Quantitative proteomics of nasal mucus in chronic sinusitis with nasal polyposis

Background: Proteomics has been used as a tool for identification of the protein content of nasal mucus in diseased and healthy subjects. Thirty-five proteins in both chronic rhinosinusitis (CRS) and control groups were identified in a previous study by our group using conventional mass spectrometry analysis. Ten of these proteins were related to innate and acquired immunity and showed differences in expression between the two groups. Objective: To investigate the quantitative differential expression of specific nasal mucus proteins previously identified by our group using multiple reaction monitoring (MRM) mass spectrometry in patients with CRS with nasal polyposis compared with normal subjects. Methods: In a prospective case control study, nasal mucus from patients and control subjects was collected, desalted, resolubilized, and digested using proteolytic enzymes. Previously identified nasal mucus proteins with differential expression in CRS patients were targeted and quantitatively measured using MRM mass spectrometry. Results: Analysis of 12 samples (6 patients and 6 controls) identified 7 of the 10 targeted proteins, many of which were related to innate and acquired immunity. Quantitative analysis showed differential expression in CRS patients compared with control subjects. A detailed analysis and characterization of the protein isolates is outlined. Conclusion: This is the first proteomics study of nasal mucus in CRS with polyposis using the MRM technique. The findings suggest that innate and acquired immunity may play a role in the pathophysiology of CRS. Future steps in evaluating the protein characteristics of the mucus of CRS patients are aimed at developing biomarkers and potentially targeted therapies.