FIGURE 6.

PGD₂ production and up-regulation of COX-2 expression by LAD2 cells in response to cys-LTs and the involvement of PPARγ in mediating these effects. A, dose response of cys-LT-mediated PGD₂ generation in LAD2 cells stimulated with the indicated concentrations of cys-LTs for 6 h. B, time course of PGD₂ generation by LAD2 cells stimulated for the indicated intervals with LTD₄ (500 nm) or LTE₄ (500 nm). C, real-time PCR showing relative levels of COX-2 transcript expression by LAD2 cells stimulated with 100 nm LTD₄ or LTE₄ for 2 h. Data in A–D are the mean ± S.E. from three experiments each. D, time course of COX-2 protein induction in cells stimulated with LTD₄ (100 nm) and LTE₄ (100 nm) for the indicated periods of time. Data are from a single experiment representative of the three performed. E, effect of GW9662 (10 μm, 1 h) on COX-2 protein up-regulation in response to LTD₄ and LTE₄ (100 nm for 4 h each,). Data are from a single experiment representative of three performed. F, effect of pretreatment with GW9662 (10 μm, 1h), PD98059 (50 μm, 30 min), and NS398 (10 μm, 30 min) on LTE₄-induced generation of PGD₂ (measured 6 h after stimulation) by LAD2 cells. Data depicted are the mean ± S.D. of three independent experiments. PGD₂ was quantitated with a PGD₂-MOX assay.