Nrf2 differentially regulates osteoclast and osteoblast differentiation for bone homeostasis.

Nuclear factor erythroid-derived factor 2-related factor 2 (Nrf2) is a master regulator of antioxidant response and protects cells from excessive oxidative stress. Nrf2 emerges as a prospective therapeutic target for metabolic bone disorders, in which the balance between osteoblastic bone formation and osteoclastic bone resorption is disrupted. However, the molecular mechanism through which Nrf2 modulates bone homeostasis remains unclear. In this study, we compared the differences in Nrf2-mediated antioxidant response and ROS regulation in osteoblasts and osteoclasts, both in vitro and in vivo. Findings indicated a close connection between the Nrf2 expression and its related antioxidant response with osteoclasts than osteoblasts. We next pharmacologically manipulated the Nrf2-mediated antioxidant response during osteoclast or osteoblast differentiation. Nrf2 inhibition enhanced osteoclastogenesis, while its activation suppressed it. In contrast, osteogenesis decreased irrespective of whether Nrf2 was inhibited or activated. These findings highlight the distinct ways in which the Nrf2-mediated antioxidant response regulates osteoclast and osteoblast differentiation, thereby contributing to the development of Nrf2 targeted therapies for metabolic bone diseases.

Self-Assembled Reduced Graphene Oxide-TiO2 Thin Film for the Enhanced Photocatalytic Reduction of Cr(VI) Under Simulated Solar Irradiation.

In this study, reduced graphene oxide-TiO2 (RGO-TiO2) thin film was prepared by a simple self-assembly method at the gas/liquid interface. The as-prepared thin films were characterized by X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM), UV-visible-diffuse reflectance spectroscopy (UV-vis-DRS) and X-ray photoelectron spectroscopy (XPS). Photocatalytic activities of TiO2 and RGO-TiO2 thin film were investigated via the reduction of Cr(VI) under simulated solar light and visible light (λ > 420 nm) irradiation. The results showed that the RGO-TiO2 thin film exhibited remarkably enhanced activity for photoreduction of Cr(VI) under simulated sunlight or visible light irradiation, with a reaction rate constant of 5.7 times greater than that of pure TiO2 thin film. The main reason for enhanced photocatalytic activity is that introduction of RGO can restrain the recombination of photogenerated electron-hole pairs and reduce the aggregation of TiO2 NPs. The effects of different reaction parameters such as irradiation time, irradiation source, pH values, catalyst dosage and initial Cr(VI) concentration were investigated in detail. The highest photoreduction efficiency of Cr(VI) was achieved and the reduction rate constant k was 0.0189 min-1 during the reduction of 0.5 mg L-1 of Cr(VI) with 10 cm² RGO-TiO2 thin film at pH 2.0 and 293 K. Moreover, different scavengers were also added in the photoreduction of Cr(VI) system to identify the reactive species. Based on the results of the present study, a possible mechanism of photoreduction on RGO-TiO2 thin film under simulated solar light was proposed. Overall, this study provides a novel approach to efficiently photoreduction of Cr(VI) by RGO-TiO2 thin film.

Preparation and Characterization of Biomass Tannin-Based Flexible Foam Insoles for Athletes.

The exploitation of bio-based foams implies an increase in the use of renewable biological resources to reduce the rapid consumption of petroleum-derived resources. Both tannins and furfuryl alcohol are derived from forestry resources and are, therefore, considered attractive precursors for the preparation of tannin-furanic foams. In addition, toughening modification of tannin-furanic foams using polyvinyl alcohol (PVOH) results in a more flexible network-like structure, which imparts excellent flexibility to the foams, whose relative properties are even close to those of polyurethane foams, which are the most used for fabrication of insoles for athletes. In addition, the addition of PVOH does not affect the thermal insulation properties of the foams by testing the thermal conductivity, resilience, and elongation at break, while reducing the brittleness of the samples and improving the mechanical properties. Also, the observation of the morphology of the foam shows that the compatibility between PVOH and tannin-furanic resin is good, and the cured foam does not show fragmentation and collapse, while the bubble pore structure is uniform. The developed flexible foam derived from biomass resources endows the foam with good thermal insulation properties and high mechanical properties, and the samples exhibit suitable physical parameters to be used as flexible insoles for athletes.

Dynamic tagging to drive arginine nano-assembly to metabolically potentiate immune checkpoint blockade therapy.

L-arginine metabolism is essential for the activation, survival, and effector function of the T lymphocytes and critical in eliminating tumors via T-cell-mediated immunotherapy, such as immune checkpoint blockade (ICB). Unfortunately, efficient delivery of hydrophilic L-arginine to the tumor microenvironment (TME) has met tremendous difficulties because of the limited loading efficacy and rapid diffusion. Inspired by the small-molecule prodrug nanoassemblies with ultrahigh drug-loading, we screen out aromatic aldehydes compounds to be used as dynamic tags to decorate L-arginine (reversible imine). Nano-Arginine (ArgNP, 104 nm) was created based on dynamic tag-mediated self-assembly. Molecular dynamics simulations indicate that the driving force of this self-assembly process is intermolecular hydrogen bonds, π-π stacking, and cation-π interactions. Notably, ArgNP metabolic synergy with anti-PD-L1 antibody (aPDL1) can promote tumor-infiltrating T cells (3.3-fold than aPDL1), resulting in a tumor inhibition ratio of 2.6-fold than aPDL1. Besides, such a strategy efficiently reduces the myeloid-derived suppressor cells, increases the M1-macrophages against the tumor, and induces the production of memory T cells. Furthermore, this synergistic therapy effectively restrains lung metastasis and prolongs mouse survival (60% survival ratio). The study highlights the dynamic tags strategy with facility and advance to deliver L-arginine that can metabolically promote ICB therapy.

Customized blood-brain barrier shuttle peptide to increase AAV9 vector crossing the BBB and augment transduction in the brain.

Recombinant adeno-associated virus (rAAV) vectors have been widely used as favored delivery vehicles for the treatment of inherited diseases in clinical trials, including neurological diseases. However, the noninvasive systemic delivery of rAAV to the central nervous system is severely hampered by the blood-brain barrier (BBB). Several approaches have been exploited to enhance AAV vector brain transduction after systemic administration, including genetic modification of AAV capsids and physical methods. However, these approaches are not always predictive of desirable outcomes in humans and induce complications. It is imperative to explore novel strategies to increase the ability of AAV9 to cross the BBB for enhanced brain transduction. Herein, we have conducted a combinatorial in vivo/in vitro phage display library screening in mouse brains and purified AAV9 virions to identify a customized BBB shuttle peptide, designated as PB5-3. The PB5-3 peptide specifically bound to AAV9 virions and enhanced widespread transduction of AAV9 in mouse brains, especially in neuronal cells, after systemic administration. Further study demonstrated that systemic administration of AAV9 vectors encoding IDUA complexed with PB5-3 increased the phenotypic correction in the brains of MPS I mice. Mechanistic studies revealed that the PB5-3 peptide effectively increased AAV9 trafficking and transcytosis efficiency in the human BBB model hCMEC/D3 cell line but did not interfere with AAV9 binding to the receptor terminal N-linked galactosylated glycans. Additionally, the PB5-3 peptide slowed the clearance of AAV9 from blood without hepatic toxicity. This study highlights, for the first time, the potential of this combinatorial approach for the isolation of peptides that interact with specific AAV vectors for enhanced and targeted AAV transduction. This promising approach will open new combined therapeutic avenues and shed light on the potential applications of peptides for the treatment of human diseases in future clinical trials with AAV vector-mediated gene delivery.

Characterization of Esterase Genes Involving Malathion Detoxification and Establishment of an RNA Interference Method in Liposcelis bostrychophila.

Esterases (ESTs) play important roles in metabolizing various physiologically endogenous and exogenous compounds, and various environmental xenobiotics in insects. The psocid, Liposcelis bostrychophila is a major pest of stored products worldwide and rapidly develops resistance to commonly insecticides. However, the involvement of ESTs in insecticide metabolization and the application of RNAi approach in psocids have not been well elucidated. In this study, we characterized four LbEST genes and investigated the transcriptional levels of these genes at different developmental stages and under different insecticides exposures to assess their potential roles in response to insecticides. The four LbESTs contain a catalytic triad (Ser-His-Glu) linked to an oxyanion hole and acyl pocket involved in substrate stabilization during its hydrolysis. Synergism observed with the esterase-inhibitor DEF suggests the involvement of esterases in malathion detoxification. LbESTs were expressed during the whole of developmental stages, but predominant abundance in the first nymphal instar and adult stage. The mRNA level of three LbEST genes (except for LbEST4) was induced (1.29- to 5.60 fold) in response to malathion or deltamethrin exposures, indicating that these esterases are involved in the detoxification process. Silencing of LbEST1, LbEST2 or LbEST3 through dsRNA feeding led to a higher mortality of psocids upon the malathion treatment compared to controls (1.83 to 2.69-fold), demonstrating that these esterase genes play roles in malathion detoxification in L. bostrychophila. Our study provides new evidence for understanding of the function and regulation mechanism of esterases in L. bostrychophila in insecticide detoxification. The current study also suggests that the present RNAi method could be applied for gene functional studies in psocids.

Isothermal kinase-triggered supramolecular assemblies as drug sensitizers.

Protein kinases, the main regulators of a vast map of cellular processes, are the most attractive targets in drug discovery. Despite a few successful examples of protein kinase inhibitors, the drug discovery strategy of downregulating protein kinase activity has been quite limited and often fails even in animal models. Here, we utilize protein kinase A (PKA) activity to design PKA-triggered supramolecular assemblies with anticancer activities. Grafting a suitable peptide to PNIPAM raises the critical temperature of the LCST polymer above body temperature. Interestingly, the corresponding phosphorylated polymer has a critical temperature below body temperature, making this peptide-appended PNIPAM a suitable polymer for the PKA-triggered supramolecular assembly process. PKA-triggered assembly occurs selectively in PKA-upregulated MCF-7 cells, which disturbs the cytoskeleton and sensitizes cancer cells against doxorubicin. The chemosensitization is also observed in vivo to identify effective tumor inhibitors with satisfactory biocompatibility. Overall, this phosphorylation-induced (in principle, PKA-catalyzed) supramolecular assembly opens up a promising chemotherapy strategy for combating kinase-upregulated cancer.

[A clinical evaluation on the stability of orthodontic mini-implants using resonance frequency analysis].

PURPOSE: To evaluate the stability of mini-implant by resonance frequency analysis and to determine the optimal loading timing of orthodontic force. METHODS: Fourteen orthodontic patients who had upper first premolars extraction and needed mini-implants to reinforce the anchorage were enrolled in this study. The patients were divided into 2 groups: delay-loading group and selective-loading group. A joined head mini-implant was inserted in the buccal interradicular area on each side of maxilla for each patient and 28 mini-implants in total were used. Osstell resonance frequency device was used to measure the ISQ (implant stability quotients) value. The measurements were performed immediately after the implant insertion and weekly afterwards until week 16. After the ISQ value was stable, orthodontic force of 150g was loaded on the mini-implants in selective-loading group. The same level of force was applied in delay-loading group at week 12. The data was analyzed by one-way ANOVA and t test using SPSS 19.0 software package. RESULTS: Twenty-three mini-implants were stable during the study. Twelve unloading mini-implants in delay-loading group showed maximal ISQ values immediately after insertion and at week 1 (21.48 ± 5.25). The ISQ values decreased gradually from week 2 to week 5 and reached a plateau after week 6 (11.26 ± 3.36). Eleven mini-implants survived in selective-loading group were then loaded at week 6. There were no significant differences of ISQ values in loading and unloading mini-implants after 6 weeks. The remaining 5 mini-implants were loosing during the first 4 weeks, which showed a significant lower initial ISQ values compared to the successful implants. CONCLUSIONS: The stability of mini-implants decreases 1 week after insertion and maintains after 6 weeks. Orthodontic loading after week 6 has no influence on the stability. Lower initial stability is an important factor for the failure of mini-implants.