Hydrogen Sulfide Promotes Cell Proliferation and Melanin Synthesis in Primary Human Epidermal Melanocytes

BACKGROUND/AIM: Hydrogen sulfide (H2S) has been found to act as a physiological intercellular messenger to regulate cell survival. In this study, we evaluated whether H2S could promote cell proliferation and melanin synthesis in human epidermal melanocytes (HEMs). METHODS: Primary HEMs were cocultured with sodium hydrosulfide (NaHS, the most widely used H2S donor) or endogenously overexpressed with cystathionine-γ-lyase (CSE) gene, which is the most predominant H2S-producing enzyme. Then, cell viability, intracellular melanin content, tyrosinase (TYR) activity, and expression of microphthalmia-associated transcription factor (MITF), TYR, together with TYR-related protein 1 (TRP-1) in both transcript and protein levels, were detected. RESULTS: We first confirmed that NaHS (10-100 μm) increased cell viability, intracellular melanin content, and TYR activity in a dose-dependent manner. Then, we found that endogenous H2S production also promoted cell proliferation, intracellular melanin content, and TYR activity. In addition, we observed the mRNA and protein expression of MITF, TYR, and TRP-1 was significantly up-regulated after NaHS treatment and CSE gene transfection. CONCLUSIONS: This study demonstrates that H2S promotes cell proliferation and melanin synthesis in HEMs, which indicates pharmacologic regulation of H2S may be potential treatment for skin disorders caused by loss of melanocytes or dysfunction of melanogenesis.