Tenchini M L, Adams J C, Gilberty C, Steel J, Hudson D L, Malcovati M, Watt F M
Università degli Studi di Milano, Dipartimento di Biologie e Genetica per le Scienze Mediche, Italy.
Cell Adhes Commun. 1993 May;1(1):55-66. doi: 10.3109/15419069309095681.
It is well established that integrins mediate keratinocyte adhesion to extracellular matrix proteins, but, in addition, there is some evidence that they mediate intercellular adhesion. We have investigated the role of integrins in keratinocyte-keratinocyte adhesion by adding anti-integrin antibodies to cells in three assays that differ according to the calcium ion concentration of the medium, the presence or absence of an adhesive substrate (glass or tissue culture plastic) and the timing of antibody addition. As previously reported by Larjava et al., (J. Cell Biol. 110:803-815), a monoclonal antibody to the beta 1 subunit perturbed cell-cell adhesion when added to adherent monolayers in low calcium medium (0.1 mM calcium ions), but did not prevent cell-cell adhesion or stratification induced by raising the level of calcium ions to 1.8mM (the concentration in standard medium). Monoclonal antibodies to both the alpha 3 and beta 1 subunits inhibited the attachment, spreading and motility of keratinocytes in low or standard calcium medium when added at the time of plating; however, they had only a modest effect on the accumulation of cells in adherent clusters. Aggregation of keratinocytes in suspension required a calcium ion concentration of greater than 0.1mM and was not inhibited by any of a large panel of anti-integrin antibodies, including three new antibodies that recognise alpha 2 beta 1. We conclude that any inhibitory effects of individual anti-integrin antibodies on cell-cell adhesion are abrogated by a calcium ion concentration above 0.1mM and that in low calcium medium at least some of the inhibition of cell-cell adhesion is a consequence of the inhibition of cell-substrate adhesion and motility.
整合素介导角质形成细胞与细胞外基质蛋白的黏附，这一点已得到充分证实，但除此之外，有证据表明它们也介导细胞间黏附。我们通过在三种不同的实验中向细胞添加抗整合素抗体，研究了整合素在角质形成细胞间黏附中的作用。这三种实验根据培养基中钙离子浓度、是否存在黏附底物（玻璃或组织培养塑料）以及抗体添加时间而有所不同。正如Larjava等人之前所报道的（《细胞生物学杂志》110:803 - 815），当在低钙培养基（0.1 mM钙离子）中添加针对β1亚基的单克隆抗体时，会干扰贴壁单层细胞间的黏附，但当钙离子浓度提高到1.8 mM（标准培养基中的浓度）时，并不会阻止细胞间黏附或分层。针对α3和β1亚基的单克隆抗体在接种时添加，会抑制低钙或标准钙培养基中角质形成细胞的附着、铺展和运动；然而，它们对贴壁细胞簇中细胞的聚集只有适度的影响。悬浮状态下角质形成细胞的聚集需要钙离子浓度大于0.1 mM，并且不受一大组抗整合素抗体的抑制，包括三种识别α2β1的新抗体。我们得出结论，高于0.1 mM的钙离子浓度可消除单个抗整合素抗体对细胞间黏附的任何抑制作用，并且在低钙培养基中，至少部分细胞间黏附的抑制是细胞 - 底物黏附及运动受到抑制的结果。
