Abstract
Hematopoietic stem cell homing and engraftment require several adhesion interactions, which are not fully understood. Engraftment of nonobese/severe combined immunodeficiency (NOD/SCID) mice by human stem cells is dependent on the major integrins very late activation antigen-4 (VLA-4); VLA-5; and to a lesser degree, lymphocyte function associated antigen-1 (LFA-1). Treatment of human CD34(+) cells with antibodies to either VLA-4 or VLA-5 prevented engraftment, and treatment with anti-LFA-1 antibodies significantly reduced the levels of engraftment. Activation of CD34(+) cells, which bear the chemokine receptor CXCR4, with stromal derived factor 1 (SDF-1) led to firm adhesion and transendothelial migration, which was dependent on LFA-1/ICAM-1 (intracellular adhesion molecule-1) and VLA-4/VCAM-1 (vascular adhesion molecule-1). Furthermore, SDF-1-induced polarization and extravasation of CD34(+)/CXCR4(+) cells through the extracellular matrix underlining the endothelium was dependent on both VLA-4 and VLA-5. Our results demonstrate that repopulating human stem cells functionally express LFA-1, VLA-4, and VLA-5. Furthermore, this study implies a novel approach to further advance clinical transplantation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antibodies / pharmacology
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Antigens, CD34
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Cell Adhesion
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Cells, Cultured
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Chemokine CXCL12
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Chemokines, CXC / pharmacology*
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Chemotaxis
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Endothelium, Vascular / physiology*
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Fetal Blood / cytology
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Hematopoietic Stem Cell Transplantation*
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Hematopoietic Stem Cells / drug effects
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Hematopoietic Stem Cells / immunology
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Hematopoietic Stem Cells / physiology*
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Humans
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Infant, Newborn
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Integrin alpha4beta1
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Integrin beta1 / physiology
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Integrins / antagonists & inhibitors
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Integrins / physiology*
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Lymphocyte Function-Associated Antigen-1 / immunology
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Lymphocyte Function-Associated Antigen-1 / physiology*
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Mice
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Mice, Inbred NOD
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Mice, SCID
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Models, Biological
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Receptors, Fibronectin / antagonists & inhibitors
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Receptors, Fibronectin / physiology*
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Receptors, Lymphocyte Homing / antagonists & inhibitors
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Receptors, Lymphocyte Homing / physiology*
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Stromal Cells / physiology*
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Transplantation, Heterologous / immunology*
Substances
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Antibodies
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Antigens, CD34
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CXCL12 protein, human
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Chemokine CXCL12
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Chemokines, CXC
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Cxcl12 protein, mouse
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Integrin alpha4beta1
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Integrin beta1
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Integrins
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Lymphocyte Function-Associated Antigen-1
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Receptors, Fibronectin
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Receptors, Lymphocyte Homing