IFN-γ inhibits basal and α-MSH-induced melanogenesis

Inflammatory cytokines are closely related to pigmentary changes. In this study, the effects of IFN-γ on melanogenesis were investigated. IFN-γ inhibits basal and α-MSH-induced melanogenesis in B16 melanoma cells and normal human melanocytes. MITF mRNA and protein expressions were significantly inhibited in response to IFN-γ. IFN-γ inhibited CREB binding to the MITF promoter but did not affect CREB phosphorylation. Instead, IFN-γ inhibited the association of CBP and CREB through the increased association between CREB binding protein (CBP) and STAT1. These findings suggest that IFN-γ inhibits both basal and α-MSH-induced melanogenesis by inhibiting MITF expression. The inhibitory action of IFN-γ in α-MSH-induced melanogenesis is likely to be associated with the sequestration of CBP via the association between CBP and STAT1. These data suggest that IFN-γ plays a role in controlling inflammation- or UV-induced pigmentary changes.