Abstract
Background
The obligate intracellular protozoan Trypanosoma cruzi is the causative agent of Chagas disease, a neglected illness affecting millions of people in Latin America that recently entered non-endemic countries through immigration, as a consequence of globalization. The chemotherapy for this disease is based mainly on benznidazole and nifurtimox, which are very efficient nitroderivatives against the acute stage but present limited efficacy during the chronic phase. Our group has been studying the trypanocidal effects of naturally occurring quinones and their derivatives, and naphthoimidazoles derived from β-lapachone N1, N2 and N3 were the most active. To assess the molecular mechanisms of action of these compounds, we applied proteomic techniques to analyze treated bloodstream trypomastigotes, which are the clinically relevant stage of the parasite.
Methodology/Principal Findings
The approach consisted of quantification by 2D-DIGE followed by MALDI-TOF/TOF protein identification. A total of 61 differentially abundant protein spots were detected when comparing the control with each N1, N2 or N3 treatment, for 34 identified spots. Among the differentially abundant proteins were activated protein kinase C receptor, tubulin isoforms, asparagine synthetase, arginine kinase, elongation factor 2, enolase, guanine deaminase, heat shock proteins, hypothetical proteins, paraflagellar rod components, RAB GDP dissociation inhibitor, succinyl-CoA ligase, ATP synthase subunit B and methionine sulfoxide reductase.
Conclusion/Significance
Our results point to different modes of action for N1, N2 and N3, which indicate a great variety of metabolic pathways involved and allow for novel perspectives on the development of trypanocidal agents.
Trypanosoma cruzi is the etiological agent of Chagas disease, an important illness for Latin American countries that is now afflicting other continents due to the immigration of infected people. The available chemotherapy is limited to the chronic phase of the disease, being the development of novel active compounds essential, and the search for specific molecular targets for drugs in T. cruzi is necessary. In this context, our group has synthesized and screened many compounds ranging from natural to semi-synthetic naphthoquinones and derivatives on T. cruzi, displaying naphthoimidazoles N1, N2 and N3 the highest activity. Previous studies correlated phenotypic alterations by cell biology techniques as well as investigated mode of action by proteomic approaches in insect stage epimastigotes as a model. However, T. cruzi presents three morphologically distinct life stages with their own specific biological peculiarities and requirements that could be potential targets to drug intervention. Here, we evaluated the mechanism of action of N1, N2 and N3 in clinical relevant form of the parasite, bloodstream trypomastigotes, by proteomics. Our data pointed to 61 differentially abundant protein spots, being these proteins involved with cellular trafficking, protein synthesis, transduction signaling and energetic metabolism, among others, open interesting perspectives for trypanocidal strategies.
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