title: Vinculin is indispensable for repopulation by hematopoietic stem cells, independent of integrin function.
abstract: Vinculin is a highly conserved actin-binding protein that is localized in integrin-mediated focal adhesion complexes. Although critical roles have been proposed for integrins in hematopoietic stem cell (HSC) function, little is known about the involvement of intracellular focal adhesion proteins in HSC functions. This study showed that the ability of c-Kit(+)Sca1(+)Lin(-) HSCs to support reconstitution of hematopoiesis after competitive transplantation was severely impaired by lentiviral transduction with short hairpin RNA sequences for vinculin. The potential of these HSCs to differentiate into granulocytic and monocytic lineages, to migrate toward stromal cell-derived factor 1α, and to home to the bone marrow in vivo were not inhibited by the loss of vinculin. However, the capacities to form long term culture-initiating cells and cobblestone-like areas were abolished in vinculin-silenced c-Kit(+)Sca1(+)Lin(-) HSCs. In contrast, adhesion to the extracellular matrix was inhibited by silencing of talin-1, but not of vinculin. Whole body in vivo luminescence analyses to detect transduced HSCs confirmed the role of vinculin in long term HSC reconstitution. Our results suggest that vinculin is an indispensable factor determining HSC repopulation capacity, independent of integrin functions.
authors.affiliation: Research Division of Cell and Molecular Medicine, Center for Molecular Medicine, Jichi Medical University, Tochigi 329-0498, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Ohmori
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kashiwakura
authors.forename: Akira
authors.initials: A
authors.lastname: Ishiwata
authors.forename: Seiji
authors.initials: S
authors.lastname: Madoiwa
authors.forename: Jun
authors.initials: J
authors.lastname: Mimuro
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Furukawa
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Sakata
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D054377:Chemokine CXCL12 / Q000235:genetics / Q000378:metabolism; D005109:Extracellular Matrix / Q000235:genetics / Q000378:metabolism; D020868:Gene Silencing; D006410:Hematopoiesis / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D016023:Integrins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D016608:Talin / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D016596:Vinculin / Q000235:genetics / Q000378:metabolism*
chemical_list: D054377:Chemokine CXCL12; C515256:Cxcl12 protein, mouse; D016023:Integrins; D016608:Talin; C496077:Tln1 protein, mouse; D016596:Vinculin