Increased sensitivity of Fancc-deficient hematopoietic cells to nitric oxide and evidence that this species mediates growth inhibition by cytokines.
Fanconi anemia complementation group C (Fancc)-deficient murine bone marrow progenitors demonstrate increased sensitivity to growth inhibition by interferon gamma (IFNgamma), tumor necrosis factor alpha (TNFalpha), and macrophage inflammatory protein 1alpha (MIP-1alpha). This property has been proposed as a possible pathogenic factor in the marrow failure seen in Fanconi anemia. Supporting our hypothesis that nitric oxide (NO) production might be a common effector in this sensitivity, we found that cytokine-mediated growth inhibition of Fancc(-/-) bone marrow cells was prevented by inhibiting NO synthase activity. Interestingly, Fancc(-/-) hematopoietic cells also exhibited increased growth inhibition on exposure to 2 distinct NO-generating agents, S-nitroso-N-acetyl-D, L-penicillamine (SNAP) and diethylenetriamine nitric oxide adduct (DETA/NO). In keeping with the sensitivity of Fancc(-/-) cells to IFNgamma, inducible nitric oxide synthase (iNOS) levels and nitrite release were both increased following stimulation of Fancc(-/-) macrophages with this cytokine, either alone or in combination with bacterial lipopolysaccharide. Suggesting a plausible mechanism for the increased expression of iNOS, IFNgamma-stimulated Fancc(-/-) macrophages generated higher levels of phospho-Stat1, a positive regulator of inos (nos2) gene expression. These observations, while confined to C57BL/6 Fancc(-/-) hematopoietic cells, raise the possibility that nitric oxide has a role in the pathogenesis of Fanconi anemia.
Hadjur
Suzana
S
Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada.
Jirik
Frank R
FR
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D018797:Cell Cycle Proteins; D002455:Cell Division / Q000187:drug effects; D003114:Colony-Forming Units Assay; D016207:Cytokines / Q000494:pharmacology*; D004268:DNA-Binding Proteins; D052218:Fanconi Anemia Complementation Group C Protein; D051856:Fanconi Anemia Complementation Group Proteins; D005434:Flow Cytometry; D017353:Gene Deletion; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009569:Nitric Oxide / Q000494:pharmacology*; D009687:Nuclear Proteins; D011506:Proteins / Q000235:genetics*
D018797:Cell Cycle Proteins; D016207:Cytokines; D004268:DNA-Binding Proteins; C497652:Fancc protein, mouse; D052218:Fanconi Anemia Complementation Group C Protein; D051856:Fanconi Anemia Complementation Group Proteins; D009687:Nuclear Proteins; D011506:Proteins; D009569:Nitric Oxide