Human umbilical vein endothelial cells were found to attach and partially spread on human tenascin. The attachment of endothelial cells to tenascin results in elongated cells with interconnecting processes and is distinct from the flattened appearance of endothelial cells on fibronectin, collagen, vitronectin or laminin substrata, suggesting a role for tenascin in modulating cell adhesion and motility. Endothelial attachment to tenascin was partially inhibitable by the SRRGDMS peptide derived from human tenascin and completely inhibitable by anti-integrin antibodies to α2β1 and αvβ3 Endothelial cell attachment to tenascin could be inhibited up to 80% with anti-α2 and anti-β1 monoclonal antibodies P1E6 and P4C10, respectively, and this was associated with a complete loss in cell spreading. In contrast, pretreatment of endothelial cells with the anti-αvβ3 monoclonal antibody LM609, resulted in a 35% inhibition in cell attachment but did not alter cell spreading. In combination the anti-α2 and anti-αvβ3 antibodies, could completely abrogate cell spreading and attachment to tenascin-coated surfaces. Affinity purification of 125I-labeled endothelial cell ex-tract on a tenascin matrix column followed by immunoprecipitation with monoclonal antibodies to different integrin α and β subunits resulted in the identification of α2β1 and αvβ3 integrins, respectively, as tenascin binding receptors. Collagen affinity-purified α2β1 receptor from endothelial cells bound not only to collagen and laminin but also to tenascin in a radio receptor binding assay. The results demonstrate that α2β1 and αvβ3 mediate distinct endothelial cell interactions with tenascin; cell spreading and cell binding, respectively. Binding by αvβ3 is mediated by the SRRGDMS site on tenascin, whereas the α2β1 binding site remains undefined. The interaction of α2β1 and αvβ3 with tenascin may be regulated in a cell type-specific manner as evidenced by the binding of endothelial cell α2β1 and αvβ3 to tenascin, and the lack of binding by the same receptors on osteosarcoma MG63 to tenascin.
|Original language||English (US)|
|Number of pages||12|
|Journal||Journal of cell science|
|State||Published - 1993|
- Cell spreading
- Endothelial cells