Mercapturate metabolism of 4-hydroxy-2-nonenal in rat and human cerebrum.
4-Hydroxy-2-nonenal (HNE), a potent toxin formed in the brain from oxidation of polyunsaturated fatty acids, is increased in Alzheimer disease (AD), where it is a proposed effector of amyloid beta peptide-mediated neurotoxicity. Detoxification of HNE via the mercapturic acid pathway (MAP) is the primary means by which other organs, such as liver, limit its toxic effects. Here we examined the distribution and activity of MAP detoxification for HNE in cerebrum. Our results showed that rat cerebral cortex and especially synaptosomes were less well equipped to detoxify HNE via the MAP than liver. Glutathione transferases (GSTs) catalyze the committed step in the MAP; GST-mu and GST-pi, but not OST-alpha, were detected in neurons and astrocytes in cerebrum from AD patients and controls. MAP activity in frontal cortex of AD patients was modestly but significantly increased compared to controls. These data suggest that lipid peroxidation may present a greater toxic burden to cerebrum than to other organs, and that a component of response to injury in late stage AD is a slight increase in MAP activity.
Sidell
Kathrin R
KR
Department of Pathology and the Center for Molecular Toxicology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Montine
Kathleen S
KS
Picklo
Matrhew J
MJ
Olsen
Sandra J
SJ
Amarnath
Ventkataraman
V
Montine
Thomas J
TJ
D000111:Acetylcysteine / Q000378:metabolism*; D000447:Aldehydes / Q000378:metabolism*; D000544:Alzheimer Disease / Q000378:metabolism* / Q000503:physiopathology; D016229:Amyloid beta-Peptides / Q000378:metabolism; D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism* / Q000503:physiopathology; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D015227:Lipid Peroxidation / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D017729:Presynaptic Terminals / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013574:Synaptosomes / Q000378:metabolism
D000447:Aldehydes; D016229:Amyloid beta-Peptides; D005231:Fatty Acids, Unsaturated; D005982:Glutathione Transferase; C027576:4-hydroxy-2-nonenal; D000111:Acetylcysteine