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A 4-oxo-2(E)-nonenal-derived Glutathione Adduct From 15-lipoxygenase-1-mediated Oxidation of Cytosolic and Esterified Arachidonic Acid

Peijuan Zhu, Wenying Jian, Ian A Blair

Free Radic Biol Med. 2009 Oct 1;47(7):953-61.

PMID: 19576981

Abstract:

15(S)-Hydroperoxy-[5Z,8Z,11Z,13E]-eicosatetraenoic acid (15(S)-HpETE) undergoes homolytic decomposition to bifunctional electrophiles such as 4-oxo-2(E)-nonenal. 4-Oxo-2(E)-nonenal reacts with glutathione to form a thiadiazabicyclo-4-oxo-2(E)-nonenal-glutathione adduct (TOG). Therefore, this endogenous glutathione adduct can serve as a specific biomarker of lipid hydroperoxide-mediated 4-oxo-2(E)-nonenal formation. A monocyte/macrophage cell line was generated to constitutively express human 15-lipoxygenase-1. In these cells, TOG was formed from 15(S)-HpETE-derived 4-oxo-2(E)-nonenal in a nonlinear dose-dependent manner upon arachidonic acid treatment. The lipoxygenase inhibitor cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate abolished arachidonic acid-mediated TOG formation. The calcium ionophore A23187 was also used to induce the formation of 15(S)-HpETE from esterified arachidonic acid present in the membrane lipids. In the 15-lipoxygenase-1-expressing cells, the calcium ionophore A23187 significantly increased TOG levels compared with mock-transfected cells. This was due to the 15-lipoxygenase-mediated formation of 15(S)-HpETE in the forms of free fatty acid and esterified lipids, which was subsequently converted to 4-oxo-2(E)-nonenal. The increase in TOG formation was again abrogated by pretreatment with cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate. Only 8.7% 15(S)-HETE (both the free fatty acid and its esterified form in the cell membrane) was formed after ionophore A23187 stimulation compared with that formed after the addition of arachidonic acid. In contrast, the TOG levels after treatment with ionophore A23187 or arachidonic acid were comparable. Thus, it is likely that esterified 15(S)-HpETE underwent homolytic decomposition to 4-oxo-2(E)-nonenal more efficiently than the free 15(S)-HpETE that was formed in the cytosol.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP132465113 Cinnamyl-3,4-dihydroxy-α-cyanocinnamate Cinnamyl-3,4-dihydroxy-α-cyanocinnamate 132465-11-3 Price
AP70981963 15(S)-Hydroperoxy-(5Z,8Z,11Z,13E)-eicosatetraenoic acid 15(S)-Hydroperoxy-(5Z,8Z,11Z,13E)-eicosatetraenoic acid 70981-96-3 Price
IAR4242247 (E)-4-Amino-2-butenoic acid (E)-4-Amino-2-butenoic acid Price
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