U-101033E (2,4-diaminopyrrolopyrimidine), a potent inhibitor of membrane lipid peroxidation as assessed by the production of 4-hydroxynonenal, malondialdehyde, and 4-hydroxynonenal--protein adducts.
4-Hydroxy-2-nonenal (4-HNE) and malondialdehyde (MDA) are major lipid peroxidation products generated by free radical attack on membranes and appear to contribute to the cytotoxic effects of oxidative stress by a mechanism involving adduct formation with cellular proteins. In the present studies, we investigated the relationship between lipid peroxidation and eventual inactivation of plasma membrane proteins using a model system consisting of purified red blood cell membranes and Fe2+/EDTA. Using this system, we also analyzed the ability of a novel antioxidant, U-101033E (2,4-diaminopyrrolopyrimidine), to inhibit lipid peroxidation and associated protein damage. Our results demonstrated that significant levels of MDA and 4-HNE are generated in this model system, and that both aldehydes are capable of cross-linking membrane proteins. In addition, we used a monoclonal antibody to demonstrate the presence of 4-HNE-protein adducts in this system. The generation of 4-HNE-protein adducts closely paralleled the time course of lipid peroxidation and membrane protein cross-linking, suggesting that 4-HNE may contribute to membrane protein cross-linking. Analysis of U-101033E in this system showed that this antioxidant inhibited lipid peroxidation, prevented the appearance of 4-HNE-protein adducts, and strongly reduced membrane protein cross-linking, with an EC50 of 0.5 microM. We also show that these antioxidant effects were not due to the scavenging of superoxide anion. Thus, these studies demonstrate the potential usefulness of U-101033E for treating certain disease processes where lipid peroxidation plays a role in disease pathogenesis.
Rohn
T T
TT
Department of Veterinary Molecular Biology, Montana State University, Bozeman 59717, USA.
Nelson
L K
LK
Waeg
G
G
Quinn
M T
MT
D000447:Aldehydes / Q000737:chemistry / Q000378:metabolism*; D000918:Antibody Specificity; D000975:Antioxidants / Q000494:pharmacology*; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects*; D008315:Malondialdehyde / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry*; D011743:Pyrimidines / Q000494:pharmacology*; D011759:Pyrrolidines / Q000494:pharmacology*
D000447:Aldehydes; D000975:Antioxidants; D008563:Membrane Lipids; D008565:Membrane Proteins; D011743:Pyrimidines; D011759:Pyrrolidines; C101923:U 101033E; D008315:Malondialdehyde; D007501:Iron; C027576:4-hydroxy-2-nonenal