Nrf2 regulates antioxidant gene expression evoked by oxidized phospholipids in endothelial cells and murine arteries in vivo.
Besides their well-characterized proinflammatory and proatherogenic effects, oxidized phospholipids, such as oxPAPC (oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphocholine) have been shown to have beneficial responses in vascular cells via induction of antioxidant enzymes such as heme oxygenase-1. We therefore hypothesized that oxPAPC could evoke a general cytoprotective response via activation of antioxidative transcription factor Nrf2. Here, we show that oxPAPC increases nuclear accumulation of Nrf2. Using the small interfering RNA approach, we demonstrate that Nrf2 is critical in mediating the induction of glutamate-cysteine ligase modifier subunit (GCLM) and NAD(P)H quinone oxidoreductase-1 (NQO1) by oxPAPC in human endothelial cells, whereas the contribution to the induction of heme oxygenase-1 was less significant. The induction of GCLM and NQO1 was attenuated by reduction of electrophilic groups with sodium borohydrate, as well as treatment with thiol antioxidant N-acetylcysteine, suggesting that the thiol reactivity of oxPAPC is largely mediating its effect on Nrf2-responsive genes. Moreover, we show that oxidized phospholipid having a highly electrophilic isoprostane ring in its sn-2 position is a potent inducer of Nrf2 target genes. Finally, we demonstrate that the oxPAPC-inducible expression of heme oxygenase-1, GCLM, and NQO1 is lower in Nrf2-null than wild-type mouse carotid arteries in vivo. We suggest that the activation of Nrf2 by oxidized phospholipids provides a mechanism by which their deleterious effects are limited in the vasculature.
Jyrkkänen
Henna-Kaisa
HK
Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute, University of Kuopio, Finland.
Kansanen
Emilia
E
Inkala
Matias
M
Kivelä
Annukka M
AM
Hurttila
Hanna
H
Heinonen
Suvi E
SE
Goldsteins
Gundars
G
Jauhiainen
Suvi
S
Tiainen
Satu
S
Makkonen
Harri
H
Oskolkova
Olga
O
Afonyushkin
Taras
T
Koistinaho
Jari
J
Yamamoto
Masayuki
M
Bochkov
Valery N
VN
Ylä-Herttuala
Seppo
S
Levonen
Anna-Liisa
AL
D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000502:physiology; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002339:Carotid Arteries / Q000166:cytology / Q000201:enzymology*; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects* / Q000502:physiology; D005721:Glutamate-Cysteine Ligase / Q000096:biosynthesis / Q000235:genetics; D051547:Heme Oxygenase-1 / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D008817:Mice, Mutant Strains; D016660:NAD(P)H Dehydrogenase (Quinone); D009252:NADPH Dehydrogenase / Q000096:biosynthesis / Q000235:genetics; D051267:NF-E2-Related Factor 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D010713:Phosphatidylcholines / Q000378:metabolism / Q000493:pharmacokinetics*; D034741:RNA, Small Interfering / Q000235:genetics
D000975:Antioxidants; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; D010713:Phosphatidylcholines; D034741:RNA, Small Interfering; C472349:oxidized-L-alpha-1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine; D051547:Heme Oxygenase-1; D016660:NAD(P)H Dehydrogenase (Quinone); C491732:Nqo1 protein, mouse; D009252:NADPH Dehydrogenase; D005721:Glutamate-Cysteine Ligase