SZ95 sebocytes induce epidermal melanocyte dendricity and proliferation in vitro

The regulatory effects of sebocytes on melanocytes (HMel) are unknown. In this study, SZ95 sebocytes co-cultured with HMel, whether in direct cell contact or with SZ95 sebocytes in inserts, resulted in epidermal HMel flattening with increase in surface area and multiple small dendrites formation. Only in high Ca(2+) level and direct cell contact co-culture, the HMel dendrites were remarkably long and preferentially targeted and attached to SZ95 sebocytes. Likewise, only high Ca(2+) SZ95 sebocyte conditioned medium stimulated HMel proliferation in a time-dependent manner at days 9 (142.9%, P < 0.01) and 12 (179.2%, P < 0.0001) of incubation when compared with day 0. In contrast, melanin contents significantly decreased on incubation with high Ca(2+) SZ95 sebocytes in comparison with low Ca(2+) SZ95 sebocytes at days 6 (P < 0.01) and 9 (P < 0.05) of incubation. These results denote that sebocytes also modulate HMel functions and may contribute to skin colour in sebaceous glands-rich body regions.