Subtype-selective mechanisms of negative allosteric modulators binding to group I metabotropic glutamate receptors.

Group I metabotropic glutamate receptors (mGlu1 and mGlu5) are promising targets for multiple psychiatric and neurodegenerative disorders. Understanding the subtype selectivity of mGlu1 and mGlu5 allosteric sites is essential for the rational design of novel modulators with single- or dual-target mechanism of action. In this study, starting from the deposited mGlu1 and mGlu5 crystal structures, we utilized computational modeling approaches integrating docking, molecular dynamics simulation, and efficient post-trajectory analysis to reveal the subtype-selective mechanism of mGlu1 and mGlu5 to 10 diverse drug scaffolds representing known negative allosteric modulators (NAMs) in the literature. The results of modeling identified six pairs of non-conserved residues and four pairs of conserved ones as critical features to distinguish the selective NAMs binding to the corresponding receptors. In addition, nine pairs of residues are beneficial to the development of novel dual-target NAMs of group I metabotropic glutamate receptors. Furthermore, the binding modes of a reported dual-target NAM (VU0467558) in mGlu1 and mGlu5 were predicted to verify the identified residues that play key roles in the receptor selectivity and the dual-target binding. The results of this study can guide rational structure-based design of novel NAMs, and the approach can be generally applicable to characterize the features of selectivity for other G-protein-coupled receptors.

A clinical study on the efficacy of Yiqi Huayu Jiedu decoction for reducing the risk of postoperative recurrence and metastasis of gastric cancer: Protocol for a multicenter, randomized, double-blind, placebo-controlled trial.

BACKGROUND: Gastric cancer (GC) is one of the top 10 malignant tumors worldwide and poses a great threat to human life and health, the prevention and treatment of which has become the focus and difficulty of medical research. With its unique advantages, traditional Chinese medicine (TCM) is widely used in the prevention and treatment of postoperative recurrence and metastasis of GC as well as the improvement of patients' quality of life. The aim of this study is to elucidate the curative effect and the underlying mechanism of Yiqi Huayu Jiedu (YQHYJD) decoction. METHODS/DESIGN: This is a prospective, multicenter, randomized controlled trial continuing 3 years. Two hundred ninety-eight eligible patients will be randomly divided into 2 groups, the chemotherapy combined with placebo and the chemotherapy combined with YQHYJD group at a ratio of 1:1. All patients will receive the treatment for 6 months and follow up for 3 years. The primary outcomes are disease-free survival, and 1-year, 2-year, 3-year progression-free survival rate, while the secondary outcomes are tumor makers, TCM syndrome score, quality of life score, overall chemotherapy completion rate, intestinal flora diversity test, immune function (T, B lymphocyte subsets and NK cells) test. The Security index includes blood, urine and stool routine, electrocardiogram, liver function (ALT), and renal function (BUN, Scr). All of these outcomes will be analyzed at the end of the trial. DISCUSSION: This research will provide the valuable evidence for the efficacy and safety of Yiqi Huayu Jiedu decoction in postoperative GC. Furthermore, it will be helpful to form a higher level of evidence-based medical basis for TCM in the treatment of GC recurrence and metastasis. TRIAL REGISTRATION: ChiCTR2000039038.

Clinical trials, progression-speed differentiating features and swiftness rule of the innovative targets of first-in-class drugs.

Drugs produce their therapeutic effects by modulating specific targets, and there are 89 innovative targets of first-in-class drugs approved in 2004-17, each with information about drug clinical trial dated back to 1984. Analysis of the clinical trial timelines of these targets may reveal the trial-speed differentiating features for facilitating target assessment. Here we present a comprehensive analysis of all these 89 targets, following the earlier studies for prospective prediction of clinical success of the targets of clinical trial drugs. Our analysis confirmed the literature-reported common druggability characteristics for clinical success of these innovative targets, exposed trial-speed differentiating features associated to the on-target and off-target collateral effects in humans and further revealed a simple rule for identifying the speedy human targets through clinical trials (from the earliest phase I to the 1st drug approval within 8 years). This simple rule correctly identified 75.0% of the 28 speedy human targets and only unexpectedly misclassified 13.2% of 53 non-speedy human targets. Certain extraordinary circumstances were also discovered to likely contribute to the misclassification of some human targets by this simple rule. Investigation and knowledge of trial-speed differentiating features enable prioritized drug discovery and development.

Neferine induces autophagy-dependent cell death in apoptosis-resistant cancers via ryanodine receptor and Ca2+-dependent mechanism.

Resistance of cancer cells to chemotherapy is a significant clinical concern and mechanisms regulating cell death in cancer therapy, including apoptosis, autophagy or necrosis, have been extensively investigated over the last decade. Accordingly, the identification of medicinal compounds against chemoresistant cancer cells via new mechanism of action is highly desired. Autophagy is important in inducing cell death or survival in cancer therapy. Recently, novel autophagy activators isolated from natural products were shown to induce autophagic cell death in apoptosis-resistant cancer cells in a calcium-dependent manner. Therefore, enhancement of autophagy may serve as additional therapeutic strategy against these resistant cancers. By computational docking analysis, biochemical assays, and advanced live-cell imaging, we identified that neferine, a natural alkaloid from Nelumbo nucifera, induces autophagy by activating the ryanodine receptor and calcium release. With well-known apoptotic agents, such as staurosporine, taxol, doxorubicin, cisplatin and etoposide, utilized as controls, neferine was shown to induce autophagic cell death in a panel of cancer cells, including apoptosis-defective and -resistant cancer cells or isogenic cancer cells, via calcium mobilization through the activation of ryanodine receptor and Ulk-1-PERK and AMPK-mTOR signaling cascades. Taken together, this study provides insights into the cytotoxic mechanism of neferine-induced autophagy through ryanodine receptor activation in resistant cancers.

Identification of the gene signature reflecting schizophrenia's etiology by constructing artificial intelligence-based method of enhanced reproducibility.

AIMS: As one of the most fundamental questions in modern science, "what causes schizophrenia (SZ)" remains a profound mystery due to the absence of objective gene markers. The reproducibility of the gene signatures identified by independent studies is found to be extremely low due to the incapability of available feature selection methods and the lack of measurement on validating signatures' robustness. These irreproducible results have significantly limited our understanding of the etiology of SZ. METHODS: In this study, a new feature selection strategy was developed, and a comprehensive analysis was then conducted to ensure a reliable signature discovery. Particularly, the new strategy (a) combined multiple randomized sampling with consensus scoring and (b) assessed gene ranking consistency among different datasets, and a comprehensive analysis among nine independent studies was conducted. RESULTS: Based on a first-ever evaluation of methods' reproducibility that was cross-validated by nine independent studies, the newly developed strategy was found to be superior to the traditional ones. As a result, 33 genes were consistently identified from multiple datasets by the new strategy as differentially expressed, which might facilitate our understanding of the mechanism underlying the etiology of SZ. CONCLUSION: A new strategy capable of enhancing the reproducibility of feature selection in current SZ research was successfully constructed and validated. A group of candidate genes identified in this study should be considered as great potential for revealing the etiology of SZ.

How Does Chirality Determine the Selective Inhibition of Histone Deacetylase 6? A Lesson from Trichostatin A Enantiomers Based on Molecular Dynamics.

Histone deacetylase 6 (HDAC6) plays a key role in a variety of neurological disorders, which makes it attractive drug target for the treatment of Alzheimer's disease, Parkinson's disease, and memory/learning impairment. The selectivity of HDAC6 inhibitors (sHDAC6Is) are widely considered to be susceptible to the sizes of their Cap group and the physicochemical properties of their linker or zinc-binding group, which makes the discovery of new sHDAC6Is extremely difficult. With the discovery of the distinct selectivity between Trichostatin A (TSA) enantiomers, the chirality residing in the connective units between TSA's Cap and linker shows a great impact on its selectivity. However, the mechanism underlining ( S)-TSA's selectivity is still elusive, and the way chirality switches the selective ( S)-TSA to nonselective ( R)-TSA is unknown. In this study, multiple computational approaches were collectively applied to explore, validate, and differentiate the binding modes of two TSA enantiomers in HDACs (especially the HDAC6) at atomic level. First, two nonconservative residues (G200/M205 and Y197/F202 in HDAC1/6) in loop3 and four conservative residues deep inside the hydrophobic binding pocket were discovered as the decisive residues of ( S)-TSA's selectivity toward HDAC6. Then, a novel mechanism underlying the selectivity of ( S)-TSA toward HDAC6 was proposed, which was composed of the trigger by two nonconservative residues F202 and M205 in HDAC6 and a subsequently improved fit of ( S)-TSA deep inside HDAC6's hydrophobic binding pocket. TSA enantiomers were used as a molecular probe to explore the mechanism underlying sHDAC6Is' selectivity in this study. Because of their decisive roles in ( S)-TSA's selectivity to HDAC6, both F202 and M205 in HDAC6 should be especially considered in the discovery of novel sHDAC6Is.

Vascular endothelial growth factor activates neural stem cells through epidermal growth factor receptor signal after spinal cord injury.

AIMS: Neural stem cells (NSCs) in the adult mammalian spinal cord are activated in response to spinal cord injury (SCI); however, mechanisms modulating this process are not clear. Here, we noticed SCI elevated expression of vascular endothelial growth factor (VEGF) and we aimed to validate the roles of VEGF in NSCs activation after SCI and investigated the related signals during the process. METHODS: In vitro we detected whether VEGF promoted spinal cord NSCs proliferation and investigated the involved signals; In vivo, we injected VEGF into rat spinal cord to check the NSCs activation. RESULTS: In vitro, VEGF triggered spinal cord NSCs proliferation and maintained self-renewal. Further investigations demonstrated VEGF transactivated epidermal growth factor receptor (EGFR) through VEGF receptor 2 (VEGFR2) to promote spinal cord NSCs proliferation. In vivo, we injected VEGF into spinal cord by laminectomy to confirm the roles of VEGF-VEGFR2-EGFR signals in NSCs activation. VEGF significantly elevated the number of activated NSCs and increased EGFR phosphorylation. In contrast, intraspinal injection of specific inhibitors targeting EGFR and VEGFR2 decreased NSCs activation after SCI. Our results demonstrate that VEGF-VEGFR2-EGFR axis is important for NSCs activation after SCI, providing new insights into the mechanisms of spinal cord NSCs activation postinjury.

Identification of novel immune-relevant drug target genes for Alzheimer's Disease by combining ontology inference with network analysis.

AIMS: Alzheimer's disease (AD) is one of the leading causes of death in elderly people. Its pathogenesis is greatly associated with the abnormality of immune system. However, only a few immune-relevant AD drug target genes have been discovered up to now, and it is speculated that there are still many potential drug target genes of AD (at least immune-relevant genes) to be discovered. Thus, this study was designed to identify novel AD drug target genes and explore their biological properties. METHODS: A combinatorial approach was adopted for the first time to discover AD drug targets by collectively considering ontology inference and network analysis. Moreover, a novel strategy limiting the distance of reasoning and in turn reducing noise interference was further proposed to improve inference performance. Potential AD drug target genes were discovered by integrating information of multiple popular databases (TTD, DrugBank, PharmGKB, AlzGene, and BioGRID). Then, the enrichment analyses of the identified drug targets genes based on nine well-known pathway-related databases were conducted to explore the function of the identified potential drug target genes. RESULTS: Eighteen potential drug target genes were finally identified, and 13 of them had been reported to be closely associated with AD. Enrichment analyses of these identified drug target genes, based on nine pathway-related databases, revealed that the enriched terms were primarily focus on immune-relevant biological processes. Four of those identified drug target genes are involved in the classical complement pathway and process of antigen presenting. CONCLUSION: The well-reproducible results showed the good performance of the combinatorial approach, and the remaining five new targets could be a good starting point for our understanding of the pathogenesis and drug discovery of AD. Moreover, this study supported validity of the combinatorial approach integrating ontology inference with network analysis in the discovery of novel drug target for neurological diseases.

Assessing the Performances of Protein Function Prediction Algorithms from the Perspectives of Identification Accuracy and False Discovery Rate.

The function of a protein is of great interest in the cutting-edge research of biological mechanisms, disease development and drug/target discovery. Besides experimental explorations, a variety of computational methods have been designed to predict protein function. Among these in silico methods, the prediction of BLAST is based on protein sequence similarity, while that of machine learning is also based on the sequence, but without the consideration of their similarity. This unique characteristic of machine learning makes it a good complement to BLAST and many other approaches in predicting the function of remotely relevant proteins and the homologous proteins of distinct function. However, the identification accuracies of these in silico methods and their false discovery rate have not yet been assessed so far, which greatly limits the usage of these algorithms. Herein, a comprehensive comparison of the performances among four popular prediction algorithms (BLAST, SVM, PNN and KNN) was conducted. In particular, the performance of these methods was systematically assessed by four standard statistical indexes based on the independent test datasets of 93 functional protein families defined by UniProtKB keywords. Moreover, the false discovery rates of these algorithms were evaluated by scanning the genomes of four representative model organisms (Homo sapiens, Arabidopsis thaliana, Saccharomyces cerevisiae and Mycobacterium tuberculosis). As a result, the substantially higher sensitivity of SVM and BLAST was observed compared with that of PNN and KNN. However, the machine learning algorithms (PNN, KNN and SVM) were found capable of substantially reducing the false discovery rate (SVM < PNN < KNN). In sum, this study comprehensively assessed the performance of four popular algorithms applied to protein function prediction, which could facilitate the selection of the most appropriate method in the related biomedical research.

N-Desmethyldauricine Induces Autophagic Cell Death in Apoptosis-Defective Cells via Ca2+ Mobilization.

Resistance of cancer cells to chemotherapy remains a significant problem in oncology. Mechanisms regulating programmed cell death, including apoptosis, autophagy or necrosis, in the treatment of cancers have been extensively investigated over the last few decades. Autophagy is now emerging as an important pathway in regulating cell death or survival in cancer therapy. Recent studies demonstrated variety of natural small-molecules could induce autophagic cell death in apoptosis-resistant cancer cells, therefore, discovery of novel autophagic enhancers from natural products could be a promising strategy for treatment of chemotherapy-resistant cancer. By computational virtual docking analysis, biochemical assays, and advanced live-cell imaging techniques, we have identified N-desmethyldauricine (LP-4), isolated from rhizoma of Menispermum dauricum DC as a novel inducer of autophagy. LP-4 was shown to induce autophagy via the Ulk-1-PERK and Ca2+/Calmodulin-dependent protein kinase kinase ß (CaMKKß)-AMPK-mTOR signaling cascades, via mobilizing calcium release through inhibition of SERCA, and importantly, lead to autophagic cell death in a panel of cancer cells, apoptosis-defective and apoptosis-resistant cells. Taken together, this study provides detailed insights into the cytotoxic mechanism of a novel autophagic compound that targeting the apoptosis resistant cancer cells, and new implication on drug discovery from natural products for drug resistant cancer therapy.

Comprehensive profiling and characterization of chemical constituents of rhizome of Anemarrhena asphodeloides Bge.

The rhizome of Anemarrhena asphodeloides Bge. is commonly used as an herbal medicine in China. In this study, ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) was used, in both negative and positive ion modes, to comprehensively analyze the chemical constituents of A. asphodeloides. From the intact precursor ions, MS/MS fragmentation information, and previous reports, we identified 89 compounds. These compounds included 8 cyclic peptides, 11 flavones (9 xanthones), 45 steroidal saponins, 15 fatty acids, 3 lignans, and 7 other compounds. Dimer xanthones and cyclic peptides are reported for the first time in A. asphodeloides. The analytical method we have developed is simple, reliable, and effective. The results provide comprehensive information on the metabolite profile of A. asphodeloides, which may benefit the quality control and further utilization of A. asphodeloides.

The Human Kinome Targeted by FDA Approved Multi-Target Drugs and Combination Products: A Comparative Study from the Drug-Target Interaction Network Perspective.

The human kinome is one of the most productive classes of drug target, and there is emerging necessity for treating complex diseases by means of polypharmacology (multi-target drugs and combination products). However, the advantages of the multi-target drugs and the combination products are still under debate. A comparative analysis between FDA approved multi-target drugs and combination products, targeting the human kinome, was conducted by mapping targets onto the phylogenetic tree of the human kinome. The approach of network medicine illustrating the drug-target interactions was applied to identify popular targets of multi-target drugs and combination products. As identified, the multi-target drugs tended to inhibit target pairs in the human kinome, especially the receptor tyrosine kinase family, while the combination products were able to against targets of distant homology relationship. This finding asked for choosing the combination products as a better solution for designing drugs aiming at targets of distant homology relationship. Moreover, sub-networks of drug-target interactions in specific disease were generated, and mechanisms shared by multi-target drugs and combination products were identified. In conclusion, this study performed an analysis between approved multi-target drugs and combination products against the human kinome, which could assist the discovery of next generation polypharmacology.

Cloning and Characterization of ifitm1 and ifitm3 Expression During Early Zebrafish Development - CORRIGENDUM.

The authors apologise for errors in the corresponding authors details given on page 1 of the article. Below is the correct information of the corresponding author and email address : 1) Wei-Wei Xue, Huan-Nan Wang, Zhi-Meng Wang, Meng-Xi Qiu, Jing Che, Feng-Jiao Deng* and Jiang-Dong Liu* 2) *All correspondence to: Feng-Jiao Deng and Jiang-Dong Liu. e-mail: fish4@whu.edu.cn 3) All authors are from the same one laboratory. The second laboratory was superfluous and should be deleted.

Cloning and characterization of ifitm1 and ifitm3 expression during early zebrafish development.

The family of interferon-inducible transmembrane proteins (IFITMs) plays a crucial role in inhibiting proliferation, promoting homotypic cell adhesion and mediating germ cell development. In the present study, the full-length cDNAs of zebrafish ifitm1 (744 bp) and ifitm3 (702 bp) were obtained by rapid amplification of cDNA ends (RACE). Reverse transcription polymerase chain reaction (RT-PCR) analysis showed that ifitm1 mRNA was expressed in the ovary, testis, brain, muscle, liver and kidney, while ifitm3 mRNA was only detected in the ovary. Based on in situ hybridization, ifitm1 mRNA was found to be strongly expressed in the ooplasm from stage I to stage II and ifitm3 mRNA was also strongly expressed in the ooplasm from stage I to stage II, furthermore ifitm3 expression ultimately localized to the cortex region beneath the plasma membrane of stage IV oocytes. During development, ifitm1 expression was initially detected in the enveloping layer cells and deep layer cells of shield stage embryos. Then, throughout the segmentation phase (10.25-24 hours post-fertilization (hpf)), ifitm1 expression was mainly detected in the head, trunk and tail regions. Unlike ifitm1, ifitm3 expression was initially detected in sphere stage embryos and was then broadly expressed throughout the embryo from the 70% epiboly stage to 24 hpf. Interestingly, ifitm3 was also expressed in primordial germ cells (PGCs) from the bud stage to 24 hpf. This expression analysis indicates that zebrafish ifitm1 may play a critical role in early organogenesis and may perform immune or hematopoietic functions and ifitm3 might be necessary for PGC migration and the formation of female germ cells.

(Z)3,4,5,4'-trans-tetramethoxystilbene, a new analogue of resveratrol, inhibits gefitinb-resistant non-small cell lung cancer via selectively elevating intracellular calcium level.

Calcium is a second messenger which is required for regulation of many cellular processes. However, excessive elevation or prolonged activation of calcium signaling would lead to cell death. As such, selectively regulating calcium signaling could be an alternative approach for anti-cancer therapy. Recently, we have identified an effective analogue of resveratrol, (Z)3,4,5,4'-trans-tetramethoxystilbene (TMS) which selectively elevated the intracellular calcium level in gefitinib-resistant (G-R) non-small-cell lung cancer (NSCLC) cells. TMS exhibited significant inhibitory effect on G-R NSCLC cells, but not other NSCLC cells and normal lung epithelial cells. The phosphorylation and activation of EGFR were inhibited by TMS in G-R cells. TMS induced caspase-independent apoptosis and autophagy by directly binding to SERCA and causing endoplasmic reticulum (ER) stress and AMPK activation. Proteomics analysis also further confirmed that mTOR pathway, which is the downstream of AMPK, was significantly suppressed by TMS. JNK, the cross-linker of ER stress and mTOR pathway was significantly activated by TMS. In addition, the inhibition of JNK activation can partially block the effect of TMS. Taken together, TMS showed promising anti-cancer activity by mediating calcium signaling pathway and inducing apoptosis as well as autophagy in G-R NSCLC cells, providing strategy in designing multi-targeting drug for treating G-R patients.

1,6-Bis(p-tol-yloxy)hexa-ne.

The title compound, C20H26O2, crystallized with one half-mol-ecule in the asymmetric unit. The whole mol-ecule is generated by inversion symmetry, with the center of inversion being situated at the mid-point of the central -CH2-CH2- bond of the bridging hexane chain. In the crystal, mol-ecules stack in columns along the b axis. C-H⋯π inter-actions are present within the columns.

Isolation, characterization and acetylcholinesterase inhibitory activity of alkaloids from roots of Stemona sessilifolia.

Two new alkaloids, named stenine A (1) and stenine B (2), along with the known compounds neostenine (3), stenine (4) and neotuberostemonine (5), were isolated from the roots of Stemona sessilifolia. Their structures were elucidated by 1D- and 2D-NMR spectra and X-ray single-crystal diffraction experiment. Anti-acetylcholinesterase (AChE) activity of compounds 1-5 were also tested. Compounds 2 and 4 showed significant anti-acetylcholinesterase activities, with IC50 values of 2.1±0.2 µM and 19.8±2.5 µM, resp. The mode of AChE inhibition by Compound 2 (the most potential AChE inhibitor) was reversible and competitive. In addition, molecular modeling was performed to explore the binding mode of compound 2 with AChE.

Steroidal alkaloids from Holarrhena antidysenterica as acetylcholinesterase inhibitors and the investigation for structure-activity relationships.

AIMS: Inhibition of acetylcholinesterase (AChE) is still considered as a strategy for the treatment of neurological disorders such as Alzheimer's disease (AD). Many plant derived alkaloids (such as huperzine A, galanthamine and rivastigmine) are known for their AChE inhibitory activity. The aim of the present work was to isolate and identify new AChE inhibitors from Holarrhen antidysenterica. MAIN METHODS: These compounds were tested for AChE inhibiting activity by the Ellman's method in 96-well microplates. In addition, molecular modeling was performed to explore the binding mode of inhibitors 1-5 at the active site of AChE, and the preliminary structure-activity relationships (SARs) were discussed. KEY FINDINGS: In the course of searching for AChE inhibitors from herb medicines, the total alkaloidal extract from the seeds of H. antidysenterica was found having potent AChE inhibitory activity with an IC(50) value of 6.1 µg/mL. Further bioactivity-guided chromatographic fractionation afforded five steroidal alkaloids, conessine 1, isoconessimine 2, conessimin 3, conarrhimin 4 and conimin 5. All the isolated compounds, except for 2, showed strong AChE inhibiting activity with IC(50) values ranging from 4 to 28 µM. The most active inhibitor is compound 3 with an IC(50) value of 4 µM. The mode of AChE inhibition by 3 was reversible and non-competitive. SIGNIFICANCE: The results suggest that these alkaloids could be potential candidates for further development of new drugs against AD.

[Photostimulated luminescence properties of KCl:Cu+ after UV excitation].

KCl:Cu+ powder sample was prepared with high temperature solid reaction process. After being excited by UV, the sample shows near ultraviolet blue luminescence by stimulation with 560 nm light. The research result indicates that Cu+ acts as a luminous center, and Cu+ does not change into Cu2+ by UV irradiation. So, Cu+ ions do not act as hole traps, while anion vacancies act as electron traps. Once UV excited sample is stimulated, electrons from F center combine with hole trapping center or VK center, and cause subsequent energy transfer to Cu+ ion. Then, a character emission attributed to d-s transition of Cu+ in lattice occurs.