Down-regulation of the Anti-inflammatory Protein Annexin A1 in Cystic Fibrosis Knock-out Mice and Patients

• Published in: Molecular & cellular proteomics Vol. 4; no. 10; pp. 1591 - 1601
• Main Authors: Bensalem, Noura, Ventura, Ana Paula, Vallée, Benoît, Lipecka, Joanna, Tondelier, Danielle, Davezac, Noélie, Dos Santos, Alexandre, Perretti, Mauro, Fajac, Anne, Sermet-Gaudelus, Isabelle, Renouil, Michel, Lesure, Jean-François, Halgand, Frédéric, Laprévote, Olivier, Edelman, Aleksander
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 01.10.2005
• Subjects: Adolescent; Adult; Amino Acid Sequence; Animals; Annexin A1 - chemistry; Annexin A1 - metabolism; Case-Control Studies; Child; Child, Preschool; Codon, Nonsense - genetics; Colon - cytology; Colon - metabolism; Colon - pathology; Cystic Fibrosis - genetics; Cystic Fibrosis - metabolism; Cystic Fibrosis Transmembrane Conductance Regulator - deficiency; Cystic Fibrosis Transmembrane Conductance Regulator - genetics; Down-Regulation - genetics; Electrophoresis, Gel, Two-Dimensional; Homozygote; Humans; Lung - cytology; Lung - metabolism; Lung - pathology; Mice; Mice, Knockout; Molecular Sequence Data; Muscle, Skeletal - cytology; Muscle, Skeletal - metabolism; Muscle, Skeletal - pathology; Nasal Mucosa - cytology; Nasal Mucosa - metabolism; Nasal Mucosa - pathology; Pancreas - cytology; Pancreas - metabolism; Pancreas - pathology; Protein Transport; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
• ISSN: 1535-9476; 1535-9484
• DOI: 10.1074/mcp.M500019-MCP200

Cystic fibrosis is a fatal human genetic disease caused by mutations in the CFTR gene encoding a cAMP-activated chloride channel. It is characterized by abnormal fluid transport across secretory epithelia and chronic inflammation in lung, pancreas, and intestine. Because cystic fibrosis (CF) pathophysiology cannot be explained solely by dysfunction of cystic fibrosis transmembrane conductance regulator (CFTR), we applied a proteomic approach (bidimensional electrophoresis and mass spectrometry) to search for differentially expressed proteins between mice lacking cftr ( cftr tm1Unc , cftr −/− ) and controls using colonic crypts from young animals, i.e. prior to the development of intestinal inflammation. By analyzing total proteins separated in the range of pH 6–11, we detected 24 differentially expressed proteins (>2-fold). In this work, we focused on one of these proteins that was absent in two-dimensional gels from cftr −/− mice. This protein spot (molecular mass, 37 kDa; pI 7) was identified by mass spectrometry as annexin A1, an anti-inflammatory protein. Interestingly, annexin A1 was also undetectable in lungs and pancreas of cftr −/− mice, tissues known to express CFTR. Absence of this inhibitory mediator of the host inflammatory response was associated with colonic up-regulation of the proinflammatory cytosolic phospholipase A 2 . More importantly, annexin A1 was down-regulated in nasal epithelial cells from CF patients bearing homozygous nonsense mutations in the CFTR gene (Y122X, 489delC) and differentially expressed in F508del patients. These results suggest that annexin A1 may be a key protein involved in CF pathogenesis especially in relation to the not well defined field of inflammation in CF. We suggest that decreased expression of annexin A1 contributes to the worsening of the CF phenotype.