P40 Cysteine-activated hydrogen sulphide donors and their anti-inflammatory potential in the human leukemic monocyte cell line U937

Abstract

H2S is an important gaseous signalling molecule and plays a crucial role in many physiological and pathophysiological processes. In this study we report about the biological evaluation of a new class of H2S donors (benzamide and penicillame derivatives), releasing H2S upon activation by cysteine or gutathione. Anti-inflammatory effects of the “classic” H2S donor NaHS were compared with chemically synthesized compounds. U937 cells were preincubated for 1 h with NaHS or with the cysteine-inducible H2S donors 5a, 5b, 8a and 8 l. H2S release was induced by the addition of cysteine. The cells were then stimulated for 24 h with LPS. Vice versa, U937 cells were stimulated for 6 h with LPS and then posttreated for 18 h with the same compounds. TNF-alpha and IL-6 levels were quantified by ELISA. Nitrite as a marker for iNOS activation was monitored by a commercially available kit. Both NaHS and the compounds 5a and 8a showed potent anti-inflammatory effects in U937 cells by downregulating TNF-alpha and IL-6 expression. In line with these results, nitrite production was also reduced. Significant anti-inflammatory effects of all compunds were observed only at concentrations above 100 μM. Notably, the effect of NaHS on TNF-alpha and IL-6 expression was significantly less pronounced compared to 5a and 8a. We conclude that cysteine-inducible donors represent a new class of controllable H2S donors which could mimic the slow and continous H2S generation process in vivo.