The effect of activation of peroxisome proliferator-activated receptor gamma (PPAR#gamma#)on human monocyte function: PPAR#gamma# ligands do not inhibit tumor necrosis factor-#alpha# release in human monocytic cell line THP-1

摘要

Peroxisome proliferator-activated receptor gamma (PPAR#gamma#) activation by its ligands reportedly inhibits monocyte function. However, because the concentrations of PPAR#gamma# ligands used in previous studies were higher than typically expected to activate PPAR#gamma#, we clarified whether PPAR#gamma# ligands influence monocyte function and cell viability of the human monocyte cell line THP-1. We determined tumor necrosis factor-alpha (TNF-#alpha#) release as a monocyte function and cell viability using 3-[4, 5-dimethylthiazol-2-y1]-2, 5-diphenyltetrazolium bromide. Both troglitazone and 15-deoxy-uiangle open~12, 14 -prostaglandin J_2 (15-d-PGJ2) seemed to inhibit phorbol ester-induced TNF-#alpha# release from THP-1 cells. On the other hand, neither pioglitazone nor rosiglitazone inhibited phorbol ester-induced TNF-#alpha# release. Because the cytotoxicity of troglitazone and 15-d-PGJ2 was significantly (#rho# < 0.05, Tukey-Kramer) stronger than that of pioglitazone and rosiglitazone, the inhibition of TNF-#alpha# release seemed to parallel the lack of cell viability. We concluded that PPAR#gamma# ligands did not directly inhibit TNF-#alpha# release in THP-1 cells.