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A7164 - The Receptor for Advanced Glycation Endproducts Is a Critical Mediator of Type 2 Cytokine Signaling in Mice and Primary Human Cultures
Author Block: T. N. Perkins, R. E. Dutz, T. D. Oury; Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
Background: The receptor for advanced glycation endproducts (RAGE) is a critical mediator in the development of asthma and allergic airway inflammation (AAI). Previous studies showed that RAGE was required for IL-33 dependent accumulation of type 2 innate lymphoid cells (ILC2) and subsequent production of IL-5 and IL-13, which induce eosinophilic inflammation and mucus metaplasia. This study examines the role of RAGE in lung responsiveness to IL-5 and IL-13 and the downstream outcomes. Methods: Wild-type (WT) and RAGE-knockout (KO) mice were administered recombinant mouse Interleukin-5 and Interleukin-13 intranasally (i.n.) daily for 4 days, and sacrificed 24h after last i.n. administration. Bronchoalveolar lavage fluid (BALF) and whole lung homogenates (WLH) were assessed for markers of eosinophilic inflammation and mucus metaplasia by ELISA, and QRT-PCR. Airway eosinophilia was assessed by cytospin analysis and lung inflammation and mucus metaplasia were assessed by histological examination. Primary human bronchial epithelial air-liquid interface (ALI) cultures were administered saline (control) or hIL-13 in addition to DMSO (Vehicle), or RAGE-specific small molecule inhibitor, FPS-ZM1, twice every other day, for 4 days total and cultures were analyzed for markers of eosinophilic inflammation and mucus metaplasia.Results: IL-5 and IL-13 administration induced BALF eosinophilia, as well as increased Eotaxin and Eotaxin-2 levels in the BALF and WLH in WT mice. Moreover, IL-5 and IL-13 administration increased mRNA levels of Eotaxin, Eotaxin-2, Mbp, as well as Gob5, Muc5ac, and Muc5b in WT mice and histology showed peribronchiolar inflammation and positive PAS staining in the airways of WT mice. Strikingly, RAGE-KO mice were completely protected from effects of IL-5 and IL-13 administration. In primary human ALI cultures, treatment increased mRNA levels of Eotaxin-2, Eotaxin-3, Gob5, and Muc5ac as well as release of Eotaxin-2 into the basolateral media. However, treatment with the RAGE-antagonist, FPS-ZM1, significantly abrogated the effects of IL-13 treatment. Conclusions: This study demonstrates that RAGE is a critical mediator of IL-5 and IL-13 signaling in both mice as well as primary human explant cultures. Not only is RAGE required for initiation and propagation of IL-33 dependent mechanisms in experimental AAI, but it is also required for type 2 cytokine responsiveness, which induce the downstream end-points of eosinophilic inflammation and mucus metaplasia. The requirement of RAGE throughout the development of AAI suggests it may be a promising potential therapeutic target.