1183 Expression of adhesion molecules and basic fibroblast growth factor 2 in non-segmental vitiligo-derived primary melanocytes

Primary melanocytes isolated from non-depigmented skin of two Japanese patients with non-segmental vitiligo were difficult to grow in culture. Adding a ROCK inhibitor to the culture medium dramatically increased the yield of pure melanocytes. RT-qPCR analysis of vitiligo-derived primary melanocytes revealed significantly decreased MITF mRNA levels compared to normal melanocytes. In contrast, SCF mRNA expression levels were significantly higher in co-cultures of vitiligo-derived primary melanocytes and normal keratinocytes than in co-cultures of normal melanocytes and normal keratinocytes. The surrounding tissue environment in vitiliginous skin, especially keratinocytes, could play a role in recovering the down-regulated expression of MITF in non-lesional vitiligo melanocytes that could lead to a return to normal proliferation, differentiation and melanogenesis of melanocytes in non-lesional vitiligo via the up-regulation of SCF. RT-qPCR analysis of melanocyte-related adhesion molecules (E-cadherin, DDR1, GPNMB and HSD17β1) in vitiligo-derived primary melanocytes revealed significantly decreased mRNA levels of those adhesion molecules compared to normal melanocytes. Those mRNA expression levels were significantly higher in co-cultures of vitiligo-derived primary melanocytes and normal keratinocytes than in co-cultures of normal melanocytes and normal keratinocytes. The in vivo friction of perilesional non-segmental vitiligo skin induces the detachment of living melanocytes from the basal layer followed by the transepidermal migration and eventual death of the detached melanocytes. bFGF2 expression levels both in vitiligo-derived primary melanocytes and in co-cultures of vitiligo-derived primary melanocytes and normal keratinocytes were significantly higher compared to normal melanocytes based on RT-qPCR analysis and confocal laser immunofluorescence microscopy. These results suggest that bFGF2 plays an active role in vitiligo development and participates in its pathogenesis and might be involved in the pathogenetic chain of events leading to non-segmental vitiligo.