On the role of melatonin in skin physiology and pathology

Area of Science:

• Dermatology and Skin Biology
• Biochemistry
• Molecular Biology

Background:

• Melatonin is recognized for its roles in skin functions like hair cycling, pigmentation, and melanoma.
• Melatonin receptors are present in various skin cells, including keratinocytes, melanocytes, and fibroblasts.
• Melatonin demonstrates protective effects against UV-induced skin damage and possesses antioxidant properties.

Purpose of the Study:

• To investigate the presence and function of the melatonin biosynthetic pathway in the skin.
• To confirm the in vivo synthesis and metabolism of melatonin within skin.
• To explore the potential therapeutic applications of melatonin in skin health and disease management.

Main Methods:

• Analysis of gene and protein expression for key enzymes in the melatonin pathway (tryptophan hydroxylase, serotonin N-acetyl-transferase, hydroxyindole-O-methyltransferase).
• Enzymatic activity assays in skin and skin cell extracts.
• In vivo studies using hamster skin organ culture and melanoma cell lines to demonstrate melatonin synthesis and metabolism.

Main Results:

• The biochemical machinery for synthesizing melatonin from l-tryptophan is expressed in the skin.
• Genes, proteins, and enzymatic activities involved in melatonin biosynthesis were detected in skin and skin cells.
• Initial evidence for in vivo melatonin synthesis and metabolism was observed in hamster skin organ culture and a melanoma line.

Conclusions:

• Melatonin can be synthesized locally within the skin, suggesting an intrinsic protective mechanism.
• Locally synthesized or topically applied melatonin may buffer environmental and internal stresses, preserving skin integrity and homeostasis.
• Melatonin holds potential for protecting against solar radiation and managing various skin diseases.