Homing and engraftment potential of Sca-1+lin cells fractionated on the basis of adhesion molecule expression and position in cell cycle

CM Orschell-Traycoff, K Hiatt… - Blood, The Journal …, 2000 - ashpublications.org
CM Orschell-Traycoff, K Hiatt, RN Dagher, S Rice, MC Yoder, EF Srour
Blood, The Journal of the American Society of Hematology, 2000ashpublications.org
Engraftment potential of hematopoietic stem cells (HSCs) is likely to be dependent on
several factors including expression of certain adhesion molecules (AMs) and degree of
mitotic quiescence. The authors investigated the functional properties and engraftment
potential of Sca-1+ lin− cells subfractionated on the basis of expression, or lack thereof, of
CD11a, CD43, CD49d, CD49e, or CD62L and correlated that expression with cell cycle
status and proliferative potential of engrafting fractions. Donor-derived chimerism in mice …
Abstract
Engraftment potential of hematopoietic stem cells (HSCs) is likely to be dependent on several factors including expression of certain adhesion molecules (AMs) and degree of mitotic quiescence. The authors investigated the functional properties and engraftment potential of Sca-1+lin cells subfractionated on the basis of expression, or lack thereof, of CD11a, CD43, CD49d, CD49e, or CD62L and correlated that expression with cell cycle status and proliferative potential of engrafting fractions. Donor-derived chimerism in mice receiving CD49e+ or CD43+ Sca-1+lin cells was greater than that in mice receiving cells lacking these 2 markers, while Sca-1+lin cells positive for CD11a and CD62L and bright for CD49d expression mediated minimal engraftment. AM phenotypes enriched for engraftment potential contained the majority of high proliferative potential–colony forming cells, low proliferative potential–colony forming cells, and cells providing rapid in vitro expansion. Cell cycle analysis of AM subpopulations revealed that, regardless of their bone marrow repopulating potential, Sca-1+lin AM cells contained a higher percentage of cells in G0/G1 than their AM+ counterparts. Interestingly, engrafting phenotypes, regardless of the status of their AM expression, were quicker to exit G0/G1 following in vitro cytokine stimulation than their opposing phenotypes. When engrafting phenotypes of Sca-1+lin AM+ or AMcells were further fractionated by Hoechst 33342 into G0/G1 or S/G2+M, cells providing long-term engraftment were predominantly contained within the quiescent fraction. These results define a theoretical phenotype of a Sca-1+lin engrafting cell as one that is mitotically quiescent, CD43+, CD49e+, CD11a, CD49ddim, and CD62L. Furthermore, these data suggest that kinetics of in vitro proliferation may be a good predictor of engraftment potential of candidate populations of HSCs.
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