The inherent differentiation program of short-term hematopoietic repopulating cells changes during human ontogeny.
Human umbilical cord blood (CB) could be an attractive source of hematopoietic repopulating cells for clinical stem cell therapy because of its accessibility and low propensity for unwanted immune reaction against the host. However, CB recipients suffer from severely delayed and often chronically deficient platelet recovery of unknown cause. Here we show that human short-term repopulating cells (STRCs), which predominantly carry early hematopoietic reconstitution after transplantation, display an intrinsically fixed differentiation program in vivo that changes during ontogeny. Compared to adult sources of hematopoietic cells, CB myeloidrestricted STRC-M showed a markedly reduced megakaryocytic and erythroid cell output in the quantitative xenotransplantation of human short-term hematopoiesis in NOD/SCID-beta2m(-/-) mice. This output in vivo was not altered by pre-treating CB cells before transplantation with growth factors that effectively stimulate megakaryocytopoiesis in vitro. Moreover, injecting mice with granulocyte colony-stimulating factor did not affect the differentiation of human STRC. These findings demonstrate that the differentiation capacity of human STRCs is developmentally regulated by mechanisms inaccessible to currently available hematopoietic growth factors, and explain why thrombopoiesis is deficient in clinical CB transplantation.
Institute of Molecular Medicine and Cell Research, Albert-Ludwigs-University, Freiburg, Germany.
Marlene
M
Tacke
Claudia R
CR
Ball
Manfred
M
Schmidt
Silke
S
Klingenberg
Birgitta
B
Maurer
Sylvia
S
Fessler
Connie J
CJ
Eaves
Christof
C
von Kalle
Hanno
H
Glimm
D000818:Animals; D002454:Cell Differentiation; D005312:Fetal Blood / Q000166:cytology*; D006410:Hematopoiesis / Q000187:drug effects / Q000502:physiology; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D016513:Mice, SCID; D034061:Thrombopoiesis / Q000187:drug effects; D014183:Transplantation, Heterologous
D016298:Hematopoietic Cell Growth Factors