Impact of Urbanization on the Proteome of Birch Pollen and Its Chemotactic Activity on Human Granulocytes

Abstract

Background: Epidemiologic studies reveal a dramatic increase in allergies in the last decades. Air pollution is considered to be one of the factors responsible for this augmentation. The aim of this study was to analyze the impact of urbanization on birch pollen. The birch pollen proteome was investigated in order to identify differences in protein abundance between pollen from rural and urban areas. The allergenicity of birch pollen from both areas was evaluated by assessing its chemotactic potency as well as its protein and allergen contents. Methods: Difference gel electrophoresis (DIGE) was used to analyze the pollen proteome. The chemotactic activity of aqueous pollen extracts was determined by migration assays of human neutrophils. Results: DIGE revealed 26 differences in protein spot intensity between pollen from urban and rural areas. One of these proteins was identified by de novo sequencing as the 14-3-3 protein, which resembles a stress-induced factor in other plant species. Furthermore, extracts from pollen collected in urban areas had higher chemotactic activity on human neutrophils compared to pollen from rural sites. Conclusions: The present study points to an impact of air pollution on allergen carrier proteome and release of chemotactic substances. The increment in proinflammatory substances such as pollen-associated lipid mediators might contribute to the described urban-rural gradient of allergy prevalence. Furthermore, our study suggests that allergenicity is determined by more than the sole allergen content.

Ragweed pollen collected along high‐traffic roads shows a higher allergenicity than pollen sampled in vegetated areas

“…Other previous field-based experiments, which assessed the differences between pollen from rural and urban areas, provided divergent results. For instance, the amount of Lol p 5 in Lolium pollen was higher in urban areas (17), whereas Phl p 5 allergen was more abundant in pollen collected from rural areas (18), and the amount of Bet v 1 was similar in the two environments (19). In our opinion, the discrepancy among these results should be ascribed to the heterogeneity of the urban areas.…”

Variability ofCorylus Avellana, L. CorA and profilin pollen allergens expression

“…In samples from borders of the urbanized area was the expression of Betv1 allergen only 0.55 times higher when comparing to the forest sample. [17] Bryce et al [39] also reported that extracts from pollen collected within the trees in urban areas had higher chemotactic activity on human neutrophils compared to pollen from rural sites, although the allergen content remained unchanged.…”

Pollen metabolome analysis reveals adenosine as a major regulator of dendritic cell–primed TH cell responses

“…Birch pollen was also collected in the spring of 2009 during the birch-flowering season in southern Bavaria, as previously described. 22 For details on the preparation, ultrafiltration, and adenosine deaminase (ADA) digestion of APEs, see the Methods section in this article's Online Repository.…”