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A team led by Dr. Marcus Conrad, research group leader at the Institute of Developmental Genetics (IDG) at Helmholtz Zentrum München, showed for the first time why selenium is a limiting factor for mammals. The scientists have been investigating for years the processes of a novel type of cell death, known as ferroptosis. The enzyme GPX4, which normally contains selenium in the form of the amino acid selenocysteine, plays an important role.
In order to better understand the role of GPX4 in this death process, they established and studied mouse models in which the enzyme was modified.In one of these models, they observed that mice with a replacement of selenium to sulfur in GPX4 did not survive for longer than three weeks due to neurological complications.
In their search for the underlying reasons, the researchers identified a distinct subpopulation of specialized neurons in the brain, which were absent when selenium-containing GPX4 was lacking.
Furthermore, the scientists were able to show that ferroptosis is triggered by oxidative stress, which is known to occur for instance during high metabolic activity of cells and high neuronal activity.
Selenium-containing GPX4 protects these specialized neurons from oxidative stress and from ferroptotic cell death. Selenoenzymes are essential in some organisms, including mammals, whereas they are dispensable in other organisms, such as fungi and higher plants.
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