scholarly journals Hypo-methylation mediates chromosomal instability in pancreatic NET

2017 ◽  
Vol 24 (3) ◽  
pp. 137-146 ◽  
Author(s):  
I Marinoni ◽  
A Wiederkeher ◽  
T Wiedmer ◽  
S Pantasis ◽  
A Di Domenico ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Chromosomal Instability ◽  
Global Dna Methylation ◽  
Epigenetic Changes ◽  
Knock Down ◽  
Alternative Lengthening ◽  
Increased Risk ◽  
Pancreatic Net ◽  
G0 Phase

DAXX and or ATRX loss occur in 40% of pancreatic neuroendocrine tumors (PanNETs). PanNETs negative for DAXX or ATRX show an increased risk of relapse. The tumor-associated pathways activated upon DAXX or ATRX loss and how this event may induce chromosomal instability (CIN) and alternative lengthening telomeres (ALT) are still unknown. Both DAXX and ATRX are involved in DNA methylation regulation. DNA methylation of heterochromatin and of non-coding sequences is extremely important for the maintenance of genomic stability. We analyzed the association of DAXX and/or ATRX loss and CIN with global DNA methylation in human PanNET samples and the effect of DAXX knock-down on methylation and cell proliferation. We assessedLINE1as well as global DNA methylation in 167 PanNETs, and we found that DAXX and or ATRX-negative tumors and tumors with CIN were hypomethylated. DAXX knock-down in PanNET cell lines blocked cells in G1/G0 phase and seemed to increase CIN in QGP-1 cells. However, no direct changes in DNA methylation were observed after DAXX knock-downin vitro. In conclusion, our data indicate that epigenetic changes are crucial steps in the progression of PanNETs loss and suggest that DNA methylation is the mechanism via which CIN is induced, allowing clonal expansion and selection.

scholarly journals Oxidative stress underlies heritable impacts of paternal cigarette smoke exposure

2019 ◽  
Author(s):  
Patrick J Murphy ◽  
Jingtao Guo ◽  
Timothy G Jenkins ◽  
Emma R James ◽  
John R Hoidal ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Dna Methylation ◽  
Cigarette Smoke ◽  
Cigarette Smoke Exposure ◽  
Epigenetic Changes ◽  
Sperm Dna ◽  
Increased Risk ◽  
Paternal Smoking ◽  
Sperm Dna Methylation

SUMMARYPaternal cigarette smoke (CS) exposure is associated with increased risk of behavioral disorders and cancer in offspring, but the mechanism has not been identified. This study used mouse models to evaluate: 1) what impact paternal CS exposure has on sperm DNA methylation (DNAme), 2) whether sperm DNAme changes persist after CS exposure ends, 3) the degree to which DNAme and gene expression changes occur in offspring and 4) the mechanism underlying impacts of CS exposure. We demonstrate that CS exposure induces sperm DNAme changes that are partially corrected within 28 days of removal from CS exposure. Additionally, paternal smoking causes changes in neural DNAme and gene expression in offspring. Remarkably, the effects of CS exposure are largely recapitulated in oxidative stress-compromised Nrf2-/- mice and their offspring, independent of paternal smoking. These results demonstrate that paternal CS exposure impacts offspring phenotype and that oxidative stress underlies CS induced heritable epigenetic changes.

scholarly journals Global DNA methylation: role, status and genome-wide approaches to study epigenetic mark in cloned embryos

2020 ◽  
pp. 41-59
Author(s):  
Shivani Malpotra ◽  
Ahmad Hussain
Keyword(s):  
Dna Methylation ◽  
Developmental Stages ◽  
Gene Expression Pattern ◽  
Methylation Profile ◽  
Global Dna Methylation ◽  
Epigenetic Mark ◽  
Dna Methylation Profile ◽  
Low Efficiency

Somatic cell nuclear transfer (SCNT) technique has been proving its worth for more than two decades now as over 20 different species have been successfully cloned. SCNT protocol for cloning is well established but efficiency in terms of live birth rate is still low. Epigenetic abnormality following nuclear reprogramming is considered as the main culprit behind its low efficiency. DNA methylation is one of the most important epigenetic modifications that directly or indirectly regulate gene expression pattern, development and genome stability. Embryos produced through SCNT are found to express abnormal DNA methylation profile in comparison with in vivo or in vitro produced embryos. In order to improve DNA methylation profile in cloned embryos, a complete database of whole genome is required to find out specific faulty targets. Many techniques including low throughput and high throughput approach has been used to profile DNA methylation pattern in bovine embryos throughout the developmental stages. In the present review, we have compiled the overall status of global DNA methylation, the effect of aberrant DNA methylation on development and evolution in methodologies used for profiling global DNA methylome in cloned embryos.

scholarly journals Alterations in CNS Functions and DNA Methylation in Rats after 24 h Exposure to Peat Smoke

Toxics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 342
Author(s):  
Vera A. Vokina ◽  
Larisa M. Sosedova ◽  
Mikhail A. Novikov ◽  
Viktor S. Rukavishnikov ◽  
Ekaterina A. Kapustina ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Blood Cells ◽  
Combustion Products ◽  
Albino Rats ◽  
Global Dna Methylation ◽  
Bioelectrical Activity ◽  
Epigenetic Changes ◽  
Behavioral Disturbances ◽  
Natural Fire ◽  
Peat Smoke

The use of a developed experimental model of a natural fire made it possible to assess the consequences of 24 h exposure to peat combustion products in albino rats. Peat smoke exposure leads to behavioral disturbances in rats, characterized by an increase in locomotor activity and an increased level of anxiety. Indicators of brain bioelectrical activity of the exposed animals supported the state of anxiety and psychoemotional stress. Epigenetic changes in the blood cells of exposed animals were revealed under 24 h exposure to peat smoke, characterized by a decrease in the level of global DNA methylation.

scholarly journals Διερεύνηση μηχανισμών χρωμοσωμικής αστάθειας και τελομερικής ομοιόστασης κατά την επαγωγή καρκινικών βλαστικών κυττάρων in vitro και in vivo

2019 ◽  
Author(s):  
Φανή-Μάρλεν Ρουμελιώτη
Keyword(s):  
Chromosomal Instability ◽  
Alternative Lengthening Of Telomeres ◽  
Alternative Lengthening

Ως χρωμοσωμική αστάθεια στη νεοπλασία (CIN-Chromosomal Instability in Neoplasia) ορίζεται ο αυξημένος ρυθμός συνεχών απωλειών ή διπλασιασμών ολόκληρων χρωμοσωμάτων ή μεγάλων τμημάτων τους κατά την κακοήθη κυτταρική ανάπτυξη. Η χρωμοσωμική αστάθεια είναι πολύ συχνή στη νεοπλασία (παρατηρείται περίπου στο 90% των συμπαγών όγκων και σε πολλές αιματολογικές κακοήθειες). Η CIN είναι συνεχής διαδικασία, διότι κατά την εξέλιξη της νόσου, ενισχύεται διαρκώς από την έκθεση των πολλαπλασιαζόμενων νεοπλασματικών κυττάρων σε τελομερική δυσλειτουργία, στρες αντιγραφής, ανεπάρκεια των σημείων ελέγχου του κυτταρικού κύκλου κύκλου και διαταραχές της μιτωτικής ατράκτου. Η τελομερική δυσλειτουργία και πως αυτή επηρεάζει τη χρωμοσωμική αστάθεια, είναι το κύριο θέμα έρευνας της παρούσας διατριβής. Τα τελομερή είναι εξειδικευμένες δομές που παίζουν σημαντικό ρόλο στη σταθερότητα του χρωμοσώματος. Η διασφάλιση της λειτουργικής και δομικής ακεραιότητάς τους έχει ζωτική σημασία για τη φυσιολογική και παθολογική κυτταρική λειτουργία. Η ικανότητα συνεχούς κυτταρικού πολλαπλασιασμού στον καρκίνο είναι άμεσα εξαρτώμενη από την ενεργοποίηση των μηχανισμών αναπλήρωσης των τελομερών. Στις νεοπλασίες των θηλαστικών, το μήκος των τελομερών ανανεώνεται κυρίως από το ένζυμο τελομεράση (TERT) ή σπανιότερα μέσω της εναλλακτικής επιμήκυνσης των τελομερών (alternative lengthening of telomeres-ALT). Στην ανθρώπινη νεοπλασία, ο συνεχής κυτταρικός πολλαπλασιασμός απουσία τελομεράσης (ALT) χαρακτηρίζεται από υψηλούς ρυθμούς δομικής αστάθειας των χρωμοσωμάτων. Αυτό οφείλεται στο ότι τα χρωμοσώματα των ALT καρκινικών κυττάρων δε διαθέτουν επαρκή τελομερική προστασία και είναι συχνά επιδεκτικά σε τυχαίες τελομερικές συντήξεις. Οι συντήξεις των τελομερών οδηγούν σε φαινόμενα γενικευμένης γενωμικής αστάθειας και οδηγούν σε ανασυνδυασμούς μεταξύ χρωμοσωμάτων οι οποίες ενεργοποιούν ή καταστέλλουν αντίστοιχα, ογκογόνα ή ογκοκατασταλτικά γονίδια. Τα νεοπλασματικά κύτταρα που χρησιμοποιούν τον ALT μηχανισμό επιμήκυνσης των τελομερών παρουσιάζουν 5 φορές αυξημένη συχνότητα χρωμοσωμικής αστάθειας σε σχέση με αυτά που χρησιμοποιούν την τελομεράση.Σκοπός της παρούσας διδακτορικής διατριβής είναι η διερεύνηση μηχανισμών δημιουργίας ανευπλοειδίας και πολυπλοειδίας κατά την εξέλιξη ALT καρκινικών κυττάρων σε συνθήκες γενοτοξικού στρες και στρες της αντιγραφής, σε μια προσπάθεια συμβολής στην κατανόηση της χρωμοσωμικής αστάθειας προς την ανάπτυξη νέων, αποτελεσματικότερων προγνωστικών διαγνωστικών ή ογκοθεραπευτικών μεθόδων.

scholarly journals O6D.2 Evidence of dna methylation changes by carbon nanotubes in a translational study design

2019 ◽  
Vol 76 (Suppl 1) ◽  
pp. A57.2-A57
Author(s):  
Manosij Ghosh ◽  
Deniz Öner ◽  
Lode Godderis ◽  
Peter Hoet
Keyword(s):  
Dna Methylation ◽  
Cross Sectional Study ◽  
Methylation Pattern ◽  
Global Dna Methylation ◽  
Limited Information ◽  
Cross Sectional ◽  
Translational Study ◽  
Exposed Workers

IntroductionWhile studies have addressed genotoxic effects of CNT, only limited information are available on epigenetic effects. We designed a study to investigate DNA methylation alterations in vitro, in vivo and in occupationally exposed workers.Material and methodsIn vitro studies were performed in 16-HBE and THP-1 cells. For the in vivo study, BALB/c mice were administered intratracheally with single-wall CNT (SWCNTs) and multi-wall (MWCNTs) at high (2.5 mg/kg) and low (0.25 mg/kg) doses. For the cross sectional study, 24 workers exposed to aggregates of MWCNT of 500 nm–100 µm with concentrations of 4.6–42.6 µg/m3 and 43 unexposed referents were recruited. Global DNA methylation and demethylation patterns were analysed by LC-MS/MS. Methylation of specific genes was measured by Pyromark 24® (Qiagen). Genome-wide assessment of DNA methylation was performed with Infinium HumanMethylation450 BeadChip Array.ResultsIn general, we did not find global DNA methylation alteration for both CNTs. In 16-HBE cells, differentially methylated and expressed genes (MWCNTs>SWCNTs) from p53 signalling, DNA damage repair and cell cycle pathways were observed. In THP-1 cells, CNTs induced promoter-specific methylation of genes involved in several signaling cascade, vascular endothelial growth factor and platelet activation pathways. In lungs of BALB/c mice CNTs affected methylation of ATM gene. Finally, analysis of gene-specific DNA methylation in exposed workers revealed significant changes for DNMT1, ATM, SKI, and HDAC4 promoter CpGs.ConclusionsEpigenetic changes seem to occur at sub cyto-genotoxic concentrations in vitro. Alteration in DNA methylation pattern could be a natural reaction of cells but could also silence critical genes and reprogram cellular functions.

scholarly journals Assessment of DNA Methylation and Oxidative Changes in the Heart and Brain of Rats Receiving a High-Fat Diet Supplemented with Various Forms of Chromium

Animals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1470
Author(s):  
Wojciech Dworzański ◽  
Ewelina Cholewińska ◽  
Bartosz Fotschki ◽  
Jerzy Juśkiewicz ◽  
Piotr Listos ◽  
...  
Keyword(s):  
Dna Methylation ◽  
High Fat Diet ◽  
Protein Carbonyl ◽  
Global Dna Methylation ◽  
Standard Diet ◽  
Epigenetic Changes ◽  
Oxidation Reactions ◽  
High Fat ◽  
Repair Enzymes ◽  
The Brain

The aim of the study was to determine how feeding rats a high-fat diet supplemented with various forms of chromium affects DNA methylation and oxidation reactions as well as the histology of heart and brain tissue. The rats received standard diet or high-fat diet and chromium at 0.3 mg/kg body weight (BW) in form of chromium (III) picolinate, chromium (III)-methionine, or nano-sized chromium. The content of malondialdehyde (MDA), protein carbonyl (PC), and 8-hydroxydeoxyguanosine (8-OHDG), the level of global DNA methylation and the activity of selected DNA repair enzymes were determined in the blood. In the brain and heart, the content of MDA, PC, 8-OHDG, and levels of global DNA methylation were determined. The brain was subjected to histological examination. The use of a high-fat diet was found to intensify epigenetic changes and oxidation reactions in the heart and brain. It was concluded that epigenetic changes and oxidation of lipids, proteins, and DNA in the heart and brain of rats resulting from the use of a high-fat diet cannot be limited by supplementing the diet with chromium. It was established that the use of chromium to supplement a high-fat diet intensifies the negative epigenetic and oxidative changes in the heart and brain, especially in the case of chromium nanoparticles.

DNMT3B Expression Delays Leukemogenesis,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3446-3446
Author(s):  
Petra Tschanter ◽  
Isabell Schulze ◽  
Nicole Bäumer ◽  
Beate Surmann ◽  
Konstantin Agelopoulos ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Malignant Disease ◽  
Bone Marrow Cells ◽  
Dna Methyltransferases ◽  
Leukemic Cells ◽  
Epigenetic Changes ◽  
Leukemia Development ◽  
The Impact ◽  
Dnmt3b Expression

Abstract Abstract 3446 Acute myeloid leukaemia (AML) is a malignant disease with poor prognosis, which is, among other biological features, characterized by epigenetic changes including alterations in DNA methylation. DNA methyltransferases (DNMT) play an important role in regulation of DNA methylation and mutations of DNMT3A are frequently found in AML. We analyzed the effects of DNMT overexpression on leukemogenesis using an inducible DNMT3B mouse model (Linhart et al., 2007). To analyse the impact of DNMT3B overexpression on leukemia we retrovirally co-transduced lineage-negative bone marrow cells of wildtype and DNMT3Btg mice with a MSCV-cMyc-bcl2 and a MSCV-tTA-GFP containing vector. Under these conditions, doxycycline suppressed DNMT3B expression whereas absence of doxycycline led to overexpression of DNMT3B on the mRNA and protein level. DNMT3B overexpression was not toxic since colony formation in vitro did not differ between DNMT3B expressing and physiologically expressing cells. To analyze leukemogenesis, 5 × 104 sorted GFP-positive cells were transplanted into sublethally irradiated wildtype recipients. Both recipients of transduced wildtype cells and recipients of transduced DNMT3Btg cells developed leukemia with a tendency of delayed leukemogenesis in DNMT3B overexpressing mice. GFP positive leukemic cells were sorted and doxycycline regulated DNMT3B expression was verified by Western blot analysis in vitro. To determine the repopulation capacity of the leukemic cells we performed transplantation of GFP-positive primary leukemia cells into secondary wildtype recipients. Leukemia of both, wildtype and DNMT3B-overexpressing donors was transplantable and lethal. However, DNMT3Btg leukemic cells were severely impaired in leukemia development in secondary recipients. Secondary recipients of leukemic DNMT3Btg cells died significantly later (p= 0.02). Taken together, these findings demonstrate that DNMT3B expression impairs leukemia maintenance. Loss of DNMT activity might contribute to the pool size of leukemia initiating cells. Disclosures: Krug: Boehringer Ingelheim: Research Funding.

scholarly journals Abnormal lipid metabolism in metabolic syndrome: an epigenetic perspective

2016 ◽  
Vol 24 (2) ◽  
pp. 153-160 ◽  
Author(s):  
Ioana Brudașcă ◽  
Mircea Cucuianu
Keyword(s):  
Metabolic Syndrome ◽  
Dna Methylation ◽  
Life Span ◽  
Maternal Obesity ◽  
Maternal Nutrition ◽  
Hdl Cholesterol ◽  
Atherogenic Dyslipidemia ◽  
Epigenetic Changes ◽  
The Metabolic Syndrome ◽  
Increased Risk

Abstract Metabolic syndrome is a complex pathology including central obesity, impaired glucose tolerance/diabetes, an atherogenic dyslipidemia and a prothrombotic state. A new perspective on understanding the mechanisms underlying metabolic syndrome is provided by the epigenetic changes (mainly DNA methylation and histone covalent modifications), which influence gene expression without changing of the DNA sequence. DNA methylation (mainly in carnitine palmitoyltransferase 1A gene) and histone modifications were shown to be associated with VLDL and LDL phenotypes, with hyperglycemia and reduced level of HDL cholesterol, with hypertriglyceridemic waist phenotype and with progression of atherosclerotic occlusion in peripheral arteries. The epigenetic changes can occur in the prenatal period, throughout the life span, and can be transmitted to the offspring. Both poor maternal nutrition and maternal obesity, diabetes and overfeeding can result in epigenetic alterations that amplify the risk of metabolic syndrome for the offspring. Throughout life span, environmental factors, such as nutrition and exercise can induce epigenetic changes influencing the evolution of the metabolic syndrome (through adipocyte metabolism and insulin signaling pathway). The epigenetic modifications are not completely erased during gametogenesis and embryogensis, resulting in a transgenerational transmission of an epigenetic state up to the fifth generation. Epigenetic mechanisms are an interface between environmental stimuli and resulting phenotype by inducing a certain transcriptional state, which may be also transmitted to the next generation(s) and which may predispose to an increased risk for developing metabolic syndrome in the context of a mismatched environment. Elucidating epigenetic modulation might provide additional information about risk evaluation and more targeted therapeutical intervention.

DNA methylation profile of liver of mice conceived by in vitro fertilization

2021 ◽  
pp. 1-9
Author(s):  
Saúl Lira-Albarrán ◽  
Xiaowei Liu ◽  
Seok Hee Lee ◽  
Paolo Rinaudo
Keyword(s):  
Dna Methylation ◽  
Enrichment Analysis ◽  
Functional Enrichment Analysis ◽  
Functional Enrichment ◽  
Global Dna Methylation ◽  
Analysis Tool ◽  
Gene Promoters ◽  
Vitro Fertilization ◽  
Natural Mating

Abstract Offspring generated by in vitro fertilization (IVF) are believed to be healthy but display a possible predisposition to chronic diseases, like hypertension and glucose intolerance. Since epigenetic changes are believed to underlie such phenotype, this study aimed at describing global DNA methylation changes in the liver of adult mice generated by natural mating (FB group) or by IVF. Embryos were generated by IVF or natural mating. At 30 weeks of age, mice were sacrificed. The liver was removed, and global DNA methylation was assessed using whole-genome bisulfite sequencing (WGBS). Genomic Regions for Enrichment Analysis Tool (GREAT) and G:Profilerβ were used to identify differentially methylated regions (DMRs) and for functional enrichment analysis. Overrepresented gene ontology terms were summarized with REVIGO, while canonical pathways (CPs) were identified with Ingenuity® Pathway Analysis. Overall, 2692 DMRs (4.91%) were different between the groups. The majority of DMRs (84.92%) were hypomethylated in the IVF group. Surprisingly, only 0.16% of CpG islands were differentially methylated and only a few DMRs were located on known gene promoters (n = 283) or enhancers (n = 190). Notably, the long-interspersed element (LINE), short-interspersed element (SINE), and long terminal repeat (LTR1) transposable elements showed reduced methylation (P < 0.05) in IVF livers. Cellular metabolic process, hepatic fibrosis, and insulin receptor signaling were some of the principal biological processes and CPs modified by IVF. In summary, IVF modifies the DNA methylation signature in the adult liver, resulting in hypomethylation of genes involved in metabolism and gene transcription regulation. These findings may shed light on the mechanisms underlying the developmental origin of health and disease.

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