Essential role for the BH3-only protein Bim but redundant roles for Bax, Bcl-2, and Bcl-w in the control of granulocyte survival

Villunger, A; Scott, C; Bouillet, P; Strasser, A

Author(s): Villunger, A; Scott, C; Bouillet, P; Strasser, A;
Details: Publication Year 2003-03-15,Volume 101,Issue #6,Page 2393-2400
Journal Title: BLOOD
Publication Type: Journal Article
Abstract: Programmed cell death of granulocytes is one of the mechanisms that limit inflammatory responses. Members of the Bcl-2 protein family are essential regulators of apoptosis induced by growth factor withdrawal or cytotoxic stress. We have used gene-targeted and transgenic mice to investigate the roles of the prosurvival molecules Bcl-2 and Bcl-w and their proapoptotic relatives Bax and Bim in spontaneous and stress-induced apoptosis of granulocytes from bone marrow or the peritoneum. Bim deficiency, like Bcl-2 overexpression, rendered granulocytes resistant to cytokine withdrawal and cytotoxic drugs, but absence of Bax alone had no protective effect. Loss of Bcl-2 or Bcl-w did not increase the sensitivity of granulocytes to any of these apoptotic stimuli, but Bcl-2 was essential for the in vitro survival of myeloid progenitors under conditions of cytokine withdrawal where cell death was mediated, in part, by Bim. Granulocyte colony-stimulating factor (G-CSF), a key survival factor for granulocytes, enhanced viability of cells lacking bcl-2, bcl-w, bax, or bim, indicating that none of these genes alone is the essential target of this cytokine's prosurvival function. Expression analysis of proapoptotic Bcl-2 family members in granulocytes revealed that the BH3-only protein Bmf is induced upon cytokine withdrawal. These results indicate that the BH3-only protein Bim and possibly also Bmf are critical initiators of spontaneous and drug-induced apoptosis of granulocytes, whereas Bcl-2, Bcl-w, and Bax act in a redundant manner in regulating granulocyte survival and death, respectively.
Publisher: AMER SOC HEMATOLOGY
Keywords: COLONY-STIMULATING FACTOR; FAMILY MEMBER BIM; CELL-SURVIVAL; MYELOID DIFFERENTIATION; NEUTROPHIL APOPTOSIS; MOTOR COMPLEX; FAS LIGAND; EXPRESSION; DEATH; MICE
Publisher's Version: https://doi.org/10.1182/blood-2002-07-2132
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 2003-03-15 12:00:00