Mechanism of Trypanosoma cruzi death induced by Cratylia mollis seed lectin.
Incubation of T. cruzi epimastigotes with the lectin Cramoll 1,4 in Ca(2+) containing medium led to agglutination and inhibition of cell proliferation. The lectin (50 microg/ml) induced plasma membrane permeabilization followed by Ca(2+) influx and mitochondrial Ca(2+) accumulation, a result that resembles the classical effect of digitonin. Cramoll 1,4 stimulated (five-fold) mitochondrial reactive oxygen species (ROS) production, significantly decreased the electrical mitochondrial membrane potential (Delta Psi(m)) and impaired ADP phosphorylation. The rate of uncoupled respiration in epimastigotes was not affected by Cramoll 1,4 plus Ca(2+) treatment, but oligomycin-induced resting respiration was 65% higher in treated cells than in controls. Experiments using T. cruzi mitochondrial fractions showed that, in contrast to digitonin, the lectin significantly decreased Delta Psi(m) by a mechanism sensitive to EGTA. In agreement with the results showing plasma membrane permeabilization and impairment of oxidative phosphorylation by the lectin, fluorescence microscopy experiments using propidium iodide revealed that Cramoll 1,4 induced epimastigotes death by necrosis.
Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil.
M P
MP
Fernandes
N M
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Inada
M R
MR
Chiaratti
F F B
FF
Araújo
F V
FV
Meirelles
M T S
MT
Correia
L C B B
LC
Coelho
M J M
MJ
Alves
F R
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Gadelha
A E
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Vercesi
D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004072:Digitonin / Q000494:pharmacology; D007887:Fabaceae / Q000737:chemistry*; D006001:Glycoconjugates / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D009336:Necrosis; D010085:Oxidative Phosphorylation / Q000187:drug effects; D037121:Plant Lectins / Q000302:isolation & purification / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014349:Trypanosoma cruzi / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
D006001:Glycoconjugates; D037121:Plant Lectins; D017382:Reactive Oxygen Species; D004072:Digitonin