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Peroxynitrite affects Ca2+ transport in Trypanosoma cruzi
L Thomson1, F R Gadelha, G Peluffo
1Departamento de Bioquimica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
Molecular and Biochemical Parasitology
|February 24, 1999
Summary
Peroxynitrite, produced by macrophages during Trypanosoma cruzi infection, disrupts parasite calcium uptake and homeostasis. This disruption of calcium balance contributes to the parasite
Area of Science:
- Immunology
- Parasitology
- Cell Biology
Background:
- Macrophages are crucial in combating Trypanosoma cruzi infection through reactive oxygen and nitrogen species.
- Peroxynitrite exhibits significant cytotoxicity against Trypanosoma cruzi epimastigotes.
- Intracellular calcium regulation is vital for parasite functions and involves complex transport systems.
Purpose of the Study:
- To investigate the impact of peroxynitrite on calcium uptake systems in Trypanosoma cruzi.
- To elucidate the mechanisms by which peroxynitrite affects parasite calcium homeostasis.
Main Methods:
- Digitonin-permeabilized Trypanosoma cruzi were used to study calcium uptake in the presence of arsenazo III.
- Mitochondrial membrane potential was assessed using tetramethyl-p-phenylenediamine (TMPD)/ascorbate.
- High-performance liquid chromatography (HPLC) was employed to analyze cellular adenine nucleotide pools.
Main Results:
- Peroxynitrite significantly inhibited calcium uptake in a dose-dependent manner at biologically relevant concentrations.
- A decrease in mitochondrial membrane potential and non-mitochondrial Ca(2+)-uptake was observed.
- Peroxynitrite led to the inactivation of Ca(2+)-dependent ATPase activity and a delayed decrease in parasite ATP levels.
Conclusions:
- Peroxynitrite disrupts calcium homeostasis in Trypanosoma cruzi by inhibiting calcium uptake and affecting ATP-dependent transport.
- The disruption of calcium balance by peroxynitrite contributes to its cytotoxic effects on the parasite.