Fargesin inhibits melanin synthesis in murine malignant and immortalized melanocytes by regulating PKA/CREB and P38/MAPK signaling pathways.

Fargesin is commonly used in the treatment of allergic rhinitis, inflammation, sinusitis and headache.The aim of the study is to investigate a new function of fargesin against melanin production and its underlying molecular mechanism.B16F10 mouse melanoma cells, Melan-a and human epidermal melanocytes were treated with different concentrations of fargesin for the indicated time. The extracellular and cellular melanin content was detected by spectrometry at 490 nm and 405 nm, respectively. RT-qPCR and Western blot analysis were used to exam the expression of melanogenic enzymes and the activities of PKA/CREB and p38 MAPK pathway components. Zebrafish was used as an in vivo model for studying the function of fargesin in regulating melanogenesis.Fargesin effectively inhibited melanin production at moderate dose in mouse B16F10 melanoma cells, normal melanocyte cell lines and zebrafish. The expression of microphthalmia-associated transcription factor (MITF), its downstream melanogenic enzymes and tyrosinase activity were also strongly reduced by fargesin. Moreover, the increase of melanin production induced by UVB and forskolin could be fully reversed by fargesin treatment. Fargesin also effectively inhibited the activation of PKA/CREB and p38 MAPK as well as their interactions, which in turn is responsible for the expression of MITF and melanogenic enzymes.These results show that fargesin can function as an anti-melanogenic agent, at least in part, by inhibiting PKA/CREB and p38/MAPK signaling pathways. Therefore, fargesin and its derivatives may potentially be used for preventing hyperpigmentation disorders in the future.