Molecules
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Preprints posted in the last 30 days, ranked by how well they match Molecules's content profile, based on 37 papers previously published here. The average preprint has a 0.06% match score for this journal, so anything above that is already an above-average fit.
Kawabata, R.; Hagiwara, I.; Komizo, N.; Inaba, Y.; Matsui, T.; Ito, T.
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Catechinopyranocyanidins (Cpcs) which consist of diastereomers A and B are pigments derived from adzuki beans and are compounds in which the catechin and cyanidin skeletons are condensed to a pyrano ring. While catechins and anthocyanidins possess high antioxidant capacity, the physiological functions of Cpcs remains unclear. In this study, the antioxidant capacity of Cpcs was evaluated by in vitro antioxidant assays and by assessing their cytoprotective activity against oxidative stress in normal human dermal fibroblasts (NHDFs). Antioxidant capacity based on the hydrogen atom transfer (HAT) mechanism, as assessed by the ORAC assay revealed that Cpcs exhibit 14.1 mol TE/mol (Trolox equivalent antioxidant capacity: TEAC). Meanwhile, capacity based on the single electron transfer (SET) mechanism, as assessed by the DPPH, ABTS and CUPRAC assays revealed, they exhibit 2.1-3.6 mol TE/mol. Since TEAC value of Cpcs demonstrated by the HAT based mechanism higher than its SET based oxidative capacity suggesting that the antioxidant capacity of Cpcs is driven by the HAT mechanism. In cell culture experiments, Cpcs ameliorate cell toxicity in rotenone-induced injury model, suggesting to cytoprotective activity against mitochondrial dysfunction-dependent apoptosis. These results reveal novel physiological functions of Cpcs which may serve as a design guideline for elucidating in vivo dynamics based on antioxidant mechanisms.
Kedjar, Y.; Hognon, C.; Douki, T.; Dumont, E.; MONARI, A.
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The repair of photo-induced DNA lesions through nucleotide excision repair machinery is still the source of important questions. It has been observed that the repair rate of the different cyclobutane pyrimidine dimers, i.e. the photoproducts induced by dimerization of two {pi}-stacked pyrimidines (T<>T, T<>C, C<>T, C<>C), depends on the nucleobases involved in the lesion. TT derivatives (T<>T) are removed more slowly than those containing cytosine, especially in 5. Using all-atom molecular dynamics simulations and free-energy calculations, we demonstrate that the variation of the repair rate observed in human skin and in cultured cutaneous cell is associated to the recognition of the four lesions by the DDB2 protein moiety, and more specifically by the differential structural deformation induced on the complementary strand. Indeed, while C<>C and C<>T induce a larger deviation on the groove parameters, T<>T and T<>C, instead, affect DNA structure to a lesser extent. less affected. These effects then hamper differentially the downstream recruitment of the repair complexes. The observed DNA deformation correlates with the experimental repair rate and provides a structural rationale for the different repair rates of CPD by nucleotide excision repair machinery. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/724087v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@cf6b6dorg.highwire.dtl.DTLVardef@195e35forg.highwire.dtl.DTLVardef@1829296org.highwire.dtl.DTLVardef@165baba_HPS_FORMAT_FIGEXP M_FIG C_FIG
Behera, S.; Kungwani, N.; Mohanta, Y. K.
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Pseudomonas aeruginosa, a Gram-negative opportunistic pathogen is well known for life-threatening acute infections among the human population. The bacterium can withstand most antibiotics by using their high levels of inherent and acquired resistance mechanisms such as Biofilm-EPS, Persistence, and Quorum sensing (QS). Owing to the importance of adaptive antibiotic multi-drug resistance of P. aeruginosa, the current investigation is aimed to explore the phytochemicals derived from mangrove plants as potential agents to control biofilm and drug resistance mechanisms through a multi-mechanistic computational approach. For identifying potential compounds and target, In-silico drug repurposing technique is implemented by docking/virtual screening of 49 phytochemical compounds against 18 proteins involved in the Persister Cell formation, QS, and EPS synthesis in P. aeruginosa which resulted the proteins RelA and SpoT (persistence), PqsA, and PqSR (QS), and PelA and PelB (EPS synthesis) and compounds Taraxerone and Taraxerol to be potential. The results of docking were well corroborated with MD simulations. These targets and compounds explored through in-silico approach, are found to target potential antimicrobial pathways involving EPS synthesis, persistence genes, and QS, aiming to enhance antibiotic efficacy. Further, this study could be reference for in-vivo and in-vitro investigations to evaluate the further effectiveness of the compounds and potentiality of the proteins for MDR therapeutics of P. aeruginosa.
Dabkeviciute, G.; Celia, C.; Petrikaite, V.
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Glioblastoma (GBM) presents significant therapeutic challenges due to its aggressive nature, complex microenvironment and the limitations of conventional drug delivery systems. In this study, hybrid nanoparticles were developed by combining synthetic liposomes with macrophage-derived extracellular vesicles (EVs) to harness the strengths of both platforms. Two distinct liposomal formulations, DPPC:Chol:DSPE-mPEG2000 (F1) and DPPC:DPPS:Chol:DSPE-mPEG2000 (F2), were used as the basis for the synthesis. EVs derived from J774 macrophages were integrated with F1 and F2 to create hybrid nanoparticles (H-F1 and H-F2). Doxorubicin (DOX) was encapsulated using a pH gradient and a remote loading procedure. The mean particle size of H-F1-DOX and H-F2-DOX was 158.2 {+/-} 1 nm and 162.8 {+/-} 9 nm, respectively. The polydispersity index (PDI) was 0.130 {+/-} 0.012 and 0.084 {+/-} 0.033, while the zeta potential values were -14.9 {+/-} 0.7 mV and -26.7 {+/-} 3.1 mV, respectively. H-F2-DOX exhibited the highest encapsulation efficiency (EE%), reaching 76.5{+/-}3.4%. The encapsulated hybrids remained stable up to one week, at +5{degrees}C. The release of DOX from H-F2-DOX in DMEM supplemented with 10% serum showed pH sensitivity, with total DOX release of 64.9 {+/-} 5.3% at pH 7.4 and 90.7 {+/-} 6.5% at pH 5.5. The cell viability assay demonstrated that all formulations exhibited strong cytotoxic effects against GBM cells under normoxic conditions, with H-F2-DOX showing the most potent effect under hypoxia-mimetic conditions.
Dey, B.; Chatterjee, E.; Bansode, A.; Goel, B.; Jain, S. K.; Naik, P. K.; Guru, S. K.
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BackgroundTriple-negative breast cancer (TNBC) is an aggressive subtype lacking well-defined molecular targets, leaving chemotherapy as the primary treatment despite drug resistance, systemic toxicity, and high recurrence rates. Therefore, the development of effective and less toxic therapeutic agents is essential. This study investigated the anti-cancer potential of gloriosine, a bioactive alkaloid with antiproliferative activity and low toxicity toward normal breast cells. MethodsPotential targets of gloriosine were predicted using SwissTargetPrediction, TargetNet, and PharmMapper, and overlapping genes related to TNBC and glutamine metabolism were selected. Protein-protein interaction networks, Gene Ontology, and KEGG pathway enrichment analyses were performed. Molecular docking evaluated binding affinity, followed by in vitro validation using cell viability, colony formation, and wound healing assays. ROS levels were measured by DCFDA and GSH assays, and ferroptosis was assessed by Western blot and FerroOrange staining in MDA{square}MB{square}231 cells. ResultsA total of 100 potential targets were identified, with 60 overlapping with TNBC and glutamine metabolism-related genes. Key targets included SRC, EGFR, mTOR, and HSP90AA1. Enrichment analyses indicated involvement in cancer progression, metabolic regulation, and resistance pathways, including central carbon metabolism, EGFR inhibitor resistance, and ErbB signaling. Gloriosine showed strong binding affinity toward hub targets. Experimental studies confirmed concentration-dependent inhibition of cell proliferation and migration. Mechanistically, gloriosine suppressed glutamine metabolism via GLS1 downregulation and induced ferroptosis, evidenced by increased ROS, glutathione depletion, GPX4 downregulation, and elevated intracellular iron levels. ConclusionsGloriosine exerts significant anti-cancer effects in TNBC through multi-target modulation and induction of ferroptosis, highlighting its potential as a promising therapeutic candidate. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/725321v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@ce0ebcorg.highwire.dtl.DTLVardef@29603borg.highwire.dtl.DTLVardef@6d0025org.highwire.dtl.DTLVardef@249700_HPS_FORMAT_FIGEXP M_FIG C_FIG Flow chart of the network pharmacological and in vitro study of gloriosine
Faleel, D.; Arnest, R.; Aradhyula, V.; Boyapalli, S.; Haller, S. T.; Kennedy, D. J.
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The Na+/K+-ATPase (NKA) regulates ion balance in the kidney and influences cellular processes like proliferation and apoptosis through its signal transduction. The endogenous ligand 20-Hydroxyeicosatetraenoic acid (20-HETE) contributes to inflammation and fibrosis in chronic kidney disease (CKD) and inhibits NKA activity in renal tubules. However, the molecular mechanism of this interaction remains unclear. In this study, we used in-silico approach to investigate the potential interaction between 20-HETE and NKA. Various ligands, including known NKA ligands such as cardiotonic steroids (CTS), 20-HETE, and negative controls, were docked using rigid and Induced Fit Docking to predict the affinity of the ligands toward NKA. Binding free energy calculations with the Prime Molecular mechanics with generalized Born and surface area (Prime MM/GBSA) tools were used to confirm the involvement of key amino acids in ligand-receptor interactions. The docking analyses revealed that 20-HETE exhibited a binding affinity comparable to negative control, with some differences between rigid and induced fit docking. Binding free energy data highlighted key amino acids in the 20-HETE and NKA interaction. Interaction fingerprint and mutations such as Ala330Gly and Val329Ala significantly reduced binding free energy, while Thr804Ala showed a notable decrease, underscoring the potential importance of these amino acids in ligand stabilization. These findings provide computational evidence supporting potential direct interaction between 20-HETE and NKA and identify candidate residues for future experimental validation.
Tang, B.; Lee, H.-O.; Krzikike, D.; Gupta, S.; Cai, K. Q.; kruger, w. D.
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BackgroundHomozygous deletion of the methylthioadenosine phosphorylase (MTAP) gene is a frequent genetic alteration in cancer. MTAP, which creates adenine from 5-methylthioadenosine (MTA), is constitutively expressed in all tissues throughout the body. Previously, we described a novel strategy to specifically target MTAP-deleted cancer cells by combining the antipurine prodrug 2-fluoroadenine (2FA) with MTA. In vitro, this combination efficiently killed MTAP- cancer cells, but in vivo the combination was much less effective in vivo. Here, we explored the role of xanthine oxidase (XO) in this process. Materials and MethodsVarious combinations of 2FA, MTA, and the xanthine oxidase inhibitor febuxostat (FX) were tested in various cancer cell lines grown in vitro and in mice. LC-MS/MS was used to examine the levels and ratio of intracellular 2-FA-containing nucleotides compared to adenine-containing nucleotides. Results and conclusionsThe treatment of cells with 2FA+MTA in vitro resulted in much higher 2FANP/ANP ratios than the same treatment in vivo. The addition of XO to culture media in vitro effectively abolished the killing by 2FA, and this effect was fully reversed by the addition of febuxostat (FX), a xanthine oxidase inhibitor. In vivo, the addition of FX to 2FA results in increased cell killing and toxicity and a 1000% increase in the amount of 2FA converted to 2-FA-monophosphate (2FAMP). Xenograft studies using MTAP- HT1080 and MiaPaCa-2 cell lines have shown that a 2FA/MTA/FX cocktail can cause tumor regression in vivo. These studies suggest that the combination of 2FA/MTA/FX should be explored as a treatment for MTAP- cancer.
Rehan, S. S.; Kiran, A.; Yasmeen, G.; Altaf, A.; Maqbool, M. T.; Hadi, F.; Aftab, S.
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Freshwater algae represent an underexplored source of naturally occurring bioactive metabolites with potential applications in pharmaceutical and biomedical research. This study investigated the phytochemical composition, antioxidant capacity, and preliminary cytotoxic potential of ethanolic and n-hexane extracts of freshwater algal species collected at Jilani Park, Lahore, Pakistan. Algal species were identified morphologically by Dr. Ghazal Yasmeen (Institute of Botany, Punjab University, Lahore). Extracts were analyzed using gas chromatography-mass spectrometry (GC-MS) and qualitative phytochemical screening. Antioxidant activity was evaluated using DPPH radical scavenging, hydrogen peroxide scavenging, and reducing power assays. Cytotoxic potential was assessed using MTT and cell adhesion assays on HeLa and SF767 cell lines as preliminary indicators of bioactivity. GC-MS analysis identified 25 compounds, including sterols, fatty acid esters, terpenoids, phenolic compounds, and volatile metabolites. Phytochemical screening confirmed the presence of flavonoids, phenolics, tannins, and terpenoids in the extracts. Among the tested extracts, the n-hexane fraction demonstrated comparatively higher antioxidant activity across multiple assays. Ethanolic extracts showed moderate reductions in HeLa cell viability, whereas limited effects were observed in SF767 cells. These findings suggest that freshwater algae are promising natural reservoirs of antioxidant metabolites with potential relevance for future isolation and characterization of bioactive compounds for biomedical applications. Further purification and mechanistic studies are required to identify specific active constituents.
Brink, D. F.; Sapp, T. L.; Ghafoor, T. S.; Boyland, P. A.; Tamazawa, Y. C.; Kaur, G.; Shults, N. V.; Sullivan, R. D.; Suzuki, Y. J.
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Rhodiola rosea is a traditional medicinal plant often classified as an adaptogen, with reported effects in supporting the bodys response to physical, environmental, and emotional stressors. The present study investigated the antioxidant properties of Rhodiola rosea extract and its major chemical constituents to provide insight into their potential mechanisms of action. Through in vitro biochemical assays, we demonstrated that Rhodiola rosea extract has the capacity to reduce hydrogen peroxide (H2O2) levels. Among its primary chemical components, rosavin significantly decreased H2O2, whereas salidroside had no effect. Neither compound affected superoxide levels. Structural analysis revealed that the intact phenylpropanoid glycoside architecture of rosavin is required for activity, as its individual components, arabinose and rosin, showed no inhibitory effect. Further investigation demonstrated that rosavin attenuates H2O2-mediated oxidation of thiol groups, supporting a role in cellular redox regulation. In cultured human cells, rosavin mitigated reductions in cell viability induced by exposure to H2O2, indicating cytoprotective effects under oxidative stress conditions. Finally, in an in vivo model, administration of SARS-CoV-2 spike protein increased circulating levels of H2O2, which were subsequently reduced following rosavin treatment. Collectively, these findings identify rosavin as a structurally dependent antioxidant component of Rhodiola rosea that modulates H2O2-associated oxidative stress and supports further investigation of phenylpropanoid glycosides as adaptogens.
Vu, B. L.; Lam, H.; Nguyen, L. D. L.; Do, C. P.; Trang, V. T. H.
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The chemical constituents and cytoprotective potential of Cyathea podophylla, a Vietnamese fern, remain poorly investigated. This study aimed to isolate its compounds and evaluate their in vitro cytoprotective activity against 6-hydroxydopamine (6-OHDA)-induced toxicity in F11 cells. Compounds were chromatographically isolated and structurally characterized using NMR and HR-ESI-MS. Seven compounds were identified: five phenolics (trans-cinnamic acid, (E)-4-(3,4-dihydroxyphenyl)but-3-en-2-one, p-coumaric acid, 3,4-dihydroxybenzoic acid, 4-O-acetyl-caffeic acid), 5-hydroxymethylfurfural, and butyl-{beta}-D-fructofuranoside. Six of these are newly reported for the Cyathea genus. In MTT assays, butyl-{beta}-D-fructofuranoside exhibited the strongest cytoprotective effect (69.6% cell protection at 10 {micro}M, p < 0.001), followed by (E)-4-(3,4-dihydroxyphenyl)but-3-en-2-one (39.2% at 10 {micro}M). The remaining compounds lacked significant activity. These findings expand the phytochemical profile of Cyathea podophylla and provide preliminary evidence of its cytoprotective properties against 6-OHDA-induced injury, warranting further mechanistic and in vivo validation.
Sottorff, I.
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Biological metal chelators are of great interest for investigation due to their capacity to retain or mobilize metals from the environment. While some biological and bioinspired chelators find use in medical applications, others are promising platforms for the mining or recycling of technologically important metal ions. In particular, the siderophores, which are primarily iron chelators, have been studied. Four siderophores of relevance are schizokinen and its derivatives, which have been isolated from bacterial and algae cultures, in addition to soil. These siderophores have shown metal chelating activity with different metals such as iron, copper, and aluminum. In the time of metabolomics, it is required to unambiguously determine the identity of the produced siderophores as quickly as possible. Thus, Liquid Chromatography coupled to High Resolution Mass Spectrometry and mass-tandem fragmentation (LC-HRMS-MS) provides a quick and applicable alternative for identification of schizokinen and its derivatives. Here, we report an analytical method for the identification and potential quantification of the schizokinen siderophore series. We developed a working method through LC-HRMS-MS, which provides the unequivocal identification of the four schizokinen derivatives, which has not been reported to date. Additionally, we constructed the molecular network for the four molecules to enable their identification using the Global Natural Products Social Molecular Networking (GNPS) platform. Most importantly, this contribution can help speed up the characterization of schizokinen producers and facilitate the dereplication process of siderophores.
Cisterna Garcia, A.; Gonzalez Lopez, A. M.; Vozi, A.; Esteban, M. A.; Egli, A.; Jutzeler, C.; Palma, J.; Sanchez-Ferrer, A.; Botia, J. A.
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Antimicrobial resistance (AMR) has a profound impact on animal and human health and is associated with substantial morbidity, mortality and public health costs. There is a clear need to develop novel, effective antibiotic agents, which can overcome the current AMR crisis. Antimicrobial peptides (AMPs) may offer such a solution and have attracted growing attention for their potential to combat AMR. In parallel, the growing availability of peptide sequences in public databases has stimulated the development of numerous machine learning and deep learning tools to predict antimicrobial activity computationally. However, it remains unclear how reliably these tools can be compared, as existing studies often rely on heterogeneous datasets and inconsistent evaluation protocols that may lead to data leakage and inflated performance estimates. This raises a central question: what evaluation criteria and benchmark resources are needed to enable fair, reproducible, and biologically meaningful assessment of AMP prediction tools? We address this question by focusing specifically on antibacterial peptides (ABPs). We first provide an overview of AMP databases relevant to antibacterial activity and compare their content, redundancy, and experimental metadata. We then critically assess existing computational tools for ABP prediction, highlighting key limitations related to dataset construction, affinity to certain sequences, data leakage, and inconsistent performance reporting. Based on these limitations, we propose a reference evaluation framework designed to improve comparability, reproducibility, and practical utility in ABP prediction. Finally, we provide targeted recommendations for AMP databases and future tool development to support more robust progress in the computational discovery of ABPs.
Sakai, H.; Chung, M. H.; Nakaya, T.; Ohbuchi, K.; Isobe, Y.; Arita, M.; Tsumagari, K.; Imami, K.; Hirokawa, T.; Tsugawa, H.
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Glycyrrhiza uralensis is a widely used medicinal plant present in more than 70% of Kampo formulations in Japan owing to its diverse pharmacological activities, including immunomodulatory, antitumor, and antioxidant effects. Isoliquiritigenin (ILG), a major chalcone constituent of G. uralensis, exhibits anti-inflammatory activity; however, its molecular mechanism remains unclear. Here, we employed an activity-based protein profiling approach to identify the molecular targets of ILG. Given that the ,{beta}-unsaturated carbonyl moiety of ILG can covalently react with reactive cysteine residues via nucleophilic addition, we used an iodoacetamide-based probe to globally profile cysteine-reactive proteomes. The comparative analysis between ILG- and vehicle-treated RAW 264.7 macrophages identified cysteine 65 (Cys65) of lipocalin-type prostaglandin D2 synthase (L-PGDS) as a potential covalent target. ILG treatment did not alter L-PGDS expression levels, indicating that reduced probe labeling reflects direct covalent competition rather than changes in expression. Consistently, ILG significantly suppressed prostaglandin D2 (PGD2) production, comparable to the selective L-PGDS inhibitor AT-56. Although both ILG and AT-56 reduced interleukin-6 expression, ILG exerted a stronger inhibitory effect. Our results demonstrate that covalent inhibition of L-PGDS and subsequent suppression of PGD2 production represent a key mechanism underlying the anti-inflammatory activity of ILG.
XU, T.; Guo, Z.; Khan, K. S.; Huang, Y.; Ma, B.; Liu, J.; Felsher, D. W.; Ng, B. W.-L.
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c-Myc is a transcription factor that drives tumorigenesis in many cancers. It is notoriously difficult to directly target c-Myc, mainly due to its lack of well-defined druggable pockets. O-linked {beta}-N-acetylglucosamine modification (O-GlcNAcylation) is a post-translational modification (PTM) playing an important role in regulating c-Myc functions in cancer. However, previous studies have primarily relied on global perturbations to investigate c-Myc O-GlcNAcylation, making it difficult to determine its direct functional consequences due to concurrent cellular effects. Here, we report a bifunctional O-GlcNAcylation TArgeting Chimera (OGTAC) molecule, which can induce the proximity of c-Myc and O-GlcNAc transferase (OGT) in living cells, thereby enhancing the O-GlcNAcylation of c-Myc. The c-Myc-targeting OGTAC exhibits anti-proliferation effect against cancer cells. Mapping of c-Myc occupancy on genome indicates that OGTAC rewires c-Myc transcriptional activity and reprograms expression of the downstream oncogene MALAT1, in an O-GlcNAcylation-dependent manner. Overall, OGTAC presents a novel chemically induced proximity (CIP)-based tool to target and rewire c-Myc activity in cancer. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=135 SRC="FIGDIR/small/722559v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@d1c640org.highwire.dtl.DTLVardef@2eb70corg.highwire.dtl.DTLVardef@f38970org.highwire.dtl.DTLVardef@c421c8_HPS_FORMAT_FIGEXP M_FIG C_FIG
Xu, X.; Mailhot, O.; Correy, G. J.; Huang, X.; Braz, J.; Shi, D.; Srinivasan, K.; Zielinski, K.; Holota, Y.; Kuziv, Y.; Tsoutsouvas, C.; Levinzon, N.; Doruk, Y. U.; Rachman, M.; Diolaiti, M.; Stevens, M.; Liu, F.; Holland, K.; Hubner, H.; Wang, J.; Wu, Y.; Ashworth, A.; Makriyannis, A.; Zhang, Y.; Moroz, Y.; Gmeiner, P.; Abel, R.; Manglik, A.; Basbaum, A. I.; Roth, B. L.; Fraser, J. S.; Shoichet, B. K.
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Ligand optimization is central to drug discovery as hundreds of analogs might be designed and synthesized between an initial hit and a therapeutic candidate. The efficiency of this process is unclear, at least partly because there is no random background for optimization against which to compare. Such a random background might emerge from synthetically accessible but otherwise systematic random small substitutions across starting ligands, measuring likelihood of achieving a substantial improvement in affinity/potency or other property by any single perturbation. Recent literature and ligand-affinity/potency databases suggest that perhaps 10% of analogs with minor modifications improve upon a parents potency substantially (by [≥]10-fold), but this number is clouded by reporting bias, intentional improvement, and inter-group reproducibility. To begin to establish a background expectation for ligand optimization, we comprehensively and systematically modified 18 lead molecules across six targets with single atom changes; 257 compounds were synthesized. Unexpectedly, 11.2% of these random small perturbation analogs improved potency by [≥]10-fold over their parents. Conversely, these more potent analogs typically had worse in vitro pharmacokinetics (e.g. reduced metabolic stability, lower plasma free fraction). While it was possible to find analogs where the potency increase compensated for inferior exposure and half-life, resulting in more potent compounds in vivo, overall a frustrated landscape for ligand optimization is revealed. This study begins to establish a background expectation for ligand potency optimization and offers a simple strategy to do so. It also begins to quantify the challenges confronting the field in moving beyond in vitro potency.
Dudek, A.; Janapatla, R. P.; Chen, C. L.; Chiu, C. H.
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Fucoidans have been widely reported to show SARS-CoV-2 antiviral activity. In this study, we observed a striking difference in the inhibitory potency between two commercially available fucoidans: Fucus vesiculosus crude (Fvc) and pure (Fvp). SEC-MALS analysis revealed two molecular weight populations for Fvc (1098 kDa, 58.58 kDa) and one for Fvp (40.48 kDa). At micromolar concentrations of fucoidans, the binding affinities (KDs) of Fvc_1098 (223 nM) and Fvc_58 (4.27 {micro}M) for the amine-biotinylated SARS-CoV-2 receptor binding domain (RBD) were higher than that of Fvp (76.5 {micro}M). At nanomolar concentrations, binding was observed only to the Avi-tag-, but not amine-biotinylated RBDs, suggesting better accessibility of their binding sites. The association rates (kon) were faster for Fvc than for Fvp. Similarly, affinities of Fvc_1098 (23.4 nM) and Fvc_58 (4.48 M) for ACE2 were greater than that of Fvp (66.8 M), indicating that Fvc can bind directly to both RBD and ACE2. Fvc demonstrated enhanced inhibitory potency (IC50 = 58 g/mL) compared to Fvp (IC50 > 239 g/mL) in the pseudovirus entry assay and did not induce cytotoxicity in HEK293T cells. In conclusion, crude fucoidan with high fucose content and high molecular weight shows promising antiviral activity.
Ferreyra, S.; Dutra, I.; Galeano, A.; Paccanaro, A.
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Drug-target affinity (DTA) prediction is a key task in drug discovery, enabling the estimation of the interaction strength between candidate compounds and biological targets. However, current models rely on connectivity-based molecular representations and do not explicitly account for the spatial organization, also known as stereochemistry. This limitation becomes evident when considering chirality, where a drug can exist as enantiomers, i.e., molecules that share the same atoms and bonds but differ in their three-dimensional arrangement. Despite their chemical similarity, they can interact differently with the same target, leading to variations in binding affinity and biological activity. In this paper, we propose a stereochemistry-aware DTA prediction framework that incorporates this information into molecular representations. Drug representations are learned from chemical structure using a directed-bond message passing graph neural network that captures enantiomers configurations, while protein targets are represented through sequence-based embeddings. Experiments on the Davis dataset demonstrate that our model can improve affinity prediction. Importantly, a case study on a manually curated dataset of enantiomers with different biological action shows that the model is able to distinguish the affinities in the two forms consistent with their experimentally observed biological activity. These findings support the relevance of stereochemistry-aware molecular representation for more accurate and chemically faithful DTA prediction.
Baeumer, L.; Stal Papini, F.; Zettner, N.; Sawas, S.; Roth, C.
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The gut microbiome plays a central role in host metabolism, immune function, and overall health, with disruptions in microbial composition (dysbiosis) being associated with a range of metabolic, inflammatory, and infectious conditions [1,2]. Consequently, strategies aiming to modulate the microbiome require selective activity that preserves beneficial commensals while limiting pathogenic organisms [3]. In this context, ThymoQuin(R)--a cold-pressed, standardized black cumin (Nigella sativa) seed oil developed by TriNutra Ltd. and defined by [≥]3% thymoquinone (TQ), controlled p-cymene levels, and low free fatty acids ([≤]1.25%)--was evaluated for its microbiome-relevant activity. In vitro minimum bactericidal concentration (MBC) assays across three independent batches demonstrated a biphasic, dose-dependent response. At intermediate concentrations (0.25-0.5%), Streptococcus thermophilus was strongly stimulated (up to 53-fold) and Lactiplantibacillus plantarum fully preserved, while Klebsiella pneumoniae was effectively reduced (>94%). Akkermansia muciniphila exhibited stable viability at concentrations below 1%, with reductions only observed at 1%. This is notable given its role as a mucin-degrading commensal that has been linked to metabolic health, but whose abundance may vary across physiological and disease contexts [4,5]. At concentrations [≥]1%, selective effects diminished, resulting in broader antimicrobial activity and reduced specificity. These findings indicate a defined concentration range in which selective microbiome modulation is maintained, whereas higher thymoquinone levels may increase the risk of non-selective detrimental effect on microbes.
Pawar, P.; samarasinghe, s.
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Tuberculosis (TB) remains a formidable global health challenge, exacerbated by the emergence of drug-resistant Mycobacterium tuberculosis strains that threaten to render existing drug therapies and vaccine ineffective. Despite the availability of the Bacillus Calmette-Guerin (BCG) vaccine, its limited efficacy--primarily in infants and young children--falls short of reducing TB prevalence or offering adequate protection to adults. Therefore, developing a new TB vaccine with enhanced efficacy and the capability to generate a robust reservoir of memory cells is essential. Addressing the challenge of drug-resistant tuberculosis requires a deep understanding of bacterial evolution and developing robust countermeasures. This study aims to design a next-generation TB vaccine that provides broad-spectrum protection against various Mycobacterium tuberculosis strains, including drug-resistant ones. By conducting an in-depth investigation into pathogen-human interactions, the research proposes a holistic framework that leverages computational vaccinology to tackle challenges posed by pathogen polymorphism and overcome the limitations of conventional vaccines. By targeting conserved proteins across diverse TB strains and enhancing both humoral and cell-mediated immunity, this study proposes a new strategy for an epitope-based vaccine that provides long-lasting, universal coverage. An extensive proteomic, reverse vaccinology and immunoinformatics analysis of 159 TB strains yielded 27 highly conserved, immunogenic, non-toxic, and non-allergenic epitopes. These epitopes, consisting of 14-cytotoxic T-lymphocytes (CTL), 5-helper T-lymphocytes (HTL), and 8-B-cell epitopes, were used to construct a three-dimensional, multi-epitope TB vaccine designed based on a new concept introduced in this research for maximising vaccine efficacy. Molecular docking and immune simulation studies demonstrated a significant affinity between the vaccine constructs and toll-like receptors, indicating a strong potential for effective immune system engagement. The crucial features of the epitope-based TB vaccine constructed in this research include sequence conservancy, robust antigenicity, exclusion of self-peptides and potential for diverse allelic interactions. The proposed epitope-based vaccine is poised to be highly effective, safe, and capable of providing universal coverage, potentially paving the way for global TB eradication. Validation in laboratory and clinical settings will be essential to confirm its efficacy and real-world applicability.
Yankson, G.; Awortwe, K. Y.; Chama, M. A.; Paemka, L.
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BackgroundDichapetalin M (Dic M), an active compound extracted from medicinal plants in the Dichapetalum genus, has been previously shown to possess anti-proliferative activity against cancer cell lines. However, the specific mechanism through which it exerts its anticancer effects remains unknown. PurposeThis study focused on elucidating the mechanism of action of dichapetalin M to further explore its potential as a therapeutic agent for resistant and metastatic breast cancer. MethodWe confirmed the Estrogen Receptor (ER) as a target of Dic M, using an in vitro approach. Furthermore, we examined both the apoptotic and migrastatic effects of dichapetalin M by assessing its impact on the expression of key apoptosis-related and cancer cell migration genes. Finally, we evaluated the compounds effect on Multi-drug Resistance Gene MDR1 expression, a gene linked to cancer drug resistance. ResultsOur target validation experiments demonstrated that Dic M exhibited considerably higher cytotoxicity in ER-positive breast cell lines compared to ER-negative cell lines. Furthermore, treatment of MCF-7 cells (which are ER-positive) with Dic M led to a dose-dependent increase in AREG (amphiregulin), a downstream effector of the Estrogen Receptor. Additionally, Dic M inhibited actin polymerization and significantly downregulated genes involved in the turnover of actin monomers. Scratch-wound assay results further demonstrate that Dic M reduces the rate of cell migration, although its impact on EMT-related gene expression was only observed at high doses. Additionally, Dic M treatment in MCF-7 cells resulted in a significant decrease in the expression of pro-apoptotic genes and MDR1 expression. ConclusionsThese findings indicate that Dic M likely interacts with the Estrogen Receptor and employs the apoptotic pathway to exert its cytotoxic and anti-proliferative effects. Dic M exhibits promising potential, such as anti-migrastatic properties and downregulation of a key breast cancer resistance gene, warranting further investigation.