title: An oxidative mechanism of interferon induced priming of the Fas pathway in Fanconi anemia cells.
abstract: Hematopoietic progenitor cells from children with Fanconi anemia of the C complementation group (FA-C) are excessively apoptotic and hypersensitive to various extracellular cues including Fas-ligand, tumor necrosis factor-alpha and double-stranded RNA. Interferon (IFN)-gamma is known to augment apoptotic responses of these factors. The "priming" effect of IFN-gamma is not fully explained. In view of the strong evidence that FA cells are intolerant of oxidative stress, we tested the notion that IFN-priming involves the induction of reactive oxygen species (ROS) in two FA-C B-lymphocyte cell lines and in peripheral blood neutrophils and mononuclear cells of FA patients. We also investigated whether the combination of IFN-gamma and Fas created an intracellular environment that promoted apoptosis. Significantly lower doses of IFN-gamma induced ROS accumulation in neutrophils and mononuclear cell of FA patients compared to cells of normal individuals. Enhanced ROS accumulation and decreased intracellular glutathione levels were observed in FA-C B-cell lines primed with IFN-gamma and treated with agonistic anti-Fas antibody than in isogenic control cells corrected with FANCC. The above treatment also induced caspase-3 and -8 activation as well as apoptosis. That antioxidants reduced the priming effect of IFN-gamma in Fas and IFN-gamma-treated FA lymphoblast cells, demonstrates that ROS represent a critical effector mechanism for the exaggerated responses to IFN-gamma characteristic of FA-C cells.
authors.affiliation: Department of Cell Biology and Histology, Sackler Faculty of Medicine, Tel-Aviv University, Israel.
authors.forename: Michal
authors.initials: M
authors.lastname: Pearl-Yafe
authors.forename: Drora
authors.initials: D
authors.lastname: Halperin
authors.forename: Ayelet
authors.initials: A
authors.lastname: Halevy
authors.forename: Henry
authors.initials: H
authors.lastname: Kalir
authors.forename: Bella
authors.initials: B
authors.lastname: Bielorai
authors.forename: Ina
authors.initials: I
authors.lastname: Fabian
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D058846:Antibodies, Monoclonal, Murine-Derived; D017209:Apoptosis; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002461:Cell Line, Transformed; D003683:Dehydroascorbic Acid / Q000494:pharmacology; D005199:Fanconi Anemia / Q000473:pathology*; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism; D019014:fas Receptor / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D017382:Reactive Oxygen Species; C411023:anti-Fas monoclonal antibody; D019014:fas Receptor; D007371:Interferon-gamma; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; D005978:Glutathione; D003683:Dehydroascorbic Acid