On the importance of plasmalogen status in stimulated arachidonic acid release in the macrophage cell line RAW 264.7.
We examined the dependence of stimulated arachidonic acid release on plasmalogens using the murine, macrophage cell line 264.7 and two plasmalogen-deficient variants, RAW.12 and RAW.108. All three strains responded to unopsinized zymosan to release arachidonic acid from phospholipid stores. Arachidonic acid release appeared to be dependent on calcium-independent phospholipase A(2) activation (iPLA(2)); bromoenol lactone, a specific inhibitor of calcium-independent iPLA(2), blocked arachidonic acid release with an IC(50) of approximately 2 x 10(-7)M. Propanolol, an inhibitor of phosphatidate phosphatase, and RHC-80267, an inhibitor of diglyceride lipase, had no effect on arachidonic acid release. Arachidonic acid release in the variants displayed similar magnitude, kinetics of response and sensitivity to the inhibitors when compared to the parent strain. Arachidonic acid was released from all major phospholipid head group classes with the exception of sphingomyelin. In wild-type cells, arachidonic acid released from the ethanolamine phospholipids was primarily from the plasmalogen form. However, in the plasmalogen-deficient cells release from the diacyl species, phosphatidylethanolamine, was increased to compensate. Restoration of plasmalogens by supplementation of the growth medium with the bypass compounds sn-1-hexadecylglycerol and sn-1-alkenylglycerol had no effect on arachidonic acid release. In summary, plasmalogen status appears to have no influence on the zymosan A stimulated release of arachidonic acid from the RAW 264.7 cell line.
Gaposchkin
Daniel P
DP
Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, Massachusetts 02118, USA.
Farber
Harrison W
HW
Zoeller
Raphael A
RA
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D002460:Cell Line; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D009281:Naphthalenes / Q000494:pharmacology; D064801:Phospholipase A2 Inhibitors; D010955:Plasmalogens / Q000494:pharmacology*; D011753:Pyrones / Q000494:pharmacology; D015054:Zymosan / Q000494:pharmacology
D009281:Naphthalenes; D064801:Phospholipase A2 Inhibitors; D010955:Plasmalogens; D011753:Pyrones; D016718:Arachidonic Acid; C068314:6-(bromomethylene)tetrahydro-3-(1-naphthaleneyl)-2H-pyran-2-one; D015054:Zymosan