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Oxidant injury of cultured cells: biochemical consequences
Abstract:
The experimental results summarized here suggest a mechanism of oxidant induced cell injury which begins with the generation of DNA strand breaks. The mechanism of the generation of these breaks is currently under investigation. The presence of DNA strand breaks activates pADPr polymerase which causes the conversion of cellular NAD to pADPr and free nicotinamide. It is likely that low levels of NAD are associated with inhibition of glycolysis and thereby contribute to the oxidant-induced fall in cell ATP. Additional factors are likely to contribute to altered cell metabolism following oxidant injury. Hyslop has shown that the Vmax of a critical enzyme of the glycolytic pathway, glyceraldehyde-3-phosphate dehydrogenase, is decreased following exposure to oxidant. Finally, it is likely that the oxidative phosphorylation functions of the mitochondrial membrane may also be perturbed by oxidant injury. The extent to which these alterations in cell metabolism occur in vivo following exposure to oxidants may be of great importance to our understanding of acute inflammatory tissue injury.
Insights
Oxidant-induced cell injury involves DNA strand breaks, activating enzymes that deplete cellular NAD and inhibit glycolysis. This leads to reduced ATP levels and altered cell metabolism, crucial for understanding inflammatory tissue damage.
Area of Science:
- Biochemistry
- Cell Biology
- Toxicology
Background:
- Oxidative stress is a key factor in cellular damage.
- Understanding the molecular mechanisms of oxidant-induced cell injury is critical.
Purpose of the Study:
- To elucidate the mechanism of oxidant-induced cell injury.
- To identify key metabolic alterations following oxidant exposure.
Main Methods:
- The study summarizes experimental results suggesting a mechanism.
- Investigated the role of DNA strand breaks and enzyme activation.
Main Results:
- DNA strand breaks trigger poly(ADP-ribose) polymerase (pADPr polymerase) activation.
- Depletion of cellular NAD inhibits glycolysis, reducing ATP levels.
- Oxidant exposure decreases glyceraldehyde-3-phosphate dehydrogenase activity and perturbs mitochondrial function.
Conclusions:
- Oxidant-induced cell injury involves a cascade of metabolic disruptions.
- These metabolic alterations are significant for understanding inflammatory tissue injury in vivo.