Excavations in drug chirality: 1. Cyclothiazide

There is a great deal of current interest in the role and importance of chirality in the development of new drugs, but little attention is being paid to the stereochemistry of older drugs. Indeed, many older chiral drugs were introduced without adequate information on their stereochemical identity or composition. We have examined one such drug, the antihypertensive diuretic agent cyclothiazide. Standard sources of drug information and the research literature do not provide data on the stereochemical composition of clinically used cyclothiazide, although scattered reports indicate that the drug may consist of "several stereoisomers." Inspection of the chemical structure of the drug, 6-chloro-3,4-dihydro-3-(5-norbornen-2-yl)-2H-1,2,4-benzothiadiazin e-7- sulfonamide 1,1-dioxide, shows that it can exist as eight stereoisomers that may form four racemates. Using synthesis, fast-atom-bombardment mass spectrometry, gas-liquid chromatography, chiral and nonchiral high-performance liquid chromatography, and nuclear magnetic resonance spectroscopy, we determined that pharmaceutical cyclothiazide is in fact a mixture of the eight stereoisomers in the form of the four racemates. The two racemates with endo configuration at the norbornene moiety predominate over the exo racemates, and small but significant differences in isomer distribution between different batches of the drug were observed. We urge that in studies of older drugs the stereochemical details be considered.     

Discovery and SAR analysis of 5-chloro-4-((substituted phenyl)amino)pyrimidine bearing histone deacetylase inhibitors

Histone deacetylases (HDACs) are validated targets for the development of anticancer drugs in epigenetics. In the discovery of novel HDAC inhibitors with anticancer potency, the 5-chloro-4-((substituted phenyl)amino)pyrimidine fragment is assembled as a cap group into the structure of HDAC inhibitors. The SAR revealed that presence of small groups (such as methoxy substitution) is beneficial for the HDAC inhibitory activity. In the enzyme inhibitory selectivity test, compound L20 exhibited class I selectivity with IC₅₀ values of 0.684 µM (selectivity index of >1462), 2.548 µM (selectivity index of >392), and 0.217 µM (selectivity index of >4608) against HDAC1, HDAC2 and HDAC3 compared with potency against HDAC6 (IC₅₀ value of >1000 µM), respectively. In the antiproliferative assay, compound L20 showed both hematological and solid cancer inhibitory activities. In the flow cytometry, L20 promoted G0/G1 phase cell cycle arrest and apoptosis of K562 cells.     

Effect of High-Intensity Interval Training on Cardiac Apoptosis Markers in Methamphetamine-Dependent Rats

Chronic methamphetamine use increases apoptosis, leading to heart failure and sudden cardiac death. Previous studies have shown the importance of high-intensity interval training (HIIT) in reducing indices of cardiac tissue apoptosis in different patients, but in the field of sports science, the molecular mechanisms of apoptosis in methamphetamine-dependent rats are still unclear. The present article aimed to investigate the changes in cardiac apoptosis markers in methamphetamine-dependent rats in response to HIIT. Left ventricular tissue was used to evaluate caspase-3, melusin, FAK, and IQGAP1 gene expression. Rats were divided into four groups: sham, methamphetamine (METH), METH-control, and METH-HIIT. METH was injected for 21 days and then the METH-HIIT group performed HIIT for 8 weeks at 5 sessions per week. The METH groups showed increased caspase-3 gene expression and decreased melusin, FAK, and IQGAP1 when compared to the sham group. METH-HIIT showed decreased caspase-3 and increased melusin and FAK gene expression compared with the METH and METH-control groups. The IQGAP1 gene was higher in METH-HIIT when compared with METH, while no difference was observed between METH-HIIT and METH-control. Twenty-one days of METH exposure increased apoptosis markers in rat cardiac tissue; however, HIIT might have a protective effect, as shown by the apoptosis markers.     

抑郁症易感基因和抗抑郁药物靶点相关[]神经细胞类型及相互作用网络分析

基于抑郁症的全基因组关联分析研究(GWAS),对于获得的单核苷酸多态性位点(SNP)使用Haploreg软件进行基因注释,得到SNP注释的102个易感基因.。使用MAGMA软件对GWAS的汇总统计数据做基因水平的分析,获得了270个校正之后显著的基因,两者合并共得到320个抑郁症易感基因。通过药物数据库Drugbank获取133个抗抑郁药物靶点基因。使用EWCE包对抑郁症易感基因和抗抑郁药物靶点在三套脑组织单细胞测序数据中,分别进行神经细胞类型富集分析。结果发现大脑皮质的GABA神经元(抑制性神经元)和谷氨酸能神经元(兴奋性神经元)是抑郁症易感基因和抗抑郁药物靶点共同的神经元。这两种类型的神经细胞可能是抗抑郁药物与抑郁症易感基因相互作用的神经细胞,另外少突胶质前体细胞可能是抑郁症特有的易感神经细胞。使用Network Calculator软件构建网络并进行进行网络拓扑学参数分析。结果表明抑郁症易感基因与抗抑郁药物靶点组成了一个具有显著的相互连接的网络。本研究从单细胞层面揭示抑郁症的遗传机制,在网络层面为寻找新的抗抑郁药物靶点提供了一定的启示。     

Cell specific expression of three genes involved in plasma membrane sucrose transport in developingVicia faba seed

Summary In developing seeds ofVicia faba, transfer cells line the inner surface of the seed coat and the juxtaposed epidermal surface of the cotyledons. Circumstantial evidence, derived from anatomical and physiological studies, indicates that these cells are the likely sites of sucrose efflux to, and influx from, the seed apoplasm, respectively. In this study, expression of an H⁺/sucrose symporter-gene was found to be localised to the epidermal-transfer cell complexes of the cotyledons. The sucrose binding protein (SBP) gene was expressed in these cells as well as in the thin-walled parenchyma transfer cells of the seed coat. SBP was immunolocalised exclusively to the plasma membranes located in the wall ingrowth regions of the transfer cells. In addition, a plasma membrane H⁺-ATPase was most abundant in the wall ingrowth regions with decreasing levels of expression at increasing distance from the transfer cell layers. The observed co-localisation of high densities of a plasma membrane H⁺-ATPase and sucrose transport proteins to the wall ingrowths of the seed coat and cotyledon transfer cells provides strong evidence that these regions are the principal sites of facilitated membrane transport of sucrose to and from the seed apoplasm.Abbreviations BCIP 5-bromo-4-chloro-3-indolyl phosphate - DIG digoxigenin - H⁺-ATPase plasma membrane H⁺-translocating adenosine triphosphatase - Ig immunoglobulin - LeSUT1 tomato H⁺/sucrose symporter - SBP sucrose binding protein     

Root border cells take up and release glucose-C

BACKGROUND AND AIMS: Border cells are released from the root tips of many plant species, and can remain viable in the rhizosphere for 1 week. Whether border cells are capable of controlled glucose exchange with their environment was investigated. METHODS: Border cells were removed from Zea mays L. root tips, and immersed in (14)C-labelled D-glucose. In one experiment, the hexose transport inhibitor, phlorizin, was used to investigate active glucose uptake from a range of glucose concentrations. In another experiment, glucose efflux from border cells was monitored over time. KEY RESULTS: Glucose uptake by the border cells increased with increasing glucose concentration from 0.2 to 20 mm. At 0.2 mm glucose, uptake was mainly active, as evidenced by the approx. 60 % inhibition with phlorizin. At 2 and 20 mm glucose, however, uptake was mainly via diffusion, as phlorizin inhibition was negligible. Glucose efflux increased with time for live border cells in both 2 and 20 mm glucose. There was no clear efflux/time pattern for heat-killed border cells. CONCLUSIONS: Border cells actively take up glucose, and also release it. Under our experimental conditions, glucose uptake and efflux were of similar order of magnitude. In the rhizosphere net glucose exchange will almost certainly depend on local soil conditions.     

新一代PEG在修饰抗原和药物缓释中的应用

聚乙二醇及其衍生物是具有许多优良性质的高分子化合物,由于良好的生物相容性、无毒、无免疫原性,广泛用于生物医学领域。本文总结聚乙二醇的发展历史和新一代聚乙二醇的特点,阐述聚乙二醇化修饰的目的,特别是在抗原修饰、血型改造和细胞移植等方面的应用,重点对聚乙二醇在药物缓释方面的应用进行了系统的综述。     

Genome‐wide association study identifies loci associated with liability to alcohol and drug dependence that is associated with variability in reward‐related ventral striatum activity in African‐ and European‐Americans

Genetic influences on alcohol and drug dependence partially overlap, however, specific loci underlying this overlap remain unclear. We conducted a genome‐wide association study (GWAS) of a phenotype representing alcohol or illicit drug dependence (ANYDEP) among 7291 European‐Americans (EA; 2927 cases) and 3132 African‐Americans (AA: 1315 cases) participating in the family‐based Collaborative Study on the Genetics of Alcoholism. ANYDEP was heritable (h ² in EA = 0.60, AA = 0.37). The AA GWAS identified three regions with genome‐wide significant (GWS; P < 5E‐08) single nucleotide polymorphisms (SNPs) on chromosomes 3 (rs34066662, rs58801820) and 13 (rs75168521, rs78886294), and an insertion‐deletion on chromosome 5 (chr5:141988181). No polymorphisms reached GWS in the EA. One GWS region (chromosome 1: rs1890881) emerged from a trans‐ancestral meta‐analysis (EA + AA) of ANYDEP, and was attributable to alcohol dependence in both samples. Four genes (AA: CRKL, DZIP3, SBK3; EA: P2RX6) and four sets of genes were significantly enriched within biological pathways for hemostasis and signal transduction. GWS signals did not replicate in two independent samples but there was weak evidence for association between rs1890881 and alcohol intake in the UK Biobank. Among 118 AA and 481 EA individuals from the Duke Neurogenetics Study, rs75168521 and rs1890881 genotypes were associated with variability in reward‐related ventral striatum activation. This study identified novel loci for substance dependence and provides preliminary evidence that these variants are also associated with individual differences in neural reward reactivity. Gene discovery efforts in non‐European samples with distinct patterns of substance use may lead to the identification of novel ancestry‐specific genetic markers of risk.     

Conformational control in structure-based drug design

In structure-based drug design, the basic goal is to design molecules that fit complementarily to a given binding pocket. Since such computationally modeled molecules may not adopt the intended bound conformation outside the binding pocket, one challenge is to ensure that the designed ligands adopt similar low energy conformations both inside and outside of the binding pocket. Computational chemistry methods and conformational preferences of small molecules from PDB and Cambridge Structural Database (CSD) can be used to predict the bound structures of the designed molecules. Herein, we review applications of conformational control in structure-based drug design using selected examples from the recent medicinal chemistry literature. The main purpose is to highlight some intriguing conformational features that can be applied to other drug discovery programs.