Search Results (2,262)

Měnglà virus (MLAV) is a member of the genus Dianlovirus in the family Filoviridae, which also includes Ebola virus (EBOV) and Marburg virus (MARV). Whether MLAV poses a threat to human health is uncertain. However, the MLAV VP35 and VP40 proteins can impair IFNα/β gene expression and block IFNα/β-induced Jak-STAT signaling, respectively, suggesting the capacity to counteract human innate immune defenses. In this study, MLAV VP40 is demonstrated to impair the Sendai virus (SeV)-induced activation of the IFNβ promoter. Inhibition is independent of the MLAV VP40 PPPY late-domain motif that interacts with host proteins possessing WW-domains to promote viral budding. Similar IFNβ promoter inhibition was not detected for EBOV or MARV VP40. MLAV VP40 exhibited lesser capacity to inhibit TNFα activation of an NF-κB reporter gene. MLAV VP40 impaired IFNβ promoter activation by an over-expressed, constitutively active form of RIG-I and by the over-expressed IRF3 kinases TBK1 and IKKε. However, MLAV VP40 did not inhibit IFNβ promoter activation by constitutively active IRF3 5D. Consistent with these findings, MLAV VP40 inhibited SeV-induced IRF3 phosphorylation. Although IRF3 phosphorylation occurs in the cytoplasm, MLAV VP40 exhibits substantial nuclear localization, accumulating in foci in HeLa cell nuclei. In contrast, the VP40 of EBOV and MARV exhibited lower degrees of nuclear localization and did not accumulate in foci. MLAV VP40 interacts with importin alpha-1 (IMPα1), suggesting entry via the IMPα/IMPβ nuclear import pathway. Cumulatively, these data identify novel features that distinguish MLAV VP40 from its homologues in EBOV and MARV. Full article

Recently, essential rose oils and rose products have gained increasing importance in both the cosmetic and food industries, as well as in the composition of medicinal products. We investigated the in vitro antiviral activity of essential oil and floral water from Rosa damascena Mill against herpes simplex virus type 1 (HSV-1) infection in rabbit retinal cells (RRCs). The composition of the main chemical components in the rose essential oil was determined by means of gas chromatographic analysis. The effect on the viral replication cycle was determined using the cytopathic effect (CPE) inhibition assay. The virucidal activity, the effect on the adsorption stage of the virus to the host cell, and the protective effect on healthy cells were evaluated using the endpoint dilution method. The effects were determined as deviation in the viral titer, Δlg, for the treated cells from the one for the untreated viral control. The identified main active components of rose oil are geraniol (28.73%), citronellol (21.50%), nonadecane (13.13%), nerol (5.51%), heneicosane (4.87%), nonadecene (3.93), heptadecane (2.29), farnesol (2.11%), tricosane (1.29%), eicosane (1.01%), and eugenol (0.85%). The results demonstrated that both rose products do not have a significant effect on the virus replication but directly affect the viral particles and reduce the viral titer by Δlg = 3.25 for floral water and by Δlg = 3.0 for essential oil. Significant inhibition of the viral adsorption stage was also observed, leading to a decrease in the viral titers by Δlg = 2.25 for floral water and by Δlg = 2.0 for essential oil. When pretreating healthy cells with rose products, both samples significantly protected them from subsequent infection with HSV-1. This protective effect was more pronounced for the oil (Δlg = 2.5) compared to the one for the floral water (Δlg = 2.0). We used the in silico molecular docking method to gain insight into the mechanism of hindrance of viral adsorption by the main rose oil compounds (geraniol, citronellol, nerol). These components targeted the HSV-1 gD interaction surface with nectin-1 and HVEM (Herpesvirus Entry Mediator) host cell receptors, at N-, C-ends, and N-end, respectively. These findings could provide a structural framework for further development of anti-HSV-1 therapeutics. Full article

This paper introduces a novel fractional-order model using the Caputo derivative operator to investigate the virus dynamics of adaptive immune responses. Two infection routes, namely cell-to-cell and virus-to-cell transmissions, are incorporated into the dynamics. Our research establishes the existence and uniqueness of positive and bounded solutions through the application of the generalized mean-value theorem and Banach fixed-point theory methods. The fractional-order model is shown to be Ulam–Hyers stable, ensuring the model’s resilience to small errors. By employing the normalized forward sensitivity method, we identify critical parameters that profoundly influence the transmission dynamics of the fractional-order virus model. Additionally, the framework of optimal control theory is used to explore the characterization of optimal adaptive immune responses, encompassing antibodies and cytotoxic T lymphocytes (CTL). To assess the influence of memory effects, we utilize the generalized forward–backward sweep technique to simulate the fractional-order virus dynamics. This study contributes to the existing body of knowledge by providing insights into how the interaction between virus-to-cell and cell-to-cell dynamics within the host is affected by memory effects in the presence of optimal control, reinforcing the invaluable synergy between fractional calculus and optimal control theory in modeling within-host virus dynamics, and paving the way for potential control strategies rooted in adaptive immunity and fractional-order modeling. Full article

Daphnis nerii cypovirus-23 (DnCPV-23) is a new type of cypovirus that has a lethal effect on many species of Sphingidae pests. DnCPV-23 can replicate in Spodoptera frugiperda Sf9 cells, but the replication characteristics of the virus in this cell line are still unclear. To determine the replication characteristics of DnCPV-23 in Sf9 cells, uninfected Sf9 cells and Sf9 cells at 24 and 72 h after DnCPV-23 infection were collected for transcriptome analysis. Compared to uninfected Sf9 cells, a total of 188 and 595 differentially expressed genes (DEGs) were identified in Sf9 cells collected at 24 hpi and 72 h, respectively. KEGG analyses revealed that 139 common DEGs in two treatment groups were related to nutrition and energy metabolism-related processes, cell membrane integrity and function-related pathways, detoxification-related pathways, growth and development-related pathways, and so on. We speculated that these cellular processes might be manipulated by viruses to promote replication. This study provides an important basis for further in-depth research on the mechanism of interaction between viruses and hosts. It provides additional basic information for the future exploitation of DnCPV-23 as a biological insecticide. Full article

The rabies virus (RABV) phosphoprotein (P protein) has multiple functions, including acting as the essential non-catalytic cofactor of the viral polymerase (L protein) for genome replication and transcription; the principal viral antagonist of the interferon (IFN)-mediated innate immune response; and the chaperone for the viral nucleoprotein (N protein). Although P protein is known to undergo phosphorylation by cellular kinases, the location and functions of the phosphorylation sites remains poorly defined. Here, we report the identification by mass-spectrometry (MS) of residues of P protein that are modified by phosphorylation in mammalian cells, including several novel sites. Analysis of P protein with phospho-mimetic and phospho-inhibitory mutations of three novel residues/clusters that were commonly identified by MS (Ser48, Ser183/187, Ser217/219/220) indicate that phosphorylation at each of these sites does not have a major influence on nuclear trafficking or antagonistic functions toward IFN signalling pathways. However, phosphorylation of Ser48 in the N-terminus of P protein impaired function in transcription/replication and in the formation of replication structures that contain complexes of P and N proteins, suggestive of altered interactions of these proteins. The crystal structure of P protein containing the S48E phospho-mimetic mutation indicates that Ser48 phosphorylation facilitates the binding of residues 41–52 of P protein into the RNA-binding groove of non-RNA-bound N protein (N⁰), primarily through the formation of a salt bridge with Arg434 of N protein. These data indicate that Ser48 modification regulates the cycling of P-N⁰ chaperone complexes that deliver N protein to RNA to enable transcription/replication, such that enhanced interaction due to S48E phospho-mimetic mutation reduces N protein delivery to the RNA, inhibiting subsequent transcription/replication processes. These data are, to our knowledge, the first to implicate phosphorylation of RABV P protein in conserved replication functions of the P gene. Full article

The expanding distribution and geographic range of mosquitoes have potentially contributed to increased flaviviral dissemination and transmission. Despite the growing burden of flaviviral infections, there are no effective antiviral treatments or vaccines, highlighting the need for novel therapeutic targets. Tetraspanins, a superfamily of transmembrane domain glycoproteins involved in cellular organization, signaling, and protein–protein interactions have been recognized as potential mediators of flaviviral infection and transmission. While their roles in vertebrate hosts have been explored, their involvement in flaviviral replication and dissemination within medically important vectors remains poorly understood. In this study, we investigated the role of arthropod tetraspanins in mosquito cells and extracellular vesicles (EVs) derived from cells infected with Zika virus (ZIKV) and dengue virus (serotype 2; DENV2). Among several of the tetraspanins analyzed, only CD151 was significantly upregulated in both mosquito cells and in EVs derived from ZIKV/DENV2-infected cells. RNAi-mediated silencing of CD151 led to a marked reduction in viral burden, suggesting its crucial role in flavivirus replication. Inhibition of EV biogenesis using GW4869 further demonstrated that EV-mediated viral transmission contributes to flavivirus propagation. Additionally, co-immunoprecipitation and immunofluorescence analyses revealed direct interactions between CD151 and ZIKV NS2B and DENV2 capsid proteins. Overall, our findings highlight the functional importance of mosquito CD151 in the replication and transmission of ZIKV and DENV2. This study provides new insights into the molecular mechanisms of flaviviral infection in mosquitoes and suggests that targeting vector tetraspanins may offer a potential approach to controlling mosquito-borne flaviviruses. Full article

Multivalent lectin–glycan interactions (MLGIs) are vital for viral infection, cell-cell communication and regulation of immune responses. Their structural and biophysical data are thus important, not only for providing insights into their underlying mechanisms but also for designing potent glycoconjugate therapeutics against target MLGIs. However, such information remains to be limited for some important MLGIs, significantly restricting the research progress. We have recently demonstrated that functional nanoparticles, including ∼4 nm quantum dots and varying sized gold nanoparticles (GNPs), densely glycosylated with various natural mono- and oligo- saccharides, are powerful biophysical probes for MLGIs. Using two important viral receptors, DC-SIGN and DC-SIGNR (together denoted as DC-SIGN/R hereafter), as model multimeric lectins, we have shown that α-mannose and α-manno-α-1,2-biose (abbreviated as Man and DiMan, respectively) coated GNPs not only can provide sensitive measurement of MLGI affinities but also reveal critical structural information (e.g., binding site orientation and mode) which are important for MLGI targeting. In this study, we produced mannuronic acid (ManA) coated GNPs (GNP-ManA) of two different sizes to probe the effect of glycan modification on their MLGI affinity and antiviral property. Using our recently developed GNP fluorescence quenching assay, we find that GNP-ManA binds effectively to both DC-SIGN/R and increasing the size of GNP significantly enhances their MLGI affinity. Consistent with this, increasing the GNP size also significantly enhances their ability to block DC-SIGN/R-augmented virus entry into host cells. Particularly, ManA coated 13 nm GNP potently block Ebola virus glycoprotein-driven entry into DC-SIGN/R-expressing cells with sub-nM levels of EC₅₀. Our findings suggest that GNP-ManA probes can act as a useful tool to quantify the characteristics of MLGIs, where increasing the GNP scaffold size substantially enhances their MLGI affinity and antiviral potency. Full article

Barley leaf stripe, caused by Pyrenophora graminea (Pg), significantly reduces yields across various regions globally. Understanding the resistance mechanisms of barley to Pg is crucial for advancing disease resistance breeding efforts. In this study, two barley genotypes—highly susceptible Alexis and immune Ganpi2—were inoculated with the highly pathogenic Pg isolate QWC for 7, 14, and 18 days. The number of differentially expressed genes (DEGs) in Alexis was 1350, 1898, and 2055 at 7, 14, and 18 days, respectively, while Ganpi2 exhibited 1195, 1682, and 2225 DEGs at the same time points. Gene expression pattern analysis revealed that Alexis responded more slowly to Pg infection compared to Ganpi2. A comparative analysis identified 457 DEGs associated with Ganpi2’s immunity to Pg. Functional enrichment of these DEGs highlighted the involvement of genes related to plant-pathogen interactions and kinase activity in Pg immunity. Additionally, 20 resistance genes and 24 transcription factor genes were predicted from the 457 DEGs. Twelve candidate genes were selected for qRT-PCR verification, and the results showed that the transcriptomic data was reliable. We conducted cloning of the candidate Pg resistance gene HvLRR_8-1 by the barley cultivar Ganpi2, and the sequence analysis confirmed that the HvLRR_8-1 gene contains seven leucine-rich repeat (LRR) domains and an S_TKc domain. Subcellular localization in tobacco indicates that the HvLRR_8-1 is localized on the cell membrane. Through the functional analysis using virus-induced gene silencing, it was demonstrated that HvLRR_8-1 plays a critical role in regulating barley resistance to Pg. This study represents the first comparative transcriptome analysis of barley varieties with differing responses to Pg infection, providing that HvLRR_8-1 represents a promising candidate gene for improving durable resistance against Pg in cultivated barley. Full article

Nucleocytoplasmic trafficking is a highly regulated process that allows the cell to control the partitioning of proteins and nucleic acids between the cytosolic and nuclear compartments. The Ebola virus minor matrix protein VP24 (eVP24) hijacks this process by binding to a region on the NPI-1 subfamily of karyopherin alpha (KPNA) nuclear importers. This region overlaps with the activated transcription factor STAT1 binding site on KPNAs, preventing STAT1 nuclear localization and activation of antiviral gene transcription. However, the molecular interactions of eVP24-KPNA5 binding that lead to the nuclear localization of eVP24 remain poorly characterized. Here, we show that trafficking of eVP24 into the nucleus by KPNA5 requires simultaneous binding of cargo. We also describe the conformational dynamics of KPNA5 and interactions with eVP24 and cargo nuclear localization sequences (NLS) using biophysical approaches. Our results reveal that eVP24 binding to KPNA5 does not impact cargo NLS binding to KPNA5, indicating that simultaneous binding of both cellular cargo and eVP24 to KPNA5 is likely required for nuclear trafficking. Together, these results provide a biophysical basis for how Ebola virus VP24 protein gains access to the nucleus during Ebola virus infection. Full article

Viral oncolysis is considered a promising cancer treatment method because of its good tolerability and durable anti-tumor effects. Compared with other oncolytic viruses, Newcastle disease virus (NDV) has some distinct advantages. As an RNA virus, NDV does not recombine with the host genome, making it safer compared with DNA viruses and retroviruses; NDV can induce syncytium formation, allowing the virus to spread among cells without exposure to host neutralizing antibodies; and its genome adheres to the hexamer genetic code rule (genome length as a multiple of six nucleotides), ensuring accurate replication, low recombination rates, and high genetic stability. Although wild-type NDV has a killing effect on various tumor cells, its oncolytic effect and working mechanism are diverse, increasing the complexity of generating engineered oncolytic viruses with NDV. This study aims to employ whole-genome CRISPR-Cas9 knockout screening and RNA sequencing to identify putative key regulatory factors involved in the interaction between NDV and human colon cancer HCT116 cells and map their global interaction networks. The results suggests that NDV infection disrupts cellular homeostasis, thereby exerting oncolytic effects by inhibiting cell metabolism and proliferation. Meanwhile, the antiviral immune response triggered by NDV infection, along with the activation of anti-apoptotic signaling pathways, may be responsible for the limited oncolytic efficacy of NDV against HCT116 cells. These findings not only enhance our understanding of the oncolytic mechanism of NDV against colonic carcinoma but also provide potential strategies and targets for the development of NDV-based engineered oncolytic viruses. Full article

Monkeypox virus (MPXV) has caused 148,892 confirmed cases and 341 deaths from 137 countries worldwide, as reported by the World Health Organization (WHO), highlighting the urgent need for effective vaccines to prevent the spread of MPXV. Traditional vaccine development is low-throughput, expensive, time consuming, and susceptible to reversion to virulence. Alternatively, a reverse vaccinology approach offers a rapid, efficient, and safer alternative for MPXV vaccine design. Here, MPXV proteins associated with viral infection were analyzed for immunogenic epitopes to design multi-epitope vaccines based on B-cell, CD4+, and CD8+ epitopes. Epitopes were selected based on allergenicity, antigenicity, and toxicity parameters. The prioritized epitopes were then combined via peptide linkers and N-terminally fused to various protein adjuvants, including PADRE, beta-defensin 3, 50S ribosomal protein L7/12, RS-09, and the cholera toxin B subunit (CTB). All vaccine constructs were computationally validated for physicochemical properties, antigenicity, allergenicity, safety, solubility, and structural stability. The three-dimensional structure of the selected construct was also predicted. Moreover, molecular docking and molecular dynamics (MD) simulations between the vaccine and the TLR-4 immune receptor demonstrated a strong and stable interaction. The vaccine construct was codon-optimized for high expression in the E. coli and was finally cloned in silico into the pET21a (+) vector. Collectively, these results could represent innovative tools for vaccine formulation against MPXV and be transformative for other infectious diseases. Full article

Marek’s disease (MD), induced by the highly contagious Marek’s disease virus (MDV), remains a significant challenge to global poultry health despite extensive vaccination efforts. This study employed integrated transcriptomic and metabolomic analyses to investigate liver responses in naturally MDV-infected Wenchang chickens during late infection stages. RNA sequencing identified 959 differentially expressed genes (DEGs) between the infected and uninfected groups. Functional enrichment analysis demonstrated that these DEGs were primarily associated with canonical pathways related to metabolism and cellular processes, including lipid, carbohydrate, and amino acid metabolism, as well as the p53 signaling pathway, cell cycle, and apoptosis. Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) detected 561 differentially expressed metabolites (DEMs), showing near-significant enrichment (p = 0.069) in phenylalanine metabolism. Integrated analysis of transcriptomics and metabolomics data highlighted that critical gene–metabolite pairs such as SGPL1-palmitaldehyde–sphinganine-1-phosphate and ME1-NADP+–malic acid potentially mediate functional crosstalk between sphingolipid metabolism and cellular redox homeostasis during viral oncogenesis. This comprehensive mapping of regulatory networks provides insights into host–virus interactions during MDV pathogenesis, offering potential applications in immunomodulation approaches, targeted therapeutic strategies, and vaccine adjuvant development. Full article

Hepatocellular carcinoma (HCC) remains a therapeutic challenge due to metabolic plasticity and drug resistance. Oncolytic viruses (OVs), such as thymidine kinase-deleted vaccinia virus (oncoVV), selectively lyse tumors while stimulating antitumor immunity, however, their metabolic interplay with cancer cells is poorly understood. Here, we engineered an oncoVV-expressing Aphrocallistes vastus lectin (oncoVV-AVL) and uncovered its unique ability to exploit the ACSS2/TFEB axis, driving metabolic competition in HCC. In vitro, oncoVV-AVL triggered cell autophagy and lipid accumulation (3.4–5.7-fold upregulation of FASN and ACC1) while suppressing glucose uptake (41–63% higher extracellular glucose and 33–34% reduced lactate). Mechanistically, oncoVV-AVL upregulated acetyl-CoA synthetase 2 (ACSS2), promoting its nuclear translocation and interaction with transcription factor EB (TFEB) to concurrently activate lipogenesis and autophagic flux. The pharmacological inhibition of ACSS2 abolished these effects, confirming its central role. In vivo, oncoVV-AVL suppressed tumor growth while inducing lipid deposition (2-fold triglyceride increase), systemic hypoglycemia (42% glucose reduction), and autophagy activation (elevated LC3B-II/I ratios). This study establishes ACSS2 as a metabolic checkpoint in OV therapy, providing a rationale for combining oncolytic virotherapy with metabolic modulators in HCC. Full article

Porcine endogenous retroviruses (PERVs) are integrated into the genome of all pigs. As they can be released as infectious virus particles capable of infecting human cells in vitro, they pose a potential risk for xenotransplantation involving pig cells or organs. To assess whether pigs produce infectious human-tropic viruses, infection assays with human cells are required. There are three main types of assays. First is the incubation of human target cells with gamma-irradiated pig cells. This method ensures that viral transmission is assessed in the absence of replicating pig cells. However, gamma irradiation may alter gene expression in pig cells, potentially affecting the results. Second is the co-culture in a double-chamber system in which pig and human cells are separated by a porous membrane, preventing direct cell-to-cell contact. While this method allows for the detection of infection by free virus particles, it does not account for infection via cell-to-cell transmission, which is a common mode of retroviral infection. And third is the co-culture of pig cells with human cells expressing a resistance gene. The resistance gene allows selective elimination of pig cells upon the addition of a selection medium. This assay enables both free virus and cell-to-cell transmission as well as complete removal of pig cells, which may not be fully achieved in the first type of assay. The third assay best simulates the conditions of in vivo xenotransplantation. However, in all cases the selection of donor and recipient cells is crucial to the experimental outcome. Results only indicate whether a specific pig cell type releases PERVs and whether a specific human cell type is susceptible to infection. A negative infection result does not necessarily reflect the in vivo situation, in which a transplanted organ consists of multiple pig cell types interacting with a diverse range of human cells within a living organism. Knowledge of these limitations is important for authorities regulating clinical applications for xenotransplantation. Full article

The H1N1 swine influenza viruses CQ91 and CQ445, isolated from pigs in China, exhibited distinct virulence in mice despite sharing similar genomic constellations. CQ91 demonstrated higher pathogenicity (MLD₅₀: 5.4 log₁₀ EID₅₀) and replication efficiency in mice compared to CQ445 (MLD₅₀: 6.6 log₁₀ EID₅₀). Through reverse genetics, we found that the attenuation of CQ445 was due to a single substitution of glutamic acid (E) with lysine (K) at position 343 in the PB2 protein. Introducing the CQ445-PB2 (343K) into CQ91 significantly reduced viral replication and pathogenicity in mice, while replacing CQ445-PB2 with CQ91-PB2 (343E) restored virulence. In vitro studies showed that the K343E mutation impaired viral replication in MDCK and A549 cells and reduced polymerase activity in minigenome assays. Mechanistically, the amino acid at position 343 in the PB2 affects the transcription stage of the viral replication process. Structural modeling indicated that the charge reversal caused by E343K altered local electrostatic interactions without major conformational changes. Phylogenetic analysis revealed that PB2-343E is highly conserved (>99.9%) in human and swine H1/H3 influenza viruses, suggesting that PB2-343E confers an adaptive advantage. This study identifies PB2-343E as a critical determinant of influenza virus pathogenicity in mammals, highlighting its role in host adaptation. Full article