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In vivo uptake of a haem analogue Zn protoporphyrin IX by the human malaria parasite P. falciparum-infected red blood cells
Robson Sartorello*, Alexandre Budu†, Piero Bagnaresi*, Carlos AH Fernandes§, Paloma M Sato*, Vânia B Bueno‡, Marcos RM Fontes§, Pedro L Oliveira║, Gabriela O Paiva‑Silva║, Simone V Alves¶, Luis ES Netto¶, Luiz H Catalani‡ and Celia RS Garcia*1
*Departamento de Fisiologia, Instituto de Biocincias, Universidade de So Paulo, Rua do Mato, Travessa 14, no 321, 05508900 So Paulo, SP, Brazil, †Departamento de Parasitologia, Instituto de Cincias Biomdicas, Universidade de So Paulo, Rua do Mato, Travessa 14, no 321, 05508900 So Paulo, SP, Brazil, ‡Departamento de Qumica Fundamental, Instituto de Qumica, Universidade de So Paulo, Rua do Mato, Travessa 14, no 321, 05508900 So Paulo, SP, Brazil, §Departamento de Fsica e Biofsica, Instituto de Biocincias, Universidade Estadual Paulista Jlio de Mesquita Filho, Botucatu, SP, Brazil, ║Instituto de Bioqumica Mdica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, and ¶Departamento de Biologia, Instituto de Biocincias, Universidade de So Paulo, Rua do Mato, Travessa 14, no 321, 05508900 So Paulo, SP, Brazil
The cellular traffic of haem during the development of the human malaria parasite Plasmodium falciparum, through the stages R (ring), T (trophozoite) and S (schizonts), was investigated within RBC (red blood cells). When Plasmodium cultures were incubated with a fluorescent haem analogue, ZnPPIX (Zn protoporphyrin IX) the probe was seen at the cytoplasm (R stage), and the vesicle-like structure distribution pattern was more evident at T and S stages. The temporal sequence of ZnPPIX uptake by P. falciparum-infected erythrocytes shows that at R and S stages, a time-increase acquisition of the porphyrin reaches the maximum fluorescence distribution after 60 min; in contrast, at the T stage, the maximum occurs after 120 min of ZnPPIX uptake. The difference in time-increase acquisition of the porphyrin is in agreement with a maximum activity of haem uptake at the T stage. To gain insights into haem metabolism, recombinant PfHO (P. falciparum haem oxygenase) was expressed, and the conversion of haem into BV (biliverdin) was detected. These findings point out that, in addition to haemozoin formation, the malaria parasite P. falciparum has evolved two distinct mechanisms for dealing with haem toxicity, namely, the uptake of haem into a cellular compartment where haemozoin is formed and HO activity. However, the low Plasmodium HO activity detected reveals that the enzyme appears to be a very inefficient way to scavenge the haem compared with the Plasmodium ability to uptake the haem analogue ZnPPIX and delivering it to the food vacuole.
Key words: cellular traffic, confocal microscopy, haem oxygenase, malaria, Plasmodium
Abbreviations: BV, biliverdin, HO, haem oxygenase, R, ring, RBC, red blood cells, S, schizont, T, trophozoite, ZnPPIX, Zn protoporphyrin IX
1To whom correspondence should be addressed (email firstname.lastname@example.org).
Received 8 December 2009/15 April 2010; accepted 21 May 2010
Published as Cell Biology International Immediate Publication 21 May 2010, doi:10.1042/CBI20090427
© The Author(s) Journal compilation © 2010 Portland Press Limited