Effect of peroxisome proliferator-activated receptor gamma on thromboxane A₂ and prostaglandin E₂ production in macrophage cell lines

We studied the effect of peroxisome proliferator-activated receptor γ (PPARγ) activation on thromboxane A₂(TXA₂) and prostaglandin E₂(PGE₂) production in monocyte/macrophage cell lines. In present experiment, we used human peripheral blood monocyte (PBMC), monocyte-cell line THP-1 and mouse macrophage-like cell line RAW264.7. The expression of PPARγ is reported in PBMC and THP-1. Synthetic PPARγ ligands (troglitazone or BRL49653) inhibited TXA₂ production and enhanced PGE₂ production of PBMC and THP-1. When treated with 0.5-10 μM of troglitazone, there were no significant changes of TXA₂ and PGE₂ production of RAW264.7 cells, which express very low levels of PPARγ. When RAW264.7 cells was transfected with PPARγ expression plasmid and treated with troglitazone, PPARγ was activated in a dose-dependent manner. In PPARγ-transfected RAW264.7, TXA₂ production was decreased and PGE₂ production was increased by troglitazone treatment. But it needs high concentration of troglitazone (10 μM) for increasing PGE₂ production. These results suggest that PPARγ may have negative effect on TXA₂ production, and also have slightly positive effect on PGE₂ production of macrophage.