Regulation of intracellular pH by phospholipase A2 and protein kinase C upon neutrophil adhesion to solid substrata

• Published in: FEBS letters 1996-09, Vol.393 (1), p.117-120
• Main Authors: Galkina, S.I., Sud'ina, G.F., Margolis, L.B.
• Format: Article
• Language: English
• Subjects: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine - pharmacology; AA, arachidonic acid; Acetophenones - pharmacology; Adhesion; Albumins - metabolism; Arachidonic acid; Arachidonic Acid - pharmacology; Cell Adhesion; Cl-NBD, 7-chloro-4-nitrobenz-2-oxa-1,3-diazole; Fibronectins - metabolism; Humans; Hydrogen-Ion Concentration; Intracellular pH; LPC, lysophosphatidylcholine; Lysophosphatidylcholines - pharmacology; NEM, N-ethylmaleimide; Neutrophil; Neutrophils - metabolism; pH(i), intracellular pH; Phospholipase A2; Phospholipases A - antagonists & inhibitors; Phospholipases A - metabolism; Phospholipases A2; PKC, protein kinase C; PLA2, phospholipase A2; PLC, phospholipase C; PMA, phorbol 12-myristate 13-acetate; Protein kinase C; Protein Kinase C - antagonists & inhibitors; Protein Kinase C - metabolism; Terpenes - pharmacology; Tetradecanoylphorbol Acetate - pharmacology
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(96)00864-2

Adhesion to solid substrata has been shown to increase intracellular pH (pH(i)) of fibroblasts and of other cells (FEBS Lett. (1988) 234, 449–450; Proc. Natl. Acad. Sci. USA (1989) 86, 4525–4529; J. Biol. Chem. (1990) 265, 1327–1332; Exp. Cell Res. (1992) 200, 211–214; FEBS Lett. (1995) 374,17–20). We have found that the inhibitors of PLA2, 4-bromophenacyl bromide and manoalide, completely blocked the increase of pH(i) and spreading of neutrophils upon adhesion to solid substrata. Inhibition of phospholipase C with neomycin or removal of extracellular Ca 2+ affects neither neutrophil spreading nor their pH(i). Inhibition of PKC with H-7 or staurosporin increased pH(i). PMA, an activator of PKC, dramatically decreased pH(i) but did not impair the spreading of neutrophils. The effect of arachidonic acid, a product of PLA2 activity, on neutrophil pH(i) and spreading was similar to that of PMA. H-7, an inhibitor of PKC, partially blocked the effect of arachidonic acid (AA) on pH(i). BW755C, an inhibitor of AA metabolism by cyclooxygenase or lipoxygenase, affected neither the pH(i) nor cell spreading. We propose that the increase of pH(i) upon neutrophil adhesion is mediated by PLA2 activity, while PKC decreased pH(i). AA produced by PLA2 activates PKC, thus forming a feedback regulation of pH(i).