title: Functional and kinetic characterization of granulocyte colony-stimulating factor-primed CD34- human stem cells.
abstract: We assessed the functional properties and the kinetic status in vitro, and the engraftment potential in vivo of human haematopoietic stem cells according to the expression of CD34 antigen. Lin-CD34- and Lin-CD34+ cells were isolated from granulocyte colony-stimulating factor-primed peripheral blood (PB) cells of healthy donors. The CD34- cell fraction did not contain either clonogenic cells in semisolid culture or long-term culture initiating cells (LTC-IC). However, stroma-dependent liquid cultures and cytokines induced CD34 expression on a minority of stem cells, acquisition of clonogenic capacity and generation of LTC-IC. Significantly higher percentages of quiescent G0 cells and lower percentages of cycling G1 cells were found in Lin-CD34- cells when compared with Lin-CD34+ cells. Kinetic quiescence of Lin-CD34- cells was associated with a significantly higher expression of the negative regulators of the cell cycle, p27Kip1 and p21(cip1/waf1). Cytokine-mediated induction of CD34, in vitro, resulted in cycling of stem cells and downregulation of p27. There was a higher rate of human long-term engraftment in immunocompromised non-obese diabetic (NOD)/recombination activating gene 1null and NOD/severe combined immunodeficient-beta2microglobulin(null) mice injected with CD34+ cells. Thus, our study indicated that CD34 expression on human PB stem cells was associated with haematopoietic activity, cell-cycle recruitment and downregulation of p27Kip1 in vitro and higher engraftment capacity in vivo.
authors: Istituto di Ematologia e Oncologia Medica L. & A. Seràgnoli, University of Bologna, Bologna, Italy. rmlemoli@med.unibo.it
authors: Roberto M
authors: RM
authors: Lemoli
authors: Francesco
authors: F
authors: Bertolini
authors: Maria T
authors: MT
authors: Petrucci
authors: Chiara
authors: C
authors: Gregorj
authors: Maria R
authors: MR
authors: Ricciardi
authors: Miram
authors: M
authors: Fogli
authors: Antonio
authors: A
authors: Curti
authors: Christina
authors: C
authors: Rabascio
authors: Simona
authors: S
authors: Pandolfi
authors: Sergio
authors: S
authors: Ferrari
authors: Robin
authors: R
authors: Foá
authors: Michele
authors: M
authors: Baccarani
authors: Agostino
authors: A
authors: Tafuri
authors: Cristina
authors: C
authors: Rabascio
authors: Robin
authors: R
authors: Fo
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000276:immunology*; D002453:Cell Cycle; D002455:Cell Division; D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology*; D006801:Humans; D039041:Integrin alpha4beta1 / Q000032:analysis; D039081:Integrin alpha5beta1 / Q000032:analysis; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D019718:Receptors, CXCR4 / Q000032:analysis; D014183:Transplantation, Heterologous
chemical_list: D018952:Antigens, CD34; D039041:Integrin alpha4beta1; D039081:Integrin alpha5beta1; D019718:Receptors, CXCR4; D016179:Granulocyte Colony-Stimulating Factor