| Autor: |
Kerst, J. Martijn, Sanders, Joost B., Slaper-Cortenbach, Ineke C.M., Doorakkers, Marc Ch., Hooibrink, Berend, van Oers, Rien H.J., von dem Borne, Albert E.G.Kr., van der Schoot, C. Ellen |
| Zdroj: |
Blood; January 1993, Vol. 81 Issue: 2 p344-351, 8p |
| Abstrakt: |
To study the receptors involved in the interaction between extracellular matrix proteins and hematopoietic progenitor cells, we analyzed the expression of β1 integrins on CD34+bone marrow cells by means of immunoflowcytometry. α4β1 and α5β1 were expressed, whereas α1β1, α2β1, α3β1, α6β1, and αvβ1 were virtually absent. Furthermore, we assessed the α4 and α5 expression on committed myeloid progenitor cells. These colony-forming cells were detected in the α4 dull fraction and the α5 dull fraction. During myeloid differentiation, both in vivo and in vitro, a differential expression of α4β1 and α5β1 was observed. α5β1 was found to be lost at the myelocytic-metamyelocytic stage, before the loss of α4β1, at the band stage. Functional studies showed no binding of erythroid progenitor-depleted, CD34+bone marrow cells to fibronectin. However, protein kinase C activation strongly induced fibronectin binding (68% of the cells). Inhibition experiments with specific antibodies and peptides showed the binding to be mediated by both α4β1 and α5β1. Also, colony-forming cells of granulocytes and macrophages were demonstrated to adhere to fibronectin in an activation-dependent way. During granulocyte colony-stimulating factor-induced in vitro maturation, the activation-dependent fibronectin binding capacity is gradually lost. We conclude that: (1) CD34+bone marrow cells express α4β1 and α5β1; (2) the expression of α4β1 and α5β1 is differentially expressed during myeloid differentiation; and (3) binding of CD34+bone marrow cells to fibronectin is activation dependent. |
| Databáze: |
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