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Caenorhabditis elegans as a Model System for Studying Drug Induced Mitochondrial Toxicity.

de Boer R, Smith RL, De Vos WH, Manders EM, Brul S, van der Spek H - PLoS ONE (2015)

Bottom Line: The continuous intake of antiretroviral drugs however, leads to severe and even life-threatening side effects, supposedly by the deleterious impact of nucleoside-analogue type compounds on the functioning of the mitochondrial DNA polymerase.For detailed investigation of the yet partially understood underlying mechanisms, the availability of a versatile model system is crucial.Using a combination of molecular-biological and functional assays, combined with a quantitative analysis of mitochondrial network morphology, we conclude that anti-retroviral drugs with similar working mechanisms can be classified into distinct groups based on their effects on mitochondrial morphology and biochemistry.

View Article: PubMed Central - PubMed

Affiliation: Molecular Biology & Microbial Food Safety, Swammerdam Institute for Life Sciences (SILS), Faculty of Science (FNWI), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.

ABSTRACT
Today HIV-1 infection is recognized as a chronic disease with obligatory lifelong treatment to keep viral titers below detectable levels. The continuous intake of antiretroviral drugs however, leads to severe and even life-threatening side effects, supposedly by the deleterious impact of nucleoside-analogue type compounds on the functioning of the mitochondrial DNA polymerase. For detailed investigation of the yet partially understood underlying mechanisms, the availability of a versatile model system is crucial. We therefore set out to develop the use of Caenorhabditis elegans to study drug induced mitochondrial toxicity. Using a combination of molecular-biological and functional assays, combined with a quantitative analysis of mitochondrial network morphology, we conclude that anti-retroviral drugs with similar working mechanisms can be classified into distinct groups based on their effects on mitochondrial morphology and biochemistry. Additionally we show that mitochondrial toxicity of antiretroviral drugs cannot be exclusively attributed to interference with the mitochondrial DNA polymerase.

No MeSH data available.


Related in: MedlinePlus

Recovery of mtDNA after cessation of exposure.Worms are exposed to FLT (200 μM) from D1 of adulthood onwards for 72hrs after which they are transferred to plates without FLT. This results in a recovery of mtDNA. Error bars show the 95% C.I. (df = 16). C = untreated worms, T = #hr after transfer, 4d = 4days of continuous exposure. Significance was determined using a two-tailed student’s T test assuming unequal variances. ***P-value <0.001 compared to unexposed animals. ns: not significant compared to unexposed animals.
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pone.0126220.g002: Recovery of mtDNA after cessation of exposure.Worms are exposed to FLT (200 μM) from D1 of adulthood onwards for 72hrs after which they are transferred to plates without FLT. This results in a recovery of mtDNA. Error bars show the 95% C.I. (df = 16). C = untreated worms, T = #hr after transfer, 4d = 4days of continuous exposure. Significance was determined using a two-tailed student’s T test assuming unequal variances. ***P-value <0.001 compared to unexposed animals. ns: not significant compared to unexposed animals.

Mentions: In clinical practice the mitotoxic effects of NRTIs on patients can mostly be reversed if the treatment is interrupted [34]. To examine whether the mtDNA lowering effect of FLT is also reversible in C. elegans we performed an experiment in which adult nematodes were first exposed to 200μM FLT for 72 hrs to be certain that the maximum effect was obtained, after which the worms were transferred to a fresh plate without FLT. Adult worms were exposed to avoid any effects on the development of the worms that might influence the results. Samples were taken after 1, 2, 3, 5 and 6 hours after transfer and analyzed for mtDNA content. The results depicted in Fig 2 clearly demonstrate that FLT induced mtDNA depletion is reversible. The first two hours after transfer there is no significant recovery of mtDNA levels. Surprisingly, after three hours the mtDNA level is significantly elevated compared to pre-exposure levels. After 5 and 6 hours the amount of mtDNA gradually declines to normal levels. This effect suggests that during exposure to NRTIs, the mitochondria try to compensate for loss of mtDNA.


Caenorhabditis elegans as a Model System for Studying Drug Induced Mitochondrial Toxicity.

de Boer R, Smith RL, De Vos WH, Manders EM, Brul S, van der Spek H - PLoS ONE (2015)

Recovery of mtDNA after cessation of exposure.Worms are exposed to FLT (200 μM) from D1 of adulthood onwards for 72hrs after which they are transferred to plates without FLT. This results in a recovery of mtDNA. Error bars show the 95% C.I. (df = 16). C = untreated worms, T = #hr after transfer, 4d = 4days of continuous exposure. Significance was determined using a two-tailed student’s T test assuming unequal variances. ***P-value <0.001 compared to unexposed animals. ns: not significant compared to unexposed animals.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4430419&req=5

pone.0126220.g002: Recovery of mtDNA after cessation of exposure.Worms are exposed to FLT (200 μM) from D1 of adulthood onwards for 72hrs after which they are transferred to plates without FLT. This results in a recovery of mtDNA. Error bars show the 95% C.I. (df = 16). C = untreated worms, T = #hr after transfer, 4d = 4days of continuous exposure. Significance was determined using a two-tailed student’s T test assuming unequal variances. ***P-value <0.001 compared to unexposed animals. ns: not significant compared to unexposed animals.
Mentions: In clinical practice the mitotoxic effects of NRTIs on patients can mostly be reversed if the treatment is interrupted [34]. To examine whether the mtDNA lowering effect of FLT is also reversible in C. elegans we performed an experiment in which adult nematodes were first exposed to 200μM FLT for 72 hrs to be certain that the maximum effect was obtained, after which the worms were transferred to a fresh plate without FLT. Adult worms were exposed to avoid any effects on the development of the worms that might influence the results. Samples were taken after 1, 2, 3, 5 and 6 hours after transfer and analyzed for mtDNA content. The results depicted in Fig 2 clearly demonstrate that FLT induced mtDNA depletion is reversible. The first two hours after transfer there is no significant recovery of mtDNA levels. Surprisingly, after three hours the mtDNA level is significantly elevated compared to pre-exposure levels. After 5 and 6 hours the amount of mtDNA gradually declines to normal levels. This effect suggests that during exposure to NRTIs, the mitochondria try to compensate for loss of mtDNA.

Bottom Line: The continuous intake of antiretroviral drugs however, leads to severe and even life-threatening side effects, supposedly by the deleterious impact of nucleoside-analogue type compounds on the functioning of the mitochondrial DNA polymerase.For detailed investigation of the yet partially understood underlying mechanisms, the availability of a versatile model system is crucial.Using a combination of molecular-biological and functional assays, combined with a quantitative analysis of mitochondrial network morphology, we conclude that anti-retroviral drugs with similar working mechanisms can be classified into distinct groups based on their effects on mitochondrial morphology and biochemistry.

View Article: PubMed Central - PubMed

Affiliation: Molecular Biology & Microbial Food Safety, Swammerdam Institute for Life Sciences (SILS), Faculty of Science (FNWI), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.

ABSTRACT
Today HIV-1 infection is recognized as a chronic disease with obligatory lifelong treatment to keep viral titers below detectable levels. The continuous intake of antiretroviral drugs however, leads to severe and even life-threatening side effects, supposedly by the deleterious impact of nucleoside-analogue type compounds on the functioning of the mitochondrial DNA polymerase. For detailed investigation of the yet partially understood underlying mechanisms, the availability of a versatile model system is crucial. We therefore set out to develop the use of Caenorhabditis elegans to study drug induced mitochondrial toxicity. Using a combination of molecular-biological and functional assays, combined with a quantitative analysis of mitochondrial network morphology, we conclude that anti-retroviral drugs with similar working mechanisms can be classified into distinct groups based on their effects on mitochondrial morphology and biochemistry. Additionally we show that mitochondrial toxicity of antiretroviral drugs cannot be exclusively attributed to interference with the mitochondrial DNA polymerase.

No MeSH data available.


Related in: MedlinePlus