title: Fibronectin and VLA-4 in haematopoietic stem cell-microenvironment interactions.
abstract: The self-renewal and differentiation of haematopoietic stem cells occurs in vivo and in vitro in direct contact with cells making up the haematopoietic microenvironment. In this study we used adhesive ligands and blocking antibodies to identify stromal cell-derived extracellular matrix proteins involved in promoting attachment of murine haematopoietic stem cells. Here we report that day-12 colony-forming-unit spleen (CFU-S12)5 cells and reconstituting haematopoietic stem cells attach to the C-terminal, heparin-binding fragment of fibronectin by recognizing the CS-1 peptide of the alternatively spliced non-type III connecting segment (IIICS) of human plasma fibronectin. Furthermore, CFU-S12 stem cells express the alpha 4 subunit of the VLA-4 integrin receptor, which is known to be a receptor for the CS-1 sequence, and monoclonal antibodies against the integrin alpha 4 subunit of VLA-4 block adhesion of CFU-S12 stem cells to plates coated with the C-terminal fibronectin fragment. Finally, polyclonal antibodies against the integrin beta 1 subunit of VLA-4 inhibit the formation of CFU-S12-derived spleen colonies and medullary haematopoiesis in vivo following intravenous infusion of antibody-treated bone marrow cells.
authors.affiliation: Howard Hughes Medical Institute, Boston, Massachusetts.
authors.forename: D A
authors.initials: DA
authors.lastname: Williams
authors.forename: M
authors.initials: M
authors.lastname: Rios
authors.forename: C
authors.initials: C
authors.lastname: Stephens
authors.forename: V P
authors.initials: VP
authors.lastname: Patel
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D002448:Cell Adhesion; D005109:Extracellular Matrix / Q000502:physiology*; D005260:Female; D005353:Fibronectins / Q000276:immunology / Q000378:metabolism*; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006493:Heparin / Q000378:metabolism; D007116:Immunization, Passive; D039001:Integrin alpha Chains; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism; D016029:Receptors, Very Late Antigen / Q000276:immunology / Q000378:metabolism*; D013154:Spleen / Q000166:cytology
chemical_list: C063493:CDw49d; D005353:Fibronectins; D039001:Integrin alpha Chains; D010446:Peptide Fragments; D016029:Receptors, Very Late Antigen; D006493:Heparin