The role of heme oxygenase-1 in down regulation of PGE2 production by taurine chloramine and taurine bromamine in J774.2 macrophages.

Taurine chloramine (TauCl) and taurine bromamine (TauBr), products of myeloperoxidase halide system, exert anti-inflammatory properties. TauCl was demonstrated to inhibit the production of a variety of pro-inflammatory mediators including cyclooxygenase-2 (COX-2) dependent production of prostaglandin E(2) (PGE(2)). Recently we have demonstrated that both major leukocyte haloamines, TauCl and TauBr, induced expression of HO-1 in non-activated and LPS-activated J774.2 macrophages. In this study, we have shown that TauCl and TauBr, at non-cytotoxic concentrations, inhibited the production of (PGE(2)) without altering the expression of COX-2 protein, in LPS/IFN-gamma stimulated J774.2 cells. The inhibitory effect of TauCl and TauBr was reversed by chromium III mesoporhyrin (CrMP), an inhibitor of HO-1 activity. Our data suggest that HO-1 might participate in anti-inflammatory effects of TauCl/TauBr possibly by inhibition of COX-2 activity and decrease of PGE(2) production.