title: BH3-only proteins Puma and Bim are rate-limiting for gamma-radiation- and glucocorticoid-induced apoptosis of lymphoid cells in vivo.
abstract: Numerous p53 target genes have been implicated in DNA damage-induced apoptosis signaling, but proapoptotic Bcl-2 (B-cell leukemia 2) family members of the BH3 (Bcl-2 homolog region [BH] 3)-only subgroup appear to play the critical initiating role. In various types of cultured cells, 3 BH3-only proteins, namely Puma (p53 up-regulated modulator of apoptosis), Noxa, and Bim (Bcl-2 interacting mediator of cell death), have been shown to initiate p53-dependent as well as p53-independent apoptosis in response to DNA damage and treatment with anticancer drugs or glucocorticoids. In particular, the absence of Puma or Bim renders thymocytes and mature lymphocytes refractory to varying degrees to death induced in vitro by growth factor withdrawal, DNA damage, or glucocorticoids. To assess the in vivo relevance of these findings, we subjected mice lacking Puma, Noxa, or Bim to whole-body gamma-radiation or the glucocorticoid dexamethasone and compared lymphocyte survival with that in wild-type and BCL2-transgenic mice. Absence of Puma or Bcl-2 overexpression efficiently protected diverse types of lymphocytes from the effects of gamma-radiation in vivo, and loss of Bim provided lower but significant protection in most lymphocytes, whereas Noxa deficiency had no impact. Furthermore, both Puma and Bim were found to contribute significantly to glucocorticoid-induced killing. Our results thus establish that Puma and Bim are key initiators of gamma-radiation- and glucocorticoid-induced apoptosis in lymphoid cells in vivo.
authors.affiliation: Division of Experimental Pathophysiology & Immunology, Biocenter, Innsbruck Medical University, A-6020 Innsbruck, Austria.
authors.forename: Miriam
authors.initials: M
authors.lastname: Erlacher
authors.forename: Ewa M
authors.initials: EM
authors.lastname: Michalak
authors.forename: Priscilla N
authors.initials: PN
authors.lastname: Kelly
authors.forename: Verena
authors.initials: V
authors.lastname: Labi
authors.forename: Harald
authors.initials: H
authors.lastname: Niederegger
authors.forename: Leigh
authors.initials: L
authors.lastname: Coultas
authors.forename: Jerry M
authors.initials: JM
authors.lastname: Adams
authors.forename: Andreas
authors.initials: A
authors.lastname: Strasser
authors.forename: Andreas
authors.initials: A
authors.lastname: Villunger
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects*; D051017:Apoptosis Regulatory Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D000072224:Bcl-2-Like Protein 11; D002454:Cell Differentiation; D003907:Dexamethasone / Q000494:pharmacology; D005720:Gamma Rays; D005938:Glucocorticoids / Q000494:pharmacology*; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000528:radiation effects*; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D025521:Tumor Suppressor Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; C000606776:Bcl2l11 protein, mouse; D005938:Glucocorticoids; D008565:Membrane Proteins; C488588:PUMA protein, mouse; D011518:Proto-Oncogene Proteins; D025521:Tumor Suppressor Proteins; D003907:Dexamethasone