Search

The antibacterial properties of close noscapine analogs have not been previously reported. We used our pDualrep2 double-reporter High Throughput Screening (HTS) platform to identify a series of noscapine derivatives with promising antibacterial activity. The platform is based on RPF (SOS-response/DNA damage) and Katushka2S (inhibition of translation) proteins and simultaneously provides information on antibacterial activity and the mechanism of action of small-molecule compounds against E. coli. The most potent compound exhibited an MIC of 13.5 µM(6.25 µg/ml) and a relatively low cytotoxicity against HEK293 cells (CC 50  = 71 µM, selectivity index: ~5.5). Some compounds from this series induced average Katushka2S reporter signals, indicating inhibition of translation machinery in the bacteria; however, these compounds did not attenuate translation in vitro in a luciferase-based translation assay. The most effective compounds did not significantly arrest the mitotic cycle in HEK293 cells, in contrast to the parent compound in a flow cytometry assay. Several molecules showed activity against clinically relevant gram-negative and gram-positive bacterial strains. Compounds from the discovered series can be reasonably regarded as good templates for further development and evaluation., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

A series of 5-oxo-4H-pyrrolo[3,2-b]pyridine derivatives was identified as novel class of highly potent antibacterial agents during an extensive large-scale high-throughput screening (HTS) program utilizing a unique double-reporter system-pDualrep2. The construction of the reporter system allows us to perform visual inspection of the underlying mechanism of action due to two genes-Katushka2S and RFP-which encode the proteins with different imaging signatures. Antibacterial activity of the compounds was evaluated during the initial HTS round and subsequent rescreen procedure. The most active molecule demonstrated a MIC value of 3.35 µg/mL against E. coli with some signs of translation blockage (low Katushka2S signal) and no SOS response. The compound did not demonstrate cytotoxicity in standard cell viability assay. Subsequent structural morphing and follow-up synthesis may result in novel compounds with a meaningful antibacterial potency which can be reasonably regarded as an attractive starting point for further in vivo investigation and optimization.

Background: The key issue in the development of novel antimicrobials is a rapid expansion of new bacterial strains resistant to current antibiotics. Indeed, World Health Organization has reported that bacteria commonly causing infections in hospitals and in the community, e.g. E. Coli, K. pneumoniae and S. aureus, have high resistance vs the last generations of cephalosporins, carbapenems and fluoroquinolones. During the past decades, only few successful efforts to develop and launch new antibacterial medications have been performed. This study aims to identify new class of antibacterial agents using novel high-throughput screening technique., Methods: We have designed library containing 125K compounds not similar in structure (Tanimoto coeff.< 0.7) to that published previously as antibiotics. The HTS platform based on double reporter system pDualrep2 was used to distinguish between molecules able to block translational machinery or induce SOS-response in a model E. coli system. MICs for most active chemicals in LB and M9 medium were determined using broth microdilution assay., Results: In an attempt to discover novel classes of antibacterials, we performed HTS of a large-scale small molecule library using our unique screening platform. This approach permitted us to quickly and robustly evaluate a lot of compounds as well as to determine the mechanism of action in the case of compounds being either translational machinery inhibitors or DNA-damaging agents/replication blockers. HTS has resulted in several new structural classes of molecules exhibiting an attractive antibacterial activity. Herein, we report as promising antibacterials. Two most active compounds from this series showed MIC value of 1.2 (5) and 1.8 μg/mL (6) and good selectivity index. Compound 6 caused RFP induction and low SOS response. In vitro luciferase assay has revealed that it is able to slightly inhibit protein biosynthesis. Compound 5 was tested on several archival strains and exhibited slight activity against gram-negative bacteria and outstanding activity against S. aureus. The key structural requirements for antibacterial potency were also explored. We found, that the unsubstituted carboxylic group is crucial for antibacterial activity as well as the presence of bulky hydrophobic substituents at phenyl fragment., Conclusion: The obtained results provide a solid background for further characterization of the 5'- (carbonylamino)-2,3'-bithiophene-4'-carboxylate derivatives discussed herein as new class of antibacterials and their optimization campaign., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

The present report describes our efforts to identify new structural classes of compounds having promising antibacterial activity using previously published double-reporter system pDualrep2. This semi-automated high-throughput screening (HTS) platform has been applied to perform a large-scale screen of a diverse small-molecule compound library. We have selected a set of more than 125,000 molecules and evaluated them for their antibacterial activity. On the basis of HTS results, eight compounds containing 2-pyrazol-1-yl-thiazole scaffold exhibited moderate-to-high activity against ΔTolC Escherichia coli. Minimum inhibitory concentration (MIC) values for these molecules were in the range of 0.037-8 μg ml -1 . The most active compound 8 demonstrated high antibacterial potency (MIC = 0.037 μg ml -1 ), that significantly exceed that measured for erythromycin (MIC = 2.5 μg ml -1 ) and was comparable with the activity of levofloxacin (MIC = 0.016 μg ml -1 ). Unfortunately, this compound showed only moderate selectivity toward HEK293 eukaryotic cell line. On the contrary, compound 7 was less potent (MIC = 0.8 μg ml -1 ) but displayed only slight cytotoxicity. Thus, 2-pyrazol-1-yl-thiazoles can be considered as a valuable starting point for subsequent optimization and morphing.

Many pharmaceutical companies are avoiding the development of novel antibacterials due to a range of rational reasons and the high risk of failure. However, there is an urgent need for novel antibiotics especially against resistant bacterial strains. Available in silico models suffer from many drawbacks and, therefore, are not applicable for scoring novel molecules with high structural diversity by their antibacterial potency. Considering this, the overall aim of this study was to develop an efficient in silico model able to find compounds that have plenty of chances to exhibit antibacterial activity. Based on a proprietary screening campaign, we have accumulated a representative dataset of more than 140,000 molecules with antibacterial activity against Escherichia coli assessed in the same assay and under the same conditions. This intriguing set has no analogue in the scientific literature. We applied six in silico techniques to mine these data. For external validation, we used 5,000 compounds with low similarity towards training samples. The antibacterial activity of the selected molecules against E. coli was assessed using a comprehensive biological study. Kohonen-based nonlinear mapping was used for the first time and provided the best predictive power (av. 75.5%). Several compounds showed an outstanding antibacterial potency and were identified as translation machinery inhibitors in vitro and in vivo . For the best compounds, MIC and CC 50 values were determined to allow us to estimate a selectivity index (SI). Many active compounds have a robust IP position.

Aim and Objective: Antibiotic resistance is a serious constraint to the development of new effective antibacterials. Therefore, the discovery of the new antibacterials remains one of the main challenges in modern medicinal chemistry. This study was undertaken to identify novel molecules with antibacterial activity., Materials and Methods: Using our unique double-reporter system, in-house large-scale HTS campaign was conducted for the identification of antibacterial potency of small-molecule compounds. The construction allows us to visually assess the underlying mechanism of action. After the initial HTS and rescreen procedure, luciferase assay, C14-test, determination of MIC value and PrestoBlue test were carried out., Results: HTS rounds and rescreen campaign have revealed the antibacterial activity of a series of Nsubstituted triazolo-azetidines and their isosteric derivatives that has not been reported previously. Primary hit-molecule demonstrated a MIC value of 12.5 µg/mL against E. coli Δ tolC with signs of translation blockage and no SOS-response. Translation inhibition (26%, luciferase assay) was achieved at high concentrations up to 160 µg/mL, while no activity was found using C14-test. The compound did not demonstrate cytotoxicity in the PrestoBlue assay against a panel of eukaryotic cells. Within a series of direct structural analogues bearing the same or bioisosteric scaffold, compound 2 was found to have an improved antibacterial potency (MIC=6.25 µg/mL) close to Erythromycin (MIC=2.5-5 µg/mL) against the same strain. In contrast to the parent hit, this compound was more active and selective, and provided a robust IP position., Conclusion: N-substituted triazolo-azetidine scaffold may be used as a versatile starting point for the development of novel active and selective antibacterial compounds., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Introduction: A variety of organic compounds has been reported to have antibacterial activity. However, antimicrobial resistance is one of the main problems of current anti-infective therapy, and the development of novel antibacterials is one of the main challenges of current drug discovery., Methods: Using our previously developed dual-reporter High-Throughput Screening (HTS) platform, we identified a series of furanocoumarins as having high antibacterial activity. The construction of the reporter system allows us to differentiate three mechanisms of action for the active compounds: inhibition of protein synthesis (induction of Katushka2S), DNA damaging (induction of RFP) or other (inhibition of bacterial growth without reporter induction)., Results: Two primary hit-molecules of furanocoumarin series demonstrated relatively low MIC values comparable to that observed for Erythromycin (Ery) against E. coli and weakly induced both reporters. Dose-dependent translation inhibition was shown using in vitro luciferase assay, however it was not confirmed using C14-test. A series of close structure analogs of the identified hits was obtained and investigated using the same screening platform. Compound 19 was found to have slightly lower MIC value (15.18 µM) and higher induction of Katushka2S reporter in contrast to the parent structures. Moreover, translation blockage was clearly identified using both in vitro luciferase assay and C14 test. The standard cytotoxicity test revealed a relatively low cytotoxicity of the most active molecules., Conclusion: High antibacterial activity in combination with low cytotoxicity was demonstrated for a series of furanocoumarins. Further optimization of the described structures may result in novel and attractive lead compounds with promising antibacterial efficiency., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Asialoglycoprotein receptor (ASGP-R) is a promising biological target for drug delivery into hepatoma cells. Nevertheless, there are only few examples of small-molecule conjugates of ASGP-R selective ligand equipped by a therapeutic agent for the treatment of hepatocellular carcinoma (HCC). In the present work, we describe a convenient and versatile synthetic approach to novel mono- and multivalent drug-conjugates containing N-acetyl-2-deoxy-2-aminogalactopyranose and anticancer drug - paclitaxel (PTX). Several molecules have demonstrated high affinity towards ASGP-R and good stability under physiological conditions, significant in vitro anticancer activity comparable to PTX, as well as good internalization via ASGP-R-mediated endocytosis. Therefore, the conjugates with the highest potency can be regarded as a promising therapeutic option against HCC., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

We studied the effects of single treatment with ladasten (50 mg/kg) on the content of effector kinases of the mitogen-activated cascade (ERK1/ERK2), pERK1/ERK2 activity (Thr202/Tyr204), and expression of genes for neurotrophic factors BDND and NGF in the striatum, hypothalamus, and hippocampus of rats.

The goal of the current work is to study the molecular mechanisms underlay the action of 5- amino-exo-3-azatricyclo[5.2.1.0(2,6)]decan-4-one (P-11) with combined antiarrhythmic, nootropic, anti-inflammatory and anaesthetic activities. The aconitine-induced experimental rat model of cardiac arrhythmia has been used in our study. Aconitine was administered once intravenously in a dose 50 microg/kg whereas experimental animal group received P-11 in a dose 0.3 mg/kg (the compound was injected intravenously 2 min before acute aconitine treatment). Expression macroarray (Atlas Rat cDNA Expression Array, #7738-1; BD Biosciences) was used to identify the target genes for P-11 compound. Comparative analysis of changes in the status of expression of genes in the heart of rats induced by P-11 against the simulated in vivo arrhythmia identified 16 genes that reproducibly alter the level of expression.These genes encode the extracellular matrix proteins (glypican 1, Gpc1; tissue inhibitor of metalloproteinase 2, 3, Timp2, Timp 3); intracellular signaling molecules (rho GTPase activating protein 7, Dlc1; protein tyrosine phosphatase 4a1, Ptp4a1; phosphodiesterase 4D, PDE4D; PI3-kinase regulatory subunit alpha, PIK3R1; guanine nucleotide binding protein alpha 12, Gna12) and protein of intermediate junctions (junction plakoglobin, Jup), proteins involved in glycolysis (phosphofructokinase I, Pfk1) and hemostasis (tissue plasminogen activator, Plat), plasma membrane transporters (Solute carrier family 16, member 1, Slc16a1; ATPase, Na+/K+ transporting, Atp1a), and ets. (c-fos protooncogene, c-fos; telomerase protein component 1, tlp; Annexin 1, anxa 1). Thus, the data about the selective effect of P-11 on genes whose products are involved in the aritmogenesys mechanisms, allow us to consider this compound as a promising means of pathogenetically oriented pharmacotherapy of cardiac arrhythmias.

Elevation of intracellular Ca²⁺ in T-lymphocytes as a consequence of T cell antigen receptor activation triggers transcriptional programs resulting in effector cytokine secretion and immune response coordination. Increase of Ca²⁺ concentration in T-lymphocytes follows both the Ins(1,4,5)P(3)-dependent release from an intracellular store and subsequent influx from extracellular milieu. Flow cytometry and the fluorescent dye Fluo-4AM have been used to demonstrate that noncompetitive NMDA receptor antagonist (+)-MK801 inhibits Ca²⁺ influx in T cells induced by thapsigargin. Combination of thapsigargin and (+)-MK801 with following incubation does not affect Ca²⁺ mobilization from intracellular stores, while decreased Ca²⁺ entry was observed. Overall data indicate that the ion channel blocker (+)-MK801 is able to inhibit the Ca²⁺ influx and confirm our suggestion about involvement of NMDA receptor in the store-operated Ca²⁺ entry mechanisms in human T-lymphocytes. To identify the signal transduction pathways associated with NMDA receptors in mitogen-stimulated T-lymphocytes, the cells were incubated with (+)-MK801, then activity of key phosphorylated protein kinases of MAP-activated (pERK1/2, pSAPK/JNK, p-p38), Ca²⁺-dependent (pCaMKII), PI3/Akt-dependent (pGSK-3β), and PKC-activated (pPKCθ) pathways were detected. The data we obtained demonstrate that (+)-MK801 treatment leads to more prominent decrease in Ras-activated protein kinases pERK1/2 and Rac-activated proteins p-p38 and pSAPK/JNK, as compared to DAG-dependent pPKCθ and Ca²⁺-dependent pCaMKII. These results show that NMDA receptors are mainly involved in regulation of Ras/Rac-dependent signaling in T-lymphocytes.

We studied the effects of single intragastric administration of ladasten in a dose of 50 mg/kg on the time course of histone deacetylase 1 (HDAC1) and levels of acetylated histones H3 (Lys9) and H4 (Lys8) in the striatum, hippocampus, and hypothalamus. Ladasten reduced HDAC1 level in rat striatum and hippocampus and modified H3acK9 and H4acK8 levels in various structures of rat brain.

Two-dimensional electrophoresis and mass spectrometry detection were used to evaluate the range of proteins in rat brain after single treatment with ladasten (50 mg/kg). We identified 13 proteins with various levels of expression.

We studied the effects of single administration of ladasten (50 mg/kg) on the level of transcriptional factor CREB (cyclic AMP response binding element protein) phosphorylated by Ser133 in rat striatum, hypothalamus, and hippocampus. Transcriptional factors with affected DNA-binding activity were identified in brain cells.

Derivatives of adamantane, like memantine, are potentially neuroprotective drugs for the favourable care of Alzheimer's and Parkinson's diseases. A further adamantane derivate is N-(2-adamantyl)-N-(para-bromophenyl)-amine (ladasten) which is capable to modulate animal performance in different learning paradigms. To clarify if some of those behavioural alterations are mediated by modulation of catecholamine syntheses we studied the effects of single administration of ladasten (50 mg/kg, per os) on catecholamines' biosynthesis in the ventral tegmental area, nucleus accumbens, hypothalamus, striatum and hippocampus. We found that ladasten differentially regulates tyrosine hydroxylase mRNA and protein as well as dopamine and L-DOPA content. We then investigated the effects of ladasten on activity-dependent hippocampal synaptic plasticity in vitro and found that application of 10 microM ladasten transforms short-term potentiation of synaptic transmission to a long-lasting form. A transformation of short-term into long-term potentiation was also observed, when ladasten was applied 40 min after a single 100 Hz 200 ms tetanization. This reinforcement was blocked by the protein synthesis inhibitor anisomycin and could be attenuated by the D1/D5 receptor antagonist SCH23390. These results suggest that ladasten induces reinforcement of short-term potentiation via protein synthesis and dopamine dependent mechanisms.