Human marrow stromal precursors are alpha 1 integrin subunit-positive.
In this work we studied the expression of adhesion molecules on primate human and non-human marrow stromal cells (primary cultures and lines) and on human CD34(+) hematopoietic normal and leukemic precursors. Differential expression of alpha1 integrin subunit was observed, since this molecule was intensely expressed by marrow stroma but not detected on CD34(+) cells. We used this difference to select, in fresh bone marrow samples, alpha 1-positive cells. We found that all stromal precursors giving rise to colony-forming units-fibroblasts (CFU-F) were present in the alpha 1-positive fraction. No colonies were detected in the alpha 1-negative fraction even after 2 weeks of culture. Phenotypic studies of stromal cells derived from alpha1-positive cells and grown in long-term marrow culture indicated that these cells were similar to stromal cells from primary cultures. We also observed early upregulation of alpha 4 and alpha 2 integrin subunits in cultures derived from alpha1-positive cells with maximal expression by day 10 (26 and 51%, respectively) preceding a gradual decline to low to nil values at day 30 (4.5 and 12%). These data indicate that alpha 1 integrin subunit is a marker for both mature stromal cells and stromal precursors, while alpha 2 and alpha 4 integrin subunits are expressed primarily by immature cells.
Etablissement de Transfusion Sanguine de Franche-Comté, Besançon, France.
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Deschaseaux
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Charbord
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D000954:Antigens, Surface / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D039423:Integrin alpha1; D007938:Leukemia / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D010641:Phenotype; D011323:Primates
D015703:Antigens, CD; D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D039423:Integrin alpha1