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Title: Epigenetic dysregulation of interleukin 8 (CXCL8) hypersecretion in cystic fibrosis airway epithelial cells

Abstract

Airway epithelial cells in cystic fibrosis (CF) overexpress Interleukin 8 (CXCL8) through poorly defined mechanisms. CXCL8 transcription is dependent on coordinated binding of CCAAT/enhancer binding protein (C/EBP)β, nuclear factor (NF)-κB, and activator protein (AP)-1 to the promoter. Here we show abnormal epigenetic regulation is responsible for CXCL8 overexpression in CF cells. Under basal conditions CF cells had increased bromodomain (Brd)3 and Brd4 recruitment and enhanced NF-κB and C/EBPβ binding to the CXCL8 promoter compared to non-CF cells due to trimethylation of histone H3 at lysine 4 (H3K4me3) and DNA hypomethylation at CpG6. IL-1β increased NF-κB, C/EBPβ and Brd4 binding. Furthermore, inhibitors of bromodomain and extra-terminal domain family (BET) proteins reduced CXCL8 production in CF cells suggesting a therapeutic target for the BET pathway. -- Highlights: •A regulatory mechanism of CXCL8 transcriptional control in CF airways is proposed. •There was an increased binding of NF-κB and C/EBPβ transcription factors. •There was enhanced recruitment of BET proteins to the CXCL8 promoter. •Epigenetic modifications are responsible for the aberrant CXCL8 transcription.

Authors:
; ; ;
Publication Date:
OSTI Identifier:
22598796
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 476; Journal Issue: 4; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; DNA; FIBROSIS; GENE REGULATION; HISTONES; LYMPHOKINES; LYSINE; PROMOTERS; TRANSCRIPTION; TRANSCRIPTION FACTORS

Citation Formats

Poghosyan, Anna, E-mail: pannagos@yahoo.com, Patel, Jamie K., Clifford, Rachel L., and Knox, Alan J., E-mail: alan.knox@nottingham.ac.uk. Epigenetic dysregulation of interleukin 8 (CXCL8) hypersecretion in cystic fibrosis airway epithelial cells. United States: N. p., 2016. Web. doi:10.1016/J.BBRC.2016.05.140.
Poghosyan, Anna, E-mail: pannagos@yahoo.com, Patel, Jamie K., Clifford, Rachel L., & Knox, Alan J., E-mail: alan.knox@nottingham.ac.uk. Epigenetic dysregulation of interleukin 8 (CXCL8) hypersecretion in cystic fibrosis airway epithelial cells. United States. doi:10.1016/J.BBRC.2016.05.140.
Poghosyan, Anna, E-mail: pannagos@yahoo.com, Patel, Jamie K., Clifford, Rachel L., and Knox, Alan J., E-mail: alan.knox@nottingham.ac.uk. Fri . "Epigenetic dysregulation of interleukin 8 (CXCL8) hypersecretion in cystic fibrosis airway epithelial cells". United States. doi:10.1016/J.BBRC.2016.05.140.
@article{osti_22598796,
title = {Epigenetic dysregulation of interleukin 8 (CXCL8) hypersecretion in cystic fibrosis airway epithelial cells},
author = {Poghosyan, Anna, E-mail: pannagos@yahoo.com and Patel, Jamie K. and Clifford, Rachel L. and Knox, Alan J., E-mail: alan.knox@nottingham.ac.uk},
abstractNote = {Airway epithelial cells in cystic fibrosis (CF) overexpress Interleukin 8 (CXCL8) through poorly defined mechanisms. CXCL8 transcription is dependent on coordinated binding of CCAAT/enhancer binding protein (C/EBP)β, nuclear factor (NF)-κB, and activator protein (AP)-1 to the promoter. Here we show abnormal epigenetic regulation is responsible for CXCL8 overexpression in CF cells. Under basal conditions CF cells had increased bromodomain (Brd)3 and Brd4 recruitment and enhanced NF-κB and C/EBPβ binding to the CXCL8 promoter compared to non-CF cells due to trimethylation of histone H3 at lysine 4 (H3K4me3) and DNA hypomethylation at CpG6. IL-1β increased NF-κB, C/EBPβ and Brd4 binding. Furthermore, inhibitors of bromodomain and extra-terminal domain family (BET) proteins reduced CXCL8 production in CF cells suggesting a therapeutic target for the BET pathway. -- Highlights: •A regulatory mechanism of CXCL8 transcriptional control in CF airways is proposed. •There was an increased binding of NF-κB and C/EBPβ transcription factors. •There was enhanced recruitment of BET proteins to the CXCL8 promoter. •Epigenetic modifications are responsible for the aberrant CXCL8 transcription.},
doi = {10.1016/J.BBRC.2016.05.140},
journal = {Biochemical and Biophysical Research Communications},
number = 4,
volume = 476,
place = {United States},
year = {Fri Aug 05 00:00:00 EDT 2016},
month = {Fri Aug 05 00:00:00 EDT 2016}
}
  • The pathophysiology of cystic fibrosis (CF) airway disease stems from mutations in the CF Transmembrane Conductance Regulator (CFTR) gene, leading to a chronic respiratory disease. Actin cytoskeleton is disorganized in CF airway epithelial cells, likely contributing to the CF-associated basic defects, i.e. defective chloride secretion and sodium/fluid hypersorption. In this work, we aimed to find whether this alteration could be pointed out by means of Atomic Force Microscopy (AFM) investigation, as roughness and Young's elastic module. Moreover, we also sought to determine whether disorganization of actin cytoskeleton is linked to hypersoption of apical fluid. Not only CFBE41o- (CFBE) cells, immortalizedmore » airway epithelial cells homozygous for the F508del CFTR allele, showed a different morphology in comparison with 16HBE14o- (16HBE) epithelial cells, wild-type for CFTR, but also they displayed a lack of stress fibers, suggestive of a disorganized actin cytoskeleton. AFM measurements showed that CFBE cells presented a higher membrane roughness and decreased rigidity as compared with 16HBE cells. CFBE overexpressing wtCFTR became more elongated than the parental CFBE cell line and presented actin stress fibers. CFBE cells absorbed more fluid from the apical compartment. Study of fluid absorption with the F-actin-depolymerizing agent Latrunculin B demonstrated that actin cytoskeletal disorganization increased fluid absorption, an effect observed at higher magnitude in 16HBE than in CFBE cells. For the first time, we demonstrate that actin cytoskeleton disorganization is reflected by AFM parameters in CF airway epithelial cells. Our data also strongly suggest that the lack of stress fibers is involved in at least one of the early step in CF pathophysiology at the levels of the airways, i.e. fluid hypersorption. - Highlights: • CF bronchial epithelial (CFBE) cells show a disorganized actin cytoskeleton. • CFBE cells present high roughness and low rigidity in the plasmamembrane. • CFTR overexpression changes morphology and actin organization. • CFBE cells absorb more apical fluid than wild type bronchial epithelial cells. • Fluid absorption is increased by disorganization of actin cytoskeleton.« less
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