[Cell cycle-dependent change of the adhesive character of CD34+ progenitor cells and their VLA-4 expression].
We identified the cell cycle status of CD34+ cells of steady-state bone marrow (BM) and peripheral blood (PB) obtained from healthy volunteers, and those of BM and apheresis PB samples collected from donors who had been administered granulocyte colony-stimulating factor (G-CSF). Regardless of whether G-CSF treatment was undergone, more than 10% of CD34+ cells in the BM was in the S + G2/M phase. In contrast, less than 2% of CD34+ cells in the PB was cycling. After co-culturing BM CD34+ cells with a monolayer of the stromal cell line MS-5 for 1 hour, some cells adhered to the stroma. The percentage of cells in the S + G2/M phase among these adherent cells was higher than that among the non-adherent cells. Flow cytometric analysis revealed that CD34+ cells in mobilized PB expressed less VLA-4 than those in BM and that in in vitro-cultured non-adherent cells exhibited a lower level of VLA-4 expression than adherent cells. In addition, CD34+ cells in the G0/G1 phase expressed lower levels of VLA-4 than those in the S + G2/M phase. These findings suggested that the reduced expression of adhesion molecules such as VLA-4 by the progenitor cells in the G0/G1 phase of the cell cycle result in the release of progenitor cells from the hematopoietic microenvironment to peripheral blood.
Yamaguchi
M
M
Hokkaido Red Cross Blood Center, Sapporo.
Ikebuchi
K
K
Hirayama
F
F
Sato
N
N
Sekiguchi
S
S
D018952:Antigens, CD34 / Q000378:metabolism*; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology*; D006801:Humans; D039041:Integrin alpha4beta1; D016023:Integrins / Q000378:metabolism*; D016201:Receptors, Lymphocyte Homing / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism
D018952:Antigens, CD34; D015815:Cell Adhesion Molecules; D039041:Integrin alpha4beta1; D016023:Integrins; D016201:Receptors, Lymphocyte Homing