Stimulation of mitochondrial gene expression and proliferation of mitochondria following impairment of cellular energy transfer by inhibition of the phosphocreatine circuit in rat hearts

Effects of hydrogen peroxide on mitochondrial gene expression of intestinal epithelial cells

AIM: To study the effects of hydrogen peroxide on mitochondrial gene expression of intestinal epithelial cells in in vitro model of hydrogen peroxide-stimulated SW-480 cells.

METHODS: RNA of hydrogen peroxide-induced SW-480 cells was isolated, and reverse-transcriptional polymerase chain reaction was performed to study gene expression of ATPase subunit 6, ATPase subunit 8, cytochrome c oxidase subunit I (COI), cytochrome coxidase subuit II (COII) and cytochrome c oxidase subunit III (COIII). Mitochondria were isolated and activities of mitochondrial cytochrome c oxidase and ATPase were also measured simultaneously.

RESULTS: Hydrogen peroxide led to differential expression of mitochondrial genes with some genes up-regulated or down-regulated in a dose dependent manner. Differences were very obvious in expressions of mitochondrial genes of cells treated with hydrogen peroxide in a concentration of 400 μmol/L or 4 mmol/L. In general, differential expression of mitochondrial genes was characterized by up-regulation of mitochondrial genes in the concentration of 400 μmol/L and down-regulation in the concentration of 4 mmol/L. In consistence with changes in mitochondrial gene expressions, hydrogen peroxide resulted in decreased activities of cytochrome c oxidase and ATPase.

CONCLUSION: The differential expression of mitochondrial genes encoding cytochrome c oxidase and ATPase is involved in apoptosis of intestinal epithelial cells by affecting activities of cytochorme c oxidase and ATPase.