Figure 3.

Leptin-induced lipid body-driven LTC4 synthesis depends on PI3K activation. In (A) human eosinophils were pretreated with PI3K inhibitors (1 μM wortmannin or 10 μM LY294002) or a PKC inhibitor (calphostin C; 1 mM) 30 min before stimulation with hr leptin (50 nM) for 1 h. (B) shows confocal images overlays of intracellular EicosaCell immuno-detection of newly formed LTC₄ (green) and DAPI stained nuclei (blue) within hr leptin-stimulated (upper image) or LY294002-treated hr leptin-stimulated (bottom image) human eosinophils. In (C) mouse eosinophils were pretreated with PI3K inhibitor LY294002 (10 μM) for 30 min before stimulation with mr leptin (50 nM) for 1 h. Lipid body count was evaluated in osmium-stained cells and LTC₄ production in cell-free supernatants by EIA kits. Values are expressed as the mean ± SEM of at least three distinct donors or three different mouse bone marrow cultures. + p < 0.05 compared with control. ^*p < 0.05 compared with leptin-stimulated eosinophils.