A role of GADD45b protein in myeloid differentiation and stress response of human hematopoietic cells

Growth arrest and DNA-damage-inducible, beta (GADD45b) protein modulates stress responses in mouse myeloid cells. Recently, we demonstrated, that in patients with severe congenital neutropenia (CN) daily treatment with high doses of G-CSF stimulated C/EBPß-dependent emergency stress-induced granulopoiesis. Based on these findings, we assumed that GADD45b could play a role in the induction of granulopoiesis in CN patients. We assessed GADD45b expression levels in “arrested” promyelocytes of CN patients and surprisingly found severe downregulation of GADD45b expression in CN promyelocytes, in comparison to cyclic…