Control of melanosome transfer by promoting shrinkage or expansion of melanocyte dendrites

Melanosomes synthesized within melanocytes are transferred to keratinocytes through melanocyte dendrites, resulting in a constant supply of melanin to the epidermis which determines skin pigmentation. Theoretically, if we can find an effective way to control this supply of melanin to the epidermis, skin colour could be darkened or lightened. The objective of this study was to find safe and effective methods to inhibit or promote melanosome transfer by the shrinkage or expansion of melanocyte dendrites. Methylophiopogonanone B and centaureidin inhibited melanosome transfer to keratinocytes as well as melanocyte dendrite outgrowth. Methylswertianin and comfrey extract promoted not only melanosome transfer to keratinocytes but also expansion of melanocyte dendrites. Methylophiopogonanone B and centaureidin suppressed pigmentation in a three‐dimensional skin culture model through the inhibition of melanocyte dendrite outgrowth. Methylswertianin and comfrey extract activated pigmentation in a three‐dimensional skin culture model by expansion of melanocyte dendrites. Our experimental findings suggest the possibility of manipulating human skin colour by controlling melanosome transfer to cause shrinkage or expansion of dendrites. A combination of effective agents, in addition to the ones identified in this work, could result in the creation of very unique cosmetic products that would precisely control the darkening or lightening of skin tone.