Search Results (365)

Background: Multidrug efflux proteins, frequently overexpressed in cancer cells, reduce intracellular drug accumulation and limit chemotherapeutic efficacy. Short drug-binding peptides containing the WXXW motif have been shown to non-covalently bind multidrug resistance (MDR)-associated drugs, potentially masking structural features recognized by efflux transporters. We hypothesized that incorporating this motif into a membrane-active peptide would generate a hybrid analogue capable of reversible drug binding and enhanced cellular uptake. Methods: A melittin-derived peptide (M3) was rationally designed by introducing the WXXW motif into the flexible region adjacent to the conserved proline kink to generate a dual-functional peptide with membrane activity and reversible drug binding. Membrane activity was evaluated using liposome leakage assays, and drug-binding interactions with doxorubicin were characterized using fluorescence quenching and microscale thermophoresis (MST). Molecular dynamics simulations were performed to elucidate binding mechanisms, and functional effects were assessed using calcein AM efflux assays, confocal imaging, and cytotoxicity studies across cancer cell lines. Results: M3 retained membrane activity and exhibited moderate, reversible binding to doxorubicin, with simulations showing binding initiation at the WXXW motif and extension to tryptophan residues W12, W15, and W19, forming a multivalent aromatic interface that suggested shielding of key drug functionalities. Functionally, M3 enhanced intracellular calcein retention and increased doxorubicin accumulation, and combination treatment produced synergistic cytotoxicity in the multidrug-resistant H69AR cell line with reduced toxicity toward normal epithelial cells. Conclusions: M3 acts as a membrane-active, reversible drug-binding peptide that enhances intracellular drug accumulation, supporting its potential as a modular strategy to overcome efflux-mediated MDR. Full article

Sideritis species (Lamiaceae), the aromatic mountain teas of the Mediterranean and Balkans, accumulate a phytochemically rich array of bioactive compounds—phenylethanoid glycosides (notably verbascoside), flavonoid aglycones and glycosides, phenolic acids, and terpenoids—whose pharmacological relevance is increasingly defined at the molecular level. This review synthesizes current evidence on the molecular mechanisms through which these constituents act in human health and disease, integrating in vitro, in vivo, in silico, and clinical data. Anti-inflammatory activity is attributed to modulation of the NF-κB and NLRP3 inflammasome pathways; direct verbascoside binding to both targets has been demonstrated in vitro by microscale thermophoresis (nanomolar-to-micromolar Kd), with suppression of TNF-α and IL-1β observed in cell-based and animal models. Neuroprotective effects are proposed to operate through amyloid-β clearance via ADAM10 upregulation and enhanced microglial phagocytosis in transgenic mouse models, together with in vitro triple monoamine (serotonin, noradrenaline, dopamine) reuptake inhibition, and are supported at the functional level by small randomized clinical trials reporting cognitive and anxiolytic benefits. Antioxidant and cytoprotective actions reflect radical scavenging, metal chelation, and restoration of SOD/CAT/GSH with attenuation of lipid peroxidation, underpinning documented hepatoprotective and gastroprotective outcomes. Preliminary cardiometabolic findings from small clinical trials include cholesterol modulation and sex-dependent effects on insulin sensitivity that remain to be confirmed in larger, adequately powered cohorts. We further evaluate structure–activity relationships, species- and tissue-level chemical variability, and green extraction strategies relevant to standardized bioactivity-preserving preparations. Critical gaps—in vivo validation of antiproliferative effects documented only in cell-based and in silico studies so far, systematic toxicological assessment, and bioavailability characterization—are identified to guide translation. Collectively, Sideritis-derived phytochemicals, exemplified by S. scardica, represent a mechanistically coherent group of plant bioactives with defined molecular targets in inflammatory, neurodegenerative, and metabolic disorders. Full article

Conventional gelatin-based hydrogels lack responsiveness to the tumor microenvironment and exhibit low drug-loading efficiency for hydrophobic drugs, which limits their application in targeted cancer therapy. In this study, a reduction-responsive gelatin hydrogel was developed by grafting hydrophobic tert-butoxycarbonyl (Boc) groups onto gelatin chains, followed by EDC/NHS-mediated chemical cross-linking with L-cysteine dimethyl ester dihydrochloride, which contains disulfide bonds. The success of Boc grafting was confirmed by ¹H NMR, and free amine quantitative analysis. Rheological characterization confirmed the formation of a stable elastic network with controllable gelation times (5–12 min), demonstrating excellent injectability. Reduction-triggered degradation was observed in the presence of DTT or GSH, with the cleavage of disulfide bonds further evidenced by the detection of free sulfhydryl (-SH) groups via X-ray Photoelectron Spectroscopy. Microscale thermophoresis (MST) demonstrated measurable binding between Boc-modified gelatin and hydrophobic drugs, with dissociation constants (K_d) of 0.46 ± 0.37 μM for curcumin and 0.14 ± 0.14 μM for camptothecin. Drug loading assays show dramatically enhanced encapsulation efficiency for hydrophobic drugs (62.7% for curcumin, 66.6% for camptothecin) compared to unmodified hydrogels (7.2% and 16.8%, respectively). In vitro release kinetics follow the Korsmeyer–Peppas model, indicating a non-Fickian diffusion–erosion mechanism, and can be precisely tuned by gelatin concentration and reducing agent levels. Complete drug release occurs within approximately 325 min in 15 mM GSH. MTT and hemolysis assays confirm high biocompatibility. Collectively, this reduction-responsive system offers a promising platform for controlled, site-specific delivery of hydrophobic anticancer agents. Full article

2,3-dimethyl-6-(1-hydroxy)-pyrazine showed significant repellent activity to diamondback moth (Plutella xylostella), the PxylPBP2 was considered as the potential molecular target, though this has not been validated. In this study, the repellent rate was significantly decreased by about 20% when the PxylPBP2 was silenced using RNAi. There was obvious interaction between 2,3-dimethyl-6-(1-hydroxy)-pyrazine and PxylPBP2, with a Kd (Dissociation constant) value of 7.78 μmol/L via microscale thermophoresis, while the value was changed to 4.45 μmol/L when the PxylOR31 (Pxyl, Plutella xylostella; OR31, Odorant receptor 31) was introduced to this compound and ligand system. Moreover, the RMSD (Root mean square deviation) value of pyrazine + PxylPBP2 + PxylOR31 treatment ranged between 0.030 and 0.125 nm; the average number of hydrogen bonds and Van der Waals interaction value can be used to summarize that there was a stronger interaction between pyrazine and PxylPBP2. Furthermore, the ILE122 (L-Isoleucine at 122 site) was an important target site during the binding process between PxylBPB2 and ligands, which was validated by performing a fluorescence competitive binding experiment. Finally, the PxylPBP2 showed a strong ability to bind to α-pinene and β-ionone with the Ki values of 10.54 μmol/L and 11.74 μmol/L, respectively. These data provide a creative strategy for developing novel insecticides, which is also important for achieving the green control of P. xylostella and delaying the development of resistance. Full article

Accurate chromosome segregation during meiosis requires protection of centromeric cohesion mediated by shugoshin (SGO) proteins and Protein Phosphatase 2A (PP2A). In Arabidopsis thaliana, genetic and cytological studies have demonstrated that PP2A B′ regulatory subunits are essential for maintaining centromeric cohesion; however, direct biochemical evidence for their interaction with SGO1 in plants is lacking. Here, we used microscale thermophoresis (MST) to investigate and quantify the binding between fluorescently labeled GST-SGO1 and the PP2A B′α and B′β subunits. SGO1 exhibited concentration-dependent binding to both subunits, with dissociation constants (Kd) of 5.49 ± 0.88 µM for B′α and 1.89 ± 0.38 µM for B′β, indicating an approximately threefold higher affinity for B′β. These results provide direct quantitative biochemical evidence for a specific interaction between Arabidopsis SGO1 and PP2A B′ subunits. Full article

Irradiation (IR) can cause intestinal epithelial cell death, damage to crypt stem cells, and mucosal barrier dysfunction, which are the features of radiation-induced intestinal injury (RIII). Our study first discovered a natural small-molecule alkaloid Orychophragine D (OV16) with an obvious radiation protection effect. This study aims to investigate the radiation protection effect of OV16 on RIII and its potential molecular mechanism. The results showed that in vitro OV16 exhibited a significant protective effect on an irradiated human small intestinal epithelial cell-6 (HIEC-6) model. Then, transglutaminase 2 (TGM2), which is the key protein for OV16 to exert its anti-RIII protective effect, was identified as a crucial cellular target of OV16 using drug affinity responsive target stability (DARTS), molecular docking, molecular dynamics simulation, cell thermal shift assay (CETSA), and microscale thermophoresis (MST). Moreover, OV16 can upregulate the expression level of TGM2 in the nucleus of HIEC-6. TGM2 can reduce radiation-induced damage by enhancing the proliferation ability and migration ability of HIEC-6 and reducing the generation of γ-H2AX. Collectively, our study first identified TGM2 as a previously unreported therapeutic target for RIII, and provided a future drug design direction for TGM2 allosteric activators using OV16 as a novel molecular template. Full article

In prokaryotes, translation initiation orchestrates protein synthesis through a network of dynamic interactions among the ribosome, mRNA, initiator tRNA^fMet, and initiation factors (IFs). Traditional approaches that rely on radioactive labeling or surface immobilization are hindered by inherent safety risks and methodological constraints. We present a fluorescence-based analytical platform that integrates microscale thermophoresis (MST) as a unified, multiparametric toolkit for comprehensive interrogation of bacterial translation initiation at the molecular level. By systematically applying MST to a panel of fluorescently labeled components—initiator tRNA^fMet, mRNAs, and initiation factors—we quantify assembly pathways and equilibria as initiation progresses from simple bimolecular interactions to higher-order, multicomponent complexes. To broaden the fluorescence toolbox for ribosomal studies, we developed a robust BODIPY-labeling protocol for 70S ribosomes and confirmed preservation of structural integrity and function by nano differential scanning fluorimetry, stopped-flow kinetic assays, and peptide-synthesis activity tests. Our microscale fluorescent system facilitates probing initiation at a variety of steps, since the role of magnesium ions and initiation factors upon 30S initiation complex formation. The same platform can be applied to investigate the effects of different compounds on translation initiation, as demonstrated for a number of antibiotics, aptamers, and antimicrobial peptides. Using this approach, we determined the antibiotic streptomycin dissociation constant for both 30S and 70S ribosomes, which proved identical at 0.3 ± 0.1 μM, and demonstrated the effect of the antimicrobial peptide rumicidin-1 on translation initiation. Offering a cost-effective and high-sensitivity alternative to conventional methods, this approach advances mechanistic understanding of prokaryotic translation and provides a versatile framework for the discovery of novel protein synthesis inhibitors. Full article

Significance: This study addresses critical industrial and biomedical applications including glass blowing (thermal management of shrinking sheets), polymer sheet extrusion (controlled cooling), magnetic drug delivery (nanoparticle targeting), and nuclear reactor cooling (enhanced heat transfer). Aim: We present a novel nonlinear analysis of magnetohydrodynamic (MHD) boundary layer flow of a Jeffery Al₂O₃ nanofluid over a shrinking permeable plate with convective boundary conditions, uniquely integrating mixed convection, Ohmic dissipation, heat generation, Brownian motion, and thermophoresis within a non-Newtonian nanofluid framework. Methodology: The governing partial differential equations are transformed using similarity transformations and solved via the Adomian decomposition method (ADM). Comprehensive validation against RK4, RK45, and bvp4c demonstrates excellent agreement with maximum relative errors below $5\times {10}^{-4}$. Key Contribution: (i) Normal velocity decreases by 15–25% as the Biot number increases from $Bi=0.4$ to $0.6$; (ii) tangential velocity decreases by 20–30% as the magnetic parameter increases from $M=5$ to 15; (iii) temperature increases by 30–40% as the Eckert number increases from $Ec=0.5$ to $2.5$; (iv) ADM converges within 12–15 terms with $L_2$ errors $<{10}^{-5}$; (v) skin friction coefficient increases from $C_f=3.02713$ to $3.90082$ as $Q_0$ increases from 1 to 4; (vi) Nusselt number values: $Nu/\sqrt{Re}=0.4621$ at $Pr=0.7$, $0.8954$ at $Pr=2$, $3.2890$ at $Pr=20$. These quantitative findings provide design guidelines for engineers in thermal management and biomedical applications. Full article

Background/Objectives: The most abundant flavonoid, quercetin, which is mostly found as glycosides, is widely distributed in plants. Quercetin is rapidly metabolized, having a short half-life in the blood circulation, and forms its conjugates by undergoing ring cleavage of the benzopyranone ring system. Despite its fast clearance in the body, quercetin was demonstrated to have clinically anti-inflammatory, cardioprotective, antidiabetic, and anti-obesity activities. This study aimed to determine whether quercetin itself or its metabolites are responsible for these activities. Methods: We performed molecular docking of 27 metabolites, including quercetin itself, against ten inflammation-related proteins in silico. We then conducted microscale thermophoresis (MST) of selected metabolites towards the NLRP3 inflammasome. Results: Overall, Phase II metabolites yielded better binding energies compared to the metabolites formed by degradation. MST results revealed that isorhamnetin, the 4-O-methylated metabolite of quercetin, gave the best results, with a binding affinity (K_D value) of 16.12 ± 5.16 µM, even better than quercetin itself, which has a binding affinity of 44.84 ± 4.21 µM. Glucuronide metabolites of quercetin (isorhamnetin 3-O-glucuronide, quercetin 7-O-glucuronide, and quercetin 3-O-glucuronide) were found to bind to the inflammasome protein with low binding affinities, whereas small degradation products (hippuric acid and 3,4-dihydroxytoluene) did not bind at all. Conclusions: These results suggest that Phase II metabolites, specifically isorhamnetin, may contribute more significantly to the biological activity of quercetin than the parent compound, however, degradation products appear inactive. Full article

This study presents a numerical investigation of the laminar forced convection of polyethylene glycol-based nanocolloids within a horizontal pipe. To bridge the gap between theoretical predictions and practical performance, simulations were conducted over a Reynolds number range of 500 to 2000, utilizing a model validated against laboratory-scale experimental data and well-defined boundary conditions. Our analysis focuses on the thermal behavior of polyethylene glycol 200 enriched with metal oxide nanoparticles and multi-walled carbon nanotubes, which were selected for their capacity to enhance thermal conductivity while maintaining manageable viscosity. The results demonstrate that PEG 200-based nanocolloids significantly improve heat transfer performance in the laminar regime. This enhancement is attributed to the superior intrinsic thermal properties of the nanoparticles and the complex synergistic interactions—such as Brownian motion and thermophoresis—between the particles and the PEG base fluid. A critical evaluation of the standard approach of incorporating thermophysical properties into the numerical approach led to significant discrepancies in flow predictions. Additionally, our study establishes that assuming constant thermophysical properties during the heating process introduces simulation errors exceeding 10%. These findings underscore the necessity of incorporating temperature-dependent, experimentally validated data into numerical models to ensure predictive accuracy. Ultimately, this work advocates for a nuanced approach to nanocolloid design that prioritizes the specific chemical and rheological compatibility between nanoparticle types and the base fluid. Full article

This study introduces an efficient and accurate two-stage explicit computational scheme for solving partial differential equations (PDEs) containing first-order time derivatives. The suggested method is a modification of the classical Runge–Kutta scheme that introduces a new first-stage formulation. This minimizes numerical error with moderate step sizes while preserving the stability region of the classical method. Spatial discretization is performed using a sixth-order compact finite-difference scheme to obtain high-resolution solutions. The analysis of stability and convergence is strictly determined for both scalar and system forms of convection–diffusion-type equations. To illustrate the suitability of the method, a dimensionless mathematical model of the unsteady, incompressible, laminar flow of a Prandtl-type non-Newtonian nanofluid over a Riga plate is considered, accounting for viscous dissipation, thermophoresis, Brownian motion, and a magnetic field. Here, the Prandtl ternary nanofluid is defined as a non-Newtonian nanofluid that follows the Prandtl rheological model, and it exhibits three critical transport phenomena: heat conduction, viscous dissipation, and nanoparticle diffusion. Representative values of the Prandtl number $P_r=3$ and Reynolds number $R_e=5$ are used to perform the simulation, and other parameters, including but not limited to the Hartmann number $H_a$, Williamson number $W_e$, thermophoresis $N_t$ and Brownian motion $N_b$, are varied to evaluate the flow behavior. Moreover, an artificial neural network (ANN)-developed surrogate model is used to calculate the skin friction coefficient and the local Sherwood number, using five input parameters: the Reynolds number, Prandtl number, Schmidt number, Brownian motion parameter, and thermophoresis parameter. The governing partial differential equations yield high-fidelity numerical data used to train the surrogate model. The data is split into 80% for training, 10% for validation, and 10% for testing. The ANN is tested using regression analysis and error histograms, which demonstrate high accuracy and generalization capacity. Numerical simulation combined with AI-based prediction is a cost-efficient method for real-time estimation of complex non-Newtonian nanofluid systems. Full article

This is a review article that covers the history of the development of the equation of motion for solid particles in fluids, starting with the early work, before the Navier–Stokes equations were developed. Particular emphasis is placed on the development of the transient equation of motion, which features the history (or memory) term and the added mass (virtual mass) term. The salient features of the equation and the methods of their derivation are pointed out. Creeping, non-inertia flows as well as advective flows are surveyed, with particular emphasis on their effects on the functional form of the history term. Modifications to the hydrodynamic force due to possible interface slip are also examined. The review also deals with the inclusion of the weaker lateral (lift) forces and the inclusion of the effects of Brownian movement, which gives rise to thermophoresis—an important source of nanoparticle movement and surface deposition. The drag on irregularly shaped particles—another important feature of nanoparticles—is also examined. The review concludes with a short section on significant unknown issues and work that may be carried out in the near future for the theoretical and computational development of the subject. Full article

An analysis is presented for the steady thermophoresis and photophoresis of a homogeneous dispersion of identical aerosol spheres of typical physical properties and surface characteristics. The analysis assumes a moderately small Knudsen number (less than about 0.1), such that the gas motion lies within the slip-flow regime, including thermal creep, temperature jump, thermal stress slip, and frictional slip at the particle surfaces. Under conditions of low Peclet and Reynolds numbers, the coupled momentum and energy equations are analytically solved using a unit cell approach that explicitly incorporates interparticle interactions. Closed-form expressions are derived for the mean particle migration velocities in both thermophoresis driven by a uniform temperature gradient and photophoresis induced by an incident radiation field. The results reveal that the normalized particle velocities, referenced to those of an isolated particle, generally decrease with increasing particle volume fraction, though exceptions occur for thermophoresis. While thermal stress slip and thermal creep exert no influence on the normalized thermophoretic velocity, they markedly affect the normalized photophoretic velocity, which rises with the thermal stress slip to the thermal creep coefficient ratio. For both phenomena, the normalized migration velocities increase monotonically with the particle-to-fluid thermal conductivity ratio. Full article

The p53 tumor suppressor, a key transcription factor, acts as a cellular stress sensor that regulates hundreds of genes involved in responses to DNA damage, oxidative stress, and ischemia. Through these actions, p53 can arrest cell cycle, initiate DNA repair, or trigger cell death. In addition to its nuclear functions, p53 can translocate to mitochondria to promote apoptosis. Studies using isolated mitochondria have suggested that p53 drives the voltage-dependent anion channel (VDAC1) into high molecular mass complexes to mediate apoptosis. VDAC1 is a central regulator of cellular energy production and metabolism and also an essential player in apoptosis, induced by various apoptotic stimuli and stress conditions. We previously demonstrated that VDAC1 oligomerization, induced by various apoptosis stimuli and stress conditions, forms a large pore that enables cytochrome c release from mitochondria, thereby promoting apoptotic cell death. In this study, we show that p53 interacts with VDAC1, modulates its expression levels, and promotes VDAC1 oligomerization-dependent apoptosis. Using purified proteins, we found that p53 directly binds VDAC1, as revealed by microscale thermophoresis and by experiments using bilayer-reconstituted VDAC1, in which p53 reduced VDAC1 channel conductance. Furthermore, overexpression of p53 in p53-null cells or in cells expressing wild-type p53 increased VDAC1 expression and induced VDAC1 oligomerization even in the absence of apoptotic stimuli. Together, these findings identify VDAC1 as a direct p53 target whose expression, oligomerization, and pro-apoptotic activity are regulated by p53. They also reinforce the central role of VDAC1 oligomerization in apoptosis. Full article

Background: Atherosclerosis (AS) serves as the primary pathological basis for cardiovascular disease-related deaths worldwide, posing a severe threat to public health security. Heat shock protein 90 (HSP90) plays a crucial regulatory role in the pathological progression of AS, emerging as a potential target for anti-atherosclerosis drug development in recent years. Calenduloside E (CE) is a pentacyclic triterpenoid saponin isolated from Aralia elata (Miq.) Seem. Previous studies have confirmed its anti-atherosclerotic activity, but its weak efficacy and narrow therapeutic index limit its clinical application. In this study, the CE scaffold was hybridized with a ticagrelor-derived fragment to enhance anti-atherosclerotic activity. In this study, the CE scaffold was hybridized with a ticagrelor fragment to achieve improved activity. Methods: Based on the principle of molecular hybridization, CE was linked to the active fragment of ticagrelor via a PEG chain. Ten CE derivatives were synthesized by modifying the sugar substituents. In vitro experiments were conducted to detect cytotoxicity and protective activity against ox-LDL-induced HUVECs injury. Molecular docking and Surface Plasmon Resonance (SPR) assays were used to evaluate the interaction between CE derivatives and the known target HSP90β. Combined with Microscale Thermophoresis (MST), SwissTargetPrediction, and molecular docking, other potential targets of CE derivatives were identified. Results: In the ox-LDL-induced HUVECs injury model, all compounds except C2 and C9 exhibited protective activity. Among these compounds, compound C5 exhibited the optimal protective effect, with an EC₅₀ value of 1.44 μM. Molecular docking results revealed that both C5 and CE could bind to HSP90β by forming hydrogen bonds with the key amino acid Asp93. Additionally, SPR results indicated that C5 and CE had similar binding affinities to HSP90β, with dissociation constants (K_D) of 1.73 μM and 1.72 μM, respectively. MST demonstrated that C5 binds to HSP90β with an affinity 111 times higher than that of ticagrelor. SwissTargetPrediction and molecular docking identified P2Y12 as another potential target of derivative C5. Conclusions: Compound C5 exerts protective effect against ox-LDL-induced HUVECs injury by targeting HSP90β. Its effective concentration is significantly improved compared with that of the parent CE, which provides a possibility for reducing clinical dosage and toxic side effects in subsequent studies. Furthermore, C5 may exert its effects by targeting another potential target, P2Y12, offering references for the rational design of novel anti-atherosclerotic drugs. Full article