Zambruno G, Marchisio P C, Melchiori A, Bondanza S, Cancedda R, De Luca M
Clinica Dermatologica, Università di Modena, Italy.
J Cell Sci. 1993 May;105 ( Pt 1):179-90. doi: 10.1242/jcs.105.1.179.
Integrin receptors of human melanocytes in vivo and of melanocytes isolated and cultured from in vitro reconstituted normal human epidermis were investigated. Melanocytes were studied by high-resolution immunocytochemistry of in situ epidermis and were found to expose only the integrin subunits alpha 3, alpha 6, alpha v and beta 1 on their plasma membrane surface. Instead, cultured normal melanocytes expressed alpha 3 beta 1, alpha 5 beta 1, alpha 6 beta 1 and alpha v beta 3, which were immunoprecipitated from both metabolically and surface-labeled cells. Beta 1 integrins were diffused on the adhesion surface, while alpha v beta 3 was clustered in focal contacts both in control cells and upon dendrite induction with phorbol 12-myristate 13-acetate (PMA). The functional roles of integrins were studied in vitro by cell adhesion, spreading and migration assays. The sum of the data indicated that, in normal human melanocytes: (i) adhesion to defined substrata is mainly mediated by specific beta 1 integrins; (ii) spreading is mainly modulated by alpha v beta 3; (iii) the beta 1 and beta 3 heterodimers cooperate in regulating migration. The in vitro expression of two integrins (alpha v beta 3 and alpha 5 beta 1) that are not exposed in situ, and their role in the spreading and migratory properties of melanocytes, strongly suggest that they are involved in regenerating a normally pigmented epidermis during wound healing by controlling melanocyte spreading and migration over a provisional matrix. Tumor promoters, such as PMA, selectively increased the expression of alpha 3 beta 1. We suggest that this integrin might be involved in melanocyte migration on the newly formed basement membrane during wound healing as well as in intercellular recognition of adjacent keratinocytes.
对体内人黑素细胞以及从体外重建的正常人表皮中分离培养的黑素细胞的整合素受体进行了研究。通过对原位表皮进行高分辨率免疫细胞化学研究黑素细胞，发现它们仅在质膜表面暴露整合素亚基α3、α6、αv和β1。相反，培养的正常黑素细胞表达α3β1、α5β1、α6β1和αvβ3，这些整合素可从代谢标记和表面标记的细胞中免疫沉淀出来。β1整合素在黏附表面呈弥散分布，而αvβ3在对照细胞以及用佛波酯12 -肉豆蔻酸酯13 -乙酸酯（PMA）诱导树突形成时均聚集在黏着斑中。通过细胞黏附、铺展和迁移实验在体外研究了整合素的功能作用。所有数据表明，在正常人黑素细胞中：（i）对特定底物的黏附主要由特定的β1整合素介导；（ii）铺展主要由αvβ3调节；（iii）β1和β3异二聚体协同调节迁移。两种在原位未暴露的整合素（αvβ3和α5β1）在体外的表达及其在黑素细胞铺展和迁移特性中的作用，强烈表明它们通过控制黑素细胞在临时基质上的铺展和迁移，参与伤口愈合过程中正常色素沉着表皮的再生。肿瘤促进剂，如PMA，选择性增加α3β1的表达。我们认为这种整合素可能参与伤口愈合过程中黑素细胞在新形成的基底膜上的迁移以及相邻角质形成细胞的细胞间识别。
