Disulfanyl peptide decreases melanin synthesis via receptor-mediated ERK activation and the subsequent downregulation of MITF and tyrosinase.

Abstract

Bioactive peptides are commonly used in cosmeceutical purpose. This study was performed to search for an effective and short hypopigmenting peptide using normal human melanocytes as a screening model. A peptide that exhibits multitarget activities will be a promising peptide. Depigmenting effects were tested in normal human melanocytes. One peptide was selected, and signalling mechanism was investigated by Western blotting and immunofluorescent microscopic examination. A novel hypopigmenting peptide (dSHP) has been found to inhibit the production of melanin. This peptide significantly decreases tyrosinase activity but was not effective in a direct in vitro assay. It also induces the prolonged activation of ERK, and subsequently downregulates the levels of MITF. PD98059 abolished the dSHP-induced downregulation of MITF. These findings indicate that the dSHP-induced activation of ERK contributes to a reduced melanin synthesis via the downregulation of MITF. Fluorescent microscopic studies were consistent with such findings. Pertussis toxin reverses the downregulation of MITF, which means that the receptor-mediated ERK activation is involved. Moreover, it was also found that downregulation of MITF was clearly inhibited by lysosomal inhibitor (chloroquine). Novel tetrapeptide dSHP reduces the melanin synthesis by a receptor-mediated pathway. Furthermore, dSHP works by ERK activation and key transcription factor MITF degradation. Thus, it may be a good candidate as an effective hypopigmenting cosmetic agent.