Search Results (99)

Papain-like cysteine proteases (PLCPs) are vital enzymes involved in plant development, acting as key regulators of processes such as seed germination, nutrient mobilization, senescence, and programmed cell death. In the present study, we analyzed active PLCPs in various barley organs, including roots, leaves, stems, and seeds at different stages of plant development. Protein extracts obtained from barley samples (4-day-old seedlings; plants at 2, 4, 7, and 11 weeks after sowing; developing seeds from 11-week-old plants; and mature dry seeds) were subjected to anion-exchange chromatography. Fractions containing active PLCPs were pooled, biotinylated using the DCG-04 probe, affinity-purified using streptavidin-agarose, and subsequently analyzed via SDS-PAGE. Bands corresponding to biotinylated PLCPs (detected using streptavidin-peroxidase and a chemiluminescent substrate) were excised from the gel and analyzed by tandem mass spectrometry, enabling the identification of up to 23 distinct PLCPs belonging to nine known PLCP subfamilies. Among the identified PLCPs, HvPap-6 from the L-like D subfamily proved to be the most abundant across all barley samples. In seedlings, B-like and L-like D proteases constituted the largest proportion of all PLCP classes, and their levels continued to increase as the plants developed. Although the relative abundance of L-like B and L-like C proteases was high in seedlings, their levels declined in the roots and leaves of developing plants, as three PLCPs from the L-like B subfamily were identified only during the seedling stage. These results suggest that L-like B and L-like C proteases play an important role in seed germination and seedling development. Organ-specific expression was also observed for certain PLCPs: HvPap-26 from the L-Like C subfamily was identified only in the shoots and roots of seedlings; four PLCPs of the L-like E subfamily were detected solely in the roots, whereas two other proteases from this subfamily were identified exclusively in the leaves and shoots under our experimental conditions. Thus, our results suggest that certain active PLCPs are organ-specific, and that the relative importance of identified PLCPs varies within these organs during plant development. Full article

Background/Objectives: The escalating crisis of antibiotic resistance and the inherent limitations of conventional antibiotics necessitate the development of innovative therapeutic strategies. Targeted drug delivery (TDD) offers a powerful approach to enhance efficacy, minimize systemic toxicity, and circumvent bacterial resistance. This systematic review aims to evaluate the potential of unique bacterial transport systems (BTSs), surface specific receptors and intracellular enzymes as platforms for TDD via the “Trojan Horse” strategy (THS). Methods: A comprehensive literature review was conducted, focusing on studies that investigated the specificity and mechanisms of BTSs responsible for the uptake of metabolites that are essential for and unique to bacteria. This includes an analysis of transport systems for siderophores, bacteria-specific sugars, cell wall components, D-amino acids, and vitamins. We assessed preclinical and clinical examples of drug conjugates utilizing these pathways, as well as emerging platforms such as bacteriophage-derived proteins, antibody–antibiotic conjugates, and bacterial extracellular vesicles (EVs). Results: BTSs demonstrate high specificity for their cognate substrates, providing effective molecular gateways for TDD of drugs photosensitizers and diagnostic probes in form of conjugates. The siderophore–cephalosporin conjugate cefiderocol represents a clinically validated example, having received FDA approval. Preclinical studies further reveal that conjugates utilizing sugars (e.g., maltose, trehalose) and vitamins (e.g., B12) can significantly enhance antibiotic uptake and activity against both Gram-positive and Gram-negative pathogens, including drug-resistant strains. Emerging platforms like bacteriophage endolysins and engineered EVs show promise for overcoming biological barriers such as bacterial outer membranes and intracellular host niches. Conclusions: The THS leveraging BTSs represents a clinically viable and promising avenue for next-generation antibacterial therapies. Advantages of BTS include overcoming bacterial resistance, such as reduced membrane permeability and efflux pumps, enabling the “revival” of antibiotics that are poorly permeable or toxic, increasing their local concentration at the target site and reducing side effects on host cells. While significant progress has been made, a striking disconnect persists between the hundreds of conjugates demonstrating potent in vitro activity and the limited agent that has achieved clinical use. This in vitro–in vivo gap reflects, in large part, the early stage of this field rather than a fundamental failure. Further research is critically needed not only to identify novel BTSs and optimize drug-linker chemistry, but also to systematically address the translational barriers—including poor pharmacokinetics, immunogenicity, and unexpected toxicity—that have prevented most promising candidates from advancing beyond preclinical evaluation. Full article

Background/Objectives: The clinical management of bladder cancer is severely impeded by high recurrence rates and the rapid emergence of chemoresistance, necessitating the discovery of novel therapeutic agents with distinct mechanisms of action. Dehydrodiisoeugenol (DHE), a bioactive neolignan, exhibits potent anti-tumor efficacy, yet its direct molecular targets and mode of action remain elusive. Methods: To deconvolute the mechanism of DHE, we integrated a phenotypic screening approach using 2D cell lines and 3D patient-derived organoids with a chemoproteomics-based activity-based protein profiling (ABPP) strategy. We synthesized a functionalized photoaffinity probe to capture the specific interactome of DHE under physiological conditions and validated targets via cellular thermal shift assays (CETSA), quantitative mass spectrometry, and 100 ns molecular dynamics (MD) simulations. Results: DHE exhibited potent dose-dependent cytotoxicity in bladder cancer cells, with IC50 values of 39.23 μM in T24 and 34.58 μM in 5637 cells. In 3D patient-derived organoids, DHE significantly reduced viability (p < 0.0001). Using a dual-filtering ABPP strategy, we identified 65 high-confidence candidate targets, prioritizing PTPN1 (PTP1B) as the primary functional interactor. Comparative molecular docking and 100 ns MD analyses showed that multiple stereoisomers of DHE could adopt plausible PTPN1-binding modes. Mechanistically, organoid proteomics indicated that DHE engagement with PTPN1 disrupts ER membrane homeostasis, thereby modulating the PI3K-Akt signaling axes. Conclusions: These findings establish PTPN1 as a critical druggable vulnerability in bladder cancer and define the molecular basis for the therapeutic potential of DHE. This study highlights the power of combining chemoproteomics with physiological 3D models to accelerate the translation of natural products into precision cancer therapies. Full article

Background/Objectives: T-cell lymphomas are relatively common in veterinary species, yet current diagnostic tools such as PCR-based clonality assays often lack sensitivity and specificity. In humans, we recently developed two related tissue-based diagnostic approaches based on the differential detection of the mutually exclusively expressed TCRbeta1 and 2 (TCRβ1 and 2) constant region proteins, or the corresponding TRBC1 and TRBC2 transcripts. Analogous to the detection of kappa/lambda light chains for the diagnosis of B-cell/plasma cell neoplasms in human clinical practice, our TCRβ1/2 diagnostic assay has the potential to transform veterinary diagnostic workflows. Methods: We identified and confirmed the sequences of the relevant TRBC1 and TRBC2 sequences in both cats and dogs, focusing on the 3′ untranslated region (UTR), where there is the least sequence homology between TRBC1 and TRBC2. To allow us to design appropriate probe sequences, we confirmed a lack of 3′UTR in either species, and we observed limited 3′ untranslated region UTR sequence polymorphism in the cat but not in the dog 3′UTR. We designed BaseScope™ RNA in situ hybridization probes targeting the 3′ UTR to distinguish between TRBC1 and TRBC2 transcripts in formalin-fixed paraffin-embedded tissues. Results: In normal tissues, we found the TRBC2:TRBC1 expression ratio to be similar to the 1.2:1 ratio in humans, between 1:1 and 3:1, skewing towards TRBC2, in both dogs and cats. These findings were corroborated using quantitative reverse transcription PCR. Applying our in situ hybridization probes to cases of T-cell lymphoma in dogs and cats, we demonstrated that an assay for differential expression of TRBC1 and TRBC2 in T-cell populations could identify clonal T-cell populations, as in human diagnostics. If further studies corroborate this proof-of-concept study, TRBC1/2 detection could obviate the need for slow, complex and expensive multiplexed PCR-based (PCR for antigen receptor rearrangements (PARR)) clonality assays. Conclusions: This study provides proof-of-concept data for a novel diagnostic approach that could simplify and substantially improve the accuracy of lymphoma diagnostics in veterinary medicine, by detecting TRBC1/2 transcripts. Full article

Mild cognitive impairment (MCI) represents an intermediate stage between normal aging and Alzheimer’s disease. This study investigated the neuroprotective effects of a combined extract of Mentha piperita (MP) and Cornus officinalis (CO) (MC) using in vitro and in vivo models. In SK-N-SH cells, pretreatment with MC (50–150 μg/mL) significantly attenuated H₂O₂-induced cellular injury, as evidenced by a reduction in Annexin V-positive cells and an increase in brain-derived neurotrophic factor (BDNF) mRNA expression. Rosmarinic acid and loganin, the marker compounds of MP and CO, alone or combined at a 6:4 ratio, mitigated H₂O₂-induced decreases in cell viability and BDNF mRNA. In the in vivo study, male Sprague–Dawley rats were orally administered MC (50, 100, or 200 mg/kg/day) for 28 days, with phosphatidylserine (50 mg/kg/day) serving as a positive control. MC administration significantly improved cognitive performance in rats with scopolamine-induced memory impairment, as demonstrated by increased step-through latency in the passive avoidance test and reduced escape latency in the Morris water maze. Furthermore, in the probe trial, MC-treated rats spent significantly more time in the target quadrant, indicating enhanced spatial memory retention. Mechanistically, MC restored hippocampal acetylcholine levels and reversed the scopolamine-induced decrease in BDNF and its downstream signaling. Specifically, MC upregulated hippocampal BDNF expression and enhanced the phosphorylation of extracellular signal-regulated kinase (ERK), protein kinase B (AKT), and cAMP response element-binding protein (CREB). In conclusion, these results demonstrate that the MC extract possesses potent neuroprotective and learning- and memory-enhancing effects, highlighting its potential as a therapeutic candidate for managing age-related cognitive decline and MCI. Full article

Tuberculosis, caused by Mycobacterium tuberculosis, remains a global health challenge, particularly due to multidrug-resistant strains. Photodynamic therapy using porphyrin-based photosensitizers offers a promising alternative by targeting the trehalose-rich cell wall of the bacillus. Motivated by prior experimental observations that shorter linkers improve efficacy, this study probes the molecular basis of linker-length-dependent activity in trehalose–porphyrin glycoconjugates. Here, we show that shorter linker lengths are consistent with improved activity in vitro and, in an Ag85B docking model, constrain conformational flexibility, reduce solvent exposure, and promote tighter packing consistent with stronger predicted interactions. Using computational docking, we analyzed binding scores, RMSD variability, steric clashes, and protein–ligand interactions for conjugates docked into Ag85B, a key enzyme in cell wall synthesis. Shorter linkers (0–2 carbons) were found to exhibit superior binding scores, lower RMSD variability, and stronger interactions with residues such as ARG 43, including unique π–cation interactions. In contrast, longer linkers displayed increased flexibility, reduced binding specificity, and greater solvent exposure. These findings, which support our experimental observations, suggest a molecular basis for linker-dependent efficacy and provide a framework for designing next-generation porphyrin-based therapeutics for tuberculosis treatment. Full article

Cobalamin, also known as vitamin B12, is an essential cofactor involved in one-carbon metabolism, mitochondrial function, and epigenetic regulation. As humans rely entirely on dietary intake of cobalamin paired with a highly coordinated absorption and transportation system, disruptions to this metabolic process can have profound health consequences. Breast cancer, the most frequently diagnosed malignancy among women worldwide, exhibits distinct metabolic adaptations, including altered cobalamin uptake and dependency on B12-driven biochemical pathways. This review summarizes the molecular mechanisms governing cobalamin metabolism, with a focus on absorption, transport, and intracellular processes relevant to breast cancer biology. We then examine how breast cancer cells reprogram these pathways. Finally, we evaluate emerging pharmaceutical strategies that target cobalamin metabolism, including B12-based imaging probes, cobalamin-conjugated drug delivery systems, and inhibitors of B12-dependent enzymes. Although these approaches show promise, further research is needed to define subtype-specific metabolic signatures, optimize cobalamin-mediated drug targeting, and clarify how systemic B12 status influences therapeutic response. By integrating biochemical, epidemiological, and translational perspectives, this review outlines how cobalamin-centered strategies may contribute to more precise diagnostic and therapeutic options for breast cancer. Full article

In this study, a gold nanocage composite perovskite quantum dot fluorescent probe (MB-GNCs-PQDs) was designed and constructed. The GNCs-PQDs composite system was formed by the combination of gold nanocages (GNCs) and perovskite quantum dots (PQDs). Spectral analysis confirmed that its fluorescence intensity was significantly enhanced by 15.38% compared with that of pure PQDs. Furthermore, amino modification was performed on the nanomaterial. Through the specific design of molecular beacons (MB), the fluorescence emission spectrum of the probe was matched with the absorption peak of the quencher group BHQ2, and the effective closure of the fluorescence signal was achieved based on the Fluorescence Resonance Energy Transfer (FRET) effect. Subsequently, MB was immobilized on the surface of the composite system via amino covalent conjugation to complete the probe preparation. The prepared probe was applied to the detection of miRNA-4529-3P and miR-301b-3p, which are tumor markers of non-small cell lung cancer (NSCLC). The hybridization of target molecules with MB could trigger the disruption of FRET and the recovery of fluorescence signal, exhibiting excellent recognition performance. This study provides an experimental basis for the preparation of composite fluorescent probes, and the developed probe has potential application value in the field of tumor marker detection. Full article

Theranostic approaches employing radioactive materials have emerged as innovative strategies that integrate molecular imaging with targeted therapy using nanosystems, thereby advancing the paradigm of precision medicine in oncology. Each year, substantial research efforts are dedicated to developing molecular probes capable of detecting early-stage tumors, with improved efficacy and reduced toxicity to the surrounding healthy tissues. Radiopharmaceuticals based on vitamins and nanoparticles are among the most promising developments in this field, as they possess a high level of specificity and low toxicity. Vitamin B9 and vitamin B12 represent notable examples, as their targeting properties exploit the overexpression of corresponding receptors in tumor cells. In this context, future directions may include the radiolabeling of nanoparticles functionalized with these vitamins using isotopes such as [⁶⁸Ga] and [¹⁷⁷Lu], thereby enabling both diagnostic imaging and therapeutic applications. Despite the encouraging preclinical evidence, many in vitro and in vivo studies employing these strategies do not sufficiently address their translational applicability to radiotheranostics. This review highlights the most promising advances in the diagnostic and therapeutic potential of vitamin and nanoparticle-based systems. It aims to critically evaluate current findings and propose hypotheses for further study in the emerging field of radiopharmaceutical theranostics. Full article

Background: Memory B cells (B_mem) facilitate the generation of renewed and rapid antigen-specific antibody responses long after the initial antigen exposure, at a time when circulating serum antibodies may have declined. As the generation and/or recruitment of B_mem is at the core of most vaccination strategies, the assessment of antigen-specific B_mem is highly informative for forecasting and profiling the elicited B cell immune response. Methods: The two prevalent techniques used to detect antigen-specific B_mem cells at single-cell resolution are probe-based flow cytometry and B cell ImmunoSpot, while the measurement of B cell-derived antibodies in culture supernatants of stimulated B cells offers a semi-quantitative alternative. To the best of our knowledge, a direct side-by-side comparison of these assay systems has not yet been reported using the same starting PBMC material in a blinded fashion to test all three assays simultaneously. Results: These three assay systems were run in parallel to detect SARS-CoV-2 Wuhan-1 strain Spike-specific IgG⁺ B_mem in peripheral blood mononuclear cell (PBMC) samples obtained from well-defined cohorts comprising pre-COVID-19 era “naïve” individuals (negative controls), individuals shortly after recovery from a PCR-verified SARS-CoV-2 infection (positive controls), and a cohort of donor PBMCs isolated in 2024 (the experimental group). Each assay was able to discern Spike-exposed individuals from naïve , with ImmunoSpot suggesting superior sensitivity and specificity. ImmunoSpot and flow cytometry results were closely correlated. Conclusions: The study demonstrates that all three assays are suited for the detection of specific B_mem in antigen-primed individuals when such B_mem occur in the mid- to high-frequency range, and that they broadly concur. Strengths and weaknesses of the three test systems are discussed. Full article

Background/Objectives: Transdermal formulations are widely utilized in the pharmaceutical and cosmetic fields because they enable non-invasive administration and sustained local drug delivery. Conventional ex vivo skin permeation experiments using Franz diffusion cells have limitations in capturing the spatial and temporal dynamics of skin penetration. This study aimed to develop a confocal laser scanning microscopy (CLSM)-based approach to visualize and semi-quantitatively assess the penetration behavior of fluorescent dyes with differing lipophilicities. Methods: Four fluorescent dyes with different Log P values—Rhodamine B (Rho-B), Rhodamine 123 (Rho-123), Fluorescein Sodium (Flu-Na), and Nile Red (NR)—were formulated into lotion-based vehicles and applied to excised human abdominal skin. CLSM imaging was performed from 10 min to 240 min post-application. Fluorescence intensities were extracted from depth-resolved regions (R1–R4, 30-μm intervals) to examine penetration kinetics and distribution. Results: CLSM imaging demonstrated that Rho-B penetrated through stratum corneum and entered deep into the skin via the hair follicles. Rho-123 and Flu-Na exhibited intercellular and follicular penetration; however, Flu-Na showed only a slight increase in intensity over time; NR showed negligible penetration into the deeper layers. The results of our analysis indicated that moderately lipophilic substances such as Rho-B and Rho-123 diffused deeply into the skin via both transdermal and follicular routes, whereas highly hydrophobic or lipophilic substances remained in the superficial layers. Conclusions: The CLSM-based approach enabled spatially and temporally resolved, semi-quantitative evaluation of transdermal penetration in a single, non-destructive experiment. Although restricted to fluorescent probes, this approach provides a practical early-stage screening tool for comparing route-specific and time-dependent penetration behaviors of compounds with different lipophilicities. Full article

Introduction: Dengue virus (DENV) remains a global health threat, with four distinct serotypes (DENV1-4) that complicate vaccine development due to low-affinity, cross-reactive antibodies that increase the risk of antibody-dependent enhancement (ADE). Objective: To address the challenge of inducing strictly serotype-specific immune responses, this study explored the use of targeting individual lymph nodes (LNs) for the creation of simultaneous but independent immune responses as a targeted approach to reduce cross-reactivity and improve vaccine specificity. Methods: In the initial experiments, targeting individual LN successfully induced specific germinal centers (GCs) for different antigens in distinct LNs, highlighting its potential to enhance immune specificity. This approach was further tested using two virus-like particle (VLP)-based vaccines based on AP205 for DENV1 and DENV4, selected due to their genetic divergence and to probe the potential to minimize cross-reactive immune responses. In this setup, AP205-DV1 and AP205-DV4 were administered in targeted separate LNs, and the specificity of the immune response was compared to subcutaneous administration of a mixture of both vaccines. Results: Our data show that targeting distinct LNs elicited antibodies with significantly higher avidity, which is a critical factor in determining the neutralizing capacity of the immune response. Avidity measurements confirmed that this segregation approach results in a more refined selection of high-affinity B cells. Neutralization experiments demonstrated that targeting distinct LNs with individual vaccines induced a more potent and serotype-specific neutralizing response, compared to the injection of a vaccine mixture. Conclusions: These findings suggest that targeting individual LNs could be a promising method for enhancing both the specificity and potency of immune responses, particularly for flaviviruses. Targeting distinct LNs by direct administration of individual vaccines into distinct watersheds rather than individual lymph nodes will offer the opportunity to facilitate the approach in humans. Full article

Background and Objectives: This study aimed to investigate the anticancer effects and potential synergistic interactions of quercetin (Q) and doxorubicin (Dox) on the MG-63 osteosarcoma (OS) cell line. Specifically, the effects of these agents on cell viability, apoptosis, reactive oxygen species (ROS) generation, antioxidant defense, and the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt1) signaling pathway were evaluated. Material and Methods: MG-63 cells were cultured and treated with varying concentrations of Q and Dox, both individually and in combination (fixed 5:1 molar ratio), for 48 h. Cell viability was assessed using an MTT assay, and IC₅₀ values were calculated. Synergistic effects were analyzed using the Chou–Talalay combination index (CI). Apoptosis was evaluated via Annexin V-FITC/PI staining and caspase-3/7 activity. ROS levels were quantified using DCFH-DA probe, and antioxidant enzymes (SOD, GPx) were measured spectrophotometrically. Gene expression (Runx2, PI3K, Akt1, caspase-3) was analyzed by reverse transcription quantitative polymerase chain reaction (RT-qPCR). Results: Q and Dox reduced cell viability in a dose-dependent manner, with IC₅₀ values of 70.3 µM and 1.14 µM, respectively. The combination treatment exhibited synergistic cytotoxicity (CI < 1), especially in the Q50 + Dox5 group (CI = 0.23). Apoptosis was significantly enhanced in the combination group, evidenced by increased Annexin V positivity and caspase-3 activation. ROS levels were markedly elevated, while antioxidant enzyme activities declined. RT-qPCR revealed upregulation of caspase-3 and downregulation of Runx2, PI3K, and Akt1 mRNA levels. Conclusions: The combination of Q and Dox exerts synergistic anticancer effects in MG-63 OS cells by inducing apoptosis, elevating oxidative stress, suppressing antioxidant defense, and inhibiting the PI3K/Akt1 signaling pathway and Runx2 expression. These findings support the potential utility of Q as an adjuvant to enhance Dox efficacy in OS treatment. Full article

Background/Objective: Noninvasive PET imaging-based assessment of PD-L1 expression is of high clinical value for better patient selection and treatment response rates to PD-L1 immunotherapies. Due to their shorter biological half-life and faster clearance from the blood pool, radiolabeled antibody fragments are an attractive alternative for imaging than their full-length IgG counterpart. This work investigated the radiosynthesis and in vitro cell uptake of anti-PD-L1-B11-nanobody radiolabeled with ⁴⁴Sc (t_1/2 = 4.04 h) as an alternative to anti-PD-L1-B11-IgG, better suited for longer half-life radioisotopes such as ⁸⁹Zr (t_1/2 = 78.41 h). Methods: The proteins were conjugated with p-SCN-Bn-DTPA and radiolabeled at room temperature with ⁴⁴Sc, achieving a radiochemical yield of a RCY of 94.8 ± 3.1% (n = 3) for [⁴⁴Sc]Sc-B11-IgG and 73.6 ± 12.1% (n = 3) for [⁴⁴Sc]Sc-B11-nanobody, before purification. Results: Significantly higher uptake in the PD-L1₊ cells than PD-L1_KO cells was observed for both probes. However, high non-specific uptake, particularly of the radiolabeled B11-nanobody, was also observed which may negatively impact its potential as a molecular imaging probe. Conclusions: Due to the high non-specific uptake in vitro, the ⁴⁴Sc radiolabeled nanobody was not progressed to further in vivo evaluation. These results should, however, not discourage future evaluations of other nanobody based probes radiolabeled with ⁴⁴Sc, due to their well-matched biological and physical half-life. Full article

Dengue is a neglected disease mainly affecting tropical and subtropical countries. The diagnosis of dengue fever is still a problem since most of it is made from whole or recombinant DENV proteins, which present cross-reactions with other members of the Flavivirus family. Therefore, there is still a huge demand for new diagnostic methods that provide rapid, low-cost, easy-to-use confirmation. Thus, in this study, we developed an affordable electrochemical biosensor for rapidly detecting immunoglobulin G (IgG) serological antibodies in the sera of DENV-infected patients. An identified linear B-cell epitope (DENV/18) specific for DENV 1–4 serotypes recognized by IgG in patient sera was selected as a target molecule after a microarray of peptides using the SPOT-synthesis methodology. After chemical synthesis, the DENV/18-peptide was immobilized on the surface of the working electrode of a commercially available screen-printed gold electrode (SPGE). The capture of DENV-specific IgG allowed for the formation of an immunocomplex that was measured by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) using a potassium ferrocyanide/ferricyanide ([Fe(CN)₆]^3−/4−) electrochemical probe. An evaluation of the biosensor’s performance showed a detection limit of 100 µg mL⁻¹ for the synthetic peptides (DENV/18) and 1.21 ng mL⁻¹ in CV and 0.43 ng mL⁻¹ in DPV for human serum, with a sensitivity of 7.21 µA in CV and 8.79 µA in DPV. The differentiation of infected and uninfected individuals was possible even at a high dilution factor that reduced the required sample volumes to a few microliters. The final device proved suitable for diagnosing DENV by analyzing real serum samples, and the results showed good agreement with molecular biology diagnostics. The flexibility to conjugate other antigenic peptides to SPEs suggests that this technology could be rapidly adapted to diagnose other pathogens. Full article