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Mitochondrial complex I inhibitor rotenone induces apoptosis through enhancing mitochondrial reactive oxygen species
Nianyu Li1, Kathy Ragheb, Gretchen Lawler
1Purdue University Cytometry Laboratories, Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
Abstract:
Inhibition of mitochondrial respiratory chain complex I by rotenone had been found to induce cell death in a variety of cells. However, the mechanism is still elusive. Because reactive oxygen species (ROS) play an important role in apoptosis and inhibition of mitochondrial respiratory chain complex I by rotenone was thought to be able to elevate mitochondrial ROS production, we investigated the relationship between rotenone-induced apoptosis and mitochondrial reactive oxygen species. Rotenone was able to induce mitochondrial complex I substrate-supported mitochondrial ROS production both in isolated mitochondria from HL-60 cells as well as in cultured cells. Rotenone-induced apoptosis was confirmed by DNA fragmentation, cytochrome c release, and caspase 3 activity. A quantitative correlation between rotenone-induced apoptosis and rotenone-induced mitochondrial ROS production was identified. Rotenone-induced apoptosis was inhibited by treatment with antioxidants (glutathione, N-acetylcysteine, and vitamin C). The role of rotenone-induced mitochondrial ROS in apoptosis was also confirmed by the finding that HT1080 cells overexpressing magnesium superoxide dismutase were more resistant to rotenone-induced apoptosis than control cells. These results suggest that rotenone is able to induce apoptosis via enhancing the amount of mitochondrial reactive oxygen species production.
Insights
Rotenone induces apoptosis, a form of programmed cell death, by increasing mitochondrial reactive oxygen species (ROS). Antioxidants and superoxide dismutase protect cells, confirming ROS
Area of Science:
- Biochemistry
- Cell Biology
- Toxicology
Background:
- Rotenone inhibits mitochondrial respiratory chain complex I, leading to cell death.
- The precise mechanism of rotenone-induced cell death, particularly the role of reactive oxygen species (ROS), remains unclear.
Purpose of the Study:
- To investigate the relationship between rotenone-induced apoptosis and mitochondrial ROS production.
- To elucidate the role of mitochondrial ROS in rotenone-induced cell death.
Main Methods:
- Assessing mitochondrial ROS production in isolated HL-60 cell mitochondria and cultured cells treated with rotenone.
- Confirming apoptosis using DNA fragmentation, cytochrome c release, and caspase 3 activity assays.
- Evaluating the effects of antioxidants (glutathione, N-acetylcysteine, vitamin C) and magnesium superoxide dismutase overexpression on rotenone-induced apoptosis.
Main Results:
- Rotenone treatment significantly increased mitochondrial ROS production.
- Rotenone induced apoptosis, evidenced by DNA fragmentation, cytochrome c release, and caspase 3 activation.
- Apoptosis was dose-dependently inhibited by antioxidants.
- HT1080 cells overexpressing magnesium superoxide dismutase showed increased resistance to rotenone-induced apoptosis.
Conclusions:
- Rotenone induces apoptosis primarily by enhancing mitochondrial ROS production.
- Mitochondrial ROS play a critical role in mediating rotenone-induced cell death.
- Targeting ROS may offer a therapeutic strategy against rotenone toxicity.