Hyperoxia-induced apoptosis does not require mitochondrial reactive oxygen species and is regulated by Bcl-2 proteins.

Abstract

Exposure of animals to hyperoxia results in lung injury that is characterized by apoptosis and necrosis of the alveolar epithelium and endothelium. The mechanism by which hyperoxia results in cell death, however, remains unclear. We sought to test the hypothesis that exposure to hyperoxia causes mitochondria-dependent apoptosis that requires the generation of reactive oxygen species from mitochondrial electron transport. Rat1a cells exposed to hyperoxia underwent apoptosis characterized by the release of cytochrome c, activation of caspase-9, and nuclear fragmentation that was prevented by the overexpression of Bcl-X(L.) Murine embryonic fibroblasts from bax(-/-) bak(-/-) mice were resistant to hyperoxia-induced cell death. The administration of the antioxidants manganese (III) tetrakis (4-benzoic acid) porphyrin, ebselen, and N-acetylcysteine failed to prevent cell death following exposure to hyperoxia. Human fibrosarcoma cells (HT1080) lacking mitochondrial DNA (rho(0) cells) that failed to generate reactive oxygen species during exposure to hyperoxia were not protected against cell death following exposure to hyperoxia. We conclude that exposure to hyperoxia results in apoptosis that requires Bax or Bak and can be prevented by the overexpression of Bcl-X(L). The mitochondrial generation of reactive oxygen species is not required for cell death following exposure to hyperoxia.

• Authors: G R Scott Budinger, May Tso, David S McClintock, David A Dean, Jacob I Sznajder, Navdeep S Chandel
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 277 Issue 18 Pg. 15654-60 (May 03 2002) ISSN: 0021-9258 [Print] United States
• PMID: 11877388 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Proto-Oncogene Proteins c-bcl-2
• Reactive Oxygen Species
• Antimycin A

Topics

• Animals
• Antimycin A (pharmacology)
• Apoptosis (physiology)
• Cell Line
• Cells, Cultured
• Fibrosarcoma
• Hyperoxia
• Intracellular Membranes (physiology)
• Membrane Potentials (drug effects)
• Mitochondria (physiology)
• Proto-Oncogene Proteins c-bcl-2 (metabolism)
• Rats
• Reactive Oxygen Species (metabolism)
• Tumor Cells, Cultured