Characterization of the proline uptake in different lineages of T. cruzi and T. brucei over-expressing or silenced for critical enzymes of the proline metabolism

Abstract

Proline is an important amino acid for protozoan parasite of the genus Trypanosoma and Leishmania, which include the causative agents of Chagas disease, African sleeping sickness and leishmanioses. It is also known that amino acid metabolism is particularly relevant in the interaction among these parasites and their invertebrate hosts, due to the fact that these metabolites are abundant in the insect´s hemolympha. In particular, proline is relevant, being the metabolic fuel for insect muscle-cells. In the ongoing collaboration, the laboratories of Prof. Silber and Prof. Alvaro are intending to get insights into the proline metabolism of T. cruzi as well as of T. brucei insect stages and their interaction in both, the parasite and the invertebrate hosts. The present proposal is part of a joint network project between Prof. Silber's and Prof. Acosta Serrano's groups, which general objective is to unveil the metabolic interactions between both trypanosome species and their invertebrate hosts. Part of this project is already running in Prof. Acosta Serrano's laboratory, at the Liverpool School of Tropical Medicine, and part will be run at Prof. Silber's laboratory at the University of São Paulo. Preliminary results showed that the enzyme delta-1-pyrroline 5-carboxylate dehydrogenase (P5CDH), a key component within the proline-glutamate pathway, is the rate limiting step of the reaction. The confirmation of this information is useful to modify the regulation of the proline metabolism in these parasites. Based on these possibilities T. cruzi and T. brucei strains over-expressing the P5CDH gene have been generated. Additionally, a P5CDH knocked-down T. brucei strain has also been obtained in Prof. Alvaro´s laboratory using the RNA interference technology. The intention of this application is to invite Prof. Alvaro Acosta Serrano for joining temporally my laboratory in order to measure the changes in the proline uptake of the three genetically modified parasites with respect to their controls in both organisms, T. cruzi and T. brucei. Besides, haemolymph from triatomines infected or not infected with the wild type strain as well as with P5CDH overexpressing T. cruzi will be isolated in order to apply metabolomic analysis using mass spectrometry in Prof. Alvaro´s laboratory. In relation to the analysis of the triatomine hemolymph, the samples will be analyzed together with hemolymph material obtained from tse-tse flies which carries wild type or genetically modified T. brucei parasites. (AU)