Flk-2 is a marker in hematopoietic stem cell differentiation: a simple method to isolate long-term stem cells

JL Christensen, IL Weissman - Proceedings of the National …, 2001 - National Acad Sciences
JL Christensen, IL Weissman
Proceedings of the National Academy of Sciences, 2001National Acad Sciences
Clonogenic multipotent mouse hematopoietic stem cells (HSCs) and progenitor cells are
contained within the c-kit+ (K) lineage−/lo (L) Sca-1+(S) population of hematopoietic cells;
long-term (LT) and short-term (ST) HSCs are Thy-1.1 lo. c-kit is a member of the receptor
tyrosine kinase family, a class of receptors that are important in the proliferation and
differentiation of hematopoietic cells. To establish whether the Flk-2/Flt3 receptor tyrosine
kinase was expressed on the most primitive LT-HSCs, we sorted highly purified multipotent …
Clonogenic multipotent mouse hematopoietic stem cells (HSCs) and progenitor cells are contained within the c-kit+ (K) lineage−/lo (L) Sca-1+ (S) population of hematopoietic cells; long-term (LT) and short-term (ST) HSCs are Thy-1.1lo. c-kit is a member of the receptor tyrosine kinase family, a class of receptors that are important in the proliferation and differentiation of hematopoietic cells. To establish whether the Flk-2/Flt3 receptor tyrosine kinase was expressed on the most primitive LT-HSCs, we sorted highly purified multipotent stem and progenitor cells on the basis of Flk-2 surface expression and used them in competitive reconstitution assays. Low numbers of Flk-2 HSCs gave rise to long-term multilineage reconstitution in the majority of recipients, whereas the transfer of Flk-2+ multipotent cells resulted in mostly short-term multilineage reconstitution. The KLS subset of adult mouse bone marrow was analyzed for Flk-2 and Thy-1.1 expression. Three phenotypically and functionally distinct populations were isolated: Thylo Flk-2 (LT-HSCs), Thylo Flk-2+ (ST-HSCs), and Thy Flk-2+ multipotent progenitors. The loss of Thy-1.1 and gain of Flk-2 expression marks the loss of self-renewal in HSC maturation. The addition of Flk-2 antibody to the lineage mix allows direct isolation of LT-HSC from adult bone marrow as c-kit+ lin Sca-1+ Flk-2 from many strains of mice. Fetal liver HSCs are contained within Flk-2 and Flk-2+ KTLS cells.
National Acad Sciences