Αρχειοθήκη ιστολογίου

Αλέξανδρος Γ. Σφακιανάκης
ΩτοΡινοΛαρυγγολόγος
Αναπαύσεως 5
Άγιος Νικόλαος Κρήτη 72100
2841026182
6032607174

Πέμπτη 15 Ιουνίου 2017

Histamine Receptor 2 Modifies iNKT Cell Activity within the Inflamed Lung

Abstract

Background

Histamine is a key immunoregulatory mediator and can dampen proinflammatory responses via activation of histamine receptor 2 (H2R). The aim of this study was to determine the role of H2R in modulating lung inflammatory responses.

Methods

H2R was blocked using famotidine or activated using dimaprit in both the ovalbumin (OVA) and house dust mite extract (HDM) murine models of respiratory inflammation. H2R-deficient animals and CD1d/ H2R-deficient animals were utilized to examine the CD1d presentation of lipid antigens (αGal-Cer or OCH) to invariant Natural Killer T (iNKT) cells.

Results

Famotidine treatment resulted in more severe airway disease in the OVA model, while dimaprit treatment significantly reduced disease severity. Both OVA and HDM-induced airway disease were more severe in H2R-deficient animals. Flow cytometric analysis of lung tissue from H2R-deficient animals revealed increased numbers of CD1d+ dendritic cells and increased numbers of iNKT cells. In vitro, αGal-Cer-stimulated iNKT cells from H2R-deficient mice secreted higher levels of IL-4, IL-5 and GM-CSF. In vivo, αGal-Cer or OCH administration to the lung resulted in enhanced mucus secretion, inflammatory cell recruitment and cytokine production in H2R-deficient or famotidine-treated animals, while dimaprit dampened the lung iNKT cell response to αGalCer. Removal of iNKT cells in H2R-deficient (CD1d-/-H2R-/-) animals normalized the lung response to HDM.

Conclusion

The deliberate activation of H2R, or its downstream signaling molecules, may represent a novel therapeutic target for chronic lung inflammatory diseases, especially when CD1d-mediated presentation of lipid antigens to iNKT cells are contributing to the pathology.

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