In vivo alterations of IFN regulatory factor-1 and PIAS1 protein levels in cystic fibrosis epithelium.
Inducible nitric oxide synthase-2 (NOS2) expression has been shown to be reduced in cystic fibrosis (CF) epithelial cells. Reduced NOS2 expression is unexpected, given the inflammatory nature of CF airway disease, and is an indication that cell-signaling mechanisms necessary for proper NOS2 regulation are probably altered in CF epithelium. Therefore, we examined the expression levels of regulatory factors necessary for NOS2 expression in CF epithelium and showed that IFN regulatory factor-1 (IRF-1) is necessary for full NOS2 expression. Mice lacking IRF-1 expression have diminished epithelial NOS2 expression, as well as reduced NO-dependent chloride transport across the nasal epithelia. Furthermore, IRF-1 protein expression is reduced in nasal and intestinal epithelial cells from CF mice, suggesting a possible mechanism for the CF-related reduction of epithelial NOS2 expression. Active signal transducer and activator of transcription-1 (Stat1) is necessary for both NOS2 and IRF-1 expression. We found that protein levels of Stat1 were increased in CF cells, but that the active phosphorylated form of Stat1 was bound to the protein inhibitor of activated Stat1 (PIAS1). We propose that increased levels of PIAS1 diminish certain cell-signaling pathways, resulting in reduced IRF-1 and NOS2 expression in CF epithelial cells.
Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio 44106-4948, USA. tjk12@po.cwru.edu
T J
TJ
Kelley
H L
HL
Elmer
D000818:Animals; D003550:Cystic Fibrosis / Q000235:genetics / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D050856:Interferon Regulatory Factor-1; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008817:Mice, Mutant Strains; D009297:Nasal Mucosa / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D050828:Protein Inhibitors of Activated STAT; D011506:Proteins / Q000378:metabolism*; D050794:STAT1 Transcription Factor; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism
C505032:CFTR protein, human; D004268:DNA-Binding Proteins; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; C494258:Irf1 protein, mouse; D010750:Phosphoproteins; C494211:Pias1 protein, mouse; D050828:Protein Inhibitors of Activated STAT; D011506:Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; C494080:Stat1 protein, mouse; D015534:Trans-Activators; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse