Melanosome uptake is associated with the proliferation and differentiation of keratinocytes

• DOI: 10.1007/s00403-013-1422-x
• Publication Date: 2013-10-30T15:38:22Z
• Authors: Hye-In Choi; Kyung-Cheol Sohn; Dong-Kyun Hong; Young Lee; Chang Deok Kim; Tae-Jin Yoon; Jin Woon Park; Sunggyun Jung; Jeung-Hoon Lee; Young Ho Lee
• Keywords: Keratinocytes; Melanins; 0301 basic medicine; 03 medical and health sciences; Melanosomes; Humans; Receptor, PAR-2; Biological Transport; Calcium; Cell Differentiation; Cell Line, Transformed; Cell Proliferation

Melanosomes are synthesized in melanocytes and transferred to neighboring keratinocytes. However, the associations of melanosome uptake with the proliferation and differentiation of keratinocytes are not fully understood. We examined the associations of melanosome uptake with keratinocyte differentiation and proliferation. SV40T-transformed human epidermal keratinocytes (SV-HEKs) were treated with isolated melanosomes. The effects of melanosome uptake on the proliferation and differentiation of the keratinocytes were analyzed by Western blotting and flow cytometry. The relationship between melanosome uptake and keratinocyte differentiation status was verified by determining the melanin content in the cells. Melanosomes reduced the proliferation of SV-HEKs in a dose-dependent manner, but did not induce differentiation. Melanosome uptake was higher in differentiating keratinocytes compared to non-differentiating keratinocytes, and inhibited significantly by PAR-2 inhibitor. Melanosomes inhibit keratinocyte proliferation. Moreover, melanosome uptake is influenced by keratinocyte differentiation status, being highest in mid-stage differentiating keratinocytes in a PAR-2 dependent manner.