Genetically defining the mechanism of Puma- and Bim-induced apoptosis

• Published in: Cell death and differentiation 2012-04, Vol.19 (4), p.642-649
• Main Authors: Garrison, S P, Phillips, D C, Jeffers, J R, Chipuk, J E, Parsons, M J, Rehg, J E, Opferman, J T, Green, D R, Zambetti, G P
• Format: Article
• Language: English
• Subjects: Anemia, Aplastic; Animal models; Animals; Apoptosis; Apoptosis Regulatory Proteins - genetics; Apoptosis Regulatory Proteins - metabolism; BAK protein; Bax protein; Bcl-2 protein; bcl-2-Associated X Protein - genetics; bcl-2-Associated X Protein - metabolism; Bcl-2-Like Protein 11; BID protein; BIM protein; Biochemical analysis; Biochemistry; Biomedical and Life Sciences; Biphenyl Compounds - pharmacology; Bone marrow; Bone Marrow Diseases; Cancer therapies; Carboplatin; Cell Biology; Cell Cycle Analysis; Cell death; Cell Survival - genetics; Cooperation; Cytochrome; Cytochrome c; Cytochromes c - genetics; Cytochromes c - metabolism; Cytokines; DNA Damage; Gastrointestinal tract; Gene Deletion; Growth factors; Hemoglobinuria, Paroxysmal - genetics; Hemoglobinuria, Paroxysmal - metabolism; Hemoglobinuria, Paroxysmal - pathology; Ionizing radiation; Life Sciences; Lymphoma; Mast cells; Mast Cells - metabolism; Mast Cells - pathology; Medical research; Membrane permeability; Membrane Proteins - genetics; Membrane Proteins - metabolism; Mice; Mice, Knockout; Mitochondria; Mitochondrial Membranes - metabolism; Mitochondrial Membranes - pathology; Nitrophenols - pharmacology; Original Paper; Outer membranes; p53 protein; Permeability; Piperazines - pharmacology; Proteins; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - metabolism; Radiation; Starvation; Stem Cells; Sulfonamides - pharmacology; Toxicity; Tumor Suppressor Protein p53 - genetics; Tumor Suppressor Protein p53 - metabolism; Tumor Suppressor Proteins - genetics; Tumor Suppressor Proteins - metabolism; Tumors
• ISSN: 1350-9047; 1476-5403
• DOI: 10.1038/cdd.2011.136

Using genetically modified mouse models, we report here that p53 upregulated modulator of apoptosis (Puma) and Bcl-2 interacting mediator of cell death (Bim), two pro-apoptotic members of the B-cell lymphoma protein-2 (Bcl-2) family of proteins, cooperate in causing bone marrow and gastrointestinal tract toxicity in response to chemo and radiation therapy. Deletion of both Puma and Bim provides long-term survival without evidence of increased tumor susceptibility following a lethal challenge of carboplatin and ionizing radiation. Consistent with these in vivo findings, studies of primary mast cells demonstrated that the loss of Puma and Bim confers complete protection from cytokine starvation and DNA damage, similar to that observed for Bax/Bak double knockout cells. Biochemical analyses demonstrated an essential role for either Puma or Bim to activate Bax, thereby leading to mitochondrial outer membrane permeability, cytochrome c release and apoptosis. Treatment of cytokine-deprived cells with ABT-737, a BH3 mimetic, demonstrated that Puma is sufficient to activate Bax even in the absence of all other known direct activators, including Bim, Bid and p53. Collectively, our results identify Puma and Bim as key mediators of DNA damage-induced bone marrow failure and provide mechanistic insight into how BH3-only proteins trigger cell death.