title: HIF-dependent regulation of claudin-1 is central to intestinal epithelial tight junction integrity.
abstract: Intestinal epithelial cells (IECs) are exposed to profound fluctuations in oxygen tension and have evolved adaptive transcriptional responses to a low-oxygen environment. These adaptations are mediated primarily through the hypoxia-inducible factor (HIF) complex. Given the central role of the IEC in barrier function, we sought to determine whether HIF influenced epithelial tight junction (TJ) structure and function. Initial studies revealed that short hairpin RNA-mediated depletion of the HIF1β in T84 cells resulted in profound defects in barrier and nonuniform, undulating TJ morphology. Global HIF1α chromatin immunoprecipitation (ChIP) analysis identified claudin-1 (CLDN1) as a prominent HIF target gene. Analysis of HIF1β-deficient IEC revealed significantly reduced levels of CLDN1. Overexpression of CLDN1 in HIF1β-deficient cells resulted in resolution of morphological abnormalities and restoration of barrier function. ChIP and site-directed mutagenesis revealed prominent hypoxia response elements in the CLDN1 promoter region. Subsequent in vivo analysis revealed the importance of HIF-mediated CLDN1 expression during experimental colitis. These results identify a critical link between HIF and specific tight junction function, providing important insight into mechanisms of HIF-regulated epithelial homeostasis.
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: Bejan J
authors.initials: BJ
authors.lastname: Saeedi
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Kao
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: David A
authors.initials: DA
authors.lastname: Kitzenberg
authors.affiliation: Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Division of Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: Evgenia
authors.initials: E
authors.lastname: Dobrinskikh
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: Kayla D
authors.initials: KD
authors.lastname: Schwisow
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Section of Pediatric Gastroenterology, Hepatology and Nutrition, Gastrointestinal Eosinophilic Diseases Program, Department of Pediatrics, Digestive Health Institute, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: Joanne C
authors.initials: JC
authors.lastname: Masterson
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: Agnieszka A
authors.initials: AA
authors.lastname: Kendrick
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: Caleb J
authors.initials: CJ
authors.lastname: Kelly
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Bayless
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Department of Anesthesiology and Perioperative Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Kominsky
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: Eric L
authors.initials: EL
authors.lastname: Campbell
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: Kristine A
authors.initials: KA
authors.lastname: Kuhn
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Division of Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
authors.forename: Glenn T
authors.initials: GT
authors.lastname: Furuta
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 louise.glover@ucdenver.edu sean.colgan@ucdenver.edu.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Colgan
authors.affiliation: Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 louise.glover@ucdenver.edu sean.colgan@ucdenver.edu.
authors.forename: Louise E
authors.initials: LE
authors.lastname: Glover
mesh_terms: D047369:Chromatin Immunoprecipitation; D062445:Claudin-1 / Q000235:genetics*; D051793:Hypoxia-Inducible Factor 1 / Q000502:physiology*; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D015398:Signal Transduction; D019108:Tight Junctions / Q000378:metabolism / Q000502:physiology*; D015533:Transcriptional Activation
chemical_list: C568108:CLDN1 protein, human; D062445:Claudin-1; D051793:Hypoxia-Inducible Factor 1