Bone marrow homing and engraftment of human hematopoietic stem and progenitor cells is mediated by a polarized membrane domain.
Manipulation of hematopoietic stem/progenitor cells (HSPCs) ex vivo is of clinical importance for stem cell expansion and gene therapy applications. However, most cultured HSPCs are actively cycling, and show a homing and engraftment defect compared with the predominantly quiescent noncultured HSPCs. We previously showed that HSPCs make contact with osteoblasts in vitro via a polarized membrane domain enriched in adhesion molecules such as tetraspanins. Here we show that increased cell cycling during ex vivo culture of HSPCs resulted in disruption of this membrane domain, as evidenced by disruption of polarity of the tetraspanin CD82. Chemical disruption or antibody-mediated blocking of CD82 on noncultured HSPCs resulted in decreased stromal cell adhesion, homing, and engraftment in nonobese diabetic/severe combined immunodeficiency IL-2γ(null) (NSG) mice compared with HSPCs with an intact domain. Most leukemic blasts were actively cycling and correspondingly displayed a loss of domain polarity and decreased homing in NSG mice compared with normal HSPCs. We conclude that quiescent cells, unlike actively cycling cells, display a polarized membrane domain enriched in tetraspanins that mediates homing and engraftment, providing a mechanistic explanation for the homing/engraftment defect of cycling cells and a potential new therapeutic target to enhance engraftment.
Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
Andre
A
Larochelle
Jennifer M
JM
Gillette
Ronan
R
Desmond
Brian
B
Ichwan
Amy
A
Cantilena
Alexandra
A
Cerf
A John
AJ
Barrett
Alan S
AS
Wayne
Jennifer
J
Lippincott-Schwartz
Cynthia E
CE
Dunbar
D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism; D001853:Bone Marrow / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D053631:Interleukin Receptor Common gamma Subunit / Q000172:deficiency / Q000235:genetics; D051861:Kangai-1 Protein / Q000378:metabolism; D007938:Leukemia / Q000378:metabolism / Q000473:pathology; D021962:Membrane Microdomains / Q000378:metabolism*; D051379:Mice; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D016513:Mice, SCID; D018613:Microscopy, Confocal; D019718:Receptors, CXCR4 / Q000378:metabolism; D059470:Tetraspanins / Q000378:metabolism; D014183:Transplantation, Heterologous
D018952:Antigens, CD34; C527276:CXCR4 protein, human; D016207:Cytokines; C507942:Il2rg protein, mouse; D053631:Interleukin Receptor Common gamma Subunit; D051861:Kangai-1 Protein; D019718:Receptors, CXCR4; D059470:Tetraspanins