排序方式: 共有638条查询结果,搜索用时 15 毫秒
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Franck Potet Amanda N. Lorinc Sebastien Chaigne Corey R. Hopkins Raghav Venkataraman Svetlana Z. Stepanovic L. Michelle Lewis Emily Days Veniamin Y. Sidorov Darren W. Engers Beiyan Zou David Afshartous Alfred L. George Jr. Courtney M. Campbell Jeffrey R. Balser Min Li Franz J. Baudenbacher Craig W. Lindsley C. David Weaver Sabina Kupershmidt 《The Journal of biological chemistry》2012,287(47):39613-39625
The human Ether-à-go-go-related gene (hERG)-encoded K+ current, IKr is essential for cardiac repolarization but is also a source of cardiotoxicity because unintended hERG inhibition by diverse pharmaceuticals can cause arrhythmias and sudden cardiac death. We hypothesized that a small molecule that diminishes IKr block by a known hERG antagonist would constitute a first step toward preventing hERG-related arrhythmias and facilitating drug discovery. Using a high-throughput assay, we screened a library of compounds for agents that increase the IC70 of dofetilide, a well characterized hERG blocker. One compound, VU0405601, with the desired activity was further characterized. In isolated, Langendorff-perfused rabbit hearts, optical mapping revealed that dofetilide-induced arrhythmias were reduced after pretreatment with VU0405601. Patch clamp analysis in stable hERG-HEK cells showed effects on current amplitude, inactivation, and deactivation. VU0405601 increased the IC50 of dofetilide from 38.7 to 76.3 nm. VU0405601 mitigates the effects of hERG blockers from the extracellular aspect primarily by reducing inactivation, whereas most clinically relevant hERG inhibitors act at an inner pore site. Structure-activity relationships surrounding VU0405601 identified a 3-pyridiyl and a naphthyridine ring system as key structural components important for preventing hERG inhibition by multiple inhibitors. These findings indicate that small molecules can be designed to reduce the sensitivity of hERG to inhibitors. 相似文献
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S Dupont G Lemetais T Ferreira P Cayot P Gervais L Beney 《Evolution; international journal of organic evolution》2012,66(9):2961-2968
Sterols, essential lipids of most eukaryotic cells, ensure important structural and signaling functions. The selection pressure that has led to different dominant sterols in the three eukaryotic kingdoms remains unknown. Here, we investigated the influence of the progression in the different steps of the ergosterol biosynthetic pathway (EBP) on the yeast resistance to transitions from aqueous to aerial media, typical perturbations of the higher fungi habitats. Five mutants of the EBP (ergΔ), accumulating different sterol intermediates in the EBP, and the wild‐type (WT) strain were exposed to drying under atmospheric air or nitrogen and wetting. Results show that the progression in the EBP parallels an increase in the yeast resistance to air‐drying with a maximal survival rate for the WT strain. When drying/wetting was performed under nitrogen, yeast survival was higher, particularly for the earlier mutants of the EBP. Thus, ergosterol, through its protective role against mechanical and oxidative stress, might have been selected by the pressure induced by drying/wetting cycles occurring in the fungi habitats. These results support the Bloch hypothesis, which postulates that the properties of sterols are gradually optimized for function along the biosynthetic pathway and provide a response to the enduring question “why ergosterol in fungi?”. 相似文献
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The Exosome Secretory Pathway Transports Amyloid Precursor Protein Carboxyl-terminal Fragments from the Cell into the Brain Extracellular Space 总被引:1,自引:0,他引:1
Rocio Perez-Gonzalez Sebastien A. Gauthier Asok Kumar Efrat Levy 《The Journal of biological chemistry》2012,287(51):43108-43115
In vitro studies have shown that neuronal cell cultures secrete exosomes containing amyloid-β precursor protein (APP) and the APP-processing products, C-terminal fragments (CTFs) and amyloid-β (Aβ). We investigated the secretion of full-length APP (flAPP) and APP CTFs via the exosome secretory pathway in vivo. To this end, we developed a novel protocol designed to isolate exosomes secreted into mouse brain extracellular space. Exosomes with typical morphology were isolated from freshly removed mouse brains and from frozen mouse and human brain tissues, demonstrating that exosomes can be isolated from post-mortem tissue frozen for long periods of time. flAPP, APP CTFs, and enzymes that cleave both flAPP and APP CTFs were identified in brain exosomes. Although higher levels of both flAPP and APP CTFs were observed in exosomes isolated from the brains of transgenic mice overexpressing human APP (Tg2576) compared with wild-type control mice, there was no difference in the number of secreted brain exosomes. These data indicate that the levels of flAPP and APP CTFs associated with exosomes mirror the cellular levels of flAPP and APP CTFs. Interestingly, exosomes isolated from the brains of both Tg2576 and wild-type mice are enriched with APP CTFs relative to flAPP. Thus, we hypothesize that the exosome secretory pathway plays a pleiotropic role in the brain: exosome secretion is beneficial to the cell, acting as a specific releasing system of neurotoxic APP CTFs and Aβ, but the secretion of exosomes enriched with APP CTFs, neurotoxic proteins that are also a source of secreted Aβ, is harmful to the brain. 相似文献
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J Liddle P Bamborough MD Barker S Campos CW Chung RP Cousins P Faulder ML Heathcote H Hobbs DS Holmes C Ioannou C Ramirez-Molina MA Morse R Osborn JJ Payne JM Pritchard WL Rumsey DT Tape G Vicentini C Whitworth RA Williamson 《Bioorganic & medicinal chemistry letters》2012,22(16):5222-5226
The lead optimization of a series of potent azaindole IKK2 inhibitors is described. Optimization of the human whole blood activity and selectivity over IKK1 in parallel led to the discovery of 16, a potent and selective IKK2 inhibitor showing good efficacy in a rat model of neutrophil activation. 相似文献
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McCarthy AR Pirrie L Hollick JJ Ronseaux S Campbell J Higgins M Staples OD Tran F Slawin AM Lain S Westwood NJ 《Bioorganic & medicinal chemistry》2012,20(5):1779-1793
The tenovins are small molecule inhibitors of the NAD(+)-dependent family of protein deacetylases known as the sirtuins. There remains considerable interest in inhibitors of this enzyme family due to possible applications in both cancer and neurodegenerative disease therapy. Through the synthesis of novel tenovin analogues, further insights into the structural requirements for activity against the sirtuins in vitro are provided. In addition, the activity of one of the analogues in cells led to an improved understanding of the function of SirT1 in cells. 相似文献
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Malysheva YB Combes S Allegro D Peyrot V Knochel P Gavryushin AE Fedorov AY 《Bioorganic & medicinal chemistry》2012,20(14):4271-4278
A series of novel antimitotic hybrids were synthesized in good yields by linking of azide-containing colchicine congeners with acetylene-substituted tubulizine-type derivatives using copper-mediated 1,3-dipolar cycloaddition. Obtained compounds exhibit good cytotoxicity against HBL100 epithelial cell lines (IC(50)=0.599-2.93 μМ). Several newly synthesized compounds are the substoichiometric inhibitors of microtubule assembly (R=0.41-0.78). The results highlight the importance of the length of spacer linking the tubulin binding ligands in heterodimeric molecules. 相似文献
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