Development of a Digital Image-Based Method to Screen Molecules That Regulate Melanization.

Vitiligo vulgaris is an acquired disorder that is thought to arise from the suppression of melanin synthesis by melanocytes in the basal epidermal layer. To develop therapeutic agents for vitiligo vulgaris, it is critical to identify compounds that promote melanization. In this study, we established a digital image-based method to quantify melanization that does not require biochemical procedures. B16F10 cells were seeded in a white-bottom 96-well microplate. After treatment with or without α-melanocyte-stimulating hormone, followed by fixation of the cells, digital images of the microplates were captured, and the total signal intensity of each well on the image was measured. The extent of melanization in the cells in each well was defined after the subtraction of the signal from the corresponding blank well. This method was found to quantify melanization more sensitively than the conventional technique that measures the absorbance of cell lysates at UV-A wavelengths. We obtained statistical parameters showing that this method was applicable to a high-throughput screening assay; thus, this method appears to be useful for screening and identifying molecules that suppress or promote melanization, the latter of which may be developed as therapeutic agents for vitiligo vulgaris.