Search Results (7,022)

The COVID-19 pandemic caused by the SARS-CoV-2 virus has exposed the urgency of research on rapid and efficient virus detection and strategies to inhibit its replication. Previous studies have mostly focused on traditional immunoassay or optical methods, but they have limitations in terms of sensitivity, timeliness, and in-depth analysis of molecular interaction mechanisms. Solid-state nanopore single-molecule detection methods, which can monitor molecular conditions in real time at the single-molecule level, bring new opportunities to solve this problem. The nucleocapsid protein (N protein) of SARS-CoV-2 was systematically investigated under different conditions, such as external drive voltage, pH, nanopore size, and N protein concentration. The translocation of the N protein through the nanopore was then analyzed. Subsequently, we analyzed the translocation characteristics of the N protein, RNA, and N protein–RNA complexes. With the aid of EMSA experiments, we conclusively confirmed that RNA binds to the N protein. Building on this finding, we further explored small molecules that could affect the nanopore translocation of N protein–RNA complexes, such as gallocatechin gallate (GCG), epigallocatechin gallate (EGCG), and the influenza A viral inhibitor Nucleozin. The results show that GCG can disrupt the liquid-phase condensation of the N protein–RNA complex and inhibit the replication of the N protein. Meanwhile, the structural isomer EGCG of GCG and the small molecule Nucleozin can also block RNA-triggered N protein liquid–liquid phase separation (LLPS). Our results confirmed that GCG, EGCG, and Nucleozin exhibit antagonistic effects on the N protein, with differences in their effective concentrations and the potency of their antagonism. Herein, using solid-state nanopore single-molecule detection technology, we developed an experimental method that can effectively detect RNA-induced changes in N protein properties and the regulatory effects of small molecules on the LLPS of N protein–RNA complexes. These findings not only provide highly valuable insights for in-depth research on the molecular interactions involved in viral replication, but also open up promising new avenues for future responses to similar viral outbreaks, the development of a rapid and effective detection method based on solid-state nanopores and single-molecule detection, and antiviral therapies targeting N protein–RNA interactions. Full article

The dedifferentiation of smooth muscle cells (SMCs) is the main cause of atherosclerosis and vascular calcification. This study integrated the gene expression data of multiple microarrays to identify relevant marker molecules. A total of 72 Gene Expression Omnibus (GEO) samples (GSM) were collected from 10 gene expression data series (GSE) and divided into five groups: non-SMC, SMC, atherosclerotic SMC (SMC-ath), calcified SMC (SMC-calc), and treated SMC (SMC-t). The SMC-t group included synthetic SMCs that had undergone treatment to inhibit proliferation, migration, or inflammation. The gene expression data were merged, normalized, and batch effects were removed before differential gene expression (DGE) analysis was performed via linear models for microarray data (limma) and statistical analysis of metagenomic profiles (STAMPs). The genes with expressions that significantly differed were subsequently subjected to protein-protein interaction (PPI) and functional prediction analyses. In addition, the random forest method was used for classification. Twelve proteins that may be marker molecules for SMC differentiation and dedifferentiation were identified, namely, Proprotein convertase subtilisin/kexin type 1 (PCSK1), Transforming growth factor beta-induced (TGFBI), Complement C1s (C1S), Phosphomannomutase 1 (PMM1), Claudin 7 (CLDN7), Calcium binding and coiled-coil domain 2 (CALCOCO2), SAC3 domain-containing protein 1 (SAC3D1), Natriuretic peptide B (NPPB), Monoamine oxidase A (MAOA), Regulator of the Cell Cycle (RGCC), Alpha-crystallin B Chain (CRYAB), and Alcohol dehydrogenase 1B (ADH1B). Finally, their possible roles in SMCs are discussed. This study highlights the feasibility of bioinformatics analysis for studying SMC dedifferentiation. Full article

Background: The binding of glycosaminoglycans (GAG) to Wnt signaling components plays a key regulatory role in bone formation and regeneration. We previously reported de novo designed chemically modified hyaluronan derivatives, named _REGAG (Rationally Engineered GAG), which demonstrated bone-regenerative properties in a mouse calvaria defect model. To gain initial insights into the pharmacological profile of two _REGAG currently under preclinical investigation in mice, we performed a comprehensive in silico investigation of their binding to human and murine serum albumin (HSA and MSA), as it might influence their ADME properties. Furthermore, we evaluated whether _REGAG binding might impact the recognition of well-characterized HSA-binding drugs. Methods: State-of-the-art in silico ADMET tools, docking and molecular dynamics simulations were used to predict and characterize the interaction of _REGAG with HSA and MSA, and to investigate the molecular mechanisms involved at the atomic level. Results: The investigated _REGAG molecules show a consistent binding preference for the FA1 site in both proteins, and an additional preference for the FA7 site in HSA. Their recognition might induce protein conformational changes and alter the functional state. Furthermore, _REGAG’s conformational adaptability is predicted to influence their binding to the FA5/6 and FA8/9 sites of HSA, and to the FA3/4 and FA7 sites of MSA. Conclusions: Our investigations predict the binding of two hyaluronan derivatives to HSA and MSA. The mechanistic insights gained into the molecular recognition of these two _REGAG molecules offer valuable information for their potential clinical application and serve as a rational basis for future molecular design aimed at improving pharmacokinetic properties. Full article

Tumor necrosis factor α (TNF-α) activates the nuclear factor κB (NF-κB) signaling pathway, which promotes the expression of NF-κB-responsive genes, including intercellular adhesion molecule 1 (ICAM-1). We previously reported that cardamonin, a chalcone-type flavonoid, inhibited TNF-α-induced ICAM-1 expression in human lung adenocarcinoma A549 cells. However, the mechanisms by which cardamonin inhibits the TNF-α-induced NF-κB signaling pathway have yet to be elucidated. Therefore, we herein investigated the effects of cardamonin on TNF-α-induced gene expression and the NF-κB-dependent signaling pathway. Cardamonin reduced TNF-α-induced ICAM-1 mRNA expression and NF-κB reporter activity. It did not affect the inhibitor of NF-κB α (IκBα) degradation, but prevented RelA nuclear translocation and binding to the ICAM-1 promoter. Consistent with this result, three other chalcone derivatives (4′-hydroxychalcone, isoliquiritigenin, and xanthohumol) did not affect the degradation of IκBα, but inhibited nuclear RelA translocation. Cardamonin exhibited the same inhibitory profiles in human breast cancer MCF-7 cells and human fibrosarcoma HT-1080 cells. Cysteine 38 (C38) of RelA was not a primary target site of cardamonin because cardamonin inhibited the nuclear translocation of the RelA C38S mutant. An in silico molecular docking analysis confirmed that cardamonin was not positioned close enough to RelA C38 to mediate covalent binding, and also that cardamonin interacted with RelA at different sites. Mutations in these interaction sites abrogated the nuclear translocation of RelA in response to a TNF-α stimulation. The present results demonstrate that cardamonin inhibited the nuclear translocation of RelA and its DNA binding in the NF-κB signaling pathway in response to a TNF-α stimulation. Full article

Background: Virtual screening is a widely adopted technique for the discovery of novel pharmacologically active compounds; however, the risk of identifying false positive hits remains a major challenge. Aim: The aim of this study was to perform a validated structure-based drug design screening to discover multitarget pyrrole-based molecules as selective dual-acting monoamine oxidase (MAO) and acetylcholinesterase (AChE) inhibitors. Methods: The study employed validated docking protocols using Glide (Schrödinger) and GOLD (CCDC), integrating ligand enrichment analysis and robust Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) rescoring. These methods were applied to a custom-designed database of pyrrole-based compounds. The top-ranked hits were synthesized and validated through in vitro tests, demonstrating significant inhibitory activities against MAO-A, MAO-B, AChE, and Butyrylcholinesterase (BChE). Results: The docking protocols achieved favorable hit rates, with 25.93% for AChE inhibitors and 44.44% for MAO-B inhibitors. Additionally, structure–activity relationship analysis revealed key substituent effects that significantly influence binding affinity and selectivity. Two compounds, EM-DC-19 (2-(2,5-dimethyl-1H-pyrrol-1-yl)-3-(2H-imidazol-4-yl)propanoic acid) and EM-DC-27 ([4-(2,5-dimethyl-1H-pyrrol-1-yl)phenyl]acetic acid), were identified as selective MAO-B inhibitors with additional moderate AChE inhibitory activity, demonstrating IC₅₀ values of 0.299 ± 0.10 µM and 0.344 ± 0.10 µM against MAO-B, and 76.15 ± 6.12 µM and 375.20 ± 52.99 µM against AChE, respectively. The absence of statistically significant inhibitory effects of these lead compounds on MAO-A and BChE (IC₅₀ > 100 µM) underscores their selective inhibitory activity towards MAO-B and AChE. Furthermore, both compounds demonstrated low neurotoxicity and significant neuroprotective and antioxidant effects in rat brain synaptosomes, mitochondria, and microsomes. These effects were particularly evident in models of 6-hydroxydopamine-induced neurotoxicity (6-OHDA) and oxidative stress induced by tert-butyl hydroperoxide and Fe²⁺/ascorbic acid. Conclusions: The findings suggest that these multitarget compounds hold promise for further development, with potential for structural modifications to enhance their enzyme inhibitory and neuroprotective properties. Full article

Background/Objectives: Glioblastoma multiforme (GBM) is an aggressive primary brain tumor with limited therapeutic options. Neoantigen-based immunotherapy offers a promising avenue, but its efficacy primarily depends on the ability of somatic mutations to generate immunogenic peptides effectively presented by HLA class I molecules and recognized by cytotoxic T cells, in concert with innate immune mechanisms such as NK-cell activation and DAMP/PAMP signaling. This study aimed to characterize the MHC-I binding diversity of peptides derived from GBM-associated somatic variants, with a particular focus on interactions involving HLA-A68:01 and HLA-B15:01 alleles. These alleles were selected based on their ethnic prevalence and potential structural compatibility with neoepitopes. Methods: Somatic missense variants from TCGA-GBM were filtered using high-confidence genomic databases, including dbSNP, COSMIC, and MANE. Neoepitope prediction was performed across multiple HLA class I alleles using binding affinity algorithms (MHCflurry2). Peptide–HLA interactions were characterized through motif analysis and anchor residue enrichment. Structural modeling of peptide–HLA complexes was conducted using ColabFold (AlphaFold2-multimer v3) to evaluate conformational stability. The population frequency of selected HLA alleles was examined through epidemiological comparisons. Results: Canonical GBM driver mutations (e.g., EGFR, TP53, PIK3R1) are recurrent and biologically relevant, although pharmacological inhibition of EGFR alone has not consistently improved patient outcomes, underscoring the complex signaling redundancy in glioblastoma. HLA-A68:01 exhibited high binding affinity and favorable motif compatibility, supporting its potential for effective neoantigen presentation. HLA-B15:01 was identified as a viable presenter for the EGFR p.Arg108Lys variant. Structural modeling confirmed stable peptide insertion into the MHC-I binding groove, with high-confidence folding and preserved interface integrity. Ethnic distribution analysis revealed varying GBM incidence across populations expressing these alleles. Conclusions: This integrative analysis identified structurally validated, immunogenically promising neoantigens derived from GBM mutations, particularly for HLA-A68:01 and HLA-B15:01. These findings support allele-informed neoepitope prioritization in personalized immunotherapy, especially for patient populations with corresponding HLA genotypes and MHC-I presentation capacity. Full article

Background and Aims: C1q is an autoantigen in different autoimmune disorders, Systemic Lupus Erythematosus (SLE) and Lupus Nephritis (LN) among them. The two functional domains of C1q, the collagen-like region (CLR) and the globular head region (gC1q), are frequently recognized by autoantibodies in SLE and LN when C1q is immobilized. We studied whether autoantibodies to C1q in SLE and LN patients recognized C1q as a soluble autoantigen and whether the act of immobilization was a prerequisite for the recognition of C1q autoepitopes localized on gC1q domains. Methods: The interaction of soluble C1q and its globular fragments ghA, ghB, and ghC with immobilized IgG autoantibodies (and vice versa) from sera of 48 patients with SLE and LN was studied with ELISA. Data were compared using Spearman correlation coefficient. Fluorescence spectroscopy was used to study the interaction between C1q and LN IgG autoantibodies both presented in solution. Results: We found that anti-C1q autoantibodies from SLE and LN patients specifically bound C1q and gC1q fragments, ghA, ghB, and ghC, both as immobilized and soluble antigens. Correlation analysis indicated a negative correlation between the levels of autoantibodies against immobilized and soluble C1q and immobilized and soluble gC1q fragments which indicates different epitopes when these proteins were recognized as autoantigens in soluble and immobilized conformations. Conclusions: Serum C1q in patients with SLE is a target molecule for binding from anti-C1q autoantibodies. The gC1q region undergoes a conformational change in an immobilized and a soluble form, thus exposing different epitope-binding sites. Full article

This study aims to reveal the influence mechanisms of particles to provide a basis for screening high-efficiency foam stabilizers of nanoparticle (NP) and surfactant (SF). Molecular simulation was used, including Stretching Molecular Dynamics (SMD) for liquid film rupture, Mean Squared Displacement (MSD)/Radial Distribution Function (RDF) for water molecule behavior, NP interface tendency analysis, and interface traction force analysis. The system used silica (SiO₂) NPs (silane-modified to adjust hydrophilicity–hydrophobicity), three SFs [DTAB, CHSB, BS12; single/mixed systems], water (liquid phase), and nitrogen (gas phase). NPs need balanced hydrophilicity (to adsorb water) and hydrophobicity (to stay at the gas–liquid interface); 10% silane-modified NPs performed best, with 44% higher critical traction force for film rupture than unmodified NPs, effective water adsorption (molecules within 0.3–0.4 nm), and 12% interface presence probability. SFs (especially mixed systems like DTAB + BS12) attracted NPs to form stable composites, binding more tightly than single SFs and reducing SF mobility. The NP-SF system showed superior stability: DTAB + BS12 + NPs had the highest critical traction force (816.11 kJ·mol⁻¹·nm⁻¹) and longest rupture time (1.61 ns); the traction work required to pull NPs in the composite (2443.87 kJ·mol⁻¹) was much higher than that required for pure NPs (991.63 kJ·mol⁻¹). Finally, an experiment was conducted to measure the initial foam volume and drainage half-life of different systems to verify the simulation results. Full article

Affibody molecules have emerged as versatile protein engineering platforms due to their exceptional binding properties. These small (6.5 kDa) three-helix bundle proteins, derived from the Z-domain of Staphylococcal protein A, can be engineered to bind diverse molecular targets with high affinity and specificity. This structural and functional versatility has driven their applications in diagnostics, therapeutics, and biosensing. This review examines the evolution from monomeric affibody constructs to multivalent supramolecular assemblies, highlighting how this shift overcomes key limitations while expanding functionality. Recent advances in conjugation chemistry, scaffold engineering, and protein design have enabled sophisticated affibody-based architectures with enhanced pharmacokinetic profiles and multivalent binding capabilities, thereby improving their utility in targeted drug delivery, molecular imaging, and theranostics. Full article

Zika virus (ZIKV) caused Zika outbreaks and continues to post threats to public health. ZIKV infection may cause congenital abnormalities during pregnancy and neurological manifestations in adults. The recurrent public health threat of Zika in various geographical areas demonstrates a need for the development of effective therapeutics. Currently, there are no approved therapies for Zika. ZIKV is a single-stranded, positive-sense RNA virus, whose genome encodes three structural proteins and seven non-structural proteins. The surface envelope (E) protein is essential for host–cell recognition and viral entry; therefore, inhibition of E-mediated viral entry is a key strategy underlying antiviral treatments. Here, molecular docking-based virtual screening was used to screen small-molecule compound libraries to identify potential ZIKV entry inhibitors. Among the compounds identified, Pyrimidine-Der1 exhibited efficient inhibition of reporter ZIKV infection. The microscale thermophoresis assay confirmed its binding with the ZIKV E protein. This compound has effective inhibition of authentic ZIKV infection in a plaque inhibition assay against R103451, PAN2016, and FLR human strains (IC₅₀: ~3–5 μM). Additionally, it efficiently inhibited ZIKV infection at viral entry and fusion steps of the virus life cycle in a time-of-addition assay. Overall, Pyrimidine-Der1 is a promising ZIKV entry inhibitor, warranting further optimization and evaluation. Full article

Background: Heat shock protein 90 (HSP90) is a molecular chaperone that stabilizes numerous oncogenic proteins and supports tumor survival. Small molecules targeting HSP90 offer a novel approach to overcome drug resistance and immune suppression in breast cancer. Methods: A novel thiazolyl benzodiazepine (TB) containing a hydrazone moiety was evaluated in breast cancer cell lines (ER⁺ MCF-7, TNBC MDA-MB-231, and HER2⁺ SK-BR-3). Cytotoxicity was assessed using the CCK-8 assay, followed by PCR sequencing, flow cytometry, RT-qPCR, protein profiling, and HSP90 binding assays. Results: TB showed the strongest activity in MCF-7 cells (IC₅₀ = 7.21 µM) compared to MDA-MB-231 (IC₅₀ = 28.07 µM) and SK-BR-3 (IC₅₀ = 12.8 µM) cells. Mechanistic studies showed that TB binds to HSP90 (Kd = 3.10 µM), leading to disruption of the oncogenic signal. TB induced G2/M cell cycle arrest, promoted apoptosis via Bax and Caspase-3 activation, and suppressed cancer stem cell markers (NANOG, OCT4, SOX2). Additionally, TB activated immune-related pathways via ERK/MAPK signaling and upregulated genes such as SMAD2, SMAD3, and JUN.Conclusions: TB functions as an HSP90 inhibitor with dual anticancer and immunomodulatory properties in Estrogen Receptor-Positive (ER⁺) breast cancer cells. These findings suggest that TB represents a promising scaffold for the development of multi-targeted breast cancer therapies. Full article

Plasma-activated water (PAW) is an emerging disinfectant; however, its potential as a quorum sensing inhibitor (QSI) for biofilm control remains underexplored, and its action mechanisms have not been elucidated. This study investigated the effects of PAW on biofilm formation and spoilage factors secretion in Pseudomonas fluorescens under sub-inhibitory conditions. PAW generated by treating water for 60 s (PAW-60) reduced biofilm biomass by up to 1.29 log CFU/mL after 12 h incubation. It also completely inhibited protease production (100%) and decreased siderophore production by 31.87%. N-butyryl-homoserine lactone (C₄-HSL) was identified as the dominant signaling molecule, with its production decreasing by 34.34–84.07% following PAW treatments. Meanwhile, C₄-HSL activity was significantly suppressed by 42.58–65.38%. An FTIR analysis revealed the formation of a new C=O group, indicating oxidative degradation of acyl homoserine lactones (AHLs). Exogenous C₄-HSL progressively restored the biofilm biomass, spoilage factors production, and QS-related gene expression levels, with no significant difference observed compared with the control at 0.05 µg/mL (p < 0.05). The results suggest that the inhibitory effects of PAW are primarily due to the disruption of AHLs transduction in the QS pathway. Molecular docking showed that the long-lived reactive species in PAW could bind to AHLs’ synthetic protein (FadD1) and receptor protein (LuxR) via hydrogen bonding. PAW-60 reduced the spoilage activity of P. fluorescens inoculated into fish muscle juice and extended its shelf life from 8 to 10 days during storage at 4 °C. A strong positive correlation was observed between AHLs accumulation and the spoilage process. These findings demonstrate that PAW mitigates biofilm formation and food spoilage by blocking signaling transduction, which involves suppression of AHLs production, oxidative degradation of AHLs molecules, and disruption of AHLs recognition. Full article

RNA triple helices are relatively understudied, including their interactions with small molecules. In this study, we evaluated eight previously reported triplex-binding molecules (TBMs) for their functional effects on the premature and mature MALAT1 triple helix. Based on UV thermal denaturation experiments, the TBMs berberine, coralyne, sanguinarine, berenil, and neomycin selectively stabilize the Hoogsteen interface of the MALAT1 triple helix. Moreover, fisetin, luteolin, and quercetin were more sensitive to nucleotide composition, whereas berberine, coralyne, sanguinarine, and berenil were more sensitive to changes in the length of the major-groove triple helix. Most TBMs could not outcompete MALAT1 triple helix-binding proteins, except for neomycin. Surface plasmon resonance experiments demonstrated that berberine and sanguinarine display relatively quick association and dissociation binding profiles. Treating human colorectal carcinoma cells with each of the TBMs reduced MALAT1 levels by ~20–60%. This study demonstrates that TBMs broadly recognize the premature and mature MALAT1 triple helix but exhibit subtle sensitivities, suggesting that TBMs can be designed to selectively bind triple helices based on nucleotide composition, length, and structural context. Full article

Background: Molecular mimicry contributes to the development of unwanted responses to self-antigens. Autoimmune phenomena have been observed in diseases caused by Aedes aegypti-transmitted arboviruses, but the occurrence of mimicry between salivary and human proteins has been unexplored. Methods: We used bioinformatic tools to determine if peptides from Aedes aegypti salivary proteins were present in the human proteome. We further characterized the potential of shared sequences to induce immunity by analyzing their predicted binding to MHC molecules and their occurrence in peptides from the Immune Epitope Database (IEDB). Results: We analyzed 9513 octapeptides from 29 Aedes aegypti salivary proteins against the human proteome and found 47 peptides identical to sequences from 52 human proteins, ranging in length from 8 to 18 amino acids. We found 302 matches of peptides predicted to bind with high affinity to MHC-I and MHC-II alleles associated with autoimmune diseases, and 14 human peptides containing shared sequences with Aedes aegypti salivary proteins validated as immunogenic in the IEDB. Conclusions: These results support the existence of molecular mimicry between Aedes aegypti salivary proteins and human antigens and provide a framework for studies to determine its contribution to responses directed to self-antigens in the context of arboviral infections. Full article

Background/Objectives: This review discusses the development and application of targeted protein degradation strategies, particularly focusing on the ubiquitin–proteasome pathway and PROteolysis-TArgeting Chimeras (PROTAC) technology, for antiviral therapies. Methods/Results: The synthesis of specific PROTACs exemplifies the potential of this approach to inhibit viral replication. The discussion also covers ongoing efforts to develop broad-spectrum antivirals and explores the limitations of small-molecule ligands, proposing antibody mimetics as a versatile alternative. The review details innovative strategies involving engineered antibody mimetics, termed ‘diving antibodies’ (DAbs), capable of intracellular delivery and targeting viral proteins within cells. These molecules are engineered using modular nanotransporters to facilitate intracellular delivery. The integration of E3 ligase-binding sites into DAbs enhances their capacity to induce targeted protein degradation, with experimental evidence supporting their efficacy. Conclusions: Overall, the review underscores the potential of combining targeted degradation technologies with innovative delivery systems to create effective antiviral therapies, especially for viruses with limited treatment options. Full article