Project description:RationaleDNA methylation is an important epigenetic mechanism, which often occurs in response to environmental stimuli and is crucial in regulating gene expression. It is likely that epigenetic alterations contribute to pathogenesis in idiopathic pulmonary fibrosis (IPF).ObjectivesTo determine the DNA methylation changes in IPF and their effects on gene expression.MethodsTotal DNA methylation and DNA methyltransferase expression were compared in IPF and normal control lung tissues. IPF and normal tissues were subjected to comparative analysis of genome-wide DNA methylation and RNA expression using DNA hybridization to the Illumina HumanMethylation27 BeadChip and RNA hybridization to Illumina HumanHT-12 BeadChip. Functional analyses of differentially expressed and differentially methylated genes were done. Selected genes were validated at DNA, RNA, and protein levels.Measurements and main resultsDNA methylation status was altered in IPF. IPF samples demonstrated higher DNA methyltransferase expression without observed alterations in global DNA methylation. Genome-wide differences in DNA methylation status and RNA expression were demonstrated by array hybridization. Among the genes whose DNA methylation status and RNA expression were both significantly altered, 16 genes were hypermethylated in DNA associated with decreased mRNA expression or vice versa. We validated CLDN5, ZNF467, TP53INP1, and DDAH1 genes at the level of DNA methylation status, RNA, and protein-level expression.ConclusionsChanges in DNA methylation correspond to altered mRNA expression of a number of genes, some with known and others with previously uncharacterized roles in IPF, suggesting that DNA methylation is important in the pathogenesis of IPF.
Project description:Idiopathic Pulmonary Fibrosis (IPF) is a chronic progressive lung disease that affects more than 5 million people worldwide with a steady increase in both incidence and mortality. There is currently no effective therapy and the median survival without transplant is 2-5 years. The etiological factor is unknown, but several observational and pathogenesis studies suggest that environmental agents may cause IPF. DNA methylation is a type of chemical modification of DNA such environmental and occupational factors, that can induced a changes in the regulation of biological processes and link to diseases such as a cancer. We hypothesize that the global changes in methylation patterns of IPF lungs caused by environmental factors. In this study we will identify the global methylation signatures of the IPF lung and to compare to methylation signature of lung cancer. The DNA methylation profiles of IPF lung tissue differs from control lung but it shares great similarity with that of lung cancer.
Project description:Analysis of Idiopathic pulmonary fibrosis (IPF) at gene expression level. The hypothesis tested in the present study was that Epigenetic mechanisms are likely to be associated with pathogenesis in IPF. To determine the DNA methylation change, and their effects on gene expression, we compared microarray data of DNA methylation and RNA expression. Results provide that among the genes whose DNA methylation status and RNA expression were both significantly altered between IPF-rapid and normal controls.
Project description:BACKGROUND:Idiopathic Pulmonary Fibrosis (IPF) is characterized by profound changes in the lung phenotype including excessive extracellular matrix deposition, myofibroblast foci, alveolar epithelial cell hyperplasia and extensive remodeling. The role of epigenetic changes in determining the lung phenotype in IPF is unknown. In this study we determine whether IPF lungs exhibit an altered global methylation profile. METHODOLOGY/PRINCIPAL FINDINGS:Immunoprecipitated methylated DNA from 12 IPF lungs, 10 lung adenocarcinomas and 10 normal histology lungs was hybridized to Agilent human CpG Islands Microarrays and data analysis was performed using BRB-Array Tools and DAVID Bioinformatics Resources software packages. Array results were validated using the EpiTYPER MassARRAY platform for 3 CpG islands. 625 CpG islands were differentially methylated between IPF and control lungs with an estimated False Discovery Rate less than 5%. The genes associated with the differentially methylated CpG islands are involved in regulation of apoptosis, morphogenesis and cellular biosynthetic processes. The expression of three genes (STK17B, STK3 and HIST1H2AH) with hypomethylated promoters was increased in IPF lungs. Comparison of IPF methylation patterns to lung cancer or control samples, revealed that IPF lungs display an intermediate methylation profile, partly similar to lung cancer and partly similar to control with 402 differentially methylated CpG islands overlapping between IPF and cancer. Despite their similarity to cancer, IPF lungs did not exhibit hypomethylation of long interspersed nuclear element 1 (LINE-1) retrotransposon while lung cancer samples did, suggesting that the global hypomethylation observed in cancer was not typical of IPF. CONCLUSIONS/SIGNIFICANCE:Our results provide evidence that epigenetic changes in IPF are widespread and potentially important. The partial similarity to cancer may signify similar pathogenetic mechanisms while the differences constitute IPF or cancer specific changes. Elucidating the role of these specific changes will potentially allow better understanding of the pathogenesis of IPF.
Project description:Idiopathic Pulmonary Fibrosis (IPF) is a chronic progressive lung disease that affects more than 5 million people worldwide with a steady increase in both incidence and mortality. There is currently no effective therapy and the median survival without transplant is 2-5 years. The etiological factor is unknown, but several observational and pathogenesis studies suggest that environmental agents may cause IPF. DNA methylation is a type of chemical modification of DNA such environmental and occupational factors, that can induced a changes in the regulation of biological processes and link to diseases such as a cancer. We hypothesize that the global changes in methylation patterns of IPF lungs caused by environmental factors. In this study we will identify the global methylation signatures of the IPF lung and to compare to methylation signature of lung cancer. The DNA methylation profiles of IPF lung tissue differs from control lung but it shares great similarity with that of lung cancer. Immunoprecipitated methylated DNA from 12 IPF lungs, 10 lung adenocarcinomas and 10 normal histology lungs obtained from the same group of adenocarcinoma patients was hybridized to Agilent human CpG Islands Microarrays. Only probes with a hybridization Tm value between 79 C and 93C were included in the analysis because these show higher quality signal. All probes were divided according to their Tm into 14 groups/bins differing by 1C. Probe signals in each bin were standardized to have an average of 0 and a standard deviation of 1. To work in a CpG island oriented manner, we scored each island for its likelihood to be methylated. For that purpose, each probe was mapped to the genome and the signals of the probes that were mapped to a single CpG island were averaged to obtain the islandM-bM-^@M-^Ys methylation score. Data analysis was performed using BRB-Array Tools and DAVID Bioinformatics Resources software packages.
Project description:Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal lung disorder of unknown origin with a highly variable and unpredictable clinical course. Polymorphisms and environmentally induced epigenetic variations seem to determine individual susceptibility to the development of lung fibrosis.We have studied circulating epitopes on cell-free nucleosomes (cfnucleosomes) in 50 IPF patients. We have compared untreated IPF (n = 23) with IPF receiving antifibrotic therapy (n = 27) and healthy subjects (HS) (n = 27). We analyzed serum levels of five cfnucleosomes including bound HMGB1 (nucleosomes adducted to high-mobility growth protein B1), mH2A1.1 (nucleosomes containing the histone variant mH2A1.1), 5mC (nucleosomes associated with methylated DNA), and H3K9Ac and H3K27Ac (nucleosomes associated with histone H3 acetylated at lysine 9 or 27 residue).Our findings showed that serum levels of bound HMGB1, mH2A1.1, 5mC, H3K9Ac, and H3K27Ac were significantly lower in IPF patients than in HS (p < 0.001, p < 0.001, p < 0.01, p < 0.001, and p < 0.0001, respectively). Moreover, we found differences in epigenetic profiles between untreated IPF patients and those receiving anti-fibrotic therapy with mH2A1.1 and 5mC being significantly lower in untreated than in treated patients (p < 0.01 and p < 0.05, respectively). Combination of four cfnucleosomes (HMGB1, 5mC, H3K9Ac, and H3K27Ac) allow to discriminate IPF vs HS with a good coefficient of determination (R2 = 0.681). The AUC for the ROC curve computed by this logistic regression was 0.93 (p < 0.001) with 91% sensitivity at 80% specificity.Our observations showed that cfnucleosomes (bound HMGB1, mH2A1.1, 5mC, H3K9Ac, and H3K27Ac) might have potential as biomarkers for diagnosis and treatment response. These results deserve further validation in longitudinal cohorts.
Project description:Fibroblasts are the key effector cells in idiopathic pulmonary fibrosis (IPF), a chronic, progressive scarring disorder that results in impaired gas exchange and respiratory failure. Fibroblasts from IPF patients exhibit aberrant expression of multiple genes, but the DNA methylome of IPF fibroblasts has never been characterized. We utilized the HumanMethylation27 array, which assays the DNA methylation level of 27,568 CpG sites to compare the DNA methylation patterns of IPF fibroblasts (n=6) with those of nonfibrotic patient controls (n=3) and commercially available normal lung fibroblast cell lines (CCL190, CCL204, and CCL210). Multiple CpG sites across the genome were differentially methylated (as defined by P value less than 0.05 and fold change greater than 2) in IPF fibroblasts compared to fibroblasts from nonfibrotic controls. These methylation changes occurred in both genes recognized to be important in fibroproliferation and extracellular matrix generation, as well as in genes not previously recognized to participate in those processes (including organ morphogenesis and potassium ion channels). We used bisulfite sequencing to independently verify DNA methylation changes in 3 genes (CDKN2B, CARD10, and MGMT); these methylation changes corresponded with changes in gene expression at the mRNA and protein level. These changes in DNA methylation were stable throughout multiple cell passages. DNA methylation changes may thus help to explain a proportion of the differences in gene expression previously observed in studies of IPF fibroblasts. Moreover, significant variability in DNA methylation was observed among individual IPF cell lines, suggesting that differences in DNA methylation may contribute to fibroblast heterogeneity among patients with IPF. These results demonstrate that IPF fibroblasts exhibit global differences in DNA methylation that may contribute to the excessive fibroproliferation associated with this disease.