A novel slow-releasing hydrogen sulfide donor, FW1256, exerts anti-inflammatory effects in mouse macrophages and in vivo

Exogenous hydrogen sulfide (H₂S) is known to exert anti-inflammatory effects both in macrophages and in animal models. In this study, we first showed that NaHS caused a concentration dependent reduction in TNFα and IL-6 secretion in LPS-stimulated RAW264.7 macrophages in the absence of cell death. Thereafter, we screened a series of novel slow H₂S donors for similar activity. One such compound, FW1256, concentration dependently decreased TNFα, IL-6, PGE₂ and NO generation in LPS-stimulated RAW264.7 macrophages and BMDMs. FW1256 also significantly reduced IL-1β, COX-2 and iNOS mRNA and protein in LPS-stimulated RAW264.7 macrophages. Mechanistically, FW1256 decreased NFκB activation as evidenced by reduced cytosolic phospho-IκBα levels and reduced nuclear p65 levels in LPS-stimulated RAW264.7 macrophages treated with FW1256. Using a H₂S fluorescent probe in FW1256-treated RAW264.7 macrophages, H₂S release from FW1256 was apparent over a period of 24h in these cells. Moreover, the effect of FW1256 on TNFα and IL-6 by FW1256 in LPS-stimulated RAW264.7 macrophages was reversed by treatment with the H₂S scavenger, vitamin B_12a. FW1256 had no cytotoxic effect on LPS-stimulated RAW264.7 macrophages or BMDMs. In vivo, FW1256 administration also reduced IL-1β, TNFα, nitrate/nitrite and PGE₂ levels in LPS-treated mice. We show here a novel slow H₂S-releasing compound that exerts anti-inflammatory effects in macrophages and in vivo. FW1256 may be a useful tool to study the biological effects of exogenous H₂S and could also have future therapeutic value in inflammatory conditions.