Charles Institute of Dermatology, School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland.
Conway Institute of Biomedical and Biomolecular Science, University College Dublin, D04 V1W8 Dublin, Ireland.
Int J Mol Sci. 2023 Aug 15;24(16):12809. doi: 10.3390/ijms241612809.
The visual appearance of humans is derived significantly from our skin and hair color. While melanin from epidermal melanocytes protects our skin from the damaging effects of ultraviolet radiation, the biological value of pigmentation in the hair follicle, particularly on the scalp, is less clear. In this study, we explore the heterogeneity of pigment cells in the human scalp anagen hair follicle bulb, a site conventionally viewed to be focused solely on pigment production for transfer to the hair shaft. Using c-KIT/CD117 microbeads, we isolated bulbar c-KIT-positive and c-KIT-negative melanocytes. While both subpopulations expressed MITF, only the c-KIT-positive fraction expressed SOX10. We further localized bulbar melanocyte subpopulations (expressing c-KIT, SOX10, MITF, and DCT) that exhibited distinct/variable expression of downstream differentiation-associated melanosome markers (e.g., gp100 and Melan-A). The localization of a second 'immature' SOX10 negative melanocyte population, which was c-KIT/MITF double-positive, was identified outside of the melanogenic zone in the most peripheral/proximal matrix. This study describes an approach to purifying human scalp anagen hair bulb melanocytes, allowing us to identify unexpected levels of melanocyte heterogeneity. The function of the more immature melanocytes in this part of the hair follicle remains to be elucidated. Could they be in-transit migratory cells ultimately destined to synthesize melanin, or could they contribute to the hair follicle in non-melanogenic ways?
人类的外貌主要来自于我们的皮肤和头发颜色。虽然表皮黑素细胞中的黑色素能保护我们的皮肤免受紫外线辐射的伤害，但毛囊中色素的生物学价值，尤其是头皮上的，就不那么清楚了。在这项研究中，我们探索了人类头皮生长期毛囊球部色素细胞的异质性，这个部位通常被认为仅专注于产生色素并转移到毛发轴上。我们使用 c-KIT/CD117 微珠分离了球部 c-KIT 阳性和 c-KIT 阴性黑素细胞。虽然这两个亚群都表达了 MITF，但只有 c-KIT 阳性亚群表达了 SOX10。我们进一步定位了球部黑素细胞亚群（表达 c-KIT、SOX10、MITF 和 DCT），它们表现出不同/可变的下游分化相关黑素体标志物（如 gp100 和 Melan-A）的表达。第二个“不成熟”的 SOX10 阴性黑素细胞群体，c-KIT/MITF 双阳性，被定位在最外周/近端基质的黑素生成区之外。这项研究描述了一种纯化人类头皮生长期毛囊球部黑素细胞的方法，使我们能够识别出人意料的黑素细胞异质性水平。这些毛囊中更不成熟的黑素细胞的功能仍有待阐明。它们可能是处于迁移状态的过渡细胞，最终注定要合成黑色素，还是它们以非黑素生成的方式为毛囊做出贡献？
