Epidermal Keratinocytes from Light vs. Dark Skin Exhibit Differential Degradation of Melanosomes
Epidermal Keratinocytes from Light vs. Dark Skin Exhibit Differential Degradation of Melanosomes
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DOI：
10.1038/jid.2011.22
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发表时间：
2011-06-01
影响因子：
6.5
通讯作者：
Boissy, Raymond E.
中科院分区：
文献类型：
--
作者：
Ebanks, Jody P.;Koshoffer, Amy;Boissy, Raymond E.
传统上，皮肤色泽的改善是通过中断或减弱黑素生成和/或黑素小体转移来实现的。色素黑素小体的转移后修饰为调节皮肤色素沉着提供了一条诱人而独特的途径。黑素小体在角质形成细胞(KC)终末分化过程中的处理以及在明暗皮肤(LS和DS)之间观察到的降解性变异性仍然是一个谜。为了评估这一点，我们开发了一个模型系统来研究培养的人KCs丢失荧光标记和分离的黑素小体。用透射电子显微镜和间接免疫荧光共聚焦显微镜对黑素小体丢失的程度进行了定性评估，并用流式细胞术进行了定量评估。结果表明，黑素小体被整合到亮和暗角质形成细胞(LKCs和DKCs)的细胞质中，并运输到核周区域。48小时内，共聚焦显微镜图像显示LKC表现出加速的黑素小体丢失。然后用流式细胞术对这种与时间相关的二醋酸羧基荧光素(CFDA)荧光减弱进行定量分析。与共聚焦分析的结果一致的是，在48小时的时间范围内，LKC似乎比DKCS更有效地丢失黑素体。这些实验表明，与DS相比，LS来源的KCs中黑素小体的丢失速度更快。
Modification of skin complexion coloration has traditionally been accomplished by interruption or attenuation of melanogenesis and/or melanosome transfer. Post-transfer modification of pigmented melanosomes provides an attractive and distinct avenue of modulating skin pigmentation. The processing of melanosomes during keratinocyte (KC) terminal differentiation and the degradative variability observed between light and dark skin (LS and DS) remains enigmatic. To evaluate this, we developed a model system to investigate the loss of fluorescently labeled and isolated melanosomes by cultured human KCs. The extent of melanosome loss has been qualitatively assessed using transmission electron microscopy and indirect immunofluorescence with confocal microscopy, and quantitatively assessed using flow cytometry analysis. Results show that melanosomes are incorporated into the cytoplasm of both light and dark keratinocytes (LKCs and DKCs) and trafficked to a perinuclear region. Within 48 hours, confocal microscopy images suggest that LKCs display accelerated melanosome loss. This time- dependent decrease in carboxyfluorescein diacetate (CFDA) fluorescence was then quantitatively analyzed using flow cytometry. Consistent with the results of the confocal analysis, over a 48-hour time frame, LKCs appear to lose melanosomes more efficiently than DKCs. These experiments show that melanosomes are more rapidly lost in KCs derived from LS as opposed to DS.