Whelan, Kelly A. and Merves, Jamie F. and Giroux, Veronique and Tanaka, Koji and Guo, Andy and Chandramouleeswaran, Prasanna M. and Benitez, Benitez and Dods, Kara and Que, Jianwen and Masterson, Joanne C. and Fernando, Shahan D. and Godwin, Bridget C. and Klein-Szanto, Andres J. and Chikwava, Kudakwashe and Ruchelli, Eduardo D. and Hamilton, Kathryn E. and Muir, Amanda B. and Wang, Mei-Lun and Furuta, Glenn T. and Falk, Gary W. and Spergel, Jonathan M. and Nakagawa, Hiroshi (2017) Autophagy mediates epithelial cytoprotection in Eosinophilic Oesophagitis. Gut, 66 (7). pp. 1197-1207. ISSN 1468-3288

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Abstract

Objective—The influence of eosinophilic oesophagitis (EoE)-associated inflammation upon oesophageal epithelial biology remains poorly understood. We investigated the functional role of autophagy in oesophageal epithelial cells (keratinocytes) exposed to the inflammatory EoE milieu. Design—Functional consequences of genetic or pharmacological autophagy inhibition were assessed in endoscopic oesophageal biopsies, human oesophageal keratinocytes, single cell-derived ex vivo murine oesophageal organoids as well as a murine model recapitulating EoE-like inflammation and basal cell hyperplasia. Gene expression, morphological and functional characterization of autophagy and oxidative stress were performed by transmission electron microscopy, immunostaining, immunoblotting, live cell imaging and flow cytometry. Results—EoE-relevant inflammatory conditions promoted autophagy and basal cell hyperplasia in three independent murine EoE models and oesophageal organoids. Inhibition of autophagic flux via chloroquine treatment augmented basal cell hyperplasia in these model systems. Oesophageal keratinocytes stimulated with EoE-relevant cytokines, including tumor necrosis factor-α and interleukin-13 exhibited activation of autophagic flux in a reactive oxygen species-dependent manner. Autophagy inhibition via chloroquine treatment or depletion of Beclin-1 or ATG-7, augmented oxidative stress induced by EoE-relevant stimuli in murine EoE, oesophageal organoids and human oesophageal keratinocytes. Oesophageal epithelia of pediatric EoE patients with active inflammation displayed increased autophagic vesicle content compared to normal and EoE remission subjects. Functional flow cytometric analysis revealed autophagic flux in human oesophageal biopsies.Conclusions—Our findings reveal for the first time that autophagy may function as a cytoprotective mechanism to maintain epithelial redox balance and homeostasis under EoE inflammation-associated stress, providing mechanistic insights into the role of autophagy in EoE pathogenesis.

Item Type:	Article
Additional Information:	Author manuscript of published article, which is available at: Gut. 2017 July ; 66(7): 1197–1207. doi:10.1136/gutjnl-2015-310341.
Keywords:	Cell biology; Epithelial cells; Inflammation; Oesophagitis; Autophagy; Eosinophilic Oesophagitis; EoE; epithelial homeostasis; basal cell; oxidative stress;
Academic Unit:	Faculty of Science and Engineering > Biology Faculty of Science and Engineering > Research Institutes > Human Health Institute
Item ID:	11827
Identification Number:	https://doi.org/10.1136/gutjnl-2015-310341
Depositing User:	Joanne Masterson
Date Deposited:	18 Nov 2019 17:04
Journal or Publication Title:	Gut
Publisher:	BMJ Publishing Group
Refereed:	Yes
URI:
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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