title: Selective roles for antiapoptotic MCL-1 during granulocyte development and macrophage effector function.
abstract: During hematopoiesis, myeloid cell leukemia-1 (MCL-1) mediates the survival of bone marrow progenitors and lymphocytes. However, its requirement during myeloid cell differentiation, development, and effector function is less clear. Lineage-specific deletion of MCL-1 in myeloid precursors results in neutropenia due to death during differentiation. The loss of mature neutrophils induced by Mcl-1 deletion was not rescued by genetic deletion of proapoptotic Bim and Puma or by exogenous cytokine treatment. However, blockade of intrinsic apoptosis by lineage-specific deletion of both multidomain proapoptotics Bax and Bak was capable of rescuing the neutropenia associated with Mcl-1 deletion. In the monocytic lineage, despite efficient Mcl-1 deletion, monocytes and macrophages undergo normal development. During the phagocytosis of extracellular bacteria, macrophages concomitantly increase the expression of both MCL-1 and BIM. However, Mcl-1-deficient macrophages exhibit increased sensitivity to death during bacterial phagocytosis that can be abolished by codeletion of Bim. These data suggest that MCL-1 may be necessary to antagonize BIM during macrophage effector responses. Thus, MCL-1 plays selective roles in myeloid development, being required for neutrophil development and setting the threshold for apoptosis during a macrophage effector response.
authors.affiliation: Department of Biochemistry, St Jude Children's Research Hospital, Memphis, TN 38105, USA.
authors.forename: Desiree A
authors.initials: DA
authors.lastname: Steimer
authors.forename: Kelli
authors.initials: K
authors.lastname: Boyd
authors.forename: Osamu
authors.initials: O
authors.lastname: Takeuchi
authors.forename: Jill K
authors.initials: JK
authors.lastname: Fisher
authors.forename: Gerard P
authors.initials: GP
authors.lastname: Zambetti
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Opferman
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D051017:Apoptosis Regulatory Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D000072224:Bcl-2-Like Protein 11; D001854:Bone Marrow Cells / Q000166:cytology; D004926:Escherichia coli; D000069585:Filgrastim; D017353:Gene Deletion; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D006098:Granulocytes / Q000166:cytology*; D008262:Macrophage Activation / Q000502:physiology*; D017737:Macrophages, Peritoneal / Q000166:cytology* / Q000502:physiology; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D038042:Myelopoiesis / Q000187:drug effects / Q000502:physiology*; D009928:Organ Specificity; D010587:Phagocytosis; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000502:physiology*; D011994:Recombinant Proteins; D013047:Specific Pathogen-Free Organisms; D025521:Tumor Suppressor Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D051028:bcl-2-Associated X Protein / Q000172:deficiency / Q000235:genetics / Q000502:physiology
chemical_list: D051017:Apoptosis Regulatory Proteins; C494773:Bak1 protein, mouse; C494827:Bax protein, mouse; D000072224:Bcl-2-Like Protein 11; C000606776:Bcl2l11 protein, mouse; C579094:Mcl1 protein, mouse; D008565:Membrane Proteins; D064549:Myeloid Cell Leukemia Sequence 1 Protein; C488588:PUMA protein, mouse; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011994:Recombinant Proteins; D025521:Tumor Suppressor Proteins; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D016179:Granulocyte Colony-Stimulating Factor; D000069585:Filgrastim