A8.22 Thiol-activated hydrogen sulfide donors and their anti-inflammatory potential in the mouse macrophage cell line RAW264

Abstract

Background Hydrogen sulfide (H 2 S) is an important signalling molecule that regulates many physiological (blood pressure) and pathophysiological (inflammation) processes in organs and cellular systems. Inorganic H 2 S donors like sodium hydrogen sulfide (NaHS) rapidly but uncontrollably release H 2 S leading to negative side effects (activation of MAPkinases etc.). Therefore, inducible H 2 S donors have recently emerged as useful tools for studying the molecular mechanism of H 2 S. In this study we report about the chemical and biological evaluation of a new class of organic H 2 S donors which release H 2 S only upon activation by thiols. Materials and methods The H 2 S releasing compounds 5a, 8a and yz-5–093 were synthesised and kindly provided by M Xian´s group (Washington, USA). H 2 S release under physiological pH range (PBS, pH 7.4) was measured with a H 2 S-selective microelectrode. In intact cells, H 2 S production was monitored by the fluorescent probe WSP-1. To evaluate the anti-inflammatory potential of the H 2 S donors in vitro , mouse macrophages (RAW264 cell line) were incubated for 1 h with different concentrations (10–100 µM) of compounds 5a, 8a and yz-5–093 before the cells were stimulated for 24 h with LPS. IL-6 and TNF-α levels in cell culture supernatants were quantified by enzyme-linked immunosorbent assays (ELISAs). Results All three compounds released H 2 S at similar concentrations. Cotreatment of RAW264 cells with compounds 5a, 8a and yz-5–093 downregulated LPS-induced IL-6 expression in a dose-dependent manner. TNF-α production was only affected at the highest concentration (100 µM). Conclusion We demonstrate that thiol-inducible H 2 S donors represent a new scientific tool which allows to mimic the slow and continous H 2 S generation process in vivo . These donors might have therapeutic benefits in the treatment of chronic inflammatory disorders such as rheumatoid arthritis.