The treatment for osteoporosis involves inhibiting bone resorption and osteoclastogenesis. Glycyrrhizin (GLY) is a triterpenoid saponin glycoside known to be as the most medically efficacious component of the licorice plant. It has strong anti-inflammatory, antioxidant, and antitumor properties. We investigated the effect of GLY on osteoclastogenesis, bone resorption, and intracellular oxidative stress and its molecular mechanisms. In vitro osteoclastogenesis assays were performed using bone marrow monocytes with and without glycyrrhizin. We also evaluated the effects of glycyrrhizin on the secretion of TNF-α, IL-1β, and IL-6 in LPS-stimulated RAW 264.7 cells using ELISA. The effects of glycyrrhizin on the expression of osteoclast-related genes, such as Nfatc1, c-fos, Trap, and cathepsin K (CK), were investigated by RT-PCR. Intracellular reactive oxygen species (ROS) were detected in receptor activator of nuclear factor kappa-Β ligand (RANKL)-stimulated osteoclasts in the presence and absence of glycyrrhizin. During the inhibition of osteoclastogenesis by glycyrrhizin, phosphorylation of AMPK, Nrf2, NF-κB, and MAPK was analyzed using western blotting. Our results showed that glycyrrhizin significantly inhibited RANKL-induced osteoclastogenesis, downregulated the expression of NFATc1, c-fos, TRAP, CK, DC-STAMP, and OSCAR, and inhibited p65, p38, and JNK. Glycyrrhizin was found to significantly decrease the secretion of inflammatory cytokines (TNF-α, IL-1β, and IL-6). Additionally, glycyrrhizin reduced the formation of ROS in osteoclasts by inducing AMPK phosphorylation and nuclear transfer of NRF2, resulting in an upregulation of antioxidant enzymes, such as HO-1, NQO-1, and GCLC. In summary, we found that glycyrrhizin inhibited RANKL-induced osteoclastogenesis. It was also indicated that glycyrrhizin could reduce oxidative stress by inhibiting the MAPK and NF-κB pathways and activating the AMPK/NRF2 signaling. Therefore, glycyrrhizin may be used as an effective therapeutic agent against osteoporosis and bone resorption.

Trans-2,3-dihydro-3-hydroxyanthranilic acid (DHHA) is a cyclic β-amino acid that can be used for the synthesis of chiral materials and nonnatural peptides. The aim of this study was to accumulate DHHA by engineering Pseudomonas chlororaphis GP72, a nonpathogenic strain that produces phenazine-1-carboxylic acid and 2-hydroxyphenazine. First, the phzF deletion mutant DA1 was constructed, which produced 1.91 g/L DHHA. Moreover, rpeA and pykF were disrupted and then ppsA and tktA were co-expressed in strain DA1. The resulting strain DA4 increased DHHA concentration to 4.98 g/L, which is 2.6-fold than that of DA1. The effects of the addition of glucose, glycerol, L-tryptophan, and Feon DHHA production were also investigated. Strain DA4 produced 7.48 g/L of DHHA in the culture medium in the presence of 12 g/L glucose and 3 mM Fe, which was 1.5-fold higher than the strain in the original fermentation conditions. These results indicate the potential of P. chlororaphis GP72 as a DHHA producer.

Secondary brain damage plays an important role in Traumatic brain injury (TBI) and inhibition of this damage has benefit for TBI treatment. However, the pathogenesis of secondary brain damage remains largely unknown. Here, we tried to explore the influence of microRNAs (miRNAs) on neuron apoptosis and inflammatory response after TBI. Firstly, the miRNA expression profiles were analyzed in the cerebral cortex tissues from the TBI mice model (controlled cortical impact) using miRNA microarray. miR-23a-3p (miR-23a) attracted our attention as its suppressive effects on apoptosis and inflammation. The further results showed that miR-23a upregulation improved long-term neurological function, the neuron apoptosis, and inhibited neuroinflammation, whereas knockdown of miR-23a had an opposite result. Using etoposide-induced primary cortical neurons injury model, we found that miR-23a was decreased in this cell model and miR-23a overexpression-suppressed etoposide induced the activity of caspase 3 and the releases of inflammatory mediators in primary cortical neurons. Phosphatase and tensin homolog (PTEN), a well-known regulator of the AKT/mTOR pathway, was found to be a direct target of miR-23a in the primary cortical neurons. Most importantly, it was found that miR-23a overexpression reactivated the AKT/ mTOR pathway in TBI mice model, as demonstrated by the upregulation of phosphorylated (p-) AKT and p-mTOR. Taken together, these data indicate that miR-23a may serve as a therapeutic target for the treatment of TBI.

The fabrication approach of a membrane electrode assembly (MEA) is closely related to the performance and durability of the fuel cell. In this work, we combine reinforcement-embedding technology with a direct membrane deposition approach to prepare a gas diffusion electrode (GDE) with an expanded poly­(tetrafluoroethylene) (ePTFE)-reinforced membrane and then assemble a reinforced MEA. Compared with the traditional MEA, the reinforced MEA exhibits higher performance, especially under low-humidity operating conditions. Under H2/air operating conditions, the cell performance of the reinforced MEA reaches 724 mW cm–2 (80 °C, 100% relative humidity (RH), normal pressure). With the addition of ePTFE reinforcement, the mechanical durability of the reinforced MEA is significantly improved. After 3000 cycles of alternative dry/wet conditions, the reinforced MEA exhibited lower hydrogen permeation and less performance degradation compared with the unreinforced MEA. This work provides a new and facile way for improving the mechanical durability of MEAs.

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As a key component of proton exchange membrane fuel cells (PEMFCs), the durability of the proton exchange membranes (PEMs) directly determines the service life of the PEMFCs. As state-of-the-art PEMs, perfluorosulfonic acid (PFSA) membranes suffer from critical mechanical and chemical degradation under actual working conditions. Considering this, we present a strategy to develop highly durable PEMs by intercalating double-layer expanded polytetrafluoroethylene (ePTFE) skeletons and doping CeO 2 radical scavengers into the PFSA membranes. The results reveal that the double-layer ePTFE reinforced membranes (DR-Ms) have significantly improved mechanical properties, lower swelling rates, and superior dimensional stability compared to single-layer ePTFE reinforced membranes (SR-Ms). After the wet/dry cycle durability test, DR-Ms show a lower hydrogen crossover increase, reduced power performance attenuation, and smaller membrane impedance increase than SR-Ms. After the open-circuit voltage (OCV) durability test (ODT), DR-Ms exhibit better chemical durability behaviors (such as membrane thinning and OCV decay rates). Furthermore, the 0.5 wt % CeO 2 -doped DR-M (Ce-DR-M1) imparts a further improved chemical durability during the ODT compared with DR-Ms. In short, the developed Ce-DR-M1 with double-layer ePTFE skeletons and CeO 2 radical scavengers is a promising candidate for advanced PEMs with high mechanical and chemical durability for PEMFC applications.

Background Osteosarcoma is a primary malignant tumor that mainly affects children and young adults. Transmembrane emp24 trafficking protein 3 (TMED3) may be involved in the regulation of malignant cancer behaviors. However, the role of TMED3 in osteosarcoma remains mysterious. In this study, the potential biological function and underlying mechanism of TMED3 in progression of osteosarcoma was elaborated. Methods The expression of TMED3 in osteosarcoma was analyzed by immunohistochemical staining. The biological function of TMED3 in osteosarcoma was determined through loss-of-function assays in vitro. The effect of TMED3 downregulation on osteosarcoma was further explored by xenograft tumor model. The molecular mechanism of the regulation of TMED3 on osteosarcoma was determined by gene expression profile analysis. Results The expression of TMED3 in osteosarcoma tissues was significantly greater than that in matched adjacent normal tissues. Knockdown of TMED3 inhibited the progression of osteosarcoma by suppressing proliferation, impeding migration and enhancing apoptosis in vitro. We further validated that knockdown of TMED3 inhibited osteosarcoma generation in vivo. Additionally, ribosomal protein S15A (RPS15A) was determined as a potential downstream target for TMED3 involved in the progression of osteosarcoma. Further investigations elucidated that the simultaneous knockdown of RPS15A and TMED3 intensified the inhibitory effects on osteosarcoma cells. Importantly, knockdown of RPS15A alleviated the promotion effects of TMED3 overexpression in osteosarcoma cells. Conclusions In summary, these findings emphasized the importance of TMED3/RPS15A axis in promoting tumor progression, which may be a promising candidate for molecular therapy of osteosarcoma.

For optimal performance of proton-exchange membrane fuel cells (PEMFCs), it is necessary to optimize the interfacial contact between the proton-exchange membrane (PEM) and the catalyst layer (CL) in membrane electrode assemblies (MEAs). We have proposed a novel fabrication approach for the MEA of PEMFCs, whereby the perfluorosulfonic acid (PFSA) dispersion is coated on a substrate to form a wet film, and then a gas diffusion electrode (GDE) is placed on the wet PFSA film. After drying, separation from the substrate yields a PFSA membrane-coated electrode. In the traditional preparation method for membrane-coated electrodes, liquid PFSA ionomer suspension can easily penetrate into cracks and voids in the CL, resulting in its overfilling. This can hinder gas transmission and lead to the serious detriment of the electrochemical properties of the fuel cell. In our MEA method, the GDE floats on the wet PFSA film, avoiding excessive penetration of the liquid PFSA dispersion suspension into the CL as a result of gravity. That not only achieves excellent interfacial contact between the PEM and the CL but also prevents overfilling with the PFSA ionomer. Applying this novel MEA method, we have achieved a high peak power density of 2636 mW cm–2 [O2, 0.1 MPa, and 100% relative humidity (RH)], a reduced performance loss at a low RH, and the fabrication of extremely thin PEMs (down to 10–12 μm).