Cell cycling status of human cord blood CD34+ cells during ex vivo expansion is related to the level of very late antigen expression.
Very late antigen-4 (VLA-4), which binds to the extracellular matrix protein fibronectin, is an integrin molecule known to be modulated during mobilization of CD34+ cells, and to be involved in signaling the mobilization stimuli. On the hypothesis that cell cycling status might be different depending on the level of VLA-4 expression, we investigated the DNA contents of human cord blood CD34+ cells during ex vivo expansion by recombinant human thrombopoietin and flt3-ligand with simultaneous measurement of surface VLA-4 at the 1st and 4th week. During this ex vivo expansion, expression of VLA-4 increased and almost all cells became VLA-4+ until the 4th day of culture. Expression of VLA-4 was maintained in the major population of the cultured cells until the 4th week. The cells in S/G2/M phase were greater in number in VLA-4 high fraction than in VLA-4 low fraction (n=4, p<.001). Furthermore, the fraction of cells in S/G2/M phase increased as the expression of VLA-4 became higher. These results suggest that cord blood CD34+ cells expressing high levels of VLA-4 have more proliferative activities.
Seoh
J Y
JY
Department of Microbiology, Medical Research Center, College of Medicine, Ewha Womans University, Seoul, Korea.
Park
H Y
HY
Chung
W S
WS
Kim
S C
SC
Hahn
M J
MJ
Kim
K H
KH
Shin
H Y
HY
Ahn
H S
HS
Park
K W
KW
Ryu
K H
KH
D018952:Antigens, CD34 / Q000032:analysis*; D002478:Cells, Cultured; D004247:DNA / Q000032:analysis; D005312:Fetal Blood / Q000166:cytology*; D016195:G2 Phase; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D006801:Humans; D016130:Immunophenotyping; D007231:Infant, Newborn; D039041:Integrin alpha4beta1; D016023:Integrins / Q000032:analysis*; D016201:Receptors, Lymphocyte Homing / Q000032:analysis*; D016196:S Phase
D018952:Antigens, CD34; D039041:Integrin alpha4beta1; D016023:Integrins; D016201:Receptors, Lymphocyte Homing; D004247:DNA