Identification of Proteases and Protease Inhibitors in Allergenic and Non-Allergenic Pollen.

Barbara Höllbacher,Fatima Ferreira,Heidi Hofer,Peter Lackner,Armin Schmitt

doi:10.3390/ijms18061199

Barbara Höllbacher, Fatima Ferreira + Show 3 more

Open Access

https://doi.org/10.3390/ijms18061199

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Abstract

Pollen is one of the most common causes of allergy worldwide, making the study of their molecular composition crucial for the advancement of allergy research. Despite substantial efforts in this field, it is not yet clear why some plant pollens strongly provoke allergies while others do not. However, proteases and protease inhibitors from allergen sources are known to play an important role in the development of pollen allergies. In this study, we aim to uncover differences in the transcriptional pattern of proteases and protease inhibitors in Betula verrucosa and Pinus sylvestris pollen as models for high and low allergenic potential, respectively. We applied RNA sequencing to Betula verrucosa and Pinus sylvestris pollen. After de-novo assembly we derived general functional profiles of the protein coding transcripts. By utilization of domain based functional annotation we identified potential proteases and protease inhibitors and compared their expression in the two types of pollen. Functional profiles are highly similar between Betula verrucosa and Pinus sylvestris pollen. Both pollen contain proteases and inhibitors from 53 and 7 Pfam families, respectively. Some of the members comprised within those families are implicated in facilitating allergen entry, while others are known allergens themselves. Our work revealed several candidate proteins which, with further investigation, represent exciting new leads in elucidating the process behind allergic sensitization.

Highlights

In Europe, more than 20% of the population is affected by allergic rhinitis, where more than 50% of the cases are triggered by pollen [1]
Betula verrucosa and Pinus sylvestris are common in the northern parts of Europe and Asia, where Pinus sylvestris extents to some southern areas [6]
Pollen of Betula verrucosa has a spherical/triangular shape with a diameter of about 25 μm, while Pinus sylvestris has saccate pollen grains possessing a pair of air sacs, which leads to a maximum diameter of about 70 μm [8]

Summary

Introduction

In Europe, more than 20% of the population is affected by allergic rhinitis, where more than 50% of the cases are triggered by pollen [1]. Many of the major allergens in pollen have been identified [3,4,5] It is still unclear, why some pollen, e.g., from Betula verrucosa, strongly provoke allergies while others, e.g., from Pinus sylvestris, do not. Both species, Betula verrucosa and Pinus sylvestris are common in the northern parts of Europe and Asia, where Pinus sylvestris extents to some southern areas [6]. Pollen of Betula verrucosa has a spherical/triangular shape with a diameter of about 25 μm, while Pinus sylvestris has saccate pollen grains possessing a pair of air sacs, which leads to a maximum diameter of about 70 μm [8]. Further determinants include the solubility of the pollen derived allergens [9], the presence of microbial contaminants on the pollen surface [10] or chemical modifications of allergens [11] as consequence of air pollution [10]

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