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The effect of ethidium bromide and chloramphenicol on mitochondrial biogenesis in primary human fibroblasts
Li-Pin Kao1, Dmitry Ovchinnikov, Ernst Wolvetang
1Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia.
Abstract:
The expression of mitochondrial components is controlled by an intricate interplay between nuclear transcription factors and retrograde signaling from mitochondria. The role of mitochondrial DNA (mtDNA) and mtDNA-encoded proteins in mitochondrial biogenesis is, however, poorly understood and thus far has mainly been studied in transformed cell lines. We treated primary human fibroblasts with ethidium bromide (EtBr) or chloramphenicol for six weeks to inhibit mtDNA replication or mitochondrial protein synthesis, respectively, and investigated how the cells recovered from these insults two weeks after removal of the drugs. Although cellular growth and mitochondrial gene expression were severely impaired after both inhibitor treatments we observed marked differences in mitochondrial structure,membrane potential, glycolysis, gene expression, and redox status between fibroblasts treated with EtBr and chloramphenicol. Following removal of the drugs we further detected clear differences in expression of both mtDNA-encoded genes and nuclear transcription factors that control mitochondrial biogenesis, suggesting that the cells possess different compensatory mechanisms to recover from drug-induced mitochondrial dysfunction. Our data reveal new aspects of the interplay between mitochondrial retrograde signaling and the expression of nuclear regulators of mitochondrial biogenesis, a process with direct relevance to mitochondrial diseases and chloramphenicol toxicity in humans.
Insights
Primary human cells treated with drugs showed distinct recovery patterns affecting mitochondrial function and gene expression. This reveals unique cellular repair mechanisms for mitochondrial dysfunction relevant to human diseases.
Area of Science:
- Cell Biology
- Biochemistry
- Genetics
Background:
- Mitochondrial component expression involves nuclear factors and mitochondrial retrograde signaling.
- The role of mitochondrial DNA (mtDNA) and its encoded proteins in mitochondrial biogenesis is not well understood, with limited research in primary cells.
Purpose of the Study:
- Investigate cellular recovery from mitochondrial dysfunction induced by inhibiting mtDNA replication or protein synthesis.
- Explore differences in mitochondrial structure, function, and gene expression during recovery.
- Elucidate the interplay between mitochondrial retrograde signaling and nuclear regulators of mitochondrial biogenesis.
Main Methods:
- Primary human fibroblasts were treated with ethidium bromide (EtBr) or chloramphenicol to inhibit mtDNA replication or mitochondrial protein synthesis, respectively.
- Cells were analyzed two weeks after drug removal to assess recovery.
- Evaluated cellular growth, mitochondrial gene expression, mitochondrial structure, membrane potential, glycolysis, and redox status.
Main Results:
- Both EtBr and chloramphenicol treatments severely impaired cellular growth and mitochondrial gene expression.
- Distinct differences were observed in mitochondrial structure, membrane potential, glycolysis, gene expression, and redox status between EtBr- and chloramphenicol-treated cells post-recovery.
- Differential expression of mtDNA-encoded genes and nuclear transcription factors controlling mitochondrial biogenesis was detected, indicating varied compensatory mechanisms.
Conclusions:
- Cells exhibit distinct compensatory mechanisms to recover from drug-induced mitochondrial dysfunction.
- Findings highlight the complex interplay between mitochondrial retrograde signaling and nuclear regulators of mitochondrial biogenesis.
- The study provides insights relevant to mitochondrial diseases and chloramphenicol toxicity in humans.
