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Damage of Trypanosoma cruzi deoxyribonucleic acid by nitroheterocyclic drugs
Abstract:
Kinetoplast DNA (kDNA) from Trypanosoma cruzi epimastigotes pretreated with the trypanocidal drugs nifurtimox (10 or 100 microM) or benznidazole (38 or 380 microM) showed an increased number of strand-breaks, as revealed by (a) trapping of alkali-denatured kDNA by nitrocellulose filters and (b) electrophoresis in an alkaline 2% agarose gel. Similar damage was observed in nuclear DNA (nDNA), as detected by centrifugation in an alkaline-sucrose gradient. DNA damage was reversible since reincubation in fresh medium for 24 hr restored filtration and electrophoretic and sedimentation patterns to normal.
Insights
Trypanocidal drugs like nifurtimox and benznidazole cause reversible DNA strand breaks in Trypanosoma cruzi. This damage to kinetoplast DNA and nuclear DNA can be repaired when the parasite is returned to a normal environment.
Area of Science:
- Molecular Biology
- Parasitology
- Drug Discovery
Background:
- Trypanosoma cruzi causes Chagas disease, a significant global health concern.
- Kinetoplast DNA (kDNA) is a unique mitochondrial DNA structure essential for trypanosomatids.
- Nifurtimox and benznidazole are established drugs for treating Chagas disease, but their precise mechanisms on DNA require further elucidation.
Purpose of the Study:
- To investigate the effects of nifurtimox and benznidazole on DNA integrity in Trypanosoma cruzi epimastigotes.
- To determine if DNA damage induced by these drugs is specific to kDNA or also affects nuclear DNA (nDNA).
- To assess the reversibility of drug-induced DNA damage.
Main Methods:
- Treatment of T. cruzi epimastigotes with varying concentrations of nifurtimox or benznidazole.
- Analysis of kDNA strand-breaks using nitrocellulose filter trapping of alkali-denatured kDNA.
- Assessment of kDNA damage via alkaline 2% agarose gel electrophoresis.
- Detection of nDNA damage using centrifugation in an alkaline-sucrose gradient.
- Evaluation of DNA repair by reincubating treated parasites in fresh medium.
Main Results:
- Nifurtimox and benznidazole treatments significantly increased strand-breaks in T. cruzi kinetoplast DNA (kDNA).
- Similar DNA strand-break damage was observed in the nuclear DNA (nDNA) of treated parasites.
- The observed DNA damage was reversible, with normal DNA structures restored after 24 hours of reincubation in fresh medium.
Conclusions:
- Nifurtimox and benznidazole induce significant, reversible DNA strand-breaks in both kDNA and nDNA of Trypanosoma cruzi.
- These findings provide insights into the DNA-damaging mechanism of these trypanocidal drugs.
- The reversibility of DNA damage suggests potential for host recovery or parasite adaptation.