Role of the monomeric GTPase Rho in hematopoietic progenitor cell migration and transplantation

Abstract

To investigate the role of the monomeric guanosine triphosphatase (GTPase) Rho on migration of hematopoietic progenitor cells (HPC), we employed different clostridial toxins which inhibit the Rho family of GTPases. Pretreatment with C2I‐C3, a cell‐accessible C3 transferase fusion protein that targets Rho, increased chemokinetic migration of the factor‐dependent multipotent cell line Factor Dependent Cell Paterson with mixed lineage differentiation potential (FDCP‐mix) and of primary lineage marker‐depleted HPC in vitro. In contrast, treatment with lethal toxin (LT) from Clostridium sordellii, which predominantly inactivates Rac, and with toxin B from C. difficile, which inactivates Rho, Rac and Cdc42, decreased in vitro migration. When HPC pretreated with LT or toxin B were transplanted into mice, homing to the bone marrow was impaired, whereas C2I‐C3 treatment did not alter HPC homing. However, in a competitive hematopoietic repopulation experiment in C57BL/6 mice, pretreatment of bone marrow cells with any of the inhibitors, including the Rho inhibitor C2I‐C3, resulted in suppressed donor‐type hematopoiesis. Our data indicate that whereas Rac supports HPC cell cycling, migration, short‐term homing and hematopoietic regeneration, Rho coordinates down‐regulation of HPC migration and is required for hematopoietic regeneration.

Novel Role of Ras-GTPase Activating Protein SH3 Domain-Binding Protein G3BP in Adhesion and Migration of 32D Myeloid Progenitor Cells

“…Suppression of migration, short-term homing, hematopoietic cell regeneration and cell cycling by toxin B and lethal toxin has been reported [17,18], demonstrating impairment of stem cell functions by both toxins, similar to that published for selective inhibition of Rac and Cdc42. Here, we provide evidence that the Ras GTPase activating protein SH3 domain-binding protein (G3BP) is significantly downregulated by toxin B and lethal toxin.…”

“…lethal toxin and toxin B have previously been shown to significantly impair migration, homing and engraftment of hematopoietic stem cells [17,18]. To further elucidate the molecular mechanisms of this inhibition, we treated human CD34 + TF-1 cells with lethal toxin or toxin B and analyzed changes in gene expression using high-density microarrays.…”

Rho GTPase Cdc42 is essential for human T-cell development

“…Rho GTPases have been shown to be important for migration of many cell types, including hematopoietic stem cells 14,15,[34][35][36][37] and thymocytes 21 in the mouse. We, therefore, examined the in Rho GTPases in human T-cell development haematologica | 2010; 95(3) Figure 2.…”

p210Bcr−Abl desensitizes Cdc42 GTPase signaling for SDF-1α-directed migration in chronic myeloid leukemia cells

“…In accordance, the loss of interaction between Cdc42 and its downstream effector Wiskott-Aldrich syndrome protein contributes to abnormal SDF-1a chemotaxis in T-lymphocytes of Wiskott-Aldrich syndrome patients (Haddad et al, 2001). Moreover, homing of hematopoietic progenitor cells to the BM is also impaired by pre-treatment with lethal toxin from Clostridium sordellii, which inactivates Rho family GTPases, Cdc42 and Rac1, in mice (Genth et al, 1996), whereas RhoA inactivation by Rho inhibitor, C2I-C3, does not alter the homing of hematopoietic progenitor cells in mice (Gottig et al, 2006). Herein, we raised the question whether p210…”