Journal Article

Proteomic Analysis of Pure Human Airway Gland Mucus Reveals a Large Component of Protective Proteins

John F. Engelhardt, Jeffrey J. Wine, Nam Soo Joo, Idil A. Evans, Hyung Ju Cho, Il Ho Park

2015

Overview

Airway submucosal glands contribute to innate immunity and protect the lungs by secreting mucus, which is required for mucociliary clearance and which also contains antimicrobial, anti-inflammatory, anti-proteolytic and anti-oxidant proteins. We stimulated glands in tracheal trimmings from three lung donors and collected droplets of uncontaminated mucus as they formed at the gland orifices under an oil layer. We analyzed the mucus using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Analysis identified 5486 peptides and 441 proteins from across the 3 samples (269-319 proteins per subject). We focused on 269 proteins common to at least 2 0f 3 subjects, of which 102 (38%) had protective or innate immunity functions. While many of these have long been known to play such roles, for many others their cellular protective functions have only recently been appreciated in addition to their well-studied biologic functions (e.g. annexins, apolipoproteins, gelsolin, hemoglobin, histones, keratins, and lumican). A minority of the identified proteins are known to be secreted via conventional exocytosis, suggesting that glandular secretion occurs via multiple mechanisms. Two of the observed protective proteins, major vault protein and prohibitin, have not been observed in fluid from human epithelial cultures or in fluid from nasal or bronchoalveolar lavage. Further proteomic analysis of pure gland mucus may help clarify how healthy airways maintain a sterile environment.

• Publisher: Public Library of Science (PLoS),Public Library of Science
• Subject: Alveoli / Analysis / Annexins / Apolipoproteins / Bronchoalveolar lavage / Bronchus / Bubbles / Chromatography / Cystic fibrosis / Exocytosis / Fluid / Fluids / Gastroenterology / Gelsolin / Glands / Hemoglobin / Hemoglobins / Histones / Humans / Immunity / Inflammation / Innate immunity / Keratin / Keratins / Kinases / Laboratories / Liquid chromatography / Lungs / Mass spectrometry / Mass spectroscopy / Medicine / Mineral oils / Mucociliary Clearance / Mucus / Mucus - metabolism / Organ donors / Orifices / Otolaryngology / Oxidizing agents / Peptides / Prohibitin / Proteins / Proteolysis / Proteomics / Q / R / Research Article / Respiratory Mucosa / Respiratory Mucosa - metabolism / Respiratory System / Respiratory System - metabolism / Respiratory tract / Science