Search

There is an urgent need to develop new drugs against Chagas’ disease. In addition, the mechanisms of action of existing drugs have not been completely worked out at the molecular level. High throughput approaches have been demonstrated to be powerful tools not only for understanding the basic biology of Trypanosoma cruzi, but also for the identification of drug targets such as proteins or pathways that are essential for parasite infection and survival within the mammalian host. Here, we have applied these tools towards the discovery of the effects of two organometallic compounds with trypanocidal activity, Pd–dppf–mpo and Pt–dppf–mpo, on the transcriptome and proteome of T. cruzi epimastigotes. These approaches have not yet been reported for any other prospective metal-based anti T. cruzi drug. We found differentially expressed transcripts and proteins in treated parasites. Pd–dppf–mpo treatment resulted in more modulated transcripts (2327 of 10 785 identified transcripts) than Pt–dppf–mpo treatment (201 of 10 773 identified transcripts) suggesting a mechanism of action for Pd–dppf–mpo at the transcriptome level. Similar numbers of differentially expressed proteins (342 and 411 for Pd–dppf–mpo and Pt–dppf–mpo respectively) were also observed. We further functionally categorized differentially expressed transcripts and identified cellular processes and pathways significantly impacted by treatment with the compounds. Transcripts involved in DNA binding, protein metabolism, transmembrane transport, oxidative defense, and the ergosterol pathways were found to be modulated by the presence of the compounds. Our transcriptomic dataset also contained previously validated essential genes. These data allowed us to hypothesize a multimodal mechanism of action for the trypanocidal activity of Pd–dppf–mpo and Pt–dppf–mpo, and a differential contribution of the metal moiety of each compound.

Chagas disease is an endemic illness in Latin America caused by the parasite Trypanosoma cruzi. Current chemotherapies are old and inadequate, and the emergence of drug-resistant strains underscores the need of new drugs. Platinum-based complexes have been shown to be a promising approach against parasitic diseases. In this work, the effect of 1,1'-bis(diphenylphosphino)ferrocene pyridine-2-thiolate-1-oxide Pt(II) hexafluorophosphate, Pt-dppf-mpo, was studied on T. cruzi. A promising antitrypanosomal activity was determined for the CL Brener strain with a low cytotoxicity determined using in vitro-cultured mammal cells. The compound uptake in parasites treated with concentrations of 1× and 10× the IC50 value reached ~75% and 19%, respectively. Pt-dppf-mpo induced necrosis after 24 hr of parasite incubation. This event was preceded by depolarization of mitochondrial membrane potential. Cell vitality assays showed high esterase activity in treated parasites. However, despite this increase in metabolic activity, treated epimastigotes showed rounded morphology and loss of flagellum with a reduction in mobility as compound concentration and/or time of incubation was increased. At last, we demonstrate that Pt-dppf-mpo incubation also affects the trypomastigote infection process as well as the infection persistence evaluated as the number of amastigotes per cell in a dose-dependent manner.

In Latin America Chagas disease is an endemic illness caused by the parasite Trypanosoma cruzi (T. cruzi), killing more people than any other parasitic disease. Current chemotherapies are old and inadequate, thus the development of efficient ones is urgently needed. Vanadium-based complexes have been shown to be a promising approach both against parasitic diseases and cancer and this study aims to achieve significant advances in the pursue of effective compounds. Heteroleptic vanadium complexes of Schiff bases and polypyridine compounds were prepared and their stability in solution evaluated by EPR (Electronic Paramagnetic Resonance) and NMR spectroscopy. Their in vitro activities were evaluated against T. cruzi and a set of cells lines representative of human cancer conditions, namely ovarian, breast and prostate cancer. In T. cruzi, most of the complexes depicted IC50 values in the low μM range, induced changes of mitochondrial membrane potential and apoptosis. In cancer cells, complexes showed good to moderate activity and in metastatic cells (prostate PC3), some complexes inhibited the migratory ability, this suggesting that they display antimetastatic potential. Interestingly, complex 5 seemed to have a dual effect being the most cytotoxic complex on all cancer cells and also the most active anti-T-cruzi compound of the series. Globally the complexes showed promising anticancer and anti T. cruzi activities and also displayed some characteristics indicating they are worth to be further explored as antimetastatic drugs.

Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. It is estimated that 6 million people are infected in Latin America. Current treatment is not effective due to the severe side effects and the limited efficacy towards the chronic phase of the disease. Considering the growing need for specific anti-Trypanosoma cruzi drugs, organometallic Pt and Pd based compounds were previously synthesized. Although the Pt-based compound effects on T. cruzi death have been reported, no mechanism of action has been proposed for the Pd-based analogous compound. In this work, we determined excellent to very good values of IC50 and SI. To analyze the compound mode of action, we measured Pd uptake and its association to the macromolecules of the parasite by electrothermal atomic absorption spectrometry. We found a poor uptake, which reaches only 16% after 24 h of incubation using 10× IC50, being the scarce incorporated metal preferentially associated to DNA. However, this compound has a trypanocidal effect, leading to morphological changes such as shortening of the parasite cell body and inducing necrosis after 24 h of treatment. Furthermore, this compound impairs the parasite development in the host both at the trypomastigote infection process and the intracellular amastigotes replication. In conclusion, our findings support that Pd-dppf-mpo compound constitutes a promising anti-T. cruzi compound effective against the chronic phase of the disease.

Chagas disease is caused by the parasite Trypanosoma cruzi (T. cruzi). It remains the major parasitic disease in Latin America, despite recent advances in the control of its vector-borne and transfusion mediated transmission. Moreover, migration of infected people has spread the disease to non-endemic areas, presenting a new worldwide challenge. The chemotherapy employed to control the parasitic infection is based on two drugs: Nifurtimox (Nfx) and Benznidazole (Bnz), requiring long-term treatment that can give rise to severe side effects. They are not active against all T. cruzi strains, exhibit low efficiency in long-term chronic infections, and are mutagenic. The search of new drugs is an urgent need. In this work, we used three symmetrical diarylideneketones containing thiophene and furane ((1E,3E,6E,8E)-1,9-Di(furan-2-yl)nona-1,3,6,8-tetraen-5-one (1), (2E,6E)-2,6-Bis((E)-3-(furan-2-yl)allylidene)cyclohexanone (2) and (2E,5E)-2,5-Bis[3-(thiophen-2-yl)allyliden]cyclopentanone (3)). These molecules showed good to excellent trypanosomicidal activity and selectivity to the parasite, affected cruzipain, a proteolytic enzyme of the parasite, and the glycolytic enzyme, triosephosphate isomerase of T. cruzi (TcTIM) without affecting human´s TIM and showing effectiveness in protecting infected mice and without toxic effects in vivo. In addition, these could be obtained by a simple and economic green synthetic route, which is an important feature in the research and development of future drugs for neglected diseases. The type of T. cruzi death caused is an important feature to determine, because it could govern inflammation events unbeneficial in the elimination of the parasite. We studied the mechanism of T. cruzi death using Annexin V and propidium iodide followed by flow cytometry analysis of epimastigote treated with the arylideneketones (1, 2, and 3). The arylideneketones along with Nfx and Bnz were evaluated at 24 h post- incubation with the parasite at 5X, 10X and 20X IC50. Arylidenketones 1 and 2 causes after 24 h late apoptosis/necrosis at a concentration of 20 times the value of its IC50 (approximately 80% of late apoptosis/necrosis) as Nfx. This necrotic effect of Nfx was also observed in our previous study by TUNNEL and 1H NMR. It should be studied what happens with compound 3 since no death is observed by apoptosis or necrosis at a dose of 20 times the value of their IC50 as Bnz. Probably, an autophagy process could be ongoing. Currently, we are performing studies in this sense. Acknowledgments: This work was supported by CSIC, PEDECIBA and Elena Aguilera is recipient of a ANII doctoral fellowship.

In search of prospective agents against infectious diseases, 1,1′-bis(diphenylphosphino)ferrocene pyridine-2-thiolato-1-oxide M(II) hexafluorophosphate compounds [M(mpo)(dppf)](PF6), where M = palladium or platinum, were synthesized and fully characterized in the solid state and in solution using experimental and DFT computational techniques. The compounds are isomorphous and the M(II) transition metal ions are in a nearly planar trapezoidal cis-coordination bound to the pyridine-2-thiolato-1-oxide (mpo) and to the 1,1′-bis(diphenylphosphino)ferrocene molecules, both acting as bidentate ligands. Both compounds showed high cytotoxic activity on Trypanosoma cruzi and Mycobacterium tuberculosis (MTB) and acceptable selectivities towards MTB, but good to excellent selectivity index values as anti-T. cruzi compounds. The inclusion of the ferrocene moiety (dppf ligand) improved the selectivity towards the parasite when compared to the previously reported [M(mpo)2] complexes. Related to the probable mechanism of action of the complexes, molecular docking studies on modelled T. cruzi NADH-fumarate reductase (TcFR) predicted that both be very good inhibitors of the enzyme. The effect of the compounds on the enzyme activity was experimentally confirmed using T. cruzi protein extracts. According to all obtained results, both [M(mpo)(dppf)](PF6) compounds could be considered prospective anti-trypanosomal agents that deserve further research. Fil: Rodríguez Arce, Esteban. Universidad de la República; Uruguay Fil: Mosquillo, M. Florencia. Universidad de la República; Uruguay Fil: Pérez Díaz, Leticia. Universidad de la República; Uruguay Fil: Echeverría, Gustavo Alberto. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina Fil: Piro, Oscar Enrique. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina Fil: Merlino, Alicia. Universidad de la República; Uruguay Fil: Coitiño, E. Laura. Universidad de la República; Uruguay Fil: Maríngolo Ribeiro, Camila. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Leite, Clarice Q. F.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Pavan, Fernando R.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Otero, Lucía. Universidad de la República; Uruguay Fil: Gambino, Dinorah. Universidad de la República; Uruguay