Neutrophilic Archives - World Asthma Foundation

[Lipid derivative of benzylidene malononitrile AG490 attenuates airway inflammation of mice with neutrophilic asthma].

Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi. 2016 Jun;32(6):730-733

Authors: Zhang M, Nong G, Jiang M, Zhan W

Abstract
Objective To observe the effect of lipid derivative of benzylidene malononitrile AG490 on the airway inflammation in a mouse model of neutrophilic asthma (NA). Methods Fifty-four specific pathogen-free (SPF) female C57BL/6 mice were randomly divided into 3 groups: NA group, AG490-treated NA (NAAG) group, and normal control (NC) group, 18 mice in each group. The NA group and the NAAG group were sensitized by airway instillation of ovalbumin (OVA) and lipopolysaccharide (LPS) on day 0, 6 and 13. The NAAG group was injected with AG490 (500 ?g/mouse, i.p.) three times a week, from day 0 after the first sensitization, for 3 weeks. Mice were challenged on day 21, 22 for 1 hour/time with an aerosol of 10 g/L OVA. At 24 hours after the final challenge, bronchoalveolar lavage fluid (BALF) was collected. The total number and differential counts of nucleated cells and the percentage of each type were determined. HE staining and PAS staining was employed for observing the lung pathological changes. The percentages of Th17 cells and regulatory T cells (Treg) in the lung issue were determined by flow cytometry. The level of interleukin-17 (IL-17) in BALF was measured using ELISA. Results Compared with the NA group, the total number of nucleated cells, the percentage of neutrophils and the percentage of eosinophils in BALF in the NAAG group were obviously reduced; lung tissue pathologic changes were improved in the NAAG group; goblet cell hyperplasia and the level of IL-17 in BALF in the NAAG group were significantly down-regulated; the proportion of Treg in the lung increased and the proportion of Th17 cells in the lung decreased in the NAAG group. Conclusion After NA mice are treated with AG490 during the sensitization phase, the proportion of Treg in the lung would increase and the proportion of Th17 cells in the lung would decrease. AG490 could attenuate the airway inflammation in the mouse model of NA.

PMID: 27371836 [PubMed – as supplied by publisher]

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Endotoxin Exposure during Sensitization to Blomia tropicalis Allergens Shifts TH2 Immunity Towards a TH17-Mediated Airway Neutrophilic Inflammation: Role of TLR4 and TLR2.

PLoS One. 2013;8(6):e67115

Authors: Barboza R, Câmara NO, Gomes E, Sá-Nunes A, Florsheim E, Mirotti L, Labrada A, Alcântara-Neves NM, Russo M

Abstract
Experimental evidence and epidemiological studies indicate that exposure to endotoxin lipopolysaccharide (eLPS) or other TLR agonists prevent asthma. We have previously shown in the OVA-model of asthma that eLPS administration during alum-based allergen sensitization blocked the development of lung TH2 immune responses via MyD88 pathway and IL-12/IFN-? axis. In the present work we determined the effect of eLPS exposure during sensitization to a natural airborne allergen extract derived from the house dust mite Blomia tropicalis (Bt). Mice were subcutaneously sensitized with Bt allergens co-adsorbed onto alum with or without eLPS and challenged twice intranasally with Bt. Cellular and molecular parameters of allergic lung inflammation were evaluated 24 h after the last Bt challenge. Exposure to eLPS but not to ultrapure LPS (upLPS) preparation during sensitization to Bt allergens decreased the influx of eosinophils and increased the influx of neutrophils to the airways. Inhibition of airway eosinophilia was not observed in IFN-?deficient mice while airway neutrophilia was not observed in IL-17RA-deficient mice as well in mice lacking MyD88, CD14, TLR4 and, surprisingly, TLR2 molecules. Notably, exposure to a synthetic TLR2 agonist (PamCSK4) also induced airway neutrophilia that was dependent on TLR2 and TLR4 molecules. In the OVA model, exposure to eLPS or PamCSK4 suppressed OVA-induced airway inflammation. Our results suggest that B. tropicalis allergens engage TLR4 that potentiates TLR2 signaling. This dual TLR activation during sensitization results in airway neutrophilic inflammation associated with increased frequency of lung TH17 cells. Our work highlight the complex interplay between bacterial products, house dust mite allergens and TLR signaling in the induction of different phenotypes of airway inflammation.

PMID: 23805294 [PubMed – as supplied by publisher]

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