Spontaneous and rapid reexpression of functional CXCR4 by human steady-state peripheral blood CD34+ cells.
Although only 5% of steady-state peripheral blood (PB) CD34+ cells were found to express chemokine receptor CXCR4, 45% of the cells became CXCR4+ after incubation at 37 degrees C for 4 hours. In contrast, there were no remarkable differences between PB CD34+ cells before and after the 37 degrees C incubation in their expression of selectin ligand, VLA-4, and VLA-5 or in their affinity for VCAM-1 or fibronectin. This increase in CXCR4 expression level was inhibited by the addition of brefeldin A, actinomycin D, or cycloheximide. When PB CD34+ cells with CXCR4 expression levels enhanced by a 4-hour preincubation at 37 degrees C or bone marrow (BM) CD34+ cells were exposed overnight to stromal cell-derived factor 1 (SDF-1), the expression levels of CXCR4 were greatly reduced, and when SDF-1 was removed, CXCR4 levels were thereafter up-regulated. The reexpressed CXCR4 was able to elicit integrin-dependent migration of hematopoietic progenitor cells. There was no difference in the severe combined immunodeficient mouse repopulating cell activity between PB CD34+ cells with and cells without a 37 degrees C preincubation.
Hirayama
Fumiya
F
Department of Research, Osaka Red Cross Blood Center, Osaka, Japan. fhirayam@land.linkclub.or.jp
Yamaguchi
Miki
M
Yano
Maki
M
Yasui
Kazuta
K
Horie
Yoshinori
Y
Matsumoto
Kayoko
K
Nagao
Nobuo
N
Ikebuchi
Kenji
K
Azuma
Hiroshi
H
Ikeda
Hisami
H
Tani
Yoshihiko
Y
D000818:Animals; D018952:Antigens, CD34; D001773:Blood Cells; D001854:Bone Marrow Cells; D002465:Cell Movement / Q000187:drug effects; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D019718:Receptors, CXCR4 / Q000096:biosynthesis* / Q000187:drug effects
D018952:Antigens, CD34; C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; C515256:Cxcl12 protein, mouse; D019718:Receptors, CXCR4