Project description:Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF), but are not good predictors of lung disease phenotype. Genome-wide association studies (GWAS) previously identified additional regions of the genome associated with CF disease severity. One of these, at chromosome 11p13, is an intergenic region between Ets homologous factor (EHF) and Apaf-1 interacting protein (APIP). Our goal was to determine the functional significance of this region, which is predicted to be regulatory, since it lacks annotated genes. To identify cis-regulatory elements within the chr11p13 region in lung epithelial cells, we first mapped open chromatin, using DNase I digestion and deep sequencing (DNase-seq). Next, histone modifications associated with active chromatin, H3K4me1 and H3K27ac, were revealed by chromatin immunoprecipitation. Predicted enhancer elements were assayed in bronchial epithelial cells using luciferase reporter genes. Two elements showed strong enhancer activity for the promoters of both EHF and the 5’ adjacent gene E47 like ETS transcription factor 5 (ELF5). No enhancers of the APIP promoter were found. Next, to determine direct physical interactions between cis-regulatory elements and gene promoters within 11p13 we used circular chromosome conformation capture (4C-seq). 4C-seq confirmed the enhancer-promoter associations, identified additional interacting elements and defined the boundaries of the topologically associated domains (TADs) at 11p13, which are enriched for CTCF. No strong interactions were observed with the APIP promoter, which lies outside of the main TAD encompassing the GWAS signal. These results focus attention on the role of EHF in modifying CF lung disease severity.
Project description:E74-like factor 5 (ELF5) and ETS-homologous factor (EHF) are epithelial selective ETS family transcription factors (TFs) encoded by genes at chr11p13, a region associated with cystic fibrosis (CF) lung disease severity. EHF controls many key processes in lung epithelial function so its regulatory mechanisms are important. Using CRISPR/Cas9 technology, we removed three cis-regulatory elements (CREs) from the chr11p13 region in airway epithelial cells. Deletion of two enhancers and one CRE within a stretch enhancer at the EHF locus caused subtle changes in chromatin architecture, and though EHF expression did not change, ELF5 abundance increased. ELF5 is normally very low in airway cells so we next examined cell types that express more ELF5 (LNCaP and T47D). ATAC-seq experiments in these lines revealed novel peaks of open chromatin (potential CREs) at the 5’ end of chr11p13 that were associated with an expressed ELF5 gene. Furthermore, 4C-seq assays identified direct interactions between the active ELF5 promoter and sites within the EHF locus, suggesting coordinate regulation between these TFs. ChIP-seq for ELF5 in T47D cells revealed ELF5 occupancy within EHF introns 1 and 6 and siRNA-mediated depletion of ELF5 repressed EHF expression. These results define a new role for ELF5 in lung epithelial biology.
Project description:Cystic fibrosis (CF) is an inherited, multi-system disease caused by dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, a ubiquitous ion channel important for epithelial hydration. A direct consequence of this dysfunction is impaired mucociliary clearance, chronic airway infection and a persistent neutrophilic inflammatory response that results in progressive loss of lung function, development of respiratory failure and premature death. Partial restoration of CFTR function is now possible for most CF patients through mutation specific CFTR modulators. Ivacaftor monotherapy produces significant clinical improvement in CF patients with the G511D mutation. Dual therapy, combining ivacaftor with lumacaftor or tezacaftor, results in modest clinical improvements in patients homozygous for F508del. More recently, triple therapy with elexacaftor/tezacaftor/ivacaftor (ETI) has led to dramatic improvements in lung function and quality of life in patients homozygous and heterozygous for F508del. Sputum proteomics is a powerful research technique capable of identifying important airway disease mechanisms by interrogating the proteome, an entire set of proteins within biological samples. It has confirmed the central role of neutrophilic immune dysregulation in CF and non-CF bronchiectasis, particularly involving the release of antimicrobial proteins and neutrophil-extracellular traps (NETs), and through impaired anti-inflammatory mechanisms. These processes produce distinct molecular signatures within the sputum proteome that become increasingly abnormal with chronic airway infection and progressive lung disease severity. In CF patients, airway and systemic inflammatory cytokines potentially related to these signatures reduce with the various forms of CFTR modulation. To date, no studies of ETI therapy in CF lung disease have assessed large-scale change in protein expression using untargeted proteomics. We hypothesised that ETI therapy would shift the sputum proteome toward health, potentially normalising airway biology in people with CF. The objectives of this study were to investigate changes in the CF sputum proteome with the introduction of ETI, correlate these with changes in clinical markers of disease severity, and make comparisons with the sputum proteome in healthy controls and in repeat samples from CF patients not suitable for ETI therapy. We also explored which molecular pathways associated with CF lung disease did not change with ETI.
Project description:Using the 450K BeadChIP, we profiled DNA methylation in nasal epithelial cells collected from CF patients homozygous for the CFTR p.Phe508del mutation and healthy controls. We replicated DNA methylation at CpG sites by pyrosequencing. Patients were stratified according to their lung function (forced expiratory volume in 1 second). Our study (i) points to the importance of genes responsible for the integrity of the epithelium and the inflammatory and immune responses to explain lung disease variability in CF, (ii) highlights new candidate genes potentially involved in lung disease severity, while it corroborates the role of known modifier genes, and (iii) suggests that CF-associated dynamic changes of DNA methylation are prominent in transcriptionally active genomic regions. Bisulphite converted DNA from the 48 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip
Project description:Heritable genetic variants modify cystic fibrosis (CF) clinical phenotypes, e.g., lung disease, age-of-onset of persistent Pseudomonas aeruginosa (P. aeruginosa), and meconium ileus (MI). Previous genome wide association studies (GWAS) have begun to inform the genetic architecture of CF phenotypes. Analyses of gene expression will complement GWAS, as demonstrated by analyses of gene expression in lymphoblastoid cell lines (LCLs) to identify disease-related pathophysiological processes for non-CF complex traits. In this study, global gene expression was measured in RNA from LCLs from 754 CF patients and analyzed for association with lung disease severity, age-of-onset of persistent P. aeruginosa pulmonary infection, and MI at birth. Each phenotype displayed distinct expression associations. Most pathways significantly associated with lung disease were related to membranes, vesicle traffic, and Golgi/endoplasmic reticulum (ER). Pathways containing HLA genes (Class I and II) were significantly associated with both lung and P. aeruginosa phenotypes, but they displayed qualitative differences between phenotypes. MI associated with pathways involving oxidative phosphorylation. The results support the concept that gene expression associated with heritable variation acts to modify phenotypes in CF. 754 samples were analyzed; 2 control samples were plated by Expression Analysis per plate and 1 pooled sample from the patient set was added to one well on each plate.
Project description:Genome-wide gene expression was measured in peripheral blood mononuclear cells (PBMCs) from patients with cystic fibrosis (CF) after treatment in vitro with the flagellin protein fliC, and/or synthetic peptide IDR-1018 to assess patterns of gene expression. The patterns of gene expression suggest that CF cells have a hyperinflammatory phenotype including dysfunctional autophagy processes. The synthetic peptide IDR-1018 attentuates this hyperinflammatory phenotype. Total RNA was obtained from PBMCs obtained from CF patients after treatment with the fliC flagellin protein (that is known to play a role in CF lung inflammation), and/or the peptide IDR-1018 that has anti-inflammatory properties. Comparison of genes and pathways affected by these treatments indicated the role of autophagy process in CF disease.
Project description:Heritable genetic variants modify cystic fibrosis (CF) clinical phenotypes, e.g., lung disease, age-of-onset of persistent Pseudomonas aeruginosa (P. aeruginosa), and meconium ileus (MI). Previous genome wide association studies (GWAS) have begun to inform the genetic architecture of CF phenotypes. Analyses of gene expression will complement GWAS, as demonstrated by analyses of gene expression in lymphoblastoid cell lines (LCLs) to identify disease-related pathophysiological processes for non-CF complex traits. In this study, global gene expression was measured in RNA from LCLs from 754 CF patients and analyzed for association with lung disease severity, age-of-onset of persistent P. aeruginosa pulmonary infection, and MI at birth. Each phenotype displayed distinct expression associations. Most pathways significantly associated with lung disease were related to membranes, vesicle traffic, and Golgi/endoplasmic reticulum (ER). Pathways containing HLA genes (Class I and II) were significantly associated with both lung and P. aeruginosa phenotypes, but they displayed qualitative differences between phenotypes. MI associated with pathways involving oxidative phosphorylation. The results support the concept that gene expression associated with heritable variation acts to modify phenotypes in CF.
Project description:Lung disease causes most of the morbidity and mortality in cystic fibrosis (CF). However, understanding its pathogenesis has been hindered by lack of an animal model with characteristic features of CF. To overcome this problem, we recently generated pigs with targeted CFTR genes. We now report that within months of birth, CF pigs spontaneously develop hallmark features of CF lung disease including airway inflammation, remodeling, mucus accumulation, and infection. Their lungs contained multiple bacterial species, suggesting an equal opportunity host defense defect. In humans, the temporal and/or causal relationships between inflammation and infection have remained uncertain. To investigate these processes, we studied newborn pigs. Their lungs showed no inflammation, but were less often sterile than controls. Moreover, after intrapulmonary bacterial challenge, CF pigs failed to eradicate bacteria as effectively as wild- type pigs. These results suggest that impaired bacterial elimination is the pathogenic event that initiates a cascade of inflammation and pathology in CF lungs. Finding that CF pigs have a bacterial host defense defect within hours of birth provides an exciting opportunity to further investigate pathogenesis and to test therapeutic and preventive strategies before secondary consequences develop. Pig model of human CF lung disease
Project description:Summary: CF patients homozygous for the DF08 DF08 genotype present a full range of phenotypic manifestations that exist within the pulmonary system. This project aims to identify candidate genes that influence the severity of pulmonary disease; Hypothesis: The goal is to find genes predictive of progression in CF. More information can be found at http://www.hopkins-genomics.org/cf/cf001/index.html
Project description:Cystic Fibrosis (CF) is associated with pathology in multiple tissues including the lung, digestive tract and reproductive system. Lung disease is primarily a post-natal event but other organs are affected before birth. Here we use the CF sheep model to investigate the initiation and progression of CF disease through gestation.