ABC Transporter May Be Involved in Heme Uptake in Trypanosoma cruzi Epimastigotes

CUPELLO, M. P.; SOUZA, C.F.; CORREA-SOARES, J.B.R.; LARANJA, G.A.T.; COELHO, M.G.P.; JULIA A CRICCO; MARCIA C PAES

Centro de Convenções do Hotel Rafain, Foz do Iguaçu, Paraná, Brasil.

Congreso; XXXIX Reunião Anual da Sociedade Brasileira de Bioquímica e Biologia Molecular – SBBq; 2010

Sociedade Brasileira de Bioquímica e Biologia Molecular – SBBq

ABC Transporter May Be Involved in Heme Uptake in Trypanosoma cruzi Epimastigotes Cupello, M. P.1*, Souza, C.F., Correa-Soares, J.B.R.2, Laranja, G.A.T.1, Coelho, M.G.P.1, Cricco, J.A.3 and Paes, M.C.1 1Departamento de Bioquímica, IBRAG – UERJ.2 Instituto de Bioquímica Médica – UFRJ.3Instituto de Biología Molecular y Celular de Rosario, IBR CONICET - UNR Trypanosoma cruzi, the etiological agent of Chaga’s disease, takes up heme from the environment to supply their nutritional needs, since it is not synthesized in epimastigotes. Heme is a porphyrin (Fe-protoporphyrin IX) that plays a critical role in several biological reactions such as oxygen transport and cell respiration. However, the mechanisms involved in its uptake across biological membranes are poorly understood. Indeed, in these parasites, no heme transporter has yet been characterized. Thus, here we evaluated the heme import by epimastigotes. Our results showed that when parasites were pre-loaded with other porphyrins such as  Sn-protoporphyrin IX, Pd-mesoporphyrin IX and Zn-mesoporphyrin IX the heme uptake decreased drastically. The same effects were observed when these parasites were treated with ATP- binding cassette (ABC) transporters blockers, verapamil, cyclosporin and indomethacin. Furthermore, we evaluated the effect of these drugs in epimastigotes growth kinetics and observed that, in contrast with heme, in the presence of heme plus these drugs the parasites growth decreased. These results suggest the existence of a mutual porphyrin carrier in T. cruzi epimastigotes, possibly an ABC-like transporter. Supported by CAPES, CNPQ and FAPERJ