The present study delves into the cellular mechanisms underlying the antiviral effects of dehydrodiisoeugenol(DEH) by focusing on the transcription factor EB(TFEB)/autophagy-lysosome pathway. The cell counting kit-8(CCK-8) was utilized to assess the impact of DEH on the viability of human non-small cell lung cancer cells(A549). The inhibitory effect of DEH on the replication of influenza A virus(H1N1) was determined by real-time quantitative polymerase chain reaction(RT-qPCR). Western blot was employed to evaluate the influence of DEH on the expression level of the H1N1 virus nucleoprotein(NP). The effect of DEH on the fluorescence intensity of NP was examined by the immunofluorescence assay. A mouse model of H1N1 virus infection was established via nasal inhalation to evaluate the therapeutic efficacy of 30 mg·kg~(-1) DEH on H1N1 virus infection. RNA sequencing(RNA-seq) was performed for the transcriptional profiling of mouse embryonic fibroblasts(MEFs) in response to DEH. The fluorescent protein-tagged microtubule-associated protein 1 light chain 3(LC3) was used to assess the autophagy induced by DEH. Western blot was employed to determine the effect of DEH on the autophagy flux of LC3Ⅱ/LC3Ⅰ under viral infection conditions. Lastly, the role of TFEB expression in the inhibition of DEH against H1N1 infection was evaluated in immortalized bone marrow-derived macrophage(iBMDM), both wild-type and TFEB knockout. The results revealed that the half-maximal inhibitory concentration(IC_(50)) of DEH for A549 cells was(87.17±0.247)μmol·L~(-1), and DEH inhibited H1N1 virus replication in a dose-dependent manner in vitro. Compared with the H1N1 virus-infected mouse model, the treatment with DEH significantly improved the body weights and survival time of mice. DEH induced LC3 aggregation, and the absence of TFEB expression in iBMDM markedly limited the ability of DEH to counteract H1N1 virus replication. In conclusion, DEH exerts its inhibitory activity against H1N1 infection by activating the TFEB/autophagy-lysosome pathway.
Influenza A Virus, H1N1 Subtype/genetics* ; Animals ; Autophagy/drug effects* ; Humans ; Mice ; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/genetics* ; Influenza, Human/metabolism* ; Lysosomes/metabolism* ; Orthomyxoviridae Infections/genetics* ; Eugenol/pharmacology* ; Antiviral Agents/pharmacology* ; Virus Replication/drug effects* ; A549 Cells ; Male

Vaccination is the most effective measure for reducing and preventing influenza and related complications. In this study, we analyzed the mutation trend and the antigen dominant site changes of the amino acid sequence of hemagglutinin subunit 1 (HA1) of human influenza A virus (IAV) in the northern hemisphere from 2012 to 2022. According to the HA1 sequences of A/Darwin/6/2021 (H3N2) and A/Wisconsin/588/2019 (H1N1) recommended by the World Health Organization in the 2022 influenza season in northern hemisphere, we employed the mosaic algorithm to design three Mosaic-HA1 antigens through stepwise substitution. Mosaic-HA1 was expressed and purified in 293F cells and then mixed with the alum adjuvant at a volume ratio of 1:1. The mixture was used to immunize BALB/c mice, and the immunogenicity was evaluated. Enzyme-linked immunosorbent assay showed that Mosaic-HA1 induced the production of IgG targeting two types of HA1, the specific IgG titers for binding to H3 protein and H1 protein reached 10⁵ and 10³ respectively. The challenge test showed that Mosaic-HA1 protected mice from H3N2 or H1N1. This study designs the vaccines by recombination of major antigenic sites in different subtypes of IAV, giving new insights into the development of multivalent subunit vaccines against influenza.
Animals ; Influenza A Virus, H1N1 Subtype/genetics* ; Influenza A Virus, H3N2 Subtype/genetics* ; Mice, Inbred BALB C ; Mice ; Influenza Vaccines/genetics* ; Hemagglutinin Glycoproteins, Influenza Virus/genetics* ; Humans ; Antibodies, Viral/blood* ; Antigens, Viral/genetics* ; Immunoglobulin G/immunology* ; Female ; Orthomyxoviridae Infections/prevention & control* ; HEK293 Cells

Influenza B virus (IBV) is more likely to cause complications than influenza A virus (IAV) and even causes higher disease burden than IAV in a certain season, but IBV has received less attention. In order to analyze the genetic evolution characteristics of the clinical strain IBV (B/Guangxi-Jiangzhou/1352/2018), we constructed genetic evolution trees and analyzed the homology and different amino acids of hemagglutinin and neuraminidase referring to the vaccine strains recommended by World Health Organization (WHO). We found that strain B/Guangxi-Jiangzhou/1352/2018 was free of interlineage reassortment and poorly matched with the vaccine strain B/Colorado/06/2017 of the same year. We also determined the median lethal dose (LD₅₀) and the pathogenicity of strain B/Guangxi-Jiangzhou/1352/2018 in mice. The results showed that the LD₅₀ was 10^5.9 TCID₅₀ (median tissue culture infective dose), the IBV titer in the lungs reached peak 1 d post infection and the mRNA level of the most of inflammatory cytokines in the lungs reached peak 12 h post infection. The alveoli in the lungs were severely damaged and a large number of inflammatory cells were infiltrated post infection. The study demonstrated that the clinical strain IBV (B/Guangxi-Jiangzhou/1352/2018) could infect mice and induce typical lung inflammation. This will facilitate the research on the pathogenesis and transmission mechanism of IBV, and provide an ideal animal model for evaluation of new vaccines, antiviral and anti-inflammatory drug.
Amino Acids/genetics* ; Animals ; Antiviral Agents/pharmacology* ; China ; Cytokines/metabolism* ; Hemagglutinins/metabolism* ; Humans ; Influenza B virus/pathogenicity* ; Influenza, Human/virology* ; Mice ; Neuraminidase/genetics* ; Orthomyxoviridae Infections/virology* ; Phylogeny ; RNA, Messenger/metabolism* ; Virulence/genetics*

Based on Janus kinase 1/2-signal transducer and activator of transcription 1(JAK1/2-STAT1) signaling pathway, this study explored the immune mechanism of Maxing Shigan Decoction in alleviating the lung tissue and colon tissue damage in mice infected with influenza virus. The influenza virus infection was induced in mice by nasal drip of influenza virus. The normal group, model group, oseltamivir group, antiviral granule group, and Maxing Shigan Decoction group were designed. After intragastric administration of corresponding drugs or normal saline for 3 or 7 days, the body mass was measured, and lung index, spleen index, and thymus index were calculated. Based on hematoxylin-eosin(HE) staining, the pathological changes of lung tissue and colon tissue were observed. Enzyme-linked immunosorbent assay(ELISA) was used to detect serum levels of inflammatory factors interleukin-8(IL-8) and interferon-γ(IFN-γ), Western blot and real-time quantitative polymerase chain reaction(RT-qPCR) to determine the protein and mRNA levels of JAK1, JAK2, STAT1, interferon regulatory factor 9(IRF9), and IFN-γ in lung tissue and colon tissue. The results showed that after 3 and 7 days of administration, the body mass, spleen index, and thymus index were lower(P<0.05 or P<0.01), and the lung index was higher(P<0.01) in the model group than in the normal group. Moreover, the model group showed congestion, edema, and infiltration of a large number of lymphocytes and macrophages in the lung tissue, irregular structure of colon mucosa, ulceration and shedding of epithelial cells, and infiltration of a large number of inflammatory cells. The model group had higher levels of serum IFN-γ(P<0.01), higher protein and mRNA expression of JAK1, JAK2, STAT1, IRF9, IFN-γ in lung tissue(P<0.05 or P<0.01), higher level of JAK2 protein in colon tissue(P<0.01), and higher protein and mRNA levels of STAT1 and IRF9(P<0.05 or P<0.01) than the normal group. Compared with the model group, Maxing Shigan Decoction group had high body mass, spleen index, and thymus index(P<0.05 or P<0.01), low lung index(P<0.05 or P<0.01), and significant alleviation of pathological injury in lung and colon. Moreover, lower serum level of IFN-γ(P<0.05 or P<0.01), protein and mRNA levels of JAK1, JAK2, STAT1, IRF9, and IFN-γ in lung tissue(P<0.05 or P<0.01), JAK2 protein level in colon tissue(P<0.01), and protein and mRNA levels of STAT1 and IRF9(P<0.05 or P<0.01) were observed in the Maxing Shigan Decoction group than in the model group. After 3 days of administration, the level of serum IL-8 in the model group was significantly higher than that in the normal group(P<0.01), and the level in the Maxing Shigan Decoction group was significantly reduced(P<0.01). In conclusion, Maxing Shigan Decoction can significantly up-regulate body mass, spleen index, and thymus index, down-regulate lung index, reduce the levels of IL-8 and IFN-γ, and down-regulate protein and mRNA levels of JAK1, JAK2, STAT1, IRF9, and IFN-γ in lung tissue and protein and mRNA levels of JAK2, STAT1, and IRF9 in colon tissue, and alleviate pathological damage of lung tissue and colon tissue. The mechanism is the likelihood that it inhibits the activation of JAK1/2-STAT1 signaling pathway to alleviate the damage to lung and colon tissue damage.
Mice ; Animals ; Humans ; Janus Kinase 1/genetics* ; STAT1 Transcription Factor/genetics* ; Influenza, Human ; Interleukin-8 ; Signal Transduction ; Orthomyxoviridae Infections ; Interferon-gamma ; Lung ; RNA, Messenger ; Orthomyxoviridae ; Colon

Objective: Interferon-induced transmembrane protein 3 (IFITM3) is an important member of the IFITM family. However, the molecular mechanisms underlying its antiviral action have not been completely elucidated. Recent studies on IFITM3, particularly those focused on innate antiviral defense mechanisms, have shown that IFITM3 affects the body's adaptive immune response. The aim of this study was to determine the contribution of IFITM3 proteins to immune control of influenza infection . Methods: We performed proteomics, flow cytometry, and immunohistochemistry analysis and used bioinformatics tools to systematically compare and analyze the differences in natural killer (NK) cell numbers, their activation, and their immune function in the lungs of -/- and wild-type mice. Results: -/- mice developed more severe inflammation and apoptotic responses compared to wild-type mice. Moreover, the NK cell activation was higher in the lungs of -/- mice during acute influenza infection. Conclusions Based on our results, we speculate that the NK cells are more readily activated in the absence of IFITM3, increasing mortality in -/- mice.
Acute Disease ; Animals ; Disease Models, Animal ; Female ; Humans ; Influenza, Human ; virology ; Male ; Membrane Proteins ; genetics ; metabolism ; Mice ; Mice, Inbred C57BL ; Orthomyxoviridae Infections ; veterinary ; virology ; Rodent Diseases ; virology

Swine influenza viruses (SwIVs) cause considerable morbidity and mortality in domestic pigs, resulting in a significant economic burden. Moreover, pigs have been considered to be a possible mixing vessel in which novel strains loom. Here, we developed and evaluated a novel M2e-multiple antigenic peptide (M2e-MAP) as a supplemental antigen for inactivated H3N2 vaccine to provide cross-protection against two main subtypes of SwIVs, H1N1 and H3N2. The novel tetra-branched MAP was constructed by fusing four copies of M2e to one copy of foreign T helper cell epitopes. A high-yield reassortant H3N2 virus was generated by plasmid based reverse genetics. The efficacy of the novel H3N2 inactivated vaccines with or without M2e-MAP supplementation was evaluated in a mouse model. M2e-MAP conjugated vaccine induced strong antibody responses in mice. Complete protection against the heterologous swine H1N1 virus was observed in mice vaccinated with M2e-MAP combined vaccine. Moreover, this novel peptide confers protection against lethal challenge of A/Puerto Rico/8/34 (H1N1). Taken together, our results suggest the combined immunization of reassortant inactivated H3N2 vaccine and the novel M2e-MAP provided cross-protection against swine and human viruses and may serve as a promising approach for influenza vaccine development.
Animals ; Antibodies, Viral/blood ; Antigens, Viral/genetics/*immunology ; Body Weight ; Cross Protection/*immunology ; Disease Models, Animal ; Epitopes, T-Lymphocyte/genetics/immunology ; Female ; Influenza A Virus, H3N2 Subtype/genetics/*immunology ; Influenza Vaccines/*immunology ; Mice ; Mice, Inbred BALB C ; Orthomyxoviridae Infections/*immunology/mortality/pathology/prevention & control ; Peptides/genetics/*immunology ; Random Allocation ; Survival Analysis ; Vaccines, Synthetic/immunology ; Virus Replication

A novel H17N10 subtype of the influenza A viruses was found in bats in 2012. Protein sequence and structural analyses revealed that the HA17 and NA10 proteins of this strain are different from corresponding ones in known influenza A subtype viruses. Both HA17 and NA10 proteins cannot bind to sialic acid,which indicates that they may have novel functions. This article briefly describes the state of current research into the H17N10 subtype of bat influenza A virus.
Animals ; Chiroptera ; virology ; Influenza A virus ; classification ; genetics ; isolation & purification ; metabolism ; Orthomyxoviridae Infections ; veterinary ; virology ; Viral Proteins ; genetics ; metabolism

Novel reassortant H3N2 swine influenza viruses (SwIV) with the matrix gene from the 2009 H1N1 pandemic virus have been isolated in many countries as well as during outbreaks in multiple states in the United States, indicating that H3N2 SwIV might be a potential threat to public health. Since southern China is the world's largest producer of pigs, efficient vaccines should be developed to prevent pigs from acquiring H3N2 subtype SwIV infections, and thus limit the possibility of SwIV infection at agricultural fairs. In this study, a high-growth reassortant virus (GD/PR8) was generated by plasmid-based reverse genetics and tested as a candidate inactivated vaccine. The protective efficacy of this vaccine was evaluated in mice by challenging them with another H3N2 SwIV isolate [A/Swine/Heilongjiang/1/05 (H3N2) (HLJ/05)]. Prime and booster inoculation with GD/PR8 vaccine yielded high-titer serum hemagglutination inhibiting antibodies and IgG antibodies. Complete protection of mice against H3N2 SwIV was observed, with significantly reduced lung lesion and viral loads in vaccine-inoculated mice relative to mock-vaccinated controls. These results suggest that the GD/PR8 vaccine may serve as a promising candidate for rapid intervention of H3N2 SwIV outbreaks in China.
Animals ; Female ; Influenza A Virus, H3N2 Subtype/*genetics/immunology ; Influenza Vaccines/genetics/immunology/*therapeutic use ; Mice ; Mice, Inbred BALB C ; Orthomyxoviridae Infections/immunology/*prevention & control/virology ; Reassortant Viruses/genetics/immunology ; Reverse Genetics/methods/*veterinary ; Swine ; Swine Diseases/immunology/*prevention & control/virology ; Vaccines, Inactivated ; Virus Replication

Animals ; Asian Continental Ancestry Group ; Chickens ; China ; epidemiology ; Cytokines ; metabolism ; Genetic Variation ; Genotype ; Humans ; Influenza A Virus, H7N9 Subtype ; classification ; genetics ; pathogenicity ; Influenza A Virus, H9N2 Subtype ; genetics ; Influenza in Birds ; transmission ; virology ; Influenza, Human ; ethnology ; transmission ; virology ; Mice, Inbred BALB C ; Molecular Sequence Data ; Orthomyxoviridae Infections ; metabolism ; mortality ; virology ; Phylogeny ; Seasons ; Survival Rate ; Virulence ; genetics

Eleven proteins encoded by influenza A viruses play different roles in host receptor recognition, cross-species transmission, virus replication, pathogenicity, and induction of host immune responses. Understanding of the pathogenic mechanism of mutations in influenza A virus-encoded proteins could offer new targets for the development of universal vaccines and effective drugs against highly pathogenic influenza viruses. Based mainly on the current literature, this article is intended to provide a comprehensive analysis of progresses in amino acid variations in influenza A virus-encoded proteins and their relationships to pathogenicity as well as cross-species transmissibility.
Amino Acid Sequence ; Animals ; Genetic Variation ; Humans ; Influenza A virus ; genetics ; pathogenicity ; Influenza, Human ; transmission ; virology ; Mice ; Mutation ; Orthomyxoviridae Infections ; transmission ; virology ; Viral Proteins ; genetics ; physiology