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 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 3

HIF-1α attenuation mediates esophageal epithelial barrier dysfunction and diminishes claudin-1 expression.

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HIF-1α attenuation mediates esophageal epithelial barrier dysfunction an...
(A and B) Esophageal epithelial cell lines were generated by shRNA-mediated HIF-1α suppression (HIF1A-KD) (A) and overexpression of a transcriptionally inactive dominant-negative HIF-1α variant (HIF1A-DN) (B). These cells and respective controls (scrambled shRNA [shCtrl] or empty vector [evCtrl]) were grown at ALI, and epithelial barrier (TEER) (n = 3) and paracellular permeability (3-kDa FITC-dextran flux) were measured in vitro (n = 5–7). (C) Patients’ endoscopic esophageal pinch biopsies were assessed for mRNA expression of an array of claudin genes (n = 10). (D) HIF1A-KD and HIF1A-DN cells were examined for the expression of transmembrane junctional molecules. The dashed line represents control cells normalized to 1-fold. Heatmaps generated from normalized data (n = 3). (E) Western blotting confirmed claudin-1 protein loss in HIF1A-KD and HIF1A-DN cells, quantified by densitometry (n = 3). (F) Esophageal epithelial cells exposed to a time course (4, 24, 48, 72 hours) of experimental hypoxia compared with duration-matched normoxic cells were assessed for claudin-1 protein by Western blot in whole-cell lysates, and CLDN1 mRNA by real-time RT-PCR (n = 3–6). Statistical significance was assessed using Students’ t test. *P < 0.05, **P < 0.01. Data are expressed as means ± SEM and represent a minimum of 3 experiments.