Search Results (6,174)

Several studies have demonstrated that methionine supplementation in fish diets enhances immune status, inflammatory response, and resistance to bacterial infections by modulating for DNA methylation, aminopropylation, and transsulfuration pathways. However, the immunomodulatory effects of methionine in viral infections remain unexplored. This study aimed to evaluate the effect of methionine supplementation on immune modulation and resistance to the viral haemorrhagic septicaemia virus (VHSV) in rainbow trout (Oncorhynchus mykiss). Two diets were formulated and fed to juvenile rainbow trout for four weeks: a control diet (CTRL) with all nutritional requirements, including the amino acid profile required for the species, and a methionine-supplemented diet (MET), containing twice the normal requirement of DL-methionine. After feeding, fish were bath-infected with VHSV, while control fish were exposed to a virus-free bath. Samples were collected at 0 (after feeding trial), 24, 72, and 120 h post-infection for the haematological profile, humoral immune response, oxidative stress, viral load, RNAseq, and gene expression analysis. In both diets, results showed a peak in viral activity at 72 h, followed by a reduction in viral load at 120 h, indicating immune recovery. During the peak of infection, leukocytes, thrombocytes, and monocytes migrated to the infection site, while oxidative stress biomarkers (superoxide dismutase glutathione S-transferase, and glutathione redox ratio) suggested a compromised ability to manage cellular imbalance due to intense viral activity. At 120 h, immune recovery and homeostasis were observed due to an increase in the amount of nitric oxide, GSH/GSSG levels, leukocyte replacement, monocyte influx, and a reduction in the viral load. When focusing on the infection peak, gene ontology (GO) analysis showed several exclusively enriched pathways in the skin and gills of MET-fed fish, driven by the upregulation of several key genes. Genes involved in recognition/signalling, inflammatory response, and other genes with direct antiviral activity, such as TLR3, MYD88, TRAF2, NF-κB, STING, IRF3, -7, VIG1, caspases, cathepsins, and TNF, were observed. Notably, VIG1 (viperin), a key antiviral protein, was significantly upregulated in gills, confirming the modulatory role of methionine in inducing its transcription. Viperin, which harbours an S-adenosyl-L-methionine (SAM) radical domain, is directly related to methionine biosynthesis and plays a critical role in the innate immune response to VHSV infection in rainbow trout. In summary, this study suggests that dietary methionine supplementation can enhance a more robust fish immune response to viral infections, with viperin as a crucial mediator. The improved antiviral readiness observed in MET-fed fish underscores the potential of targeted nutritional adjustments to sustain fish health and welfare in aquaculture. Full article

The development of eco-friendly antimicrobial materials is essential for addressing antibiotic resistance, while reducing environmental impact. In this study, bio-derived anionic and cationic cellulose nanofibers (a-CNF and c-CNF) were employed as templating matrices for the in situ hydrothermal synthesis of cellulose/ZnO nanohybrids. Physicochemical characterization confirmed efficient cellulose functionalization and high-quality nanofibrillation, as well as the formation of uniformly dispersed ZnO nanoparticles (≈10–20 nm) strongly integrated within the cellulose network. The ZnO content was 30 and 20 wt. % for a-CNF/ZnO and c-CNF/ZnO, respectively. Antibacterial evaluation against Escherichia coli and Staphylococcus aureus revealed enhanced activity for both hybrids, with c-CNF/ZnO displaying the lowest MIC/MBC values (50/100 μg/mL). Antiviral assays revealed complete feline calicivirus inactivation at 100 μg/mL for c-CNF/ZnO, while moderate activity was observed against bovine coronavirus, highlighting the role of surface charge. Cytotoxicity assays on mammalian cells demonstrated high biocompatibility at antimicrobial concentrations. Life cycle assessment showed that c-CNF/ZnO exhibits a lower overall environmental burden than a-CNF/ZnO, with electricity demand being the main contributor, indicating clear opportunities for further reductions through process optimization and scale-up. Overall, these results demonstrate that CNF/ZnO nanohybrids effectively combine renewable biopolymers with ZnO antimicrobial functionality, offering a sustainable and safe platform for biomedical and environmental applications. Full article

The emergence of SARS-CoV-2, the etiological agent of COVID-19, has resulted in widespread global infection and millions of deaths. Viral entry is initiated by the interaction between the viral spike (S) protein and the host cell receptor ACE2, followed by TMPRSS2-mediated proteolytic activation that facilitates membrane fusion. Bitter melon (Momordica charantia L., MC), a traditional medicinal and edible plant widely used in tropical Asia, possesses notable anti-inflammatory, antioxidant, antitumor, and hypoglycemic properties. In this study, the ethanol extract of bitter melon (EMC) markedly downregulated ACE2 and TMPRSS2 expression in both in vitro and in vivo models without inducing cytotoxicity. Furthermore, phytochemicals isolated from EMC—including p-coumaric acid, rutin, and quercetin—exhibited comparable inhibitory effects. These results indicate that EMC and its bioactive constituents may interfere with SARS-CoV-2 entry by modulating the ACE2/TMPRSS2 axis, highlighting their potential as natural adjuncts for COVID-19 prevention or management. Full article

Ionic liquids (ILs) have emerged as multifunctional compounds with low volatility, high thermal stability, and tunable solvation capabilities, making them highly promising for biomedical applications. First explored in the late 1990s and early 2000s for enhancing the thermal stability of enzymes, antimicrobial agents, and controlled release systems, ILs have since gained significant attention in drug delivery, antimicrobial treatments, medical imaging, and biosensing. This review examines the diverse functions of ILs in contemporary therapeutics and diagnostics, highlighting their transformative capabilities in improving drug solubility, bioavailability, transdermal permeability, and pathogen inactivation. In drug delivery, ILs improve solubility of bioactive compounds, with several IL formulations achieving substantial solubility enhancements for poorly soluble drugs. Bio-ILs, in particular, show promise in enhancing drug delivery systems, such as improving transdermal permeability. ILs also exhibit significant antimicrobial and antiviral activity, offering new avenues for combating resistant pathogens. Despite their broad potential, challenges such as cytotoxicity, long-term metabolic effects, and the stability of ILs in physiological conditions persist. While much research has focused on their physicochemical properties, biological activity and in vivo studies are still underexplored. The future directions for ILs in biomedical applications include the development of bioengineered ILs and hybrid ILs, combining functional components like nanoparticles and polymers to create multifunctional materials. These ILs, derived from renewable resources, show great promise in personalized medicine and clinical applications. Further research is necessary to evaluate their pharmacokinetics, biodistribution, and long-term safety to fully realize their biomedical potential. This study emphasizes the potential of ILs to transform therapeutic and diagnostic technologies by highlighting present shortcomings and offering pathways for clinical translation, while also debating the need for continuous research to fully utilize their biomedical capabilities. Full article

Background: The interaction between helminth and viral infections has important implications for understanding viral disease outcomes and vaccine efficacy in helminth-endemic regions. We previously demonstrated that helminth seropositivity is associated with reduced Th1/Th17 cytokine levels and reduced COVID-19 severity; however, the underlying immunological mechanisms remain unclear. This study further investigated these mechanisms by assessing how helminth antigens influence SARS-CoV-2-induced T-cell responses in individuals infected with filarial parasites in vitro. Methods: Peripheral blood mononuclear cells (PBMCs) from 43 participants, including Onchocerca volvulus-infected individuals, filarial lymphedema patients, and non-endemic controls, were stimulated in vitro with SARS-CoV-2 peptides and Ascaris lumbricoides antigens. Results: Fluorescence-activated cell sorting analysis showed a significant reduction in SARS-CoV-2-induced CD154 expression on CD4⁺ T cells but an increase on CD8⁺ T cells in O. volvulus-infected participants (p < 0.0001). A. lumbricoides antigens alone did not induce significant T-cell activation in O. volvulus-infected individuals. However, SARS-CoV-2 peptides strongly activated CD4⁺CD154⁺ T cells response (p = 0.0074), but co-stimulation with A. lumbricoides antigens markedly reduced CD3⁺ and CD4⁺CD154⁺ T-cell expression frequencies (p = 0.0329 and p = 0.0452). A. lumbricoides-specific IgG correlated inversely with SARS-CoV-2-induced CD4⁺CD154⁺ expression (r = −0.6025, p = 0.0049), whereas SARS-CoV-2-specific IgG was positively associated with CD4⁺CD154⁺ and CD8⁺CD154⁺ T-cell responses (β = 0.532, p = 0.016 and β = 0.509, p = 0.022). Conclusion: These findings demonstrate that helminth antigens modulate functional SARS-CoV-2-induced T-cell responses, offering a potential mechanism through which helminth co-infections shape antiviral immunity, vaccine efficacy, and clinical disease outcomes. Full article

Interferons (IFNs) are essential mediators of the innate immune response to viral infections. Among the type III IFNs, the role of IFN-λ4 in respiratory viral infections remains largely understudied. Respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) are clinically significant pneumoviruses that elicit divergent IFN responses in epithelial cells. Here, we investigate the virus-specific induction and antiviral activity of IFN-λ4 by HMPV and RSV infections. We demonstrate that RSV induces a limited expression of IFN-λ4, which is regulated by the expression of the NS1 protein. Furthermore, RSV and HMPV rely primarily on RIG-I for IFN-λ4 induction. Finally, we show that IFN-λ4 exerts antiviral activity against both viruses, with RSV displaying greater sensitivity. These findings highlight the antiviral role of IFN-λ4 to clinically relevant respiratory viruses. Full article

Fucoidan, a complex sulfated polysaccharide derived from marine brown seaweeds, exhibits broad biological activities, including anticoagulant, antitumor, antiviral, anti-inflammatory and lipid-lowering effects. Fucoidan confers neuroprotection in animal models of a broad spectrum of brain disorders such as Parkinson’s disease (PD) and depression. However, the effect of fucoidan on gut-derived neuroinflammation and associated behavioral changes has been scarcely investigated. In comparison to fucoidan from other brown seaweeds, that from Fucus vesiculosus exhibited a better neuroprotective effect in vivo and more potent radical scavenging activity in vitro. Fucoidan from Laminaria japonica ameliorates behavioral disorders related to acute ulcerative colitis (UC) in aged mice. It is of interest to assess the effects of fucoidan administration on intestinal and brain inflammation in the acute colitis mouse model. Fucoidan treatment ameliorated DSS-induced intestinal pathology, reduced the inflammatory mediator expression in the gut and brain, and activated intestinal macrophages and cortical microglia in the UC mice. It also protected the intestinal mucosal barrier and blood–brain barrier as well as prevented neuronal damage, while alleviating anxiety-like behavior in UC mice. These results suggest fucoidan supplementation may help prevent brain disorders, such as depression and PD, potentially involving gut–brain axis-related mechanisms, as fucoidan suppresses gut-derived neuroinflammation. Full article

Dendritic cells (DCs) are essential for antiviral immunity but are also susceptible to HIV-1 infection. Although sensing and restriction pathways in DCs are well described, the mechanisms underlying latent infection and its functional consequences remain unclear. In this study, we performed transcriptomic profiling of monocyte-derived DCs harboring transcriptionally active (Active-HIV) or latent HIV-1 (Latent-HIV) proviruses using a dual-reporter virus. Gene set enrichment analysis revealed suppression of metabolic and stress-modulatory programs in Active-HIV compared to unexposed DCs. In contrast, Latent-HIV showed broad downregulation of pathways, including interferon and innate responses and metabolic programs, indicating a hyporesponsive and dampened antiviral state despite the absence of differentially expressed genes (DEGs). DEG analysis of Active-HIV versus Latent-HIV showed that active transcription associates with cellular stress, cytoskeletal remodeling, and RNA processing. Functional analyses further demonstrated the activation of RNA processes, the suppression of antigen-presentation pathways, and altered membrane and cytoskeletal signaling in Active-HIV. These pathways suggest that transcriptionally active HIV-1 is linked to cellular programs supporting replication, coinciding with a metabolically strained yet immunologically engaged state that may impair antigen presentation. Conversely, latently infected DCs display a hyporesponsive state consistent with proviral silencing. This dichotomy reveals distinct mechanisms of DC dysfunction that may facilitate HIV-1 persistence and immune evasion. Full article

Requirements for novel effective antiviral agents against SARS-CoV-2 emphasizes the importance of robust in vitro screening platforms. We developed a test system based on spike-pseudotyped lentiviruses, carrying either luc+ or EGFP reporter genes as a payload, and a human non-small cell lung carcinoma (NSCLC) cell line, overexpressing ACE2 (H1299-hACE2). The cell origin makes our system resemble lung epithelium infection. Transmission electron microscopy confirmed that the spike glycoproteins on the pseudotyped lentiviral particles resemble native SARS-CoV-2 spike glycoproteins, thus validating their use in inhibitor screening. H1299-hACE2 cells showed significantly higher infection rate (p < 0.005) with spike-pseudotyped lentiviruses compared to parental H1299 cells, as determined by luciferase and fluorescence assays. The susceptibility of the stable H1299-hACE2 cell line to a broad panel of SARS-CoV-2 variants (Wuhan, Beta, Delta, Omicron) was assessed here for the first time in a unified experimental setting. Infection of H1299-hACE2 cells with SARS-CoV-2 induced cell fusion and syncytium formation with subsequent cell death. The developed pseudovirus-based assay was further used for assessment of the antiviral properties of derivatives of 1,7,7-trimethyl-[2.2.1]-bicycloheptane-potential spike protein inhibitors, which possess moderate activity against lentiviral particles. The H1299-hACE2/spike-pseudotyped lentivirus assay is, therefore, a reliable, high-efficiency platform for screening spike-mediated entry inhibitors. The cell line obtained during the development of the platform can be used to isolate and study new variants of SARS-CoV-2. Full article

Tobacco mosaic virus (TMV) threatens crop yield and quality, while chemical antivirals offer limited efficacy and potential environmental hazards. Marine fungal polysaccharides are promising eco-friendly alternatives due to their biocompatibility and biodegradability. Here, extracellular polysaccharides (EPSs) from the deep-sea fungus Beauveria bassiana T2-2 was isolated, characterized, and produced under optimized conditions (28 °C, 200 rpm, 9 days, pH 8, inoculum 4%) using an L9 (3⁴) orthogonal medium, yielding 3.42 g/L, which is a 48% increase over unoptimized culture. EPSs were glucose-rich, with a molecular weight of 3.56 × 10⁴ Da, containing 90.05% total sugar, 0.28% protein, 1.15% uronic acid, and 1.18% sulfate. In a Nicotiana benthamiana–TMV model, EPSs alleviated viral symptoms, maintained chlorophyll content, enhanced antioxidant enzymes (SOD, POD, CAT), reduced malondialdehyde, and upregulated defense genes in SA, ET, ROS, and phenylpropanoid pathways. EPSs, alone or combined with Ribavirin, activated multi-pathway antiviral immunity, highlighting its potential as a sustainable plant-protective agent. Full article

Respiratory syncytial virus (RSV) remains a leading cause of lower respiratory tract infections (LRTIs) and infant mortality worldwide. Despite recent advances in prophylactic interventions, effective therapeutics for active RSV infection are still lacking. Small molecule non-nucleoside inhibitors (NNIs) targeting the RSV L protein, particularly its polyribonucleotidyltransferase (PRNTase) domain, represent a promising antiviral strategy. Here, we evaluate the genetic variability of the PRNTase domain and the binding pocket of two NNIs, MRK-1 and MRK-2, to assess the potential for preexisting resistance. A comprehensive analysis of 28,140 RSV L protein sequences from NCBI Virus and GISAID EpiRSV databases revealed low overall variability within the PRNTase domain and near-complete conservation of the MRK-1/2 binding pocket. Resistance-associated mutations identified through in vitro dose-escalation studies localized to this pocket but were absent in global sequence datasets. These findings support the PRNTase domain as a genetically stable and viable target for NNI-based RSV therapeutics and suggest a low likelihood of preexisting resistance among circulating strains. Full article

Signal transducer and activator of transcription 2 (STAT2) is a key component of the type I interferon (IFN-I/III) signaling pathway, which is pivotal in host defense against cancer and viral infections and in shaping immune responses. Building on our previously reported conditional Stat2 knockout (KO) mouse, we expand its utility by validating additional tissue-specific models and exploring novel functional contexts. Mice carrying loxP-flanked Stat2 alleles were crossed with CMV-Cre, Cdx2-Cre or CD11c-Cre mice. Deletion of STAT2 was validated by PCR genotyping and western blotting in the relevant tissues. To confirm defective IFN-I signaling with STAT2 deletion, IFN-β stimulation of splenocytes from CMV-Cre Stat2 KO mice showed a lack of induction of canonical IFN-I target genes, confirming functional disruption of the pathway. In vivo, global Stat2 deletion significantly impaired the antitumor efficacy of IFN-β treatment. Similarly, lung fibroblasts isolated from globally deleted Stat2 KO mice showed defective antiviral responses to IFN-β. Tissue-specific Cre models demonstrated selective ablation of STAT2 in target compartments without affecting its expression in non-target tissues. Together, these studies expand our published conditional Stat2 KO findings and highlight the value of this model as a versatile platform for dissecting STAT2-dependent signaling pathways in a tissue- and disease-specific manner. Full article

White Spot Syndrome Virus (WSSV) remains one of the most devastating pathogens in global shrimp aquaculture, causing massive economic losses annually. This study employed comparative transcriptomics to elucidate the molecular basis of the differential resistance to WSSV between the highly susceptible Pacific white shrimp (Litopenaeus vannamei) and the remarkably resistant oriental river prawn (Macrobrachium nipponense). Our analysis of gill, hepatopancreas, and muscle tissues at 24 h post-infection revealed fundamentally distinct defense strategies. The resistant M. nipponense employs a unique “proactive homeostatic reinforcement” strategy, characterized by significant enrichment of pathways central to cellular homeostasis, including signal transduction, cellular processes, and transport/catabolism. This approach, supported by coordinated up-regulation of heat shock proteins and structural genes, enables effective viral control without triggering excessive immune activation. In contrast, susceptible L. vannamei displays either widespread metabolic dysregulation leading to systemic collapse in moribund individuals or dependency on specific immune pathways (Toll-like receptor signaling and apoptosis) in survivors. Through comparative KEGG analysis, we identified heat shock protein 70 kDa (HSP70, K03283) as a key conserved gene and functionally validated its critical role in antiviral defense using RNA interference. Knockdown of HSP70 in M. nipponense significantly increased cumulative mortality and viral load, confirming its essential protective function. These findings provide novel insights into crustacean antiviral immunity and identify promising genetic targets for breeding WSSV-resistant shrimp strains, offering sustainable solutions for disease management in aquaculture. Full article

Mammarenaviruses (MaAv) cause persistent infection in their natural rodent hosts across the world and, via zoonotic events, can cause severe disease in humans. Thus, the MaAv Lassa virus (LASV) in Western Africa and the Junin virus (JUNV) in the Argentinean Pampas cause hemorrhagic fever diseases with significant case fatality rates in their endemic regions. In addition, the globally distributed MaAv lymphocytic choriomeningitis virus (LCMV) is an underrecognized human pathogen of clinical significance capable of causing devastating infections in neonates and immunocompromised individuals. Despite their impact on human health, there are currently no FDA-approved vaccines or specific antiviral treatments for MaAv infections. Existing anti-MaAv therapies are limited to the off-label use of ribavirin, whose efficacy remains controversial; hence, the development of novel therapeutics to combat human pathogenic MaAv is vital. We employed a high-throughput cell-based infection assay to screen the Pandemic Response Box, a collection of 400 diverse compounds with established antimicrobial activity, for MaAv inhibitors. We identified Ro-24-7429, an antagonist of the HIV-1 Tat protein and RUNX family transcription factor 1 inhibitor; WO 2006118607 A2, a dihydroorotate dehydrogenase inhibitor; and verdinexor, a novel selective inhibitor of nuclear export (SINE) targeting the XPO1/CRM1, as potent anti-MaAv compounds. Consistent with their distinct validated targets, verdinexor and WO 2006118607 A2 exhibited very strong synergistic antiviral activity when used in combination therapy. Our findings pave the way for the development of verdinexor as a potent host-directed antiviral against MaAv, which could be integrated into the development of combination therapy with direct- or host-acting antivirals to combat human pathogenic MaAv. Full article

Necroptosis is an antiviral form of programmed cell death modulated by proteins that interact via RIP Homotypic Interaction Motifs (RHIMs). The result of the signaling pathways depends on which RHIM-containing proteins are involved: although both host and viral proteins contain RHIMs, virally encoded RHIM proteins, such as murine cytomegalovirus (MCMV)-encoded viral inhibitor of RIP activation (vIRA) serve to prevent cell death. Although every RHIM contains the same core four-amino-acid pattern, there are variations in individual sequences that we hypothesized would determine the differential outcomes in necroptotic signaling. As such, we replaced the RHIM in vIRA with the RHIMs from other proteins involved in the signaling cascade (RIPK1, RIPK3, ZBP1, ICP6) to assess the effect on necroptosis during MCMV infection. Although these RHIM-swap vIRA constructs remained able to bind to RIPK3, in the context of MCMV infection, they lost the ability to prevent necroptosis. These results are consistent with other studies that demonstrate that RHIM-containing proteins form amyloid fibrils unique to the proteins interfacing. Our results provide biological context for the growing model that the outcome of RHIM-based signaling is influenced by the specific amyloid fibril structures that are driven by the unique amino-acid sequences of each RHIM present. Full article