Search Results (1,638)

Ebola virus disease remains one of the most serious viral infections with no approved small-molecule treatments. The Ebola virus glycoprotein (EBOV-GP), which enables the virus’s entry to host cells, is a promising target for drug discovery. In this study, a multistage computer-aided drug discovery approach was used to identify new specific EBOV-GP inhibitors. A reliable QSAR model was built using 55 terpenoid derivatives. This model was able to predict the activity of newly designed compounds with good accuracy and validated statistical metrics ($R_{tr}^2$= 0.70; $R_{ext}^2$ = 0.73). It was subsequently applied to screen over 15,500 newly generated compounds from three lead molecules by fragment-based design tools. Predicted activity, binding affinity toward EBOV-GP, and good ADMET drug-like properties prioritized the eleven most promising hits. Through 150 ns molecular dynamics simulations, these compounds remained stable in the EBOV-GP binding site. Further binding free energy analysis (MM/PBSA) showed strong binding affinities, especially for the compounds L-60, L-832, M-1618, and L-1366. This study showed how combining QSAR, fragment-based design, docking, ADMET, and molecular dynamics could help in identifying potent and safe small molecules against the EBOV-GP. The top compounds are ready for further experimental and in vitro biological testing. Full article

The rapid evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) underscores the need for antivirals that are resilient to resistance. Current Food and Drug Administration (FDA)-approved therapies primarily target single viral mechanisms, leaving gaps in efficacy. Here, we developed a Deep Learning-based Activity Screening Model (DLASM), which integrates graph convolutional network with machine learning to identify SARS-CoV-2 inhibitors, using experimental 3-chymotrypsin-like (3CL) main protease assay data. The optimized DLASMs virtually screened ~170,000 compounds from diverse in-house collections and yielded novel hits, several of which not only inhibited the 3CL protease but also blocked viral entry by interfering with heparan sulfate-mediated host interactions. These activities were validated through multiple assays, including 3CL enzymatic inhibition, SARS-CoV-2 pseudotyped particle entry, α-synuclein fibril uptake as a proxy for endocytosis, live virus cytopathic effect, heparan sulfate-dependent entry assay, and a 3D human lung mucociliary tissue model. Molecular docking studies elucidated binding modes at the 3CL protease active site, while molecular dynamics simulations provided insights into compound–heparan sulfate interactions. The identified compounds represent early-stage hits with moderate potency that demonstrate dual-mechanism antiviral activity. Together, these findings establish dual-target inhibition as a promising antiviral strategy, offering not only enhanced potency but also reduced risk of resistance. Moreover, our DLASM framework provides a generalizable pipeline for identifying chemically diverse scaffolds and for broader applications beyond SARS-CoV-2. Full article

Addressing principal challenges in common bean (Phaseolus vulgaris L.) breeding requires a holistic approach. A combined strategy was implemented to assess seven genotypes (landraces and commercial varieties) for yield potential, stability and resistance to bean common mosaic virus (BCMV) under Mediterranean low-input conditions. Pure-line selection and prognostic breeding together with SSR and CAPS-SCAR marker-assisted selection (MAS) formed the core methodology. Significant variation was detected across 24 morpho-agronomic descriptors, while SSR revealed 48.57% polymorphic loci and private alleles in specific landraces. High genetic coefficients of variation and high heritability were recorded for yield-related traits. Phenotypical evaluation showed diverse responses to BCMV, with mild symptoms predominating (52.14%). Entries G1 (45%) and G5 (35%) exhibited the highest frequency of the symptomless resistant phenotype. Molecular screening at I and bc-3/eIF4E loci confirmed G5’s robust dominant I gene profile, while G1 included individuals carrying both the dominant I gene and recessive bc-3, offering a valuable source for pyramiding resistance. Additionally, G1 (LI = 2.35; 100%) performed strongly in productivity, whereas G2 (SI = 3.1; 100%) and G7 (SI = 2.8; 89.7%) exhibited exceptional stability. Overall, the mixed-model approach highlighted the complementary characteristics of the tested genotypes and identified G1, G2, G5 and G7 as promising candidates for future breeding programs targeting high yield, low-input adaptability and resistance to BCMV. Full article

Canine coronavirus (CCoV), an alphacoronavirus belonging to the Coronaviridae family, is primarily associated with enteric infections in dogs. The ongoing evolution of coronaviruses through genetic recombination and mutation leads to the emergence of novel strains with increased pathogenicity, thereby raising the risk of cross-species transmission and spillover events. In this context, viral entry inhibitors represent a promising strategy, as they can serve as pivotal tools to prevent initial infection and subsequent viral replication. The S2 subunit of the spike (S) glycoprotein contains two heptad repeat regions (HRN and HRC), which play essential roles in the conformational changes required for viral fusion. In this study, we describe the design, synthesis, and functional evaluation of a peptide derived from the HRC domain of the CCoV S glycoprotein. First, we assessed the cytotoxicity of the CCoV-HRC peptide in two cell lines, HE293T and A72, and determined CC₅₀ values > 100 μM. At non-toxic concentrations, the peptide effectively blocked membrane fusion mediated by the CCoV S glycoprotein and significantly reduced viral infection, as demonstrated both in cell–cell fusion assays and in live virus experiments. These findings were supported by in silico docking and molecular dynamics simulations, which provided structural insight into the interaction between CCoV-HRC and the S fusion core. Then, molecular analyses were conducted to evaluate the expression of the gene encoding the viral S protein, confirming the antiviral potential of CCoV-HRC peptide. Overall, these findings provide a solid foundation for the development of peptide-based therapeutics to treat or prevent CCoV infections. Full article

Caprine herpesvirus 1 (CpHV-1) is responsible for significant economic losses in goat farming. The CpHV-1 genital infection in goats has been used as a homologous animal model for the study of human herpes simplex virus type 2 (HSV-2). This study aimed to investigate the in vitro virucidal and antiviral effect of lemon juice (LJ) and its main component, citric acid (CA), against CpHV-1 on Madin-Darby Bovine Kidney (MDBK) cells. Cytotoxicity was assessed using an XTT assay, while viral titers were determined by the Reed–Muench method and viral DNA was quantified via qPCR. Pure LJ (pH 2.3) and its corresponding CA solution demonstrated potent and rapid virucidal activity, reducing the viral titer by over 5.0 log10 TCID₅₀/50 µL within 1 min. When applied after viral entry, a non-cytotoxic dilution of LJ (pH 4.32) significantly inhibited viral replication, causing a 2.5 log10 TCID₅₀/50 µL reduction in viral titer and a corresponding decrease in viral DNA. The antiviral effects were minimal at a near-neutral pH of 6.67, probably interacting with envelope structures. These results suggest that LJ could be a potential low-cost topical agent or disinfectant for controlling CpHV-1 in goat populations and offer a basis for translational research on human herpesviruses. Full article

Avian reovirus (ARV) is a major poultry pathogen recently recognized for its potential as an oncolytic virus that selectively infects and kills cancer cells without harming healthy human cells. However, the receptors mediating ARV entry into cancer cells remain unclear. Using mouse melanoma B16-F10 cells as a model, this study identified ARV-binding receptor candidates through viral overlay protein binding assay (VOPBA), SDS-PAGE, and LC-MS/MS analysis. Plaque-forming assays (PFAs) evaluated viral replication efficiency, while co-immunoprecipitation (Co-IP) and proximity ligation assay (PLA) confirmed direct interactions between viral σC and host receptor proteins. Functional assays using shRNA knockdown and antibody blocking demonstrated that inhibition of Plg-RKT expression markedly reduced ARV infection. Western blot analysis revealed that ARV binding to Plg-RKT activates Src and p38 MAPK signaling pathways, which promote caveolin-1 phosphorylation and caveolae-mediated endocytosis. These findings identify Plg-RKT as a crucial receptor mediating ARV σC binding and entry into B16-F10 melanoma cells. Furthermore, activation of Src-p38 MAPK signaling was shown to be essential for viral internalization. This study elucidates the molecular mechanism underlying ARV entry into melanoma cells and provides valuable insight for improving the selectivity and therapeutic potential of ARV as an oncolytic virus. Full article

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne viral disease with high case–fatality rates in East Asia, yet no licensed vaccines are currently available. Here, we generated attenuated severe fever with thrombocytopenia syndrome virus (SFTSV) strains through serial passage in Huh-7 cells and evaluated their pathogenicity, immunogenicity, and protective efficacy. Attenuation candidates were selected based on reduced pathogenicity, estimated based on the median lethal dose (LD₅₀), and genetic sequencing was performed to identify mutations associated with attenuation. In C57BL/6 IFNAR⁻/⁻ mice, the attenuated strain exhibited markedly reduced virulence and viral loads while inducing robust virus-specific IgG, neutralizing antibody, and cellular immune responses. Notably, immunization with the attenuated strain conferred complete protection against lethal challenge with heterologous SFTSV genotypes. Genomic analysis revealed nonsynonymous mutations in the RNA-dependent RNA polymerase (RdRp), glycoprotein, and NSs genes, implicating alterations in viral replication, entry, and immune evasion. Collectively, these findings demonstrate that serial cell-culture passage can generate attenuated SFTSV strains that retain strong immunogenicity and cross-protective efficacy, supporting their potential as live-attenuated vaccine candidates for SFTS. Full article

Respiratory syncytial virus (RSV) poses a substantial global health burden, particularly in infants and the elderly. The fusion (F) protein is a key therapeutic target for inhibiting RSV entry. In this study, we performed a structure-based virtual screening of the Comprehensive Marine Natural Products Database (CMNPD) to discover novel anti-RSV agents targeting the prefusion F protein trimer. Screening of 31,561 compounds via molecular docking, followed by stringent ADMET (absorption, distribution, metabolism, excretion, and toxicity) profiling and MM/GBSA (Molecular Mechanics/Generalized Born Surface Area) binding free energy calculations, identified 11 promising candidates. Among these, manzamine alkaloids exhibited the most favorable docking scores (as low as −13.3 kcal/mol) and promising Ligand Efficiency (LE) values. These molecules primarily interact with conserved hydrophobic residues (Phe140, Phe488) through hydrophobic interactions, π-stacking, and electrostatic forces. Our study highlights marine natural products, especially manzamine alkaloids, as promising leads for the development of novel, orally bioavailable RSV fusion inhibitors, potentially offering avenues to overcome existing drug resistance. However, these computational findings require in vitro validation to confirm efficacy. Full article

Porcine epidemic diarrhea (PED) is a severe and highly contagious enteric disease of pigs caused by porcine epidemic diarrhea virus (PEDV). The spike (S) protein of PEDV is the main driving force for viral entry into host cells, influencing the pathogenicity and virulence of the virus subgroup. Currently, the S gene of PEDV exhibits a wide array of variations, with numerous mutations reported. Consequently, recent studies on the phylogenetic classification of PEDV have categorized these variants into clusters or lineages. In this study, 161 PEDV subgroups, including 58 Korean isolates and 103 global PEDV reference subgroups, were classified into two groups, G1 and G2, with nine subgroups (G1a, G1b, G1c, G1d, G2a, G2b, G2c, G2d, and G2e) based on the complete S gene. Phylogenetic analysis revealed that the subgroups isolated in Korea between 2021 and 2022, which were previously reported as G2b subgroups, were G2e subgroups, derived as potential recombinants from the G2a and G1d subgroups. These results indicate that PEDV subgroups isolated from Korea may require reclassification based on recently reported subgroups. Full article

Classical swine fever virus (CSFV) remains a significant threat to the global swine industry, causing a highly contagious and often fatal disease in pigs. This review comprehensively examines the molecular biology of CSFV and the intricate mechanisms it employs to establish infection. We detail the structure and functions of viral proteins, highlighting their roles in virus entry, replication, and immune evasion. A major focus is placed on the virus–host interaction, specifically how CSFV subverts host innate immune responses and hijacks critical cellular processes, including metabolism and cell death pathways. The virus strategically manipulates host cell death programs (apoptosis, mitophagy, necroptosis) and exploits intracellular transport systems to promote its propagation. Furthermore, we summarize recent advances in understanding the cellular receptors involved in CSFV entry and the role of exosomes in viral spread. This synthesis of current knowledge aims to provide a deeper insight into the pathogenesis of CSFV and identify potential vulnerabilities that could be targeted for the development of novel antiviral strategies. Full article

Daphnis nerii can severely damage pine forests worldwide. Daphnis nerii cypovirus-23 (DnCPV-23) is an important viral pathogen for controlling D. nerii. However, the mechanism underlying DnCPV-23 cell entry has not been elucidated. In this study, we determined that VP3 mediates the binding of DnCPV-23 to host brush border membrane vesicles. Far-Western blotting and mass spectrometry results revealed that a Manduca sexta alpha-glucosidase (MsAGL) can interact with VP3. The interaction between MsAGL and VP3 was verified by co-immunoprecipitation and glutathione S-transferase pull-down assays. Notably, MsAGL influenced DnCPV-23 entry into host cells, including attachment and the subsequent internalization of the virus. Furthermore, MsAGL inhibited DnCPV-23 infections of M. sexta cells and D. nerii larvae. In summary, we confirmed that VP3 of DnCPV-23 mediates cell entry, while also identifying MsAGL as an entry factor for DnCPV-23. The study findings provide useful insights relevant for further elucidating the cell entry mechanisms of cypoviruses. Full article

Hepatitis A virus (HAV) infection can occasionally cause acute severe hepatitis. Patients with this disease sometimes need to undergo liver transplantation with immunosuppressants. Although rare, breakthrough HAV infections, despite vaccination, appear to be more common among immunocompromised populations. The effect of immunosuppressants on HAV replication is unclear. In this study, we examined the effects of immunosuppressants on HAV HA11-1299 genotype IIIA replication in human hepatocytes, finding that azathioprine inhibited HAV replication with a half-maximal inhibitory concentration of 0.967 μmol/L. We further examined the effect of azathioprine on the replication of HAV HM175 18f genotype IB using replication-competent or replication-incompetent subgenomic replicon in HuhT7 cells. Azathioprine had significant inhibitory effects on the HAV replication-competent subgenomic replicon compared to the replication-incompetent subgenomic replicon. The effect of azathioprine on the activity of the HAV HM175 18f genotype IB-internal ribosomal entry site (IRES) was investigated in COS7-HAV-IRES cells using a reporter assay. Azathioprine at 1 μmol/L had a significant inhibitory effect on HAV IRES activity but at 0.5 μmol/L had no inhibitory effect. Azathioprine appears to inhibit HAV replication as well as HAV translation. In conclusion, we found that azathioprine inhibits HAV replication in human hepatocytes, meaning that it may be useful for patients with a HAV infection who need to use immunosuppressants. Full article

The endo-lysosomal channel TRPML2 regulates key processes like membrane trafficking and autophagy, which are hijacked by many RNA viruses during endocytic entry. However, the development of TRPML2-targeted therapeutics has been hindered by a notable lack of high-affinity and selective peptide-based activators. Scorpion venom peptides, honed by evolution for exceptional specificity toward diverse membrane ion channels, represent a promising, underexplored natural library for discovering novel pharmacological probes and drug leads. Here, we screened and identified seven candidate peptides interacting with TRPML2 using co-immunoprecipitation combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of the Mesobuthus martensii venom. Based on molecular docking analysis, the top four candidates—MMTX, BmP05, BmTX1, and BmKK12—were selected for chemical synthesis, oxidatively cyclized to form their native disulfide-bridged conformations, and subsequently purified and characterized by analytical HPLC and MS. Calcium imaging confirmed that two of the four oxidized peptides, BmP05 and BmKK12, exhibited superior potency in inducing a sharp increase in Ca²⁺ influx. Crucially, BmP05 and BmKK12 demonstrated potent, concentration-dependent inhibition of Zika virus (ZIKV) replication at the RNA level at non-cytotoxic concentrations, whereas the weaker activators MMTX and BmTX1 did not. The current study first reports animal venom-derived peptides that function as specific TRPML2 agonists with concomitant antiviral activity. Together, our findings provide not only new molecular probes for dissecting TRPML2 biology but also a pioneering strategy for developing host-directed, broad-spectrum therapeutics against viruses dependent on endo-lysosomal entry. Full article

The MERS-CoV (Middle East respiratory syndrome coronavirus) is a zoonotic virus with a high mortality rate and a lack of antiviral drugs, underscoring the need for effective therapeutic methods. Viral entry depends on interactions between viral surface proteins and human receptors, with Dipeptidyl Peptidase-4 (DPP4), a transmembrane glycoprotein, acting as the receptor for MERS-CoV. We employed Molecular Dynamics (MD) Simulations to identify critical interface residues under a high-performance computing (HPC) workflow for accelerated results. Target residue pairs were identified through analysis of salt bridge and hydrogen bond occupancy. The stability of these residues was confirmed through three independent MD Simulations at human body temperature and constant pressure. Additionally, binding affinity predictions were calculated to determine the interaction strength between the virus and human receptors. Applying the scientific threshold criteria, we narrowed our results to seven key interaction pairs; two of the identified pairs (Asp510-Arg317, and Arg511-Asp393) are consistent with findings published in previous research studies, and five novel interactions are proposed for future experimental studies with our active collaborators in Pharmacology. The results provide a molecular basis for targeted mutation-based experiments and support the rational design of structure-based inhibitors aimed at disrupting the MERS-CoV-DPP4 complex, thereby facilitating the translation of computational findings into antiviral drug discovery. Full article

Flaviviruses such as dengue virus (DENV) and Zika virus (ZIKV) co-circulate widely and cause significant morbidity, yet effective broad-spectrum antivirals are limited. This study evaluated the antiviral efficacy, cytotoxicity, and host transcriptional responses to the nucleic acid–hydrolyzing antibody fragment 3D8 scFv in mono- and co-infection models. RNA sequencing of A549 cells treated with 3D8 scFv revealed a dose-dependent activation of the MAPK–HSP70 stress response, with minimal transcriptomic disruption at antiviral concentrations. Comparative transcriptomic analysis identified distinct host signatures for ZIKV and DENV2, and machine learning classifiers accurately distinguished infection states (AUC > 0.95). In Vero E6 cells, prophylactic treatment with 3D8 scFv significantly reduced viral RNA, protein expression, and infectious particle production for both viruses, including during co-infection. Optimized post-entry treatment also demonstrated antiviral activity. Cytotoxicity assays confirmed good tolerability at effective concentrations. These findings indicate that 3D8 scFv inhibits viral replication through early cleavage of viral nucleic acids while inducing a limited protective stress response, supporting its development as a broad-spectrum antiviral candidate. Full article