title: Interferon-gamma attenuates the survival activity of G-CSF through PI3K/Akt signaling pathway in mouse multipotent progenitor cells.
abstract: Apoptosis plays an important role in the injury to stem and progenitor compartments associated with aberrant interferon-gamma (IFN-gamma) in aplastic anemia (AA), which is characterized by the loss of stem cells; however, its molecular mechanism is poorly understood. In this study, we have addressed the mechanism of the apoptotic function of IFN-gamma against hematopoietic stem and/or progenitors. Although granulocyte colony-stimulating factor (G-CSF) augmented survival and proliferative and differentiating activity in 32D cells, mouse multipotent progenitor cells, these effects were abolished by IFN-gamma and were susceptible to apoptosis with IFN-gamma. IFN-gamma attenuated Akt phosphorylated by G-CSF in a dose- and time-dependent manner. Wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K), enhanced the inhibitory effect on Akt phosphorylated by G-CSF in collaboration with IFN-gamma, suggesting that the activity of IFN-gamma might converge on the PI3K pathway. We examined the expression of Bcl-2-associated death (Bad), which works downstream of Akt. IFN-gamma increased the Bad protein reduced by G-CSF. IFN-gamma induced apoptosis in 32D cells through the caspase pathway. Taken together, these results suggest that IFN-gamma could exert inhibitory action on stem cells and/or progenitors by interference with the PI3K/Akt signaling pathway. Our findings may contribute to understanding the decreased number of stem cells characteristic of AA.
authors.affiliation: Department of Hematology and Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Keichiro
authors.initials: K
authors.lastname: Mihara
authors.forename: Guoqi
authors.initials: G
authors.lastname: Song
authors.forename: Hideo
authors.initials: H
authors.lastname: Tanaka
authors.forename: Akiro
authors.initials: A
authors.lastname: Kimura
mesh_terms: D000741:Anemia, Aplastic / Q000378:metabolism / Q000473:pathology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D016179:Granulocyte Colony-Stimulating Factor / Q000378:metabolism / Q000494:pharmacology*; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism / Q000494:pharmacology*; D051379:Mice; D039902:Multipotent Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011994:Recombinant Proteins; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor; D007371:Interferon-gamma; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt