Department of Dermatology, Yanbian University Hospital, 1327 Juzi Street, Yanji City, Jilin Province, 133000, China.
Br J Dermatol. 2018 Mar;178(3):632-639. doi: 10.1111/bjd.15651. Epub 2018 Jan 16.
Melanocytes are generally characterized by the basic ability of melanin synthesis and transfer to adjacent keratinocytes. This constitutes an individual skin phenotype and provides epidermal protection from various stimuli, such as ultraviolet irradiation, through a complex process called melanogenesis, which can be regulated by autocrine or paracrine factors. Recent evidence has revealed the paracrine effects of keratinocytes on melanogenesis by secreting cytokines, including α-melanocyte stimulating hormone and endothelin-1. In addition to keratinocytes, there are other types of cells in the skin, such as fibroblasts and immune cells, which are also actively involved in the regulation of melanocyte behaviour through the production of paracrine factors. In addition, extracellular matrix proteins, which are secreted mainly by skin-resident cells, not only play direct roles in regulating melanocyte morphology and functions but also provide structural support between the epidermis and dermis to control the distribution of various secreted cytokines from keratinocytes and/or fibroblasts, which are potentially involved in the regulation of melanogenesis. Moreover, understanding the origin of melanocytes (neural crest cells) and the presence of nerve endings in the epidermis can reveal the intimate contact between melanocytes and cutaneous specific nervous system proteins. Melanocytes are associated with all these networks with corresponding receptors expressed on the cell surface. In this review, we provide an overview of recent advances in determining the intimate relationships between melanocytes and their surrounding elements, which provide insights into the complex nature of the regulation of melanogenesis.
黑素细胞通常具有合成和向相邻角质形成细胞转移黑色素的基本能力。这构成了个体的皮肤表型，并通过一种复杂的过程——黑素生成，为表皮提供了对各种刺激（如紫外线照射）的保护，这种过程可以通过自分泌或旁分泌因子来调节。最近的证据表明，角质形成细胞通过分泌细胞因子（包括α-促黑素细胞激素和内皮素-1）对黑素生成具有旁分泌作用。除了角质形成细胞，皮肤中还有其他类型的细胞，如成纤维细胞和免疫细胞，它们也通过产生旁分泌因子积极参与调节黑素细胞的行为。此外，细胞外基质蛋白主要由皮肤常驻细胞分泌，不仅直接调节黑素细胞的形态和功能，而且在表皮和真皮之间提供结构支持，以控制来自角质形成细胞和/或成纤维细胞的各种分泌细胞因子的分布，这些细胞因子可能参与调节黑素生成。此外，了解黑素细胞（神经嵴细胞）的起源和表皮中神经末梢的存在，可以揭示黑素细胞与皮肤特定神经系统蛋白之间的密切联系。黑素细胞与所有这些网络都有相应的受体表达在细胞表面。在这篇综述中，我们概述了最近在确定黑素细胞与其周围成分之间的密切关系方面的进展，这些进展为黑素生成调节的复杂性提供了新的认识。
