Search Results (834)

Ubiquitination is a key post-translational modification regulating cellular signaling and innate immunity, and its reversal by deubiquitinases (DUBs) represents a critical mechanism exploited by pathogens for immune evasion. While ovarian tumor (OTU) domain-containing DUBs are well characterized in viral systems, their roles in fungal pathogens remain largely unexplored. In this study, we investigated two putative OTU domain-containing proteins derived from the plant pathogenic fungi Melampsora larici-populina (MlpOTU, EGG09943.1) and Taphrina deformans (TdOTU, CCG84064.1). Recombinant MlpOTU and TdOTU proteins were successfully expressed and purified from E. coli and exhibited high solubility and proper folding. Functional analyses in HEK293T cells demonstrated that both proteins significantly reduce global ubiquitination levels, confirming their deubiquitinase activity in vivo. Despite this shared enzymatic function, the two proteins displayed markedly distinct effects on host immune gene expression. MlpOTU selectively suppressed key antiviral effectors, most notably MX1, suggesting a targeted immune evasion strategy. In contrast, TdOTU induced robust upregulation of multiple immune-related genes, including type I interferons, indicating a divergent role. Neither MlpOTU nor TdOTU triggered robust apoptosis, supporting their role as modulators of host signaling rather than cytotoxic effectors. Collectively, these findings provide the first functional evidence that fungal OTU domain-containing proteins act as active deubiquitinases and reveal distinct strategies by which plant pathogens may manipulate host immune responses. This study establishes fungal OTU domains as promising targets for antifungal intervention and broadens our understanding of cross-kingdom evasion mechanisms. Full article

Porcine reproductive and respiratory syndrome virus (PRRSV) remains a major challenge to swine production worldwide. Current vaccines have limited efficacy against genetically diverse PRRSV strains. Therefore, strategies with alternative modes of action—such as antiviral approaches that target conserved virus–host interactions, including viral attachment and entry, rather than relying solely on adaptive immune responses—are needed. We first evaluated the in vitro effect of griffithsin (GRFT), a high-mannose-binding lectin, in the monkey kidney cell line MARC-145. Cells were pre-treated with GRFT (50–200 µg/mL) prior to PRRSV infection, after which cell morphology and viral RNA replication (measured by RT-qPCR) were assessed. Pre-treatment with 100–200 µg/mL GRFT, followed by PRRSV inoculation at a multiplicity of infection of 1 or 10, reduced viral replication in MARC145 cells in a dose-dependent manner, achieving almost 100% inhibition of ORF5 and ORF7 RNA compared with untreated controls (p < 0.0001). We next investigated the in vivo effects of intranasal GRFT administration (7.5 or 15 mg/day) in pigs (n = 56). Pigs treated with 15 mg/day GRFT exhibited significantly reduced (p < 0.05) viremia 2, 4 and 7 days post-challenge, compared with untreated, challenged, and controls (log₁₀ 8.1 ± 0.2 vs. 9.0 ± 0.25, 8.2 ± 0.1 vs. 9.1 ± 0.2, and 8.9 ± 0.2 vs. 9.3 ± 0.2, respectively), along with earlier resolution of fever and a trend toward increased average daily gain over 42 days (p < 0.1). These findings are the first report of GRFT efficacy in pigs and support its potential as an antiviral strategy against PRRSV, alongside existing interventions. Full article

Human endogenous retroviruses (HERVs) are potential driving forces of the pathophysiology of Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), linking post-infectious immune dysfunction to chronic inflammation and immune and neurocognitive dysfunction that are hallmark features of ME/CFS. Accumulating evidence from related autoimmune diseases and cancers has shown that reactivated HERVs can contribute to disease pathogenesis by amplifying immune activation through viral protein-mediated innate sensing, long terminal repeat (LTR)-driven transcription, and disrupting epigenetic silencing. HERV signatures are therefore promising biomarkers for diagnosis, patient stratification for drug-repurposing trials, and therapy monitoring. Accumulating evidence suggests a possible correlation between HERV expression and ME/CFS symptom severity, alterations in immune phenotypes, function and inflammatory gene networks. Importantly, locus-specific HERV profiling is a promising approach for distinguishing ME/CFS from overlapping or co-morbid conditions and healthy controls. Furthermore, HERV-targeted antibodies, immune modulators, epigenetic and antiviral interventions offer promise as concomitant therapeutic strategies for ME/CFS. Additional research incorporating viromics and other-omics validation, functional assays, and HERV-stratified clinical trials is now needed to realise this potential and to transform ME/CFS from a symptom-based syndrome into a mechanism-driven, treatable condition. Full article

Zika virus (ZIKV) is an emerging flavivirus associated with congenital malformations and ocular complications, representing a significant public health concern. Retinal pigment epithelium (RPE) cells play a key role in maintaining retinal integrity and represent a primary target of ZIKV infection, making them a relevant model for studying host–virus interactions. In this study, we evaluated the antiviral activity of fat- and water-soluble vitamins against ZIKV in hTERT RPE-1 (hRPE1) cells. Particularly, vitamin A was identified as the compound that most effectively inhibited viral replication. Molecular dynamics simulations focusing on the PAS-B domain of the aryl hydrocarbon receptor (AHR) revealed a high affinity of vitamin A for the receptor. In hRPE1 cells, vitamin A treatment reduced viral RNA levels and decreased CYP1A1, TDO, and AHR mRNA expression. In parallel, IFNB1 expression increased, consistent with the involvement of type I interferon (IFN-I), as no antiviral effect was observed in IFN-I-deficient Vero cells. These findings suggest that vitamin A restricts ZIKV replication through host antiviral responses, potentially involving modulation of AHR-associated signaling. The combination of vitamin A and the well-known polyphenol resveratrol further enhanced antiviral activity, showing predominantly additive effects. Together, these results support the potential use of both bioactive compounds as a combined therapeutic strategy. Full article

This review investigates biomaterial-based strategies for improved treatment of MPXV. We focus on emerging synthetic biomedical approaches to combating the virus. These include peptide nucleic acids, CRISPR-based systems, and small-molecule therapeutics. These methods work by targeting and blocking viral proteins and enzymes. Such synthetic platforms may help reduce viral transmission and minimize side effects. They also offer potential solutions to challenges such as viral resistance in humans. In addition, biomaterials contribute to the development of more stable and effective vaccines. Combining these biomaterials with mRNA technology provides a promising framework for future vaccine development. Overall, this review underscores biomaterial-driven antiviral systems as a major frontier in translational medicine with profound implications for global health and pandemic awareness. Full article

RNA viruses encode multiple layers of regulatory information within their genomes, extending beyond their protein-coding sequences. Through local secondary structures and long-range RNA–RNA interactions, viral RNAs control essential steps of the viral life cycle, including translation, replication, genome cyclization, packaging, and evasion of host defenses. Over the last two decades, chemical probing approaches—particularly Selective 2′-Hydroxyl Acylation analyzed by a primer extension (SHAPE) and its high-throughput derivatives—have transformed our ability to investigate these structures at a single nucleotide resolution and on a genome-wide scale. These technologies have revealed that viral genomes are highly structured and contain numerous functional RNA elements within untranslated regions as well as coding sequences. In this review, we summarize the main experimental strategies used to profile viral RNA architecture, with a focus on SHAPE-based methodologies and complementary approaches. We then discuss the major classes of functional RNA structures identified across diverse viral families, focusing on elements involved in translation and replication, such as internal ribosome entry sites (IRES) and cyclization elements, as well as other functional structures, including XRN1-resistant and frameshifting elements. Finally, we examine how structure-guided analyses are opening new avenues for antiviral intervention, including antisense oligonucleotides, small molecules, and RNA-degrading chimeras. Together, these advances highlight the viral RNA structure as both a key determinant of virus biology and a promising target for therapeutic innovation. Full article

Functional antibody-dependent enhancement (ADE) represents a fundamental and context-dependent characteristic of antiviral antibody responses, reflecting the dual capacity of antibodies to mediate both the neutralization and Fc receptor-dependent enhancement of infection. In flavivirus research, this duality complicates the interpretation of conventional serological metrics and limits the reliability of single-parameter correlates of immunity, particularly in populations with complex exposure histories. Over the past decade, functional ADE assays have evolved from specialized mechanistic tools into integrated immune assessment platforms supporting translational immunology, vaccine evaluation, and population-level immune surveillance. These platforms incorporate Fcγ receptor-relevant target cell systems, standardized viral inputs, dilution series-based profiling, quantitative enhancement metrics, and structured quality control frameworks to enable reproducible, comparable, and context-aware functional measurements across cohorts and laboratories. A central concept emerging from these developments is that ADE reflects a dynamic functional immune state rather than an intrinsic property of antibodies or a direct indicator of pathological risk. Accordingly, functional ADE platforms support the contextual interpretation of antibody activity across physiologically relevant conditions, facilitating discrimination between transient functional enhancement and clinically meaningful immunological risk. By integrating functional ADE metrics with serological, cellular, and epidemiological data, these platforms provide a structured framework for interpreting immune profiles in vaccine evaluation, booster strategy design, and population-level risk stratification. This review synthesizes the development, standardization, and global dissemination of functional ADE platforms and discusses key principles governing biological relevance, analytical robustness, and inter-site transferability. Emerging directions integrating functional ADE profiling with systems immunology, immunogenomics, and computational modeling are highlighted as pathways toward predictive, decision-support-oriented frameworks. By positioning ADE platforms as immune assessment infrastructures rather than isolated assays, this review underscores their value for mechanistic inquiry, translational interpretation, and preparedness-oriented responses to emerging viral threats in the absence of definitive correlates of protection. Full article

Dengue virus (DENV) and SARS-CoV-2 are emerging viral pathogens that share overlapping clinical features, including fever, fatigue, and respiratory symptoms, complicating differential diagnosis in endemic regions. Their co-circulation has increased the risk of co-infections, which may result in unpredictable disease progression, increased morbidity, and mortality. This overlap presents a significant challenge in managing outbreaks, as both viruses pose a major public health threat. Vaccines and direct-acting antivirals may be rendered ineffective by viral mutations, making it difficult to address evolving strains. Host-directed antivirals offer a promising alternative, potentially maintaining efficacy against a multitude of variants. Both DENV and SARS-CoV-2 rely on host proteases for viral maturation and entry, with furin playing a crucial role in viral glycoprotein cleavage. In DENV, furin cleaves the prM protein, facilitating virion maturation, while in SARS-CoV-2, the polybasic furin cleavage site in the spike protein enhances viral entry. This makes furin a compelling pan-viral target, where inhibiting furin could reduce viral fitness without relying on viral mutations. This review highlights the therapeutic rationale for targeting furin and discusses luteolin, a furin inhibitor showing antiviral activity against both viruses. Furin-targeted therapies may offer a durable antiviral strategy effective across DENV serotypes, SARS-CoV-2 variants, and co-infection settings. Full article

Antimicrobial peptides (AMPs) are natural bioactive peptides produced by all organisms—from plants to insects, microbes and animals—and constitute a first line of defense. As they exhibit a broad spectrum of activity (antibacterial, antiviral, antifungal, antiparasitic, anticancer), strong efforts are being made to integrate AMPs into clinical use. AMPs are also being investigated as anticancer agents to overcome the side effects and/or resistance associated with current chemotherapies. In this context, we identified the natural AMP chionodracine from a new biological source: an Antarctic fish. Starting from the fragmentation of a chionodracine mutant peptide, a rational modular design approach was applied to develop three very short peptides (Pep-A, Pep-B and Pep-C), which were further modified with an N-terminal myristic acid lipid tail. The anticancer activity of the three N-myristoylated short peptides (Myr-A, Myr-B and Myr-C) was explored against the human cervical cancer HeLa cell line. The rationale behind this study is based on the previously reported antifungal activity of these myr peptides and on their ability to interact selectively with biological membrane-mimicking synthetic phospholipids without being particularly hemolytic or cytotoxic towards normal cells. We first demonstrated that myr peptides had cytotoxic activity against HeLa cells (IC₅₀ from 32 to 47 μM) but spared healthy primary human fibroblasts, whereas the corresponding non-myr peptides failed to kill cancer cells. The peptide with no hemolytic activity and a low IC₅₀, labeled Myr-B, was selected for subsequent analyses. Lactate dehydrogenase (LDH) assay and scanning electron microscopy (SEM) analysis revealed membrane damage and predominantly necrotic cell death in HeLa cells exposed to IC₅₀ doses of the Myr-B peptide, compared with cells treated with Pep-B. To thoroughly investigate the molecular effects of Myr-B in HeLa cells, we employed high-resolution label-free shotgun quantitative proteomics coupled with bioinformatics. Our results showed that exposing HeLa cells to Myr-B led to the under-expression of proteins belonging to the “apoptosis- and splicing-associated protein complex”, potentially influencing the alternative splicing process and consequently leading to a possible susceptibility to programmed cell death. These findings indicate that modifying natural AMPs may be a promising strategy for developing selective anticancer drugs and pinpoint Myr-B as an interesting target for future studies. Full article

In recent years, nanotechnology has made remarkable progress in the fight against infectious diseases. However, the development of safe and effective antiviral drugs remains a challenge, as viruses rely on host cells for replication. Plant-derived, environmentally friendly nanoparticles have gained significant attention due to their low toxicity, which enables them to target viruses without damaging host cells. In this study, we describe the synthesis of silver nanoparticles (AgNPs) using Arctostaphylos uva-ursi leaf extract and explore their potential antiviral activity. The uva-ursi AgNPs were initially characterized using nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). We then optimized two different gellan gum/alginate film formulations (1.6:0.4 and 1.2:0.8) as delivery matrices for the AgNPs and assessed Ag⁺ skin permeation using a Franz diffusion cell system. The antiviral potential of the uva-ursi AgNPs—both alone and incorporated into the films—was tested against herpes simplex virus type 1 (HSV-1). Our findings indicate that uva-ursi AgNPs may directly interact with the viral envelope, disrupting the lipid membrane and/or interfering with viral surface proteins. Overall, green-synthesized uva-ursi AgNPs may represent a natural, cost-effective, and safe alternative strategy for managing herpetic infections. Full article

The chloroplast, a key organelle for plant immunity, is frequently targeted by viral proteins to suppress host defense. Here, we demonstrate that NSvc4, the movement protein of rice stripe virus (Tenuivirus oryzaclavatae; genus Tenuivirus), functions as a chloroplast-localized virulence effector. We show that NSvc4 enters chloroplasts and directly associates with NbPsbQ, a subunit of the oxygen-evolving complex (OEC) of Photosystem II. This interaction competitively disrupts the binding of NbPsbQ to its native partners NbPsbO and NbPsbP, thereby dampening the accumulation of chloroplast-derived reactive oxygen species (cROS) and attenuating pathogen-triggered immune signaling. Genetic knockout of NbPsbQ enhanced plant susceptibility to RSV, confirming its role as a positive regulator of antiviral defense. Our study uncovers a distinct strategy whereby a viral movement protein inhibits chloroplast-mediated immunity by targeting extrinsic subunits of the OEC. These findings expand the functional scope of viral movement proteins and highlight the OEC as a critical battleground in plant–virus interactions. Full article

The m⁶A RNA methylation pathway plays a critical role in host antiviral defense. Host cells employ m⁶A readers such as YTHDF2 to regulate viral RNA fate through diverse mechanisms, including degradation, translational control, and immune recognition. However, we found that YTHDF2 is essential for SARS-CoV-2 replication, suggesting that a virus may exploit this host machinery to its advantage. Through integrative RNA-proteome analysis, we identified the SARS-CoV-2 nucleocapsid (N) transcript as the most heavily m⁶A-modified viral transcript and a direct interactor of YTHDF2. The N protein forms a complex with YTHDF2 in the cytoplasm and redirects this host RNA decay machinery toward host antiviral transcripts. N suppresses ISG15, IFIT1, MX1 and pro-inflammatory cytokines in a largely YTHDF2-dependent manner, an effect that is lost in YTHDF2-knockout cells. These findings reveal a viral immune evasion strategy wherein a viral protein actively hijacks an m⁶A reader to silence antiviral gene expression, establishing the N-YTHDF2 axis as a therapeutic target against SARS-CoV-2 and other coronaviruses. Full article

Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) represent fundamental cellular adaptive mechanisms that maintain protein homeostasis and metabolic balance. Many RNA viruses, particularly flaviviruses such as dengue virus (DENV), Zika virus (ZIKV), West Nile virus (WNV), yellow fever virus (YFV), and Japanese encephalitis virus (JEV), extensively remodel the ER to establish replication compartments and assemble progeny virions. This massive reorganization disrupts ER homeostasis, leading to UPR activation. Emerging evidence reveals that flaviviruses not only trigger but also manipulate the three UPR branches—PERK, IRE1, and ATF6—to optimize viral translation, replication, and egress. In parallel, flavivirus infection profoundly alters host lipid metabolism and promotes dynamic changes in lipid droplets (LDs), key organelles that mediate lipid storage and serve as scaffolds for viral replication and assembly. The UPR intimately connects to LD biogenesis through transcriptional and translational programs mediated by XBP1, ATF4, and ATF6, thereby coupling ER stress responses to lipid remodeling and energy homeostasis. This intricate crosstalk between UPR and LDs creates a metabolic and structural niche favorable for viral replication but detrimental to host cell integrity. This review provides a comprehensive analysis of the molecular mechanisms by which flaviviruses exploit ER stress and the UPR to reprogram lipid metabolism and LD dynamics. We highlight the dual role of UPR signaling in promoting adaptive lipid synthesis and initiating cell death under prolonged stress, discuss recent insights into ER–LD interactions during flavivirus infection, and explore therapeutic opportunities targeting UPR–lipid metabolic pathways as broad-spectrum antiviral strategies. Understanding this interconnected network will advance our knowledge of viral pathogenesis and identify new avenues for host-directed antiviral intervention. Full article

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest malignancies, characterized by early metastasis, dense desmoplastic stroma and a profoundly immunosuppressive, lymphocyte-depleted tumor microenvironment that severely limits the efficacy of current systemic and immunotherapeutic approaches. Oncolytic viruses (OVs), which selectively replicate in and lyse malignant cells while activating antitumor immunity, have emerged as attractive candidates to convert this “cold” tumor into a more inflamed and therapeutically responsive disease. In this review, we summarize clinical evidence on the main OV platforms evaluated in PDAC, including adenovirus, herpes simplex virus, vaccinia virus, parvovirus and reovirus, with a focus on clinical trials. Across these classes of viruses, intratumoral administration has consistently proven feasible and generally well tolerated, with frequent evidence of viral replication, microenvironmental remodeling and immune activation, but only modest and often transient antitumor responses in small, early-phase cohorts. We then discuss key biological and translational challenges that currently limit OV impact in PDAC, such as systemic delivery in the context of pre-existing antiviral immunity and rapid clearance, penetration through the fibrotic stroma, and rational selection of encoded transgenes to reshape myeloid cell-driven, pro-tumoral inflammation and enhance T-cell recruitment. Finally, we outline future directions for the field, including carrier-cell–based systemic delivery, stroma-targeting or cytokine-armed constructs, and combinatorial strategies with chemotherapy and immune checkpoint blockade, arguing that design refinement, innovative combinations and mechanism-driven trial designs will be essential to unlock the full therapeutic potential of oncolytic virotherapy in PDAC. Full article

Nipah virus (NiV) is a highly pathogenic zoonotic paramyxovirus responsible for sporadic outbreaks of severe disease with high case fatality rates in South and Southeast Asia. Human infection occurs through spillover from natural reservoirs, primarily fruit bats, or via human-to-human transmission, and is characterized by a broad clinical spectrum ranging from asymptomatic infection to acute respiratory disease and fatal encephalitis. Following entry via ephrin-B2 and ephrin-B3 receptors, NiV exhibits marked endothelial and neuronal tropism, leading to systemic vasculitis, disruption of the blood–brain barrier, and direct infection of the central nervous system. Disease progression is driven by a complex interplay between viral replication strategies and host immune responses. NiV effectively counteracts innate immunity through multiple viral proteins that inhibit interferon signaling, while simultaneously inducing dysregulated inflammatory responses that contribute to tissue damage and multi-organ failure. Neurological involvement represents the most severe manifestation, often resulting in acute or relapsing encephalitis with long-term sequelae among survivors. Despite the severity of the disease, no licensed antiviral therapies or human vaccines are currently available. Therapeutic development has focused on neutralizing monoclonal antibodies targeting viral glycoproteins and small-molecule antivirals that inhibit viral RNA synthesis, both of which show promising results in preclinical models, but remain limited by timing and translational challenges. In parallel, several vaccine platforms—including viral vectors, mRNA-based constructs, and recombinant protein subunits—have advanced to early-phase clinical trials, demonstrating encouraging immunogenicity. Beyond biomedical interventions, effective outbreak containment relies on integrated public health strategies. The “Kerala model” highlights the importance of rapid case identification, isolation, contact tracing, and community engagement within a One Health framework to mitigate transmission and reduce mortality. This review synthesizes the current knowledge on NiV pathogenesis, immune evasion, clinical manifestations, and emerging therapeutic and vaccine strategies, while highlighting critical gaps and future directions for improving the preparedness and response to this high-consequence emerging pathogen. Full article