Oxidative stress: Mechanism of cell death...( This press release is available in...)

This press release is available in German.

Life processes in cells require a reducing environment that needs to be sustained with the help of a large number of antioxidative enzymes. This may sound abstract and incomprehensible, but everyone knows the phenomenon that a piece of cut apple or a piece of cut meat changes colour quickly and deteriorates, because the oxygen in the air produces chemical reactions in the tissues (oxidation of biomolecules).

If the equilibrium in the organism moves towards oxidative processes, then this is known as oxidative stress. Oxidative stress, for instance, is associated with the aging of body cells. Furthermore, a strong accumulation of reactive oxygen species (ROS) along with drops in cellular concentrations of glutathione, (GSH), the major antioxidant produced by the body, is well known as a common cause of acute and chronic degenerative diseases, such as, arteriosclerosis, diabetes, stroke, Alzheimer's and Parkinson's diseases.

"To investigate the molecular function of the cellular reducing agent GSH in the metabolic pathway of cell death triggered by oxidative stress, mice and cells were generated that specifically lack glutathione peroxidase 4 (GPx4), which is emerging as one of the most important GSH dependent enzymes", explains Marcus Conrad. The induced inactivation of GPx4 caused massive oxidation of lipids and eventually cell death. A similar phenotype could be observed when intracellular GSH was removed from wild-type cells by a chemical inhibitor of GSH biosynthesis.

Interestingly enough, this cell death could be completely prevented by Vitamin E, but not by water-soluble antioxidants. Since the oxidation of fatty acids in this cell death pathway, was of paramount importance, multiple studies were performed to describe, in greater detail, the source and nature of lipid peroxides.

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