Search Results (2,903)

Antiviral drug resistance in SARS-CoV-2 is increasingly limiting treatment efficacy. Four recent studies have revealed two key resistance mechanisms: (1) Mutations in the main protease (M^pro)—including E166V, E166A, and S144-series variants—disrupt drug binding or active-site conformation, reducing nirmatrelvir efficacy. (2) The proofreading exoribonuclease (ExoN) removes incorporated nucleoside analogues (e.g., bemnifosbuvir, sofosbuvir), conferring resistance. Guided by structural and pharmacological insights, three effective countermeasures have been established: structure-based optimization of M^pro inhibitors, rational design of ExoN-evading nucleoside analogues, and synergistic combination therapies. These advances provide a solid framework for developing next-generation antivirals to combat emerging resistant SARS-CoV-2 variants. Full article

Oncogenic viruses contribute to approximately 20% of human cancers globally, with their impact falling disproportionately on populations in Sub-Saharan Africa. In this region, cervical cancer, hepatocellular carcinoma, endemic Burkitt lymphoma, and Kaposi sarcoma represent major causes of cancer-related morbidity and mortality, driven by persistent infection with human papillomavirus (HPV), hepatitis B and C viruses (HBV/HCV), Epstein–Barr virus (EBV), Kaposi sarcoma-associated herpesvirus (KSHV), and human T-lymphotropic virus-1 (HTLV-1). This review synthesizes current insights into the immunological mechanisms that underpin viral carcinogenesis in Africa, emphasizing how defective viral clearance, chronic immune activation, and immune evasion arise from the convergence of region-specific co-infections, host genetic diversity, and environmental exposures. We examine the mechanistic roles of HIV-associated CD4⁺ T cell depletion, malaria-induced perturbation of antiviral T cell immunity, helminth-driven T helper 2 polarization, and tuberculosis-associated inflammatory signaling in promoting viral persistence and malignant transformation. In addition, the influence of the extensive diversity of African human leukocyte antigens (HLA) and cytokine gene polymorphisms on antiviral immune responses and cancer susceptibility was discussed. We also assessed how virus-associated tumors establish profoundly immunosuppressive microenvironments characterized by impaired antigen presentation and the dominance of immune checkpoint pathways. Finally, we examined how gaps in vaccination, screening, and diagnostic capacity intersect with immunological vulnerability across Africa, contributing to the burden of infection-associated cancers. These challenges position Africa as a critical setting for developing targeted, genotype-inclusive public health interventions and reducing global cancer disparities through advances in immunoprevention and immunotherapy. Full article

Human cytomegalovirus (CMV) remains a significant infectious complication after kidney transplantation, reflecting gaps in the understanding of the molecular and immunological mechanisms regulating the transition from latency to productive infection. Following primary infection, CMV establishes lifelong latency in hematopoietic and myeloid lineage cells, maintained by viral chromatin repression and robust CMV-specific immune surveillance. CMV reactivation is associated with graft dysfunction, increased risk of rejection, opportunistic infections, and reduced patient survival. In kidney transplantation, CMV reactivation is driven by the interplay between tissue injury, inflammation, and immunosuppression. Ischemia–reperfusion injury and peri-operative stress produce reactive oxygen species, DNA damage, and pro-inflammatory cytokines (e.g., TNF-α, IL-6), which activate transcription factors such as NF-κB and AP-1. These factors regulate the CMV major immediate-early promoter (MIEP), thereby triggering lytic viral gene expression. At the same time, immunosuppressive therapies impair antiviral immune surveillance and, in some cases, induce cytokine release, potentially contributing to the pro-inflammatory environment that favors viral reactivation. In this review, we summarize current molecular and immunologic mechanisms governing CMV latency and reactivation with a focus on how immunosuppressive strategies and injury-associated pathways converge to promote CMV reactivation. We also discuss implications of risk stratification and the development of targeted therapeutic strategies to prevent CMV reactivation in kidney transplant recipients (KTRs). Full article

Urtica dioica L. (stinging nettle) is a perennial herb with a long ethnomedicinal history and diverse pharmacological potential. This comprehensive review consolidates current knowledge on its phytochemistry, extraction technologies, bioactivities, and molecular mechanisms. However, recent reviews have generally addressed these aspects separately, and an integrated assessment linking green extraction technologies and phytochemical profiles to molecular mechanisms and gene expression modulation is still lacking. U. dioica contains abundant polyphenols (rutin, quercetin, kaempferol, and chlorogenic acid), sterols (β-sitosterol and stigmasterol), vitamins, carotenoids, and the antiviral lectin Urtica dioica agglutinin (UDA). Advances in green extraction technologies, such as ultrasound-assisted extraction, microwave-assisted extraction (MAE), pressurized liquid extraction, and natural deep eutectic solvent (NADES)-based systems, have significantly improved yield, purity, and environmental sustainability compared to conventional maceration and Soxhlet methods. Comprehensive chromatographic and spectroscopic profiling (HPLC, GC–MS, FTIR, NMR, and LC–MS/MS) has established detailed chemical fingerprints linking bioactive constituents to antioxidant, anti-inflammatory, antimicrobial, and antiviral properties. Mechanistic studies reveal that U. dioica exerts its therapeutic effects through modulation of oxidative stress, inhibition of the NF-κB and COX-2 pathways, enhancement of endogenous antioxidant enzymes, and regulation of apoptotic gene expression. Moreover, NADES–MAE extracts demonstrate potential as sustainable, high-efficacy formulations for nutraceutical and cosmetic applications. Despite extensive preclinical evidence, clinical standardization and dosage optimization remain major challenges. This review underscores U. dioica as a multifunctional medicinal plant with significant promise for next-generation phytotherapeutics and molecular nutrition. Full article

West Nile virus (WNV) is a mosquito-borne pathogen of escalating epidemiological importance and a growing global health concern, driven by the climate-associated expansion of its Culex mosquito vectors. Although WNV is an extensively studied flavivirus, most host–pathogen interaction studies focus on static and structural aspects rather than dynamic and functional ones. Delineating phosphorylation-mediated interactions between WNV proteins and human kinases bridges a critical gap by providing important insight into the molecular mechanisms underlying infection. In this study, we investigated potential phosphorylation-mediated interactions between WNV proteins and human kinases using an integrative computational framework combining motif prediction, phosphoproteomic data analysis and structural docking. Key interactions were predicted between viral proteins and regulatory kinases within the AKT-ERK pathway and the AMPK-mediated autophagy, including major network kinases such as RAF1, IKBKB, and ULK1. In addition, experimentally validated phosphorylation sites in viral proteins were found to be associated with multiple candidate host kinases, including MAP2K7 and MAP2K9, suggesting complex regulatory networks. Integration with phosphoproteomic datasets supported the relevance of multiple predicted kinases, including those associated with antiviral responses and translational regulation. Protein–protein docking demonstrated stable, energetically favorable interactions between selected host kinases and viral proteins, particularly the viral polymerase (NS5), helicase (NS3), and NS1. The findings of this study establish a framework for future research on the development of host-directed antiviral strategies. Full article

The innate immune system provides the first line of defense against invading pathogens and relies on tightly regulated mechanisms to initiate and resolve inflammatory responses. In addition to transcriptional control, post-transcriptional regulation of messenger RNA (mRNA) plays a critical role in determining the magnitude and duration of immune responses. Among those key regulators, the ZFP36 family of CCCH-type zinc-finger RNA-binding proteins, including ZFP36, ZFP36L1, and ZFP36L2, plays a central role in controlling the stability and translation of inflammatory, immune-related, and viral RNAs. This review focuses on the ZFP36 family of RNA-binding proteins and highlights their emerging roles in inflammation, immune cell development and differentiation, and antiviral immunity, with a particular focus on ZFP36L1 and ZFP36L2. Recent evidence has identified ZFP36L1 as a broad-spectrum antiviral factor that restricts multiple RNA viruses through distinct molecular mechanisms. A detailed understanding of the molecular mechanisms underlying ZFP36L1- and ZFP36L2-mediated antiviral activity and immune regulation will facilitate rational development of host-directed antiviral therapeutics and their strategic integration with vaccination strategies to limit viral replication, shedding, and transmission, thereby improving the control of emerging and re-emerging viral diseases. Full article

Purpose: To characterize the messenger RNA (mRNA) and microRNA (miRNA) expression profiles of the normal human cornea and conjunctiva using impression cytology (IC) samples and to investigate their molecular characteristics and regulatory networks. Methods: Corneal and conjunctival IC samples were collected from healthy subjects. Whole-transcriptome and miRNA sequencing were performed, followed by differential expression and bioinformatics analyses. Regulatory networks, protein interaction networks, and functional enrichment analyses were constructed. Selected genes and miRNAs were validated by RT-qPCR. Results: A total of 1676 differentially expressed genes and 175 differentially expressed miRNAs were identified between the cornea and conjunctiva. Functional analyses revealed that genes showing higher expression in the cornea were mainly associated with epithelial structure, barrier function, and antiviral immune responses. In contrast, genes showing higher expression in the conjunctiva were primarily involved in immune regulation, secretion, metabolic detoxification, and tissue remodeling. PPI network analysis showed that hub genes in the cornea were predominantly interferon-stimulated genes related to antiviral responses, while those in the conjunctiva were mainly involved in cell cycle regulation and metabolic detoxification. GO and KEGG analyses further supported these functional distinctions. RT-qPCR validation generally supported the expression patterns identified by RNA sequencing. Conclusions: Our findings reveal that the cornea is characterized by gene expression programs supporting epithelial homeostasis, barrier function, and antiviral immunity, whereas the conjunctiva exhibits transcriptional signatures related to immune surveillance, secretion, metabolic processing, and tissue remodeling. The miRNA–mRNA regulatory networks constructed in this study provide new insights into the molecular regulatory mechanisms of the ocular surface and offer a theoretical basis for future research into disease mechanisms and targeted therapeutic strategies. Full article

Enterovirus A71 (EV-A71) is a major causative agent of hand, foot, and mouth disease, yet no specific antiviral therapy has been approved. This study systematically evaluated the efficacy and mechanisms of alkaloids against EV-A71 infection by integrating meta-analysis, network pharmacology, and molecular docking. Nine animal studies were included. Meta-analysis suggested that alkaloid intervention significantly improved survival (OR = 30.62, 95% CI: 10.44–89.82), reduced clinical severity, attenuated body weight loss, and decreased viral loads in infected tissues. Subgroup analyses preliminarily suggested that quinolizidine alkaloids and high-dose regimens (>5 mg/kg) may be associated with preclinical intervention effects. Network pharmacology predicted 155 shared targets between seven active alkaloids and EV-A71-related genes, with MAPK1, MAPK3, JUN, AURKB, and MAPK8 recognized as core targets through computational screening. Functional enrichment analysis suggested significant involvement of the MAPK, TNF, and IL-17 signaling pathways. Molecular docking provided computational support for stable binding affinities between active alkaloids and core targets (−6.7 to −9.3 kcal/mol). Collectively, these findings suggest that alkaloids exert anti-EV-A71 effects through both direct antiviral activity and host-directed regulatory mechanisms, supporting their potential as candidates for the development of novel anti-EV-A71 therapeutics. Full article

Chronic wounds constitute a major clinical and socioeconomic burden owing to prolonged inflammation, persistent bacterial infection, impaired angiogenesis, and defective extracellular matrix remodeling. Advanced wound dressings have traditionally been developed to promote tissue regeneration, control bacterial infection, and restore the wound microenvironment. Recent advances have focused on multifunctional biomaterials integrating regenerative, antibacterial, anti-inflammatory, antioxidant, and controlled drug-delivery properties. Within this context, antiviral biointerface engineering has emerged as a promising, although still exploratory, materials-engineering perspective rather than an established function of wound dressings. Hydrogel–metal–organic framework (MOF) hybrid polymer composites have emerged as versatile platforms for multifunctional wound dressings. Hydrogels provide hydrated three-dimensional matrices with tunable porosity, swelling behavior, mechanical compliance, and biocompatibility, whereas MOFs contribute high surface area, adjustable pore architectures, chemically tailorable active sites, and controlled ion release. Their integration generates synergistic systems whose performance is governed by structure–function relationships involving polymer crosslinking density, MOF dispersion, pore hierarchy, interfacial adhesion, swelling dynamics, and surface functionalization. Collectively, these parameters regulate mass transport, mechanical stability, therapeutic delivery, and cytocompatibility while potentially influencing virus–material interactions through engineered biointerfaces. Current evidence indicates that direct experimental demonstrations of antiviral performance in hydrogel–MOF wound dressing systems remain limited. Accordingly, antiviral biointerface functions should be regarded as emerging engineering opportunities requiring further experimental validation before clinical translation. This review critically analyzes the structure–function engineering principles governing hydrogel–MOF hybrid systems and examines how established regenerative functions may be integrated with emerging antiviral biointerface concepts. Unlike previous reviews focused primarily on drug delivery, antibacterial activity, or tissue engineering, this review emphasizes the relationships between polymer architecture, MOF chemistry, interfacial design, and transport phenomena while explicitly distinguishing experimentally supported evidence from prospective mechanistic concepts. Particular attention is given to current limitations, translational challenges, and future directions for the rational design of next-generation multifunctional hydrogel–MOF wound dressings. Full article

VISA/MAVS is a central signaling hub that links viral RNA sensing to type I interferon production and inflammatory responses. Because of its potent signal-amplifying capacity, VISA activity must be precisely controlled: insufficient activation compromises antiviral defense, whereas excessive or spontaneous activation can drive chronic inflammation and autoimmune disease. Recent studies have revealed a complex regulatory network governing VISA signaling, involving post-translational modifications, dynamic protein interactions, selective degradation pathways, metabolic cues, and intrinsic inhibitory mechanisms that collectively determine its activation threshold, signaling duration, and downstream output. In this review, we discuss the molecular mechanisms that regulate VISA activation, signal propagation, signal termination, and quiescence maintenance under resting conditions. We propose that immune homeostasis is achieved not through a simple on–off switch, but through continuous regulation of the VISA signalosome life cycle. This framework provides an integrated view of VISA and offers new insights into the molecular mechanisms underlying immune homeostasis. Full article

Chronic obstructive pulmonary disease (COPD) is a progressive lung disorder that affects millions of people globally. Although the mechanisms of COPD pathogenesis are not completely known, oxidative stress and lung inflammation caused by chronic exposure to cigarette smoke, environmental or occupational pollutants, gas from burning biomass fuel are thought to contribute to development of COPD. Therefore, therapies aimed at reducing oxidative stress along with inflammation may be important in treating COPD. However, the current pharmacological therapies treat symptoms and reduce acute exacerbations, but do not treat the root cause of COPD. Quercetin is a plant polyphenol present in berries, apples and onions, and has potent antioxidant and anti-inflammatory properties. Quercetin inhibits oxidative stress by scavenging reactive oxidant species and promoting expression of antioxidant enzymes. It reduces inflammation by inhibiting various kinases that participate in the expression of pro-inflammatory cytokines. It also alters gene expression by functioning as an epigenetic modifier. Quercetin also acts as antiviral agent by attenuating viral entry and replication. In preclinical models of COPD, quercetin reduces oxidative stress, lung inflammation, goblet cell metaplasia, expression of matrix metalloprotease MMP-9 and MMP-12, and prevents rhinovirus-induced progression of emphysema. It also promotes normal regeneration of airway epithelium by improving cell polarization, reducing goblet cell hyperplasia and increasing number of ciliated cells. This review compiles the current understanding of the biological properties of quercetin and its potential therapeutic role in COPD. We also summarize its potential benefits over the current therapeutic drugs used to treat COPD. Full article

Chalcones are naturally occurring open-chain flavonoids widely distributed in plants and recognized for their broad spectrum of pharmacological activities. Their versatile scaffold allows for extensive structural modifications, leading to a diverse range of natural and synthetic derivatives with notable biological potential. In the context of viral infections, chalcones have demonstrated remarkable efficacy against a variety of human pathogens, including dengue virus, HIV, HCV, influenza A, SARS-CoV-2, and other emerging viruses. Beyond human health, several chalcones have shown potent activity against plant viruses such as tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV), and animal viruses including porcine reproductive and respiratory syndrome virus (PRRSV) and mammalian reovirus (MRV), underscoring their broad antiviral spectrum. These compounds act through multiple mechanisms, including the inhibition of viral enzymes (e.g., proteases, polymerases, and integrases), interference with viral entry and replication, and the modulation of host-related pathways. Recent advances in molecular docking, structure–activity relationship (SAR) studies, and synthetic optimization have further highlighted chalcones as a promising scaffold for antiviral drug discovery. Accordingly, this review summarizes and categorizes antiviral chalcones reported over the last two decades, emphasizing and critically discussing their molecular targets, mechanisms of action, and pharmacological potential as lead compounds. It also provides a comparative perspective on their pharmacological relevance by correlating their activities against standard therapeutic agents and reference inhibitors. Furthermore, the most recurrent viral targets were critically discussed regarding their conservation, expected genetic barriers to resistance, and the global SAR trends identified for the corresponding antiviral chalcones. Finally, in silico ADMET profiling of the most promising naturally occurring chalcones was performed to evaluate their drug-likeness and pharmacokinetic properties, offering guidance for future structural optimization and translational development. Collectively, these findings highlight the chalcone scaffold as a versatile platform for the development of novel antiviral agents targeting diverse viral and host pathways. Full article

The increasing presence of SARS-CoV-2 antivirals (SASs) in wastewater threatens aquatic ecosystems, making it necessary to better understand their removal efficiency during biological treatment. This study evaluates the removal percentages, kinetic mechanisms, and toxicity profiles of six SASs, daclatasvir (DCV), darunavir (DRV), favipiravir (FAV), lopinavir (LOP), remdesivir (REM), and ritonavir (RIT), using activated sludge. A full factorial design combined with response surface methodology (RSM) was used to assess the impact of pH, temperature (T), and mixed liquor suspended solids (MLSS) on SAS removal and microbial stability. The results distinguished two dominant removal pathways. DCV and LOP were primarily removed by adsorption, whereas DRV, FAV, REM and RIT were predominantly removed through biodegradation involving enzymatic transformation and bacterial co-metabolism. RSM achieved a desirability score of 0.772 and identified the optimal operating conditions (pH = 6.08, MLSS = 4.41 g/L, and T = 44.99 °C), resulting in removal efficiencies above 93% for all compounds except DRV, which remained the limiting compound with a maximum removal efficiency of 66%. Perturbation analysis showed that all tested factors have a distinct influence on process performance. These established kinetic trends should support further investigations into advanced biological wastewater treatment methods and precise ecotoxicity profiling of emerging biotransformation products. Full article

Porcine reproductive and respiratory syndrome, a highly contagious disease, poses a severe threat to the global swine industry. Its causative agent, PRRSV, induces reproductive disorders (abortion, stillbirth) in pregnant sows and respiratory disease in piglets. The host immune system is disrupted by PRRSV, and no specific antiviral drugs are currently available. Thus, vaccination is regarded as the primary strategy for PRRS prevention and control. GP4, a key minor structural protein of PRRSV with an estimated molecular weight of 32 kDa, contains four conserved N-glycosylation sites at residues 37, 84, 120 and 130. Critical neutralizing epitopes are harbored in its extracellular domain (amino acids 40–79). PRRSV binding to the host CD163 receptor is mediated by GP4, which also regulates viral assembly and release, and induces protective immune responses. Hence, GP4 is identified as a central target for PRRS vaccine development. In this review, GP4’s structural characteristics, genetic evolution and interaction mechanisms are summarized. Its roles in viral life cycle, virulence, immune evasion and potential applications are discussed, providing a theoretical reference for PRRSV control. Full article

Background/Objectives: The lack of effective antiviral therapies for many viral infections highlights the need for the development of new antiviral agents. The broad antiviral effects of glycopeptide antibiotics (GPAs) and their derivatives have been previously described. In our studies, we investigated the in vitro viral inhibitory activity of newly synthesized GPA derivatives against Zika virus (ZIKV), chikungunya virus (CHIKV), o’nyong-nyong virus (ONNV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: Antiviral activity (EC50) and cytotoxicity (CC50) of the active compounds were determined using cell-based assays. The mechanism of action of the lead compound was investigated using binding and entry assays, cell-free virion pre-incubation, a virion destabilization assay, a liposome-based capsid protection assay, and molecular docking analysis. Results: Seven of the compounds were able to inhibit ZIKV and two compounds inhibited all four tested viruses. Among them, a teicoplanin pseudoaglycone derivative, compound 7, showed the strongest antiviral activity, inhibiting all four viruses at low micromolar concentrations. Mechanistic studies demonstrated that compound 7 acts during an early stage of ZIKV infection and inhibits low-pH-triggered virus–liposome fusion. Molecular docking analysis suggested potential interactions between compound 7 and the viral envelope protein that could interfere with the conformational rearrangements required for membrane fusion. Conclusions: The present findings demonstrate that hydrophobic GPA derivatives, particularly compound 7, exhibit promising broad-spectrum antiviral activity in vitro. Whether similar mechanisms contribute to the antiviral activity against other viruses remains unknown. The studied GPA derivatives are promising candidates for further pre-clinical and clinical development as broad-spectrum antivirals. Full article