Laminin isoform-specific promotion of adhesion and migration of human bone marrow progenitor cells

Here they studied human bone marrow cell adhesion to laminin-511/521, laminin-411, laminin-111, and fibronectin. About 35% to 40% of CD34⁺ and CD34⁺CD38^– stem and progenitor cells adhered to laminin-511/521, and 45% to 50% adhered to fibronectin, whereas they adhered less to laminin-411 and laminin-111. Adhesion of CD34⁺CD38^– cells to laminin-511/521 was maximal without integrin activation, whereas adhesion to other proteins was dependent on protein kinase C activation. Integrin a6 chain expressed on most CD34+ and CD34+CD38-cells. Laminin-511/521 was highly adhesive to lineage-committed myelomonocytic and erythroid progenitor cells and most lymphoid and myeloid cell lines studied, whereas fibronectin and laminin-411 were less adhesive. Laminin-511/521was a ubiquitous adhesive protein for differentiated precursors of both B-lymphocytic, erythroid, megakaryocytic, and myelomonocytic cell lineages, whereas adhesion to laminin-411 and laminin-111 was restricted to a few cell lines. CD34⁺ cell migration was greatly enhanced through membranes coated with Laminin-511/521 and laminin-411. Our findings raise the possibility that a4 and a5 laminins are involved in mobilization and homing of hematopoietic progenitor cells.