title: Rho family small GTPases control migration of hematopoietic progenitor cells into multicellular spheroids of bone marrow stroma cells.
abstract: Seeding of hematopoietic progenitor cells (HPC) into the bone marrow requires a complex interaction between cell membrane and adhesion systems and cell signaling pathways. We established a multicellular, spheroid coculture model to study HPC migration in a three-dimensional stromal environment. Here, entry of primary CD34(+) cells into stroma cell spheroids was independent of the integrins very late antigen (VLA)-4, VLA-5, lymphocyte function-associated antigen-1, and the chemokine receptor CXCR4. Experiments using a panel of bacterial toxins selectively targeting key regulators of cellular locomotion, the Rho family small GTPases Rho, Rac, and Cdc42, revealed a considerable reduction or even abrogation of TF-1 cell migration without an increase of apoptosis or impairment of proliferation. Pertussis toxin, an inhibitor of Galpha(i) proteins, showed a similar effect. In some in vitro invasion assays, phosphatidylinositol-3 kinase (PI-3K) was shown to mediate Rac- and Cdc42-induced cell motility and invasion. However, inhibition of the PI-3K pathway by LY294002 did not impair TF-1 cell migration in our three-dimensional model system.
authors.affiliation: Department of Internal Medicine III, University Hospital, J. W. Goethe University of Frankfurt, Germany. G.Bug@em.uni-frankfurt.de
authors.forename: G
authors.initials: G
authors.lastname: Bug
authors.forename: T
authors.initials: T
authors.lastname: Rossmanith
authors.forename: R
authors.initials: R
authors.lastname: Henschler
authors.forename: L A
authors.initials: LA
authors.lastname: Kunz-Schughart
authors.forename: B
authors.initials: B
authors.lastname: Schröder
authors.forename: M
authors.initials: M
authors.lastname: Kampfmann
authors.forename: M
authors.initials: M
authors.lastname: Kreutz
authors.forename: D
authors.initials: D
authors.lastname: Hoelzer
authors.forename: O G
authors.initials: OG
authors.lastname: Ottmann
mesh_terms: D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000494:pharmacology; D001854:Bone Marrow Cells / Q000502:physiology; D018821:CD18 Antigens / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects*; D016360:Clostridioides difficile; D003603:Cytotoxins / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism; D037342:Pertussis Toxin / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D019707:Receptors, Chemokine / Q000378:metabolism; D018874:Spheroids, Cellular / Q000502:physiology; D013997:Time Factors; D014407:Tumor Cells, Cultured; D020764:cdc42 GTP-Binding Protein / Q000037:antagonists & inhibitors*; D020744:rac GTP-Binding Proteins / Q000037:antagonists & inhibitors*; D020741:rho GTP-Binding Proteins / Q000037:antagonists & inhibitors*
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D018821:CD18 Antigens; D003603:Cytotoxins; D019012:Integrin beta1; D000081082:Phosphoinositide-3 Kinase Inhibitors; D019707:Receptors, Chemokine; C031815:toxB protein, Clostridium difficile; D037342:Pertussis Toxin; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins