Evidence for a cyanine link between propargylamine drugs and monoamine oxidase clarifies the inactivation mechanism

The authors acknowledge the financial support from the Slovenian Research Agency (research core funding No. P1-0005 and P1-0012). We thank COST CA15135 for facilitating collaboration on multi-target compounds and providing support for publication. Part of this work was also supported by the bilateral cooperation between the Royal Society of Edinburgh and the Slovenian Academy of Sciences and Arts and by COST Action CM1103 which facilitated short research visits in Ljubljana and St Andrews, respectively.Successful propargylamine drugs such as deprenyl inactivate monoamine oxidase (MAO), a target in multi-faceted approaches to prevent neurodegeneration in the aging population, but the chemical structure and mechanism of the irreversible inhibition are still debated. We characterized the covalent cyanine structure linking the multi-target propargylamine inhibitor ASS234 and the flavin adenine dinucleotide in MAO-A using a combination of ultra-high performance liquid chromatography, spectroscopy, mass spectrometry, and computational methods. The partial double bond character of the cyanine chain gives rise to 4 interconverting geometric isomers of the adduct which were chromatographically separated at low temperatures. The configuration of the cyanine linker governs adduct stability with segments of much higher flexibility and rigidity than previously hypothesized. The findings indicate the importance of intramolecular electrostatic interactions in the MAO binding site and provide key information relevant to incorporation of the propargyl moiety into novel multi-target drugs. Based on the structure, we propose a mechanism of MAO inactivation applicable to all propargylamine inhibitors.Publisher PDFPeer reviewe

Página web orientada a la evaluación “in silico” de nuevas sustancias con interés biológico

El principal objetivo que nos planteamos fue proporcionar a los alumnos, tanto de Grado cómo de Posgrado, un entorno de aprendizaje virtual adaptativo donde poner en práctica los conocimientos de toxicología adquiridos en las clases teóricas, complementando e incrementando así el conocimiento aplicado. Y que los alumnos adquieran experiencia práctica en el manejo de datos toxicológicos y herramientas virtuales que cada día están más presentes en la vida profesional, llevando a cabo procedimientos experimentales predictivos y evaluaciones toxicológicas in silico con herramientas reales. Para ello se planteó diseñar y elaborar una página web donde se engloben todos aquellos enlaces de herramientas validadas para realizar análisis toxicológicos on-line, y de esta manera, responder a la necesidad de crear un entorno de fácil acceso que incluya las numerosas herramientas a las que se puede acceder, con el valor añadido de los tutoriales o textos explicativos para su comprensión y utilización. Con todo ello, el principal objetivo es lograr que los alumnos aprendan, no solo a cómo usar e interpretar los datos, sino también a la aplicación potencial de dichos datos obtenidos a través de los sistemas in silico

Página web orientada a la evaluación “in silico” de nuevas sustancias con interés biológico. Parte II

Sección Deptal. de Farmacología y Toxicología (Veterinaria)Fac. de VeterinariaFALSEsubmitte

PP2A ligand ITH12246 protects against memory impairment and focal cerebral ischemia in mice

ITH12246 (ethyl 5-amino-2-methyl-6,7,8,9-tetrahydrobenzo[b][1,8] naphthyridine-3-carboxylate) is a 1,8-naphthyridine described to feature an interesting neuroprotective profile in in vitro models of Alzheimer's disease. These effects were proposed to be due in part to a regulatory action on protein phosphatase 2A inhibition, as it prevented binding of its inhibitor okadaic acid. We decided to investigate the pharmacological properties of ITH12246, evaluating its ability to counteract the memory impairment evoked by scopolamine, a muscarinic antagonist described to promote memory loss, as well as to reduce the infarct volume in mice suffering phototrombosis. Prior to conducting these experiments, we confirmed its in vitro neuroprotective activity against both oxidative stress and Ca2+ overload-derived excitotoxicity, using SH-SY5Y neuroblastoma cells and rat hippocampal slices. Using a predictive model of blood-brain barrier crossing, it seems that the passage of ITH12246 is not hindered. Its potential hepatotoxicity was observed only at very high concentrations, from 0.1 mM. ITH12246, at the concentration of 10 mg/kg i.p., was able to improve the memory index of mice treated with scopolamine, from 0.22 to 0.35, in a similar fashion to the well-known Alzheimer's disease drug galantamine 2.5 mg/kg. On the other hand, ITH12246, at the concentration of 2.5 mg/kg, reduced the phototrombosis-triggered infarct volume by 67%. In the same experimental conditions, 15 mg/kg melatonin, used as control standard, reduced the infarct volume by 30%. All of these findings allow us to consider ITH12246 as a new potential drug for the treatment of neurodegenerative diseases, which would act as a multifactorial neuroprotectant.Peer Reviewe

Evidence for a cyanine link between propargylamine drugs and monoamine oxidase clarifies the inactivation mechanism

Successful propargylamine drugs such as deprenyl inactivate monoamine oxidase (MAO), a target in multi-faceted approaches to prevent neurodegeneration in the aging population, but the chemical structure and mechanism of the irreversible inhibition are still debated. We characterized the covalent cyanine structure linking the multi-target propargylamine inhibitor ASS234 and the flavin adenine dinucleotide in MAO-A using a combination of ultra-high performance liquid chromatography, spectroscopy, mass spectrometry, and computational methods. The partial double bond character of the cyanine chain gives rise to 4 interconverting geometric isomers of the adduct which were chromatographically separated at low temperatures. The configuration of the cyanine linker governs adduct stability with segments of much higher flexibility and rigidity than previously hypothesized. The findings indicate the importance of intramolecular electrostatic interactions in the MAO binding site and provide key information relevant to incorporation of the propargyl moiety into novel multi-target drugs. Based on the structure, we propose a mechanism of MAO inactivation applicable to all propargylamine inhibitors

Donepezil-like multifunctional agents: Design, synthesis, molecular modeling and biological evaluation

Currently available drugs against Alzheimer's disease (AD) are only able to ameliorate the disease symptoms resulting in a moderate improvement in memory and cognitive function without any efficacy in preventing and inhibiting the progression of the pathology. In an effort to obtain disease-modifying anti-Alzheimer's drugs (DMAADs) following the multifactorial nature of AD, we have recently developed multifunctional compounds. We herein describe the design, synthesis, molecular modeling and biological evaluation of a new series of donepezil-related compounds possessing metal chelating properties, and being capable of targeting different enzymatic systems related to AD (cholinesterases, ChEs, and monoamine oxidase A, MAO-A). Among this set of analogues compound 5f showed excellent ChEs inhibition potency and a selective MAO-A inhibition (vs MAO-B) coupled to strong complexing properties for zinc and copper ions, both known to be involved in the progression of AD. Moreover, 5f exhibited moderate antioxidant properties as found by in vitro assessment. This compound represents a novel donepezil-hydroxyquinoline hybrid with DMAAD profile paving the way to the development of a novel class of drugs potentially able to treat AD

Synthesis and biological assessment of new pyrimidopyrimidines as inhibitors of breast cancer resistance protein (ABCG2)

International audienc

A reinvestigation of the acid-promoted heterocyclization of 2-(2-oxo-2-arylethyl)malononitriles in the presence of amines

The reinvestigation of the acid-promoted cyclization of 2-(2-oxo-2-arylethyl)malononitriles, in the presence of benzylamine or aniline, in ethanol or acetonitrile, has confirmed that this is a long-time reaction process for a low-yielding synthesis of 2-amino-5-arylfuran-3-carbonitriles (2), or 2-amino-5-aryl-1-phenyl-1H-pyrrole-3-carbonitriles (4), depending on the base used. However, the microwave-assisted synthesis of 2-amino-5-(4'-methoxyphenyl)furan-3(4)-(di)carbonitriles (2c and 3c) proceeds in shorter reaction times and higher yields than does the classical thermal heating protocol. In these reactions we have observed for the first time, and characterized by their spectroscopic data and X-ray analysis, the unexpected formation of 2-amino-5-aryl-3 (4)-(di)carbonitriles (3), whose formation has been rationalized by density functional theory (DFT) analysis of the proposed reaction mechanism.. - Portuguese Foundation for Science and Technology (FCT) [SFRH/BD/17577/2004]; MEC [SAF2006-08764-C02-01]; Comunidad deMadrid [S/SAL-0275-2006]; Instituto de Salud Carlos III [RD06/0026/1002]; CSIC-GRICES project [2007PT13]. - This work was supported by the Portuguese Foundation for Science and Technology (FCT) funds as well as by C. M. Ph. D. fellowship SFRH/BD/17577/2004. M. C. C. thanks Carolina Duarte and Paula Santos for technical assistance. The present work has been supported by MEC Grants SAF2006-08764-C02-01, Comunidad deMadrid (S/SAL-0275-2006), Instituto de Salud Carlos III [Retic RENEVAS (RD06/0026/1002)], and CSIC-GRICES project (2007PT13)