Modulatory effects of oxytocin on normal human cultured melanocyte proliferation, migration, and melanogenesis

Melanocytes are specialized melanin-producing neural crest-derived cells. Melanocyte proliferation and melanin production (i.e., melanogenesis) are crucial for determining skin color. Disruption of these processes can cause pigmentary skin disorders, including hypo-pigmentary disorders such as vitiligo and hyper-pigmentary disorders such as melasma. Understanding these processes is important for discovering new targets to tackle these skin disorders. Therefore, this study aimed to investigate the effects of oxytocin (OXT) on melanocyte functions. Normal Human Cultured Melanocytes (NHCM) were treated with different OXT doses to investigate OXT effects and mechanisms on NHCM proliferation, migration, and on melanogenesis. OXT significantly increased NHCM proliferation and migration in a dose-dependent manner after 72 h of treatment. In addition, OXT dose-dependently upregulated melanogenesis-related microphtalmia-associated transcription factor, tyrosinase, tyrosinase-related protein (TYRP)-1, and TYRP-2 expression accompanied by an increased trend in melanosome number and maturation stage. Furthermore, OXT at concentrations (62.5-125 nM) increased melanin production. These findings suggest the involvement of OXT receptor (OXTR). In addition, this study demonstrates that OXT stimulates melanocyte proliferation, migration, with a tendency toward melanosome maturation, while it modulates melanin production in a dose-dependent manner. Thus, OXT system including its receptor OXTR may be a potential therapeutic target for skin pigmentary disorders.