New Insights into Dyskerin-CypA Interaction: Implications for X-Linked Dyskeratosis Congenita and Beyond

The highly conserved family of cyclophilins comprises multifunctional chaperones that interact with proteins and RNAs, facilitating the dynamic assembly of multimolecular complexes involved in various cellular processes. Cyclophilin A (CypA), the predominant member of this family, exhibits peptidyl-prolyl cis-trans isomerase activity. This enzymatic function aids with the folding and activation of protein structures and often serves as a molecular regulatory switch for large multimolecular complexes, ensuring appropriate inter- and intra-molecular interactions. Here, we investigated the involvement of CypA in the nucleus, where it plays a crucial role in supporting the assembly and trafficking of heterogeneous ribonucleoproteins (RNPs). We reveal that CypA is enriched in the nucleolus, where it colocalizes with the pseudouridine synthase dyskerin, the catalytic component of the multifunctional H/ACA RNPs involved in the modification of cellular RNAs and telomere stability. We show that dyskerin, whose mutations cause the X-linked dyskeratosis (X-DC) and the Hoyeraal-Hreidarsson congenital ribosomopathies, can directly interact with CypA. These findings, together with the remark that substitution of four dyskerin prolines are known to cause X-DC pathogenic mutations, lead us to indicate this protein as a CypA client. The data presented here suggest that this chaperone can modulate dyskerin activity influencing all its partecipated RNPs.

Allicin-Loaded Intelligent Hydrogel Coating Improving Vascular Implant Performance

Coronary atherosclerosis is closely related to inflammation and oxidative stress. Owing to poor biocompatibility, lack of personalized treatment, and late toxic side effects, traditional drug-eluting stent intervention, releasing antiproliferative drugs, can delay endothelial repair and cause late thrombosis. The inflammation caused by atherosclerosis results in an acidic microenvironment and oxidative stress, which can be considered as triggers for precise and intelligent treatment. Here, we used catechol hyaluronic acid (C-HA) and cystamine (Cys) to prepare C-HA-Cys hydrogel coatings by amide reaction. The H2S-releasing donor allicin was loaded in the hydrogel to form an intelligent biomimetic coating. The disulfide bond of Cys made the cross-linked network redox-responsive to the inflammation and oxidative stress in the microenvironment by releasing the drug and H2S intelligently to combat the side effects of stent implantation. This study evaluated the hemocompatibility, anti-inflammatory capacity, vascular wall cytocompatibility, and in vivo histocompatibility of this intelligent hydrogel coating. Furthermore, the effect of H2S released from the coating on atherosclerosis-related signaling pathways such as CD31 and cystathionine γ-lyase (CSE), CD36, and ACAT-1 was investigated. Our results indicate that the C-HA-Cys-Allicin hydrogel coating could be manufactured on the surface of vascular interventional devices to achieve a precise response to the microenvironment of the lesion to release drug, which can attain the purpose of prevention of in-stent restenosis and ensure the effectiveness and safety of the application of interventional devices.

Apoptosis-Sensing Xenograft Zebrafish Tumor Model for Anticancer Evaluation of Redox-Responsive Cross-Linked Pluronic Micelles

A suitable animal model for preclinical screening and evaluation in vivo could vastly increase the efficiency and success rate of nanomedicine development. Compared with rodents, the transparency of the zebrafish model offers unique advantages of real-time and high-resolution imaging of the whole body and cellular levels in vivo. In this research, we established an apoptosis-sensing xenograft zebrafish tumor model to evaluate the anti-cancer effects of redox-responsive cross-linked Pluronic polymeric micelles (CPPMs) visually and accurately. First, doxorubicin (Dox)-loaded CPPMs were fabricated and characterized with glutathione (GSH)-responsive drug release. Then, the B16F10 xenograft zebrafish tumor model was established to mimic the tumor microenvironment with angiogenesis and high GSH generation for redox-responsive tumor-targeting evaluation in vivo. The high GSH generation was first verified in the xenograft zebrafish tumor model. Compared with ordinary Pluronic polymeric micelles, Dox CPPMs had a much higher accumulation in zebrafish tumor sites. Finally, the apoptosis-sensing B16F10-C3 xenograft zebrafish tumor model was established for visual, rapid, effective, and noninvasive assessment of anti-cancer effects at the cellular level in vivo. The Dox CPPMs significantly inhibited the proliferation of cancer cells and induced apoptosis in the B16F10-C3 xenograft zebrafish tumor model. Therefore, the redox-responsive cross-linked Pluronic micelles showed effective anti-cancer therapy in the xenograft zebrafish tumor model. This xenograft zebrafish tumor model is available for rapid screening and assessment of anti-cancer effects in preclinical studies.

Precision-cut liver slices as a model for assess hepatic cellular response of chitosan-glutathione nanoparticles on cultures treated with zilpaterol and clenbuterol

Zilpaterol and clenbuterol are two β-adrenergic agonist drugs used in animal production. Both drugs have anabolic effects with advantages on carcass yield. Meanwhile, zilpaterol is approved for animal feed in authorized countries. Clenbuterol is a banned substance due to the risk of toxicity; however, it is still being used in unknown dose levels in many farm species. Therefore, the use and abuse of these substances should be closely monitored, considering the clenbuterol ability and the not proved yet of zilpaterol to produce reactive oxygen and nitrogen species. Regarding glutathione which is the main intracellular antioxidant plays detoxification functions on liver metabolism; in this work, it is our interest to know the capacity of chitosan-glutathione nanoparticles (CS/GSH-NP) as a complementary source of exogenous GSH to modify the oxide-reduction status on bovine precision-cut liver slice cultures (PCLS) exposed to clenbuterol and zilpaterol. A single drug assay was performed in first instance by adding clenbuterol, zilpaterol, chitosan nanoparticles (CS-NP), and CS/GSH-NP. Then combinate drug assay was carried out by testing clenbuterol and zilpaterol combined with CS-NP or CS/GSH-NP. The results showed that both β-adrenergic agonists modify in a dose-dependent manner in oxide-reduction response through ROS generation. The activity or content of glutathione peroxidase activity, intracellular GSH, gamma glutamyl-transpeptidase, aspartate aminotrasnferase and alanine aminotrasnferase were modified. The exogenous GSH delivered by nanoparticles could be used to modulate these markers.

Engineering Paclitaxel Prodrug Nanoparticles via Redox-Activatable Linkage and Effective Carriers for Enhanced Chemotherapy

The current clinical performance of chemotherapy is far from satisfactory, greatly limited by insufficient delivery efficacy and serious systemic side effects. Dimeric prodrug systems are emerging as valuable strategies for boosting the antitumor outcome. Here, dimeric paclitaxel prodrugs were synthesized with different bridged linkers, and the formed prodrug nanoparticles possessed excellent colloidal stability and ultrahigh drug content. The diselenide bond containing paclitaxel prodrugs could respond to a redox-heterogeneous intracellular microenvironment for on-demand drug release and subsequently show a selective cytotoxicity toward tumor cells against normal cells. Furthermore, the optimal carrier materials were screened out according to their contribution on stability, endocytosis, cytotoxicity, biodistribution, and antitumor efficacy. Compared with DSPE-PEG, human serum albumin, and Fe-tannic acid-based complex, F127 anchored dimeric paclitaxel nanoformulations exhibited preferential tumor accumulation and potent anticancer effect. Our present work provides deep insight into the development of advanced nanoformulations with comprehensive advantages for enhancing cancer therapy.

Redox-Sensitive Cysteines Confer Proximal Control of the Molecular Crowding Barrier in the Nuclear Pore

The nuclear pore complex forms a highly crowded selective barrier with intrinsically disordered regions at the nuclear membrane to coordinate nucleocytoplasmic molecular communications. Although oxidative stress is known to alter the barrier function, the molecular mechanism underlying this adaptive control of the nuclear pore complex remains unknown. Here we uncover a systematic control of the crowding barrier within the nuclear pore in response to various redox environments. Direct measurements of the crowding states using a crowding-sensitive FRET (Förster resonance energy transfer) probe reveal specific roles of the nuclear pore subunits that adjust the degree of crowding in response to different redox conditions, by adaptively forming or disrupting redox-sensitive disulfide bonds. Relationships between crowding control and the barrier function of the nuclear pore are investigated by single-molecular fluorescence measurements of nuclear transport. Based on these findings, we propose a proximal control model of molecular crowding in vivo that is dynamically regulated at the molecular level.

Lutein inhibits breast cancer cell growth by suppressing antioxidant and cell survival signals and induces apoptosis

Reduced risk of breast cancer upon intake of lutein-rich food supplements creates an interest to investigate the molecular mechanism underlying the growth inhibitory potential of lutein in MCF-7 and MDA-MB-231 cells. Lutein purified from Spinacia oleracea was identified by high-performance liquid chromatography and liquid chromatography-mass spectrometry. The cell viability was measured by water-soluble tetrazolium-1 assay. The intracellular reactive oxygen species level was examined by 2',7'-dichlorofluorescein assay. The protein expression of the markers of antioxidant defense, cell survival, and apoptosis was analyzed by western blot analysis. The induction of apoptosis by lutein was measured by 4',6-diamidino-2-phenylindole staining and caspase-3 activity assay. The purified lutein inhibited the viability of MCF-7 and MDA-MB-231 cells. The growth inhibitory effect of lutein was associated with suppressed protein expression of superoxide dismutase-2 and heme oxygenase-1, and its transcription factor nuclear factor erythroid 2-related factor-2. Lutein treatment subsequently blocked the expression of intracellular cell survival proteins, phosphorylated protein kinase B, phosphorylated extracellular-regulated kinase 1/2, and nuclear factor-kB. Suppression of antioxidant defense and cell survival markers by lutein was further linked to apoptosis induction with elevated caspase-3 activity and downregulated expression of Bcl-2 and poly-ADP ribose polymerase. Our results emphasize a significant role of lutein as an effective inhibitor of human breast cancer cell growth that activates cell death partly through the modulation of antioxidant defense response-linked cell survival signaling markers.

MfOfd1 is crucial for stress responses and virulence in the peach brown rot fungus Monilinia fructicola

Monilinia fructicola is the most widely distributed species among the Monilinia genus in the world, and causes blossom blight, twig canker, and fruit rot on Rosaceae fruits. To date, studies on genomics and pathogenicity are limited in M. fructicola. In this study, we identified a redox-related gene, MfOfd1, which was significantly up-regulated at 1 hr after inoculation of M. fructicola on peach fruits. We used the clustered regulatory inter-spaced short palindromic repeats (CRISPR)/Cas9 system combined with homologous recombination to determine the function of the MfOfd1 gene. The results showed that the sporulation of knockdown transformants was reduced by 53% to 83%. The knockdown transformants showed increased sensitivity to H₂ O₂ and decreased virulence on peach fruits compared to the wild-type isolate Bmpc7. It was found that H₂ O₂ could stimulate the expression of MfOfd1 in the wild-type isolate. The transformants were also more sensitive to exogenous osmotic stress, such as glycerol, d-sorbitol, and NaCl, and to dicarboximide fungicides (iprodione and dimethachlon). These results indicate that the MfOfd1 gene plays an important role in M. fructicola in sporulation, oxidative response, osmotic stress tolerance, and virulence.

Novel AIEgen-Functionalized Diselenide-Crosslinked Polymer Gels as Fluorescent Probes and Drug Release Carriers

Stimuli-responsive functional gels have shown significant potential for application in biosensing and drug release systems. In this study, aggregation-induced emission luminogen (AIEgen)-functionalized, diselenide-crosslinked polymer gels were synthesized via free radical copolymerization. A series of polymer gels with different crosslink densities or tetraphenylethylene (TPE) contents were synthesized. The diselenide crosslinker in the gels could be fragmented in the presence of H2O2 or dithiothreitol (DTT) due to its redox-responsive property. Thus, the TPE-containing polymer chains were released into the aqueous solution. As a result, the aqueous solution exhibited enhanced fluorescence emission due to the strong hydrophobicity of TPE. The degradation of polymer gels and fluorescence enhancement in an aqueous solution under different H2O2 or DTT concentrations were studied. Furthermore, the polymer gels could be used as drug carriers, suggesting a visual drug release process under the action of external redox agents. The AIEgen-functionalized, diselenide-crosslinked polymer gels hold great potential in the biomedical area for biosensing and controlled drug delivery.

Electrochemical Behavior and Redox-Dependent Disassembly of Gallic Acid/FeIII Metal-Phenolic Networks

Metal-phenolic networks (MPNs) are a versatile class of organic-inorganic hybrid systems that are generating interest for applications in catalysis, bioimaging, and drug delivery. These self-assembled MPNs possess metal-coordinated structures and may potentially serve as redox-responsive platforms for triggered disassembly or drug release. Therefore, a comprehensive study of the reduction and oxidation behavior of MPNs for evaluating their redox responsiveness, specific conditions required for their disassembly, and the kinetics of metal ion release, is necessary. Using a representative MPN gallic acid-iron (GA/Fe^III) system, we conducted electrochemical studies to provide fundamental insights into the redox behavior of these MPNs. We demonstrate that GA/Fe^III is redox active, and evaluate its electrochemical reversibility, identify the oxidation state of the redox-active species, and provide information regarding the stability of the networks toward reductive stimuli and specific redox conditions required for the "on-off" or continuous release of Fe^III. Overall, through studying the redox properties of GA/Fe^III films, we advance the understanding of multifunctional iron-containing MPN platforms that may have practical significance for biologically relevant applications.

Hydrophobic Cysteine Poly(disulfide)-based Redox-Hypersensitive Nanoparticle Platform for Cancer Theranostics

Selective tumor targeting and drug delivery are critical for cancer treatment. Stimulus-sensitive nanoparticle (NP) systems have been designed to specifically respond to significant abnormalities in the tumor microenvironment, which could dramatically improve therapeutic performance in terms of enhanced efficiency, targetability, and reduced side-effects. We report the development of a novel L-cysteine-based poly (disulfide amide) (Cys-PDSA) family for fabricating redox-triggered NPs, with high hydrophobic drug loading capacity (up to 25 wt% docetaxel) and tunable properties. The polymers are synthesized through one-step rapid polycondensation of two nontoxic building blocks: L-cystine ester and versatile fatty diacids, which make the polymer redox responsive and give it a tunable polymer structure, respectively. Alterations to the diacid structure could rationally tune the physicochemical properties of the polymers and the corresponding NPs, leading to the control of NP size, hydrophobicity, degradation rate, redox response, and secondary self-assembly after NP reductive dissociation. In vitro and in vivo results demonstrate these NPs' excellent biocompatibility, high selectivity of redox-triggered drug release, and significant anticancer performance. This system provides a promising strategy for advanced anticancer theranostic applications.

Redox-responsive molecular nanoreservoirs for controlled intracellular anticancer drug delivery based on magnetic nanoparticles

A novel redox responsive controlled drug release system based on magnetic nanoparticles for efficient intracellular anticancer drug delivery is fabricated. Disulfide bonds are employed as intermediate linkers to immobilize PEI/β-CD molecules as nanoreservoirs for drug loading onto magnetic nanoparticles. The endocytotic pathway and endosomal escape of the smart controlled drug release system is proposed.