (FMD) is induced by FMD virus (FMDV) and characterized by fever and vesicular (blister-like) lesions. However, the exact composition of the vesicular fluid in pigs infected with FMDV remains unclear. To identify and analyze the components of the vesicular fluid in FMDV-infected domestic pigs, the fluid was collected and subjected to mass spectrometry. Further analyses were conducted using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genome (KEGG), and protein-protein interaction (PPI). Quantitative ELISA kit for TNF-α, and IFN-α, IFN-ß, IL-6, IL-10, IL-1ß, and IFN-γ were used to verify the mass spectrometry results. Results showed that 937 proteins were identified in the vesicular fluid from swine after FMDV infection, and bioinformatics analysis indicated that these proteins are related to the innate immune and inflammation pathways. The levels of cytokines involved in the disease-related pathways, tumor necrosis factors, and IL-6 in the fluid samples were significantly increased. This study identified and analyzed the composition of vesicular fluid in pigs after FMD infection for the first time and provided interesting information that help understand the infection and pathogenesis mechanism of FMD. These information will eventually contribute to the prevention and control of FMD.
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African swine fever (ASF)-an aggressive infectious disease caused by the African swine fever virus (ASFV)-is significantly unfavorable for swine production. ASFV has a complex structure and encodes 150-167 proteins; however, the function of most of these proteins is unknown. This study identified ASFV MGF360-9L as a negative regulator of the interferon (IFN)-ß signal. Further evidence showed that MGF360-9L interacts with signal transducer and activator of transcription (STAT) 1 and STAT2 and degrades STAT1 and STAT2 through apoptosis and ubiquitin-proteasome pathways, respectively. Subsequently, the activation of IFN-ß signaling was inhibited. Naturally isolated or genetically manipulated live attenuated viruses are known to protect against the virulent parental ASFV strains. Therefore, through homologous recombination, we deleted MGF360-9L from the virulent ASFV CN/GS/2018 strain to construct a recombinant strain, ASFV-Δ360-9L. Compared with the parent ASFV CN/GS/2018 strain, the replication level of ASFV-Δ360-9L decreased in primary porcine alveolar macrophage cultures at 24 h postinfection, but the difference is unlikely to be biologically relevant. Notably, ASFV-Δ360-9L was partially attenuated in pigs. To our knowledge, this study is the first to uncover the function of MGF360-9L during ASFV infection. MGF360-9L inhibits IFN-ß signaling through the targeted degradation of STAT1 and STAT2. Furthermore, MGF360-9L is a key virulence gene of ASFV. Our findings reveal a new mechanism by which ASFV inhibits host antiviral response; this might facilitate the development of live attenuated ASFV vaccines. IMPORTANCE African swine fever-an acute, febrile, hemorrhagic, highly contacting, and highly lethal disease caused by African swine fever virus (ASFV)-jeopardizes the global pig industry. Understanding the mechanism ASFV employs to evade host defense during infection is essential for developing targeted drugs and vaccines against ASFV. To our knowledge, this study identifies the mechanism of innate immunity against by MGF360-9L and the effect of MGF360-9L on ASFV pathogenicity. The results showed that MGF360-9L may help ASFV escape the host immunity by degrading STAT1 and STAT2 and thus inhibiting IFN-ß signaling. MGF360-9L is also an important virulence factor of ASFV. The deletion of MGF360-9L reduces ASFV virulence in pigs. This study explored a new mechanism of ASFV against innate immunity and identified a new ASFV virulence factor; these findings may guide the development of live attenuated ASFV vaccines.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Animales , Virus de la Fiebre Porcina Africana/genética , Macrófagos , Transducción de Señal , Porcinos , Proteínas Virales/genética , Factores de Virulencia/genética , Quinasas Janus/metabolismo , Factores de Transcripción STAT/metabolismoRESUMEN
The porcine reproductive and respiratory syndrome virus (PRRSV) is the pathogen causing epidemics of porcine reproductive and respiratory syndrome (PRRS), and is present in every major swine-farming country in the world. Previous studies have demonstrated that PRRSV infection leads to a range of consequences, such as persistent infection, secondary infection, and co-infection, and is common among pigs in the field. In recent years, coinfection of PRRSV and other porcine pathogens has occurred often, making it more difficult to define and diagnose PRRSV-related diseases. The study of coinfections may be extremely suitable for the current prevention and control in the field. However, there is a limited understanding of coinfection. Therefore, in this review, we have focused on the epidemiology of PRRSV coinfection with other pathogens in swine, both in vivo and in vitro.