title: Dock2 participates in bone marrow lympho-hematopoiesis.
abstract: Dock2 has been shown to be indispensable for chemotaxis of mature lymphocytes as a critical Rac activator. However, the functional expression of Dock2 in immature hematopoietic cells is unclear. In this study, we demonstrate that Dock2 is broadly expressed in bone marrow (BM) hematopoietic compartment, including hematopoietic stem/progenitor cell (HSC/HPC) fraction. Response of Dock2-/- HPCs to CXCL12 in chemotaxis and actin polymerization in vitro was impaired, although alpha4 integrin activation by CXCL12 was not altered. Myelosuppressive stress on HSCs in vivo, such as consecutive 5-FU administration and serial bone marrow transplantation, did not show hematopoietic defect in Dock2-/- mice. Long-term engraftment of transplanted Dock2-/- BM cells was severely impaired in competitive reconstitution. However, this was not intrinsic to HSCs but originated from the defective competition of Dock2-/- lymphoid precursors. These results suggest that Dock2 plays a significant role in BM lymphopoiesis, but is dispensable for HSC engraftment and self-renewal.
authors.affiliation: Hematology, Oncology, and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kikuchi
authors.forename: Shiro
authors.initials: S
authors.lastname: Kubonishi
authors.forename: Misako
authors.initials: M
authors.lastname: Shibakura
authors.forename: Noriko
authors.initials: N
authors.lastname: Namba
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Matsui
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Fukui
authors.forename: Mitsune
authors.initials: M
authors.lastname: Tanimoto
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Katayama
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001853:Bone Marrow / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D016026:Bone Marrow Transplantation / Q000473:pathology; D054377:Chemokine CXCL12 / Q000494:pharmacology; D002633:Chemotaxis / Q000502:physiology; D005472:Fluorouracil / Q000494:pharmacology; D020690:GTPase-Activating Proteins / Q000494:pharmacology*; D020662:Guanine Nucleotide Exchange Factors; D006410:Hematopoiesis / Q000187:drug effects* / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D007951:Leukemia, Myeloid / Q000378:metabolism / Q000473:pathology; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D019718:Receptors, CXCR4 / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D013997:Time Factors
chemical_list: D000199:Actins; D054377:Chemokine CXCL12; C471356:DOCK2 protein, mouse; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D019718:Receptors, CXCR4; D005472:Fluorouracil