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QO-58 lysine (QO-58L) as a new potassium channel opener, reported to have a potential activity to cure neuropathic pain. The aim of this research is to develop and validate a high-performance liquid chromatography with tandem spectrometry (LC-MS/MS) method for the quantification of QO-58L in rat urine, feces and bile. In addition, analyze and identify the metabolites in urine and bile. The assay for this compound in samples detected with multiple reaction monitoring mode (MRM), and take nimodipine as internal standards (IS). To better understand the biotransformation of QO-58L, metabolites in urine and bile were identified by using ultra high performance liquid chromatography tandem quadrupole/time of flight mass spectrometry (UHPLC-Q-TOF-MS) in the positive and negative ion mode. Urine, feces and bile were quantified by three new methods. The results showed that: QO-58L was mainly eliminated through fecal route (92.94%), a small amount of it via biliary excretion (2.05%), and rarely through urinary excretion (0.024%). As a result, there are 11 metabolites were identified, including 8 phase I metabolites resulting from elimination, hydroxylation and dihydroxylation, and 3 phase II metabolites originating from sulfation, N -acetylcysteine conjugation and glucuronidation. Furthermore, the newly discoveries of excretion and metabolism significantly expanded our understanding and was going to be greatly helpful for QO-58L's further pharmacokinetic study in vivo. [ABSTRACT FROM AUTHOR]

Nucleic acid modifications have attracted increasing attention in recent years since they have been found to be related to a number of diseases including cancer. Previous studies have shown that the early development of endometrial cancer (EC) is often accompanied by changes in methylation levels of related genes, and the expression of related proteins that regulate reactive oxygen species (ROS) shows significant differences in EC cells and tissues. However, it has not been reported whether nucleic acid modifications related to methylation or ROS can serve as biomarkers for EC. Accurate quantification of these nucleic acid modifications still has challenges because their amounts in urine are very low and the interferences in urine are complicated. In this study, a novel dispersive solid-phase extraction (DSPE) method based on chitosan-carbon nanotube-Al2O3 (CS-CNT-Al2O3) has been established for the analysis of 5-hydroxymethyluracil (5 mU), 5-methyl-2′-deoxycytidine (5-mdC), 5-hydroxymethyl-2′-deoxycytidine (5-hmdC), 5-formyl-2′-deoxycytidine (5-fdC), and 8-hydroxy-2′-deoxyguanosine (8-OHdG) in EC patient urine samples coupled with UHPLC-QE-Orbitrap-MS/MS and HPLC–UV. Firstly, the synthesis of the CS-CNT-Al2O3 nanocomposite was conducted by a sono-coprecipitation method and was characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and Fourier transform infrared (FTIR). Under the optimal extraction conditions of DSPE, we successfully quantified 5 mU, 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG in urine samples from 37 EC patients and 39 healthy controls. The results showed that there were significant differences in the levels of 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG in EC patients compared to the healthy control group. The receiver operator characteristic (ROC) curve analysis was carried out to evaluate the potential of 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG to distinguish EC patients from healthy volunteers. The area under the curve (AUC) for 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG was 0.7412, 0.667, 0.8438, and 0.7981, respectively. It indicated that 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG had certain potential in distinguishing between EC patients and healthy volunteers and they could act as potential non-invasive biomarkers for early diagnosis of EC. Moreover, the present study would stimulate investigations of the effects of nucleic acid modifications on the initiation and progression of EC. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "A new methodology to reveal potential nucleic acid modifications associated with the risk of endometrial cancer through dispersive solid-phase extraction coupled with UHPLC-QE-Orbitrap-MS/MS and HPLC-UV." The correction addresses an error in Table 4 of the original article, where the order of literature numbers in column 8 was incorrect. The correct order should be "32, 33, 34, 35, 36" instead of "28, 29, 30, 31, 32." The correction has been made to the original article. The document also includes a note from the publisher stating their neutrality regarding jurisdictional claims and institutional affiliations. [Extracted from the article]

Introduction: Voltage-gated Kv7/M potassium channels play an essential role in the control of membrane potential and neuronal excitability. Fangchinoline, a bisbenzylisoquinoline alkaloid, displays extensive biological activities including antitumor, anti-inflammatory, and antihypertension effects. In this study, we investigated the effects of fangchinoline on Kv7/M channels. Methods: A perforated whole-cell patch technique was used to record Kv7 currents from HEK293 cells and M-type currents from mouse dorsal root ganglion (DRG) neurons. Results: Fangchinoline inhibited Kv7.2/Kv7.3 currents in a concentration-dependent manner, with an IC50 of 9.5 ± 1.2 μM. Fangchinoline significantly inhibited Kv7.1, Kv7.2, Kv7.3, Kv7.4, and Kv7.3/Kv7.5 channels without selective effects. Furthermore, fangchinoline significantly slowed the activation of Kv7.1-Kv7.5 channels and inhibited native M-channel currents of DRG neurons. Conclusion: Taken together, our findings indicate that fangchinoline concentration-dependently inhibited Kv7/M channel currents. [ABSTRACT FROM AUTHOR]

Nowadays, significant progress has been made in the development of selective histone deacetylase 6 (HDAC6) inhibitors, exerting great potential in the treatment of various malignant tumors and neurodegenerative diseases. Previously, selective inhibitory activities of HDAC inhibitors were generally considered sensitive to the interactions between the Cap group and the binding site of HDAC6, and a large number of selective HDAC6 inhibitors have been designed and synthesized based on the strategy. However, some inhibitors without Cap group could also exhibit excellent potency and selective inhibition towards HDAC6, and in this study, BRD9757 and compound 8, as capless selective HDAC6 inhibitors, were selected as molecular probes to explore the difference of their binding interactions in HDAC1&6. Through the analysis of binding‐free energies and conformational rearrangements after 1 μs molecular dynamics simulation, it could be learned that although the residues in the binding site remained highly consistent, the binding mechanisms of BRD9757 and compound 8 in HDAC1&6 were different, which will provide valuable hints for the discovery of novel selective HDAC6 inhibitors. [ABSTRACT FROM AUTHOR]

Background: Small interfering RNA (siRNA) is utilized as a potent agent for cancer therapy through regulating the expression of genes associated with tumors. While the widely application of siRNAs in cancer treatment is severely limited by their insufficient biological stability and its poor ability to penetrate cell membranes. Targeted delivery systems hold great promise to selectively deliver loaded drug to tumor site and reduce toxic side effect. However, the elevated tumor interstitial fluid pressure and efficient cytoplasmic release are still two significant obstacles to siRNA delivery. Co-delivery of chemotherapeutic drugs and siRNA represents a potential strategy which may achieve synergistic anticancer effect. Herein, we designed and synthesized a dual pH-responsive peptide (DPRP), which includes three units, a cell-penetrating domain (polyarginine), a polyanionic shielding domain (ehG)n, and an imine linkage between them. Based on the DPRP surface modification, we developed a pH-responsive liposomal system for co-delivering polo-like kinase-1 (PLK-1) specific siRNA and anticancer agent docetaxel (DTX), D-Lsi/DTX, to synergistically exhibit anti-tumor effect. Results: In contrast to the results at the physiological pH (7.4), D-Lsi/DTX lead to the enhanced penetration into tumor spheroid, the facilitated cellular uptake, the promoted escape from endosomes/lysosomes, the improved distribution into cytoplasm, and the increased cellular apoptosis under mildly acidic condition (pH 6.5). Moreover, both in vitro and in vivo study indicated that D-Lsi/DTX had a therapeutic advantage over other control liposomes. We provided clear evidence that liposomal system co-delivering siPLK-1 and DTX could significantly downregulate expression of PLK-1 and inhibit tumor growth without detectable toxic side effect, compared with siPLK-1-loaded liposomes, DTX-loaded liposomes, and the combinatorial administration. Conclusion: These results demonstrate great potential of the combined chemo/gene therapy based on the multistage pH-responsive codelivery liposomal platform for synergistic tumor treatment. [ABSTRACT FROM AUTHOR]

Febrile seizure is a common neurologic disorder with limited treatment occurring in infants and children under the age of five. Jujuboside B (JuB) is a main bioactive saponin component isolated from the Chinese anti-insomnia herbal medicine Ziziphi Spinosae Semen (ZSS), seed of Ziziphus jujuba Mill , which has been proved to exhibit neuroprotective effects recently. In this study, we aimed at elucidating the effect of JuB on suppressing febrile seizure and the potential mechanisms. Electroencephalogram (EEG) recording was used to monitor the severity of febrile seizures. The JuB in the brain was identified by mass spectrometry. Neuronal excitability was investigated using patch clamp. JuB (30 mg/kg) significantly prolonged seizure latency and reduced the severity in hyperthermia-induced seizures model mice. Hippocampal neuronal excitability was significantly decreased by JuB. And JuB significantly reduced the excitatory synaptic transmission mediated by α-amino-3-hydroxy-5-methyl-4-iso-xazolepropionic acid receptor (AMPAR), including evoked excitatory postsynaptic currents (eEPSCs), and miniature EPSCs (mEPSCs) in hippocampal neurons. Furthermore, JuB also significantly inhibited recombinant GluA1 and GluA2 mediated AMPA current in HEK293 cell and decreased the upregulation of [Ca2+] i induced by AMPA in primary cultured cortex neurons. JuB suppressed the excitability of hippocampal neurons by inhibiting the activity of AMPAR and reducing the intracellular free calcium, thereby relieving febrile seizures. [Display omitted] • Jujuboside B (JuB) could relieve febrile seizures in mice model. • JuB suppressed the excitability of hippocampal neurons. • JuB inhibited AMPAR currents, and the synaptic transmission mediated by AMPAR. • JuB reduced the intracellular free calcium in cultured primary neuron. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nephrotoxicity induced by the arsenic trioxide is often overlooked and the underlying mechanisms remain poorly understood. • Network pharmacology approach was utilized to analyze the potential targets and possible biological mechanisms of 6-gingerol against nephrotoxicity. • 6-gingerol ameliorates nephrotoxicity through antioxidant, anti-inflammatory and anti-apoptotic properties. • The mechanism may be related to the inhibition of MAPKs signaling pathway. Nephrotoxicity induced by the chemotherapeutic drug arsenic trioxide (ATO) is often overlooked, and the underlying mechanisms remain poorly understood. Based on network pharmacology and experimental validation, this study investigates the protection of 6-gingerol (6G) against ATO-induced nephrotoxicity and the potential mechanisms. We screened and collected 6G and disease-related targets and then imported the interaction targets into a String database to construct protein–protein interaction (PPI) networks. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID). Mice were injected intraperitoneally with ATO (5 mg/kg) for seven days to induce nephrotoxicity, and then the histological morphology of the kidneys, biochemical indices of serum and tissues, and associated protein expressions were observed. The network pharmacology results revealed that the effects of 6G against nephrotoxicity are closely related to apoptosis, and the MAPKs pathway was screened for validation. In animal experiments, 6G improved the histopathological morphology of the kidneys, reduced the levels of renal function markers, enhanced antioxidant activity, and decreased the levels of inflammation. Furthermore, 6G reduced apoptotic cells in kidney tissues, decreased the levels of Bax and c-Caspase-3, and increased the level of Bcl-2. The results of immunohistochemistry and western blotting revealed that 6G significantly inhibited the expressions of p-p38, p-ERK, and p-JNK. The results comprehensively demonstrate the protective effects of 6G against ATO-induced nephrotoxicity. The effects are related to anti-oxidant, anti-inflammatory, and anti-apoptotic properties, possibly through inhibition of the MAPKs pathway. [ABSTRACT FROM AUTHOR]

[Display omitted] • HDACs inhibitors with novel Cap groups were designed and synthesized. • Compounds 9m , 9q , and 12c exhibited promising antiproliferative activities against A375, A549, and MCF-7. • Representative compounds 9m , 9q , and 12c exhibited potent enzyme inhibition activity against HDAC6 (IC 50 : 4.88 ∼ 16.81 nM). • Compound 9q exhibited selective inhibitory activities between HDAC1 and HDAC6 (selectivity factor for HDAC6 over HDAC1 ≈ 41). • The action mechanism underlying the selective inhibitory activities of compound 9q was illustrated via computational approaches. The abnormal biological functions of HDAC6 were closely related to the occurrence and development of various tumors, making HDAC6 gradually become promising therapeutic target for cancer treatment and inspiring researchers to explore and develop selective HDAC inhibitors. In this study, based on the classical pharmacophore model of HDAC inhibitors, 20 compounds were designed and synthesized by modifying the Cap group, and the biological activities of the target compounds were assessed through anti-proliferation and enzyme inhibition experiments. The title compounds exhibited varying degrees of inhibitory activities against the selected tumor cell lines, especially the compounds 9m , 9q , and 12c , which were further evaluated at the enzymatic level. The enzyme inhibition assay showed that compound 12c exerted broad-spectrum enzyme inhibitory activities and compounds 9m and 9q were more inclined to inhibit HDAC6, exhibiting certain selective inhibitory activities among the representative subtypes. Moreover, the binding modes of compounds 9q and 12c in HDAC1&6 were further explored via computational approaches to elucidate the molecular mechanisms underlying selective inhibitory activities, providing valuable hints for the discovery of novel HDAC6 inhibitors. [ABSTRACT FROM AUTHOR]

10-Gingerol (10-Gin), an active ingredient extracted from ginger, has been reported to have beneficial effects on the cardiovascular system. However, its protective effects on myocardial ischemia (MI) and the underlying cellular mechanisms are still unclear. To investigate the protection conferred by 10-Gin against MI injury and its potential mechanisms in cardiomyocytes via patch-clamp and molecular biology techniques. A rat MI model was established using the subcutaneous injection of isoproterenol (85 mg/kg) administered on two consecutive days. 10-Gin was pre-administered to rats for seven days to assess its cardio-protection. The patch-clamp and IonOptix Myocam detection techniques were used to investigated 10-Gin's effects on L -type Ca2+ channels (LTCCs), Ca2+ transients and cell contractility in isolated rat cardiomyocytes. 10-Gin administration alleviated MI injury, improved cardiac function and myocardial histopathology, reduced myocardial infarct area, downregulated oxidative stress and Ca2+ levels, and decreased the expression of apoptotic factors. Importantly, 10-Gin led to an increase in phosphorylated Janus kinase 2 and signal transducer and activator of transcription 3 (JAK2 and STAT3, respectively) expressions. Furthermore, 10-Gin inhibited LTCCs in a concentration-dependent manner with a half-maximal inhibitory concentration of 75.96 μM. Moreover, 10-Gin administration inhibited Ca2+ transients and cell contractility. Our results suggest that 10-Gin exerts cardioprotective effects on MI in vivo and in vitro in connection with the inhibition of oxidative stress and apoptosis via activation of the JAK2/STAT3 signalling pathway, and regulation of Ca2+ homeostasis by LTCCs. [Display omitted] • 10-Gin has a protective effect against ISO-induced myocardial ischemia. • 10-Gin attenuates oxidative stress and apoptosis in ischemic myocardium. • 10-Gin activates the JAK2/STAT3 pathway in ischemic myocardium. • 10-Gin inhibits L -type calcium channels and contraction of cardiomyocytes. [ABSTRACT FROM AUTHOR]

Background: Chloroprocaine is a local ester anesthetic, producing excellent sensory block in clinical use. The Kv7/M potassium channel plays an important role in the control of neuronal excitability. In this study, we investigated the effects of the local anesthetic chloroprocaine on Kv7/M channels as well as the effect of retigabine on chloroprocaine-induced seizures. Methods: A perforated whole-cell patch technique was used to record Kv7 currents from HEK293 cells and M-type currents from rat dorsal root ganglion (DRG) neurons. Results: Chloroprocaine produced a number of effects on Kv7.2/Kv7.3 currents, including a lowering of current amplitudes, a rightward shift in the voltage-dependent activation curves, and a slowing of channel activation. Chloroprocaine had a more selective inhibitory effect on the homomeric Kv7.3 and heteromeric Kv7.2/Kv7.3 channels than on the homomeric Kv7.2 channel. Chloroprocaine also inhibited native M channel currents and induced a depolarization of the DRG neuron membrane potential. Conclusion: Taken together, the findings indicate that chloroprocaine concentration dependently inhibited Kv7/M channel currents. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: Voltage-gated Kv7/KCNQ/M-potassium channels play a pivotal role in controlling neuronal excitability. Genetic reduction of KCNQ channel activity as a result of mutations causes various human diseases such as epilepsy and arrhythmia. Therefore, discovery of small molecules that activate KCNQ channels is an important strategy for clinical intervention of membrane excitability related disorders. In this study, a series of pyrazolo[1,5-a]pyrimidin-7(4H)-ones (PPOs) have been found to be novel activators (openers) of KCNQ2/3 potassium channels through high-throughput screening by using atomic absorption rubidium efflux assay. Based on structure–activity relationship (SAR), the substituted PPOs have been optimized. The 5-(2,6-dichloro-5-fluoropyridin-3-yl)-3-phenyl-2-(trifluoromethyl) pyrazolo[1,5-a]pyrimidin-7(4H)-one (17) was identified as a novel, potent, and selective KCNQ2/3 potassium channel opener by patch-clamp recording assay. [Copyright &y& Elsevier]

Abstract: In the present study, the effects of antihistamines on inwardly rectifying potassium (Kir) channels expressed in Xenopus oocyte were investigated using two-electrode voltage clamp technique. Firstly, effects of antihistamines on two members of Kir2.0 sub-family, Kir2.1 and Kir2.3 were compared. For antihistamines that selectively block histamine H1 receptor, the first-generation antihistamines mepyramine and diphenhydramine inhibited Kir2.3 current by 25.0±2.9% and 17.3±0.7% at concentrations of 100 μM, respectively. In contrast, the second- and third-generation antihistamines astemizole and desloratadine were completely devoid of any inhibitory effect on Kir2.3 current. Histamine H2 receptor antagonist cimetidine, at 100 μM, failed to inhibit Kir2.3 current. On the other hand, Kir2.1 current was not sensitive to any of these drugs. The mepyramine-induced inhibition of Kir2.3 current was significantly reduced by a single point mutation in Kir2.3 (Kir2.3(I213L)), which enhances Kir2.3-PIP2 interaction. Secondly, the effect of mepyramine was also tested on Kir3.4⁎, another member of Kir family. 100 μM mepyramine produced a 30.3±4.6% inhibition on Kir3.4⁎ current. These results suggest that the first-generation histamine H1 receptor antagonists selectively inhibit Kir currents. The inhibitory effect of antihistamines on Kir currents may be involved in their neuronal and cardiac toxic effects caused by drug overdosing. [Copyright &y& Elsevier]

Although farrerol, a characteristically bioactive constituent of Rhododendron dauricum L., exhibits extensive biological and pharmacological activities (e.g., anti-oxidant, anti-immunogenic, and anti-angiogenic) as well as a high drug development potential, its metabolism remains underexplored. Herein, we employed ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry coupled with multiple data post-processing techniques to rapidly identify farrerol metabolites produced in vivo (in rat blood, bile, urine and feces) and in vitro (in rat liver microsomes). As a result, 42 in vivo metabolites and 15 in vitro metabolites were detected, and farrerol shown to mainly undergo oxidation, reduction, (de)methylation, glucose conjugation, glucuronide conjugation, sulfate conjugation, N-acetylation and N-acetylcysteine conjugation. Thus, this work elaborates the metabolic pathways of farrerol and reveals the potential pharmacodynamics forms of farrerol. [ABSTRACT FROM AUTHOR]