Hematopoietic defects in response to reduced Arhgap21

Stem Cell Res. 2018 Jan:26:17-27. doi: 10.1016/j.scr.2017.11.014. Epub 2017 Nov 23.


Arhgap21 is a member of the Rho GTPase activating protein (RhoGAP) family, which function as negative regulators of Rho GTPases. Arhgap21 has been implicated in adhesion and migration of cancer cells. However, the role of Arhgap21 has never been investigated in hematopoietic cells. Herein, we evaluated functional aspects of hematopoietic stem and progenitor cells (HSPC) using a haploinsufficient (Arhgap21+/-) mouse. Our results show that Arhgap21+/- mice have an increased frequency of phenotypic HSC, impaired ability to form progenitor colonies in vitro and decreased hematopoietic engraftment in vivo, along with a decrease in LSK cell frequency during serial bone marrow transplantation. Arhgap21+/- hematopoietic progenitor cells have impaired adhesion and enhanced mobilization of immature LSK and myeloid progenitors. Arhgap21+/- mice also exhibit reduced erythroid commitment and differentiation, which was recapitulated in human primary cells, in which knockdown of ARHGAP21 in CMP and MEP resulted in decreased erythroid commitment. Finally, we observed enhanced RhoC activity in the bone marrow cells of Arhgap21+/- mice, indicating that Arhgap21 functions in hematopoiesis may be at least partially mediated by RhoC inactivation.

Keywords: Arhgap21; Erythroid cells; Fate decision; Hematopoiesis; Hematopoietic stem and progenitor cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bone Marrow Cells / metabolism
  • Bone Marrow Cells / pathology*
  • Cell Differentiation
  • Cell Movement
  • Cell Proliferation
  • Cells, Cultured
  • Erythroid Cells / metabolism
  • Erythroid Cells / pathology
  • Fibronectins / metabolism
  • GTPase-Activating Proteins / physiology*
  • Haploinsufficiency*
  • Hematopoiesis / physiology*
  • Hematopoietic Stem Cells / metabolism
  • Hematopoietic Stem Cells / pathology*
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • rhoC GTP-Binding Protein / genetics
  • rhoC GTP-Binding Protein / metabolism*


  • ARHGAP21 protein, human
  • Fibronectins
  • GTPase-Activating Proteins
  • rhoC GTP-Binding Protein