The Effects of Keratinocyte-derived Factors Involved in Transforming the Morphologies of Melanocyte and in Translocating Melanosomes to Keratinocyte

Yoon, Yong Hyun; Kim, Joo Young; Song, In Hwan; Sung, Eon Gi

Abstract

Keratinocyte-derived factors are involved in regulating the proliferation, differentiation or melanogenesis of melanocytes. To investigate the effects of keratinocyte-derived factors on the skin pigmentation, human melanocytes and keratinocytes were cultivated in the forms of pure melanocyte or keratinocyte culture system, co-culture system (melanocytes and keratinocytes were cultivated together in a vessel but they were separated with semipermeable membrane) or mixed culture system (melanocytes and keratinocytes were cultivated together in a vessel in mixed form). The authors studied the cellular features (dendritogenesis and area) and the tyrosinase activities and observed the electron microscopic structures for melanosome transfer. Melanocyte in co-culture system increased in the area (p.0.05) but not in the dendritogenesis compared with the melanocyte in pure culture system. The tyrosinase activities of co-culture system on the 2nd and 4th day revealed higher compared with the ones of the pure and mixed culture system (p.0.05). In the co-culture system, the tyrosinase activities were gradually decreased with the lapse of time and vice versa in the pure and mixed culture system. On the 6th day culture, all of the three melanocyte culture systems showed the same tyrosinase activities. In spite of high tyrosinase activities in the medium, there were no tyrosinase activities in keratinocytes with the co-culture system. In transmission electron microscopic findings, there were scant of melanosomes in keratinocytes with the co-culture and mixed culture systems. In conclusion, keratinocyte-derived factors modulate the activities and melanogenesis of melanocytes but there were no effects on melanosome transfer to keratinocytes.