Human fibrotic bone marrow (BM) stroma has been shown to contain α-smooth muscle actin (α-SMA)-positive cells. These closely resemble myofibroblasts that were described in other fibrotic tissues. We studied the expression of α-SMA in a series of murine BM-derived stromal cell lines to investigate the cellular origin and functional significance of myofibroblast-like cells in hematopoietic tissues. Although these cell lines differed in their biologic properties, most of them expressed á-SMA under certain conditions. Cells expressing α-SMA constituted a minor population in post-confluent, growth-arrested cultures. However, the incidence of cells expressing α-SMA increased significantly when cultures were transferred to nonconfluent conditions. A similar increase in α-SMA-positive cells occurred after a strip of cells was scraped away from the confluent cell layer; the cells of the affected area acquired α-SMA-positive contractile phenotype. The relationship between α-SMA expression and hematopoietic activity was studied using a cloned cell line of BM origin (14F1.1). The ability of these endothelial-adipocyte cells to support hematopoiesis in vitro was maximal under confluent conditions, whereas their expression of α-SMA under such conditions was residual. Moreover, in long-term BM cultures supported by confluent 14F1.1 cells, stromal areas associated with proliferating hematopoietic precursors, known as "cobblestone areas," were devoid of α-SMA-positive cells. These observations suggest that the expression of α-SMA is reversible and inversely related to hematopoietic activity. © 1991 by The American Society of Hematology.
CITATION STYLE
Peled, A., Zipori, D., Abramsky, O., Ovadia, H., & Shezen, E. (1991). Expression of α-smooth muscle actin in murine bone marrow stromal cells. Blood, 78(2), 304–309. https://doi.org/10.1182/blood.v78.2.304.bloodjournal782304
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