Limited Applicability of GW9662 to Elucidate PPARγ-Mediated Fatty Acid Effects in Primary Human T-Helper Cells

Abstract EN

Synthetic antagonists of the nuclear receptor PPARγ such as GW9662 are widely used to elucidate receptor-mediated ligand effects.

In addition and complementary to recent work, we examined whether GW9662 is suitable to serve for mechanistic investigation in T-helper cells.

Human peripheral blood mononuclear cells (PBMC) were preincubated with increasing concentrations of GW9662 (0, 0.4, 2, and 10 μmol/L) 30 min before adding the c9,t11-isomer of conjugated linoleic acid (c9,t11-CLA) as representative of PPARγ-activating fatty acids with immunomodulatory properties.

Corresponding cultures were incubated with GW9662 in the absence of the fatty acid.

After 19 h, cells were mitogen stimulated for further 5 h.

Subsequently, intracellular IL-2 was measured in CD3+CD4+ lymphocytes by means of flow cytometry.

100 μmol/L c9,t11-CLA reduced the number of T-helper cells expressing IL-2 by 68%.

GW9662 failed to abrogate this fatty acid effect, likely due to the fact that the compound exerted an own inhibitory effect on IL-2 production.

Moreover, GW9662 dose-dependently induced cell death in human leukocytes.

These results suggest that application of GW9662 is not conducive in this experimental setting.