Nitric oxide activates the glucose-dependent mobilization of arachidonic acid in a macrophage-like cell line (RAW 264.7) that is largely mediated by calcium-independent phospholipase A2.
Herein, we demonstrate that nitric oxide is a potent (> 20% release) and highly selective inducer of [3H]arachidonic acid mobilization in the macrophage-like cell line RAW 264.7. Treatment of RAW 264.7 cells with (E)-6-(bromomethylene)-3-(1-naphthalenyl)-2H-tetrahydropyran-2-one resulted in the inhibition of the large majority (86%) of nitric oxide-induced [3H]arachidonic acid release into the medium (IC50 < 0.5 microM) and the concomitant inhibition of in vitro measurable calcium-independent phospholipase A2 activity (92% inhibition) without demonstrable effects on calcium-dependent phospholipase A2 activity. Since nitric oxide is a potent stimulator of glycolysis (and therefore glycolytically derived ATP) and since cytosolic calcium-independent phospholipase A2 exists as a catalytic complex comprised of ATP-modulated phosphofructokinase-like regulatory polypeptides and a catalytic subunit, we examined the role of glucose in facilitating nitric oxide-mediated arachidonic acid release. Nitric oxide-induced release of [3H]arachidonic acid possessed an obligatory requirement for glucose, was highly correlated with the concentration of glucose in the medium, and was dependent on the metabolism of glucose. Thus, [3H]arachidonic acid release is coupled to cellular glucose metabolism through alterations in the activity of calcium-independent phospholipase A2. Collectively, these results identify a unifying metabolic paradigm in which the generation of lipid second messengers is coordinately linked to the signalstimulated acceleration of glycolytic flux, thereby facilitating integrated metabolic responses to cellular stimuli.
Gross
R W
RW
Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Rudolph
A E
AE
Wang
J
J
Sommers
C D
CD
Wolf
M J
MJ
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D002460:Cell Line; D004533:Egtazic Acid / Q000494:pharmacology; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D009281:Naphthalenes / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology*; D010741:Phospholipases A / Q000037:antagonists & inhibitors / Q000378:metabolism*; D054467:Phospholipases A2; D010743:Phospholipids / Q000378:metabolism; D011753:Pyrones / Q000494:pharmacology; D015290:Second Messenger Systems; D014316:Tritium; D015054:Zymosan / Q000494:pharmacology
D008070:Lipopolysaccharides; D009281:Naphthalenes; D010743:Phospholipids; D011753:Pyrones; D014316:Tritium; D009599:Nitroprusside; D016718:Arachidonic Acid; D009569:Nitric Oxide; D004533:Egtazic Acid; C068314:6-(bromomethylene)tetrahydro-3-(1-naphthaleneyl)-2H-pyran-2-one; D015054:Zymosan; D010741:Phospholipases A; D054467:Phospholipases A2; D002118:Calcium