Arachidonic acid metabolism in purified human lung mast cells
Peters, S.P.; MacGlashan, D.W.; Schulman, E.S.; Schleimer, R.P.; Hayes, E.C.; Rokach, J.; Adkinson, N.F.; Lichtenstein, L.M.
Journal of Immunology 132(4): 1972-1979
1984
ISSN/ISBN: 0022-1767 PMID: 6199420 Document Number: 231868
Arachidonic acid metabolism has been explored in preparations of purified human lung mast cells prelabeled with arachidonic acid (AA). Cells were of 83 to > 96% purity, and each experiment was performed with 4-6 different preparations of mast cells. After overnight culture of the purified cells in the presence of 3H-AA, followed by extensive washing in buffer, mast cell uptake of labeled AA was 61.4 .+-. 14.8 pmol/106 cells with 21 .+-. 2.4% of the label in phospholipids, 73 .+-. 2.1% in neutral lipids, and 3.6 .+-. 0.8% as free AA. Analysis of the distribution of radioactivity in phospholipid classes revealed 51.4 .+-. 5.5% of the label in phosphatidylcholine, 14.5 .+-. 1.6% in phosphatidylinositol, 12.0 .+-. 3.0% in phosphatidylethanolamine and 9.1 .+-. 2.4% in sphingomyelin, with the rest in other phospholipid classes. Challenge of these cells with an optimal concentration of anti-IgE led to the release of 20 .+-. 4.0% of cellular histamine and to a reduction in labeled phosphatidylcholine and phosphatidylinositol to 75.5 .+-. 8.8% and 84.2 .+-. 4.5% of the control levels, respectively, (P < 0.05); anti-IgE challenge produced no statistically significant change in the quantities of other labeled phospholipids. Activation of human lung mast cells with anti-IgE led to the release of 3.4 .+-. 1.3% of the cellular 3H as AA and AA metabolites (1.5 .+-. 0.6% as unmetabolized AA) in conjunction with 16 .+-. 4.3% of the cellular histamine. Although activation of human lung mast cells with ionophore A23187 2.3 .+-. 2.1%, 13 .+-. 8.1%. Activation of purified preparations of human lung mast cells with anti-IgE apparently leads to phospholipid turnover (phosphatidylcholine and phosphatidylinositol), and to the release of AA metabolites from both the cyclooxygenase (prostaglandin D2) and lipoxygenase (leukotriene C, leukotriene B isomers and 5HETE) pathways. Although challenge with anti-IgE and ionophore A23187 resulted in histamine release that was markedly different, the 2 stimuli led to the release of similar quantities and types of AA metabolites. The procedures should be useful in exploring biochemical and pharmacologic aspects of AA metabolism in purified human lung mast cells.