Hydrogen sulfide diminishes the levels of thymic stromal lymphopoietin in activated mast cells.

Bamboo salt (BS) is a Korean traditional type of salt and has been reported to have therapeutic effects on allergic inflammation. Thymic stromal lymphopoietin (TSLP) aggravates inflammation in the pathogenesis of allergic reactions, such as allergic rhinitis (AR). To confirm an active compound of BS, we investigated the effect of sulfur, a compound of BS, on the levels of TSLP in a human mast cell line, HMC-1 cells and a mouse model of AR using hydrogen sulfide (H2S) donor, sodium hydrosulfide (NaSH). We treated NaSH or BS in HMC-1 cells and activated the HMC-1 cells with phorbol myristate acetate and calcium ionophore A23187 (PMACI). ELISA for the production measurement of TSLP, PCR for the mRNA expression measurement of TSLP, and western blot analysis for the expression measurement of upstream mediators were performed. Mice were treated with NaSH and sensitized with ovalbumin (OVA). The levels of TSLP were measured in serum and nasal mucosa tissue in an OVA-induced AR mouse model. NaSH or BS diminished the production and mRNA expression of TSLP as well as interleukin (IL)-6 and tumor necrosis factor (TNF)-α in the PMACI-activated HMC-1 cells. NaSH or BS diminished the level of intracellular calcium in the PMACI-activated HMC-1 cells. NaSH or BS reduced the expression and activity of caspase-1 in the PMACI-activated HMC-1 cells. And NaSH or BS inhibited the expression of receptor interacting protein-2 and the phosphorylation of extracellular signal-regulated kinase in the PMACI-activated HMC-1 cells. The translocation of NF-κB into the nucleus as well as the phosphorylation and degradation of IκBα in the cytoplasm were diminished by NaSH or BS in the PMACI-activated HMC-1 cells. Furthermore, NaSH inhibited the production of TSLP, IL-6, and IL-8 in TNF-α-activated HMC-1 cells. Finally, the administration of NaSH showed a decrease in number of rubs on mice with OVA-induced AR. And the levels of immunoglobulin E and TSLP in the serum and the level of TSLP in the nasal mucosa tissue of the OVA-induced AR mice were reduced by NaSH. In conclusion, these findings show that H2S, as an active compound of BS is a potential agent to cure allergic inflammation.