scholarly journals Influence of tissue, age, and environmental quality on DNA methylation in Alligator mississippiensis

Reproduction ◽  
2014 ◽  
Vol 147 (4) ◽  
pp. 503-513 ◽  
Author(s):  
Benjamin B Parrott ◽  
John A Bowden ◽  
Satomi Kohno ◽  
Jessica A Cloy-McCoy ◽  
Matthew D Hale ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Whole Blood ◽  
Epigenetic Modification ◽  
Alligator Mississippiensis ◽  
Sentinel Species ◽  
Global Dna Methylation ◽  
American Alligator ◽  
Global Methylation ◽  
Contaminant Exposure ◽  
Liquid Chromatography Tandem Mass

Epigenetic modifications are key mediators of the interactions between the environment and an organism's genome. DNA methylation represents the best-studied epigenetic modification to date and is known to play key roles in regulating transcriptional activity and promoting chromosome stability. Our laboratory has previously demonstrated the utility of the American alligator (Alligator mississippiensis) as a sentinel species to investigate the persistent effects of environmental contaminant exposure on reproductive health. Here, we incorporate a liquid chromatography–tandem mass spectrometry method to directly measure the total (global) proportion of 5-methyl-2′-deoxycytidine (5mdC) in ovarian and whole blood DNA from alligators. Global DNA methylation in ovaries was significantly elevated in comparison with that of whole blood. However, DNA methylation appeared similar in juvenile alligators reared under controlled laboratory conditions but originating from three sites with dissimilar environmental qualities, indicating an absence of detectable site-of-origin effects on persistent levels of global 5mdC content. Analyses of tissues across individuals revealed a surprising lack of correlation between global methylation levels in blood and ovary. In addition, global DNA methylation in blood samples from juvenile alligators was elevated compared with those from adults, suggesting that age, as observed in mammals, may negatively influence global DNA methylation levels in alligators. To our knowledge, this is the first study examining global levels of DNA methylation in the American alligator and provides a reference point for future studies examining the interplay of epigenetics and environmental factors in a long-lived sentinel species.

scholarly journals Global Methylation and Hydroxymethylation in DNA from Blood and Saliva in Healthy Volunteers

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Lode Godderis ◽  
Caroline Schouteden ◽  
Ali Tabish ◽  
Katrien Poels ◽  
Peter Hoet ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Global Dna Methylation ◽  
Global Methylation ◽  
Blood Samples ◽  
Dna Hydroxymethylation ◽  
Alu Elements ◽  
Human Dna ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Pyrosequencing Technology

Aims. We describe a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify and compare simultaneously global methylation and hydroxymethylation in human DNA of different tissues.Materials and Methods. Blood and saliva DNA from fourteen volunteers was processed for epigenetic endpoints using LC-MS/MS and PCR-pyrosequencing technology.Results. Global DNA methylation was significantly lower in saliva (mean 4.61% ±  0.80%), compared to blood samples (5.70% ± 0.22%). In contrast, saliva (0.036% ± 0.011%) revealed significantly higher hydroxymethylation compared to blood samples (mean 0.027% ± 0.004%). Whereas we did not find significant correlations for both epigenetic measures between the tissues, a significant association was observed between global methylation and global hydroxymethylation in saliva DNA. Neither LINE-1 nor Alu elements of blood and saliva correlated, nor were they correlated with the DNA hydroxymethylation of blood or saliva, respectively.Conclusion. Global DNA methylation and hydroxymethylation of cytosine can be quantified simultaneously by LC-MS/MS. Saliva DNA cannot be considered as a surrogate for blood DNA to study epigenetic endpoints.

scholarly journals Global DNA methylation loss associated with mercury contamination and aging in the American alligator (Alligator mississippiensis)

2016 ◽  
Vol 545-546 ◽  
pp. 389-397 ◽  
Author(s):  
Frances M. Nilsen ◽  
Benjamin B. Parrott ◽  
John A. Bowden ◽  
Brittany L. Kassim ◽  
Stephen E. Somerville ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Mercury Contamination ◽  
Alligator Mississippiensis ◽  
Global Dna Methylation ◽  
American Alligator

Examination of the dynamics of global DNA methylation pattern establishment during spermatogenesiss

2007 ◽  
Vol 30 (4) ◽  
pp. 90
Author(s):  
Kirsten Niles ◽  
Sophie La Salle ◽  
Christopher Oakes ◽  
Jacquetta Trasler
Keyword(s):  
Dna Methylation ◽  
Germ Cell ◽  
Germ Cells ◽  
Epigenetic Modification ◽  
Methylation Pattern ◽  
Chromosome 9 ◽  
Specific Gene ◽  
Global Methylation ◽  
Dna Methylation Pattern ◽  
Methylation Patterns

Background: DNA methylation is an epigenetic modification involved in gene expression, genome stability, and genomic imprinting. In the male, methylation patterns are initially erased in primordial germ cells (PGCs) as they enter the gonadal ridge; methylation patterns are then acquired on CpG dinucleotides during gametogenesis. Correct pattern establishment is essential for normal spermatogenesis. To date, the characterization and timing of methylation pattern acquisition in PGCs has been described using a limited number of specific gene loci. This study aimed to describe DNA methylation pattern establishment dynamics during male gametogenesis through global methylation profiling techniques in a mouse model. Methods: Using a chromosome based approach, primers were designed for 24 regions spanning chromosome 9; intergenic, non-repeat, non-CpG island sequences were chosen for study based on previous evidence that these types of sequences are targets for testis-specific methylation events. The percent methylation was determined in each region by quantitative analysis of DNA methylation using real-time PCR (qAMP). The germ cell-specific pattern was determined by comparing methylation between spermatozoa and liver. To examine methylation in developing germ cells, spermatogonia from 2 day- and 6 day-old Oct4-GFP (green fluorescent protein) mice were isolated using fluorescence activated cell sorting. Results: As compared to liver, four loci were hypomethylated and five loci were hypermethylated in spermatozoa, supporting previous results indicating a unique methylation pattern in male germ cells. Only one region was hypomethylated and no regions were hypermethylated in day 6 spermatogonia as compared to mature spermatozoa, signifying that the bulk of DNA methylation is established prior to type A spermatogonia. The methylation in day 2 spermatogonia, germ cells that are just commencing mitosis, revealed differences of 15-20% compared to day 6 spermatogonia at five regions indicating that the most crucial phase of DNA methylation acquisition occurs prenatally. Conclusion: Together, these studies provide further evidence that germ cell methylation patterns differ from those in somatic tissues and suggest that much of methylation at intergenic sites is acquired during prenatal germ cell development. (Supported by CIHR)

scholarly journals Epigenome-wide association study of whole blood gene expression in Framingham Heart Study participants provides molecular insight into the potential role of CHRNA5 in cigarette smoking-related lung diseases

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Chen Yao ◽  
Roby Joehanes ◽  
Rory Wilson ◽  
Toshiko Tanaka ◽  
Luigi Ferrucci ◽  
...  
Keyword(s):  
Gene Expression ◽  
Lung Cancer ◽  
Dna Methylation ◽  
Cigarette Smoking ◽  
Association Study ◽  
Whole Blood ◽  
Lung Diseases ◽  
Epigenetic Modification ◽  
Blood Gene Expression ◽  
Increased Risk

Abstract Background DNA methylation is a key epigenetic modification that can directly affect gene regulation. DNA methylation is highly influenced by environmental factors such as cigarette smoking, which is causally related to chronic obstructive pulmonary disease (COPD) and lung cancer. To date, there have been few large-scale, combined analyses of DNA methylation and gene expression and their interrelations with lung diseases. Results We performed an epigenome-wide association study of whole blood gene expression in ~ 6000 individuals from four cohorts. We discovered and replicated numerous CpGs associated with the expression of cis genes within 500 kb of each CpG, with 148 to 1,741 cis CpG-transcript pairs identified across cohorts. We found that the closer a CpG resided to a transcription start site, the larger its effect size, and that 36% of cis CpG-transcript pairs share the same causal genetic variant. Mendelian randomization analyses revealed that hypomethylation and lower expression of CHRNA5, which encodes a smoking-related nicotinic receptor, are causally linked to increased risk of COPD and lung cancer. This putatively causal relationship was further validated in lung tissue data. Conclusions Our results provide a large and comprehensive association study of whole blood DNA methylation with gene expression. Expression platform differences rather than population differences are critical to the replication of cis CpG-transcript pairs. The low reproducibility of trans CpG-transcript pairs suggests that DNA methylation regulates nearby rather than remote gene expression. The putatively causal roles of methylation and expression of CHRNA5 in relation to COPD and lung cancer provide evidence for a mechanistic link between patterns of smoking-related epigenetic variation and lung diseases, and highlight potential therapeutic targets for lung diseases and smoking cessation.

scholarly journals Oxidative damage, inflammation, genotoxic effect, and global DNA methylation caused by inhalation of formaldehyde and the purpose of melatonin

2020 ◽  
Vol 9 (6) ◽  
pp. 778-789
Author(s):  
Letícia Bernardini ◽  
Eduardo Barbosa ◽  
Mariele Feiffer Charão ◽  
Gabriela Goethel ◽  
Diana Muller ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Bone Marrow ◽  
Oxidative Damage ◽  
Bronchoalveolar Lavage ◽  
Bone Marrow Cells ◽  
Histological Study ◽  
Global Dna Methylation ◽  
Protective Effects ◽  
Global Methylation ◽  
Protein Thiols

Abstract Formaldehyde (FA) exposure has been proven to increase the risk of asthma and cancer. This study aimed to evaluate for 28 days the FA inhalation effects on oxidative stress, inflammation process, genotoxicity, and global DNA methylation in mice as well as to investigate the potential protective effects of melatonin. For that, analyses were performed on lung, liver and kidney tissues, blood, and bone marrow. Bronchoalveolar lavage was used to measure inflammatory parameters. Lipid peroxidation (TBARS), protein carbonyl (PCO), non-protein thiols (NPSH), catalase activity (CAT), comet assay, micronuclei (MN), and global methylation were determined. The exposure to 5-ppm FA resulted in oxidative damage to the lung, presenting a significant increase in TBARS and NO levels and a decrease in NPSH levels, besides an increase in inflammatory cells recruited for bronchoalveolar lavage. Likewise, in the liver tissue, the exposure to 5-ppm FA increased TBARS and PCO levels and decreased NPSH levels. In addition, FA significantly induced DNA damage, evidenced by the increase of % tail moment and MN frequency. The pretreatment of mice exposed to FA applying melatonin improved inflammatory and oxidative damage in lung and liver tissues and attenuated MN formation in bone marrow cells. The pulmonary histological study reinforced the results observed in biochemical parameters, demonstrating the potential beneficial role of melatonin. Therefore, our results demonstrated that FA exposure with repeated doses might induce oxidative damage, inflammatory, and genotoxic effects, and melatonin minimized the toxic effects caused by FA inhalation in mice.

scholarly journals DNA Methylation in T-Cell Acute Lymphoblastic Leukemia: In Search for Clinical and Biological Meaning

2021 ◽  
Vol 22 (3) ◽  
pp. 1388
Author(s):  
Natalia Maćkowska ◽  
Monika Drobna-Śledzińska ◽  
Michał Witt ◽  
Małgorzata Dawidowska
Keyword(s):  
Dna Methylation ◽  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Epigenetic Modification ◽  
Lymphoblastic Leukemia ◽  
Leukemic Cells ◽  
Global Methylation ◽  
Current State ◽  
History Of ◽  
Cell Acute Lymphoblastic Leukemia

Distinct DNA methylation signatures, related to different prognosis, have been observed across many cancers, including T-cell acute lymphoblastic leukemia (T-ALL), an aggressive hematological neoplasm. By global methylation analysis, two major phenotypes might be observed in T-ALL: hypermethylation related to better outcome and hypomethylation, which is a candidate marker of poor prognosis. Moreover, DNA methylation holds more than a clinical meaning. It reflects the replicative history of leukemic cells and most likely different mechanisms underlying leukemia development in these T-ALL subtypes. The elucidation of the mechanisms and aberrations specific to (epi-)genomic subtypes might pave the way towards predictive diagnostics and precision medicine in T-ALL. We present the current state of knowledge on the role of DNA methylation in T-ALL. We describe the involvement of DNA methylation in normal hematopoiesis and T-cell development, focusing on epigenetic aberrations contributing to this leukemia. We further review the research investigating distinct methylation phenotypes in T-ALL, related to different outcomes, pointing to the most recent research aimed to unravel the biological mechanisms behind differential methylation. We highlight how technological advancements facilitated broadening the perspective of the investigation into DNA methylation and how this has changed our understanding of the roles of this epigenetic modification in T-ALL.

scholarly journals A maternal effect regulates global DNA methylation patterns

2020 ◽  
Author(s):  
Remco Loos ◽  
Valeria Carola ◽  
Enrica Audero ◽  
Elena Brini ◽  
Luisa Lo Iacono ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Maternal Effect ◽  
Cpg Island ◽  
Inbred Mouse ◽  
Mouse Strains ◽  
Global Dna Methylation ◽  
Global Methylation ◽  
Genome Methylation ◽  
Genetic And Environmental Factors ◽  
Methylation Patterns

AbstractVariation in DNA methylation between individuals has been shown to be influenced by both genetic and environmental factors. However, the relative impact of genetic and non-genetic factors on DNA methylation patterns across the mammalian genome has not been systematically studied. We performed whole-genome methylation analysis in two inbred mouse strains, revealing striking differences in the global distribution of DNA methylation. Although global methylation patterns were indistinguishable for most genomic features, a significant increase in the number of unmethylated CpG-island promoters and first exons was observed between strains. Experiments using F1 reciprocal hybrid strains demonstrated that the genotype of the mother dictated global DNA methylation patterns. Cross-fostering experiments ruled out a postnatal maternal effect on these differences and suggested that they were driven by a prenatal maternal effect, possibly via differential deposition of maternal gene products into the oocyte or uterine environment. These data demonstrate that maternal effects have a major impact on global DNA methylation patterns.

scholarly journals The Long-Term Impact of Mild Traumatic Brain Injuries on Multiple Functional Outcomes and Epigenetics: A Pilot Study with College Students

2020 ◽  
Author(s):  
Hyunhwa Lee ◽  
Sungchul Lee ◽  
Ipuna Black ◽  
Laura Salado ◽  
Jonica Estrada ◽  
...  
Keyword(s):  
College Students ◽  
Dna Methylation ◽  
Pilot Study ◽  
Visual Function ◽  
Postural Balance ◽  
Sleep Disturbances ◽  
Global Dna Methylation ◽  
Balance Performance ◽  
Global Methylation

People who suffer a mild traumatic brain injury (mTBI) have heterogeneous symptoms and disease trajectories, which make it difficult to precisely diagnose and assess complications long-term. Insufficient information is available regarding how to precisely diagnose and assess mTBI. This study identified and compared deficits in cognitive, psychosocial, visual functions, and balance performance between college students with and without histories of mTBI. Global DNA methylation ratio (5-mC%) in blood was also compared as a peripheral epigenetic marker. Twenty-five volunteers participated in this pilot study, including 11 mTBI cases (27.3% females; mean age of 28.7 years, SD=5.92) and 14 healthy controls (64.3% females; mean age of 22.0, SD=4.13). All the participants were assessed for cognitive (by NIH toolbox—executive function, memory, and processing speed), psychological (by PROMIS—depression, anxiety, and sleep disturbances), visual function (by King-Devick and binocular accommodative tests), postural balance performance (by a force plate), and blood 5-mC% (global methylation) levels. Students with mTBI reported significantly poorer episodic memory, severe anxiety, and more sleep disturbance problems. They also had higher blood 5-mC% level (all p’s<.05). No significant differences were found in visual function and postural balance. These findings validate changes in cognitive, psychosocial, and global DNA methylation long after mTBI.

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