Synergic effects of mycoplasmal lipopeptides and extracellular ATP on activation of macrophages

Mycoplasmal lipopeptides S-(2,3-bispalmitoyloxypropyl)-CGDPKHSPKSF and S-(2,3-bispalmitoyloxypropyl)-CGNNDESNISFKEK activated a monocytic cell line, THP-1 cells, to produce tumor necrosis factor alpha. The activity of the lipopeptides was augmented by ATP in a dose-dependent manner. In addition, the level of expression of mRNAs for tumor necrosis factor alpha and interleukin-1β, -6, and -8 was also upregulated by the lipopeptides and/or extracellular ATP, but that of interleukin-10 was not. The P2X purinergic receptor antagonists pyridoxal phosphate 6-azophenyl 2′,4′-disulfonic acid and periodate-oxidized ATP suppressed the activity of ATP to augment the activation of THP-1 cells by the lipopeptides, suggesting that P2X receptors play important roles in the activity of ATP. The nuclear factor κB inhibitor dexamethasone also suppressed the activity, suggesting that the activity of ATP is dependent upon the nuclear factor κB. Thus, these results suggest that the interaction of extracellular ATP with the P2X receptors is attributed to the activity of ATP to augment the activation of THP-1 cells by mycoplasmal lipopeptides.