Olfactory cleft proteome does not reflect olfactory performance in patients with idiopathic and postinfectious olfactory disorder: A pilot study.

Technical advances including liquid chromatography-tandem mass spectrometry and its data analysis enable detailed proteomic analysis of the nasal mucus. Alterations of the nasal mucus proteome may provoke substantial changes of the nasal physiology and have already been associated with rhinologic diseases such as allergic rhinitis. This study was conducted as a pilot study to map the olfactory cleft proteome using current techniques for proteomic analysis. Furthermore, we aimed to investigate proteomic changes as potential biomarkers in patients suffering from idiopathic and postinfectious olfactory disorders compared to healthy controls. Seven patients with idiopathic hyposmia and anosmia, seven patients with postinfectious hyposmia and anosmia and seven healthy controls were included in this study. In total, 1117 different proteins were detected in at least five patients in at least one group. Results of this study did not reveal significant differences regarding the proteomic composition of the olfactory cleft mucus between patients versus healthy controls. Among proteins involved in olfactory perception the G protein family was detected but also found unchanged between groups. Investigation of protein composition by liquid chromatography-tandem mass spectrometry enabled us to perform an in-depth analysis of the olfactory cleft mucus proteome regarding the diversity of different proteins in individual patients. However untargeted proteomics of the olfactory cleft mucus may not be an applicable approach to develop biomarkers for olfactory disorders. Targeted analyses of distinct proteins known to be involved in olfactory perception but not detected by our approach, e.g. odorant binding proteins, may provide more information regarding pathophysiology of olfactory diseases.

Seasonal proteome changes of nasal mucus reflect perennial inflammatory response and reduced defence mechanisms and plasticity in allergic rhinitis.

INTRODUCTION: Nasal mucus and its proteins are a defence against allergens. We sought to investigate dynamic proteome changes in allergic rhinitis upon environmental allergen provocation. METHODS: Nasal mucus was collected in and out of pollen season from allergic rhinitis patients (N=10) and healthy controls (N=12). Liquid chromatography-tandem mass spectrometry was performed. Proteins were identified by SwissProt database search and quantified from normalized areas under curve of precursor ion chromatograms. Gene enrichment analysis was performed with Cytoscape/BINGO software. RESULTS: In total 430 different proteins were detected in both groups, 203 (47.2%) were newly identified. In allergics CLU and IGKC were significantly more abundant in season (2.2 and 2.1-fold respectively). GSTP1 (0.5-fold), ELANE (0.4-fold), HIST1H2BK (0.3-fold), S100A8 (0.2-fold), S100A12 (0.2-fold) and ARHGDIB (0.1-fold) were significantly less abundant in season. In healthy controls UBC, TUBA1B, HBB and FABP5 were only present in season. Ig kappa chain V-I region DEE (5.3-fold), CLU (5.0-fold), TXN (4.3-fold), MSMB (3.2-fold) and Ig heavy chain V-III region BRO (2.7-fold) were significantly more abundant in season. MUC5B (0.5-fold), SLPI (0.2-fold) and S100P (0.2-fold) were significantly less abundant in season. CONCLUSION: Contrary to their symptoms allergic rhinitis patients show perennial inflammatory response lacking adequate reaction to allergens in season. BIOLOGICAL SIGNIFICANCE: Many studies dealing with allergic rhinitis are focused on the nasal epithelium. This is the first study to analyse the nasal mucus as primary defence barrier on a proteomic level in and out of pollen season and contrary to the leading opinion shows that allergic patients show a perennial inflammatory response with reduced reaction to allergens whereas healthy controls react on proteome basis towards enhanced defence in season despite lacking allergic sensitization.

Apolipoproteins have a potential role in nasal mucus of allergic rhinitis patients: a proteomic study.

OBJECTIVES/HYPOTHESIS: Nasal mucus is a defense barrier against aeroallergens. We recently found apolipoproteins to be elevated in the nasal mucus of allergic rhinitis patients. Apolipoproteins are involved in lipid metabolism, have immunomodulatory properties, and may represent interesting novel biomarkers. This study aims to validate our findings and analyze whether the increased abundance of apolipoproteins in nasal mucus is a local or systemic phenomenon in allergic rhinitis. STUDY DESIGN: Prospective controlled trial. METHODS: Nasal mucus of allergic rhinitis patients (n = 10) and healthy controls (n = 12) was collected, tryptically digested, and analyzed by LC-MS/MS. Areas under the curve (AUCs) of the total peptides identified and matched to apolipoproteins were used to compare relative protein abundances of the same protein between groups. RESULTS: In a total of 389 identified proteins in nasal mucus, apolipoproteins A-I, A-II, A-IV, and B 100 were detected. Apolipoprotein A-I (mean normalized AUC 1.49% [SEM = 0.5] vs. 0.42% [SEM = 0.2]) and A-II (mean normalized AUC 0.47% [SEM = 0.2] vs. 0.05% [SEM = 0.02]) were significantly more abundant in allergic rhinitis patients than controls (3.6-fold and 9.4-fold, respectively). Apolipoprotein A-IV (mean normalized AUC = 0.01%) and B-100 (mean normalized AUC = 0.02%) were each detected in only one allergic rhinitis patient out of 10. Myeloperoxidase was detected with a mean normalized AUC of 0.06% (SEM = 0.03) in allergic rhinitis patients and 0.18% (SEM = 0.08) in healthy controls without reaching significance. CONCLUSION: This study confirms the significantly higher abundance of apolipoproteins A-I and AII in allergic rhinitis mucus. Their release seems to be triggered by local mechanisms as an antiinflammatory response to allergens.

Gel-based mass spectrometric analysis of hippocampal transmembrane proteins using high resolution LTQ Orbitrap Velos Pro.

Membrane proteins (MPs) play diverse important roles for physical interactions, cell communication, molecular transport, and signal transduction. Membrane proteins comprise approximately 25∼35% of the genome in living organisms, but there are difficulties in the analysis at the protein chemical level, in particular due to low abundance and limited solubility. Sequence information on membrane proteins and their complexes would be beneficial to elucidate their function. Proteins were extracted from pooled whole mouse brains, enriched membrane fractions were prepared using either two commercially available kits or 6-aminocaproic acid under denaturing or native conditions followed by gel-based proteomic approaches using blue native (BN-) and SDS-PAGE with subsequent in-gel digestion with several proteases, chymotrypsin, trypsin followed by nano-LC-ESI-MS/MS analysis on LTQ Orbitrap Velos Pro. By combining three different extraction methods and two separation methods, 28.39% of proteins were identified as either "integral" or "anchored/integral" MPs based on UniProtKB database searches. MPs with more than six transmembrane domains (TMDs) were identified more efficiently from BN-PAGE separation although a higher number of proteins was identified from SDS-PAGE separation. Comparative analysis of MPs containing TMDs via gel-based LC-MS/MS using BN-PAGE and SDS-PAGE may be useful to increase the number of identified membrane proteins in brain. All MS data have been deposited in the ProteomeXchange with identifier PXD000311 (http://proteomecentral.proteomexchange.org/dataset/PXD000311).

Nasal mucus proteomic changes reflect altered immune responses and epithelial permeability in patients with allergic rhinitis.

BACKGROUND: Nasal mucus is the first-line defense barrier against (aero-) allergens. However, its proteome and function have not been clearly investigated. OBJECTIVE: The role of nasal mucus in the pathophysiology of allergic rhinitis was investigated by analyzing its proteome in patients with allergic rhinitis (n = 29) and healthy control subjects (n = 29). METHODS: Nasal mucus was collected with a suction device, tryptically digested, and analyzed by using liquid chromatography-tandem mass spectrometry. Proteins were identified by searching the SwissProt database and annotated by collecting gene ontology data from databases and existing literature. Gene enrichment analysis was performed by using Cytoscape/BINGO software tools. Proteins were quantified with spectral counting, and selected proteins were confirmed by means of Western blotting. RESULTS: In total, 267 proteins were identified, with 20 (7.5%) found exclusively in patients with allergic rhinitis and 25 (9.5%) found exclusively in healthy control subjects. Five proteins were found to be significantly upregulated in patients with allergic rhinitis (apolipoprotein A-2 [APOA2], 9.7-fold; α2-macroglobulin [A2M], 4.5-fold; apolipoprotein A-1 [APOA1], 3.2-fold; α1-antitrypsin [SERPINA1], 2.5-fold; and complement C3 [C3], 2.3-fold) and 5 were found to be downregulated (antileukoproteinase [SLPI], 0.6-fold; WAP 4-disulfide core domain protein [WFDC2], 0.5-fold; haptoglobin [HP], 0.7-fold; IgJ chain [IGJ], 0.7-fold; and Ig hc V-III region BRO, 0.8-fold) compared with levels seen in healthy control subjects. CONCLUSION: The allergic rhinitis mucus proteome shows an enhanced immune response in which apolipoproteins might play an important role. Furthermore, an imbalance between cysteine proteases and antiproteases could be seen, which negatively affects epithelial integrity on exposure to pollen protease activity. This reflects the important role of mucus as the first-line defense barrier against allergens.