The effect of lipoprotein-associated phospholipase A2 deficiency on pulmonary allergic responses in Aspergillus fumigatus sensitized mice
| Autor: | Stephen S. Wilson, Melane Fehrenbach, Angela Franciska Haczku, Steven A. Sheardown, Colin H. Macphee, Giulia Ravaioli, Blerina Kokalari, Imre G. Redai, Zhilong Jiang |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Respiratory System
Lp-PLA2 PAF-AH 030204 cardiovascular system & hematology Lp-PLA(2) Cardiorespiratory Medicine and Haematology Immunoglobulin E Inbred C57BL Aspergillus fumigatus Pathogenesis chemistry.chemical_compound Mice 0302 clinical medicine 2.1 Biological and endogenous factors Aetiology Knock-out mice Lung Mice Knockout 0303 health sciences biology respiratory system 1-Alkyl-2-acetylglycerophosphocholine Esterase 3. Good health Knockout mouse Respiratory lipids (amino acids peptides and proteins) IgE Airway inflammation Pulmonary and Respiratory Medicine Knockout Clinical Sciences 03 medical and health sciences Phospholipase A2 Animals Aspergillosis Platelet Activating Factor 030304 developmental biology lcsh:RC705-779 Platelet-activating factor Research Lipoprotein-associated phospholipase A2 Inflammatory and immune system Degranulation lcsh:Diseases of the respiratory system Pneumonia biology.organism_classification Asthma Mice Inbred C57BL chemistry Immunology biology.protein Mast cells |
| Zdroj: | Respiratory research, vol 13, iss 1 Respiratory Research Respiratory Research, Vol 13, Iss 1, p 100 (2012) |
| Popis: | Background Lipoprotein-associated phospholipase A2 (Lp-PLA2)/platelet-activating factor acetylhydrolase (PAF-AH) has been implicated in the pathogenesis of cardiovascular disease. A therapeutic targeting of this enzyme was challenged by the concern that increased circulating platelet activating factor (PAF) may predispose to or increase the severity of the allergic airway response. The aim of this study was to investigate whether Lp-PLA2 gene deficiency increases the risk of PAF and IgE-mediated inflammatory responses in vitro and in vivo using mouse models. Methods Lp-PLA2-/- mice were generated and back crossed to the C57BL/6 background. PAF-AH activity was measured using a hydrolysis assay in serum and bronchoalveolar lavage (BAL) samples obtained from mice. Aspergillus fumigatus (Af)-specific serum was prepared for passive allergic sensitization of mice in vivo and mast cells in vitro. β- hexosaminidase release was studied in bone marrow derived mast cells sensitized with Af-specific serum or DNP-IgE and challenged with Af or DNP, respectively. Mice were treated with lipopolysaccharide (LPS) and PAF intratracheally and studied 24 hours later. Mice were sensitized either passively or actively against Af and were studied 48 hours after a single intranasal Af challenge. Airway responsiveness to methacholine, inflammatory cell influx in the lung tissue and BAL, immunoglobulin (ELISA) and cytokine (Luminex) profiles were compared between the wild type (WT) and Lp-PLA2-/- mice. Results PAF-AH activity was reduced but not completely abolished in Lp-PLA2-/- serum or by in vitro treatment of serum samples with a high saturating concentration of the selective Lp-PLA2 inhibitor, SB-435495. PAF inhalation significantly enhanced airway inflammation of LPS treated WT and Lp-PLA2-/- mice to a similar extent. Sensitized WT and Lp-PLA2-/- bone-marrow derived mast cells released β-hexosaminidase following stimulation by allergen or IgE crosslinking to equivalent levels. Wild type and Lp-PLA2-/- mice responded to passive or active allergic sensitization by significant IgE production, airway inflammation and hyperresponsiveness after Af challenge. BAL cell influx was not different between these strains while IL-4, IL-5, IL-6 and eotaxin release was attenuated in Lp-PLA2-/- mice. There were no differences in the amount of total IgE levels in the Af sensitized WT and Lp-PLA2-/- mice. Conclusions We conclude that Lp-PLA2 deficiency in C57BL/6 mice did not result in a heightened airway inflammation or hyperresponsiveness after PAF/LPS treatment or passive or active allergic sensitization and challenge. |
| Databáze: | OpenAIRE |
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