Stable long-term blood formation by stem cells in murine steady-state hematopoiesis.
Hematopoietic stem cells (HSCs) generate all mature blood cells during the whole lifespan of an individual. However, the clonal contribution of individual HSC and progenitor cells in steady-state hematopoiesis is poorly understood. To investigate the activity of HSCs under steady-state conditions, murine HSC and progenitor cells were genetically marked in vivo by integrating lentiviral vectors (LVs) encoding green fluorescent protein (GFP). Hematopoietic contribution of individual marked clones was monitored by determination of lentiviral integration sites using highly sensitive linear amplification-mediated-polymerase chain reaction. A remarkably stable small proportion of hematopoietic cells expressed GFP in LV-injected animals for up to 24 months, indicating stable marking of murine steady-state hematopoiesis. Analysis of the lentiviral integration sites revealed that multiple hematopoietic clones with both myeloid and lymphoid differentiation potential contributed to long-term hematopoiesis. In contrast to intrafemoral vector injection, intravenous administration of LV preferentially targeted short-lived progenitor cells. Myelosuppressive treatment of mice prior to LV-injection did not affect the marking efficiency. Our study represents the first continuous analysis of clonal behavior of genetically marked hematopoietic cells in an unmanipulated system, providing evidence that multiple clones are simultaneously active in murine steady-state hematopoiesis.
Department of Translational Oncology, National Center for Tumor Diseases and German Cancer Research Center, Heidelberg, Germany.
Oksana
O
Zavidij
Claudia R
CR
Ball
Friederike
F
Herbst
Felix
F
Oppel
Sylvia
S
Fessler
Manfred
M
Schmidt
Christof
C
von Kalle
Hanno
H
Glimm
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D019070:Cell Lineage; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006410:Hematopoiesis / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL