Theoretical study of the nitrogen reduction reaction catalyzed by a B-doped MoO2 six-membered ring.

In this study, two potential catalysts with double-B atom-doped atomic MoO2 (B2/MoO2) and single-B atom-doped atomic MoO2 (B/MoO2) were designed and constructed. The thermodynamics and selectivity of two catalysts in the nitrogen fixation reaction were analyzed by a DFT calculation method. The results show that B2/MoO2 shows better adsorption activation and reduction and can effectively activate nitrogen molecules by two adjacent boron atoms. It achieves an extremely low overpotential of -0.18 V and rapid NRR kinetics through an enzymatic mechanism. Therefore, B2/MoO2 is a very promising NRR candidate catalyst. This research shows that doping with diatomic B (as an active site) results in an excellent NRR catalytic activity, which provides a certain theoretical basis for the preparation of high-performance NRR catalysts.

The emerging role of deubiquitylating enzyme USP21 as a potential therapeutic target in cancer.

Although certain members of the Ubiquitin-specific peptidases (USPs) have been recognized as promising therapeutic targets for various diseases, research progress regarding USP21 has been relatively sluggish in its early stages. USP21 is a crucial member of the USPs subfamily, involved in diverse cellular processes such as apoptosis, DNA repair, and signal transduction. Research findings from the past decade demonstrate that USP21 mediates the deubiquitination of multiple well-known target proteins associated with critical cellular processes relevant to both disease and homeostasis, particularly in various cancers.This reviewcomprehensively summarizes the structure and biological functions of USP21 with an emphasis on its role in tumorigenesis, and elucidates the advances on the discovery of tens of small-molecule inhibitors targeting USP21, which suggests that targeting USP21 may represent a potential strategy for cancer therapy.

Curriculum vitae of CUG binding protein 1 (CELF1) in homeostasis and diseases: a systematic review.

RNA-binding proteins (RBPs) are kinds of proteins with either singular or multiple RNA-binding domains (RBDs), and they can assembly into ribonucleic acid-protein complexes, which mediate transportation, editing, splicing, stabilization, translational efficiency, or epigenetic modifications of their binding RNA partners, and thereby modulate various physiological and pathological processes. CUG-BP, Elav-like family 1 (CELF1) is a member of the CELF family of RBPs with high affinity to the GU-rich elements in mRNA, and thus exerting control over critical processes including mRNA splicing, translation, and decay. Mounting studies support that CELF1 is correlated with occurrence, genesis and development and represents a potential therapeutical target for these malignant diseases. Herein, we present the structure and function of CELF1, outline its role and regulatory mechanisms in varieties of homeostasis and diseases, summarize the identified CELF1 regulators and their structure-activity relationships, and prospect the current challenges and their solutions during studies on CELF1 functions and corresponding drug discovery, which will facilitate the establishment of a targeted regulatory network for CELF1 in diseases and advance CELF1 as a potential drug target for disease therapy.

Oxygen-independent alkyl radical nanogenerator enhances breast cancer therapy.

The hypoxic microenvironment of breast cancer substantially reduces oxygen-dependent free radical generation. Overexpression of glutathione (GSH) in tumor cells mitigates the impact of free radical generation. In this study, we designed and developed an oxygen-independent alkyl radical nanogenerator (copper monosulfide/2,2'-azabis(2-imidazoline) dihydrochloride@bovine serum albumin; CuS/AIPH@BSA) with spatiotemporally controlled properties and GSH consumption to enhance breast cancer therapy. We encapsulated the alkyl radical initiator, AIPH, in hollow mesoporous CuS nanoparticles with photothermal conversion effect and enveloped them in BSA. AIPH was released and decomposed to generate alkyl radicals in hypoxic breast cancer with the photothermal conversion effect of CuS under near-infrared laser irradiation. CuS consumed high GSH levels in tumor cells because it could form complex with GSH and thereby enhanced free radical treatment. In vivo and in vitro assays demonstrated the anti-tumor efficacy of the rationally designed free-radical nanogenerator in hypoxic microenvironment of breast cancer without showing systemic toxicity.

In Vivo Activation of T-Cell Proliferation by Regulating Cell Surface Receptor Clustering Using a pH-Driven Interlocked DNA Nano-Spring.

Activation of T-cell proliferation specifically in a tumor is crucial for reducing the autoimmune side effects of antitumor immunotherapy. Herein, we developed a pH-driven interlocked DNA nano-spring (iDNS) to stimulate T-cell activation in vivo in response to the low pH value in a tumor microenvironment. The interlocked structure of iDNS provide a more rigid scaffold in comparison to double-stranded DNA for ligand assembly, which can help to control the spatial distribution of ligands with more accuracy. We have demonstrated that the pH-driven reversible reconfiguration of iDNS provides a powerful way to regulate the nanoscale distribution of T-cell receptors (CD3) on the cell surface. The relatively low pH value (pH 6.5) in a solid tumor was able to drive the springlike shrinking of iDNS and induce significant T-cell proliferation, leading to an enhanced antitumor effect, thus providing a tool for specifically inducing an immune response in a tumor for immunotherapy.

Visualizing Single-Nucleotide Variations in a Nuclear Genome Using Colocalization of Dual-Engineered CRISPR Probes.

Direct visualization of single-nucleotide variation (SNV) in single cells is of great importance for understanding the spatial organization of genomes and their relationship with cell phenotypes. Herein, we developed a new strategy for visualizing SNVs in a nuclear genome using colocalization of dual-engineered CRISPR probes (CoDEC). By engineering the structure of sgRNA, we incorporated a hairpin in the spacer domain for improving SNV recognition specificity and a loop in the nonfunctional domain for localized signal amplification. Using guide probe-based colocalization strategy, we can successfully distinguish on-target true positive signals from the off-target false positives with high accuracy. Comparing with a proximity ligation-based assay (CasPLA), the probe colocalization strategy extended applicable target gene sites (the distance between two designed probes can be extended to around 200nt) and improved detection efficiency. This newly developed method provides a facile way for studying in situ information on SNVs in individual cells for basic research and clinical applications with single-molecule and single-nucleotide resolutions.

Copper-based metal-organic framework impedes triple-negative breast cancer metastasis via local estrogen deprivation and platelets blockade.

Metastasis is one of the main causes of failure in the treatment of triple-negative breast cancer (TNBC). Abnormally estrogen level and activated platelets are the key driving forces for TNBC metastasis. Herein, an "ion/gas" bioactive nanogenerator (termed as IGBN), comprising a copper-based MOF and loaded cisplatin-arginine (Pt-Arg) prodrug is developed for metastasis-promoting tumor microenvironment reprogramming and TNBC therapy. The copper-based MOF not only serves as a drug carrier, but also specifically produces Cu2+ in tumors, which catalytic oxidizing estrogen to reduce estrogen levels in situ. Meanwhile, the rationally designed Pt-Arg prodrug reduced into cisplatin to significantly promote the generation of H2O2 in the tumor, then permitting self-augmented cascade NO gas generation by oxidizing Arg through a H2O2 self-supplied way, thus blocking platelet activation in tumor. We clarified that IGBN inhibited TNBC metastasis through local estrogen deprivation and platelets blockade, affording 88.4% inhibition of pulmonary metastasis in a 4T1 mammary adenocarcinoma model. Notably, the locally copper ion interference, NO gas therapy and cisplatin chemotherapy together resulted in an enhanced therapeutic efficacy in primary tumor ablation without significant toxicity. This "ion/gas" bioactive nanogenerator offers a robust and safe strategy for TNBC therapy.

Boosting cisplatin chemotherapy by nanomotor-enhanced tumor penetration and DNA adducts formation.

Despite many nano-based strategies devoted to delivering cisplatin for tumor therapy, its clinical benefits are compromised by poor tissue penetration and limited DNA adducts formation of the drug. Herein, a cisplatin loading nanomotor based janus structured Ag-polymer is developed for cisplatin delivery of deeper tissue and increased DNA adducts formation. The nanomotor displayed a self-propelled tumor penetration fueled by hydrogen peroxide (H2O2) in tumor tissues, which is catalytically decomposed into a large amount of oxygen bubbles by Ag nanoparticles (NPs). Notably, cisplatin could elevate the intracellular H2O2 level through cascade reactions, further promote the degradation of Ag NPs accompanied with the Ag+ release, which could downregulate intracellular Cl- through the formation of AgCl precipitate, thereby enhancing cisplatin dechlorination and Pt-DNA formation. Moreover, polymer can also inhibit the activity of ALKBH2 (a Fe2+-dependent DNA repair enzyme) by chelating intracellular Fe2+ to increase the proportion of irreparable Pt-DNA cross-links. It is found that deep tissue penetration, as well as the increased formation and maintenance of Pt-DNA adducts induced by the nanomotor afford 80% of tumor growth inhibition with negligible toxicity. This work provides an important perspective of resolving chemotherapeutic barriers for boosting cisplatin therapy.

Photoactivated Self-Disassembly of Multifunctional DNA Nanoflower Enables Amplified Autophagy Suppression for Low-Dose Photodynamic Therapy.

Low-dose photodynamic therapy (PDT) holds great promise for reducing undesired patient photosensitivity in cancer treatment. Yet, its therapeutic effect is significantly affected by intracellular cytoprotective processes, such as autophagy. Here, an efficient autophagy suppressor is developed, which is a multifunctional DNA nanoflower (DNF) consisted of tumor-targeting aptamers and DNAzymes for silencing autophagy-related genes, with surface modification of low-dose photosensitizer (Ce6). It is found that the multifunctional DNF can specifically target tumor cells and generate reactive oxygen species (ROS) under light irradiation to trigger self-disassembly of DNF, enhancing the bioavailability of encoded DNAzymes, leading to amplified autophagy suppression. As a facile spatiotemporally programmable photogene therapy platform, the designed DNF is able to suppress tumor growth in vivo with a very low injection dose of Ce6 (18 µg kg-1 , around 100 times lower than the generally applied dose), representing a promising strategy for cancer therapy with safely low-dose PDT.

Wheat Ear Recognition Based on RetinaNet and Transfer Learning.

The number of wheat ears is an essential indicator for wheat production and yield estimation, but accurately obtaining wheat ears requires expensive manual cost and labor time. Meanwhile, the characteristics of wheat ears provide less information, and the color is consistent with the background, which can be challenging to obtain the number of wheat ears required. In this paper, the performance of Faster regions with convolutional neural networks (Faster R-CNN) and RetinaNet to predict the number of wheat ears for wheat at different growth stages under different conditions is investigated. The results show that using the Global WHEAT dataset for recognition, the RetinaNet method, and the Faster R-CNN method achieve an average accuracy of 0.82 and 0.72, with the RetinaNet method obtaining the highest recognition accuracy. Secondly, using the collected image data for recognition, the R2 of RetinaNet and Faster R-CNN after transfer learning is 0.9722 and 0.8702, respectively, indicating that the recognition accuracy of the RetinaNet method is higher on different data sets. We also tested wheat ears at both the filling and maturity stages; our proposed method has proven to be very robust (the R2 is above 90). This study provides technical support and a reference for automatic wheat ear recognition and yield estimation.

Nanoenabled Intracellular Calcium Bursting for Safe and Efficient Reversal of Drug Resistance in Tumor Cells.

Multidrug resistance (MDR) of a tumor is the main cause of failure of clinical chemotherapy. Herein, we report a simple, yet versatile, tumor-targeting "calcium ion nanogenerator" (TCaNG) to reverse drug resistance by inducing intracellular Ca2+ bursting. Consequently, the TCaNG could induce Ca2+ bursting in acidic lysosomes of tumor cells and then reverse drug resistance according to the following mechanisms: (i) Ca2+ specifically accumulates in mitochondria, suppressing cellular respiration and relieving tumor hypoxia, thus inhibiting P-glycoprotein biosynthesis by downregulating HIF-1α expression. (ii) Ca2+-bursting-induced respiratory depression blocks intracellular ATP production, which further leads to the P-gp incompetence. As a result, the TCaNG could decrease the IC50 of DOX to MCF-7/ADR cells by approximately 30 times and reduce the proliferation of drug-resistant tumors by approximately 13 times without obvious side effects. This simple, safe, and effective "Ca2+ bursting" strategy holds the potential for clinical application in tumor treatment.

Bioinspired Nanosponge for Salvaging Ischemic Stroke via Free Radical Scavenging and Self-Adapted Oxygen Regulating.

Either hypoxia in an acute ischemic stroke before thrombolysis or the oxygen-boost after thrombolysis cause a high level of free radicals, resulting in successive injuries to neurocytes. To treat an ischemic stroke, it is needed to scavenge free radicals, combining sequentially regulating hypoxia and oxygen-boost microenvironment. Here, we report an engineered nanosponge (Mn3O4@nanoerythrocyte-T7, MNET) that could remodel the microenvironment of a stroke by self-adapted oxygen regulating and free radical scavenging. With a long circulation time in blood due to the stealth effect of the erythrocyte and preferential accumulation in the infarct site by the assisting of T7 peptide, MNET exerts a distinct therapeutic effect in two stages of an ischemic stroke: (i) before thrombolysis, rescue neurocyte via rapid free radical scavenging and timely oxygen supply; (ii) after thrombolysis, suppress oxygen-boost via oxygen storage, as well as scavenge free radical to avoid reperfusion injury. MNET holds an attractive potential for ischemic stroke treatment via phased regulation of pathological microenvironment.

Sequential Intercellular Delivery Nanosystem for Enhancing ROS-Induced Antitumor Therapy.

Despite recent advances in enhancing photodynamic therapy efficacy, high-efficiency reactive oxygen species (ROS)-based therapy approach, especially in malignancy tumor treatment, remains challenging. Relieving the hypoxia of tumor tissue has been considered to be an attractive strategy for enhancing ROS-based treatment effect. Nevertheless, it is frequently neglected that the hypoxic regions are usually located deep in the tumors and therefore are usually inaccessible. To address these limitations, herein we constructed a sequential intercellular delivery system (MFLs/LAOOH@DOX) that consists of a membrane fusion liposomes (MFLs) doped with linoleic acid hydroperoxide (LAOOH) in the lipid bilayer and antitumor doxorubicin (DOX) encapsulated inside. In this report, LAOOH, one of the primary products of lipid peroxidation in vivo, was selected as ROS-generated agent herein, which depends on Fe2+ rather than oxygen and other external stimuli to produce ROS. Upon the enhanced permeation and retention effect, MFLs/LAOOH@DOX first fused with tumor cell membranes in the perivascular region in synchrony with selective delivery of LAOOH into the plasma membrane and the on-demand intracellular release of DOX. By hitchhiking with extracellular vesicles, LAOOH, as a cell membrane natural ingredient, spread gradually to neighboring cells and throughout the entire tumor eventually. Combined with subsequent administration of nano Fe3O4, ROS was specifically generated on the tumor cell membrane by LAOOH throughout the tumor tissues. This study offers a new method to enhance ROS-based antitumor treatment efficiency.

Ultrasmall nanostructured drug based pH-sensitive liposome for effective treatment of drug-resistant tumor.

BACKGROUND: Cancer cells always develop ways to resist and evade chemotherapy. To overcome this obstacle, herein, we introduce a programmatic release drug delivery system that imparts avoiding drug efflux and nuclear transport in synchrony via a simple nanostructured drug strategy. RESULTS: The programmatic liposome-based nanostructured drugs (LNSD) contained two modules: doxorubicin (DOX) loaded into tetrahedral DNA (TD, ~ 10 nm) to form small nanostructured DOX, and the nanostructured DOX was encapsulated into the pH-sensitive liposomes. In the in vitro and in vivo studies, LNSD shows multiple benefits for drug resistance tumor treatment: (1) not only enhanced the cellular DOX uptake, but also maintained DOX concentration in an optimum level in resistant tumor cells via nanostructure induced anti-efflux effect; (2) small nanostructured DOX efficiently entered into cell nuclear via size depended nuclear-transport for enhanced treatment; (3) improved the pharmacokinetics and biodistribution via reducing DOX leakage during circulation. CONCLUSIONS: The system developed in this study has the potential to provide new therapies for drug-resistant tumor.

The chronic hepatotoxicity assessment of the herbal formula Zishen Yutai pill.

Zishen Yutai pill (ZYP) is an oriental herbal formula, while hepatotoxicity assessment of ZYP was rarely evaluated. Therefore, our aim is to re-evaluate its hepatotoxicity in both normal and carbon tetrachloride (CCl4) induced chronic liver injury rats. In the normal model, two doses of ZYP (1.575 and 9.450 g kg-1 d-1; i.e. 1 × , 6 × clinical doses) were given orally to rats for 24 weeks. In the chronic liver injury model, 10% CCl4 was administered to rats abdominally twice a week at a dose of 5 mL kg-1 for 12 consecutive weeks. Administration time started from 4 weeks after the beginning of CCl4 treatment. Toxicological parameters included mortality, body weight, food consumption, clinical signs, biochemical parameters, gross observation, organ weight, necropsy findings and histopathology were monitored. In the normal model, we found no any mortality or abnormality in clinical signs, relative liver weight, biochemical parameters and histopathology in ZYP treatment groups. In the chronic liver injury model, liver damage related parameter such as ALT was elevated at the high dose of ZYP treatment in contrast to the CCl4-treated group (P < 0.01). In histopathological assessment, there were no significant difference between ZYP treatment groups and CCl4-treated group. No observed adverse effect on livers were established for 9.450 g kg-1 d-1 ZYP in the normal rats and 9.450 g kg-1 d-1 ZYP in the injury rats.

A Multi-Functional Tumor Theranostic Nanoplatform for MRI Guided Photothermal-Chemotherapy.

PURPOSE: To develop a multi-functional theranostic nanoplatform with increased tumor retention, improving antitumor efficacy and decreased side effects of chemotherapy drugs. METHODS: GO@Gd nanocomposites was synthesized via decorating gadolinium (Gd) nanoparticles (GdNP) onto graphene oxide (GO), and then functionalized by polyethylene glycol (PEG2000), folic acid (FA), a widely used tumor targeting molecule, was linked to GO@Gd-PEG, finally, doxorubicin (DOX) was loaded onto GO@Gd-PEG-FA and obtained a tumor-targeting drug delivery system (GO@Gd-PEG-FA/DOX). GO@Gd-PEG-FA/DOX was characterized and explored its theranostic applications both in a cultured MCF-7 cells and tumor-bearing mice. RESULTS: GO@Gd-PEG-FA/DOX could efficiently cross the cell membranes, lead to more apoptosis and afford higher antitumor efficacy without obvious toxic effects to normal organs owing to its prolonged blood circulation and 7.6-fold higher DOX uptake of tumor than DOX. Besides, GO@Gd-PEG-FA/DOX also served as a powerful photothermal therapy (PTT) agent for thermal ablation of tumor and a strong T1-weighted contrast agent for tumor MRI diagnosis. The multi-functional nanoplatform also could selectively kill cancer cells in highly localized regions via the excellent tumor-targeting and MRI guided PTT abilities. CONCLUSIONS: GO@Gd-PEG-FA/DOX exhibited excellent photothermal-chemotherapeutic efficacy, tumor-targeting property and tumor diagnostic ability.

Smart nanocomposite hydrogels based on azo crosslinked graphene oxide for oral colon-specific drug delivery.

A safe and efficient nanocomposite hydrogel for colon cancer drug delivery was synthesized using pH-sensitive and biocompatible graphene oxide (GO) containing azoaromatic crosslinks as well as poly (vinyl alcohol) (PVA) (GO-N=N-GO/PVA composite hydrogels). Curcumin (CUR), an anti-cancer drug, was encapsulated successfully into the hydrogel through a freezing and thawing process. Fourier transform infrared spectroscopy, scanning electron microscopy and Raman spectroscopy were performed to confirm the formation and morphological properties of the nanocomposite hydrogel. The hydrogels exhibited good swelling properties in a pH-sensitive manner. Drug release studies under conditions mimicking stomach to colon transit have shown that the drug was protected from being released completely into the physiological environment of the stomach and small intestine. In vivo imaging analysis, pharmacokinetics and a distribution of the gastrointestinal tract experiment were systematically studied and evaluated as colon-specific drug delivery systems. All the results demonstrated that GO-N=N-GO/PVA composite hydrogels could protect CUR well while passing through the stomach and small intestine to the proximal colon, and enhance the colon-targeting ability and residence time in the colon site. Therefore, CUR loaded GO-N=N-GO/PVA composite hydrogels might potentially provide a theoretical basis for the treatment of colon cancer with high efficiency and low toxicity.

[Phytoestrogens in application prospect of treatment of myocardial ischemia/reperfusion injury].

Reperfusion is the most effective treatment for acute myocardial infarction, markedly reducing mortality and morbidity. Reperfusion however induces necrotic and apoptotic damages to cardiomyocytes, that were viable prior to reperfusion, a process called myocardial ischemia/reperfusion injury(MI/RI). Over the past 30 years, hundreds of experimental interventions (both pharmacologic and nonpharmacologic) have been reported to protect the ischemic myocardium in experimental animals; however, with the exception of early reperfusion, none has been translated into clinical practice. The population-based survey assessed men have about twice the total incidence of morbidity and mortality of women, and the sex gap in morbidity tends to diminish after age 45 years. So hormone replacement therapy (HRT) is given to treat the MI/RI, and lots of studies shows that the side effect is greater for estrogen, compared with phyestrogen. In this article, we review the important pathogenesis of myocardial ischemia reperfusion injury, the prevention and limitations of HRT. And we highlight the mechanism of phyestrogens treatment the MI/RI in experiment. The aim is to provide the theoretically new way of develop the safe and effective products for the researchers.

Pharmacokinetics and bioequivalence evaluation of two oral formulations of cotrimoxazole tablets in healthy Chinese volunteers under fasting conditions.

This bioequivalence study was conducted to evaluate two oral formulations of cotrimoxazole tablets in healthy Chinese subjects. All 26 subjects recruited to this study were randomly and evenly classified into two groups and received a single dose (sulfamethoxazole: 400 mg and trimethoprim: 80 mg) of test cotrimoxazole tablets (generic drug) or reference cotrimoxazole tablets (branded drug). After a 7-day washout period, these subjects received one dose of reference drug or test drug. Blood samples were collected from participants before and up to 48 h after dosing to assess the concentration of sulfamethoxazole (SMX) and trimethoprim (TMP) in plasma and a plasma concentration-time curve was drawn. Then, the pharmacokinetics parameters were calculated accordingly. Our data revealed that there were no significant differences observed in the maximum plasma concentration (Cmax), area under the curve from time 0 to the last measurable concentration (AUC0-t), and area under the curve from time 0 to infinity (AUC0-∞) between the two formulations. For SMX, the 90% confidence intervals (CI) of the geometric mean ratio for Cmax, AUC0-t, and AUC0-∞ were 104.03-113.92%, 100.46-103.70%, and 100.41-103.81%, respectively. Similarly, for Trimethoprim (TMP), the 90% CI ranged from 98.54 to 106.95% for Cmax, from 99.31 to 107.68% for AUC0-t, and from 99.49 to 107.55% for AUC0-∞. Importantly, all these 90% CI values fell within the range of 80.00-125.00%, indicating that the test drug is bioequivalent to the reference drug. Furthermore, throughout the entire trial, no suspected serious adverse events were reported, indicating the safety profile of the newly developed generic cotrimoxazole. In summary, our study demonstrates that the newly developed generic formulation of cotrimoxazole is bioequivalent to the branded formulation under fasting conditions.