The responses of HT22 cells to the blockade of mitochondrial complexes and potential protective effect of selenium supplementation.
Mitochondria are the major reactive oxygen species (ROS)--generating sites in mammalian cells. Blockade of complexes in the electron transport chain (ETC) increases the leakage of single electrons to O(2) and therefore increases ROS levels. Complexes I and III have been reported to be the major ROS-generating sites in mitochondria. In this study, using mouse hippocampal HT22 cells as in vitro model, we monitored the change of intracellular ROS level in response to the blockade of ETC at different complex, and measured changes of gene expression of antioxidant enzymes and phase II enzymes, also evaluated potential protective effect of selenium (Se) supplementation to the cells under this oxidative stress. In summary, our results showed that complex I was the major ROS-generating site in HT22 cells. Complex I blockade upregulated the mRNA levels of glutamylcysteine synthetase heavy and light chains, glutathione-S-transferases omega1 and alpha 2, hemoxygenase 1, thioredoxin reductase 1, and selenoprotein H. Unexpectedly, the expression of the enzymes that directly scavenge ROS decreased, including superoxide dismutases 1 and 2, glutathione peroxidase 1, and catalase. Se supplementation increased glutathione levels and glutathione peroxidase activity, indicating a potential protective role in oxidative stress caused by ETC blockade.
Department of Cell & Molecular Biology, John A Burns Medical School, University of Hawaii, Honolulu, HI 96813, USA.
Jun
J
Panee
Wanyu
W
Liu
Kyoko
K
Nakamura
Marla J
MJ
Berry
D000818:Animals; D000968:Antimycin A / Q000494:pharmacology; D000975:Antioxidants / Q000378:metabolism; D002460:Cell Line; D045222:Electron Transport Chain Complex Proteins / Q000037:antagonists & inhibitors*; D042967:Electron Transport Complex I / Q000037:antagonists & inhibitors; D042963:Electron Transport Complex II / Q000037:antagonists & inhibitors; D014450:Electron Transport Complex III / Q000037:antagonists & inhibitors; D015870:Gene Expression / Q000187:drug effects; D008314:Malonates / Q000494:pharmacology; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D011090:Polyenes / Q000494:pharmacology; D012402:Rotenone / Q000494:pharmacology; D012643:Selenium / Q000494:pharmacology*; D013481:Superoxides / Q000378:metabolism*
D000975:Antioxidants; D045222:Electron Transport Chain Complex Proteins; D008314:Malonates; D011090:Polyenes; D012402:Rotenone; D013481:Superoxides; D000968:Antimycin A; C041573:stigmatellin; C030290:malonic acid; D042963:Electron Transport Complex II; D042967:Electron Transport Complex I; D014450:Electron Transport Complex III; D012643:Selenium