Granulocyte Colony-Stimulating Factor Prior to Nonmyeloablative Irradiation Decreases Murine Host Hematopoietic Stem Cell Function and Increases Engraftment of Donor Marrow Cells

Abstract

The use of nonmyeloablative conditioning prior to bone marrow transplantation is an important component of transplantation-based therapies for nonmalignant blood diseases. In this study, treatment of recipient mice with granulocyte colony-stimulating factor (G-CSF) prior to low-dose total body irradiation (LD-TBI) enhanced long-term engraftment of freshly isolated congenic marrow 1.5- to 2-fold more than treatment with LD-TBI alone. This combined regimen was also evaluated in a mouse model of X-linked chronic granulomatous disease (X-CGD), where neutrophils have a defective NADPH oxidase due to genetic deletion of the gp91(phox) subunit. Long-term engraftment of male X-CGD bone marrow cells cultured ex vivo for retroviral transduction of gp91(phox) was enhanced by approximately 40% when female X-CGD recipients were pretreated with G-CSF prior to 300 cGy. These data confirm that sequential treatment with G-CSF and LD-TBI prior to transplantation increases long-term engraftment of donor marrow, and they extend this approach to transplantation of murine donor marrow cultured ex vivo for gene transfer. Additional studies showed that the administration of G-CSF prior to LD-TBI did not alter early homing of donor marrow cells. However, the combined regimen significantly decreased the content of long-term repopulating cells in recipient marrow compared with LD-TBI alone, as assessed in competitive assays, which may contribute to the enhanced engraftment of donor marrow cells. Disclosure of potential conflicts of interest is found at the end of this article.

A novel competitive repopulation strategy to quantitate engraftment of ex vivo manipulated murine marrow cells in submyeloablated hosts

“…These data demonstrate that lin − cells transduced in this manner engraft less well in submyeloablated hosts than do fresh lin − cells. Furthermore, since a modest increase in conditioning radiation led to a ≥11-fold increase in donor chimerism, these data confirm that engraftment is determined in part by the degree of host HSC impairment [17,24,27].…”

“…We used SCF and IL-6 in both transduction protocols in this work because this combination is known to enhance HSC self-renewal and mediates efficient retroviral transduction [30], and because of our past experience with this cocktail [17,24,27]. Of note, Li et al [18] and Bryder et al [29] used different cytokine cocktails for their work; numerous other cocktails have also been reported to maintain and/or expand HSC function in culture [31,32] or augment retroviral transduction [18,21,33,34].…”

L-selectin mechanochemistry restricts neutrophil priming in vivo

“…Flow cytometric analysis of respiratory burst and phagocytosis in neutrophils was performed as described54 with some modifications. For respiratory burst induced by PMA, 100 μl of blood was lysed, washed and resuspended in 500 μl HBSS − /EDTA/HSA.…”

Novel interferon-based pre-transplantation conditioning in the treatment of a congenital metabolic disorder

“…Recently, granulocyte colony-stimulating factor was also reported to be useful for pre-transplant conditioning, but only when combined with LD-TBI. 22 In addition, blocking the SCF/c-Kit interaction by administering the mAb Ack2 permits substantial donor HSC repopulation in immunodeficient mice without LD-TBI, 23 but HSC repopulation in immunocompetent mice requires LD-TBI. 24 Therefore, it is worth emphasizing that our poly(I:C) and 5-FU conditioning can significantly enhance the engraftment of HSClevel donor-derived cells in the absence of TBI or alkylating drugs.…”