Resveratrol inhibits K(v)2.2 currents through the estrogen receptor GPR30-mediated PKC pathway.

Resveratrol (REV) is a naturally occurring phytoalexin that inhibits neuronal K⁺ channels; however, the molecular mechanisms behind the effects of REV and the relevant α-subunit are not well defined. With the use of patch-clamp technique, cultured cerebellar granule cells, and HEK-293 cells transfected with the K(v)2.1 and K(v)2.2 α-subunits, we investigated the effect of REV on K(v)2.1 and K(v)2.2 α-subunits. Our data demonstrated that REV significantly suppressed Kv2.2 but not Kv2.1 currents with a fast, reversible, and mildly concentration-dependent manner and shifted the activation or inactivation curve of Kv2.2 channels. Activating or inhibiting the cAMP/PKA pathway did not abolish the inhibition of K(v)2.2 current by REV. In contrast, activation of PKC with phorbol 12-myristate 13-acetate mimicked the inhibitory effect of REV on K(v)2.2 by modifying the activation or inactivation properties of Kv2.2 channels and eliminated any further inhibition by REV. PKC and PKC-α inhibitor completely eliminated the REV-induced inhibition of K(v)2.2. Moreover, the effect of REV on K(v)2.2 was reduced by preincubation with antagonists of GPR30 receptor and shRNA for GPR30 receptor. Western blotting results indicated that the levels of PKC-α and PKC-ß were significantly increased in response to REV application. Our data reveal, for the first time, that REV inhibited K(v)2.2 currents through PKC-dependent pathways and a nongenomic action of the oestrogen receptor GPR30.

Improving the Behavioral Intention of Continuous Online Learning Among Learners in Higher Education During COVID-19.

The COVID-19 pandemic caused colleges and universities to rely heavily on online learning to continue knowledge dissemination to learners. This study used the second-generation model of unified theory of acceptance and use of technology (UTAUT2) to comprehensively analyze the mediating effects of self-efficacy, which affects learners' effective use of online tools for learning, and capability of metacognition and self-regulation, which can independently adjust learning progress into the UTAUT2 model, on the learner's willingness to continue online learning [i.e., their behavioral intention (BI)] by constructing a UTAUT2-based e-learning model. This study administered questionnaires to undergraduates in universities in East China to collect data. The effects of performance expectancy, effort expectancy (EE), social influence (SI), and facilitating conditions (FCs), hedonic motivation (HM), price value (PV), and habits on BI (directly or through mediators) were analyzed through data analysis and structural equation modeling, and the UTAUT2-based e-learning model was accordingly modified. The results indicated that the self-efficacy enhanced the effects of EE, SI, FCs, HM, and PV on learners' BI; that metacognition and self-regulation (MS) capabilities enhanced the effects of EE on learners' BI; and that habits had a direct and strong effect on BI. This study also provided some suggestions to enhance higher education learners' willingness to continue online learning, such as improving social recognition and support, careful design of teaching content, easy-to-use technology, financial support. These results and suggestions may guide colleges and universities in conducting, continuing, or enhancing online education, particularly as the pandemic continues.

Biomaterials for local drug delivery in central nervous system.

The central nervous system (CNS) is a vital part of human body which coordinate the actions by transmitting signals. Because of the existence of the blood-brain barrier and the blood-spinal cord barrier, diseases in CNS can hardly be directly intervened by non-invasive methods. While systemic delivery usually requires extravagant drug dosage and leads into toxicity in unexpected tissues, local drug delivery in CNS tissues provides a solution for the problems of physiological barriers and systematic side effects. Biomaterials are applied in local drug delivery system (LDDS) for CNS disease therapy with aims of tuning the drug release property and improving bioavailability, solubility, stability and safety of pharmaceutics. The indispensable importance and distinct physiological structure of cerebrospinal area bring about challenges to biomaterials in LDDS. Thus, properties of drug delivery systems are necessitated with prudently concern. In this review, the development of LDDS utilizing biomaterials will be presented, including sustained release, local parameter-responsible release, and regional cell-selective active targeting release. Studies on biomaterials employed as pharmaceuticals will give rise to a more efficacious method and the better understanding of LDDS design in CNS.

Transplantation of BDNF Gene Recombinant Mesenchymal Stem Cells and Adhesive Peptide-modified Hydrogel Scaffold for Spinal Cord Repair.

INTRODUCTION: Mesenchymal Stem Cells (MSCs) are promising candidates for nerve tissue engineering. Brain Derived Neurotrophic Factor (BDNF) secreted by MSCs can function to increase neural differentiation and relieve inflammation response. Gene transfection technology is an efficient strategy to increase the secretion levels of cytokines and enhance cellular functions. However, transfection and in vivo gene expression of environmentally sensitive stem cells have been one of the most challenging subjects due to the requirement in both safety and transfection efficiency. In this study, gene transfection technology was applied to prepare BDNF gene recombinant MSCs based on our previously reported liposomal vector ScreenFect® A. To improve cellular survival and gene expression after in situ implantation of MSCs, an adhesive peptide modified hydrogel scaffold was constructed using hyaluronic acid. The scaffold was optimized and modified with an adhesive peptide PPFLMLLKGSTR. The transfected MSCs exhibited improved cellular survival and sustained gene expression in the three-Dimentional (3D) scaffold in vitro. Compared to untransfected MSCs, gene recombinant MSCs effectively improved spinal tissue integrity, inhibited glial scar formation and alleviated inflammatory response. These effects were found discounted when cells were implanted without the scaffold. CONCLUSION: The study developed a promising implantation system for therapy of severe spinal cord injury and provided the first understanding of Screenfect® A about its functions on stem cell therapy for nerve tissue repair as well as three-dimentional gene expression.

α-chymotrypsin activated and stabilized by self-assembled polypseudorotaxane fabricated with bis-thiolated poly(ethylene glycol) and α-cyclodextrin: Spectroscopic and mechanistic analysis.

The self-assembled polypseudorotaxane (PPRX) fabricated with bis-thiolated poly(ethylene glycol) (PEG) and α-cyclodextrin (α-CyD) acted as an activator for α-chymotrypsin (CT) and retained the activity of CT for a long time up to 7days. The stabilization mechanism was studied, and the interaction between CT and PPRX was analyzed by using circular dichroism, fluorescence spectra and X-ray powder diffraction (XRD). The bis-thiolated PEG and its assembled PPRX with α-CyD exhibited the interaction with the C-terminal region of the CT's B-chain probably through PEGylation of the surface disulfide bridge of CT. It caused the aromatic chromophores more exposed to the hydrophilic microenvironment, leading to conformational variation of CT that was revealed by spectroscopic analysis. It rendered the peptide chains in a more flexible and active state. As a comparison, the non-thiolated components could not decorate the surface of CT and performed almost no effect on its stability, which demonstrated that the decoration of the surface disulfide bridge was a key factor in retaining the activity of CT. Due to the activation and stabilization effect, bis-thiolated PEG/α-CyD PPRX was an excellent soft-immobilized carrier for CT, and provided an intriguing method for enzyme's stabilization.