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A2849 - Airways Mucus Proteome Reveals Unique and Common Pathways in Non-CF Bronchiectasis and Primary Ciliary Dyskinesia
Author Block: G. Radicioni1, K. A. Ramsey1, M. McGuckin2, M. R. Knowles1, R. C. Boucher1, M. Kesimer1; 1Marsico Lung Institute, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 2Inflammatory Disease Biology and Therapeutics Group, Mater Research Institute University of Queensland, Brisbane, Australia.
Rationale The human airway is lined by mucus, a secreted hydrogel consisting of proteins, salt, and water. Airway mucins, particularly MUC5AC and MUC5B, are the major polymers in normal mucus that generate the gel-like properties required for mucociliary clearance, but over a hundred other proteins also contribute to mucus properties. Non-CF Bronchiectasis (NCFB) and primary ciliary dyskinesia (PCD) are two chronic muco-obstructive disorders characterized by airflow obstruction and infections. PCD is an autosomal recessive hereditary disease characterized by motile ciliary dysfunction. NCFB has multiple etiologies, and is characterized by irreversible airway dilation. The aim of this study was to investigate the role of mucins and other secreted proteins in sputum from subjects with PCD or NCFB compared to healthy controls. Methods To study the sputum proteome, samples (healthy n=12, NCFB n=10, and PCD n=9) were digested with trypsin and analyzed by tandem mass spectrometry (Q-Exactive Orbitrap UPLC MS/MS System). Proteins were label free quantified using the total ion precursor intensity of peptides detected with high confidence, and data were compared with Kruskal-Wallis Test followed by Dunn's multiple comparisons test. MUC5B and MUC5AC were quantified by stable isotope labeled mass spectrometry in 88 samples (healthy n=19, IB n=30, and PCD n=39). Results Approximately 200 proteins exhibited significant differences between the three sample types: 69 proteins were significantly different in the NCFB group, 23 in the PCD group, and 104 were significantly different in both groups compared to control. Pathway analysis of both proteomes showed activation of lung injury and tumor pathways. Based on stable isotope labeled mass spectrometry, both MUC5AC and MUC5B significantly increased in both diseases relative to controls. Neutrophil collagenase and eosinophil peroxidase were higher, and BPI fold-containing family B members 1 and 2 and family A member 2 were decreased, in both groups. Mucin-4, mucin-16, trefoil factor 3, IgGFC-binding protein, and pulmonary-surfactant-associated protein B were increased in NCFB, whereas mucin-7 and neutrophil gelatinase-associated glycoprotein were significantly increased in PCD. Polymeric immunoglobulin receptor and uteroglobin were selectively decreased in PCD. Conclusion Our results show that both NCFB and PCD share features of mucin (MUC5B and MUC5AC) hyperconcentration. Neutrophil and eosinophil enzymes were elevated in NCFB and PCD, whereas disease-specific proteome patterns were also observed in PCD and NCFB.