Effect of Sulfur‐Containing Compounds on Hydrogen Sulfide Production in THP‐1 Differentiated Macrophages

Abstract

Hydrogen sulfide (H2S) is considered the third endogenous gaseous signaling transmitter. The H2S has been described as a target molecule for therapies on specific diseases, such as cardiovascular diseases and inflammatory processes. Garlic and glutathione (GSH) are examples of sulfur‐containing compounds that have been shown to modulate H2S production in erythrocytes and other specialized cells. However, such evidence has never been described in immune cells. Therefore, the aim of this study was to investigate the effect of aged garlic extract (AGE) and GSH on H2S production in macrophages. THP‐1 monocytes (0.7×106) were differentiated into macrophages using phorbol 12‐myristate 13‐acetate in a 96‐well plate. Once differentiated, the cells were pre‐incubated at 37°C in a humidified 5% CO2 atmosphere for 30 minutes with a fluorescent turn‐on H2S‐responsive probe (DP‐NBD – 150uM), synthesized according to Zhang et al. (2015). The cells were treated for 24 hours with GYY4137 (300uM), GSH (1mM), AGE (100mg/ml) or GSH+AGE. Cells were also treated for 24 hours with GSH and then 3 hours with AGE. The H2S production was identified using a fluorescent microscope and the fluorescence of DP‐NBD recorded. After the 24 hour incubation, GSH and AGE treatments alone had no effect on H2S production compared to non‐treated cells. Moreover, in the GSH (24 hours) + AGE (3 hours) treatment, the fluorescence intensity also did not differ from non‐treated cells. However, when the macrophages were incubated with GSH+AGE at the same time, the fluorescence was higher than non‐treated cells and comparable to the positive control. In conclusion, incubation with GSH and AGE together increased H2S production in THP‐1 differentiated macrophages after 24 hours of treatment, but this effect was not observed in the individual treatments. These results demonstrate a possible interaction between GSH and AGE in immune cells.Support or Funding InformationUF/IFAS Agriculture Experiment Station