Search Results (130)

Background: Chagas disease, caused by Trypanosoma cruzi, remains a major public health problem in Latin America and an emerging concern worldwide. Current chemotherapies show limited efficacy during chronic infection, and no licensed vaccine is currently available. We previously developed the chimeric antigen N-Tc52/TSKb20 as a vaccine candidate against T. cruzi infection. In a murine model, this vaccine induced robust antigen-specific immune response associated with protection shortly after vaccination. Objectives: Here, we investigated the long-term persistence and effector functions of the immune responses elicited by this vaccine candidate. Methods: Both female and male C57BL/6 mice were immunized with three doses of N-Tc52/TSKb20 formulated with QuilA adjuvant. Serum samples collected 170 days post-immunization were analyzed for antigen-specific antibodies by ELISA and for trypanolytic activity against cell-derived trypomastigotes using an in vitro functional assay. Cellular immune responses were evaluated by measuring cytokine production, T cell activation, and memory T cell responses following in vitro re-stimulation with the vaccine antigen or T. cruzi antigens. Results: N-Tc52/TSKb20 vaccination induced a sustained antigen-specific humoral response, characterized by long-lasting IgG2c antibodies and functional activity persisting for up to 170 days post-immunization. In parallel, vaccination promoted long-term activation of antigen-specific CD8⁺ T cells and production of TNF-α and IFN-γ upon antigen re-encounter. A sex-dependent tendency was observed for IL-10, with increased production in vaccinated female mice. Moreover, vaccinated animals exhibited increased frequencies of central and effector memory CD4⁺ and CD8⁺ T cells in response to T. cruzi antigens, with a predominant contribution of CD8⁺ T cells, indicating the establishment of parasite-specific T cell memory. Conclusions: Together, these findings demonstrate that vaccination with N-Tc52/TSKb20 induces a long-lasting Th1-biased immune response characterized by trypanolytic antibodies, functional and durable T cell responses, and parasite-specific memory T cells. This immunological profile supports the potential of N-Tc52/TSKb20 as a promising vaccine candidate for Chagas disease and highlights its capacity to elicit immune mechanisms that have been associated with protection against T. cruzi infection. Full article

Chagas disease affects millions of people worldwide, including those in Latin America. The only drugs available for its treatment are benznidazole and nifurtimox. However, these drugs present high toxicity and limited efficacy. Therefore, the search for new treatments continues. In this regard, computer-assisted drug design has been implemented in scientific research for drug repurposing, allowing for reduced costs and time. Therefore, the objective of this work was to search for analogs of FDA-approved drugs with activity against Trypanosoma cruzi through ligand-based virtual screening and their biological evaluation against blood trypomastigotes. The compound TD-095 (LC₅₀ = 48.60 and 13.75 µM), a ketanserin analogue, TS-936 (LC₅₀ = 71.55 and 37.54 µM), a terfenadine analogue, and TD-831 (LC₅₀ = 75.94 and 26.17 µM), a sulfasalazine analogue, were considered as potential trans-sialidase inhibitors; TIM-967 (LC₅₀ = 69.70 and 39.69 µM) and LK-284 (LC₅₀ = 116.7 and 82.29 µM), two sulfonylurea analogues, were considered as potential triosephosphate isomerase inhibitors, showing better trypanocidal activity against NINOA and INC-5 strains, respectively, than the reference drugs. Molecular dynamics simulations predicted the stability of the compounds in complex with their respective proteins. Finally, the ADMET predictive analysis showed favorable properties for the compounds. These results support continued research into new agents against Trypanosoma cruzi, using structures of drugs already approved by the FDA. Full article

In this study, a drug repurposing strategy was implemented with the aim of identifying new trypanocidal agents against Trypanosoma cruzi (T. cruzi). A total of 924 Food and Drug Administration (FDA)-approved drugs were screened by molecular docking on three sites of trypanothione synthetase (TS), including the catalytic site, a blind docking site, and a potential allosteric site. Selected compounds were further evaluated through in vitro and in vivo assays. Tadalafil, Zafirlukast, Raltegravir, and Olmesartan had better trypanocidal activity than the reference drugs Benznidazole and Nifurtimox in the in vitro evaluation against the trypomastigote form. Additionally, these drugs were able to decrease parasitemia by 20–50% in mice in an acute treatment. Molecular dynamics simulations (MDS) at 120 ns helped link findings from in vitro/in vivo experiments to a potential mechanism of action targeting T. cruzi trypanothione synthetase (TcTS). Therefore, the results encourage the use of these drugs to develop new anti-T. cruzi agents. Full article

The protozoan Trypanosoma cruzi is the etiological agent of Chagas disease, a neglected tropical disease that mostly affects the population of Latin American countries, with an estimated 7 million infected people and more than 10,000 deaths per year worldwide. T. cruzi is typically transmitted by hematophagous triatomine insects, with Rhodnius prolixus being a major insect vector in South America. While the microbiome of triatomine insects has been investigated to a certain extent, the ternary interaction between triatomes insects, T. cruzi, and viruses remains virtually unexplored. In this study, we show by transmission electron microscopy and by RT-PCR that Rhodnius prolixus viruses (RpVs) can infect the intestine of R. prolixus, which places them in close contact with the gut microbiota. These observations suggest that T. cruzi can be infected by the insect viruses while transiting through the gut. Here, we show that the RpVs are capable of infecting the epimastigote forms of T. cruzi in vitro and maintain the viral load stabilized for 3 to 7 days after infection. We also show that, at least in the case of the iFlavirus RpV1, viral genomes are detectable in the T. cruzi cytoplasm. Interestingly, R. prolixus ovarian extracts enriched with RpVs decrease epimastigote proliferation and their capacity for differentiation into the ineffective metacyclic trypomastigotes in vitro. Our results start to shed light on the interaction between RpVs and T. cruzi, suggesting possible routes of infection and unveiling a role for viral infections in the development of this important pathogen. Full article

Background: Chagas disease is a major public health problem, especially in Latin American countries, and benznidazole and nifurtimox are currently the only drugs available for its treatment. However, they present several disadvantages, such as low availability, high toxicity, and limited efficacy, which often result in treatment discontinuation. In recent decades, bioinformatics studies have accelerated the field of drug repurposing, reducing time and costs. In this study, the aim was to identify novel cruzain inhibitors from the analogs of FDA-approved drugs with trypanocidal activity. Methods: A ligand-based virtual screen, along with molecular docking analysis, was carried out, and the selected compounds were evaluated for their trypanocidal activity against trypomastigotes of two endemic Mexican strains and their inhibitory activity on cysteine proteases. Results: A cefsulodin analog (LC₅₀ = 126.18 and 77.50 µM), two flucloxacillin analogs (LC₅₀ = 94.05 and 101.73 µM; 48.74 and 64.49 µM), and one piperacillin analog (LC₅₀ = 48.46 and 83.68 µM) had better trypanocidal activity and selectivity index against the NINOA and INC-5 strains than the reference drugs. Enzymatic evaluation showed that all four compounds inhibited cysteine proteases (IC₅₀ < 840.03 µM). Furthermore, molecular dynamics simulations predicted the stability of the compound–protein complex, while the docking test on human cathepsin L predicted their potential selectivity. Finally, our in silico analysis of ADMET properties showed that all compounds exhibited favorable profiles. Conclusions: These results encourage the development of new and more potent anti-Trypanosoma cruzi agents using FDA-approved drugs as scaffolds. Full article

Background: Trypanosoma cruzi, the causative agent of Chagas disease, remains a major public health concern, and there is a continued need for new antitrypanosomal agents. Thiosemicarbazone (TSC) derivatives have emerged as a promising class of compounds with potential antiparasitic activity. Objectives: This study aimed to report the synthesis, characterization, and biological profiling of a novel series of thiosemicarbazone derivatives as antitrypanosomal agents against Trypanosoma cruzi. Methods: Fourteen new compounds and six previously described analogues were prepared and characterized by ¹H/¹³C nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). As a preliminary in vitro screen, activity was assessed by direct parasite counting in epimastigote and bloodstream trypomastigote forms, as tractable models of replicative and infective stages sharing core metabolic targets with intracellular amastigotes. Epimastigote potency was quantified as half-maximal effective concentrations (EC₅₀) derived from dose–response curves, whereas trypomastigote response was evaluated as percent viability after treatment at a fixed concentration of 20 µM. Mechanistic profiling included inhibition assays against the cysteine protease cruzipain (CZP) and selected redox defense enzymes, complemented by in silico similarity clustering and binding-pose affinity scoring. Results: A nitro-methoxy-substituted TSC showed potent CZP inhibition but limited trypomastigote efficacy, whereas brominated analogues displayed dual-stage activity independent of CZP inhibition. Tanimoto similarity analysis identified distinct structure–activity clusters, linking nitro-methoxy substitution to epimastigote selectivity and brominated scaffolds to broader antiparasitic profiles, with hydrophobicity and steric complementarity as key determinants. Enzymatic assays revealed no significant inhibition of cytosolic tryparedoxin peroxidase (cTXNPx) or glutathione peroxidase type I (TcGPx-I), suggesting redox disruption is not a primary mode of action. In vitro and in silico analyses showed low or no non-specific cytotoxicity under the tested conditions, supporting further optimization of these derivatives as antitrypanosomal preliminary hits. Key hits included derivative 3e (epimastigote EC₅₀ = 0.36 ± 0.02 µM) and brominated analogues 2c and 2e (epimastigote EC₅₀ = 3.92 ± 0.13 and 4.36 ± 0.10 µM, respectively), while docking supported favorable binding-pose affinity (e.g., ΔG_S-pose = −20.78 ± 2.47 kcal/mol for 3e). Conclusions: These results support further optimization of the identified thiosemicarbazone derivatives as preliminary antitrypanosomal hits and provide insight into structure–activity relationships and potential mechanisms of action. Full article

Chagas disease remains a significant neglected tropical disease that predominantly affects vulnerable populations in rural, low-income areas of Latin America. The management of this condition is severely hindered by the limitations of current therapies, which are characterized by substantial toxicity, diminished efficacy during the chronic phase, and the emergence of parasitic resistance. Given the promising activity of SB-83 (a 2-aminothiophenic derivative) against Leishmania spp., the present study sought to evaluate its trypanocidal activity against Trypanosoma cruzi. The results showed that SB-83 exhibited potent inhibitory effects on the epimastigote forms of T. cruzi (IC₅₀ = 6.23 ± 0.84 μM), trypomastigotes (EC₅₀ = 7.31 ± 0.52 μM) and intracellular amastigotes (EC₅₀ = 5.12 ± 0.49 μM). Furthermore, the cellular proliferation assay results indicated CC₅₀ values of 77.80 ± 2.05 µM for LLC-MK2 CCL-7 and 24.21 ± 1.2 µM for Vero CCL-87, with a selectivity index above 10 for LLC-MK2 cells. In addition, the compound increased TNF-α, IL-12, nitric oxide, and ROS while decreasing IL-10. Moreover, in silico and in vitro assays confirmed its binding to trypanothione reductase, disrupting redox balance. Flow cytometry further revealed apoptosis induction in trypomastigotes, whereas electron microscopy showed cellular disruption and organelle disorganization. Therefore, SB-83 demonstrated potent activity against the TcI-resistant strain linked to Chagas cardiomyopathy at non-toxic concentrations for host cells, supporting its potential as a therapeutic candidate. Full article

Chagas disease remains a major public health challenge due to the limited effectiveness and considerable side effects of existing treatments, particularly during the chronic stage. Açaí (Euterpe oleracea) seeds have gained increasing attention as a source of bioactive compounds with potential therapeutic applications. In this study, hydroalcoholic extracts and solvent fractions obtained from açaí seeds were chemically characterized by ESI/MS and HPLC–MS/MS and evaluated for their cytotoxicity and antiparasitic activity against different developmental stages of Trypanosoma cruzi (Y strain). Chemical profiling revealed a predominance of phenolic compounds, particularly catechins and procyanidins, which were identified as major constituents of the hydroalcoholic extract and the ethyl acetate fraction. Cytotoxicity assays performed on murine peritoneal macrophages demonstrated low toxicity, with CC₅₀ values exceeding 500 µg/mL for most samples, indicating a favorable in vitro safety profile. Antiparasitic assays showed weak activity against epimastigote forms; however, significant inhibitory effects were observed against bloodstream trypomastigotes, cell culture-derived trypomastigotes, and intracellular amastigotes. Notably, the hydroalcoholic extract exhibited the highest selectivity against intracellular amastigotes, with a selectivity index greater than 10, fulfilling key criteria proposed by the Drugs for Neglected Diseases initiative (DNDi) for early-stage hit compounds. Flow cytometry analysis showed that both the hydroalcoholic extract and the ethyl acetate fraction induced parasite cell death through late apoptosis-like and necrosis. Together, these findings highlight the antiparasitic potential of E. oleracea seed extracts, particularly against clinically relevant stages of T. cruzi, and support further investigation of these bioproducts as promising candidates for the development of new therapeutic strategies for Chagas disease. Full article

Trypanosoma cruzi is the causative agent of Chagas disease, which affects 6–7 million people worldwide. Although the possibility of oral transmission was first scientifically suggested in 1913, it was not until 1968 that the first confirmed cases of human infection via food consumption were reported. This long gap contributed to the widespread perception that oral transmission was a rare or incidental event. Over the past two decades, significant advances have been made in understanding the biological and clinical aspects of oral transmission, including the molecular mechanisms by which metacyclic trypomastigotes establish infection via the digestive route. Experimental studies in murine models have further deepened our knowledge of the biology and pathogenesis of oral infection. Concurrently, multiple outbreaks of T. cruzi infection through contaminated food and beverages have been reported across Latin America, providing valuable insights into the molecular epidemiology and clinical characteristics of this transmission route. Moreover, experimental evidence has shown that the consumption of meat from animals infected during the acute phase can also lead to T. cruzi infection, highlighting carnivory as a potential alternative transmission mechanism. This review aims to comprehensively analyze oral infection by T. cruzi, considering clinical and epidemiological data, parasite biology, and findings from murine experimental models. Strategies for controlling foodborne transmission of Chagas disease are also discussed. Full article

Chagas disease is caused by the protozoan Trypanosoma cruzi, and its current treatment is limited to the use of two nitroderivatives, benznidazole (Bz) and nifurtimox; however, their toxicity often leads to discontinuation, justifying the search for new therapeutic options. The biological activity of quinones has long shown efficacy towards pathogenic microorganisms. In our previous investigations, two naphthoquinones combining ortho- and para-quinoidal moieties exhibited remarkable trypanocidal activity and presented low toxicity to host cells. Here, these two active compounds were further assessed. On trypomastigotes and epimastigotes, brominated (NQ1) and chlorinated (NQ2) nor-beta-lapachone-derived 1,2,3-triazoles were more active than Bz, presenting IC₅₀/24 h values in the range of 0.8 to 3.1 µM. NQ1-treated epimastigotes showed a mitochondrial impairment and reactive oxygen species (ROS) production under electron microscopy and flow cytometry. The in vitro evaluation of both combinations of compounds with Bz indicated an additive interaction. In vivo, oral treatment with NQ1 reduced parasitemia in an acute model, with no evidence of toxicity. The treatment also led to a reduction in myocarditis, decreasing the PR interval in electrocardiographic analysis and reversing the sinus bradycardia caused by infection. These data suggest that T. cruzi mitochondrion are part of the NQ1 mechanism of action. In vivo, this compound presented moderate trypanocidal and promising anti-inflammatory activity. Its combination with Bz could enhance current therapeutic protocols and should be better explored in the future. Full article

Background/Objectives: Chagas disease, caused by Trypanosoma cruzi, remains a major neglected tropical disease with limited therapeutic options restricted to benznidazole and nifurtimox, both associated with significant toxicity and reduced efficacy during chronic infection. Seeking novel, safe, and sustainable chemotherapeutic candidates, two new saturated cardanol-derived phospholipid analogs—LDT10 and LDT119—were rationally designed based on the molecular scaffold of miltefosine and biosourced from cashew nut shell liquid (CNSL). This study aimed to evaluate the pharmacokinetic properties of these compounds in silico and assess their antiparasitic activity, cytotoxicity, and morphological and ultrastructural effects on all developmental forms of T. cruzi in vitro. Materials and Methods: In silico ADMET predictions (SwissADME, pkCSM) were performed to determine bioavailability, pharmacokinetic behavior, CYP inhibition, mutagenicity, and hepatotoxicity. Antiproliferative activity was evaluated in epimastigotes, trypomastigotes, and intracellular amastigotes using dose–response assays and flow cytometry. Cytotoxicity was assessed in HEPG2 and HFF-1 cells using resazurin-based viability assays. Morphological and ultrastructural alterations were investigated through scanning (SEM) and transmission (TEM) electron microscopy. Reactive oxygen species (ROS) generation was quantified with H₂DCFDA after 4 h and 24 h of exposure. Results: In silico analyses indicated favorable drug-like profiles, high intestinal absorption (>89%), absence of mutagenicity or hepatotoxicity, and non-penetration of the blood–brain barrier. LDT10 was not a P-gp substrate, and LDT119 acted as a P-gp inhibitor, suggesting reduced efflux and higher intracellular retention. Both compounds inhibited epimastigote proliferation with low IC₅₀ values (LDT10: 0.81 µM; LDT119: 1.2 µM at 48 h) and reduced trypomastigote viability (LD₅₀ LDT10: 2.1 ± 2 µM; LDT119: 1.8 ± 0.8 µM). Intracellular amastigotes were highly susceptible (IC₅₀ LDT10: 0.48 µM; LDT119: 0.3 µM at 72 h), with >90% inhibition at higher concentrations. No cytotoxicity was observed in mammalian cells up to 20 µM. SEM revealed membrane wrinkling, pore-like depressions, rounded cell bodies, and multiple flagella, indicating cell division defects. TEM showed Golgi disorganization, autophagic vacuoles, mitochondrial vesiculation, and abnormal kinetoplast replication, while host cells remained structurally preserved. Both compounds induced significant ROS production in trypomastigotes after 24 h in a dose-dependent manner. Conclusions: LDT10 and LDT119 exhibited potent and selective in vitro activity against all developmental stages of T. cruzi, with low micromolar to submicromolar IC₅₀/LD₅₀ values, minimal mammalian cytotoxicity, and extensive morphological and ultrastructural damage consistent with disruption of phospholipid biosynthesis pathways. Combined with favorable in silico pharmacokinetic predictions, these CNSL-derived phospholipid analogs represent promising candidates for future Chagas disease chemotherapy and warrant further in vivo evaluation. Full article

Trypanosoma cruzi, the causative agent of Chagas disease, can cross the placental barrier and be transmitted congenitally, yet the mechanisms underlying this process remain incompletely understood. Recent evidence suggests that T. cruzi-derived extracellular vesicles (TcEVs) may facilitate placental invasion by modulating host–pathogen interactions. In this study, we examined the effects of TcEVs on human placental explants (HPEs), focusing on their capacity to disrupt tissue architecture and modulate matrix metalloproteinases MMP-2 and MMP-9, enzymes critical for extracellular matrix remodeling. Term placental chorionic villi were cultured ex vivo and exposed to TcEVs, heat-inactivated TcEVs, infective trypomastigotes, or combinations thereof. TcEVs induced ultrastructural damage, including trophoblast detachment and basal lamina disorganization, which were exacerbated by co-incubation with parasites. Immunohistochemistry and Western blotting revealed significant upregulation of MMP-2 and MMP-9, while gelatin zymography confirmed increased enzymatic activity. Our findings demonstrate that TcEVs independently and synergistically with T. cruzi compromise placental integrity by enhancing MMP expression and activity, thereby priming the placental microenvironment for parasite invasion. Targeting TcEVs signaling or MMP activation may represent a novel strategy to prevent congenital transmission of T. cruzi. Full article

Oral infection is now the main route of Chagas disease transmission in endemic countries, with açaí (Euterpe oleracea) being the primary food involved in Brazil. However, the role of açaí in parasite–host interaction remains largely unexplored. This study assessed the effect of açaí inoculum on experimental Trypanosoma cruzi infection. BALB/c mice were orally infected with metacyclic trypomastigotes in RPMI or açaí. No difference in survival was observed. Tissue parasite load showed higher gastric parasitism in the RPMI group on day 5 after infection. Proteomic analysis of the açaí group revealed increased levels of cytoskeletal keratins and mucins, along with decreased pro-inflammatory cytokines and markers of tissue repair, indicating modulation of gastric inflammation. Both infected groups exhibited higher levels of gastrointestinal proteins (acid chitinase, gastrocin 1, trefoil) associated with mucosal protection and parasite clearance. These findings suggest that oral infection with açaí occurs more subtly, possibly due to decreased gastric inflammation, and highlight potential biomarkers for oral Chagas disease. Full article

Background/Objectives: Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi, which currently affects around 8 million people worldwide. The therapeutic arsenal against T. cruzi is so far limited to only two approved drugs, benznidazole and nifurtimox, that have considerable side effects and limited efficacy in the chronic stage of the disease. Here, we have resorted to supervised phenotypic machine learning models to explore drug repurposing opportunities and identify potential new therapeutic solutions for Chagas disease. Methods: More than 100,000 bioactivity data points were retrieved from ChEMBL and carefully curated according to the data-centric machine learning paradigm. After curation, two datasets comprising 344 compounds tested against T. cruzi Y strain trypomastigotes and 785 compounds tested against Tulahuen strain amastigotes were obtained and used to infer ensemble learning models with excellent average and early enrichment metrics in retrospective screening experiments (AUROC > 0.96 and EF_0.01 > 58). A prospective screening campaign was then performed on DrugBank and the Drug Repurposing Hub databases, submitting eight in silico hits for experimental confirmation. Results: Six of the in silico hits confirmed their predicted trypanocidal effects. Conclusions: We have built portable meta-classifiers capable of identifying small molecules with trypanocidal activity against amastigotes, the clinically most relevant stage of T. cruzi. The predictive ability of this meta-classifier was experimentally validated. Full article

Trypanosoma cruzi, the etiological agent of Chagas disease, exhibits remarkable developmental plasticity that enables its survival across distinct environments within the insect vector and mammalian host. This review focuses on two critical differentiation processes—metacyclogenesis and epimastigogenesis—emphasising their environmental triggers, metabolic regulation, and roles in parasite transmission and life cycle progression. Metacyclogenesis, occurring in the hindgut of triatomine vectors, transforms replicative epimastigotes into infective metacyclic trypomastigotes and is tightly controlled by factors such as nutrient starvation, pH, and temperature. In contrast, epimastigogenesis allows trypomastigotes to revert to epimastigote forms, primarily in the vector midgut, as part of the parasite’s adaptation to vector colonisation. We compare these processes through the lens of stress-induced signalling and proteomic reprogramming, highlighting their metabolic divergence and ecological significance. Emerging evidence also suggests that extracellular vesicles (EVs) released by different parasite forms may actively modulate these transitions, supporting parasite communication and immune evasion strategies. A better understanding of these transitions provides novel insight into parasite adaptation and reveals potential molecular targets for disrupting the life cycle of T. cruzi. Full article