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Quimioterapia antiparasitaria

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CREA TU PERFIL Grupo de Investigación
Grupo de Investigación
Otros Consejo Superior de Investigaciones Científicas (CSIC)
El grupo desarrolla su línea de investigación en el campo de las enfermedades parasitarias.Nuestro ... fundamentalmente del diseño y la síntesis de nuevas moléculas activas contra parásitos patógenos, especialmente por parásitos tripanosomátidos (Leishmania spp., T. cruzi, T. brucei spp.).

Christophe Dardonville
Líneas de Investigación Líneas de Investigación
Quimioterapia antiparasitaria de zoonosis
El grupo desarrolla la línea de investigación “New chemical entities for drug discovery” en el campo de las enfermedades parasitarias, especialmente las producidas por protozoos patógenos. Desde su creación, el grupo ha desarrollado varias series de compuestos químicos muy activos frente a diversos protozoos parásitos (T. cruzi, T. brucei spp., T. vaginalis, Leishmania spp., Plasmodium spp.). Varios prototipos demostraron también eficacia in vivo en modelos animales (ratón) de tripanosomiasis, leishmaniasis y de malaria. En la actualidad el grupo prosigue el estudio de estos prototipos, así como el desarrollo de otros nuevos, diseñados para atacar dianas específicas de estos parásitos. El grupo se ocupa fundamentalmente del diseño y la síntesis de nuevas moléculas activas, y cuenta con la colaboración de otros grupos españoles e internacionales (químicos computacionales, bioquímicos, parasitólogos, tecnólogos farmacéuticos, cristalografos) para alcanzar sus objetivos.
Proyectos de Investigación Proyectos de Investigación
Desarrollo de farmacos dirigidos a la mitocondria y organulos similares como enfoque terapeutico para el tratamiento de enfermedades parasitarias desatendidas
Año: 2018
Convocatoria: Proyectos de I+D+i «Retos investigación» del Programa Estatal de I+D+i Orientada a los Retos de la Sociedad
Patentes Patentes
Compuestos derivados de 4-amino-N-(4-aminofenil)benzamida y análogos y uso de los mismos
Código de la patente: ESP202230181
Sales de 4-hidroxifenil fosfonio con propiedades antiparasitarias
Código de la patente: PCT/ES2020/070421
Publicaciones Publicaciones
New benzophenone-derived bisphosphonium salts as leishmaniccidal leads targeting mitochondria through inhibition of respiratory complex II
A set. of benzophenone-derived bisphosphonium salts was synthesized and assayed for lethal activity on the human protozoan parasite Leishmania. A subset of them, mostly characterized by phosphonium substituents with an intermediate hydrophobicity, inhibited parasite proliferation at low micromolar range of concentrations. The best of this subset, 4, 4`̌prime;-bis((tri-n- pentylphosphonium)methyl)benzophenone dibromide, showed a very scarce toxicity on mammalian, cells. This compound targets complex II of the respiratory chain, of the parasite, based on, (i) a dramatically swollen mitochondrion in treated parasites, (ii) fast decrease of cytoplasmic ATP, (iii) a decrease of the electrochemical mitochondrial potential, and, (iv) inhibition of the oxygen consumption rate using succinate as substrate. Thus, this type of compounds represents a new lead in the development of leishmanicidal drugs.
Antiprotozoal activity and DNA binding of dicationic acridones
Two series of N-alkyl, N-alkoxy, and N-hydroxy bisguanidines derived from the N-phenylbenzamide and 1,3-diphenylurea scaffolds were synthesised in three steps from the corresponding 4-amino-N-(4-aminophenyl)benzamide and 1,3-bis(4-aminophenyl)urea, respectively. All of the new compounds were evaluated in vitro against T. b. rhodesiense (STIB900) trypomastigotes and Plasmodium falciparum NF54 parasites (erythrocytic stage). N-alkoxy and N-hydroxy derivatives showed weak micromolar range IC50 values against T. b. rhodesiense and P. falciparum whereas the N-alkyl analogues displayed submicromolar and low nanomolar IC50 values against P. falciparum and Trypanosoma brucei, respectively. Two compounds, 4-(2-ethylguanidino)-N-(4-(2-ethylguanidino)phenyl)benzamide dihydrochloride (7b) and 4-(2-isopropylguanidino)-N-(4-(2-isopropylguanidino)phenyl)benzamide dihydrochloride (7c), which showed favourable drug-like properties and in vivo efficacy (100% cures) in the STIB900 mouse model of acute human African trypanosomiasis represent interesting leads for further in vivo studies. The binding of these compounds to AT-rich DNA was confirmed by surface plasmon resonance (SPR) biosensor experiments.
Alternative oxidase inhibitors: Mitochondrion-targeting as a strategy for new drugs against pathogenic parasites and fungi
The alternative oxidase (AOX) is a ubiquitous terminal oxidase of plants and many fungi, catalyzing the four-electron reduction of oxygen to water alongside the cytochrome-based electron transfer chain. Unlike the classical electron transfer chain, however, the activity of AOX does not generate adenosine triphosphate but has functions such as thermogenesis and stress response. As it lacks a mammalian counterpart, it has been investigated intensely in pathogenic fungi. However, it is in African trypanosomes, which lack cytochrome-based respiration in their infective stages, that trypanosome alternative oxidase (TAO) plays the central and essential role in their energy metabolism. TAO was validated as a drug target decades ago and among the first inhibitors to be identified was salicylhydroxamic acid (SHAM), which produced the expected trypanocidal effects, especially when potentiated by coadministration with glycerol to inhibit anaerobic energy metabolism as well. However, the efficacy of this combination was too low to be of practical clinical use. The antibiotic ascofuranone (AF) proved a much stronger TAO inhibitor and was able to cure Trypanosoma vivax infections in mice without glycerol and at much lower doses, providing an important proof of concept milestone. Systematic efforts to improve the SHAM and AF scaffolds, aided with the elucidation of the TAO crystal structure, provided detailed structure-activity relationship information and reinvigorated the drug discovery effort. Recently, the coupling of mitochondrion-targeting lipophilic cations to TAO inhibitors has dramatically improved drug targeting and trypanocidal activity while retaining target protein potency. These developments appear to have finally signposted the way to preclinical development of TAO inhibitors.
Synthesis, biological, and photophysical studies of molecular rotor-based fluorescent inhibitors of the Trypanosome Alternative Oxidase
We have recently reported on the development and trypanocidal activity of a class of inhibitors of Trypanosome Alternative Oxidase (TAO) that are targeted to the mitochondrial matrix by coupling to lipophilic cations via C14 linkers to enable optimal interaction with the enzyme’s active site. This strategy resulted in a much-enhanced anti-parasite effect, which we ascribed to the greater accumulation of the compound at the location of the target protein, i.e. the mitochondrion, but to date this localization has not been formally established. We therefore synthesized a series of fluorescent analogues to visualize accumulation and distribution within the cell. The fluorophore chosen, julolidine, has the remarkable extra feature of being able to function as a viscosity sensor and might thus additionally act as a probe of the cellular glycerol that is expected to be produced when TAO is inhibited. Two series of fluorescent inhibitor conjugates incorporating a cationic julolidine-based viscosity sensor were synthesized and their photophysical and biological properties were studied. These probes display a red emission, with a high signal-to-noise ratio (SNR), using both single- and two-photon excitation. Upon incubation with T. brucei and mammalian cells, the fluorescent inhibitors 1a and 2a were taken up selectively in the mitochondria as shown by live-cell imaging. Efficient partition of 1a in functional isolated (rat liver) mitochondria was estimated to 66 ± 20% of the total. The compounds inhibited recombinant TAO enzyme in the submicromolar (1a, 2c, 2d) to low nanomolar range (2a) and were effective against WT and multidrug-resistant trypanosome strains (B48, AQP1-3 KO) in the submicromolar range. Good selectivity (SI > 29) over mammalian HEK cells was observed.
Descubrimiento y estudio farmacológico de sales de fosfonio derivadas del 4-hidroxifenilo con actividad en un modelo murino de leishmaniasis visceral
We report the discovery of new 4-hydroxyphenyl phosphonium salt derivatives active in the submicromolar range (EC50 from 0.04 to 0.28 μM, SI > 10) against the protozoan parasite Leishmania donovani. The pharmacokinetics and in vivo oral efficacy of compound 1 [(16-(2,4-dihydroxyphenyl)-16 - oxohexadec yl)triphenylphosphonium bromide] in a mouse model of visceral leishmaniasis were established. Compound 1 reduced the parasite load in spleen (98.9%) and liver (95.3%) of infected mice after an oral dosage of four daily doses of 1.5 mg/kg. Mode of action studies showed that compound 1 diffuses across the plasma membrane, as designed, and targets the mitochondrion of Leishmania parasites. Disruption of the energetic metabolism, with a decrease of intracellular ATP levels as well as mitochondrial depolarization together with a significant reactive oxygen species production, contributes to the leishmanicidal effect of 1. Importantly, this compound was equally effective against antimonials and miltefosine-resistant clinical isolates of Leishmania infantum, indicating its potential as antileishmanial lead.
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