Altered in vivo and in vitro behavior of butanol-modified bone marrow cells

Cell-surface molecules, particularly glycoconjugates, appear to be involved in the in vivo homing of hematopoietic stem and progenitor cells and in their interactions with hematopoietic stromal cells. To study the role of cell-surface molecules of hematopoietic stem cells, the expression of some surface molecules was altered using n-butanol treatment. We examined the in vivo and in vitro colony-forming abilities, in vivo homing patterns, and cell-surface lectin receptor expression of butanol-treated bone marrow cells (BMC) from BDF1 mice. The butanol-treated/-modified BMC formed an increased number of significantly larger spleen colonies (CFU-S) in lethally irradiated (1050 rad) mice. The butanol-treated BM formed significantly larger in vitro granulocyte-macrophage progenitor cell colonies (CFU-C) and in vitro fibroblastic colonies (CFU-F), although the number of such colonies was not significantly altered. The homing pattern of butanol-treated BMC was studied by comparing the distribution in lethally irradiated mice of intravenously injected 51Cr-labeled butanol-treated BMC with that of untreated cells. The butanol treatment altered the in vivo homing pattern of these cells, with increased homing to liver, spleen, and bone marrow and decreased homing to thymus, lung, and mesenteric lymph nodes. Flow-cytometric analyses of butanol-treated BMC showed an increased expression of receptors for the lectins concanavalin A (conA) and wheat germ agglutinin (WGA), indicating an increased expression of mannosyl and galactosyl residues, which are known sugar moieties in hematopoietic stem/progenitor cell homing. These results indicate that cell surface modifications can influence homing and growth of transplanted BMC and that butanol treatment is a useful tool for studying the mechanisms of hematopoietic stem/progenitor cell homing in vivo and for further characterizing the molecules involved in this process.