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Fast and Specific Assessment of the Halogenating Peroxidase Activity in Leukocyte-enriched Blood Samples
Published on: July 28, 2016
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Leishmanicidal activity of peroxynitrite
R M Gatti1, O Augusto1, J K Kwee1
1a Department of Biochemistry , Instituto de Química, Universidade de São Paulo , São Paulo , Brazil and Department of Parasitology , Instituto de Biologia, UNICAMP , Campinas, SP , Brazil.
Redox Report : Communications in Free Radical Research
|July 14, 2016
Summary
Peroxynitrite effectively inhibits Leishmania amazonensis growth in both buffer and cell culture. This parasite killing is concentration-dependent and linked to thiol group oxidation.
Area of Science:
- Immunology
- Parasitology
- Biochemistry
Background:
- Nitric oxide and superoxide react to form peroxynitrite.
- Peroxynitrite shows variable microbicidal activity against protozoan parasites.
- Macrophages and neutrophils utilize peroxynitrite as a cytotoxic effector.
Purpose of the Study:
- To investigate the leishmanicidal effects of peroxynitrite on Leishmania amazonensis.
- To resolve conflicting reports on peroxynitrite's efficacy against different Leishmania species.
- To elucidate the mechanism of peroxynitrite-induced parasite death.
Main Methods:
- Culturing Leishmania amazonensis promastigotes.
- Treating parasites with varying concentrations of peroxynitrite in phosphate buffer and DMEM.
- Assessing parasite growth inhibition, motility, and morphology.
- Evaluating the effect of reduced glutathione on peroxynitrite activity.
Main Results:
- Peroxynitrite demonstrated concentration-dependent inhibition of Leishmania amazonensis growth.
- Significant growth inhibition (70%) occurred at 0.5 mM peroxynitrite in buffer.
- In cell culture (DMEM), 4 mM peroxynitrite caused 43% growth inhibition.
- Parasite motility decreased, and cells rounded, indicating leishmanicidal activity.
- Reduced glutathione attenuated peroxynitrite's effect, suggesting thiol oxidation is key.
Conclusions:
- Peroxynitrite exhibits potent leishmanicidal activity against Leishmania amazonensis.
- The mechanism involves oxidation of critical thiol groups within the parasite.
- These findings highlight peroxynitrite's potential role in host defense against leishmaniasis.
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