scholarly journals An Unsupervised Learning Method for Disease Classification Based on DNA Methylation Signatures

2018 ◽  
Author(s):  
Mohammad Firouzi ◽  
Andrei Turinsky ◽  
Sanaa Choufani ◽  
Michelle T. Siu ◽  
Rosanna Weksberg ◽  
...  
Keyword(s):  
Dna Methylation ◽  
De Novo ◽  
Genetic Disorders ◽  
Single Gene ◽  
High Accuracy ◽  
Disease Classification ◽  
Mendelian Disease ◽  
Learning Method ◽  
Unsupervised Analysis ◽  
Genome Wide

Recent work has shown that genome-wide DNA methylation (DNAm) profiles can be used to discern signatures that can identify specific genetic disorders. These methods are especially effective at identifying single gene (Mendelian) disease, and methods to identify such signatures have been built by comparing methylation profiles of known disease versus control samples. These methods, however, have to-date been supervised, precluding the application of these methods to diseases with as-yet-unknown genetic cause. In this work, we tackle the problem of unsupervised disease classification based on DNAm signatures. Our method combines pre-filtration of the data to identify most promising methylation sites, clustering to identify co-varying sites, and an iterative method to further refine the signatures to build an effective clustering framework. We validate the proposed method on four diseases with known DNAm signatures (CHARGE, Kabuki, Sotos, and Weaver syndromes) and show high accuracy at determining the correct disease using unsupervised analysis. We also experiment with our approach on a novel dataset of patients with a clinical diagnosis of Autism, and illustrate the de novo identification of a specific subtype.

scholarly journals DNA Methylation and Intra-Clonal Heterogeneity: The Chronic Myeloid Leukemia Model

Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3587
Author(s):  
Benjamin Lebecque ◽  
Céline Bourgne ◽  
Véronique Vidal ◽  
Marc G. Berger
Keyword(s):  
Dna Methylation ◽  
Chronic Myeloid Leukemia ◽  
Fusion Protein ◽  
Myeloid Leukemia ◽  
Kinase Inhibitors ◽  
Single Gene ◽  
Clonal Heterogeneity ◽  
Sequencing Technologies ◽  
Genome Wide ◽  
The Impact

Chronic Myeloid Leukemia (CML) is a model to investigate the impact of tumor intra-clonal heterogeneity in personalized medicine. Indeed, tyrosine kinase inhibitors (TKIs) target the BCR-ABL fusion protein, which is considered the major CML driver. TKI use has highlighted the existence of intra-clonal heterogeneity, as indicated by the persistence of a minority subclone for several years despite the presence of the target fusion protein in all cells. Epigenetic modifications could partly explain this heterogeneity. This review summarizes the results of DNA methylation studies in CML. Next-generation sequencing technologies allowed for moving from single-gene to genome-wide analyses showing that methylation abnormalities are much more widespread in CML cells. These data showed that global hypomethylation is associated with hypermethylation of specific sites already at diagnosis in the early phase of CML. The BCR-ABL-independence of some methylation profile alterations and the recent demonstration of the initial intra-clonal DNA methylation heterogeneity suggests that some DNA methylation alterations may be biomarkers of TKI sensitivity/resistance and of disease progression risk. These results also open perspectives for understanding the epigenetic/genetic background of CML predisposition and for developing new therapeutic strategies.

scholarly journals Persistent epigenetic memory impedes rescue of the telomeric phenotype in human ICF iPSCs following DNMT3B correction

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Shir Toubiana ◽  
Miriam Gagliardi ◽  
Mariarosaria Papa ◽  
Roberta Manco ◽  
Maty Tzukerman ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Dna Methyltransferase ◽  
De Novo ◽  
Pharmacological Intervention ◽  
Icf Syndrome ◽  
Genome Wide ◽  
Mammalian Genomes ◽  
Induced Pluripotent ◽  
Methylation Patterns

DNA methyltransferase 3B (DNMT3B) is the major DNMT that methylates mammalian genomes during early development. Mutations in human DNMT3B disrupt genome-wide DNA methylation patterns and result in ICF syndrome type 1 (ICF1). To study whether normal DNA methylation patterns may be restored in ICF1 cells, we corrected DNMT3B mutations in induced pluripotent stem cells from ICF1 patients. Focusing on repetitive regions, we show that in contrast to pericentromeric repeats, which reacquire normal methylation, the majority of subtelomeres acquire only partial DNA methylation and, accordingly, the ICF1 telomeric phenotype persists. Subtelomeres resistant to de novo methylation were characterized by abnormally high H3K4 trimethylation (H3K4me3), and short-term reduction of H3K4me3 by pharmacological intervention partially restored subtelomeric DNA methylation. These findings demonstrate that the abnormal epigenetic landscape established in ICF1 cells restricts the recruitment of DNMT3B, and suggest that rescue of epigenetic diseases with genome-wide disruptions will demand further manipulation beyond mutation correction.

scholarly journals Transposable element expression in tumors is associated with immune infiltration and increased antigenicity

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yu Kong ◽  
Christopher M. Rose ◽  
Ashley A. Cass ◽  
Alexander G. Williams ◽  
Martine Darwish ◽  
...  
Keyword(s):  
Dna Methylation ◽  
De Novo ◽  
Computational Method ◽  
The Cancer Genome Atlas ◽  
Potential Consequence ◽  
Sequencing Data ◽  
Antiviral Responses ◽  
Genome Wide ◽  
Cancer Genome Atlas ◽  
Demethylation Agent

AbstractProfound global loss of DNA methylation is a hallmark of many cancers. One potential consequence of this is the reactivation of transposable elements (TEs) which could stimulate the immune system via cell-intrinsic antiviral responses. Here, we develop REdiscoverTE, a computational method for quantifying genome-wide TE expression in RNA sequencing data. Using The Cancer Genome Atlas database, we observe increased expression of over 400 TE subfamilies, of which 262 appear to result from a proximal loss of DNA methylation. The most recurrent TEs are among the evolutionarily youngest in the genome, predominantly expressed from intergenic loci, and associated with antiviral or DNA damage responses. Treatment of glioblastoma cells with a demethylation agent results in both increased TE expression and de novo presentation of TE-derived peptides on MHC class I molecules. Therapeutic reactivation of tumor-specific TEs may synergize with immunotherapy by inducing inflammation and the display of potentially immunogenic neoantigens.

scholarly journals Whole exome analysis of primary immunodeficiency

2018 ◽  
Vol 22 (5) ◽  
pp. 620-626
Author(s):  
E. S. Rahmani ◽  
Н. Azarpara ◽  
M. Karimipoor ◽  
Н. Rahimi
Keyword(s):  
Primary Immunodeficiency ◽  
Genetic Disorders ◽  
Single Gene ◽  
Correct Diagnosis ◽  
Severe Combined Immunodeficiency ◽  
Genetic Diagnosis ◽  
Cost Effective ◽  
Mendelian Disease ◽  
Inherited Disorders ◽  
Whole Exome

The human primary immunodeficiency diseases (PIDs) refer to a rare heterogeneous group of single-gene inherited disorders causing malfunctions in the immune system, and thus the affected patients have a predisposition to severe life-threatening infections. The heterogeneous nature of PIDs, which involves at list 300 different genes, makes diagnosis of the disease a complex issue. Although studies revealed that six million people have a kind of PID, but due to a complex diagnosis procedure many affected individuals have not gotten a correct diagnosis. However, thanks to advancing in the DNA sequencing method and availability of sophisticated sequencers molecular characterization of genetic disorders have been revolutionized. The whole exome sequencing (WES) method can help clinicians detect Mendelian disease and other complex genetic disorders. The presented study used WES to investigate two infants with symptoms of primary immunodeficiency including hemophagocytic lymphohistio­cytosis (HLH) and severe combined immunodeficiency (SCID). It has been shown that the HLH patient had a mutation in the UNC13D gene (NM_199242.2:c.627delT), and the SCID patient had a mutation in the RAG1 gene (NM_000448.2:c.322C>G). It has been demonstrated that WES is a fast and cost-effective method facilitating genetic diagnosis in PID sufferers.

scholarly journals Developmental Genome-Wide DNA Methylation Asymmetry Between Mouse Placenta and Embryo

2019 ◽  
Author(s):  
LM Legault ◽  
K Doiron ◽  
A Lemieux ◽  
M Caron ◽  
D Chan ◽  
...  
Keyword(s):  
Dna Methylation ◽  
De Novo ◽  
Prenatal Development ◽  
Methyltransferase Activity ◽  
Developmental Program ◽  
Genome Wide ◽  
Early Embryos ◽  
Somatic Tissues ◽  
Main Driver ◽  
Methylation Patterns

ABSTRACTIn early embryos, DNA methylation is remodelled to initiate the developmental program but for mostly unknown reasons, methylation marks are acquired unequally between embryonic and placental cells. To better understand this, we generated high-resolution DNA methylation maps of mouse mid-gestation (E10.5) embryo and placenta. We uncovered specific subtypes of differentially methylated regions (DMRs) that contribute directly to the developmental asymmetry existing between mid-gestation embryonic and placental DNA methylation patterns. We show that the asymmetry occurs rapidly during the acquisition of marks in the post-implanted conceptus (E3.5-E6.5), and that these patterns are long-lasting across subtypes of DMRs throughout prenatal development and in somatic tissues. We reveal that at the peri-implantation stages, the de novo methyltransferase activity of DNMT3B is the main driver of methylation marks on asymmetric DMRs, and that DNMT3B can largely compensate for lack of DNMT3A in the epiblast and extraembryonic ectoderm, whereas DNMT3A can only partially compensate in the absence of DNMT3B. However, as development progresses and as DNMT3A becomes the principal de novo methyltransferase, the compensatory DNA methylation mechanism of DNMT3B on DMRs becomes less effective.

scholarly journals Dppa2/4 Counteract De Novo Methylation to Establish a Permissive Epigenome for Development

2020 ◽  
Author(s):  
Kristjan H. Gretarsson ◽  
Jamie A. Hackett
Keyword(s):  
Dna Methylation ◽  
De Novo ◽  
Developmental Competence ◽  
Epigenetic Memory ◽  
Mammalian Development ◽  
Dna Hypomethylation ◽  
Lineage Specification ◽  
Regulatory Pathways ◽  
Genome Wide ◽  
Early Mammalian Development

ABSTRACTEarly mammalian development entails genome-wide epigenome remodeling, including DNA methylation erasure and reacquisition, which facilitates developmental competence. To uncover the mechanisms that orchestrate DNA methylation (DNAme) dynamics, we coupled a single-cell ratiometric DNAme reporter with unbiased CRISPR screening in ESC. We identify key genes and regulatory pathways that drive global DNA hypomethylation, and characterise roles for Cop1 and Dusp6. We also identify Dppa2 and Dppa4 as essential safeguards of focal epigenetic states. In their absence, developmental genes and evolutionary-young LINE1 elements, which DPPA2 specifically binds, lose H3K4me3 and gain ectopic de novo DNA methylation in pluripotent cells. Consequently, lineage-associated genes (and LINE1) acquire a repressive epigenetic memory, which renders them incompetent for activation during future lineage-specification. Dppa2/4 thereby sculpt the pluripotent epigenome by facilitating H3K4me3 and bivalency to counteract de novo methylation; a function co-opted by evolutionary young LINE1 to evade epigenetic decommissioning.

scholarly journals Epigenetic Deregulation of Protocadherin PCDHGC3 in Pheochromocytomas/Paragangliomas Associated With SDHB Mutations

2019 ◽  
Vol 104 (11) ◽  
pp. 5673-5692 ◽  
Author(s):  
Cristóbal Bernardo-Castiñeira ◽  
Nuria Valdés ◽  
Lucía Celada ◽  
Andrés San José Martinez ◽  
I Sáenz-de-Santa-María ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Promoter Methylation ◽  
De Novo ◽  
Gene Promoter ◽  
Gene Clusters ◽  
Suppressor Gene ◽  
Migration And Invasion ◽  
Primary Tumors ◽  
Genome Wide ◽  
Potential Biomarker

Abstract Context SDHB mutations are found in an increasing number of neoplasms, most notably in paragangliomas and pheochromocytomas (PPGLs). SDHB-PPGLs are slow-growing tumors, but ∼50% of them may develop metastasis. The molecular basis of metastasis in these tumors is a long-standing and unresolved problem. Thus, a better understanding of the biology of metastasis is needed. Objective This study aimed to identify gene methylation changes relevant for metastatic SDHB-PPGLs. Design We performed genome-wide profiling of DNA methylation in diverse clinical and genetic PPGL subtypes, and validated protocadherin γ-C3 (PCDHGC3) gene promoter methylation in metastatic SDHB-PPGLs. Results We define an epigenetic landscape specific for metastatic SDHB-PPGLs. DNA methylation levels were found significantly higher in metastatic SDHB-PPGLs than in SDHB-PPGLs without metastases. One such change included long-range de novo methylation of the PCDHA, PCDHB, and PCDHG gene clusters. High levels of PCDHGC3 promoter methylation were validated in primary metastatic SDHB-PPGLs, it was found amplified in the corresponding metastases, and it was significantly correlated with PCDHGC3 reduced expression. Interestingly, this epigenetic alteration could be detected in primary tumors that developed metastasis several years later. We also show that PCDHGC3 down regulation engages metastasis-initiating capabilities by promoting cell proliferation, migration, and invasion. Conclusions Our data provide a map of the DNA methylome episignature specific to an SDHB-mutated cancer and establish PCDHGC3 as a putative suppressor gene and a potential biomarker to identify patients with SDHB-mutated cancer at high risk of metastasis who might benefit from future targeted therapies.

QSER1 protects DNA methylation valleys from de novo methylation

Science ◽  
2021 ◽  
Vol 372 (6538) ◽  
pp. eabd0875 ◽  
Author(s):  
Gary Dixon ◽  
Heng Pan ◽  
Dapeng Yang ◽  
Bess P. Rosen ◽  
Therande Jashari ◽  
...  
Keyword(s):  
Dna Methylation ◽  
De Novo ◽  
Embryonic Stem ◽  
Central Question ◽  
Mammalian Development ◽  
Uncharacterized Gene ◽  
Pathological Conditions ◽  
Genome Wide ◽  
A Genome ◽  
De Novo Methylation

DNA methylation is essential to mammalian development, and dysregulation can cause serious pathological conditions. Key enzymes responsible for deposition and removal of DNA methylation are known, but how they cooperate to regulate the methylation landscape remains a central question. Using a knockin DNA methylation reporter, we performed a genome-wide CRISPR-Cas9 screen in human embryonic stem cells to discover DNA methylation regulators. The top screen hit was an uncharacterized gene, QSER1, which proved to be a key guardian of bivalent promoters and poised enhancers of developmental genes, especially those residing in DNA methylation valleys (or canyons). We further demonstrate genetic and biochemical interactions of QSER1 and TET1, supporting their cooperation to safeguard transcriptional and developmental programs from DNMT3-mediated de novo methylation.

scholarly journals Arsenic exposure in early pregnancy alters genome-wide DNA methylation in cord blood, particularly in boys

2014 ◽  
Vol 5 (4) ◽  
pp. 288-298 ◽  
Author(s):  
K. Broberg ◽  
S. Ahmed ◽  
K. Engström ◽  
M. B. Hossain ◽  
S. Jurkovic Mlakar ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Cord Blood ◽  
Mononuclear Cells ◽  
De Novo ◽  
Arsenic Exposure ◽  
Later Life ◽  
Linear Regression Models ◽  
Early Gestation ◽  
Cpg Sites ◽  
Genome Wide

Early-life inorganic arsenic exposure influences not only child health and development but also health in later life. The adverse effects of arsenic may be mediated by epigenetic mechanisms, as there are indications that arsenic causes altered DNA methylation of cancer-related genes. The objective was to assess effects of arsenic on genome-wide DNA methylation in newborns. We studied 127 mothers and cord blood of their infants. Arsenic exposure in early and late pregnancy was assessed by concentrations of arsenic metabolites in maternal urine, measured by high performance liquid chromatography-inductively coupled plasma mass spectrometry. Genome-wide 5-methylcytosine methylation in mononuclear cells from cord blood was analyzed by Infinium HumanMethylation450K BeadChip. Urinary arsenic in early gestation was associated with cord blood DNA methylation (Kolmogorov–Smirnov test, P-value<10–15), with more pronounced effects in boys than in girls. In boys, 372 (74%) of the 500 top CpG sites showed lower methylation with increasing arsenic exposure (rS-values>−0.62), but in girls only 207 (41%) showed inverse correlation (rS-values>−0.54). Three CpG sites in boys (cg15255455, cg13659051 and cg17646418), but none in girls, were significantly correlated with arsenic after adjustment for multiple comparisons. The associations between arsenic and DNA methylation were robust in multivariable-adjusted linear regression models. Much weaker associations were observed with arsenic exposure in late compared with early gestation. Pathway analysis showed overrepresentation of affected cancer-related genes in boys, but not in girls. In conclusion, early prenatal arsenic exposure appears to decrease DNA methylation in boys. Associations between early exposure and DNA methylation might reflect interference with de novo DNA methylation.

scholarly journals YAP contributes to DNA methylation remodeling upon mouse embryonic stem cell differentiation

2020 ◽  
pp. jbc.RA120.015896
Author(s):  
Fabiana Passaro ◽  
Ilaria De Martino ◽  
Federico Zambelli ◽  
Giorgia Di Benedetto ◽  
Matteo Barbato ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Target Genes ◽  
De Novo ◽  
Embryonic Stem ◽  
Mouse Embryonic Stem Cell ◽  
Stem Cell Differentiation ◽  
Embryonic Stem Cell Differentiation ◽  
Nucleosome Remodeling ◽  
Genome Wide ◽  
A Genome

The Yes-associated protein YAP, one of the major effectors of the Hippo pathway together with its related protein TAZ, mediates a range of cellular processes from proliferation and death to morphogenesis. YAP and TAZ regulate a large number of target genes, acting as co-activators of DNA-binding transcription factors or as negative regulators of transcription by interacting with the nucleosome remodeling and histone deacetylase complexes. YAP is expressed in self-renewing embryonic stem cells (ESCs), although it is still debated whether it plays any crucial roles in the control of either stemness or differentiation. Here we show that the transient downregulation of YAP in mouse ESCs perturbs cellular homeostasis, leading to the inability to differentiate properly. Bisulfite genomic sequencing revealed that this transient knockdown caused a genome-wide alteration of the DNA methylation remodeling that takes place during the early steps of differentiation, suggesting that the phenotype we observed might be due to the dysregulation of some of the mechanisms involved in regulation of ESC exit from pluripotency. By gene expression analysis we identified two molecules which could have a role in the altered genome-wide methylation profile: the long non-coding RNA Ephemeron, whose rapid upregulation is crucial for ESCs transition into epiblast, and the methyltransferase-like protein Dnmt3l, which, during the embryo development, cooperates with Dnmt3a and Dnmt3b to contribute to the de novo DNA methylation that governs early steps of ESC differentiation. These data suggest a new role for YAP in the governance of the epigenetic dynamics of exit from pluripotency.

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