Abstract
INTRODUCTION: Hydrogen sulfide (H(2)S) is a ubiquitous gas that has recently garnered significant interest as a potential therapeutic agent for various ischemic and inflammatory diseases. Therefore, effective H(2)S detection methods may be beneficial for translational research applications for these diseases. In the current study, a near-infrared H(2)S (NIR-HS) probe was synthesized and hypothesized that the probe would allow for qualitative assessment of H(2)S in biological systems. MATERIALS AND METHODS: The NIR-HS probe was synthesized and purified using chromatography. The ability of the NIR-HS probe to detect H(2)S was first determined in cell-free environments when H(2)S salts sodium sulfide (Na(2)S), sodium hydrosulfide (NaHS) and a H(2)S-slow-releasing donor (p-methoxyphenyl)morpholino-phosphinodithioic acid (GYY4137), were used. Three mammalian cell lines (HIEC6, HEK293T, and vertebral bone adherent mesenchymal stem cell) were treated with NaHS (H(2)S donor) or ZnCl(2) (negative control) in the presence of the NIR-HS probe. NIR-HS probe was also tested in cells that either overexpressed H2S synthases (CBS, CTH, and mercaptopyruvate sulfurtransferase) or had reduced levels of H2S synthases. The fluorescent responses of NIR-HS were determined by fluorescent microscopy and flow cytometry. RESULTS: In a cell-free system, the NIR-HS probe showed a statistically significant increase in fluorescence with the addition of Na(2)S, NaHS, or GYY4134 compared to vehicle alone, and dose-dependent responses to H(2)S donors. In mammalian cells, H(2)S donors increased and ZnCl(2) decreased the fluorescent responses of NIR-HS. Knocking down and overexpressing the endogenous H(2)S synthases altered the production of H(2)S, respectively. CONCLUSIONS: This NIR-HS probe was shown to be a useful compound in the detection of H(2)S in cell-free and cellular environments. Further studies are needed to demonstrate its use within in vivo applications of specific ischemic and inflammatory disease models prior to clinical translation.