Disruptores heterocíclicos de la dimerización de la TryR de "L. infantum" como herramientas terapéuticas innovadoras

La leishmaniasis es una enfermedad tropical olvidada considerada como una de las más antiguas de la humanidad, a pesar de que el parásito de Leishmania causante de la patología, no fue descubierto hasta 1901 por William Leishman y Charles Donovan. Dicha especie catalogada como Leishmania donovani, es junto con la Leishmania infantum la responsable de la forma más agresiva de la enfermedad denominada leishmaniasis visceral o kala azar. La leishmaniasis representa tras la malaria, la segunda causa parasitaria de muerte con más de 50.000 defunciones al año. La enfermedad es endémica en más de 97 países. El arsenal de fármacos disponibles para el tratamiento de la leishmaniasis es escaso, obsoleto y presenta problemas de toxicidad y resistencias lo que justifica la urgente necesidad de desarrollar terapias novedosas más eficaces..

Observación de la distribución del manto de nieve con vehículos aéreos no tripulados sobre la transición entre el ambiente forestal y sub-alpino en el Pirineo aragonés.

Este es un trabajo enfocado al estudio del uso de vehículos aéreos no tripulados para la observación y estudio de la nieve. En ese sentido se pretende conocer la viabilidad de esta nueva tecnología en este campo de la investigación, intentando conocer qué tipo de resultados se pueden obtener con su uso. En zonas abiertas y desnudas dichos resultados han sido óptimos. Pero en contraposición, las zonas con presencia de vegetación arbórea mas o menos densas han supuesto impedimentos para la observación y estimación de los espesores de nieve hasta el momento. Ese es uno de los retos existentes en este tipo de estudios sobre la nieve, ya que la interacción entre el manto nivoso y la vegetación resulta de gran relevancia para conocer el espesor que puede haber bajo el dosel forestal, y la imposibilidad de verlo de forma directa presenta un problema que hasta el momento no se ha conseguido evitar. Así pues, con este trabajo se va a realizar un estudio de la nieve a través del uso de los drones sobre esas zonas para comprobar si se pueden conseguir estimaciones óptimas del espesor y la distribución de la nieve con las imágenes de gran resolución y las geolocalizaciones centimétricas que ofrecen.<br /

Pyrrolopyrimidine vs imidazole-phenyl-thiazole scaffolds in nonpeptidic dimerization inhibitors of leishmania infantum trypanothione reductase

Disruption of protein-protein interactions of essential oligomeric enzymes by small molecules represents a significant challenge. We recently reported some linear and cyclic peptides derived from an α-helical region present in the homodimeric interface of Leishmania infantum trypanothione reductase (Li-TryR) that showed potent effects on both dimerization and redox activity of this essential enzyme. Here, we describe our first steps toward the design of nonpeptidic small-molecule Li-TryR dimerization disruptors using a proteomimetic approach. The pyrrolopyrimidine and the 5-6-5 imidazole-phenyl-thiazole α-helix-mimetic scaffolds were suitably decorated with substituents that could mimic three key residues (K, Q, and I) of the linear peptide prototype (PKIIQSVGIS-Nle-K-Nle). Extensive optimization of previously described synthetic methodologies was required. A library of 15 compounds bearing different hydrophobic alkyl and aromatic substituents was synthesized. The imidazole-phenyl-thiazole-based analogues outperformed the pyrrolopyrimidine-based derivatives in both inhibiting the enzyme and killing extracellular and intracellular parasites in cell culture. The most active imidazole-phenyl-thiazole compounds 3e and 3f inhibit Li-TryR and prevent growth of the parasites at low micromolar concentrations similar to those required by the peptide prototype. The intrinsic fluorescence of these compounds inside the parasites visually demonstrates their good permeability in comparison with previous peptide-based Li-TryR dimerization disruptors.We thank the Spanish Government (MINECO/FEDER Projects SAF2015-64629-C2, BFU2017-90030-P), the Comunidad de Madrid (BIPEDD-2-CM ref S-2010/BMD-2457), and the Consejo Superior de Investigaciones Cientıfí cas (CSIC Project 201980E028) for financial support. We thank staff from ALBA Synchrotron (Barcelona, Spain) for support during data collection.Peer Reviewe

Identification of L. infantum trypanothione synthetase inhibitors with leishmanicidal activity from a (non-biased) in-house chemical library

Redox homeostasis in trypanosomatids is based on the low-molecular-weight trypanothione, an essential dithiol molecule that is synthetized by trypanothione synthetase (TryS) and maintained in its reduced state by trypa- nothione disulfide reductase (TryR). The fact that both enzymes are indispensable for parasite survival and absent in the mammalian hosts makes them ideal drug targets against leishmaniasis. Although many efforts have been directed to developing TryR inhibitors, much less attention has been focused on TryS. The screening of an in-house library of 144 diverse molecules using two parallel biochemical assays allowed us to detect 13 inhibitors of L. infantum TryS. Compounds 1 and 3 were characterized as competitive inhibitors with Ki values in the low micromolar range and plausible binding modes for them were identified by automated ligand docking against refined protein structures obtained through computational simulation of an entire catalytic cycle. The proposed binding site for both inhibitors overlaps the polyamine site in the enzyme and, additionally, 1 also occupies part of the ATP site. Compound 4 behaves as a mixed hyperbolic inhibitor with a Ki of 0.8 μM. The activity of 5 is clearly dependent on the concentration of the polyamine substrate, but its kinetic behavior is clearly not compatible with a competitive mode of inhibition. Analysis of the activity of the six best inhibitors against intracellular amastigotes identified 5 as the most potent leishmanicidal candidate, with an EC50 value of 0.6 μM and a selectivity index of 35.This work has been supported by the Spanish MICINN (Projects PID2019-104070RB-C21 and PID2019-104070RBC22), the Spanish National Research Council (CSIC, Projects CSIC-PIE-201980E100 and CSIC-PIE-201980E028), and the Comunidad de Madrid (PLATESA2-CM ref S-2018/BAA-4370). The MCIN is also acknowledged for the pre- doctoral fellowship to M.A.C.Peer reviewe

Identification of 1,2,3-triazolium salt-based inhibitors of Leishmania infantum trypanothione disulfide reductase with enhanced antileishmanial potency in cellulo and increased selectivity

N-methylation of the triazole moiety present in our recently described triazole-phenyl-thiazole dimerization disruptors of Leishmania infantum trypanothione disulfide reductase (LiTryR) led to a new class of potent in- hibitors that target different binding sites on this enzyme. Subtle structural changes among representative library members modified their mechanism of action, switching from models of classical competitive inhibition to time- dependent mixed noncompetitive inhibition. X-ray crystallography and molecular modeling results provided a rationale for this distinct behavior. The remarkable potency and selectivity improvements, particularly against intracellular amastigotes, of the LiTryR dimerization disruptors 4c and 4d reveal that they could be exploited as leishmanicidal agents. Of note, L. infantum promastigotes treated with 4c significantly reduced their low- molecular-weight thiol content, thus providing additional evidence that LiTryR is the main target of this novel compound.This work has been financially supported by the Spanish MICINN (Projects PID2019-104070RB-C21, PID2019-104070RB-C22 and PID2020-115331 GB-I00), the Spanish Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC, Projects CSIC-PIE-201980E100 and CSIC-PIE-201980E028), and the Comunidad de Madrid (PLATESA2-CM ref. S-2018/BAA-4370). The Spanish MEC is also acknowledged for FPU grants to A. R. and to J.C.G. P.A.S.M. thanks to the Division of Physio- logical Chemistry and the Otto-Loewi Research Center of the Medical University of Graz for their support with the scienfic cluster where the calculations contained in this work were run. We thank Ricardo Lau- reano-Rodríguez, Juan Antonio Rodríguez-Gutierrez, and Laura Lagar- tera for technical assistance with SPR experiments.Peer reviewe

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Dithienopyrrole as a rigid alternative to the bithiophene π relay in chromophores with second-order nonlinear optical properties

4H-Pyranylidene-containing push-pull chromophores built around a bithiophene (BT) π relay or a rigidified thiophene-based unit, namely cyclopenta[1,2-b:3,4-b′]dithiophene (CPDT) or dithieno[3,2-b:2′,3′-d]pyrrole (DTP), have been synthesized and characterized. The effect of these different relays on the polarization and the second-order nonlinear optical (NLO) properties has been studied. For the sake of comparison, the corresponding reported dithieno[3,2-b:2′,3′-d]thiophene (DTT) derivatives have also been included in the discussion. Replacement of the BT core by a rigidified unit (CPDT, DTP) leads to more polarized systems. Calculated NBO charges and electrochemical measurements show that dithienopyrrole has a remarkable donor character that allows an important charge transfer between the donor and the acceptor. The influence of the rigidification of the BT relay on the NLO responses depends on the acceptor strength. For the weakest acceptor used (thiobarbituric acid), passing from the BT relay to the rigidified units always involves an increase in the μβ0 figure of merit. Nevertheless, for the strongest acceptor (2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (TCF)), a slight increase in μβ0 with respect to the BT chromophore is only observed for the DTP derivative. Thus, rigidification of the BT core is not enough to improve the second-order nonlinearity and the incorporation of a DTP moiety has proven to be the most efficient approach for this purpose.Financial support from MICINN-FEDER (CTQ2011-22727 and MAT2011-27978-C02-02) and Gobierno de Aragón-Fondo Social Europeo (E39 and E04) is gratefully acknowledged. A predoctoral fellowship to A. B. Marco (FPI BES-2009-016966) is also acknowledged.Peer reviewe

Triazole-phenyl-thiazole heterocycles as innovative inhibitors of trypanothione reductase and their use as leishmanicides

The present invention refers to new compounds useful in the treatment of leishmaniasis and, more particularly, to a series of 5-6-5 triazole-phenyl-thiazole heterocycles capable of inhibiting both activity and dimerization of L. infantum TryR in enzymatic assays at low micromolar concentrations and endowed with potent in vitro activity against promastigote and amastigote forms of Leishmania which indicates a good permeability across the plasma membrane of the parasitesPeer reviewedConsejo Superior de Investigaciones Científicas (España), Universidad de AlcaláA1 Solicitud de patente con informe sobre el estado de la técnic

Triazole-phenyl-thiazole heterocycles as innovative inhibitors of trypanothione reductase and their use as leishmanicides

The present invention refers to new compounds useful in the treatment of leishmaniasis and, more particularly, to a series of 5-6-5 triazole-phenyl-thiazole heterocycles capable of inhibiting both activity and dimerization of L. infantum Try R in enzymatic assays at low micromolar concentrations and endowed with potent in vitro activity against promastigote and amastigote forms of Leishmania which indicates a good permeability across the plasma membrane ofthe parasitesPeer reviewedConsejo Superior de Investigaciones Científicas (España), Universidad de AlcaláA1 Solicitud de patente con informe sobre el estado de la técnic

Efficient Dimerization Disruption of Leishmania infantum Trypanothione Reductase by Triazole-phenyl-thiazoles

Inhibition of Leishmania infantum trypanothione disulfide reductase (LiTryR) by disruption of its homodimeric interface has proved to be an alternative and unexploited strategy in the search for novel antileishmanial agents. Proof of concept was first obtained by peptides and peptidomimetics. Building on previously reported dimerization disruptors containing an imidazole-phenyl-thiazole scaffold, we now report a new 1,2,3-triazole-based chemotype that yields noncompetitive, slow-binding inhibitors of LiTryR. Several compounds bearing (poly)aromatic substituents dramatically improve the ability to disrupt LiTryR dimerization relative to reference imidazoles. Molecular modeling studies identified an almost unexplored hydrophobic region at the interfacial domain as the putative binding site for these compounds. A subsequent structure-based design led to a symmetrical triazole analogue that displayed even more potent inhibitory activity over LiTryR and enhanced leishmanicidal activity. Remarkably, several of these novel triazole-bearing compounds were able to kill both extracellular and intracellular parasites in cell cultures.This work has been supported by the Spanish MICINN (Projects PID2019-104070RB-C21 and PID2019-104070RB- C22), the Spanish Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC, Projects CSIC-PIE- 201980E100 and CSIC-PIE-201980E028), and the Comuni- dad de Madrid (PLATESA2-CM ref S-2018/BAA-4370). The Spanish MEC is also acknowledged for FPU grants to A.R. and J.C.G.-S