Epithelial HIF-1α/claudin-1 axis regulates barrier dysfunction in eosinophilic esophagitis
Joanne C. Masterson, … , Sean P. Colgan, Glenn T. Furuta
Joanne C. Masterson, … , Sean P. Colgan, Glenn T. Furuta
Published August 1, 2019; First published July 2, 2019
Citation Information: J Clin Invest. 2019;129(8):3224-3235. https://doi.org/10.1172/JCI126744.
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Research Article Gastroenterology

Epithelial HIF-1α/claudin-1 axis regulates barrier dysfunction in eosinophilic esophagitis

Abstract

Epithelial barrier dysfunction is a significant factor in many allergic diseases, including eosinophilic esophagitis (EoE). Infiltrating leukocytes and tissue adaptations increase metabolic demands and decrease oxygen availability at barrier surfaces. Understanding of how these processes impact barrier is limited, particularly in allergy. Here, we identified a regulatory axis whereby the oxygen-sensing transcription factor HIF-1α orchestrated epithelial barrier integrity, selectively controlling tight junction CLDN1 (claudin-1). Prolonged experimental hypoxia or HIF1A knockdown suppressed HIF-1α–dependent claudin-1 expression and epithelial barrier function, as documented in 3D organotypic epithelial cultures. L2-IL5OXA mice with EoE-relevant allergic inflammation displayed localized eosinophil oxygen metabolism, tissue hypoxia, and impaired claudin-1 barrier via repression of HIF-1α/claudin-1 signaling, which was restored by transgenic expression of esophageal epithelial-targeted stabilized HIF-1α. EoE patient biopsy analysis identified a repressed HIF-1α/claudin-1 axis, which was restored via pharmacologic HIF-1α stabilization ex vivo. Collectively, these studies reveal HIF-1α’s critical role in maintaining barrier and highlight the HIF-1α/claudin-1 axis as a potential therapeutic target for EoE.

Authors

Joanne C. Masterson, Kathryn A. Biette, Juliet A. Hammer, Nathalie Nguyen, Kelley E. Capocelli, Bejan J. Saeedi, Rachel F. Harris, Shahan D. Fernando, Lindsay B. Hosford, Caleb J. Kelly, Eric L. Campbell, Stefan F. Ehrentraut, Faria N. Ahmed, Hiroshi Nakagawa, James J. Lee, Eóin N. McNamee, Louise E. Glover, Sean P. Colgan, Glenn T. Furuta

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Figure 6

Genetic and pharmacologic stabilization of esophageal epithelial HIF-1α attenuates inflammation and barrier dysfunction in a mouse model of EoE via claudin-1 restoration.

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Genetic and pharmacologic stabilization of esophageal epithelial HIF-1α ...
(A) Triple-transgenic L2-IL5+/LSL-HIF1A-dPA+/+/K14Cre+ and Cre– control mice were exposed to OXA-induced esophagitis (n = 5–21) and assessed for histologic activity scores from H&E-stained tissues. Esophageal eosinophils were assessed using MBP immunohistochemistry and enumerated by MBP+ staining per HPF. Representative H&E photomicrographs. Scale bars: 20 μm. (B) Mice were assessed for claudin-1 protein by Western blot, quantified by densitometry, and CLDN1 mRNA by real-time RT-PCR. (C) GLUT1 and CLDN1 mRNA were assessed by real-time RT-PCR in cells exposed to DMOG (1 mM) over a time course (4, 18 hours) (n = 6). (D) Patients’ endoscopic esophageal pinch biopsies were obtained and treated ex vivo with DMOG (500 μM) for 24 hours. Biopsies were harvested and assessed for GLUT1 and CLDN1 mRNA by real-time RT-PCR (n = 6). Statistical significance was assessed using Students’ t test. *P < 0.05, **P < 0.01, ***P < 0.001. Data are expressed as means ± SEM and represent a minimum of 3 experiments.