Douarre C, Sourbier C, Dalla Rosa I, Brata Das B, Redon CE, Zhang H, Neckers L, Pommier Y. Mitochondrial topoisomerase I is critical for mitochondrial integrity and cellular energy metabolism.
PLoS One 2012;
7:e41094. [PMID:
22911747 PMCID:
PMC3401127 DOI:
10.1371/journal.pone.0041094]
[Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Accepted: 06/18/2012] [Indexed: 02/04/2023] Open
Abstract
Background
Mitochondria contain their own DNA genome (mtDNA), as well as specific DNA replication and protein synthesis machineries. Relaxation of the circular, double-stranded mtDNA relies on the presence of topoisomerase activity. Three different topoisomerases have been identified in mitochondria: Top1mt, Top3α and a truncated form of Top2β.
Methodology/Principal Findings
The present study shows the importance of Top1mt in mitochondrial homeostasis. Here we show that Top1mt−/− murine embryonic fibroblasts (MEF) exhibit dysfunctional mitochondrial respiration, which leads decreased ATP production and compensation by increased glycolysis and fatty acid oxidation. ROS production in Top1mt−/− MEF cells is involved in nuclear DNA damage and induction of autophagy. Lack of Top1mt also triggers oxidative stress and DNA damage associated with lipid peroxidation and mitophagy in Top1mt−/− mice.
Conclusion/Significance
Together, our data implicate Top1mt for mitochondrial integrity and energy metabolism. The compensation mechanism described here contributes to the survival of Top1mt−/− cells and mice despite alterations of mitochondrial functions and metabolism. Therefore, this study supports a novel model for cellular adaptation to mitochondrial damage.
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