Seasonal differences in nasal mucus proteome and impact of immunotherapy

Nasal mucus as first line defense barrier of the nasal mucosa contains a variety of proteins that act as functional units. We recently showed that the nasal mucus proteome between allergic rhinitis patients and healthy controls is significantly altered. On protein level, immune response in allergic rhinitis is enhanced and barrier function is reduced as reflected by increased epithelial permeability. Moreover, there is an unfavorable imbalance in innate anti-proteases. Proteases in pollen grain could therefore not be adequately deactivated in the mucus further damaging the epithelium which leads to submucosal penetration of allergens and facilitated presentation to antigen presenting cells. The aim of the present project is to show changes in nasal mucus proteome between allergic rhinitis patients and healthy controls over the pollen and non pollen season and to further determine whether and if so how the proteome changes under immunotherapy. For the first aim patients and healthy controls will be enrolled at two time points namely during the pollen season and out of the pollen season. Statistical differences will be determined within the groups and between the groups. The protein changes over the time course reflect how allergics but also healthy controls react to allergen challenge. The results should give insight on possible biomarkers that could be used for diagnostics and therapy. Protein substitution or inhibition may be a future therapy to reinforce the barrier function of nasal mucus and treat allergic rhinitis symptoms. The effect of immunotherapy as sole causal therapy will be determined and therapy responders will be compared to non-responders. We hypothesize that responders will show proteome changes similar to healthy conditions. This further concretizes distinct proteins as biomarkers that could be used as therapeutic agents. Moreover proteome changes could be used to predict and monitor therapeutic success or failure and patients may be stratified to be subjected to other therapeutic strategies than immunotherapy saving time and money. Mucus will be collected with a special suction device equipped with a mucus trap. Then, proteomic analysis will be performed by LC MS/MS mass spectrometry. Database search will identify distinct proteins and their function, origin etc. will be annotated. Protein groups will be analyzed through pathway enrichment and cluster analysis. By this means complex proteomic data can be visualized for a better understanding of global changes in protein networks and functions. Investigating the nasal mucus proteome in diseased and healthy state leads to a better understanding of its barrier function and reaction to allergens. Distinct proteins and/or proteins groups could be used as biomarkers for novel diagnostic and therapeutic approaches. Furthermore, mechanisms of immunotherapy in responders and success or failure of therapy could be determined.

Allergic rhinitis, better known as hay fever, affects up to 40% of the population in certain countries regardless of sex, age or social status. The causes of this disease are allergens in the form of pollen, animal fur, mite feces, etc. which for healthy people are harmless but cause inflammatory reactions in allergic patients. In allergic rhinitis, it is usually pollen from trees and grasses that are responsible for inflammatory reactions when in contact with the body during pollen season. This leads to the production of antibodies (so-called IgE) which when cross-linked to inflammatory cells results in release of substances which provoke symptoms such as sneezing, runny nose, tearing and itching. These processes basically happen in the nasal mucous membrane (mucosa) and the conjunctiva of the eye whose first defense barrier is the nasal secretion or tear fluid respectively. The aim of this project was to investigate the defense function of the nasal secretion and the tear film at the protein level and to determine how the proteome is regulated inside and outside the pollen season. The results should show which proteins or protein groups are responsible for the inflammatory response compared to healthy controls and improve understanding of the underlying processes during the course of allergic reactions. In total, more than 400 proteins were identified via a mass-spectrometric approach in nasal secretions, which represents the largest number of proteins found to date. In the tear fluid, 90 proteins were identified. Ten of these nasal secretion proteins showed significant differences in their abundance among allergic patients within the pollen season compared to healthy controls. The function of these proteins is mainly related to defense processes that were reduced in allergic patients and inflammatory processes that in contrast were increased compared to healthy controls. The most interesting result was the analysis of biological processes of the whole set of the proteins (the so-called proteome) which showed that allergic patients, unlike their course of symptoms, showed little response to the stress of pollen during the season. In contrast, healthy controls showed a marked response of their proteome in season to counteract the natural provocation of pollen. Similarly, the proteome of tears reacted in a seasonal comparison between allergy sufferers and healthy people. This finding could lead to a paradigm shift in allergy research as the analysis of healthy controls and their involvement with pollen have not been in the main focus so far. Key proteins and protein groups, and their more detailed functional analysis in pollen defense and preservation of the natural barrier of nasal secretions and tears, could serve as biomarkers in the future, allowing for better diagnostics and response to therapies, as well as targeting new therapeutic approaches.