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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 caused by the protozoan Trypanosoma cruzi (T. cruzi). It remains the major parasitic disease in Latin America and is spreading worldwide, affecting over 10 million people. Hundreds of new compounds with trypanosomicidal action have been identified from different sources such as synthetic or natural molecules, but they have been deficient in several stages of drug development (toxicology, scaling-up, and pharmacokinetics). Previously, we described a series of compounds with simple structures, low cost, and environmentally friendly production with potent trypanosomicidal activity in vitro and in vivo. These molecules are from three different families: thiazolidenehydrazines, diarylideneketones, and steroids. From this collection, we explored their capacity to inhibit the triosephosphate isomerase and cruzipain of T. cruzi. Then, the mechanism of action was explored using NMR metabolomics and computational molecular dynamics. Moreover, the mechanism of death was studied by flow cytometry. Consequently, five compounds, 314, 793, 1018, 1019, and 1260, were pre-clinically studied and their pharmacologic profiles indicated low unspecific toxicity. Interestingly, synergetic effects of diarylideneketones 793 plus 1018 and 793 plus 1019 were evidenced in vitro and in vivo. In vivo, the combination of compounds 793 plus 1018 induced a reduction of more than 90% of the peak of parasitemia in the acute murine model of Chagas disease.

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.

Background: Canine multicentric lymphomas are lymphoproliferative malignancies that have increased in recent decades. The patient’s treatment and prognosis are determined by the grade, histological type, and lymphoma immunophenotyping. Aim: To investigate the paraclinical signs and survival time in canines with different lymphoma immunophenotypes. Methods: Over 2 and a half years, 47 untreated dogs were diagnosed with multicentric lymphoma at the Veterinary School Hospital of Uruguay. The disease was clinically and cytologically diagnosed, and immunophenotyping was determined by flow cytometry. After the immunophenotyping, most of the patients were grouped into the following: B (LB), T aggressive (LTCD45+), or T-zone lymphoma (LTCD45−). The patients’ haematological values, calcemia, lactate dehydrogenase (LDH) levels, and plasmatic electrophoretic profiles were all determined immediately after that. Results: Of all canine lymphomas, 55.3% were B, 31.9% were LTCD45+, and 10.6% were TCD45−. Only 2.2% were classified as nonB/nonT, and survival time differed between groups. Patients with LTCD45− lymphomas had a mean life span of 641 days after diagnosis, followed by LB (166 days) and LTCD45+ (62 days). Red blood cell count, hematocrit, and hemoglobin levels did not differ between groups. However, the LTCD45− group had significantly higher lymphocyte levels than the LTCD45+ and LB groups (p = 0.01 and 0.006, respectively). Levels of albumin, alpha-1, and alpha-2 globulins did not differ between groups. On the other hand, gamma globulins levels in the LTCD45− were higher than in the other lymphoma groups. The presence of hypercalcemia and high plasma LDH levels were associated with patient severity. Only the TCD45+ group had hypercalcemia although both the LB and TCD45+ groups had elevations in LDH activity. Interestingly, there was a direct relationship between high LDH values (greater than 500 IU/l) and lower survival in TCD45+ lymphomas. Conclusion: Survival time and hematological and biochemical patterns differed among canine lymphomas immunophenotypes. Patients of LTCD45− phenotype showed higher lymphocyte counts and gamma globulin levels and more prolonged survival. Serum LDH activity may provide additional prognostic information in high-grade T-cell lymphoma.

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.