Inhibition of melanogenesis by tyrosinase siRNA in human melanocytes.

Tyrosinase (TYR) plays a critical role in cellular melanogenesis and, thus, has been the major target of pharmacological approaches for the control of skin pigmentation. This study examined an alternative molecular approach using TYR-small interfering RNA (siRNA) to control melanogenesis in the human melanocytes. Both the mRNA and protein levels of TYR were significantly lowered by TYR-siRNA treatment, whereas TYR-related protein 1 and TYR-related protein 2 displayed no such changes. TYR-siRNA treatment inhibited the cellular melanin synthesis from the externally supplied TYR substrate L-tyrosine. TYR-siRNA also suppressed melanin synthesis and decreased the viability of cells exposed to ultraviolet radiation, supporting a critical role of melanin in protection against ultraviolet radiation. These results suggest that molecular approaches using siRNA targeted to the enzymes of melanogenic pathway may provide a novel strategy for the control of cell pigmentation.