Epigenetic Effect of Environmental Factors on Autism Spectrum Disorders

Directory of Open Access Journals (Sweden)

Takeo Kubota

2016-05-01

Full Text Available Both environmental factors and genetic factors are involved in the pathogenesis of autism spectrum disorders (ASDs. Epigenetics, an essential mechanism for gene regulation based on chemical modifications of DNA and histone proteins, is also involved in congenital ASDs. It was recently demonstrated that environmental factors, such as endocrine disrupting chemicals and mental stress in early life, can change epigenetic status and gene expression, and can cause ASDs. Moreover, environmentally induced epigenetic changes are not erased during gametogenesis and are transmitted to subsequent generations, leading to changes in behavior phenotypes. However, epigenetics has a reversible nature since it is based on the addition or removal of chemical residues, and thus the original epigenetic status may be restored. Indeed, several antidepressants and anticonvulsants used for mental disorders including ASDs restore the epigenetic state and gene expression. Therefore, further epigenetic understanding of ASDs is important for the development of new drugs that take advantages of epigenetic reversibility.

Epigenetic Effect of Environmental Factors on Autism Spectrum Disorders.

Science.gov (United States)

Kubota, Takeo; Mochizuki, Kazuki

2016-05-14

Both environmental factors and genetic factors are involved in the pathogenesis of autism spectrum disorders (ASDs). Epigenetics, an essential mechanism for gene regulation based on chemical modifications of DNA and histone proteins, is also involved in congenital ASDs. It was recently demonstrated that environmental factors, such as endocrine disrupting chemicals and mental stress in early life, can change epigenetic status and gene expression, and can cause ASDs. Moreover, environmentally induced epigenetic changes are not erased during gametogenesis and are transmitted to subsequent generations, leading to changes in behavior phenotypes. However, epigenetics has a reversible nature since it is based on the addition or removal of chemical residues, and thus the original epigenetic status may be restored. Indeed, several antidepressants and anticonvulsants used for mental disorders including ASDs restore the epigenetic state and gene expression. Therefore, further epigenetic understanding of ASDs is important for the development of new drugs that take advantages of epigenetic reversibility.

Genome mapping and characterization of the Anopheles gambiae heterochromatin

Directory of Open Access Journals (Sweden)

Sharakhova Maria V

2010-08-01

Full Text Available Abstract Background Heterochromatin plays an important role in chromosome function and gene regulation. Despite the availability of polytene chromosomes and genome sequence, the heterochromatin of the major malaria vector Anopheles gambiae has not been mapped and characterized. Results To determine the extent of heterochromatin within the An. gambiae genome, genes were physically mapped to the euchromatin-heterochromatin transition zone of polytene chromosomes. The study found that a minimum of 232 genes reside in 16.6 Mb of mapped heterochromatin. Gene ontology analysis revealed that heterochromatin is enriched in genes with DNA-binding and regulatory activities. Immunostaining of the An. gambiae chromosomes with antibodies against Drosophila melanogaster heterochromatin protein 1 (HP1 and the nuclear envelope protein lamin Dm0 identified the major invariable sites of the proteins' localization in all regions of pericentric heterochromatin, diffuse intercalary heterochromatin, and euchromatic region 9C of the 2R arm, but not in the compact intercalary heterochromatin. To better understand the molecular differences among chromatin types, novel Bayesian statistical models were developed to analyze genome features. The study found that heterochromatin and euchromatin differ in gene density and the coverage of retroelements and segmental duplications. The pericentric heterochromatin had the highest coverage of retroelements and tandem repeats, while intercalary heterochromatin was enriched with segmental duplications. We also provide evidence that the diffuse intercalary heterochromatin has a higher coverage of DNA transposable elements, minisatellites, and satellites than does the compact intercalary heterochromatin. The investigation of 42-Mb assembly of unmapped genomic scaffolds showed that it has molecular characteristics similar to cytologically mapped heterochromatin. Conclusions Our results demonstrate that Anopheles polytene chromosomes

The Role of piRNA-Mediated Epigenetic Silencing in the Population Dynamics of Transposable Elements in Drosophila melanogaster.

Directory of Open Access Journals (Sweden)

Yuh Chwen G Lee

2015-06-01

Full Text Available The piwi-interacting RNAs (piRNA are small RNAs that target selfish transposable elements (TEs in many animal genomes. Until now, piRNAs' role in TE population dynamics has only been discussed in the context of their suppression of TE transposition, which alone is not sufficient to account for the skewed frequency spectrum and stable containment of TEs. On the other hand, euchromatic TEs can be epigenetically silenced via piRNA-dependent heterochromatin formation and, similar to the widely known "Position-effect variegation", heterochromatin induced by TEs can "spread" into nearby genes. We hypothesized that the piRNA-mediated spread of heterochromatin from TEs into adjacent genes has deleterious functional effects and leads to selection against individual TEs. Unlike previously identified deleterious effects of TEs due to the physical disruption of DNA, the functional effect we investigated here is mediated through the epigenetic influences of TEs. We found that the repressive chromatin mark, H3K9me, is elevated in sequences adjacent to euchromatic TEs at multiple developmental stages in Drosophila melanogaster. Furthermore, the heterochromatic states of genes depend not only on the number of and distance from adjacent TEs, but also on the likelihood that their nearest TEs are targeted by piRNAs. These variations in chromatin status probably have functional consequences, causing genes near TEs to have lower expression. Importantly, we found stronger selection against TEs that lead to higher H3K9me enrichment of adjacent genes, demonstrating the pervasive evolutionary consequences of TE-induced epigenetic silencing. Because of the intrinsic biological mechanism of piRNA amplification, spread of TE heterochromatin could result in the theoretically required synergistic deleterious effects of TE insertions for stable containment of TE copy number. The indirect deleterious impact of piRNA-mediated epigenetic silencing of TEs is a previously

Karyotypes and heterochromatin variation (C-bands in Melipona species (Hymenoptera, Apidae, Meliponinae

Directory of Open Access Journals (Sweden)

Rocha Marla Piumbini

1998-01-01

Full Text Available We describe the karyotypes of eight bee species of the genus Melipona and compare them in terms of heterochromatin content and location (C-banding technique. All species had 2n = 18 (females and n = 9 (males chromosomes, but a wide variation in heterochromatin content was detected among karyotypes. On the basis of these differences, the species were divided into two functional groups, one of them comprising species with a karyotype having a low heterochromatin content (M. bicolor bicolor, M. quadrifasciata, M. marginata, and M. asilvai, and the other species with a high heterochromatin content (M. seminigra fuscopilosa, M. capixaba, M. scutellaris, and M. captiosa. In the species with high heterochromatin content, heterochromatin occupied practically the entire extent of all chromosomes, with euchromatin being limited to the extremities, a fact that prevented observation of the centromere. In contrast, in the species with karyotypes having a low heterochromatin content, heterochromatin was visualized only in some chromosomes. In the chromosomes in which it was present, heterochromatin was located in the centromere or on the short arm. M. bicolor bicolor had the smallest heterochromatin content with only three chromosome pairs presenting heterochromatin in females. Increased heterochromatin content may be explained by interstitial and pericentromeric growth.

A general approach for controlling transcription and probing epigenetic mechanisms: application to the CD4 locus.

Science.gov (United States)

Wan, Mimi; Kaundal, Ravinder; Huang, Haichang; Zhao, Jiugang; Yang, Xiaojun; Chaiyachati, Barbara H; Li, Sicong; Chi, Tian

2013-01-15

Synthetic regulatory proteins such as tetracycline (tet)-controlled transcription factors are potentially useful for repression as well as ectopic activation of endogenous genes and also for probing their regulatory mechanisms, which would offer a versatile genetic tool advantageous over conventional gene targeting methods. In this study, we provide evidence supporting this concept using Cd4 as a model. CD4 is expressed in double-positive and CD4 cells but irreversibly silenced in CD8 cells. The silencing is mediated by heterochromatin established during CD8 lineage development via transient action of the Cd4 silencer; once established, the heterochromatin becomes self-perpetuating independently of the Cd4 silencer. Using a tet-sensitive Cd4 allele harboring a removable Cd4 silencer, we found that a tet-controlled repressor recapitulated the phenotype of Cd4-deficient mice, inhibited Cd4 expression in a reversible and dose-dependent manner, and could surprisingly replace the Cd4 silencer to induce irreversible Cd4 silencing in CD8 cells, thus suggesting the Cd4 silencer is not the (only) determinant of heterochromatin formation. In contrast, a tet-controlled activator reversibly disrupted Cd4 silencing in CD8 cells. The Cd4 silencer impeded this disruption but was not essential for its reversal, which revealed a continuous role of the silencer in mature CD8 cells while exposing a remarkable intrinsic self-regenerative ability of heterochromatin after forced disruption. These data demonstrate an effective approach for gene manipulation and provide insights into the epigenetic Cd4 regulatory mechanisms that are otherwise difficult to obtain.

An emerging role for epigenetic factors in relation to executive function.

Science.gov (United States)

Ibrahim, Omar; Sutherland, Heidi G; Haupt, Larisa M; Griffiths, Lyn R

2017-11-20

Executive function (EF) includes a range of decision-making and higher-order thinking processes. Although the genetic basis of EF has been studied and reviewed, epigenetic factors that influence EF are an emerging field of interest; here, we summarize the current research. Work relating to different word combinations of 'Executive Function' and 'Epigenetic' was identified through three academic search directories. Inclusion criteria were human populations, EF testing, epigenetic testing or genotyping related to epigenetic regulation. To date, 14 studies have been reported, which examined epigenetic variation, in particular DNA methylation, in relation to EF assessments conducted in human subjects, with some positive associations found. Study populations included healthy cohorts, as well as psychiatric and neurological patient cohorts. Epigenetics in relation to EF is an emerging area of investigation with relatively few studies to date. Most assay DNA methylation, with some studies suggesting that epigenetic factors can be associated with EF. EF constitutes complex phenotypic and genotypic correlates that differ because of cohort attributes as well as the targeted task examined. Larger studies are required to further elucidate the contribution of epigenetic factors to EF with the identification of epigenetic modifications influencing EF having potential to provide new biomarkers for neuropsychiatric disorders. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com

The inactive X chromosome is epigenetically unstable and transcriptionally labile in breast cancer.

Science.gov (United States)

Chaligné, Ronan; Popova, Tatiana; Mendoza-Parra, Marco-Antonio; Saleem, Mohamed-Ashick M; Gentien, David; Ban, Kristen; Piolot, Tristan; Leroy, Olivier; Mariani, Odette; Gronemeyer, Hinrich; Vincent-Salomon, Anne; Stern, Marc-Henri; Heard, Edith

2015-04-01

Disappearance of the Barr body is considered a hallmark of cancer, although whether this corresponds to genetic loss or to epigenetic instability and transcriptional reactivation is unclear. Here we show that breast tumors and cell lines frequently display major epigenetic instability of the inactive X chromosome, with highly abnormal 3D nuclear organization and global perturbations of heterochromatin, including gain of euchromatic marks and aberrant distributions of repressive marks such as H3K27me3 and promoter DNA methylation. Genome-wide profiling of chromatin and transcription reveal modified epigenomic landscapes in cancer cells and a significant degree of aberrant gene activity from the inactive X chromosome, including several genes involved in cancer promotion. We demonstrate that many of these genes are aberrantly reactivated in primary breast tumors, and we further demonstrate that epigenetic instability of the inactive X can lead to perturbed dosage of X-linked factors. Taken together, our study provides the first integrated analysis of the inactive X chromosome in the context of breast cancer and establishes that epigenetic erosion of the inactive X can lead to the disappearance of the Barr body in breast cancer cells. This work offers new insights and opens up the possibility of exploiting the inactive X chromosome as an epigenetic biomarker at the molecular and cytological levels in cancer. © 2015 Chaligné et al.; Published by Cold Spring Harbor Laboratory Press.

Overexpression of the heterochromatinization factor BAHD1 in HEK293 cells differentially reshapes the DNA methylome on autosomes and X chromosome.

Directory of Open Access Journals (Sweden)

Emanuele eLibertini

2015-12-01

Full Text Available BAH domain-containing protein 1 (BAHD1 is involved in heterochromatin formation and gene repression in human cells. BAHD1 also localizes to the inactive X chromosome (Xi, but the functional significance of this targeting is unknown. So far, research on this protein has been hampered by its low endogenous abundance and its role in epigenetic regulation remains poorly explored. In this work, we used whole-genome bisulfite sequencing (BS-seq to compare the DNA methylation profile of HEK293 cells expressing low levels of BAHD1 (HEK-CT to that of isogenic cells stably overexpressing BAHD1 (HEK-BAHD1. We show that increasing BAHD1 levels induces de novo DNA methylation on autosomes and a marked hypomethylation on the X chromosome (chrX. We identified 91,358 regions that have different methylation patterns in HEK-BAHD1 compared to HEK-CT cells (termed BAHD1-DMRs, of which 83,850 mapped on autosomes and 7,508 on the X chromosome (chrX. Autosomal BAHD1-DMRs were predominantly hypermethylated and located to satellites, interspersed repeats and intergenic regions. In contrast, BAHD1-DMRs on chrX were mainly hypomethylated and located to gene bodies and enhancers. We further found that BAHD1-DMRs display a higher-order organization by being clustered within large chromosomal domains. Half of these BAHD1-Associated differentially methylated Domains (BADs overlapped with lamina-associated domains (LADs. Based on these results, we propose that BAHD1-mediated heterochromatin formation is linked to DNA methylation and may play a role in the spatial architecture of the genome.

Ring-like distribution of constitutive heterochromatin in bovine senescent cells.

Science.gov (United States)

Pichugin, Andrey; Beaujean, Nathalie; Vignon, Xavier; Vassetzky, Yegor

2011-01-01

Cells that reach "Hayflick limit" of proliferation, known as senescent cells, possess a particular type of nuclear architecture. Human senescent cells are characterized by the presence of highly condensed senescent associated heterochromatin foci (SAHF) that can be detected both by immunostaining for histone H3 three-methylated at lysine 9 (H3K9me3) and by DAPI counterstaining. We have studied nuclear architecture in bovine senescent cells using a combination of immunofluorescence and 3D fluorescent in-situ hybridization (FISH). Analysis of heterochromatin distribution in bovine senescent cells using fluorescent in situ hybridization for pericentric chromosomal regions, immunostaining of H3K9me3, centromeric proteins CENP A/B and DNA methylation showed a lower level of heterochromatin condensation as compared to young cells. No SAHF foci were observed. Instead, we observed fibrous ring-like or ribbon-like heterochromatin patterns that were undetectable with DAPI counterstaining. These heterochromatin fibers were associated with nucleoli. Constitutive heterochromatin in bovine senescent cells is organized in ring-like structures.

Ring-like distribution of constitutive heterochromatin in bovine senescent cells.

Directory of Open Access Journals (Sweden)

Andrey Pichugin

Full Text Available BACKGROUND: Cells that reach "Hayflick limit" of proliferation, known as senescent cells, possess a particular type of nuclear architecture. Human senescent cells are characterized by the presence of highly condensed senescent associated heterochromatin foci (SAHF that can be detected both by immunostaining for histone H3 three-methylated at lysine 9 (H3K9me3 and by DAPI counterstaining. METHODS: We have studied nuclear architecture in bovine senescent cells using a combination of immunofluorescence and 3D fluorescent in-situ hybridization (FISH. RESULTS: Analysis of heterochromatin distribution in bovine senescent cells using fluorescent in situ hybridization for pericentric chromosomal regions, immunostaining of H3K9me3, centromeric proteins CENP A/B and DNA methylation showed a lower level of heterochromatin condensation as compared to young cells. No SAHF foci were observed. Instead, we observed fibrous ring-like or ribbon-like heterochromatin patterns that were undetectable with DAPI counterstaining. These heterochromatin fibers were associated with nucleoli. CONCLUSIONS: Constitutive heterochromatin in bovine senescent cells is organized in ring-like structures.

Epigenetic susceptibility factors for prostate cancer with aging.

Science.gov (United States)

Damaschke, N A; Yang, B; Bhusari, S; Svaren, J P; Jarrard, D F

2013-12-01

Increasing age is a significant risk factor for prostate cancer. The prostate is exposed to environmental and endogenous stress that may underlie this remarkable incidence. DNA methylation, genomic imprinting, and histone modifications are examples of epigenetic factors known to undergo change in the aging and cancerous prostate. In this review we examine the data linking epigenetic alterations in the prostate with aging to cancer development. An online search of current and past peer reviewed literature on epigenetic changes with cancer and aging was performed. Relevant articles were analyzed. Epigenetic changes are responsible for modifying expression of oncogenes and tumor suppressors. Several of these changes may represent a field defect that predisposes to cancer development. Focal hypermethylation occurs at CpG islands in the promoters of certain genes including GSTP1, RARβ2, and RASSF1A with both age and cancer, while global hypomethylation is seen in prostate cancer and known to occur in the colon and other organs. A loss of genomic imprinting is responsible for biallelic expression of the well-known Insulin-like Growth Factor 2 (IGF2) gene. Loss of imprinting (LOI) at IGF2 has been documented in cancer and is also known to occur in benign aging prostate tissue marking the presence of cancer. Histone modifications have the ability to dictate chromatin structure and direct gene expression. Epigenetic changes with aging represent molecular mechanisms to explain the increased susceptibly of the prostate to develop cancer in older men. These changes may provide an opportunity for diagnostic and chemopreventive strategies given the epigenome can be modified. © 2013 Wiley Periodicals, Inc.

Role of Heterochromatin Epigenetic Factors in CML

Science.gov (United States)

2008-08-01

ORGANIZATION : Pennsylvania State University Hershey, PA 17033 REPORT DATE: August 2008...7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Pennsylvania State University Hershey, PA...VGLL4 Homo sapiens vestigial like 4 (Drosophila) (VGLL4), mRNA. 1.05 0.50 0.71 NM_033644.2 FBXW11 Homo sapiens F-box and WD-40 domain protein 11

Mammalian ChlR1 has a role in heterochromatin organization

International Nuclear Information System (INIS)

Inoue, Akira; Hyle, Judith; Lechner, Mark S.; Lahti, Jill M.

2011-01-01

The ChlR1 DNA helicase, encoded by DDX11 gene, which is responsible for Warsaw breakage syndrome (WABS), has a role in sister-chromatid cohesion. In this study, we show that human ChlR1 deficient cells exhibit abnormal heterochromatin organization. While constitutive heterochromatin is discretely localized at perinuclear and perinucleolar regions in control HeLa cells, ChlR1-depleted cells showed dispersed localization of constitutive heterochromatin accompanied by disrupted centromere clustering. Cells isolated from Ddx11 -/- embryos also exhibited diffuse localization of centromeres and heterochromatin foci. Similar abnormalities were found in HeLa cells depleted of combinations of HP1α and HP1β. Immunofluorescence and chromatin immunoprecipitation showed a decreased level of HP1α at pericentric regions in ChlR1-depleted cells. Trimethyl-histone H3 at lysine 9 (H3K9-me3) was also modestly decreased at pericentric sequences. The abnormality in pericentric heterochromatin was further supported by decreased DNA methylation within major satellite repeats of Ddx11 -/- embryos. Furthermore, micrococcal nuclease (MNase) assay revealed a decreased chromatin density at the telomeres. These data suggest that in addition to a role in sister-chromatid cohesion, ChlR1 is also involved in the proper formation of heterochromatin, which in turn contributes to global nuclear organization and pleiotropic effects. -- Highlights: → New role for ChlR1 (DDX11), a cohesinopathy gene, in heterochromatin organization. → Loss of ChlR1 altered heterochromatin localization and centromere clustering. → Reduced ChlR1 levels also reduced HP1α and H3K9-me3 binding to pericentric DNA. → Decreased DNA methylation was found in pericentric repeats of Ddx11 -/- embryos. → These findings will aid in understanding the pathogenesis of Warsaw breakage syndrome.

DNA Methylation: An Epigenetic Risk Factor in Preterm Birth

Science.gov (United States)

Menon, Ramkumar; Conneely, Karen N.; Smith, Alicia K.

2012-01-01

Spontaneous preterm birth (PTB; birth prior to 37 weeks of gestation) is a complex phenotype with multiple risk factors that complicate our understanding of its etiology. A number of recent studies have supported the hypothesis that epigenetic modifications such as DNA methylation induced by pregnancy-related risk factors may influence the risk of PTB or result in changes that predispose a neonate to adult-onset diseases. The critical role of timing of gene expression in the etiology of PTB makes it a highly relevant disorder in which to examine the potential role of epigenetic changes. Because changes in DNA methylation patterns can result in long-term consequences, it is of critical interest to identify the epigenetic patterns associated with adverse pregnancy outcomes. This review examines the potential role of DNA methylation as a risk factor for PTB and discusses several issues and limitations that should be considered when planning DNA methylation studies. PMID:22228737

Pairing of heterochromatin in response to cellular stress

International Nuclear Information System (INIS)

Abdel-Halim, H.I.; Mullenders, L.H.F.; Boei, J.J.W.A.

2006-01-01

We previously reported that exposure of human cells to DNA-damaging agents (X-rays and mitomycin C (MMC)) induces pairing of the homologous paracentromeric heterochromatin of chromosome 9 (9q12-13). Here, we show that UV irradiation and also heat shock treatment of human cells lead to similar effects. Since the various agents induce very different types and frequencies of damage to cellular constituents, the data suggest a general stress response as the underlying mechanism. Moreover, local UV irradiation experiments revealed that pairing of heterochromatin is an event that can be triggered without induction of DNA damage in the heterochromatic sequences. The repair deficient xeroderma pigmentosum cells (group F) previously shown to fail pairing after MMC displayed elevated pairing after heat shock treatment but not after UV exposure. Taken together, the present results indicate that pairing of heterochromatin following exposure to DNA-damaging agents is initiated by a general stress response and that the sensing of stress or the maintenance of the paired status of the heterochromatin might be dependent on DNA repair

The Epigenetic Cytocrin Pathway to the Nucleus. Epigenetic Factors, Epigenetic Mediators, and Epigenetic Traits. A Biochemist Perspective

Directory of Open Access Journals (Sweden)

Gemma Navarro

2017-11-01

Full Text Available A single word, Epigenetics, underlies one exciting subject in today's Science, with different sides and with interactions with philosophy. The apparent trivial description includes everything in between genotype and phenotype that occurs for a given unique DNA sequence/genome. This Perspective article first presents an historical overview and the reasons for the lack of consensus in the field, which derives from different interpretations of the diverse operative definitions of Epigenetics. In an attempt to reconcile the different views, we propose a novel concept, the “cytocrin system.” Secondly, the article questions the inheritability requirement and makes emphasis in the epigenetic mechanisms, known or to be discovered, that provide hope for combating human diseases. Hopes in cancer are at present in deep need of deciphering mechanisms to support ad hoc therapeutic approaches. Better perspectives are for diseases of the central nervous system, in particular to combat neurodegeneration and/or cognitive deficits in Alzheimer's disease. Neurons are post-mitotic cells and, therefore, epigenetic targets to prevent neurodegeneration should operate in non-dividing diseased cells. Accordingly, epigenetic-based human therapy may not need to count much on transmissible potential.

Epigenetic Risk Factors in PTSD and Depression

Directory of Open Access Journals (Sweden)

Florian Joachim Raabe

2013-08-01

Full Text Available Epidemiological and clinical studies have shown that children exposed to adverse experiences are at increased risk for the development of depression, anxiety disorders and PTSD. A history of child abuse and maltreatment increases the likelihood of being subsequently exposed to traumatic events or of developing PTSD as an adult. The brain is highly plastic during early life and encodes acquired information into lasting memories that normally subserve adaptation. Translational studies in rodents showed that enduring sensitization of neuronal and neuroendocrine circuits in response to early life adversity are likely risk factors of life time vulnerability to stress. Hereby, the hypothalamic-pituitary-adrenal (HPA axis integrates cognitive, behavioural and emotional responses to early-life stress and can be epigenetically programmed during sensitive windows of development. Epigenetic mechanisms, comprising reciprocal regulation of chromatin structure and DNA methylation, are important to establish and maintain sustained, yet potentially reversible, changes in gene transcription. The relevance of these findings for the development of PTSD requires further studies in humans where experience-dependent epigenetic programming can additionally depend on genetic variation in the underlying substrates which may protect from or advance disease development. Overall, identification of early-life stress associated epigenetic risk markers informing on previous stress history can help to advance early diagnosis, personalized prevention and timely therapeutic interventions, thus reducing long-term social and health costs.

PREditOR: a synthetic biology approach to removing heterochromatin from cells.

Science.gov (United States)

Molina, Oscar; Carmena, Mar; Maudlin, Isabella E; Earnshaw, William C

2016-12-01

It is widely accepted that heterochromatin is necessary to maintain genomic stability. However, direct experimental evidence supporting this is slim. Previous studies using either enzyme inhibitors, gene knockout or knockdown studies all are subject to the caveat that drugs may have off-target effects and enzymes that modify chromatin proteins to support heterochromatin formation may also have numerous other cellular targets as well. Here, we describe PREditOR (protein reading and editing of residues), a synthetic biology approach that allows us to directly remove heterochromatin from cells without either drugs or global interference with gene function. We find that removal of heterochromatin perturbs mitotic progression and causes a dramatic increase in chromosome segregation defects, possibly as a result of interfering with the normal centromeric localization of the chromosomal passenger complex.

DNA triplet repeats mediate heterochromatin-protein-1-sensitive variegated gene silencing.

Science.gov (United States)

Saveliev, Alexander; Everett, Christopher; Sharpe, Tammy; Webster, Zoë; Festenstein, Richard

2003-04-24

Gene repression is crucial to the maintenance of differentiated cell types in multicellular organisms, whereas aberrant silencing can lead to disease. The organization of DNA into chromatin and heterochromatin is implicated in gene silencing. In chromatin, DNA wraps around histones, creating nucleosomes. Further condensation of chromatin, associated with large blocks of repetitive DNA sequences, is known as heterochromatin. Position effect variegation (PEV) occurs when a gene is located abnormally close to heterochromatin, silencing the affected gene in a proportion of cells. Here we show that the relatively short triplet-repeat expansions found in myotonic dystrophy and Friedreich's ataxia confer variegation of expression on a linked transgene in mice. Silencing was correlated with a decrease in promoter accessibility and was enhanced by the classical PEV modifier heterochromatin protein 1 (HP1). Notably, triplet-repeat-associated variegation was not restricted to classical heterochromatic regions but occurred irrespective of chromosomal location. Because the phenomenon described here shares important features with PEV, the mechanisms underlying heterochromatin-mediated silencing might have a role in gene regulation at many sites throughout the mammalian genome and modulate the extent of gene silencing and hence severity in several triplet-repeat diseases.

The fission yeast heterochromatin protein Rik1 is required for telomere clustering during meiosis

DEFF Research Database (Denmark)

Tuzon, Creighton T; Borgstrøm, Britta; Weilguny, Dietmar

2004-01-01

Telomeres share the ability to silence nearby transcription with heterochromatin, but the requirement of heterochromatin proteins for most telomere functions is unknown. The fission yeast Rik1 protein is required for heterochromatin formation at centromeres and the mating-type locus, as it recrui...... meiosis. However, Rik1 is dispensable for the protective roles of telomeres in preventing chromosome end-fusion. Thus, a Swi6-independent heterochromatin function distinct from that at centromeres and the mating-type locus operates at telomeres during sexual differentiation....

Mapping the pericentric heterochromatin by comparative genomic hybridization analysis and chromosome deletions in Drosophila melanogaster.

Science.gov (United States)

He, Bing; Caudy, Amy; Parsons, Lance; Rosebrock, Adam; Pane, Attilio; Raj, Sandeep; Wieschaus, Eric

2012-12-01

Heterochromatin represents a significant portion of eukaryotic genomes and has essential structural and regulatory functions. Its molecular organization is largely unknown due to difficulties in sequencing through and assembling repetitive sequences enriched in the heterochromatin. Here we developed a novel strategy using chromosomal rearrangements and embryonic phenotypes to position unmapped Drosophila melanogaster heterochromatic sequence to specific chromosomal regions. By excluding sequences that can be mapped to the assembled euchromatic arms, we identified sequences that are specific to heterochromatin and used them to design heterochromatin specific probes ("H-probes") for microarray. By comparative genomic hybridization (CGH) analyses of embryos deficient for each chromosome or chromosome arm, we were able to map most of our H-probes to specific chromosome arms. We also positioned sequences mapped to the second and X chromosomes to finer intervals by analyzing smaller deletions with breakpoints in heterochromatin. Using this approach, we were able to map >40% (13.9 Mb) of the previously unmapped heterochromatin sequences assembled by the whole-genome sequencing effort on arm U and arm Uextra to specific locations. We also identified and mapped 110 kb of novel heterochromatic sequences. Subsequent analyses revealed that sequences located within different heterochromatic regions have distinct properties, such as sequence composition, degree of repetitiveness, and level of underreplication in polytenized tissues. Surprisingly, although heterochromatin is generally considered to be transcriptionally silent, we detected region-specific temporal patterns of transcription in heterochromatin during oogenesis and early embryonic development. Our study provides a useful approach to elucidate the molecular organization and function of heterochromatin and reveals region-specific variation of heterochromatin.

Mapping the pericentric heterochromatin by comparative genomic hybridization analysis and chromosome deletions in Drosophila melanogaster

Science.gov (United States)

He, Bing; Caudy, Amy; Parsons, Lance; Rosebrock, Adam; Pane, Attilio; Raj, Sandeep; Wieschaus, Eric

2012-01-01

Heterochromatin represents a significant portion of eukaryotic genomes and has essential structural and regulatory functions. Its molecular organization is largely unknown due to difficulties in sequencing through and assembling repetitive sequences enriched in the heterochromatin. Here we developed a novel strategy using chromosomal rearrangements and embryonic phenotypes to position unmapped Drosophila melanogaster heterochromatic sequence to specific chromosomal regions. By excluding sequences that can be mapped to the assembled euchromatic arms, we identified sequences that are specific to heterochromatin and used them to design heterochromatin specific probes (“H-probes”) for microarray. By comparative genomic hybridization (CGH) analyses of embryos deficient for each chromosome or chromosome arm, we were able to map most of our H-probes to specific chromosome arms. We also positioned sequences mapped to the second and X chromosomes to finer intervals by analyzing smaller deletions with breakpoints in heterochromatin. Using this approach, we were able to map >40% (13.9 Mb) of the previously unmapped heterochromatin sequences assembled by the whole-genome sequencing effort on arm U and arm Uextra to specific locations. We also identified and mapped 110 kb of novel heterochromatic sequences. Subsequent analyses revealed that sequences located within different heterochromatic regions have distinct properties, such as sequence composition, degree of repetitiveness, and level of underreplication in polytenized tissues. Surprisingly, although heterochromatin is generally considered to be transcriptionally silent, we detected region-specific temporal patterns of transcription in heterochromatin during oogenesis and early embryonic development. Our study provides a useful approach to elucidate the molecular organization and function of heterochromatin and reveals region-specific variation of heterochromatin. PMID:22745230

Centromeric heterochromatin: the primordial segregation machine.

Science.gov (United States)

Bloom, Kerry S

2014-01-01

Centromeres are specialized domains of heterochromatin that provide the foundation for the kinetochore. Centromeric heterochromatin is characterized by specific histone modifications, a centromere-specific histone H3 variant (CENP-A), and the enrichment of cohesin, condensin, and topoisomerase II. Centromere DNA varies orders of magnitude in size from 125 bp (budding yeast) to several megabases (human). In metaphase, sister kinetochores on the surface of replicated chromosomes face away from each other, where they establish microtubule attachment and bi-orientation. Despite the disparity in centromere size, the distance between separated sister kinetochores is remarkably conserved (approximately 1 μm) throughout phylogeny. The centromere functions as a molecular spring that resists microtubule-based extensional forces in mitosis. This review explores the physical properties of DNA in order to understand how the molecular spring is built and how it contributes to the fidelity of chromosome segregation.

Signatures of DNA target selectivity by ETS transcription factors.

Science.gov (United States)

Poon, Gregory M K; Kim, Hye Mi

2017-05-27

The ETS family of transcription factors is a functionally heterogeneous group of gene regulators that share a structurally conserved, eponymous DNA-binding domain. DNA target specificity derives from combinatorial interactions with other proteins as well as intrinsic heterogeneity among ETS domains. Emerging evidence suggests molecular hydration as a fundamental feature that defines the intrinsic heterogeneity in DNA target selection and susceptibility to epigenetic DNA modification. This perspective invokes novel hypotheses in the regulation of ETS proteins in physiologic osmotic stress, their pioneering potential in heterochromatin, and the effects of passive and pharmacologic DNA demethylation on ETS regulation.

Euchromatin islands in large heterochromatin domains are enriched for CTCF binding and differentially DNA-methylated regions

Directory of Open Access Journals (Sweden)

Wen Bo

2012-10-01

Full Text Available Abstract Background The organization of higher order chromatin is an emerging epigenetic mechanism for understanding development and disease. We and others have previously observed dynamic changes during differentiation and oncogenesis in large heterochromatin domains such as Large Organized Chromatin K (lysine modifications (LOCKs, of histone H3 lysine-9 dimethylation (H3K9me2 or other repressive histone posttranslational modifications. The microstructure of these regions has not previously been explored. Results We analyzed the genome-wide distribution of H3K9me2 in two human pluripotent stem cell lines and three differentiated cells lines. We identified > 2,500 small regions with very low H3K9me2 signals in the body of LOCKs, which were termed as euchromatin islands (EIs. EIs are 6.5-fold enriched for DNase I Hypersensitive Sites and 8-fold enriched for the binding of CTCF, the major organizer of higher-order chromatin. Furthermore, EIs are 2–6 fold enriched for differentially DNA-methylated regions associated with tissue types (T-DMRs, reprogramming (R-DMRs and cancer (C-DMRs. Gene ontology (GO analysis suggests that EI-associated genes are functionally related to organ system development, cell adhesion and cell differentiation. Conclusions We identify the existence of EIs as a finer layer of epigenomic architecture within large heterochromatin domains. Their enrichment for CTCF sites and DNAse hypersensitive sites, as well as association with DMRs, suggest that EIs play an important role in normal epigenomic architecture and its disruption in disease.

Epigenetics and lifestyle.

Science.gov (United States)

Alegría-Torres, Jorge Alejandro; Baccarelli, Andrea; Bollati, Valentina

2011-06-01

The concept of 'lifestyle' includes different factors such as nutrition, behavior, stress, physical activity, working habits, smoking and alcohol consumption. Increasing evidence shows that environmental and lifestyle factors may influence epigenetic mechanisms, such as DNA methylation, histone acetylation and miRNA expression. It has been identified that several lifestyle factors such as diet, obesity, physical activity, tobacco smoking, alcohol consumption, environmental pollutants, psychological stress and working on night shifts might modify epigenetic patterns. Most of the studies conducted so far have been centered on DNA methylation, whereas only a few investigations have studied lifestyle factors in relation to histone modifications and miRNAs. This article reviews current evidence indicating that lifestyle factors might affect human health via epigenetic mechanisms.

Border Structure of Intercalary Heterochromatin Bands of Drosophila melanogaster Polytene Chromosomes.

Science.gov (United States)

Khoroshko, V A; Zykova, T Yu; Popova, O O; Zhimulev, I F

2018-03-01

The precise genomic localization of the borders of 62 intercalary heterochromatin bands in Drosophila polytene chromosomes was determined. A new type of bands containing chromatin of different states was identified. This type is a combination of the gray band and the intercalary heterochromatin band, creating a genetic structure that with a light microscope is identified as a continuous band. The border structure of such bands includes the coding regions of genes with ubiquitous activity.

Distinct patterns of epigenetic marks and transcription factor binding ...

Indian Academy of Sciences (India)

Distinct patterns of epigenetic marks and transcription factor binding sites across promoters of sense-intronic long noncoding RNAs. Sourav Ghosh, Satish Sati, Shantanu Sengupta and Vinod Scaria. J. Genet. 94, 17–25. Gencode V9 lncRNA gene : 11004. Known lncRNA : 1175. Novel lncRNA : 5898. Putative lncRNA :.

Computational Modelling Approaches on Epigenetic Factors in Neurodegenerative and Autoimmune Diseases and Their Mechanistic Analysis

Directory of Open Access Journals (Sweden)

Afroza Khanam Irin

2015-01-01

Full Text Available Neurodegenerative as well as autoimmune diseases have unclear aetiologies, but an increasing number of evidences report for a combination of genetic and epigenetic alterations that predispose for the development of disease. This review examines the major milestones in epigenetics research in the context of diseases and various computational approaches developed in the last decades to unravel new epigenetic modifications. However, there are limited studies that systematically link genetic and epigenetic alterations of DNA to the aetiology of diseases. In this work, we demonstrate how disease-related epigenetic knowledge can be systematically captured and integrated with heterogeneous information into a functional context using Biological Expression Language (BEL. This novel methodology, based on BEL, enables us to integrate epigenetic modifications such as DNA methylation or acetylation of histones into a specific disease network. As an example, we depict the integration of epigenetic and genetic factors in a functional context specific to Parkinson’s disease (PD and Multiple Sclerosis (MS.

Epigenetic regulation in dental pulp inflammation

Science.gov (United States)

Hui, T; Wang, C; Chen, D; Zheng, L; Huang, D; Ye, L

2016-01-01

Dental caries, trauma, and other possible factors could lead to injury of the dental pulp. Dental infection could result in immune and inflammatory responses mediated by molecular and cellular events and tissue breakdown. The inflammatory response of dental pulp could be regulated by genetic and epigenetic events. Epigenetic modifications play a fundamental role in gene expression. The epigenetic events might play critical roles in the inflammatory process of dental pulp injury. Major epigenetic events include methylation and acetylation of histones and regulatory factors, DNA methylation, and small non-coding RNAs. Infections and other environmental factors have profound effects on epigenetic modifications and trigger diseases. Despite growing evidences of literatures addressing the role of epigenetics in the field of medicine and biology, very little is known about the epigenetic pathways involved in dental pulp inflammation. This review summarized the current knowledge about epigenetic mechanisms during dental pulp inflammation. Progress in studies of epigenetic alterations during inflammatory response would provide opportunities for the development of efficient medications of epigenetic therapy for pulpitis. PMID:26901577

Rumex acetosa Y chromosomes: constitutive or facultative heterochromatin?

Science.gov (United States)

Mosiołek, Magdalena; Pasierbek, Paweł; Malarz, Janusz; Moś, Maria; Joachimiak, Andrzej J

2005-01-01

Condensed Y chromosomes in Rumex acetosa L. root-tip nuclei were studied using 5-azaC treatment and immunohistochemical detection of methylated histones. Although Y chromosomes were decondensed within root meristem in vivo, they became condensed and heteropycnotic in roots cultured in vitro. 5-azacytidine (5-azaC) treatment of cultured roots caused transitional dispersion of their Y chromosome bodies, but 7 days after removal of the drug from the culture medium, Y heterochromatin recondensed and again became visible. The response of Rumex sex chromatin to 5-azaC was compared with that of condensed segments of pericentromeric heterochromatin in Rhoeo spathacea (Sw.) Steam roots. It was shown that Rhoeo chromocentres, composed of AT-rich constitutive heterochromatin, did not undergo decondensation after 5-azaC treatment. The Y-bodies observed within male nuclei of R. acetosa were globally enriched with H3 histone, demethylated at lysine 4 and methylated at lysine 9. This is the first report of histone tail-modification in condensed sex chromatin in plants. Our results suggest that the interphase condensation of Y chromosomes in Rumex is facultative rather than constitutive. Furthermore, the observed response of Y-bodies to 5-azaC may result indirectly from demethylation and the subsequent altered expression of unknown genes controlling tissue-specific Y-inactivation as opposed to the global demethylation of Y-chromosome DNA.

Epigenetic clock analysis of diet, exercise, education, and lifestyle factors.

Science.gov (United States)

Quach, Austin; Levine, Morgan E; Tanaka, Toshiko; Lu, Ake T; Chen, Brian H; Ferrucci, Luigi; Ritz, Beate; Bandinelli, Stefania; Neuhouser, Marian L; Beasley, Jeannette M; Snetselaar, Linda; Wallace, Robert B; Tsao, Philip S; Absher, Devin; Assimes, Themistocles L; Stewart, James D; Li, Yun; Hou, Lifang; Baccarelli, Andrea A; Whitsel, Eric A; Horvath, Steve

2017-02-14

Behavioral and lifestyle factors have been shown to relate to a number of health-related outcomes, yet there is a need for studies that examine their relationship to molecular aging rates. Toward this end, we use recent epigenetic biomarkers of age that have previously been shown to predict all-cause mortality, chronic conditions, and age-related functional decline. We analyze cross-sectional data from 4,173 postmenopausal female participants from the Women's Health Initiative, as well as 402 male and female participants from the Italian cohort study, Invecchiare nel Chianti.Extrinsic epigenetic age acceleration (EEAA) exhibits significant associations with fish intake (p=0.02), moderate alcohol consumption (p=0.01), education (p=3x10 -5 ), BMI (p=0.01), and blood carotenoid levels (p=1x10 -5 )-an indicator of fruit and vegetable consumption, whereas intrinsic epigenetic age acceleration (IEAA) is associated with poultry intake (p=0.03) and BMI (p=0.05). Both EEAA and IEAA were also found to relate to indicators of metabolic syndrome, which appear to mediate their associations with BMI. Metformin-the first-line medication for the treatment of type 2 diabetes-does not delay epigenetic aging in this observational study. Finally, longitudinal data suggests that an increase in BMI is associated with increase in both EEAA and IEAA.Overall, the epigenetic age analysis of blood confirms the conventional wisdom regarding the benefits of eating a high plant diet with lean meats, moderate alcohol consumption, physical activity, and education, as well as the health risks of obesity and metabolic syndrome.

Plasmodium falciparum centromeres display a unique epigenetic makeup and cluster prior to and during schizogony.

Science.gov (United States)

Hoeijmakers, Wieteke A M; Flueck, Christian; Françoijs, Kees-Jan; Smits, Arne H; Wetzel, Johanna; Volz, Jennifer C; Cowman, Alan F; Voss, Till; Stunnenberg, Hendrik G; Bártfai, Richárd

2012-09-01

Centromeres are essential for the faithful transmission of chromosomes to the next generation, therefore being essential in all eukaryotic organisms. The centromeres of Plasmodium falciparum, the causative agent of the most severe form of malaria, have been broadly mapped on most chromosomes, but their epigenetic composition remained undefined. Here, we reveal that the centromeric histone variant PfCENH3 occupies a 4-4.5 kb region on each P. falciparum chromosome, which is devoid of pericentric heterochromatin but harbours another histone variant, PfH2A.Z. These CENH3 covered regions pinpoint the exact position of the centromere on all chromosomes and revealed that all centromeric regions have similar size and sequence composition. Immunofluorescence assay of PfCENH3 strongly suggests that P. falciparum centromeres cluster to a single nuclear location prior to and during mitosis and cytokinesis but dissociate soon after invasion. In summary, we reveal a dynamic association of Plasmodium centromeres, which bear a unique epigenetic signature and conform to a strict structure. These findings suggest that DNA-associated and epigenetic elements play an important role in centromere establishment in this important human pathogen. © 2012 Blackwell Publishing Ltd.

Alteration of terminal heterochromatin and chromosome rearrangements in derivatives of wheat-rye hybrids.

Science.gov (United States)

Fu, Shulan; Lv, Zhenling; Guo, Xiang; Zhang, Xiangqi; Han, Fangpu

2013-08-20

Wheat-rye addition and substitution lines and their self progenies revealed variations in telomeric heterochromatin and centromeres. Furthermore, a mitotically unstable dicentric chromosome and stable multicentric chromosomes were observed in the progeny of a Chinese Spring-Imperial rye 3R addition line. An unstable multicentric chromosome was found in the progeny of a 6R/6D substitution line. Drastic variation of terminal heterochromatin including movement and disappearance of terminal heterochromatin occurred in the progeny of wheat-rye addition line 3R, and the 5RS ditelosomic addition line. Highly stable minichromosomes were observed in the progeny of a monosomic 4R addition line, a ditelosomic 5RS addition line and a 6R/6D substitution line. Minichromosomes, with and without the FISH signals for telomeric DNA (TTTAGGG)n, derived from a monosomic 4R addition line are stable and transmissible to the next generation. The results indicated that centromeres and terminal heterochromatin can be profoundly altered in wheat-rye hybrid derivatives. Copyright © 2013. Published by Elsevier Ltd.

Aging stem cells. A Werner syndrome stem cell model unveils heterochromatin alterations as a driver of human aging.

Science.gov (United States)

Zhang, Weiqi; Li, Jingyi; Suzuki, Keiichiro; Qu, Jing; Wang, Ping; Zhou, Junzhi; Liu, Xiaomeng; Ren, Ruotong; Xu, Xiuling; Ocampo, Alejandro; Yuan, Tingting; Yang, Jiping; Li, Ying; Shi, Liang; Guan, Dee; Pan, Huize; Duan, Shunlei; Ding, Zhichao; Li, Mo; Yi, Fei; Bai, Ruijun; Wang, Yayu; Chen, Chang; Yang, Fuquan; Li, Xiaoyu; Wang, Zimei; Aizawa, Emi; Goebl, April; Soligalla, Rupa Devi; Reddy, Pradeep; Esteban, Concepcion Rodriguez; Tang, Fuchou; Liu, Guang-Hui; Belmonte, Juan Carlos Izpisua

2015-06-05

Werner syndrome (WS) is a premature aging disorder caused by WRN protein deficiency. Here, we report on the generation of a human WS model in human embryonic stem cells (ESCs). Differentiation of WRN-null ESCs to mesenchymal stem cells (MSCs) recapitulates features of premature cellular aging, a global loss of H3K9me3, and changes in heterochromatin architecture. We show that WRN associates with heterochromatin proteins SUV39H1 and HP1α and nuclear lamina-heterochromatin anchoring protein LAP2β. Targeted knock-in of catalytically inactive SUV39H1 in wild-type MSCs recapitulates accelerated cellular senescence, resembling WRN-deficient MSCs. Moreover, decrease in WRN and heterochromatin marks are detected in MSCs from older individuals. Our observations uncover a role for WRN in maintaining heterochromatin stability and highlight heterochromatin disorganization as a potential determinant of human aging. Copyright © 2015, American Association for the Advancement of Science.

RNAi and heterochromatin repress centromeric meiotic recombination

DEFF Research Database (Denmark)

Ellermeier, Chad; Higuchi, Emily C; Phadnis, Naina

2010-01-01

During meiosis, the formation of viable haploid gametes from diploid precursors requires that each homologous chromosome pair be properly segregated to produce an exact haploid set of chromosomes. Genetic recombination, which provides a physical connection between homologous chromosomes, is essen......During meiosis, the formation of viable haploid gametes from diploid precursors requires that each homologous chromosome pair be properly segregated to produce an exact haploid set of chromosomes. Genetic recombination, which provides a physical connection between homologous chromosomes....... Surprisingly, one mutant derepressed for recombination in the heterochromatic mating-type region during meiosis and several mutants derepressed for centromeric gene expression during mitotic growth are not derepressed for centromeric recombination during meiosis. These results reveal a complex relation between...... types of repression by heterochromatin. Our results also reveal a previously undemonstrated role for RNAi and heterochromatin in the repression of meiotic centromeric recombination and, potentially, in the prevention of birth defects by maintenance of proper chromosome segregation during meiosis....

Histone hypoacetylation is required to maintain late replication timing of constitutive heterochromatin.

Science.gov (United States)

Casas-Delucchi, Corella S; van Bemmel, Joke G; Haase, Sebastian; Herce, Henry D; Nowak, Danny; Meilinger, Daniela; Stear, Jeffrey H; Leonhardt, Heinrich; Cardoso, M Cristina

2012-01-01

The replication of the genome is a spatio-temporally highly organized process. Yet, its flexibility throughout development suggests that this process is not genetically regulated. However, the mechanisms and chromatin modifications controlling replication timing are still unclear. We made use of the prominent structure and defined heterochromatic landscape of pericentric regions as an example of late replicating constitutive heterochromatin. We manipulated the major chromatin markers of these regions, namely histone acetylation, DNA and histone methylation, as well as chromatin condensation and determined the effects of these altered chromatin states on replication timing. Here, we show that manipulation of DNA and histone methylation as well as acetylation levels caused large-scale heterochromatin decondensation. Histone demethylation and the concomitant decondensation, however, did not affect replication timing. In contrast, immuno-FISH and time-lapse analyses showed that lowering DNA methylation, as well as increasing histone acetylation, advanced the onset of heterochromatin replication. While dnmt1(-)(/)(-) cells showed increased histone acetylation at chromocenters, histone hyperacetylation did not induce DNA demethylation. Hence, we propose that histone hypoacetylation is required to maintain normal heterochromatin duplication dynamics. We speculate that a high histone acetylation level might increase the firing efficiency of origins and, concomitantly, advances the replication timing of distinct genomic regions.

Heterochromatin Reorganization during Early Mouse Development Requires a Single-Stranded Noncoding Transcript

Directory of Open Access Journals (Sweden)

Miguel Casanova

2013-09-01

Full Text Available The equalization of pericentric heterochromatin from distinct parental origins following fertilization is essential for genome function and development. The recent implication of noncoding transcripts in this process raises questions regarding the connection between RNA and the nuclear organization of distinct chromatin environments. Our study addresses the interrelationship between replication and transcription of the two parental pericentric heterochromatin (PHC domains and their reorganization during early embryonic development. We demonstrate that the replication of PHC is dispensable for its clustering at the late two-cell stage. In contrast, using parthenogenetic embryos, we show that pericentric transcripts are essential for this reorganization independent of the chromatin marks associated with the PHC domains. Finally, our discovery that only reverse pericentric transcripts are required for both the nuclear reorganization of PHC and development beyond the two-cell stage challenges current views on heterochromatin organization.

Small RNA-directed epigenetic natural variation in Arabidopsis thaliana.

Directory of Open Access Journals (Sweden)

Jixian Zhai

2008-04-01

Full Text Available Progress in epigenetics has revealed mechanisms that can heritably regulate gene function independent of genetic alterations. Nevertheless, little is known about the role of epigenetics in evolution. This is due in part to scant data on epigenetic variation among natural populations. In plants, small interfering RNA (siRNA is involved in both the initiation and maintenance of gene silencing by directing DNA methylation and/or histone methylation. Here, we report that, in the model plant Arabidopsis thaliana, a cluster of approximately 24 nt siRNAs found at high levels in the ecotype Landsberg erecta (Ler could direct DNA methylation and heterochromatinization at a hAT element adjacent to the promoter of FLOWERING LOCUS C (FLC, a major repressor of flowering, whereas the same hAT element in ecotype Columbia (Col with almost identical DNA sequence, generates a set of low abundance siRNAs that do not direct these activities. We have called this hAT element MPF for Methylated region near Promoter of FLC, although de novo methylation triggered by an inverted repeat transgene at this region in Col does not alter its FLC expression. DNA methylation of the Ler allele MPF is dependent on genes in known silencing pathways, and such methylation is transmissible to Col by genetic crosses, although with varying degrees of penetrance. A genome-wide comparison of Ler and Col small RNAs identified at least 68 loci matched by a significant level of approximately 24 nt siRNAs present specifically in Ler but not Col, where nearly half of the loci are related to repeat or TE sequences. Methylation analysis revealed that 88% of the examined loci (37 out of 42 were specifically methylated in Ler but not Col, suggesting that small RNA can direct epigenetic differences between two closely related Arabidopsis ecotypes.

Rumex acetosa Y chromosomes: constitutive or facultative heterochromatin?

Directory of Open Access Journals (Sweden)

Andrzej J. Joachimiak

2011-08-01

Full Text Available Condensed Y chromosomes in Rumex acetosa L. root-tip nuclei were studied using 5-azaC treatment and immunohistochemical detection of methylated histones. Although Y chromosomes were decondensed within root meristem in vivo, they became condensed and heteropycnotic in roots cultured in vitro. 5-azacytidine (5-azaC treatment of cultured roots caused transitional dispersion of their Y chromosome bodies, but 7 days after removal of the drug from the culture medium, Y heterochromatin recondensed and again became visible. The response of Rumex sex chromatin to 5-azaC was compared with that of condensed segments of pericentromeric heterochromatin in Rhoeo spathacea (Sw. Stearn roots. It was shown that Rhoeo chromocentres, composed of AT-rich constitutive heterochromatin, did not undergo decondensation after 5-azaC treatment. The Y-bodies observed within male nuclei of R. acetosa were globally enriched with H3 histone, demethylated at lysine 4 and methylated at lysine 9. This is the first report of histone tail-modification in condensed sex chromatin in plants. Our results suggest that the interphase condensation of Y chromosomes in Rumex is facultative rather than constitutive. Furthermore, the observed response of Y-bodies to 5-azaC may result indirectly from demethylation and the subsequent altered expression of unknown genes controlling tissue-specific Y-inactivation as opposed to the global demethylation of Y-chromosome DNA.

Retroelements (LINEs and SINEs) in vole genomes: differential distribution in the constitutive heterochromatin.

Science.gov (United States)

Acosta, M J; Marchal, J A; Fernández-Espartero, C H; Bullejos, M; Sánchez, A

2008-01-01

The chromosomal distribution of mobile genetic elements is scarcely known in Arvicolinae species, but could be of relevance to understand the origin and complex evolution of the sex chromosome heterochromatin. In this work we cloned two retrotransposon sequences, L1 and SINE-B1, from the genome of Chionomys nivalis and investigated their chromosomal distribution on several arvicoline species. Our results demonstrate first that both retroelements are the most abundant repeated DNA sequences in the genome of these species. L1 elements, in most species, are highly accumulated in the sex chromosomes compared to the autosomes. This favoured L1 insertion could have played an important role in the origin of the enlarged heterochromatic blocks existing in the sex chromosomes of some Microtus species. Also, we propose that L1 accumulation on the X heterochromatin could have been the consequence of different, independent and rapid amplification processes acting in each species. SINE elements, however, were completely lacking from the constitutive heterochromatin, either in autosomes or in the heterochromatic blocks of sex chromosomes. These data could indicate that some SINE elements are incompatible with the formation of heterochromatic complexes and hence are necessarily missing from the constitutive heterochromatin.

Epigenetics in autism and other neurodevelopmental diseases.

Science.gov (United States)

Miyake, Kunio; Hirasawa, Takae; Koide, Tsuyoshi; Kubota, Takeo

2012-01-01

Autism was previously thought to be caused by environmental factors. However, genetic factors are now considered to be more contributory to the pathogenesis of autism, based on the recent findings of mutations in the genes which encode synaptic molecules associated with the communication between neurons. Epigenetic is a mechanism that controls gene expression without changing DNA sequence but by changing chromosomal histone modifications and its abnormality is associated with several neurodevelopmental diseases. Since epigenetic modifications are known to be affected by environmental factors such as nutrition, drugs and mental stress, autistic diseases are not only caused by congenital genetic defects, but may also be caused by environmental factors via epigenetic mechanism. In this chapter, we introduce autistic diseases caused by epigenetic failures and discuss epigenetic changes by environmental factors and discuss new treatments for neurodevelopmental diseases based on the recent epigenetic findings.

The expansion of heterochromatin blocks in rye reflects the co-amplification of tandem repeats and adjacent transposable elements

Czech Academy of Sciences Publication Activity Database

Evtushenko, E.V.; Levitsky, V.G.; Elisafenko, E.A.; Gunbin, K.V.; Belousov, A.I.; Šafář, Jan; Doležel, Jaroslav; Vershinin, A.V.

2016-01-01

Roč. 17, MAY 4 (2016), s. 337 ISSN 1471-2164 R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : Tandem repeats * Transposable elements * Subtelomeric heterochromatin Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.729, year: 2016

Epigenetics and Bruxism: Possible Role of Epigenetics in the Etiology of Bruxism.

Science.gov (United States)

Čalić, Aleksandra; Peterlin, Borut

2015-01-01

Bruxism is defined as a repetitive jaw muscle activity characterized by clenching or grinding of the teeth and/or bracing or thrusting of the mandible. There are two distinct circadian phenotypes for bruxism: sleep bruxism (SB) and awake bruxism, which are considered separate entities due to the putative difference in their etiology and phenotypic variance. The detailed etiology of bruxism so far remains unknown. Recent theories suggest the central regulation of certain pathophysiological or psychological pathways. Current proposed causes of bruxism appear to be a combination of genetic and environmental (G×E) factors, with epigenetics providing a robust framework for investigating G×E interactions, and their involvement in bruxism makes it a suitable candidate for epigenetic research. Both types of bruxism are associated with certain epigenetically determined disorders, such as Rett syndrome (RTT), Prader-Willi syndrome (PWS), and Angelman syndrome (AS), and these associations suggest a mechanistic link between epigenetic deregulation and bruxism. The present article reviews the possible role of epigenetic mechanisms in the etiology of both types of bruxism based on the epigenetic pathways involved in the pathophysiology of RTT, PWS, and AS, and on other epigenetic disruptions associated with risk factors for bruxism, including sleep disorders, altered stress response, and psychopathology.

Epigenetics of reproductive infertility.

Science.gov (United States)

Das, Laxmidhar; Parbin, Sabnam; Pradhan, Nibedita; Kausar, Chahat; Patra, Samir K

2017-06-01

Infertility is a complex pathophysiological condition. It may caused by specific or multiple physical and physiological factors, including abnormalities in homeostasis, hormonal imbalances and genetic alterations. In recent times various studies implicated that, aberrant epigenetic mechanisms are associated with reproductive infertility. There might be transgenerational effects associated with epigenetic modifications of gametes and studies suggest the importance of alterations in epigenetic modification at early and late stages of gametogenesis. To determine the causes of infertility it is necessary to understand the altered epigenetic modifications of associated gene and mechanisms involved therein. This review is devoted to elucidate the recent mechanistic advances in regulation of genes by epigenetic modification and emphasizes their possible role related to reproductive infertility. It includes environmental, nutritional, hormonal and physiological factors and influence of internal structural architecture of chromatin nucleosomes affecting DNA and histone modifications in both male and female gametes, early embryogenesis and offspring. Finally, we would like to emphasize that research on human infertility by gene knock out of epigenetic modifiers genes must be relied upon animal models.

Epigenetics and obesity.

Science.gov (United States)

Campión, Javier; Milagro, Fermin; Martínez, J Alfredo

2010-01-01

The etiology of obesity is multifactorial, involving complex interactions among the genetic makeup, neuroendocrine status, fetal programming, and different unhealthy environmental factors, such as sedentarism or inadequate dietary habits. Among the different mechanisms causing obesity, epigenetics, defined as the study of heritable changes in gene expression that occur without a change in the DNA sequence, has emerged as a very important determinant. Experimental evidence concerning dietary factors influencing obesity development through epigenetic mechanisms has been described. Thus, identification of those individuals who present with changes in DNA methylation profiles, certain histone modifications, or other epigenetically related processes could help to predict their susceptibility to gain or lose weight. Indeed, research concerning epigenetic mechanisms affecting weight homeostasis may play a role in the prevention of excessive fat deposition, the prediction of the most appropriate weight reduction plan, and the implementation of newer therapeutic approaches. Copyright © 2010 Elsevier Inc. All rights reserved.

Epigenetics of autism spectrum disorders.

Science.gov (United States)

Schanen, N Carolyn

2006-10-15

The autism spectrum disorders (ASD) comprise a complex group of behaviorally related disorders that are primarily genetic in origin. Involvement of epigenetic regulatory mechanisms in the pathogenesis of ASD has been suggested by the occurrence of ASD in patients with disorders arising from epigenetic mutations (fragile X syndrome) or that involve key epigenetic regulatory factors (Rett syndrome). Moreover, the most common recurrent cytogenetic abnormalities in ASD involve maternally derived duplications of the imprinted domain on chromosome 15q11-13. Thus, parent of origin effects on sharing and linkage to imprinted regions on chromosomes 15q and 7q suggest that these regions warrant specific examination from an epigenetic perspective, particularly because epigenetic modifications do not change the primary genomic sequence, allowing risk epialleles to evade detection using standard screening strategies. This review examines the potential role of epigenetic factors in the etiology of ASD.

Landscaping plant epigenetics.

Science.gov (United States)

McKeown, Peter C; Spillane, Charles

2014-01-01

The understanding of epigenetic mechanisms is necessary for assessing the potential impacts of epigenetics on plant growth, development and reproduction, and ultimately for the response of these factors to evolutionary pressures and crop breeding programs. This volume highlights the latest in laboratory and bioinformatic techniques used for the investigation of epigenetic phenomena in plants. Such techniques now allow genome-wide analyses of epigenetic regulation and help to advance our understanding of how epigenetic regulatory mechanisms affect cellular and genome function. To set the scene, we begin with a short background of how the field of epigenetics has evolved, with a particular focus on plant epigenetics. We consider what has historically been understood by the term "epigenetics" before turning to the advances in biochemistry, molecular biology, and genetics which have led to current-day definitions of the term. Following this, we pay attention to key discoveries in the field of epigenetics that have emerged from the study of unusual and enigmatic phenomena in plants. Many of these phenomena have involved cases of non-Mendelian inheritance and have often been dismissed as mere curiosities prior to the elucidation of their molecular mechanisms. In the penultimate section, consideration is given to how advances in molecular techniques are opening the doors to a more comprehensive understanding of epigenetic phenomena in plants. We conclude by assessing some opportunities, challenges, and techniques for epigenetic research in both model and non-model plants, in particular for advancing understanding of the regulation of genome function by epigenetic mechanisms.

Arabidopsis HDA6 regulates locus-directed heterochromatin silencing in cooperation with MET1.

OpenAIRE

Taiko Kim To; Jong-Myong Kim; Akihiro Matsui; Yukio Kurihara; Taeko Morosawa; Junko Ishida; Maho Tanaka; Takaho Endo; Tetsuji Kakutani; Tetsuro Toyoda; Hiroshi Kimura; Shigeyuki Yokoyama; Kazuo Shinozaki; Motoaki Seki

2011-01-01

Heterochromatin silencing is pivotal for genome stability in eukaryotes. In Arabidopsis, a plant-specific mechanism called RNA–directed DNA methylation (RdDM) is involved in heterochromatin silencing. Histone deacetylase HDA6 has been identified as a component of such machineries; however, its endogenous targets and the silencing mechanisms have not been analyzed globally. In this study, we investigated the silencing mechanism mediated by HDA6. Genome-wide transcript profiling revealed that t...

Nuclear Architecture of Mouse Spermatocytes: Chromosome Topology, Heterochromatin, and Nucleolus.

Science.gov (United States)

Berrios, Soledad

2017-01-01

The nuclear organization of spermatocytes in meiotic prophase I is primarily determined by the synaptic organization of the bivalents that are bound by their telomeres to the nuclear envelope and described as arc-shaped trajectories through the 3D nuclear space. However, over this basic meiotic organization, a spermatocyte nuclear architecture arises that is based on higher-ordered patterns of spatial associations among chromosomal domains from different bivalents that are conditioned by the individual characteristics of chromosomes and the opportunity for interactions between their domains. Consequently, the nuclear architecture is species-specific and prone to modification by chromosomal rearrangements. This model is valid for the localization of any chromosomal domain in the meiotic prophase nucleus. However, constitutive heterochromatin plays a leading role in shaping nuclear territories. Thus, the nuclear localization of nucleoli depends on the position of NORs in nucleolar bivalents, but the association among nucleolar chromosomes mainly depends on the presence of constitutive heterochromatin that does not affect the expression of the ribosomal genes. Constitutive heterochromatin and nucleoli form complex nuclear territories whose distribution in the nuclear space is nonrandom, supporting the hypothesis regarding the existence of a species-specific nuclear architecture in first meiotic prophase spermatocytes. © 2017 S. Karger AG, Basel.

EPA Workshop on Epigenetics and Cumulative Risk ...

Science.gov (United States)

Agenda Download the Workshop Agenda (PDF) The workshop included presentations and discussions by scientific experts pertaining to three topics (i.e., epigenetic changes associated with diverse stressors, key science considerations in understanding epigenetic changes, and practical application of epigenetic tools to address cumulative risks from environmental stressors), to address several questions under each topic, and included an opportunity for attendees to participate in break-out groups, provide comments and ask questions. Workshop Goals The workshop seeks to examine the opportunity for use of aggregate epigenetic change as an indicator in cumulative risk assessment for populations exposed to multiple stressors that affect epigenetic status. Epigenetic changes are specific molecular changes around DNA that alter expression of genes. Epigenetic changes include DNA methylation, formation of histone adducts, and changes in micro RNAs. Research today indicates that epigenetic changes are involved in many chronic diseases (cancer, cardiovascular disease, obesity, diabetes, mental health disorders, and asthma). Research has also linked a wide range of stressors including pollution and social factors with occurrence of epigenetic alterations. Epigenetic changes have the potential to reflect impacts of risk factors across multiple stages of life. Only recently receiving attention is the nexus between the factors of cumulative exposure to environmental

Prostate Cancer: Epigenetic Alterations, Risk Factors, and Therapy

Directory of Open Access Journals (Sweden)

Mankgopo M. Kgatle

2016-01-01

Full Text Available Prostate cancer (PCa is the most prevalent urological cancer that affects aging men in South Africa, and mechanisms underlying prostate tumorigenesis remain elusive. Research advancements in the field of PCa and epigenetics have allowed for the identification of specific alterations that occur beyond genetics but are still critically important in the pathogenesis of tumorigenesis. Anomalous epigenetic changes associated with PCa include histone modifications, DNA methylation, and noncoding miRNA. These mechanisms regulate and silence hundreds of target genes including some which are key components of cellular signalling pathways that, when perturbed, promote tumorigenesis. Elucidation of mechanisms underlying epigenetic alterations and the manner in which these mechanisms interact in regulating gene transcription in PCa are an unmet necessity that may lead to novel chemotherapeutic approaches. This will, therefore, aid in developing combination therapies that will target multiple epigenetic pathways, which can be used in conjunction with the current conventional PCa treatment.

Epigenetic Mechanisms and Therapeutic Perspectives for Neurodevelopmental Disorders

Directory of Open Access Journals (Sweden)

Kunio Miyake

2012-04-01

Full Text Available The number of children with mild neurodevelopmental disorders, such as autism, has been recently increasing in advanced countries. This increase is probably caused by environmental factors rather than genetic factors, because it is unlikely that genetic mutation rates suddenly increased within a short period. Epigenetics is a mechanism that regulates gene expression, depending not on the underlying DNA sequence but on the chemical modifications of DNA and histone proteins. Because mental stress can alter the epigenetic status in neuronal cells, environmental factors may alter brain function through epigenetic changes. However, one advantage of epigenetic changes is their reversibility. Therefore, diseases due to abnormal epigenetic regulation are theoretically treatable. In fact, several drugs for treating mental diseases are known to have restoring effects on aberrant epigenetic statuses, and a novel therapeutic strategy targeting gene has been developed. In this review, we discuss epigenetic mechanisms of congenital and acquired neurodevelopmental disorders, drugs with epigenetic effects, novel therapeutic strategies for epigenetic diseases, and future perspectives in epigenetic medicine.

Positive Selection Drives the Evolution of rhino, a Member of the Heterochromatin Protein 1 Family in Drosophila.

Directory of Open Access Journals (Sweden)

2005-07-01

Full Text Available Heterochromatin comprises a significant component of many eukaryotic genomes. In comparison to euchromatin, heterochromatin is gene poor, transposon rich, and late replicating. It serves many important biological roles, from gene silencing to accurate chromosome segregation, yet little is known about the evolutionary constraints that shape heterochromatin. A complementary approach to the traditional one of directly studying heterochromatic DNA sequence is to study the evolution of proteins that bind and define heterochromatin. One of the best markers for heterochromatin is the heterochromatin protein 1 (HP1, which is an essential, nonhistone chromosomal protein. Here we investigate the molecular evolution of five HP1 paralogs present in Drosophila melanogaster. Three of these paralogs have ubiquitous expression patterns in adult Drosophila tissues, whereas HP1D/rhino and HP1E are expressed predominantly in ovaries and testes respectively. The HP1 paralogs also have distinct localization preferences in Drosophila cells. Thus, Rhino localizes to the heterochromatic compartment in Drosophila tissue culture cells, but in a pattern distinct from HP1A and lysine-9 dimethylated H3. Using molecular evolution and population genetic analyses, we find that rhino has been subject to positive selection in all three domains of the protein: the N-terminal chromo domain, the C-terminal chromo-shadow domain, and the hinge region that connects these two modules. Maximum likelihood analysis of rhino sequences from 20 species of Drosophila reveals that a small number of residues of the chromo and shadow domains have been subject to repeated positive selection. The rapid and positive selection of rhino is highly unusual for a gene encoding a chromosomal protein and suggests that rhino is involved in a genetic conflict that affects the germline, belying the notion that heterochromatin is simply a passive recipient of "junk DNA" in eukaryotic genomes.

Positive selection drives the evolution of rhino, a member of the heterochromatin protein 1 family in Drosophila.

Directory of Open Access Journals (Sweden)

Danielle Vermaak

2005-07-01

Full Text Available Heterochromatin comprises a significant component of many eukaryotic genomes. In comparison to euchromatin, heterochromatin is gene poor, transposon rich, and late replicating. It serves many important biological roles, from gene silencing to accurate chromosome segregation, yet little is known about the evolutionary constraints that shape heterochromatin. A complementary approach to the traditional one of directly studying heterochromatic DNA sequence is to study the evolution of proteins that bind and define heterochromatin. One of the best markers for heterochromatin is the heterochromatin protein 1 (HP1, which is an essential, nonhistone chromosomal protein. Here we investigate the molecular evolution of five HP1 paralogs present in Drosophila melanogaster. Three of these paralogs have ubiquitous expression patterns in adult Drosophila tissues, whereas HP1D/rhino and HP1E are expressed predominantly in ovaries and testes respectively. The HP1 paralogs also have distinct localization preferences in Drosophila cells. Thus, Rhino localizes to the heterochromatic compartment in Drosophila tissue culture cells, but in a pattern distinct from HP1A and lysine-9 dimethylated H3. Using molecular evolution and population genetic analyses, we find that rhino has been subject to positive selection in all three domains of the protein: the N-terminal chromo domain, the C-terminal chromo-shadow domain, and the hinge region that connects these two modules. Maximum likelihood analysis of rhino sequences from 20 species of Drosophila reveals that a small number of residues of the chromo and shadow domains have been subject to repeated positive selection. The rapid and positive selection of rhino is highly unusual for a gene encoding a chromosomal protein and suggests that rhino is involved in a genetic conflict that affects the germline, belying the notion that heterochromatin is simply a passive recipient of "junk DNA" in eukaryotic genomes.

Heterochromatin and molecular characterization of DsmarMITE transposable element in the beetle Dichotomius schiffleri (Coleoptera: Scarabaeidae).

Science.gov (United States)

Xavier, Crislaine; Cabral-de-Mello, Diogo Cavalcanti; de Moura, Rita Cássia

2014-12-01

Cytogenetic studies of the Neotropical beetle genus Dichotomius (Scarabaeinae, Coleoptera) have shown dynamism for centromeric constitutive heterochromatin sequences. In the present work we studied the chromosomes and isolated repetitive sequences of Dichotomius schiffleri aiming to contribute to the understanding of coleopteran genome/chromosomal organization. Dichotomius schiffleri presented a conserved karyotype and heterochromatin distribution in comparison to other species of the genus with 2n = 18, biarmed chromosomes, and pericentromeric C-positive blocks. Similarly to heterochromatin distributional patterns, the highly and moderately repetitive DNA fraction (C 0 t-1 DNA) was detected in pericentromeric areas, contrasting with the euchromatic mapping of an isolated TE (named DsmarMITE). After structural analyses, the DsmarMITE was classified as a non-autonomous element of the type miniature inverted-repeat transposable element (MITE) with terminal inverted repeats similar to Mariner elements of insects from different orders. The euchromatic distribution for DsmarMITE indicates that it does not play a part in the dynamics of constitutive heterochromatin sequences.

Obesity: epigenetic aspects.

Science.gov (United States)

Kaushik, Prashant; Anderson, James T

2016-06-01

Epigenetics, defined as inheritable and reversible phenomena that affect gene expression without altering the underlying base pair sequence has been shown to play an important role in the etiopathogenesis of obesity. Obesity is associated with extensive gene expression changes in tissues throughout the body. Epigenetics is emerging as perhaps the most important mechanism through which the lifestyle-choices we make can directly influence the genome. Considerable epidemiological, experimental and clinical data have been amassed showing that the risk of developing disease in later life is dependent on early life conditions, mainly operating within the normative range of developmental exposures. In addition to the 'maternal' interactions, there has been increasing interest in the epigenetic mechanisms through which 'paternal' influences on offspring development can be achieved. Nutrition, among many other environmental factors, is a key player that can induce epigenetic changes not only in the directly exposed organisms but also in subsequent generations through the transgenerational inheritance of epigenetic traits. Overall, significant progress has been made in the field of epigenetics and obesity and the first potential epigenetic markers for obesity that could be detected at birth have been identified. Fortunately, epigenetic phenomena are dynamic and rather quickly reversible with intensive lifestyle changes. This is a very promising and sustainable resolution to the obesity pandemic.

Heterochromatin protein 1 gamma and IκB kinase alpha interdependence during tumour necrosis factor gene transcription elongation in activated macrophages.

Science.gov (United States)

Thorne, James L; Ouboussad, Lylia; Lefevre, Pascal F

2012-09-01

IκB kinase α (IKKα) is part of the cytoplasmic IKK complex regulating nuclear factor-κB (NF-κB) release and translocation into the nucleus in response to pro-inflammatory signals. IKKα can also be recruited directly to the promoter of NF-κB-dependent genes by NF-κB where it phosphorylates histone H3 at serine 10, triggering recruitment of the bromodomain-containing protein 4 and the positive transcription elongation factor b. Herein, we report that IKKα travels with the elongating form of ribonucleic acid polymerase II together with heterochromatin protein 1 gamma (HP1γ) at NF-κB-dependent genes in activated macrophages. IKKα binds to and phosphorylates HP1γ, which in turn controls IKKα binding to chromatin and phosphorylation of the histone variant H3.3 at serine 31 within transcribing regions. Downstream of transcription end sites, IKKα accumulates with its inhibitor the CUE-domain containing protein 2, suggesting a link between IKKα inactivation and transcription termination.

Dietary factors and epigenetic regulation for prostate cancer prevention.

Science.gov (United States)

Ho, Emily; Beaver, Laura M; Williams, David E; Dashwood, Roderick H

2011-11-01

The role of epigenetic alterations in various human chronic diseases has gained increasing attention and has resulted in a paradigm shift in our understanding of disease susceptibility. In the field of cancer research, e.g., genetic abnormalities/mutations historically were viewed as primary underlying causes; however, epigenetic mechanisms that alter gene expression without affecting DNA sequence are now recognized as being of equal or greater importance for oncogenesis. Methylation of DNA, modification of histones, and interfering microRNA (miRNA) collectively represent a cadre of epigenetic elements dysregulated in cancer. Targeting the epigenome with compounds that modulate DNA methylation, histone marks, and miRNA profiles represents an evolving strategy for cancer chemoprevention, and these approaches are starting to show promise in human clinical trials. Essential micronutrients such as folate, vitamin B-12, selenium, and zinc as well as the dietary phytochemicals sulforaphane, tea polyphenols, curcumin, and allyl sulfur compounds are among a growing list of agents that affect epigenetic events as novel mechanisms of chemoprevention. To illustrate these concepts, the current review highlights the interactions among nutrients, epigenetics, and prostate cancer susceptibility. In particular, we focus on epigenetic dysregulation and the impact of specific nutrients and food components on DNA methylation and histone modifications that can alter gene expression and influence prostate cancer progression.

Fetal programming of Parkinson’s and Alzheimer’s diseases: the role of epigenetic factors

Directory of Open Access Journals (Sweden)

Monica Piras

2014-06-01

Full Text Available In this paper, the main epigenetic factors involved in shaping the brain’s physical structure during development will be reviewed, with special emphasis on those related to Parkinson’s disease and Alzheimer’s disease in adulthood. These factors are: preterm delivery, maternal diet, trace metals, intrauterine infection, maternal stress, drugs, alcohol. Epigenetics may allow a novel therapeutic and preventive approach for neurodegeneration. Proceedings of the 10th International Workshop on Neonatology · Cagliari (Italy · October 22nd-25th, 2014 · The last ten years, the next ten years in Neonatology Guest Editors: Vassilios Fanos, Michele Mussap, Gavino Faa, Apostolos Papageorgiou

The epigenetic regulation of stem cell factors in hepatic stellate cells.

Science.gov (United States)

Reister, Sven; Kordes, Claus; Sawitza, Iris; Häussinger, Dieter

2011-10-01

The epigenetic regulation by DNA methylation is an important mechanism to control the expression of stem cell factors as demonstrated in tumor cells. It was recently shown that hepatic stellate cells (HSC) express stem/progenitor cell factors and have a differentiation potential. The aim of this work was to investigate if the expression of stem cell markers is regulated by DNA methylation during activation of rat HSC. It was found that CD133, Notch1, and Notch3 are regulated via DNA methylation in HSC, whereas Nestin shows no DNA methylation in HSC and other undifferentiated cells such as embryonic stem cells and umbilical cord blood stem cells from rats. In contrast to this, DNA methylation controls Nestin expression in differentiated cells like hepatocytes and the hepatoma cell line H4IIE. Demethylation by 5-Aza-2-deoxycytidine was sufficient to induce Nestin in H4IIE cells. In quiescent stellate cells and embryonic stem cells, the Nestin expression was suppressed by histone H3 methylation at lysine 9, which is another epigenetic mechanism. Apart from the known induction of Nestin in cultured HSC, this intermediate filament protein was also induced after partial hepatectomy, indicating activation of HSC during liver regeneration. Taken together, this study demonstrates for the first time that the expression of stem cell-associated factors such as CD133, Notch1, and Notch3 is controlled by DNA methylation in HSC. The regulation of Nestin by DNA methylation seems to be restricted to differentiated cells, whereas undifferentiated cells use different epigenetic mechanisms such as histone H3 methylation to control Nestin expression.

Understanding Neurological Disease Mechanisms in the Era of Epigenetics

Science.gov (United States)

Qureshi, Irfan A.; Mehler, Mark F.

2015-01-01

The burgeoning field of epigenetics is making a significant impact on our understanding of brain evolution, development, and function. In fact, it is now clear that epigenetic mechanisms promote seminal neurobiological processes, ranging from neural stem cell maintenance and differentiation to learning and memory. At the molecular level, epigenetic mechanisms regulate the structure and activity of the genome in response to intracellular and environmental cues, including the deployment of cell type–specific gene networks and those underlying synaptic plasticity. Pharmacological and genetic manipulation of epigenetic factors can, in turn, induce remarkable changes in neural cell identity and cognitive and behavioral phenotypes. Not surprisingly, it is also becoming apparent that epigenetics is intimately involved in neurological disease pathogenesis. Herein, we highlight emerging paradigms for linking epigenetic machinery and processes with neurological disease states, including how (1) mutations in genes encoding epigenetic factors cause disease, (2) genetic variation in genes encoding epigenetic factors modify disease risk, (3) abnormalities in epigenetic factor expression, localization, or function are involved in disease pathophysiology, (4) epigenetic mechanisms regulate disease-associated genomic loci, gene products, and cellular pathways, and (5) differential epigenetic profiles are present in patient-derived central and peripheral tissues. PMID:23571666

[Epigenetics of schizophrenia: a review].

Science.gov (United States)

Rivollier, F; Lotersztajn, L; Chaumette, B; Krebs, M-O; Kebir, O

2014-10-01

Schizophrenia is a frequent and disabling disease associated with heterogeneous psychiatric phenotypes. It emerges during childhood, adolescence or young adulthood and has dramatic consequences for the affected individuals, causing considerable familial and social burden, as well as increasing health expenses. Although some progress has been made in the understanding of their physiopathology, many questions remain unsolved, and the disease is still poorly understood. The prevailing hypothesis regarding psychotic disorders proposes that a combination of genetic and/or environmental factors, during critical periods of brain development increases the risk for these illnesses. Epigenetic regulations, such as DNA methylation, can mediate gene x environment interactions at the level of the genome and may provide a potential substrate to explain the variability in symptom severity and family heritability. Initially, epigenetics was used to design mitotic and meiotic changes in gene transcription that could not be attributed to genetic mutations. It referred later to changes in the epigenome not transmitted through the germline. Thus, epigenetics refers to a wide range of molecular mechanisms including DNA methylation of cytosine residues in CpG dinucleotides and post-translational histone modifications. These mechanisms alter the way the transcriptional factors bind the DNA, modulating its expression. Prenatal and postnatal environmental factors may affect these epigenetics factors, having responsability in long-term DNA transcription, and influencing the development of psychiatric disorders. The object of this review is to present the state of knowledge in epigenetics of schizophrenia, outlining the most recent findings in the matter. We did so using Pubmed, researching words such as 'epigenetics', 'epigenetic', 'schizophrenia', 'psychosis', 'psychiatric'. This review summarizes evidences mostly for two epigenetic mechanisms: DNA methylation and post

Mapping the pericentric heterochromatin by comparative genomic hybridization analysis and chromosome deletions in Drosophila melanogaster

OpenAIRE

He, Bing; Caudy, Amy; Parsons, Lance; Rosebrock, Adam; Pane, Attilio; Raj, Sandeep; Wieschaus, Eric

2012-01-01

Heterochromatin represents a significant portion of eukaryotic genomes and has essential structural and regulatory functions. Its molecular organization is largely unknown due to difficulties in sequencing through and assembling repetitive sequences enriched in the heterochromatin. Here we developed a novel strategy using chromosomal rearrangements and embryonic phenotypes to position unmapped Drosophila melanogaster heterochromatic sequence to specific chromosomal regions. By excluding seque...

Epigenetic regulation in obesity.

Science.gov (United States)

Drummond, Elaine M; Gibney, Eileen R

2013-07-01

Research suggests that 65% of variation in obesity is genetic. However, much of the known genetic associations have little known function and their effect size small, thus the gene-environment interaction, including epigenetic influences on gene expression, is suggested to be an important factor in the susceptibilty to obesity. This review will explore the potential of epigenetic markers to influence expression of genes associated with obesity. Epigenetic changes in utero are known to have direct implications on the phenotype of the offspring. More recently work has focused on how such epigenetic changes continue to regulate risk of obesity from infancy through to adulthood. Work has shown that, for example, hypomethylation of the MC4 gene causes an increase in expression, and has a direct impact on appetite and intake, and thus influences risk of obesity. Similar influences are also seen in other aspects of obesity including inflammation and adiposity. Maternal diet during foetal development has many epigenetic implications, which affect the offspring's risk factors for obesity during childhood and adulthood, and even in subsequent generations. Genes associated with risk of obesity, are susceptible to epigenetic mutations, which have subsequent effects on disease mechanisms, such as appetite and impaired glucose and insulin tolerance.

Epigenetic Pathways of Oncogenic Viruses: Therapeutic Promises.

Science.gov (United States)

El-Araby, Amr M; Fouad, Abdelrahman A; Hanbal, Amr M; Abdelwahab, Sara M; Qassem, Omar M; El-Araby, Moustafa E

2016-02-01

Cancerous transformation comprises different events that are both genetic and epigenetic. The ultimate goal for such events is to maintain cell survival and proliferation. This transformation occurs as a consequence of different features such as environmental and genetic factors, as well as some types of infection. Many viral infections are considered to be causative agents of a number of different malignancies. To convert normal cells into cancerous cells, oncogenic viruses must function at the epigenetic level to communicate with their host cells. Oncogenic viruses encode certain epigenetic factors that lead to the immortality and proliferation of infected cells. The epigenetic effectors produced by oncogenic viruses constitute appealing targets to prevent and treat malignant diseases caused by these viruses. In this review, we highlight the importance of epigenetic reprogramming for virus-induced oncogenesis, with special emphasis on viral epigenetic oncoproteins as therapeutic targets. The discovery of molecular components that target epigenetic pathways, especially viral factors, is also discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Drugs affecting prelamin A processing: Effects on heterochromatin organization

International Nuclear Information System (INIS)

Mattioli, Elisabetta; Columbaro, Marta; Capanni, Cristina; Santi, Spartaco; Maraldi, Nadir M.; D'Apice, M. Rosaria; Novelli, Giuseppe; Riccio, Massimo; Squarzoni, Stefano; Foisner, Roland; Lattanzi, Giovanna

2008-01-01

Increasing interest in drugs acting on prelamin A has derived from the finding of prelamin A involvement in severe laminopathies. Amelioration of the nuclear morphology by inhibitors of prelamin A farnesylation has been widely reported in progeroid laminopathies. We investigated the effects on chromatin organization of two drugs inhibiting prelamin A processing by an ultrastructural and biochemical approach. The farnesyltransferase inhibitor FTI-277 and the non-peptidomimetic drug N-acetyl-S-farnesyl-L-cysteine methylester (AFCMe) were administered to cultured control human fibroblasts for 6 or 18 h. FTI-277 interferes with protein farnesylation causing accumulation of non-farnesylated prelamin A, while AFCMe impairs the last cleavage of the lamin A precursor and is expected to accumulate farnesylated prelamin A. FTI-277 caused redistribution of heterochromatin domains at the nuclear interior, while AFCMe caused loss of heterochromatin domains, increase of nuclear size and nuclear lamina thickening. At the biochemical level, heterochromatin-associated proteins and LAP2α were clustered at the nuclear interior following FTI-277 treatment, while they were unevenly distributed or absent in AFCMe-treated nuclei. The reported effects show that chromatin is an immediate target of FTI-277 and AFCMe and that dramatic remodeling of chromatin domains occurs following treatment with the drugs. These effects appear to depend, at least in part, on the accumulation of prelamin A forms, since impairment of prelamin A accumulation, here obtained by 5-azadeoxycytidine treatment, abolishes the chromatin effects. These results may be used to evaluate downstream effects of FTIs or other prelamin A inhibitors potentially useful for the therapy of laminopathies

Behavioral epigenetics.

Science.gov (United States)

Moore, David S

2017-01-01

Why do we grow up to have the traits we do? Most 20th century scientists answered this question by referring only to our genes and our environments. But recent discoveries in the emerging field of behavioral epigenetics have revealed factors at the interface between genes and environments that also play crucial roles in development. These factors affect how genes work; scientists now know that what matters as much as which genes you have (and what environments you encounter) is how your genes are affected by their contexts. The discovery that what our genes do depends in part on our experiences has shed light on how Nature and Nurture interact at the molecular level inside of our bodies. Data emerging from the world's behavioral epigenetics laboratories support the idea that a person's genes alone cannot determine if, for example, he or she will end up shy, suffering from cardiovascular disease, or extremely smart. Among the environmental factors that can influence genetic activity are parenting styles, diets, and social statuses. In addition to influencing how doctors treat diseases, discoveries about behavioral epigenetics are likely to alter how biologists think about evolution, because some epigenetic effects of experience appear to be transmissible from generation to generation. This domain of research will likely change how we think about the origins of human nature. WIREs Syst Biol Med 2017, 9:e1333. doi: 10.1002/wsbm.1333 For further resources related to this article, please visit the WIREs website. © 2016 Wiley Periodicals, Inc.

Epigenetic Alterations in Alzheimer's Disease

Directory of Open Access Journals (Sweden)

Johannes eGräff

2015-12-01

Full Text Available Alzheimer’s disease (AD is the major cause of dementia in Western societies. It progresses asymptomatically during decades before being belatedly diagnosed when therapeutic strategies have become unviable. Although several genetic alterations have been associated with AD, the vast majority of AD cases do not show strong genetic underpinnings and are thus considered a consequence of non-genetic factors. Epigenetic mechanisms allow for the integration of long-lasting non-genetic inputs on specific genetic backgrounds, and recently, a growing number of epigenetic alterations in AD have been described. For instance, an accumulation of dysregulated epigenetic mechanisms in aging, the predominant risk factor of AD, might facilitate the onset of the disease. Likewise, mutations in several enzymes of the epigenetic machinery have been associated with neurodegenerative processes that are altered in AD such as impaired learning and memory formation. Genome-wide and locus-specific epigenetic alterations have also been reported, and several epigenetically dysregulated genes validated by independent groups. From these studies, a picture emerges of AD as being associated with DNA hypermethylation and histone deacetylation, suggesting a general repressed chromatin state and epigenetically reduced plasticity in AD. Here we review these recent findings and discuss several technical and methodological considerations that are imperative for their correct interpretation. We also pay particular focus on potential implementations and theoretical frameworks that we expect will help to better direct future studies aimed to unravel the epigenetic participation in AD.

Epigenetic Alterations in Alzheimer's Disease.

Science.gov (United States)

Sanchez-Mut, Jose V; Gräff, Johannes

2015-01-01

Alzheimer's disease (AD) is the major cause of dementia in Western societies. It progresses asymptomatically during decades before being belatedly diagnosed when therapeutic strategies have become unviable. Although several genetic alterations have been associated with AD, the vast majority of AD cases do not show strong genetic underpinnings and are thus considered a consequence of non-genetic factors. Epigenetic mechanisms allow for the integration of long-lasting non-genetic inputs on specific genetic backgrounds, and recently, a growing number of epigenetic alterations in AD have been described. For instance, an accumulation of dysregulated epigenetic mechanisms in aging, the predominant risk factor of AD, might facilitate the onset of the disease. Likewise, mutations in several enzymes of the epigenetic machinery have been associated with neurodegenerative processes that are altered in AD such as impaired learning and memory formation. Genome-wide and locus-specific epigenetic alterations have also been reported, and several epigenetically dysregulated genes validated by independent groups. From these studies, a picture emerges of AD as being associated with DNA hypermethylation and histone deacetylation, suggesting a general repressed chromatin state and epigenetically reduced plasticity in AD. Here we review these recent findings and discuss several technical and methodological considerations that are imperative for their correct interpretation. We also pay particular focus on potential implementations and theoretical frameworks that we expect will help to better direct future studies aimed to unravel the epigenetic participation in AD.

Engrampigenetics: Epigenetics of engram memory cells.

Science.gov (United States)

Ripoli, Cristian

2017-05-15

For long time, the epidemiology of late-onset sporadic Alzheimer's disease (AD) risk factors has centered on adult life-style. Recent studies have, instead, focused on the role of early life experiences in progression of such disease especially in the context of prenatal and postnatal life. Although no single unfavorable environmental event has been shown to be neither necessary nor sufficient for AD development, it is possible that the sum of several environmentally induced effects, over time, contribute to its pathophysiology through epigenetic mechanisms. Indeed, epigenetic changes are influenced by environmental factors and have been proposed to play a role in multifactorial pathologies such as AD. At the same time, recent findings suggest that epigenetic mechanisms are one method that neurons use to translate transient stimuli into stable memories. Thus, the characteristics of epigenetics being a critical link between the environment and genes and playing a crucial role in memory formation make candidate epigenetic mechanisms a natural substrate for AD research. Indeed, independent groups have reported several epigenetically dysregulated genes in AD models; however, the role of epigenetic mechanisms in AD has remained elusive owing to contradictory results. Here, I propose that restricting the analysis of epigenetic changes specifically to subpopulations of neurons (namely, engram memory cells) might be helpful in understanding the role of the epigenetic process in the memory-related specific epigenetic code and might constitute a new template for therapeutic interventions against AD. Copyright © 2016. Published by Elsevier B.V.

Gene expression and stress response mediated by the epigenetic regulation of a transposable element small RNA.

Directory of Open Access Journals (Sweden)

Andrea D McCue

2012-02-01

Full Text Available The epigenetic activity of transposable elements (TEs can influence the regulation of genes; though, this regulation is confined to the genes, promoters, and enhancers that neighbor the TE. This local cis regulation of genes therefore limits the influence of the TE's epigenetic regulation on the genome. TE activity is suppressed by small RNAs, which also inhibit viruses and regulate the expression of genes. The production of TE heterochromatin-associated endogenous small interfering RNAs (siRNAs in the reference plant Arabidopsis thaliana is mechanistically distinct from gene-regulating small RNAs, such as microRNAs or trans-acting siRNAs (tasiRNAs. Previous research identified a TE small RNA that potentially regulates the UBP1b mRNA, which encodes an RNA-binding protein involved in stress granule formation. We demonstrate that this siRNA, siRNA854, is under the same trans-generational epigenetic control as the Athila family LTR retrotransposons from which it is produced. The epigenetic activation of Athila elements results in a shift in small RNA processing pathways, and new 21-22 nucleotide versions of Athila siRNAs are produced by protein components normally not responsible for processing TE siRNAs. This processing results in siRNA854's incorporation into ARGONAUTE1 protein complexes in a similar fashion to gene-regulating tasiRNAs. We have used reporter transgenes to demonstrate that the UPB1b 3' untranslated region directly responds to the epigenetic status of Athila TEs and the accumulation of siRNA854. The regulation of the UPB1b 3' untranslated region occurs both on the post-transcriptional and translational levels when Athila TEs are epigenetically activated, and this regulation results in the phenocopy of the ubp1b mutant stress-sensitive phenotype. This demonstrates that a TE's epigenetic activity can modulate the host organism's stress response. In addition, the ability of this TE siRNA to regulate a gene's expression in trans blurs

Prostate cancer: The main risk and protective factors-Epigenetic modifications.

Science.gov (United States)

Adjakly, Mawussi; Ngollo, Marjolaine; Dagdemir, Aslihan; Judes, Gaëlle; Pajon, Amaury; Karsli-Ceppioglu, Seher; Penault-Llorca, Frédérique; Boiteux, Jean-Paul; Bignon, Yves-Jean; Guy, Laurent; Bernard-Gallon, Dominique

2015-02-01

With 13 million new cases worldwide every year, prostate cancer is as a very real public health concern. Prostate cancer is common in over-50s men and the sixth-leading cause of cancer-related death in men worldwide. Like all cancers, prostate cancer is multifactorial - there are non-modifiable risk factors like heredity, ethnicity and geographic location, but also modifiable risk factors such as diet. Diet-cancer linkages have risen to prominence in the last few years, with accruing epidemiological data pointing to between-population incidence differentials in numerous cancers. Indeed, there are correlations between fat-rich diet and risk of hormone-dependent cancers like prostate cancer and breast cancer. Diet is a risk factor for prostate cancer, but certain micronutrients in specific diets are considered protective factors against prostate cancer. Examples include tomato lycopene, green tea epigallocatechin gallate, and soy phytoestrogens. These micronutrients are thought to exert cancer-protective effects via anti-oxidant pathways and inhibition of cell proliferation. Here, we focus in on the effects of phytoestrogens, and chiefly genistein and daidzein, which are the best-researched to date. Soy phytoestrogens are nonsteroid molecules whose structural similarity lends them the ability to mimic the effects of 17ß-estradiol. On top of anti-oxidant effects, there is evidence that soy phytoestrogens can modulate the epigenetic modifications found in prostate cancer. We also studied the impact of phytoestrogens on epigenetic modifications in prostate cancer, with special focus on DNA methylation, miRNA-mediated regulation and histone modifications. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

KAP1 Is a Host Restriction Factor That Promotes Human Adenovirus E1B-55K SUMO Modification

DEFF Research Database (Denmark)

Bürck, Carolin; Mund, Andreas; Berscheminski, Julia

2016-01-01

Once transported to the replication sites, HAdVs need to assure decondensation and transcriptional activation of their viral genomes to synthesize viral proteins and initiate steps to reprogram the host cell for viral replication. These early stages during adenoviral infection are poorly characte......Once transported to the replication sites, HAdVs need to assure decondensation and transcriptional activation of their viral genomes to synthesize viral proteins and initiate steps to reprogram the host cell for viral replication. These early stages during adenoviral infection are poorly...... characterized, but represent a decisive moment in establishing a productive infection. Here, we identify a novel host viral restriction factor, KAP1. This heterochromatin associated transcription factor regulates the dynamic organization of host chromatin structure via its ability to influence epigenetic marks...

Journal of Biosciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Permanent link: https://www.ias.ac.in/article/fulltext/jbsc/041/04/0759-0786. Keywords. Epigenetics; genomic imprinting; heterochromatin; HP1; KRAB-ZFP. Abstract. Twenty five years ago it was proposed that conserved components of constitutive heterochromatin assemble heterochromatinlikecomplexes in euchromatin ...

Epigenetics in adipose tissue, obesity, weight loss, and diabetes.

Science.gov (United States)

Martínez, J Alfredo; Milagro, Fermín I; Claycombe, Kate J; Schalinske, Kevin L

2014-01-01

Given the role that diet and other environmental factors play in the development of obesity and type 2 diabetes, the implication of different epigenetic processes is being investigated. Although it is well known that external factors can cause cell type-dependent epigenetic changes, including DNA methylation, histone tail modifications, and chromatin remodeling, the regulation of these processes, the magnitude of the changes and the cell types in which they occur, the individuals more predisposed, and the more crucial stages of life remain to be elucidated. There is evidence that obese and diabetic people have a pattern of epigenetic marks different from nonobese and nondiabetic individuals. The main long-term goals in this field are the identification and understanding of the role of epigenetic marks that could be used as early predictors of metabolic risk and the development of drugs or diet-related treatments able to delay these epigenetic changes and even reverse them. But weight gain and insulin resistance/diabetes are influenced not only by epigenetic factors; different epigenetic biomarkers have also been identified as early predictors of weight loss and the maintenance of body weight after weight loss. The characterization of all the factors that are able to modify the epigenetic signatures and the determination of their real importance are hindered by the following factors: the magnitude of change produced by dietary and environmental factors is small and cumulative; there are great differences among cell types; and there are many factors involved, including age, with multiple interactions between them.

Repeat Composition of CenH3-chromatin and H3K9me2-marked heterochromatin in Sugar Beet (Beta vulgaris)

Czech Academy of Sciences Publication Activity Database

Kowar, T.; Zakrzewski, F.; Macas, Jiří; Koblížková, Andrea; Viehoever, P.; Weisshaar, B.; Schmidt, T.

2016-01-01

Roč. 16, č. 120 (2016) ISSN 1471-2229 R&D Projects: GA ČR GBP501/12/G090 Institutional support: RVO:60077344 Keywords : Centromere * CenH3 * H3K9me2 * Heterochromatin Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.964, year: 2016

Epigenetics and Therapeutic Targets Mediating Neuroprotection

Science.gov (United States)

Qureshi, Irfan A.; Mehler, Mark F.

2015-01-01

The rapidly evolving science of epigenetics is transforming our understanding of the nervous system in health and disease and holds great promise for the development of novel diagnostic and therapeutic approaches targeting neurological diseases. Increasing evidence suggests that epigenetic factors and mechanisms serve as important mediators of the pathogenic processes that lead to irrevocable neural injury and of countervailing homeostatic and regenerative responses. Epigenetics is, therefore, of considerable translational significance to the field of neuroprotection. In this brief review, we provide an overview of epigenetic mechanisms and highlight the emerging roles played by epigenetic processes in neural cell dysfunction and death and in resultant neuroprotective responses. PMID:26236020

Epigenetic Alterations in Alzheimer’s Disease

Science.gov (United States)

Sanchez-Mut, Jose V.; Gräff, Johannes

2015-01-01

Alzheimer’s disease (AD) is the major cause of dementia in Western societies. It progresses asymptomatically during decades before being belatedly diagnosed when therapeutic strategies have become unviable. Although several genetic alterations have been associated with AD, the vast majority of AD cases do not show strong genetic underpinnings and are thus considered a consequence of non-genetic factors. Epigenetic mechanisms allow for the integration of long-lasting non-genetic inputs on specific genetic backgrounds, and recently, a growing number of epigenetic alterations in AD have been described. For instance, an accumulation of dysregulated epigenetic mechanisms in aging, the predominant risk factor of AD, might facilitate the onset of the disease. Likewise, mutations in several enzymes of the epigenetic machinery have been associated with neurodegenerative processes that are altered in AD such as impaired learning and memory formation. Genome-wide and locus-specific epigenetic alterations have also been reported, and several epigenetically dysregulated genes validated by independent groups. From these studies, a picture emerges of AD as being associated with DNA hypermethylation and histone deacetylation, suggesting a general repressed chromatin state and epigenetically reduced plasticity in AD. Here we review these recent findings and discuss several technical and methodological considerations that are imperative for their correct interpretation. We also pay particular focus on potential implementations and theoretical frameworks that we expect will help to better direct future studies aimed to unravel the epigenetic participation in AD. PMID:26734709

Epigenetics of obesity: beyond the genome sequence.

Science.gov (United States)

Cordero, Paul; Li, Jiawei; Oben, Jude A

2015-07-01

After the study of the gene code as a trigger for obesity, epigenetic code has appeared as a novel tool in the diagnosis, prognosis and treatment of obesity, and its related comorbidities. This review summarizes the status of the epigenetic field associated with obesity, and the current epigenetic-based approaches for obesity treatment. Thanks to technical advances, novel and key obesity-associated polymorphisms have been described by genome-wide association studies, but there are limitations with their predictive power. Epigenetics is also studied for disease association, which involves decoding of the genome information, transcriptional status and later phenotypes. Obesity could be induced during adult life by feeding and other environmental factors, and there is a strong association between obesity features and specific epigenetic patterns. These patterns could be established during early life stages, and programme the risk of obesity and its comorbidities during adult life. Furthermore, recent studies have shown that DNA methylation profile could be applied as biomarkers of diet-induced weight loss treatment. High-throughput technologies, recently implemented for commercial genetic test panels, could soon lead to the creation of epigenetic test panels for obesity. Nonetheless, epigenetics is a modifiable risk factor, and different dietary patterns or environmental insights during distinct stages of life could lead to rewriting of the epigenetic profile.

The Emerging Role of Epigenetics in Inflammation and Immunometabolism

DEFF Research Database (Denmark)

Raghuraman, Sukanya; Donkin, Ida; Versteyhe, Soetkin

2016-01-01

Recent research developments have shed light on the risk factors contributing to metabolic complications, implicating both genetic and environmental factors, potentially integrated by epigenetic mechanisms. Distinct epigenetic changes in immune cells are frequently observed in obesity and type 2 ...... we provide an overview of the epigenetic mechanisms influencing immune cell phenotype and function, summarize current knowledge about epigenetic changes affecting immune functions in the context of metabolic diseases, and discuss the therapeutic options currently available to counteract...

Epigenetics of Autism Spectrum Disorder.

Science.gov (United States)

Siu, Michelle T; Weksberg, Rosanna

2017-01-01

Autism spectrum disorder (ASD), one of the most common childhood neurodevelopmental disorders (NDDs), is diagnosed in 1 of every 68 children. ASD is incredibly heterogeneous both clinically and aetiologically. The etiopathogenesis of ASD is known to be complex, including genetic, environmental and epigenetic factors. Normal epigenetic marks modifiable by both genetics and environmental exposures can result in epigenetic alterations that disrupt the regulation of gene expression, negatively impacting biological pathways important for brain development. In this chapter we aim to summarize some of the important literature that supports a role for epigenetics in the underlying molecular mechanism of ASD. We provide evidence from work in genetics, from environmental exposures and finally from more recent studies aimed at directly determining ASD-specific epigenetic patterns, focusing mainly on DNA methylation (DNAm). Finally, we briefly discuss some of the implications of current research on potential epigenetic targets for therapeutics and novel avenues for future work.

[Folates and fetal programming: role of epigenetics and epigenomics].

Science.gov (United States)

Guéant, Jean-Louis; Daval, Jean-Luc; Vert, Paul; Nicolas, Jean-Pierre

2012-12-01

Folates are needed for synthesis of methionine, the precursor of S-adenosyl methionine (SAM). They play therefore a key role in nutrition and epigenomics by fluxing monocarbons towards synthesis or methylation of DNA and RNA, and methylation of gene transregulators, respectively. The deficiency produces intrauterine growth retardation and birth dejects. Folate deficiency deregulates epigenomic mechanisms related to fetal programming through decreased cellular availability of SAM. Epigenetic mechanisms of folate deficiency are illustrated by inheritance of coat colour of agouti mice model and altered expression of Igf2/H19 imprinting genes. Dietary exposure to fumonisin FB1 acts synergistically with folate deficiency on alterations of heterochromatin assembly. Deficiency in folate and vitamin B12 produces impaired fatty acid oxidation in liver and heart through imbalanced methylation and acetylation of PGC1-alpha and decreased expression of SIRT1, and long-lasting cognitive disabilities through impaired hippocampal cell proliferation, differentiation and plasticity and atrophy of hippocampal CA1. Deciphering these mechanisms will help understand the discordances between experimental models and population studies on folate supplementation.

Eating Disorders and Epigenetics.

Science.gov (United States)

Thaler, Lea; Steiger, Howard

2017-01-01

Eating disorders (EDs) are characterized by intense preoccupation with shape and weight and maladaptive eating practices. The complex of symptoms that characterize EDs often arise through the activation of latent genetic potentials by environmental exposures, and epigenetic mechanisms are believed to link environmental exposures to gene expression. This chapter provides an overview of genetic factors acting in the etiology of EDs. It then provides a background to the hypothesis that epigenetic mechanisms link stresses such as obstetric complications and childhood abuse as well as effects of malnutrition to eating disorders (EDs). The chapter then summarizes the emerging body of literature on epigenetics and EDs-mainly studies on DNA methylation in samples of anorexia and bulimia. The available evidence base suggests that an epigenetically informed perspective contributes in valuable ways to the understanding of why people develop EDs.

Testicular cancer from diagnosis to epigenetic factors

Science.gov (United States)

Boccellino, Mariarosaria; Vanacore, Daniela; Zappavigna, Silvia; Cavaliere, Carla; Rossetti, Sabrina; D’Aniello, Carmine; Chieffi, Paolo; Amler, Evzen; Buonerba, Carlo; Di Lorenzo, Giuseppe; Di Franco, Rossella; Izzo, Alessandro; Piscitelli, Raffaele; Iovane, Gelsomina; Muto, Paolo; Botti, Gerardo; Perdonà, Sisto; Caraglia, Michele; Facchini, Gaetano

2017-01-01

Testicular cancer (TC) is one of the most common neoplasms that occurs in male and includes germ cell tumors (GCT), sex cord-gonadal stromal tumors and secondary testicular tumors. Diagnosis of TC involves the evaluation of serum tumor markers alpha-fetoprotein, human chorionic gonadotropin and lactate dehydrogenase, but clinically several types of immunohistochemical markers are more useful and more sensitive in GCT, but not in teratoma. These new biomarkers are genes expressed in primordial germ cells/gonocytes and embryonic pluripotency-related cells but not in normal adult germ cells and they include PLAP, OCT3/4 (POU5F1), NANOG, SOX2, REX1, AP-2γ (TFAP2C) and LIN28. Gene expression in GCT is regulated, at least in part, by DNA and histone modifications, and the epigenetic profile of these tumours is characterised by genome-wide demethylation. There are different epigenetic modifications in TG-subtypes that reflect the normal developmental switch in primordial germ cells from an under- to normally methylated genome. The main purpose of this review is to illustrate the findings of recent investigations in the classification of male genital organs, the discoveries in the use of prognostic and diagnostic markers and the epigenetic aberrations mainly affecting the patterns of DNA methylation/histone modifications of genes (especially tumor suppressors) and microRNAs (miRNAs). PMID:29262668

Epigenetics in Adipose Tissue, Obesity, Weight Loss, and Diabetes12

Science.gov (United States)

Martínez, J. Alfredo; Milagro, Fermín I.; Claycombe, Kate J.; Schalinske, Kevin L.

2014-01-01

Given the role that diet and other environmental factors play in the development of obesity and type 2 diabetes, the implication of different epigenetic processes is being investigated. Although it is well known that external factors can cause cell type-dependent epigenetic changes, including DNA methylation, histone tail modifications, and chromatin remodeling, the regulation of these processes, the magnitude of the changes and the cell types in which they occur, the individuals more predisposed, and the more crucial stages of life remain to be elucidated. There is evidence that obese and diabetic people have a pattern of epigenetic marks different from nonobese and nondiabetic individuals. The main long-term goals in this field are the identification and understanding of the role of epigenetic marks that could be used as early predictors of metabolic risk and the development of drugs or diet-related treatments able to delay these epigenetic changes and even reverse them. But weight gain and insulin resistance/diabetes are influenced not only by epigenetic factors; different epigenetic biomarkers have also been identified as early predictors of weight loss and the maintenance of body weight after weight loss. The characterization of all the factors that are able to modify the epigenetic signatures and the determination of their real importance are hindered by the following factors: the magnitude of change produced by dietary and environmental factors is small and cumulative; there are great differences among cell types; and there are many factors involved, including age, with multiple interactions between them. PMID:24425725

Molecular structures of centromeric heterochromatin and karyotypic evolution in the Siamese crocodile (Crocodylus siamensis) (Crocodylidae, Crocodylia).

Science.gov (United States)

Kawagoshi, Taiki; Nishida, Chizuko; Ota, Hidetoshi; Kumazawa, Yoshinori; Endo, Hideki; Matsuda, Yoichi

2008-01-01

Crocodilians have several unique karyotypic features, such as small diploid chromosome numbers (30-42) and the absence of dot-shaped microchromosomes. Of the extant crocodilian species, the Siamese crocodile (Crocodylus siamensis) has no more than 2n = 30, comprising mostly bi-armed chromosomes with large centromeric heterochromatin blocks. To investigate the molecular structures of C-heterochromatin and genomic compartmentalization in the karyotype, characterized by the disappearance of tiny microchromosomes and reduced chromosome number, we performed molecular cloning of centromeric repetitive sequences and chromosome mapping of the 18S-28S rDNA and telomeric (TTAGGG)( n ) sequences. The centromeric heterochromatin was composed mainly of two repetitive sequence families whose characteristics were quite different. Two types of GC-rich CSI-HindIII family sequences, the 305 bp CSI-HindIII-S (G+C content, 61.3%) and 424 bp CSI-HindIII-M (63.1%), were localized to the intensely PI-stained centric regions of all chromosomes, except for chromosome 2 with PI-negative heterochromatin. The 94 bp CSI-DraI (G+C content, 48.9%) was tandem-arrayed satellite DNA and localized to chromosome 2 and four pairs of small-sized chromosomes. The chromosomal size-dependent genomic compartmentalization that is supposedly unique to the Archosauromorpha was probably lost in the crocodilian lineage with the disappearance of microchromosomes followed by the homogenization of centromeric repetitive sequences between chromosomes, except for chromosome 2.

[Epigenetics' implication in autism spectrum disorders: A review].

Science.gov (United States)

Hamza, M; Halayem, S; Mrad, R; Bourgou, S; Charfi, F; Belhadj, A

2017-08-01

The etiology of autism spectrum disorders (ASD) is complex and multifactorial, and the roles of genetic and environmental factors in its emergence have been well documented. Current research tends to indicate that these two factors act in a synergistic manner. The processes underlying this interaction are still poorly known, but epigenetic modifications could be the mediator in the gene/environment interface. The epigenetic mechanisms have been implicated in susceptibility to stress and also in the pathogenesis of psychiatric disorders including depression and schizophrenia. Currently, several studies focus on the consideration of the etiological role of epigenetic regulation in ASD. The object of this review is to present a summary of current knowledge of an epigenetic hypothesis in ASD, outlining the recent findings in this field. Using Pubmed, we did a systematic review of the literature researching words such as: autism spectrum disorders, epigenetics, DNA methylation and histone modification. Epigenetic refers to the molecular process modulating gene expression without changes in the DNA sequence. The most studied epigenetic mechanisms are those that alter the chromatin structure including DNA methylation of cytosine residues in CpG dinucleotides and post-translational histone modifications. In ASD several arguments support the epigenetic hypothesis. In fact, there is a frequent association between ASD and genetic diseases whose epigenetic etiologies are recognized. A disturbance in the expression of genes involved in the epigenetic regulation has also been described in this disorder. Some studies have demonstrated changes in the DNA methylation of several autism candidate genes including the gene encoding the oxytocin receptor (OXTR), the RELN and the SHANK3 genes. Beyond the analysis of candidate genes, recent epigenome-wide association studies have investigated the methylation level of several other genes and showed hypomethylation of the whole DNA in brain

The Emerging Role of Epigenetics in Inflammation and Immunometabolism.

Science.gov (United States)

Raghuraman, Sukanya; Donkin, Ida; Versteyhe, Soetkin; Barrès, Romain; Simar, David

2016-11-01

Recent research developments have shed light on the risk factors contributing to metabolic complications, implicating both genetic and environmental factors, potentially integrated by epigenetic mechanisms. Distinct epigenetic changes in immune cells are frequently observed in obesity and type 2 diabetes mellitus, and these are associated with alterations in the phenotype, function, and trafficking patterns of these cells. The first step in the development of effective therapeutic strategies is the identification of distinct epigenetic signatures associated with metabolic disorders. In this review we provide an overview of the epigenetic mechanisms influencing immune cell phenotype and function, summarize current knowledge about epigenetic changes affecting immune functions in the context of metabolic diseases, and discuss the therapeutic options currently available to counteract epigenetically driven metabolic complications. Copyright © 2016 Elsevier Ltd. All rights reserved.

A spherical harmonics intensity model for 3D segmentation and 3D shape analysis of heterochromatin foci.

Science.gov (United States)

Eck, Simon; Wörz, Stefan; Müller-Ott, Katharina; Hahn, Matthias; Biesdorf, Andreas; Schotta, Gunnar; Rippe, Karsten; Rohr, Karl

2016-08-01

The genome is partitioned into regions of euchromatin and heterochromatin. The organization of heterochromatin is important for the regulation of cellular processes such as chromosome segregation and gene silencing, and their misregulation is linked to cancer and other diseases. We present a model-based approach for automatic 3D segmentation and 3D shape analysis of heterochromatin foci from 3D confocal light microscopy images. Our approach employs a novel 3D intensity model based on spherical harmonics, which analytically describes the shape and intensities of the foci. The model parameters are determined by fitting the model to the image intensities using least-squares minimization. To characterize the 3D shape of the foci, we exploit the computed spherical harmonics coefficients and determine a shape descriptor. We applied our approach to 3D synthetic image data as well as real 3D static and real 3D time-lapse microscopy images, and compared the performance with that of previous approaches. It turned out that our approach yields accurate 3D segmentation results and performs better than previous approaches. We also show that our approach can be used for quantifying 3D shape differences of heterochromatin foci. Copyright © 2016 Elsevier B.V. All rights reserved.

Epigenetic interplay between mouse endogenous retroviruses and host genes.

Science.gov (United States)

Rebollo, Rita; Miceli-Royer, Katharine; Zhang, Ying; Farivar, Sharareh; Gagnier, Liane; Mager, Dixie L

2012-10-03

Transposable elements are often the targets of repressive epigenetic modifications such as DNA methylation that, in theory, have the potential to spread toward nearby genes and induce epigenetic silencing. To better understand the role of DNA methylation in the relationship between transposable elements and genes, we assessed the methylation state of mouse endogenous retroviruses (ERVs) located near genes. We found that ERVs of the ETn/MusD family show decreased DNA methylation when near transcription start sites in tissues where the nearby gene is expressed. ERVs belonging to the IAP family, however, are generally heavily methylated, regardless of the genomic environment and the tissue studied. Furthermore, we found full-length ETn and IAP copies that display differential DNA methylation between their two long terminal repeats (LTRs), suggesting that the environment surrounding gene promoters can prevent methylation of the nearby LTR. Spreading from methylated ERV copies to nearby genes was rarely observed, with the regions between the ERVs and genes apparently acting as a boundary, enriched in H3K4me3 and CTCF, which possibly protects the unmethylated gene promoter. Furthermore, the flanking regions of unmethylated ERV copies harbor H3K4me3, consistent with spreading of euchromatin from the host gene toward ERV insertions. We have shown that spreading of DNA methylation from ERV copies toward active gene promoters is rare. We provide evidence that genes can be protected from ERV-induced heterochromatin spreading by either blocking the invasion of repressive marks or by spreading euchromatin toward the ERV copy.

A network of epigenetic modifiers and DNA repair genes controls tissue-specific copy number alteration preference.

Science.gov (United States)

Cramer, Dina; Serrano, Luis; Schaefer, Martin H

2016-11-10

Copy number alterations (CNAs) in cancer patients show a large variability in their number, length and position, but the sources of this variability are not known. CNA number and length are linked to patient survival, suggesting clinical relevance. We have identified genes that tend to be mutated in samples that have few or many CNAs, which we term CONIM genes (COpy Number Instability Modulators). CONIM proteins cluster into a densely connected subnetwork of physical interactions and many of them are epigenetic modifiers. Therefore, we investigated how the epigenome of the tissue-of-origin influences the position of CNA breakpoints and the properties of the resulting CNAs. We found that the presence of heterochromatin in the tissue-of-origin contributes to the recurrence and length of CNAs in the respective cancer type.

Analysis of the human HP1 interactome reveals novel binding partners

DEFF Research Database (Denmark)

Rosnoblet, Claire; Vandamme, Julien; Völkel, Pamela

2011-01-01

Heterochromatin protein 1 (HP1) has first been described in Drosophila as an essential component of constitutive heterochromatin required for stable epigenetic gene silencing. Less is known about the three mammalian HP1 isotypes CBX1, CBX3 and CBX5. Here, we applied a tandem affinity purification...

Trichostatin A treatment of cloned mouse embryos improves constitutive heterochromatin remodeling as well as developmental potential to term

Directory of Open Access Journals (Sweden)

Brochard Vincent

2009-02-01

Full Text Available Abstract Background Genome reprogramming in early mouse embryos is associated with nuclear reorganization and particular features such as the peculiar distribution of centromeric and pericentric heterochromatin during the first developmental stage. This zygote-specific heterochromatin organization could be observed both in maternal and paternal pronuclei after natural fertilization as well as in embryonic stem (ES cell nuclei after nuclear transfer suggesting that this particular type of nuclear organization was essential for embryonic reprogramming and subsequent development. Results Here, we show that remodeling into a zygotic-like organization also occurs after somatic cell nuclear transfer (SCNT, supporting the hypothesis that reorganization of constitutive heterochromatin occurs regardless of the source and differentiation state of the starting material. However, abnormal nuclear remodeling was frequently observed after SCNT, in association with low developmental efficiency. When transient treatment with the histone deacetylase inhibitor trichostatin A (TSA was tested, we observed improved nuclear remodeling in 1-cell SCNT embryos that correlated with improved rates of embryonic development at subsequent stages. Conclusion Together, the results suggest that proper organization of constitutive heterochromatin in early embryos is involved in the initial developmental steps and might have long term consequences, especially in cloning procedures.

Epigenetic diet: impact on the epigenome and cancer

Science.gov (United States)

Hardy, Tabitha M; Tollefsbol, Trygve O

2011-01-01

A number of bioactive dietary components are of particular interest in the field of epigenetics. Many of these compounds display anticancer properties and may play a role in cancer prevention. Numerous studies suggest that a number of nutritional compounds have epigenetic targets in cancer cells. Importantly, emerging evidence strongly suggests that consumption of dietary agents can alter normal epigenetic states as well as reverse abnormal gene activation or silencing. Epigenetic modifications induced by bioactive dietary compounds are thought to be beneficial. Substantial evidence is mounting proclaiming that commonly consumed bioactive dietary factors act to modify the epigenome and may be incorporated into an ‘epigenetic diet’. Bioactive nutritional components of an epigenetic diet may be incorporated into one’s regular dietary regimen and used therapeutically for medicinal or chemopreventive purposes. This article will primarily focus on dietary factors that have been demonstrated to influence the epigenome and that may be used in conjunction with other cancer prevention and chemotherapeutic therapies. PMID:22022340

Individuality and epigenetics in obesity.

Science.gov (United States)

Campión, J; Milagro, F I; Martínez, J A

2009-07-01

Excessive weight gain arises from the interactions among environmental factors, genetic predisposition and the individual behavior. However, it is becoming evident that interindividual differences in obesity susceptibility depend also on epigenetic factors. Epigenetics studies the heritable changes in gene expression that do not involve changes to the underlying DNA sequence. These processes include DNA methylation, covalent histone modifications, chromatin folding and, more recently described, the regulatory action of miRNAs and polycomb group complexes. In this review, we focus on experimental evidences concerning dietary factors influencing obesity development by epigenetic mechanisms, reporting treatment doses and durations. Moreover, we present a bioinformatic analysis of promoter regions for the search of future epigenetic biomarkers of obesity, including methylation pattern analyses of several obesity-related genes (epiobesigenes), such as FGF2, PTEN, CDKN1A and ESR1, implicated in adipogenesis, SOCS1/SOCS3, in inflammation, and COX7A1 LPL, CAV1, and IGFBP3, in intermediate metabolism and insulin signalling. The identification of those individuals that at an early age could present changes in the methylation profiles of specific genes could help to predict their susceptibility to later develop obesity, which may allow to prevent and follow-up its progress, as well as to research and develop newer therapeutic approaches.

Introduction to the Special Section on Epigenetics.

Science.gov (United States)

Lester, Barry M; Conradt, Elisabeth; Marsit, Carmen

2016-01-01

Epigenetics provides the opportunity to revolutionize our understanding of the role of genetics and the environment in explaining human behavior, although the use of epigenetics to study human behavior is just beginning. In this introduction, the authors present the basics of epigenetics in a way that is designed to make this exciting field accessible to a wide readership. The authors describe the history of human behavioral epigenetic research in the context of other disciplines and graphically illustrate the burgeoning of research in the application of epigenetic methods and principles to the study of human behavior. The role of epigenetics in normal embryonic development and the influence of biological and environmental factors altering behavior through epigenetic mechanisms and developmental programming are discussed. Some basic approaches to the study of epigenetics are reviewed. The authors conclude with a discussion of challenges and opportunities, including intervention, as the field of human behavioral epigenetics continue to grow. © 2016 The Authors. Child Development © 2016 Society for Research in Child Development, Inc.

Molecular characterization of constitutive heterochromatin in three species of Trypoxylon (Hymenoptera, Crabronidae, Trypoxylini by CMA3/DAPI staining

Directory of Open Access Journals (Sweden)

Rodolpho Menezes

2011-07-01

Full Text Available Previous cytogenetic analyses in Trypoxylon Latreille, 1796 have been basically restricted to C-banding. In the present study, base-specific CMA3 and DAPI fluorochrome staining were used to characterize the constitutive heterochromatin in three Trypoxylon species. The heterochromatin was GC-rich in all the species studied; however, in Trypoxylon nitidum F. Smith, 1856 the molecular composition of the heterochromatin was different among chromosome pairs. Conversely, the euchromatin was AT-rich in the three species. These results suggest high conservatism in the euchromatic regions as opposed to the heterochromatic regions that have a high rate of changes. In this study, we report the karyotype of Trypoxylon rugifrons F. Smith, 1873 which has the lowest chromosome number in the genus and other characteristics of the likely ancestral Trypoxylon karyotype.

Cooperative DNA and histone binding by Uhrf2 links the two major repressive epigenetic pathways

Science.gov (United States)

Pichler, Garwin; Wolf, Patricia; Schmidt, Christine S; Meilinger, Daniela; Schneider, Katrin; Frauer, Carina; Fellinger, Karin; Rottach, Andrea; Leonhardt, Heinrich

2011-01-01

Gene expression is regulated by DNA as well as histone modifications but the crosstalk and mechanistic link between these epigenetic signals are still poorly understood. Here we investigate the multi-domain protein Uhrf2 that is similar to Uhrf1, an essential cofactor of maintenance DNA methylation. Binding assays demonstrate a cooperative interplay of Uhrf2 domains that induces preference for hemimethylated DNA, the substrate of maintenance methylation, and enhances binding to H3K9me3 heterochromatin marks. FRAP analyses revealed that localization and binding dynamics of Uhrf2 in vivo require an intact tandem Tudor domain and depend on H3K9 trimethylation but not on DNA methylation. Besides the cooperative DNA and histone binding that is characteristic for Uhrf2, we also found an opposite expression pattern of uhrf1 and uhrf2 during differentiation. While uhrf1 is mainly expressed in pluripotent stem cells, uhrf2 is upregulated during differentiation and highly expressed in differentiated mouse tissues. Ectopic expression of Uhrf2 in uhrf1−/− embryonic stem cells did not restore DNA methylation at major satellites indicating functional differences. We propose that the cooperative interplay of Uhrf2 domains may contribute to a tighter epigenetic control of gene expression in differentiated cells. PMID:21598301

Anxiety and Epigenetics.

Science.gov (United States)

Bartlett, Andrew A; Singh, Rumani; Hunter, Richard G

2017-01-01

Anxiety disorders are highly prevalent psychiatric disorders often comorbid with depression and substance abuse. Twin studies have shown that anxiety disorders are moderately heritable. Yet, genome-wide association studies (GWASs) have failed to identify gene(s) significantly associated with diagnosis suggesting a strong role for environmental factors and the epigenome. A number of anxiety disorder subtypes are considered "stress related." A large focus of research has been on the epigenetic and anxiety-like behavioral consequences of stress. Animal models of anxiety-related disorders have provided strong evidence for the role of stress on the epigenetic control of the hypothalamic-pituitary-adrenal (HPA) axis and of stress-responsive brain regions. Neuroepigenetics may continue to explain individual variation in susceptibility to environmental perturbations and consequently anxious behavior. Behavioral and pharmacological interventions aimed at targeting epigenetic marks associated with anxiety may prove fruitful in developing treatments.

Genetic and bioinformatic analysis of 41C and the 2R heterochromatin of Drosophila melanogaster: a window on the heterochromatin-euchromatin junction.

OpenAIRE

Myster, Steven H; Wang, Fei; Cavallo, Robert; Christian, Whitney; Bhotika, Seema; Anderson, Charles T; Peifer, Mark

2004-01-01

Genomic sequences provide powerful new tools in genetic analysis, making it possible to combine classical genetics with genomics to characterize the genes in a particular chromosome region. These approaches have been applied successfully to the euchromatin, but analysis of the heterochromatin has lagged somewhat behind. We describe a combined genetic and bioinformatics approach to the base of the right arm of the Drosophila melanogaster second chromosome, at the boundary between pericentric h...

EG-17SUV420-MEDIATED HETEROCHROMATIN CHANGES IN PEDIATRIC BRAIN CANCERS

Science.gov (United States)

Van Meter, Timothy E.; Terry, Jocelyn; Rockwell, Nathan; Goggin, Sarah; Nethala, Priya; Khan, Asadullah

2014-01-01

Silencing mechanisms play a role in genomic stability by maintaining condensed, non-active regions of the genome. SUV420 enzymes contain a SET domain conferring methyltransferase activity toward histones. The Histone H4 lysine 20 trimethylation (H4K20me3) mark maintained by SUV420H2 is associated with heterochromatin formation and gene silencing, whereas the dimethylated mark (H4K20me2) is associated with DNA repair. In studies of epigenetic factors in large patient cohorts with ependymoma, it was found that SUV420H2 expression was lost or diminished in patients with reciprocal increases in prognostic markers such as hTERT. To better understand the normal function of Suv4-20H1/H2 enzyme in neural progenitors, and pathological changes in cancers, a variety of differentiation paradigms were used. The NT2D1 neurally restricted cell line, and BGO1V and H9 human embryonic stem cells (ESCs), and differentiated progeny, were used alongside tumors to better understand enzyme targets and functional outcomes (e.g.,lineage, differentiation, regional chromatin modifications). Lineage stages were verified with stage-specific markers by immunofluorescence and qPCR. Suv4-20 H1 and H2 were present in ESCs and neural progenitors and decreased thereafter. RNAi knockdown of SUV420 enzymes led to decreased H4K20 methylation in cancer cells. DNA methylation microarrays and ChIP-PCR suggest 1) that SUV420 is not regulated by DNA methylation in ependymomas; 2) that active chromatin marks such as H3K4 dimethylation are enriched near the transcriptional start site in the SUV420H2 gene, and 3) that hTERT is hyper-methylated at specific CpG islands and histones in a tumor sub-group-specific manner. This data supports the hypothesis that Suv4-20H2 is highly active in progenitor cells and functionally lost in some brain cancers. These studies begin to elucidate coincident mechanisms of gene silencing active in neural progenitors that may be altered in a subset of pediatric brain cancers.

Amplification of a GC-rich heterochromatin in the freshwater fish Leporinus desmotes (Characiformes, Anostomidae

Directory of Open Access Journals (Sweden)

Vladimir Pavan Margarido

2000-09-01

Full Text Available This is the first description of the karyotype of Leporinus desmotes. The diploid female number was 2n = 54 meta- and submetacentric chromosomes. The nucleolar organizing regions (NORs were studied by silver nitrate staining and rDNA fluorescence in situ hybridization (FISH and were found to be located in the telomeric region of the long arm of the 9th pair. C-banding revealed centromeric and telomeric heterochromatin segments in most chromosomes. Intercalar blocks of heterochromatin were observed in the long arm of six chromosome pairs. Besides a NOR-adjacent heterochromatin, all of the intercalar heterochromatic segments were brightly fluorescent by mithramycin staining. These data suggest that a unique amplification of a primordial GC-rich heterochromatin, probably NOR-associated, may have taken place in the karyotype diversification of this Leporinus species.Esta é a primeira descrição do cariótipo de Leporinus desmotes fêmea. O número diplóide encontrado foi 2n = 54 cromossomos meta- e submetacêntricos. As regiões organizadoras de nucléolos (NORs foram estudadas através da impregnação pela prata e por hibridização in situ com sondas de DNAr (FISH, e foram localizadas na região telomérica do braço longo do 9º par. Heterocromatinas centromérica e telomérica foram reveladas pelo bandamento C na maioria dos cromossomos. Adicionalmente, grande quantidade de heterocromatina intercalar ou subtelomérica foi também observada. Diferenciação composicional na maior parte da heterocromatina identificada em L. desmotes pode ser inferida através da coloração pela mitramicina, caracterizando um caso peculiar de amplificação de segmentos heterocromáticos ricos em bases GC neste grupo de peixes.

Analysis of epigenetic factors in mouse embryonic neural stem cells exposed to hyperglycemia.

Directory of Open Access Journals (Sweden)

Sukanya Shyamasundar

Full Text Available BACKGROUND: Maternal diabetes alters gene expression leading to neural tube defects (NTDs in the developing brain. The mechanistic pathways that deregulate the gene expression remain unknown. It is hypothesized that exposure of neural stem cells (NSCs to high glucose/hyperglycemia results in activation of epigenetic mechanisms which alter gene expression and cell fate during brain development. METHODS AND FINDINGS: NSCs were isolated from normal pregnancy and streptozotocin induced-diabetic pregnancy and cultured in physiological glucose. In order to examine hyperglycemia induced epigenetic changes in NSCs, chromatin reorganization, global histone status at lysine 9 residue of histone H3 (acetylation and trimethylation and global DNA methylation were examined and found to be altered by hyperglycemia. In NSCs, hyperglycemia increased the expression of Dcx (Doublecortin and Pafah1b1 (Platelet activating factor acetyl hydrolase, isoform 1b, subunit 1 proteins concomitant with decreased expression of four microRNAs (mmu-miR-200a, mmu-miR-200b, mmu-miR-466a-3p and mmu-miR-466 d-3p predicted to target these genes. Knockdown of specific microRNAs in NSCs resulted in increased expression of Dcx and Pafah1b1 proteins confirming target prediction and altered NSC fate by increasing the expression of neuronal and glial lineage markers. CONCLUSION/INTERPRETATION: This study revealed that hyperglycemia alters the epigenetic mechanisms in NSCs, resulting in altered expression of some development control genes which may form the basis for the NTDs. Since epigenetic changes are reversible, they may be valuable therapeutic targets in order to improve fetal outcomes in diabetic pregnancy.

Epigenetic and epistatic interactions between serotonin transporter and brain-derived neurotrophic factor genetic polymorphism: insights in depression.

Science.gov (United States)

Ignácio, Z M; Réus, G Z; Abelaira, H M; Quevedo, J

2014-09-05

Epidemiological studies have shown significant results in the interaction between the functions of brain-derived neurotrophic factor (BDNF) and 5-HT in mood disorders, such as major depressive disorder (MDD). The latest research has provided convincing evidence that gene transcription of these molecules is a target for epigenetic changes, triggered by stressful stimuli that starts in early childhood and continues throughout life, which are subsequently translated into structural and functional phenotypes culminating in depressive disorders. The short variants of 5-HTTLPR and BDNF-Met are seen as forms which are predisposed to epigenetic aberrations, which leads individuals to a susceptibility to environmental adversities, especially when subjected to stress in early life. Moreover, the polymorphic variants also feature epistatic interactions in directing the functional mechanisms elicited by stress and underlying the onset of depressive disorders. Also emphasized are works which show some mediators between stress and epigenetic changes of the 5-HTT and BDNF genes, such as the hypothalamic-pituitary-adrenal (HPA) axis and the cAMP response element-binding protein (CREB), which is a cellular transcription factor. Both the HPA axis and CREB are also involved in epistatic interactions between polymorphic variants of 5-HTTLPR and Val66Met. This review highlights some research studying changes in the epigenetic patterns intrinsic to genes of 5-HTT and BDNF, which are related to lifelong environmental adversities, which in turn increases the risks of developing MDD. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Derangement of a factor upstream of RARalpha triggers the repression of a pleiotropic epigenetic network.

Directory of Open Access Journals (Sweden)

Francesca Corlazzoli

Full Text Available Chromatin adapts and responds to extrinsic and intrinsic cues. We hypothesize that inheritable aberrant chromatin states in cancer and aging are caused by genetic/environmental factors. In previous studies we demonstrated that either genetic mutations, or loss, of retinoic acid receptor alpha (RARalpha, can impair the integration of the retinoic acid (RA signal at the chromatin of RA-responsive genes downstream of RARalpha, and can lead to aberrant repressive chromatin states marked by epigenetic modifications. In this study we tested whether the mere interference with the availability of RA signal at RARalpha, in cells with an otherwise functional RARalpha, can also induce epigenetic repression at RA-responsive genes downstream of RARalpha.To hamper the availability of RA at RARalpha in untransformed human mammary epithelial cells, we targeted the cellular RA-binding protein 2 (CRABP2, which transports RA from the cytoplasm onto the nuclear RARs. Stable ectopic expression of a CRABP2 mutant unable to enter the nucleus, as well as stable knock down of endogenous CRABP2, led to the coordinated transcriptional repression of a few RA-responsive genes downstream of RARalpha. The chromatin at these genes acquired an exacerbated repressed state, or state "of no return". This aberrant state is unresponsive to RA, and therefore differs from the physiologically repressed, yet "poised" state, which is responsive to RA. Consistent with development of homozygosis for epigenetically repressed loci, a significant proportion of cells with a defective CRABP2-mediated RA transport developed heritable phenotypes indicative of loss of function.Derangement/lack of a critical factor necessary for RARalpha function induces epigenetic repression of a RA-regulated gene network downstream of RARalpha, with major pleiotropic biological outcomes.

The epigenetic landscape of alcoholism.

Science.gov (United States)

Krishnan, Harish R; Sakharkar, Amul J; Teppen, Tara L; Berkel, Tiffani D M; Pandey, Subhash C

2014-01-01

Alcoholism is a complex psychiatric disorder that has a multifactorial etiology. Epigenetic mechanisms are uniquely capable of accounting for the multifactorial nature of the disease in that they are highly stable and are affected by environmental factors, including alcohol itself. Chromatin remodeling causes changes in gene expression in specific brain regions contributing to the endophenotypes of alcoholism such as tolerance and dependence. The epigenetic mechanisms that regulate changes in gene expression observed in addictive behaviors respond not only to alcohol exposure but also to comorbid psychopathology such as the presence of anxiety and stress. This review summarizes recent developments in epigenetic research that may play a role in alcoholism. We propose that pharmacologically manipulating epigenetic targets, as demonstrated in various preclinical models, hold great therapeutic potential in the treatment and prevention of alcoholism. © 2014 Elsevier Inc. All rights reserved.

Deacetylation of H4-K16Ac and heterochromatin assembly in senescence

Directory of Open Access Journals (Sweden)

Contrepois Kévin

2012-08-01

Full Text Available Abstract Background Cellular senescence is a stress response of mammalian cells leading to a durable arrest of cell proliferation that has been implicated in tumor suppression, wound healing, and aging. The proliferative arrest is mediated by transcriptional repression of genes essential for cell division by the retinoblastoma protein family. This repression is accompanied by varying degrees of heterochromatin assembly, but little is known regarding the molecular mechanisms involved. Results We found that both deacetylation of H4-K16Ac and expression of HMGA1/2 can contribute to DNA compaction during senescence. SIRT2, an NAD-dependent class III histone deacetylase, contributes to H4-K16Ac deacetylation and DNA compaction in human fibroblast cell lines that assemble striking senescence-associated heterochromatin foci (SAHFs. Decreased H4-K16Ac was observed in both replicative and oncogene-induced senescence of these cells. In contrast, this mechanism was inoperative in a fibroblast cell line that did not assemble extensive heterochromatin during senescence. Treatment of senescent cells with trichostatin A, a class I/II histone deacetylase inhibitor, also induced rapid and reversible decondensation of SAHFs. Inhibition of DNA compaction did not significantly affect the stability of the senescent state. Conclusions Variable DNA compaction observed during senescence is explained in part by cell-type specific regulation of H4 deacetylation and HMGA1/2 expression. Deacetylation of H4-K16Ac during senescence may explain reported decreases in this mark during mammalian aging and in cancer cells.

Epigenetic Markers of Renal Function in African Americans

Directory of Open Access Journals (Sweden)

Samantha M. Bomotti

2013-01-01

Full Text Available Chronic kidney disease (CKD is an increasing concern in the United States due to its rapidly rising prevalence, particularly among African Americans. Epigenetic DNA methylation markers are becoming important biomarkers of chronic diseases such as CKD. To better understand how these methylation markers play a role in kidney function, we measured 26,428 DNA methylation sites in 972 African Americans from the Genetic Epidemiology Network of Arteriopathy (GENOA study. We then evaluated (1 whether epigenetic markers are associated with estimated glomerular filtration rate (eGFR, (2 whether the significantly associated markers are also associated with traditional risk factors and/or novel biomarkers for eGFR, and (3 how much additional variation in eGFR is explained by epigenetic markers beyond established risk factors and biomarkers. The majority of methylation markers most significantly associated with eGFR (24 out of the top 30 appeared to function, at least in part, through pathways related to aging, inflammation, or cholesterol. However, six epigenetic markers were still able to significantly predict eGFR after adjustment for other risk factors. This work shows that epigenetic markers may offer valuable new insight into the complex pathophysiology of CKD in African Americans.

Epigenetics of Obesity.

Science.gov (United States)

Lopomo, A; Burgio, E; Migliore, L

2016-01-01

Obesity is a metabolic disease, which is becoming an epidemic health problem: it has been recently defined in terms of Global Pandemic. Over the years, the approaches through family, twins and adoption studies led to the identification of some causal genes in monogenic forms of obesity but the origins of the pandemic of obesity cannot be considered essentially due to genetic factors, because human genome is not likely to change in just a few years. Epigenetic studies have offered in recent years valuable tools for the understanding of the worldwide spread of the pandemic of obesity. The involvement of epigenetic modifications-DNA methylation, histone tails, and miRNAs modifications-in the development of obesity is more and more evident. In the epigenetic literature, there are evidences that the entire embryo-fetal and perinatal period of development plays a key role in the programming of all human organs and tissues. Therefore, the molecular mechanisms involved in the epigenetic programming require a new and general pathogenic paradigm, the Developmental Origins of Health and Disease theory, to explain the current epidemiological transition, that is, the worldwide increase of chronic, degenerative, and inflammatory diseases such as obesity, diabetes, cardiovascular diseases, neurodegenerative diseases, and cancer. Obesity and its related complications are more and more associated with environmental pollutants (obesogens), gut microbiota modifications and unbalanced food intake, which can induce, through epigenetic mechanisms, weight gain, and altered metabolic consequences. Copyright © 2016 Elsevier Inc. All rights reserved.

Epigenetic changes in solid and hematopoietic tumors.

Science.gov (United States)

Toyota, Minoru; Issa, Jean-Pierre J

2005-10-01

There are three connected molecular mechanisms of epigenetic cellular memory in mammalian cells: DNA methylation, histone modifications, and RNA interference. The first two have now been firmly linked to neoplastic transformation. Hypermethylation of CpG-rich promoters triggers local histone code modifications resulting in a cellular camouflage mechanism that sequesters gene promoters away from transcription factors and results in stable silencing. This normally restricted mechanism is ubiquitously used in cancer to silence hundreds of genes, among which some critically contribute to the neoplastic phenotype. Virtually every pathway important to cancer formation is affected by this process. Methylation profiling of human cancers reveals tissue-specific epigenetic signatures, as well as tumor-specific signatures, reflecting in particular the presence of epigenetic instability in a subset of cancers affected by the CpG island methylator phenotype. Generally, methylation patterns can be traced to a tissue-specific, proliferation-dependent accumulation of aberrant promoter methylation in aging tissues, a process that can be accelerated by chronic inflammation and less well-defined mechanisms including, possibly, diet and genetic predisposition. The epigenetic machinery can also be altered in cancer by specific lesions in epigenetic effector genes, or by aberrant recruitment of these genes by mutant transcription factors and coactivators. Epigenetic patterns are proving clinically useful in human oncology via risk assessment, early detection, and prognostic classification. Pharmacologic manipulation of these patterns-epigenetic therapy-is also poised to change the way we treat cancer in the clinic.

Epigenetic Alteration by DNA Promoter Hypermethylation of Genes Related to Transforming Growth Factor-β (TGF-β) Signaling in Cancer

Energy Technology Data Exchange (ETDEWEB)

Khin, Sann Sanda [Kobe University Graduate School of Medicine, Division of Diagnostic Molecular Pathology, Kobe 650-0017 (Japan); Pathology Research Unit, Department of Medical Research (Central Myanmar), Naypyitaw, Union of (Myanmar); Kitazawa, Riko [Kobe University Graduate School of Medicine, Division of Diagnostic Molecular Pathology, Kobe 650-0017 (Japan); Ehime University Graduate School of Medicine, Toon 791-0295, Ehime (Japan); Kondo, Takeshi; Idei, Yuka; Fujimoto, Masayo [Kobe University Graduate School of Medicine, Division of Diagnostic Molecular Pathology, Kobe 650-0017 (Japan); Haraguchi, Ryuma [Ehime University Graduate School of Medicine, Toon 791-0295, Ehime (Japan); Mori, Kiyoshi [Kobe University Graduate School of Medicine, Division of Diagnostic Molecular Pathology, Kobe 650-0017 (Japan); Kitazawa, Sohei, E-mail: kitazawa@m.ehime-u.ac.jp [Kobe University Graduate School of Medicine, Division of Diagnostic Molecular Pathology, Kobe 650-0017 (Japan); Ehime University Graduate School of Medicine, Toon 791-0295, Ehime (Japan)

2011-03-03

Epigenetic alterations in cancer, especially DNA methylation and histone modification, exert a significant effect on the deregulated expression of cancer-related genes and lay an epigenetic pathway to carcinogenesis and tumor progression. Global hypomethylation and local hypermethylation of CpG islands in the promoter region, which result in silencing tumor suppressor genes, constitute general and major epigenetic modification, the hallmark of the neoplastic epigenome. Additionally, methylation-induced gene silencing commonly affects a number of genes and increases with cancer progression. Indeed, cancers with a high degree of methylation (CpG island methylator phenotype/CIMP) do exist and represent a distinct subset of certain cancers including colorectal, bladder and kidney. On the other hand, signals from the microenvironment, especially those from transforming growth factor-β (TGF-β), induce targeted de novo epigenetic alterations of cancer-related genes. While TGF-β signaling has been implicated in two opposite roles in cancer, namely tumor suppression and tumor promotion, its deregulation is also partly induced by epigenetic alteration itself. Although the epigenetic pathway to carcinogenesis and cancer progression has such reciprocal complexity, the important issue is to identify genes or signaling pathways that are commonly silenced in various cancers in order to find early diagnostic and therapeutic targets. In this review, we focus on the epigenetic alteration by DNA methylation and its role in molecular modulations of the TGF-β signaling pathway that cause or underlie altered cancer-related gene expression in both phases of early carcinogenesis and late cancer progression.

Epigenetic Alteration by DNA Promoter Hypermethylation of Genes Related to Transforming Growth Factor-β (TGF-β) Signaling in Cancer

International Nuclear Information System (INIS)

Khin, Sann Sanda; Kitazawa, Riko; Kondo, Takeshi; Idei, Yuka; Fujimoto, Masayo; Haraguchi, Ryuma; Mori, Kiyoshi; Kitazawa, Sohei

2011-01-01

Epigenetic alterations in cancer, especially DNA methylation and histone modification, exert a significant effect on the deregulated expression of cancer-related genes and lay an epigenetic pathway to carcinogenesis and tumor progression. Global hypomethylation and local hypermethylation of CpG islands in the promoter region, which result in silencing tumor suppressor genes, constitute general and major epigenetic modification, the hallmark of the neoplastic epigenome. Additionally, methylation-induced gene silencing commonly affects a number of genes and increases with cancer progression. Indeed, cancers with a high degree of methylation (CpG island methylator phenotype/CIMP) do exist and represent a distinct subset of certain cancers including colorectal, bladder and kidney. On the other hand, signals from the microenvironment, especially those from transforming growth factor-β (TGF-β), induce targeted de novo epigenetic alterations of cancer-related genes. While TGF-β signaling has been implicated in two opposite roles in cancer, namely tumor suppression and tumor promotion, its deregulation is also partly induced by epigenetic alteration itself. Although the epigenetic pathway to carcinogenesis and cancer progression has such reciprocal complexity, the important issue is to identify genes or signaling pathways that are commonly silenced in various cancers in order to find early diagnostic and therapeutic targets. In this review, we focus on the epigenetic alteration by DNA methylation and its role in molecular modulations of the TGF-β signaling pathway that cause or underlie altered cancer-related gene expression in both phases of early carcinogenesis and late cancer progression

Transgenic Epigenetics: Using Transgenic Organisms to Examine Epigenetic Phenomena

Directory of Open Access Journals (Sweden)

Lori A. McEachern

2012-01-01

Full Text Available Non-model organisms are generally more difficult and/or time consuming to work with than model organisms. In addition, epigenetic analysis of model organisms is facilitated by well-established protocols, and commercially-available reagents and kits that may not be available for, or previously tested on, non-model organisms. Given the evolutionary conservation and widespread nature of many epigenetic mechanisms, a powerful method to analyze epigenetic phenomena from non-model organisms would be to use transgenic model organisms containing an epigenetic region of interest from the non-model. Interestingly, while transgenic Drosophila and mice have provided significant insight into the molecular mechanisms and evolutionary conservation of the epigenetic processes that target epigenetic control regions in other model organisms, this method has so far been under-exploited for non-model organism epigenetic analysis. This paper details several experiments that have examined the epigenetic processes of genomic imprinting and paramutation, by transferring an epigenetic control region from one model organism to another. These cross-species experiments demonstrate that valuable insight into both the molecular mechanisms and evolutionary conservation of epigenetic processes may be obtained via transgenic experiments, which can then be used to guide further investigations and experiments in the species of interest.

Epigenetic Modifications and Diabetic Retinopathy

Directory of Open Access Journals (Sweden)

Renu A. Kowluru

2013-01-01

Full Text Available Diabetic retinopathy remains one of the most debilitating chronic complications, but despite extensive research in the field, the exact mechanism(s responsible for how retina is damaged in diabetes remains ambiguous. Many metabolic pathways have been implicated in its development, and genes associated with these pathways are altered. Diabetic environment also facilitates epigenetics modifications, which can alter the gene expression without permanent changes in DNA sequence. The role of epigenetics in diabetic retinopathy is now an emerging area, and recent work has shown that genes encoding mitochondrial superoxide dismutase (Sod2 and matrix metalloproteinase-9 (MMP-9 are epigenetically modified, activates of epigenetic modification enzymes, histone lysine demethylase 1 (LSD1, and DNA methyltransferase are increased, and the micro RNAs responsible for regulating nuclear transcriptional factor and VEGF are upregulated. With the growing evidence of epigenetic modifications in diabetic retinopathy, better understanding of these modifications has potential to identify novel targets to inhibit this devastating disease. Fortunately, the inhibitors and mimics targeted towards histone modification, DNA methylation, and miRNAs are now being tried for cancer and other chronic diseases, and better understanding of the role of epigenetics in diabetic retinopathy will open the door for their possible use in combating this blinding disease.

Epigenetics in adipose tissue, obesity, weight loss and diabetes

Science.gov (United States)

Given the role that the diet and other environmental factors play in the development of obesity and type 2 diabetes, the implication of different epigenetic processes is being investigated. Although it is well known that the environmental factors can cause cell type-dependent epigenetic changes, inc...

MGMT expression: insights into its regulation. 1. Epigenetic factors

Directory of Open Access Journals (Sweden)

Iatsyshyna A. P.

2013-03-01

Full Text Available O6-methylguanine-DNA methyltransferase (MGMT is the DNA repair enzyme responsible for removing of alkylation adducts from the O6-guanine in DNA. Despite MGMT prevents mutations and cell death, this enzyme can provide resistance of cancer cells to alkylating agents of chemotherapy. The high intra- and inter-individual variations in the human MGMT expression level have been observed indicating to a complicated regulation of this gene. This review is focused on the study of epigenetic factors which could be potentially involved in regulation of the human MGMT gene expression. These include chromatin remodeling via histone modifications and DNA methylation of promoter region and gene body, as well as RNA-based mechanisms, alternative splicing, protein post- translational modifications, and other.

Epigenetic and genetic factors in the cellular response to radiations and DNA-damaging chemicals

International Nuclear Information System (INIS)

Williams, J.R.; D'Arpa, P.

1981-01-01

DNA-damaging agents are widely used as therapeutic tools for a variety of disease states. Many such agents are considered to produce detrimental side effects. Thus, it is important to evaluate both therapeutic efficacy and potential risk. DNA-damaging agents can be so evaluated by comparison to agents whose therapeutic benefit and potential hazards are better known. We propose a framework for such comparison, demonstrating that a simple transformation of cytotoxicity-dose response patterns permits a facile comparison of variation between cells exposed to a single DNA-damaging agent or to different cytotoxic agents. Further, by transforming data from experiments which compare responses of 2 cell populations to an effects ratio, different patterns for the changes in cytotoxicity produced by epigenetic and genetic factors were compared. Using these transformations, we found that there is a wide variation (a factor of 4) between laboratories for a single agent (UVC) and only a slightly larger variation (factor of 6) between normal cell response for different types of DNA-damaging agents (x-ray, UVC, alkylating agents, crosslinking agents). Epigenetic factors such as repair and recovery appear to be a factor only at higher dose levels. Comparison in the cytotoxic effect of a spectrum of DNA-damaging agents in xeroderma pigmentosum, ataxia telangiectasia, and Fanconi's anemia cells indicates significantly different patterns, implying that the effect, and perhaps the nature, of these genetic conditions are quite different

Epigenetics Research on the International Space Station

Science.gov (United States)

Love, John; Cooley, Vic

2016-01-01

The International Space Station (ISS) is a state-of-the orbiting laboratory focused on advancing science and technology research. Experiments being conducted on the ISS include investigations in the emerging field of Epigenetics. Epigenetics refers to stably heritable changes in gene expression or cellular phenotype (the transcriptional potential of a cell) resulting from changes in a chromosome without alterations to the underlying DNA nucleotide sequence (the genetic code), which are caused by external or environmental factors, such as spaceflight microgravity. Molecular mechanisms associated with epigenetic alterations regulating gene expression patterns include covalent chemical modifications of DNA (e.g., methylation) or histone proteins (e.g., acetylation, phorphorylation, or ubiquitination). For example, Epigenetics ("Epigenetics in Spaceflown C. elegans") is a recent JAXA investigation examining whether adaptations to microgravity transmit from one cell generation to another without changing the basic DNA of the organism. Mouse Epigenetics ("Transcriptome Analysis and Germ-Cell Development Analysis of Mice in Space") investigates molecular alterations in organ-specific gene expression patterns and epigenetic modifications, and analyzes murine germ cell development during long term spaceflight, as well as assessing changes in offspring DNA. NASA's first foray into human Omics research, the Twins Study ("Differential effects of homozygous twin astronauts associated with differences in exposure to spaceflight factors"), includes investigations evaluating differential epigenetic effects via comprehensive whole genome analysis, the landscape of DNA and RNA methylation, and biomolecular changes by means of longitudinal integrated multi-omics research. And the inaugural Genes in Space student challenge experiment (Genes in Space-1) is aimed at understanding how epigenetics plays a role in immune system dysregulation by assaying DNA methylation in immune cells

Epigenetic Alteration by DNA Promoter Hypermethylation of Genes Related to Transforming Growth Factor-β (TGF-β Signaling in Cancer

Directory of Open Access Journals (Sweden)

Kiyoshi Mori

2011-03-01

Full Text Available Epigenetic alterations in cancer, especially DNA methylation and histone modification, exert a significant effect on the deregulated expression of cancer-related genes and lay an epigenetic pathway to carcinogenesis and tumor progression. Global hypomethylation and local hypermethylation of CpG islands in the promoter region, which result in silencing tumor suppressor genes, constitute general and major epigenetic modification, the hallmark of the neoplastic epigenome. Additionally, methylation-induced gene silencing commonly affects a number of genes and increases with cancer progression. Indeed, cancers with a high degree of methylation (CpG island methylator phenotype/CIMP do exist and represent a distinct subset of certain cancers including colorectal, bladder and kidney. On the other hand, signals from the microenvironment, especially those from transforming growth factor-β (TGF-β, induce targeted de novo epigenetic alterations of cancer-related genes. While TGF-β signaling has been implicated in two opposite roles in cancer, namely tumor suppression and tumor promotion, its deregulation is also partly induced by epigenetic alteration itself. Although the epigenetic pathway to carcinogenesis and cancer progression has such reciprocal complexity, the important issue is to identify genes or signaling pathways that are commonly silenced in various cancers in order to find early diagnostic and therapeutic targets. In this review, we focus on the epigenetic alteration by DNA methylation and its role in molecular modulations of the TGF-β signaling pathway that cause or underlie altered cancer-related gene expression in both phases of early carcinogenesis and late cancer progression.

H3K9me-independent gene silencing in fission yeast heterochromatin by Clr5 and histone deacetylases

DEFF Research Database (Denmark)

Hansen, Klavs R; Hazan, Idit; Shanker, Sreenath

2011-01-01

organisms such as fission yeast. In spite of numerous studies, the relative contributions of the various heterochromatic histone marks to the properties of heterochromatin remain largely undefined. Here, we report that silencing of the fission yeast mating-type cassettes, which are located in a well......, our results point to histone deacetylases as prominent repressors of gene expression in fission yeast heterochromatin. These deacetylases can act in concert with, or independently of, the widely studied H3K9me mark to influence gene silencing at heterochromatic loci....

Translocations of chromosome end-segments and facultative heterochromatin promote meiotic ring formation in evening primroses.

Science.gov (United States)

Golczyk, Hieronim; Massouh, Amid; Greiner, Stephan

2014-03-01

Due to reciprocal chromosomal translocations, many species of Oenothera (evening primrose) form permanent multichromosomal meiotic rings. However, regular bivalent pairing is also observed. Chiasmata are restricted to chromosomal ends, which makes homologous recombination virtually undetectable. Genetic diversity is achieved by changing linkage relations of chromosomes in rings and bivalents via hybridization and reciprocal translocations. Although the structural prerequisite for this system is enigmatic, whole-arm translocations are widely assumed to be the mechanistic driving force. We demonstrate that this prerequisite is genome compartmentation into two epigenetically defined chromatin fractions. The first one facultatively condenses in cycling cells into chromocenters negative both for histone H3 dimethylated at lysine 4 and for C-banding, and forms huge condensed middle chromosome regions on prophase chromosomes. Remarkably, it decondenses in differentiating cells. The second fraction is euchromatin confined to distal chromosome segments, positive for histone H3 lysine 4 dimethylation and for histone H3 lysine 27 trimethylation. The end-segments are deprived of canonical telomeres but capped with constitutive heterochromatin. This genomic organization promotes translocation breakpoints between the two chromatin fractions, thus facilitating exchanges of end-segments. We challenge the whole-arm translocation hypothesis by demonstrating why reciprocal translocations of chromosomal end-segments should strongly promote meiotic rings and evolution toward permanent translocation heterozygosity. Reshuffled end-segments, each possessing a major crossover hot spot, can furthermore explain meiotic compatibility between genomes with different translocation histories.

The Impact of Environmental Factors in Influencing Epigenetics Related to Oxidative States in the Cardiovascular System

Directory of Open Access Journals (Sweden)

Francesco Angelini

2017-01-01

Full Text Available Oxidative states exert a significant influence on a wide range of biological and molecular processes and functions. When their balance is shifted towards enhanced amounts of free radicals, pathological phenomena can occur, as the generation of reactive oxygen species (ROS in tissue microenvironment or in the systemic circulation can be detrimental. Epidemic chronic diseases of western societies, such as cardiovascular disease, obesity, and diabetes correlate with the imbalance of redox homeostasis. Current advances in our understanding of epigenetics have revealed a parallel scenario showing the influence of oxidative stress as a major regulator of epigenetic gene regulation via modification of DNA methylation, histones, and microRNAs. This has provided both the biological link and a potential molecular explanation between oxidative stress and cardiovascular/metabolic phenomena. Accordingly, in this review, we will provide current insights on the physiological and pathological impact of changes in oxidative states on cardiovascular disorders, by specifically focusing on the influence of epigenetic regulation. A special emphasis will highlight the effect on epigenetic regulation of human’s current life habits, external and environmental factors, including food intake, tobacco, air pollution, and antioxidant-based approaches. Additionally, the strategy to quantify oxidative states in humans in order to determine which biological marker could best match a subject’s profile will be discussed.

The role of non-genetic inheritance in evolutionary rescue: epigenetic buffering, heritable bet hedging and epigenetic traps.

Science.gov (United States)

O'Dea, Rose E; Noble, Daniel W A; Johnson, Sheri L; Hesselson, Daniel; Nakagawa, Shinichi

2016-01-01

Rapid environmental change is predicted to compromise population survival, and the resulting strong selective pressure can erode genetic variation, making evolutionary rescue unlikely. Non-genetic inheritance may provide a solution to this problem and help explain the current lack of fit between purely genetic evolutionary models and empirical data. We hypothesize that epigenetic modifications can facilitate evolutionary rescue through 'epigenetic buffering'. By facilitating the inheritance of novel phenotypic variants that are generated by environmental change-a strategy we call 'heritable bet hedging'-epigenetic modifications could maintain and increase the evolutionary potential of a population. This process may facilitate genetic adaptation by preserving existing genetic variation, releasing cryptic genetic variation and/or facilitating mutations in functional loci. Although we show that examples of non-genetic inheritance are often maladaptive in the short term, accounting for phenotypic variance and non-adaptive plasticity may reveal important evolutionary implications over longer time scales. We also discuss the possibility that maladaptive epigenetic responses may be due to 'epigenetic traps', whereby evolutionarily novel factors (e.g. endocrine disruptors) hack into the existing epigenetic machinery. We stress that more ecologically relevant work on transgenerational epigenetic inheritance is required. Researchers conducting studies on transgenerational environmental effects should report measures of phenotypic variance, so that the possibility of both bet hedging and heritable bet hedging can be assessed. Future empirical and theoretical work is required to assess the relative importance of genetic and epigenetic variation, and their interaction, for evolutionary rescue.

Cow's milk allergy in Dutch children: an epigenetic pilot survey

NARCIS (Netherlands)

Petrus, Nicole C. M.; Henneman, Peter; Venema, Andrea; Mul, Adri; van Sinderen, Femke; Haagmans, Martin; Mook, Olaf; Hennekam, Raoul C.; Sprikkelman, Aline B.; Mannens, Marcel

2016-01-01

Background: Cow's milk allergy (CMA) is a common disease in infancy. Early environmental factors are likely to contribute to CMA. It is known that epigenetic gene regulation can be altered by environmental factors. We have set up a proof of concept study, aiming to detect epigenetic associations

Comparative in silico profiling of epigenetic modifiers in human tissues.

Science.gov (United States)

Son, Mi-Young; Jung, Cho-Rok; Kim, Dae-Soo; Cho, Hyun-Soo

2018-04-06

The technology of tissue differentiation from human pluripotent stem cells has attracted attention as a useful resource for regenerative medicine, disease modeling and drug development. Recent studies have suggested various key factors and specific culture methods to improve the successful tissue differentiation and efficient generation of human induced pluripotent stem cells. Among these methods, epigenetic regulation and epigenetic signatures are regarded as an important hurdle to overcome during reprogramming and differentiation. Thus, in this study, we developed an in silico epigenetic panel and performed a comparative analysis of epigenetic modifiers in the RNA-seq results of 32 human tissues. We demonstrated that an in silico epigenetic panel can identify epigenetic modifiers in order to overcome epigenetic barriers to tissue-specific differentiation.

Epigenetic switch involved in activation of pioneer factor FOXA1-dependent enhancers

Science.gov (United States)

Sérandour, Aurélien A.; Avner, Stéphane; Percevault, Frédéric; Demay, Florence; Bizot, Maud; Lucchetti-Miganeh, Céline; Barloy-Hubler, Frédérique; Brown, Myles; Lupien, Mathieu; Métivier, Raphaël; Salbert, Gilles; Eeckhoute, Jérôme

2011-01-01

Transcription factors (TFs) bind specifically to discrete regions of mammalian genomes called cis-regulatory elements. Among those are enhancers, which play key roles in regulation of gene expression during development and differentiation. Despite the recognized central regulatory role exerted by chromatin in control of TF functions, much remains to be learned regarding the chromatin structure of enhancers and how it is established. Here, we have analyzed on a genomic-scale enhancers that recruit FOXA1, a pioneer transcription factor that triggers transcriptional competency of these cis-regulatory sites. Importantly, we found that FOXA1 binds to genomic regions showing local DNA hypomethylation and that its cell-type-specific recruitment to chromatin is linked to differential DNA methylation levels of its binding sites. Using neural differentiation as a model, we showed that induction of FOXA1 expression and its subsequent recruitment to enhancers is associated with DNA demethylation. Concomitantly, histone H3 lysine 4 methylation is induced at these enhancers. These epigenetic changes may both stabilize FOXA1 binding and allow for subsequent recruitment of transcriptional regulatory effectors. Interestingly, when cloned into reporter constructs, FOXA1-dependent enhancers were able to recapitulate their cell type specificity. However, their activities were inhibited by DNA methylation. Hence, these enhancers are intrinsic cell-type-specific regulatory regions of which activities have to be potentiated by FOXA1 through induction of an epigenetic switch that includes notably DNA demethylation. PMID:21233399

Genome-wide profiling of transcription factor binding and epigenetic marks in adipocytes by ChIP-seq

DEFF Research Database (Denmark)

Nielsen, Ronni; Mandrup, Susanne

2014-01-01

of the most widely used of these technologies. Using these methods, association of transcription factors, cofactors, and epigenetic marks can be mapped to DNA in a genome-wide manner. Here, we provide a detailed protocol for performing ChIP-seq analyses in preadipocytes and adipocytes. We have focused mainly...

Potential of Epigenetic Therapies in Non-cancerous Conditions

Directory of Open Access Journals (Sweden)

Raymond eYung

2014-12-01

Full Text Available There has been an explosion of knowledge in the epigenetics field in the past 20 years. The first epigenetic therapies have arrived in the clinic for cancer treatments. In contrast, much of the promise of epigenetic therapies for non-cancerous conditions remains in the laboratories. The current review will focus on the recent progress that has been made in understanding the pathogenic role of epigenetics in immune and inflammatory conditions, and how the knowledge may provide much needed new therapeutic targets for many autoimmune diseases. Dietary factors are increasingly recognized as potential modifiers of epigenetic marks that can influence health and diseases across generations. The current epigenomics revolution will almost certainly complement the explosion of personal genetics medicine to help guide treatment decisions and disease risk stratification.

Epigenetic effects of ionizing radiation

International Nuclear Information System (INIS)

EI-Naggar, A.M.

2007-01-01

Data generated during the last three decades provide evidence of Epigenetic Effects that ave-induced by ionizing radiation, particularly those of high LET values, and low level dose exposures. Epigenesist is defined as the stepwise process by which genetic information, as modified by environmental influences, is translated into the substance and behavior of cells, tissues, organism.The epigenetic effects cited in the literature are essentially classified into fine types depending on the type and nature of the effect induced.The most accepted postulation, for the occurrence of these epigenetic effects, is a radiation induced bio electric disturbances in the environment of the non-irradiated cellular volume. This will trigger signals that will induce effects in the unirradiated cells.The epigenetic effects referenced in the literature up to date are five types; namely, Genomic Instability, Bystander. Effects, Clastogenic Plasma Factors,, Abscopal Effects, and Tran generational Effects.The demonstration of Epigenetic Effects associated with exposure to ionizing radiation indicates the need to re- examine the concept of radiation dose and target size. Also an improved understanding of qualifiring and quantifying radiation risk estimates may be attained. Also, a more logical means to understand the underlying mechanisms of radiation induced carcinogenic transformation of cells

Genetics and epigenetics of obesity.

Science.gov (United States)

Herrera, Blanca M; Keildson, Sarah; Lindgren, Cecilia M

2011-05-01

Obesity results from interactions between environmental and genetic factors. Despite a relatively high heritability of common, non-syndromic obesity (40-70%), the search for genetic variants contributing to susceptibility has been a challenging task. Genome wide association (GWA) studies have dramatically changed the pace of detection of common genetic susceptibility variants. To date, more than 40 genetic variants have been associated with obesity and fat distribution. However, since these variants do not fully explain the heritability of obesity, other forms of variation, such as epigenetics marks, must be considered. Epigenetic marks, or "imprinting", affect gene expression without actually changing the DNA sequence. Failures in imprinting are known to cause extreme forms of obesity (e.g. Prader-Willi syndrome), but have also been convincingly associated with susceptibility to obesity. Furthermore, environmental exposures during critical developmental periods can affect the profile of epigenetic marks and result in obesity. We review the most recent evidence for genetic and epigenetic mechanisms involved in the susceptibility and development of obesity. Only a comprehensive understanding of the underlying genetic and epigenetic mechanisms, and the metabolic processes they govern, will allow us to manage, and eventually prevent, obesity. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Epigenetics, eh! A meeting summary of the Canadian Conference on Epigenetics.

Science.gov (United States)

Rodenhiser, David I; Bérubé, Nathalie G; Mann, Mellissa R W

2011-10-01

In May 2011, the Canadian Conference on Epigenetics: Epigenetics Eh! was held in London, Canada. The objectives of this conference were to showcase the breadth of epigenetic research on environment and health across Canada and to provide the catalyst to develop collaborative Canadian epigenetic research opportunities, similar to existing international epigenetic initiatives in the US and Europe. With ten platform sessions and two sessions with over 100 poster presentations, this conference featured cutting-edge epigenetic research, presented by Canadian and international principal investigators and their trainees in the field of epigenetics and chromatin dynamics. An EpigenART competition included ten artists, creating a unique opportunity for artists and scientists to interact and explore their individual interpretations of this scientific discipline. The conference provided a unique venue for a significant cross-section of Canadian epigenetic researchers from diverse disciplines to meet, interact, collaborate and strategize at the national level.

The age-dependent epigenetic and physiological changes in an Arabidopsis T87 cell suspension culture during long-term cultivation

Energy Technology Data Exchange (ETDEWEB)

Kwiatkowska, Aleksandra, E-mail: A.Kwiatkows@gmail.com [Department of Botany, University of Rzeszow, Kolbuszowa (Poland); Zebrowski, Jacek [Department of Plant Physiology, University of Rzeszow, Kolbuszowa (Poland); Oklejewicz, Bernadetta [Department of Genetics, University of Rzeszow, Kolbuszowa (Poland); Czarnik, Justyna [Department of Botany, University of Rzeszow, Kolbuszowa (Poland); Halibart-Puzio, Joanna [Department of Plant Physiology, University of Rzeszow, Kolbuszowa (Poland); Wnuk, Maciej [Department of Genetics, University of Rzeszow, Kolbuszowa (Poland)

2014-05-02

Highlights: • A decrease in proliferation rate during long-term cultivation of Arabidopsis cells. • Age-dependent increase in senescence-associated gene expression in Arabidopsis cells. • Age-related increase in DNA methylation, H3K9me2, and H3K27me3 in Arabidopsis cells. • High potential of photosynthetic efficiency of long-term cultured Arabidopsis cells. - Abstract: Plant cell suspension cultures represent good model systems applicable for both basic research and biotechnological purposes. Nevertheless, it is widely known that a prolonged in vitro cultivation of plant cells is associated with genetic and epigenetic instabilities, which may limit the usefulness of plant lines. In this study, the age-dependent epigenetic and physiological changes in an asynchronous Arabidopsis T87 cell culture were examined. A prolonged cultivation period was found to be correlated with a decrease in the proliferation rate and a simultaneous increase in the expression of senescence-associated genes, indicating that the aging process started at the late growth phase of the culture. In addition, increases in the heterochromatin-specific epigenetic markers, i.e., global DNA methylation, H3K9 dimethylation, and H3K27 trimethylation, were observed, suggesting the onset of chromatin condensation, a hallmark of the early stages of plant senescence. Although the number of live cells decreased with an increase in the age of the culture, the remaining viable cells retained a high potential to efficiently perform photosynthesis and did not exhibit any symptoms of photosystem II damage.

The age-dependent epigenetic and physiological changes in an Arabidopsis T87 cell suspension culture during long-term cultivation

International Nuclear Information System (INIS)

Kwiatkowska, Aleksandra; Zebrowski, Jacek; Oklejewicz, Bernadetta; Czarnik, Justyna; Halibart-Puzio, Joanna; Wnuk, Maciej

2014-01-01

Highlights: • A decrease in proliferation rate during long-term cultivation of Arabidopsis cells. • Age-dependent increase in senescence-associated gene expression in Arabidopsis cells. • Age-related increase in DNA methylation, H3K9me2, and H3K27me3 in Arabidopsis cells. • High potential of photosynthetic efficiency of long-term cultured Arabidopsis cells. - Abstract: Plant cell suspension cultures represent good model systems applicable for both basic research and biotechnological purposes. Nevertheless, it is widely known that a prolonged in vitro cultivation of plant cells is associated with genetic and epigenetic instabilities, which may limit the usefulness of plant lines. In this study, the age-dependent epigenetic and physiological changes in an asynchronous Arabidopsis T87 cell culture were examined. A prolonged cultivation period was found to be correlated with a decrease in the proliferation rate and a simultaneous increase in the expression of senescence-associated genes, indicating that the aging process started at the late growth phase of the culture. In addition, increases in the heterochromatin-specific epigenetic markers, i.e., global DNA methylation, H3K9 dimethylation, and H3K27 trimethylation, were observed, suggesting the onset of chromatin condensation, a hallmark of the early stages of plant senescence. Although the number of live cells decreased with an increase in the age of the culture, the remaining viable cells retained a high potential to efficiently perform photosynthesis and did not exhibit any symptoms of photosystem II damage

Methyl CpG–binding proteins induce large-scale chromatin reorganization during terminal differentiation

Science.gov (United States)

Brero, Alessandro; Easwaran, Hariharan P.; Nowak, Danny; Grunewald, Ingrid; Cremer, Thomas; Leonhardt, Heinrich; Cardoso, M. Cristina

2005-01-01

Pericentric heterochromatin plays an important role in epigenetic gene regulation. We show that pericentric heterochromatin aggregates during myogenic differentiation. This clustering leads to the formation of large chromocenters and correlates with increased levels of the methyl CpG–binding protein MeCP2 and pericentric DNA methylation. Ectopic expression of fluorescently tagged MeCP2 mimicked this effect, causing a dose-dependent clustering of chromocenters in the absence of differentiation. MeCP2-induced rearrangement of heterochromatin occurred throughout interphase, did not depend on the H3K9 histone methylation pathway, and required the methyl CpG–binding domain (MBD) only. Similar to MeCP2, another methyl CpG–binding protein, MBD2, also increased during myogenic differentiation and could induce clustering of pericentric regions, arguing for functional redundancy. This MeCP2- and MBD2-mediated chromatin reorganization may thus represent a molecular link between nuclear genome topology and the epigenetic maintenance of cellular differentiation. PMID:15939760

Epigenetics primer: why the clinician should care about epigenetics.

Science.gov (United States)

Duarte, Julio D

2013-12-01

Epigenetics describes heritable alterations of gene expression that do not involve DNA sequence variation and are changeable throughout an organism's lifetime. Not only can epigenetic status influence drug response, but it can also be modulated by drugs. In this review, the three major epigenetic mechanisms are described: covalent DNA modification, histone protein modification, and regulation by noncoding RNA. Further, this review describes how drug therapy can influence, and be influenced by, these mechanisms. Drugs with epigenetic mechanisms are already in use, with many more likely to be approved within the next few years. As the understanding of epigenetic processes improves, so will the ability to use these data in the clinic to improve patient care. © 2013 Pharmacotherapy Publications, Inc.

Epigenetic rejuvenation.

Science.gov (United States)

Manukyan, Maria; Singh, Prim B

2012-05-01

Induced pluripotent stem (iPS) cells have provided a rational means of obtaining histo-compatible tissues for 'patient-specific' regenerative therapies (Hanna et al. 2010; Yamanaka & Blau 2010). Despite the obvious potential of iPS cell-based therapies, there are certain problems that must be overcome before these therapies can become safe and routine (Ohi et al. 2011; Pera 2011). As an alternative, we have recently explored the possibility of using 'epigenetic rejuvenation', where the specialized functions of an old cell are rejuvenated in the absence of any change in its differentiated state (Singh & Zacouto 2010). The mechanism(s) that underpin 'epigenetic rejuvenation' are unknown and here we discuss model systems, using key epigenetic modifiers, which might shed light on the processes involved. Epigenetic rejuvenation has advantages over iPS cell techniques that are currently being pursued. First, the genetic and epigenetic abnormalities that arise through the cycle of dedifferentiation of somatic cells to iPS cells followed by redifferentiation of iPS cells into the desired cell type are avoided (Gore et al. 2011; Hussein et al. 2011; Pera 2011): epigenetic rejuvenation does not require passage through the de-/redifferentiation cycle. Second, because the aim of epigenetic rejuvenation is to ensure that the differentiated cell type retains its specialized function it makes redundant the question of transcriptional memory that is inimical to iPS cell-based therapies (Ohi et al. 2011). Third, to produce unrelated cell types using the iPS technology takes a long time, around three weeks, whereas epigenetic rejuvenation of old cells will take only a matter of days. Epigenetic rejuvenation provides the most safe, rapid and cheap route to successful regenerative medicine. © 2012 The Authors. Journal compilation © 2012 by the Molecular Biology Society of Japan/Blackwell Publishing Ltd.

Epigenetics of early-life lead exposure and effects on brain development.

Science.gov (United States)

Senut, Marie-Claude; Cingolani, Pablo; Sen, Arko; Kruger, Adele; Shaik, Asra; Hirsch, Helmut; Suhr, Steven T; Ruden, Douglas

2012-12-01

The epigenetic machinery plays a pivotal role in the control of many of the body's key cellular functions. It modulates an array of pliable mechanisms that are readily and durably modified by intracellular or extracellular factors. In the fast-moving field of neuroepigenetics, it is emerging that faulty epigenetic gene regulation can have dramatic consequences on the developing CNS that can last a lifetime and perhaps even affect future generations. Mounting evidence suggests that environmental factors can impact the developing brain through these epigenetic mechanisms and this report reviews and examines the epigenetic effects of one of the most common neurotoxic pollutants of our environment, which is believed to have no safe level of exposure during human development: lead.

Dynamic epigenetic responses to muscle contraction

DEFF Research Database (Denmark)

Rasmussen, Morten; Zierath, Juleen R; Barrès, Romain

2014-01-01

Skeletal muscle is a malleable organ that responds to a single acute exercise bout by inducing the expression of genes involved in structural, metabolic and functional adaptations. Several epigenetic mechanisms including histone H4 deacetylation and loss of promoter methylation have been implicated...... in modifying exercise-responsive gene expression. These transient changes suggest that epigenetic mechanisms are not restricted to early stages of human development but are broad dynamic controllers of genomic plasticity in response to environmental factors....

Epigenetic Regulation of Telomere Maintenance

Czech Academy of Sciences Publication Activity Database

Fojtová, M.; Fajkus, Jiří

2014-01-01

Roč. 143, 1-3 (2014), s. 125-135 ISSN 1424-8581 Institutional support: RVO:68081707 Keywords : Chromatin * DNA methylation * Epigenetic s Subject RIV: BO - Biophysics Impact factor: 1.561, year: 2014

Epigenetics of hypoxic pulmonary arterial hypertension following intrauterine growth retardation rat: epigenetics in PAH following IUGR

Directory of Open Access Journals (Sweden)

Xu Xue-Feng

2013-02-01

Full Text Available Abstract Background Accumulating evidence reveals that intrauterine growth retardation (IUGR can cause varying degrees of pulmonary arterial hypertension (PAH later in life. Moreover, epigenetics plays an important role in the fetal origin of adult disease. The goal of this study was to investigate the role of epigenetics in the development of PAH following IUGR. Methods The IUGR rats were established by maternal undernutrition during pregnancy. Pulmonary vascular endothelial cells (PVEC were isolated from the rat lungs by magnetic-activated cell sorting (MACS. We investigated epigenetic regulation of the endothelin-1 (ET-1 gene in PVEC of 1-day and 6-week IUGR rats, and response of IUGR rats to hypoxia. Results The maternal nutrient restriction increased the histone acetylation and hypoxia inducible factor-1α (HIF-1α binding levels in the ET-1 gene promoter of PVEC in IUGR newborn rats, and continued up to 6 weeks after birth. These epigenetic changes could result in an IUGR rat being highly sensitive to hypoxia later in life, causing more significant PAH or pulmonary vascular remodeling. Conclusions These findings suggest that epigenetics is closely associated with the development of hypoxic PAH following IUGR, further providing a new insight for improved prevention and treatment of IUGR-related PAH.

The epigenetic landscape of latent Kaposi sarcoma-associated herpesvirus genomes.

Directory of Open Access Journals (Sweden)

Thomas Günther

Full Text Available Herpesvirus latency is generally thought to be governed by epigenetic modifications, but the dynamics of viral chromatin at early timepoints of latent infection are poorly understood. Here, we report a comprehensive spatial and temporal analysis of DNA methylation and histone modifications during latent infection with Kaposi Sarcoma-associated herpesvirus (KSHV, the etiologic agent of Kaposi Sarcoma and primary effusion lymphoma (PEL. By use of high resolution tiling microarrays in conjunction with immunoprecipitation of methylated DNA (MeDIP or modified histones (chromatin IP, ChIP, our study revealed highly distinct landscapes of epigenetic modifications associated with latent KSHV infection in several tumor-derived cell lines as well as de novo infected endothelial cells. We find that KSHV genomes are subject to profound methylation at CpG dinucleotides, leading to the establishment of characteristic global DNA methylation patterns. However, such patterns evolve slowly and thus are unlikely to control early latency. In contrast, we observed that latency-specific histone modification patterns were rapidly established upon a de novo infection. Our analysis furthermore demonstrates that such patterns are not characterized by the absence of activating histone modifications, as H3K9/K14-ac and H3K4-me3 marks were prominently detected at several loci, including the promoter of the lytic cycle transactivator Rta. While these regions were furthermore largely devoid of the constitutive heterochromatin marker H3K9-me3, we observed rapid and widespread deposition of H3K27-me3 across latent KSHV genomes, a bivalent modification which is able to repress transcription in spite of the simultaneous presence of activating marks. Our findings suggest that the modification patterns identified here induce a poised state of repression during viral latency, which can be rapidly reversed once the lytic cycle is induced.

Epigenetics: relevance and implications for public health.

Science.gov (United States)

Rozek, Laura S; Dolinoy, Dana C; Sartor, Maureen A; Omenn, Gilbert S

2014-01-01

Improved understanding of the multilayer regulation of the human genome has led to a greater appreciation of environmental, nutritional, and epigenetic risk factors for human disease. Chromatin remodeling, histone tail modifications, and DNA methylation are dynamic epigenetic changes responsive to external stimuli. Careful interpretation can provide insights for actionable public health through collaboration between population and basic scientists and through integration of multiple data sources. We review key findings in environmental epigenetics both in human population studies and in animal models, and discuss the implications of these results for risk assessment and public health protection. To ultimately succeed in identifying epigenetic mechanisms leading to complex phenotypes and disease, researchers must integrate the various animal models, human clinical approaches, and human population approaches while paying attention to life-stage sensitivity, to generate effective prescriptions for human health evaluation and disease prevention.

Epigenetics and the Developmental Origins of Health and ...

Science.gov (United States)

Epigenetic programming is likely to be an important mechanism underlying the lasting influence of the developmental environment on lifelong health, a concept known as the Developmental Origins of Health and Disease (DOHaD). DNA methylation, posttranslational histone protei n modifications, noncoding RNAs and recruited protein complexes are elements of the epigenetic regulation of gene transcription. These heritable but reversible changes in gene function are dynamic and labile during specific stages of the reproductive cycle and development. Epigenetic marks may be maintained throughout an individual's lifespan and can alter the life-long risk of disease; the nature of these epigenetic marks and their potential alteration by environmental factors is an area of active research. This chapter provides an overview of epigenetic regulation, particularly as it occurs as an essential component of embryo-fetal development. In this chapter we will present key features of DNA methylation and histone protein modifications, including the enzymes involved and the effects of these modifications on gene transcription. We will discuss the interplay of these dynamic modifications and the emerging role of noncoding RNAs in epigenetic gene regulation.

Epigenetics and Evolution: Transposons and the Stochastic Epigenetic Modification Model

Directory of Open Access Journals (Sweden)

Sergio Branciamore

2015-04-01

Full Text Available In addition to genetic variation, epigenetic variation and transposons can greatly affect the evolutionary fitnesses landscape and gene expression. Previously we proposed a mathematical treatment of a general epigenetic variation model that we called Stochastic Epigenetic Modification (SEM model. In this study we follow up with a special case, the Transposon Silencing Model (TSM, with, once again, emphasis on quantitative treatment. We have investigated the evolutionary effects of epigenetic changes due to transposon (T insertions; in particular, we have considered a typical gene locus A and postulated that (i the expression level of gene A depends on the epigenetic state (active or inactive of a cis- located transposon element T, (ii stochastic variability in the epigenetic silencing of T occurs only in a short window of opportunity during development, (iii the epigenetic state is then stable during further development, and (iv the epigenetic memory is fully reset at each generation. We develop the model using two complementary approaches: a standard analytical population genetics framework (di usion equations and Monte-Carlo simulations. Both approaches led to similar estimates for the probability of fixation and time of fixation of locus TA with initial frequency P in a randomly mating diploid population of effective size Ne. We have ascertained the e ect that ρ, the probability of transposon Modification during the developmental window, has on the population (species. One of our principal conclusions is that as ρ increases, the pattern of fixation of the combined TA locus goes from "neutral" to "dominant" to "over-dominant". We observe that, under realistic values of ρ, epigenetic Modifications can provide an e cient mechanism for more rapid fixation of transposons and cis-located gene alleles. The results obtained suggest that epigenetic silencing, even if strictly transient (being reset at each generation, can still have signi cant

Aberrant Transforming Growth Factor β1 Signaling and SMAD4 Nuclear Translocation Confer Epigenetic Repression of ADAM19 in Ovarian Cancer

Directory of Open Access Journals (Sweden)

Michael W.Y. Chan

2008-09-01

Full Text Available Transforming growth factor-beta (TGF-β/SMAD signaling is a key growth regulatory pathway often dysregulated in ovarian cancer and other malignancies. Although loss of TGF-β–mediated growth inhibition has been shown to contribute to aberrant cell behavior, the epigenetic consequence(s of impaired TGF-β/SMAD signaling on target genes is not well established. In this study, we show that TGF-β1 causes growth inhibition of normal ovarian surface epithelial cells, induction of nuclear translocation SMAD4, and up-regulation of ADAM19 (a disintegrin and metalloprotease domain 19, a newly identified TGF-β1 target gene. Conversely, induction and nuclear translocation of SMAD4 were negligible in ovarian cancer cells refractory to TGF-β1 stimulation, and ADAM19 expression was greatly reduced. Furthermore, in the TGF-β1 refractory cells, an inactive chromatin environment, marked by repressive histone modifications (trimethyl-H3K27 and dimethyl-H3K9 and histone deacetylase, was associated with the ADAM19 promoter region. However, the CpG island found within the promoter and first exon of ADAM19 remained generally unmethylated. Although disrupted growth factor signaling has been linked to epigenetic gene silencing in cancer, this is the first evidence demonstrating that impaired TGF-β1 signaling can result in the formation of a repressive chromatin state and epigenetic suppression of ADAM19. Given the emerging role of ADAMs family proteins in growth factor regulation in normal cells, we suggest that epigenetic dysregulation of ADAM19 may contribute to the neoplastic process in ovarian cancer.

Heterochromatin heterogeneity in Hypostomus prope unae (Steindachner, 1878 (Siluriformes, Loricariidae from Northeastern Brazil

Directory of Open Access Journals (Sweden)

Jamille Bitencourt

2011-11-01

Full Text Available Cytogenetic analyses using C-banding and chromosomal digestion by several restriction enzymes were carried out in four populations (named A, B, C and D of Hypostomus prope unae (Loricariidae, Hypostominae from Contas river basin, northeastern Brazil. These populations share 2n=76 and single NORs on the second metacentric pair but exclusive karyotype forms for each locality. Populations A and B presented conspicuous terminal and interstitial heterochromatic blocks on most of acrocentric chromosomes and equivalent to NORs with differences in both position and bearing pair. Population D showed evident marks at interstitial regions and interspersed with nucleolar region while population C presented interstitial and terminal heterochromatin segments, non-coincident with NORs. The banding pattern after digestion with the endonucleases Alu I, Bam HI, Hae III and Dde I revealed a remarkable heterogeneity within heterochromatin, allowing the identification of distinctive clusters of repeated DNA in the studied populations, besides specific patterns along euchromatic regions. The analysis using restriction enzymes has proved to be highly informative, characterizing population differences and peculiarities in the genome organization of H. prope unae.

The epigenetics of obesity

Science.gov (United States)

Maternal nutrition at the time of conception and during pregnancy is considered a factor for individual differences in having obesity. The mechanisms underlying this association are likely partially epigenetic in nature, but pinning down the exact nature, location, and timing of these changes remain...

Epigenetic transmission of Holocaust trauma: can nightmares be inherited?

Science.gov (United States)

Kellermann, Natan Pf

2013-01-01

The Holocaust left its visible and invisible marks not only on the survivors, but also on their children. Instead of numbers tattooed on their forearms, however, they may have been marked epigenetically with a chemical coating upon their chromosomes, which would represent a kind of biological memory of what the parents experienced. as a result, some suffer from a general vulnerability to stress while others are more resilient. Previous research assumed that such transmission was caused by environmental factors, such as the parents' childrearing behavior. New research, however, indicates that these transgenerational effects may have been also (epi) genetically transmitted to their children. Integrating both hereditary and environmental factors, epigenetics adds a new and more comprehensive psychobiological dimension to the explanation of transgenerational transmission of trauma. Specifically, epigenetics may explain why latent transmission becomes manifest under stress. a general theoretical overview of epigenetics and its relevance to research on trauma transmission is presented.

Translocations of Chromosome End-Segments and Facultative Heterochromatin Promote Meiotic Ring Formation in Evening Primroses[W][OPEN

Science.gov (United States)

Golczyk, Hieronim; Massouh, Amid; Greiner, Stephan

2014-01-01

Due to reciprocal chromosomal translocations, many species of Oenothera (evening primrose) form permanent multichromosomal meiotic rings. However, regular bivalent pairing is also observed. Chiasmata are restricted to chromosomal ends, which makes homologous recombination virtually undetectable. Genetic diversity is achieved by changing linkage relations of chromosomes in rings and bivalents via hybridization and reciprocal translocations. Although the structural prerequisite for this system is enigmatic, whole-arm translocations are widely assumed to be the mechanistic driving force. We demonstrate that this prerequisite is genome compartmentation into two epigenetically defined chromatin fractions. The first one facultatively condenses in cycling cells into chromocenters negative both for histone H3 dimethylated at lysine 4 and for C-banding, and forms huge condensed middle chromosome regions on prophase chromosomes. Remarkably, it decondenses in differentiating cells. The second fraction is euchromatin confined to distal chromosome segments, positive for histone H3 lysine 4 dimethylation and for histone H3 lysine 27 trimethylation. The end-segments are deprived of canonical telomeres but capped with constitutive heterochromatin. This genomic organization promotes translocation breakpoints between the two chromatin fractions, thus facilitating exchanges of end-segments. We challenge the whole-arm translocation hypothesis by demonstrating why reciprocal translocations of chromosomal end-segments should strongly promote meiotic rings and evolution toward permanent translocation heterozygosity. Reshuffled end-segments, each possessing a major crossover hot spot, can furthermore explain meiotic compatibility between genomes with different translocation histories. PMID:24681616

Nutrients and the Pancreas: An Epigenetic Perspective

Directory of Open Access Journals (Sweden)

Andee Weisbeck

2017-03-01

Full Text Available Pancreatic cancer is the fourth most common cause of cancer-related deaths with a dismal average five-year survival rate of six percent. Substitutional progress has been made in understanding how pancreatic cancer develops and progresses. Evidence is mounting which demonstrates that diet and nutrition are key factors in carcinogenesis. In particular, diets low in folate and high in fruits, vegetables, red/processed meat, and saturated fat have been identified as pancreatic cancer risk factors with a proposed mechanism involving epigenetic modifications or gene regulation. We review the current literature assessing the correlation between diet, epigenetics, and pancreatic cancer.

Epigenetic control of effectors in plant pathogens

Directory of Open Access Journals (Sweden)

Mark eGijzen

2014-11-01

Full Text Available Plant pathogens display impressive versatility in adapting to host immune systems. Pathogen effector proteins facilitate disease but can become avirulence (Avr factors when the host acquires discrete recognition capabilities that trigger immunity. The mechanisms that lead to changes to pathogen Avr factors that enable escape from host immunity are diverse, and include epigenetic switches that allow for reuse or recycling of effectors. This perspective outlines possibilities of how epigenetic control of Avr effector gene expression may have arisen and persisted in plant pathogens, and how it presents special problems for diagnosis and detection of specific pathogen strains or pathotypes.

[Epigenetics and obesity].

Science.gov (United States)

Casanello, Paola; Krause, Bernardo J; Castro-Rodríguez, José A; Uauy, Ricardo

Current evidence supports the notion that exposure to various environmental conditions in early life may induce permanent changes in the epigenome that persist throughout the life-course. This article focuses on early changes associated with obesity in adult life. A review is presented on the factors that induce changes in whole genome (DNA) methylation in early life that are associated with adult onset obesity and related disorders. In contrast, reversal of epigenetic changes associated with weight loss in obese subjects has not been demonstrated. This contrasts with well-established associations found between obesity related DNA methylation patterns at birth and adult onset obesity and diabetes. Epigenetic markers may serve to screen indivuals at risk for obesity and assess the effects of interventions in early life that may delay or prevent obesity in early life. This might contribute to lower the obesity-related burden of death and disability at the population level. The available evidence indicates that epigenetic marks are in fact modifiable, based on modifications in the intrauterine environment and changes in food intake, physical activity and dietary patterns patterns during pregnancy and early years of adult life. This offers the opportunity to intervene before conception, during pregnancy, infancy, childhood, and also in later life. There must be documentation on the best preventive actions in terms of diet and physical activity that will modify or revert the adverse epigenetic markers, thus preventing obesity and diabetes in suceptible individuals and populations. Copyright © 2016 Sociedad Chilena de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

At the Frontier of Epigenetics of Brain Sex Differences

OpenAIRE

Margaret M Mccarthy; Bridget M Nugent

2015-01-01

The notion that epigenetics may play an important role in the establishment and maintenance of sex differences in the brain has garnered great enthusiasm but the reality in terms of actual advances has been slow. Two general approaches include the comparison of a particular epigenetic mark in males vs. females and the inhibition of key epigenetic enzymes or co-factors to determine if this eliminates a particular sex difference in brain or behavior. The majority of emphasis has been on candida...

Advances in epigenetics and epigenomics for neurodegenerative diseases.

Science.gov (United States)

Qureshi, Irfan A; Mehler, Mark F

2011-10-01

In the post-genomic era, epigenetic factors-literally those that are "over" or "above" genetic ones and responsible for controlling the expression and function of genes-have emerged as important mediators of development and aging; gene-gene and gene-environmental interactions; and the pathophysiology of complex disease states. Here, we provide a brief overview of the major epigenetic mechanisms (ie, DNA methylation, histone modifications and chromatin remodeling, and non-coding RNA regulation). We highlight the nearly ubiquitous profiles of epigenetic dysregulation that have been found in Alzheimer's and other neurodegenerative diseases. We also review innovative methods and technologies that enable the characterization of individual epigenetic modifications and more widespread epigenomic states at high resolution. We conclude that, together with complementary genetic, genomic, and related approaches, interrogating epigenetic and epigenomic profiles in neurodegenerative diseases represent important and increasingly practical strategies for advancing our understanding of and the diagnosis and treatment of these disorders.

Prolonged re-expression of the hypermethylated gene EPB41L3 using artificial transcription factors and epigenetic drugs

NARCIS (Netherlands)

Huisman, Christian; van der Wijst, Monique G. P.; Falahi, Fahimeh; Overkamp, Juul; Karsten, Gellert; Terpstra, Martijn M.; Kok, Klaas; van der Zee, Ate G. J.; Schuuring, Ed; Wisman, G. Bea A.; Rots, Marianne G.

2015-01-01

Epigenetic silencing of tumor suppressor genes (TSGs) is considered a significant event in the progression of cancer. For example, EPB41L3, a potential biomarker in cervical cancer, is often silenced by cancer-specific promoter methylation. Artificial transcription factors (ATFs) are unique tools to

Epigenetic subgroups of esophageal and gastric adenocarcinoma with differential GATA5 DNA methylation associated with clinical and lifestyle factors.

Directory of Open Access Journals (Sweden)

Xinhui Wang

Full Text Available BACKGROUND: Adenocarcinomas located near the gastroesophageal junction have unclear etiology and are difficult to classify. We used DNA methylation analysis to identify subtype-specific markers and new subgroups of gastroesophageal adenocarcinomas, and studied their association with epidemiological risk factors and clinical outcomes. METHODOLOGY/PRINCIPAL FINDINGS: We used logistic regression models and unsupervised hierarchical cluster analysis of 74 DNA methylation markers on 45 tumor samples (44 patients of esophageal and gastric adenocarcinomas obtained from a population-based case-control study to uncover epigenetic markers and cluster groups of gastroesophageal adenocarcinomas. No distinct epigenetic differences were evident between subtypes of gastric and esophageal cancers. However, we identified two gastroesophageal adenocarcinoma subclusters based on DNA methylation profiles. Group membership was best predicted by GATA5 DNA methylation status. We analyzed the associations between these two epigenetic groups and exposure using logistic regression, and the associations with survival time using Cox regression in a larger set of 317 tumor samples (278 patients. There were more males with esophageal and gastric cardia cancers in Cluster Group 1 characterized by higher GATA5 DNA methylation values (all p<0.05. This group also showed associations of borderline statistical significance with having ever smoked (p-value = 0.07, high body mass index (p-value = 0.06, and symptoms of gastroesophageal reflux (p-value = 0.07. Subjects in cluster Group 1 showed better survival than those in Group 2 after adjusting for tumor differentiation grade, but this was not found to be independent of tumor stage. CONCLUSIONS/SIGNIFICANCE: DNA methylation profiling can be used in population-based studies to identify epigenetic subclasses of gastroesophageal adenocarcinomas and class-specific DNA methylation markers that can be linked to

Heterochromatin marks HP1γ, HP1α and H3K9me3, and DNA damage response activation in human testis development and germ cell tumours

DEFF Research Database (Denmark)

Bartkova, J; Moudry, P; Hodny, Z

2011-01-01

activation in CIS; and enhanced HP1α in teratoma structures with epithelial and neuronal differentiation. Differential expression of the three heterochromatin markers suggests their partly non-overlapping roles, and separation of heterochromatinization from DDR activation highlights distinct responses...

Neurofibromatosis-Noonan Syndrome: A Possible Paradigm of the Combination of Genetic and Epigenetic Factors.

Science.gov (United States)

Yapijakis, Christos; Pachis, Nikos; Voumvourakis, Costas

2017-01-01

Neurofibromatosis-Noonan syndrome (NFNS) is a clinical entity possessing traits of autosomal dominant disorders neurofibromatosis type 1 (NF1) and Noonan syndrome (NS). Germline mutations that disrupt the RAS/MAPK pathway are involved in the pathogenesis of both NS and NF1. In light of a studied Greek family, a new theory for etiological pathogenesis of NFNS is suggested. The NFNS phenotype may be the final result of a combination of a genetic factor (a mutation in the NF1 gene) and an environmental factor with the epigenetic effects of muscle hypotonia (such as hydantoin in the reported Greek family), causing hypoplasia of the face and micrognathia.

Epigenetic memory in mammals

Directory of Open Access Journals (Sweden)

Zoe eMigicovsky

2011-06-01

Full Text Available Epigenetic information can be passed on from one generation to another via DNA methylation, histone modifications and changes in small RNAs, a process called epigenetic memory. During a mammal’s lifecycle epigenetic reprogramming, or the resetting of most epigenetic marks, occurs twice. The first instance of reprogramming occurs in primordial germ cells and the second occurs following fertilization. These processes may be both passive and active. In order for epigenetic inheritance to occur the epigenetic modifications must be able to escape reprogramming. There are several examples supporting this non-Mendelian mechanism of inheritance including the prepacking of early developmental genes in histones instead of protamines in sperm, genomic imprinting via methylation marks, the retention of CenH3 in mammalian sperm and the inheritance of piwi-associated interfering RNAs. The ability of mammals to pass on epigenetic information to their progeny provides clear evidence that inheritance is not restricted to DNA sequence and epigenetics plays a key role in producing viable offspring.

Epigenetic mechanisms in experience-driven memory formation and behavior

Science.gov (United States)

Puckett, Rosemary E; Lubin, Farah D

2011-01-01

Epigenetic mechanisms have long been associated with the regulation of gene-expression changes accompanying normal neuronal development and cellular differentiation; however, until recently these mechanisms were believed to be statically quiet in the adult brain. Behavioral neuroscientists have now begun to investigate these epigenetic mechanisms as potential regulators of gene-transcription changes in the CNS subserving synaptic plasticity and long-term memory (LTM) formation. Experimental evidence from learning and memory animal models has demonstrated that active chromatin remodeling occurs in terminally differentiated postmitotic neurons, suggesting that these molecular processes are indeed intimately involved in several stages of LTM formation, including consolidation, reconsolidation and extinction. Such chromatin modifications include the phosphorylation, acetylation and methylation of histone proteins and the methylation of associated DNA to subsequently affect transcriptional gene readout triggered by learning. The present article examines how such learning-induced epigenetic changes contribute to LTM formation and influence behavior. In particular, this article is a survey of the specific epigenetic mechanisms that have been demonstrated to regulate gene expression for both transcription factors and growth factors in the CNS, which are critical for LTM formation and storage, as well as how aberrant epigenetic processing can contribute to psychological states such as schizophrenia and drug addiction. Together, the findings highlighted in this article support a novel role for epigenetic mechanisms in the adult CNS serving as potential key molecular regulators of gene-transcription changes necessary for LTM formation and adult behavior. PMID:22126252

Epigenetics: ambiguities and implications.

Science.gov (United States)

Stotz, Karola; Griffiths, Paul

2016-12-01

Everyone has heard of 'epigenetics', but the term means different things to different researchers. Four important contemporary meanings are outlined in this paper. Epigenetics in its various senses has implications for development, heredity, and evolution, and also for medicine. Concerning development, it cements the vision of a reactive genome strongly coupled to its environment. Concerning heredity, both narrowly epigenetic and broader 'exogenetic' systems of inheritance play important roles in the construction of phenotypes. A thoroughly epigenetic model of development and evolution was Waddington's aim when he introduced the term 'epigenetics' in the 1940s, but it has taken the modern development of molecular epigenetics to realize this aim. In the final sections of the paper we briefly outline some further implications of epigenetics for medicine and for the nature/nurture debate.

Epigenetic Modifications of Major Depressive Disorder

Directory of Open Access Journals (Sweden)

Kathleen Saavedra

2016-08-01

Full Text Available Major depressive disorder (MDD is a chronic disease whose neurological basis and pathophysiology remain poorly understood. Initially, it was proposed that genetic variations were responsible for the development of this disease. Nevertheless, several studies within the last decade have provided evidence suggesting that environmental factors play an important role in MDD pathophysiology. Alterations in epigenetics mechanism, such as DNA methylation, histone modification and microRNA expression could favor MDD advance in response to stressful experiences and environmental factors. The aim of this review is to describe genetic alterations, and particularly altered epigenetic mechanisms, that could be determinants for MDD progress, and how these alterations may arise as useful screening, diagnosis and treatment monitoring biomarkers of depressive disorders.

Epigenetic considerations in aquaculture

Directory of Open Access Journals (Sweden)

Mackenzie R. Gavery

2017-12-01

Full Text Available Epigenetics has attracted considerable attention with respect to its potential value in many areas of agricultural production, particularly under conditions where the environment can be manipulated or natural variation exists. Here we introduce key concepts and definitions of epigenetic mechanisms, including DNA methylation, histone modifications and non-coding RNA, review the current understanding of epigenetics in both fish and shellfish, and propose key areas of aquaculture where epigenetics could be applied. The first key area is environmental manipulation, where the intention is to induce an ‘epigenetic memory’ either within or between generations to produce a desired phenotype. The second key area is epigenetic selection, which, alone or combined with genetic selection, may increase the reliability of producing animals with desired phenotypes. Based on aspects of life history and husbandry practices in aquaculture species, the application of epigenetic knowledge could significantly affect the productivity and sustainability of aquaculture practices. Conversely, clarifying the role of epigenetic mechanisms in aquaculture species may upend traditional assumptions about selection practices. Ultimately, there are still many unanswered questions regarding how epigenetic mechanisms might be leveraged in aquaculture.

Epigenetics and cancer

DEFF Research Database (Denmark)

Lund, Anders H; van Lohuizen, Maarten

2004-01-01

Epigenetic mechanisms act to change the accessibility of chromatin to transcriptional regulation locally and globally via modifications of the DNA and by modification or rearrangement of nucleosomes. Epigenetic gene regulation collaborates with genetic alterations in cancer development. This is e......Epigenetic mechanisms act to change the accessibility of chromatin to transcriptional regulation locally and globally via modifications of the DNA and by modification or rearrangement of nucleosomes. Epigenetic gene regulation collaborates with genetic alterations in cancer development....... This is evident from every aspect of tumor biology including cell growth and differentiation, cell cycle control, DNA repair, angiogenesis, migration, and evasion of host immunosurveillance. In contrast to genetic cancer causes, the possibility of reversing epigenetic codes may provide new targets for therapeutic...

Senescence-associated heterochromatin foci are dispensable for cellular senescence, occur in a cell type- and insult-dependent manner, and follow expression of p16 (ink4a)

Czech Academy of Sciences Publication Activity Database

Košař, Martin; Bartkova, J.; Hubáčková, Soňa; Hodný, Zdeněk; Lukas, J.; Bartek, Jiří

2011-01-01

Roč. 10, č. 3 (2011), s. 457-468 ISSN 1538-4101 R&D Projects: GA ČR GA204/08/1418; GA ČR GA301/08/0353 Institutional research plan: CEZ:AV0Z50520514 Keywords : genotoxic and replicative stress * senescence-associated heterochromatin foci * DNA damage response Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.359, year: 2011

[Nutritional epigenetics and epigenetic effects of human breast milk].

Science.gov (United States)

Lukoyanova, O L; Borovik, T E

The article provides an overview of the current literature on nutritional epigenetics. There are currently actively studied hypothesis that nutrition especially in early life or in critical periods of the development, may have a role in modulating gene expression, and, therefore, have later effects on health in adults. Nutritional epigenetics concerns knowledge about the possible effects of nutrients on gene expression. Human breast milk is well-known for its ability in preventing necrotizing enterocolitis, infectious diseases, and also non-communicable diseases, such as obesity and related disorders. This paper discusses about presumed epigenetic effects of human breast milk and some its components. While evidence suggests that a direct relationship may exist of some components of human breast milk with epigenetic changes, the mechanisms involved are stillunclear.

A community survey on knowledge of the impact of environmental and epigenetic factors on health and disease.

Science.gov (United States)

Miller, Marian; Bailey, Banita; Govindarajah, Vinothini; Levin, Linda; Metzger, Traci; Pinney, Susan M; Leung, Yuet-Kin; Ho, Shuk-Mei

2016-11-01

An outreach effort was designed to survey breast cancer survivors, supporters and their families and friends with respect to their interest in, and knowledge of, the potential impact of the environment and epigenetics on health. Two nearly identical questionnaires (one for adolescents and one for adults) were designed to gauge the perception of this community as to whether the environment impacts health and cancer risk through processes other than genetics. The questionnaires were filled out at casual social gatherings, fundraisers and wellness campaigns as well as in schools (730 participants). The differences among correct (scientific consensus) versus other responses (incorrect and not known) were evaluated. Each answer was first analysed individually and then grouped into one of three categories (diet, inheritance and environment) with age, race and gender. Differences for each response, question or group were compared by repeated measures analysis of variance. Respondents generally acknowledged that many factors could be associated with breast cancer although answers to key questions related to epigenetics based on diet, inheritance and environment were often incorrect or not known. The adult participants tended to answer more questions correctly than adolescents did. The majority of participants preferred the Internet as a major source for obtaining further information. The growing awareness and educational needs for adolescents may bring new paradigm-related environmental risk factors, which may minimise negative epigenetic outcome in subsequent generations. There is an educational opportunity, especially using electronic media, for public education concerning the impact of the environment on human health. © Royal Society for Public Health 2016.

Environmental Epigenetics: Crossroad between Public Health, Lifestyle, and Cancer Prevention

Science.gov (United States)

Romani, Massimo; Pistillo, Maria Pia; Banelli, Barbara

2015-01-01

Epigenetics provides the key to transform the genetic information into phenotype and because of its reversibility it is considered an ideal target for therapeutic interventions. This paper reviews the basic mechanisms of epigenetic control: DNA methylation, histone modifications, chromatin remodeling, and ncRNA expression and their role in disease development. We describe also the influence of the environment, lifestyle, nutritional habits, and the psychological influence on epigenetic marks and how these factors are related to cancer and other diseases development. Finally we discuss the potential use of natural epigenetic modifiers in the chemoprevention of cancer to link together public health, environment, and lifestyle. PMID:26339624

The role of epigenetics in genetic and environmental epidemiology.

Science.gov (United States)

Ladd-Acosta, Christine; Fallin, M Daniele

2016-02-01

Epidemiology is the branch of science that investigates the causes and distribution of disease in populations in order to provide preventative measures and promote human health. The fields of genetic and environmental epidemiology primarily seek to identify genetic and environmental risk factors for disease, respectively. Epigenetics is emerging as an important piece of molecular data to include in these studies because it can provide mechanistic insights into genetic and environmental risk factors for disease, identify potential intervention targets, provide biomarkers of exposure, illuminate gene-environment interactions and help localize disease-relevant genomic regions. Here, we describe the importance of including epigenetics in genetic and environmental epidemiology studies, provide a conceptual framework when considering epigenetic data in population-based studies and touch upon the many challenges that lie ahead.

Epigenetic modifications and diabetic nephropathy

Directory of Open Access Journals (Sweden)

Marpadga A. Reddy

2012-09-01

Full Text Available Diabetic nephropathy (DN is a major complication associated with both type 1 and type 2 diabetes, and a leading cause of end-stage renal disease. Conventional therapeutic strategies are not fully efficacious in the treatment of DN, suggesting an incomplete understanding of the gene regulation mechanisms involved in its pathogenesis. Furthermore, evidence from clinical trials has demonstrated a “metabolic memory” of prior exposure to hyperglycemia that continues to persist despite subsequent glycemic control. This remains a major challenge in the treatment of DN and other vascular complications. Epigenetic mechanisms such as DNA methylation, nucleosomal histone modifications, and noncoding RNAs control gene expression through regulation of chromatin structure and function and post-transcriptional mechanisms without altering the underlying DNA sequence. Emerging evidence indicates that multiple factors involved in the etiology of diabetes can alter epigenetic mechanisms and regulate the susceptibility to diabetes complications. Recent studies have demonstrated the involvement of histone lysine methylation in the regulation of key fibrotic and inflammatory genes related to diabetes complications including DN. Interestingly, histone lysine methylation persisted in vascular cells even after withdrawal from the diabetic milieu, demonstrating a potential role of epigenetic modifications in metabolic memory. Rapid advances in high-throughput technologies in the fields of genomics and epigenomics can lead to the identification of genome-wide alterations in key epigenetic modifications in vascular and renal cells in diabetes. Altogether, these findings can lead to the identification of potential predictive biomarkers and development of novel epigenetic therapies for diabetes and its associated complications.

Epigenetic mechanisms: A possible link between autism spectrum disorders and fetal alcohol spectrum disorders.

Science.gov (United States)

Varadinova, Miroslava; Boyadjieva, Nadka

2015-12-01

The etiology of autism spectrum disorders (ASDs) still remains unclear and seems to involve a considerable overlap between polygenic, epigenetic and environmental factors. We have summarized the current understanding of the interplay between gene expression dysregulation via epigenetic modifications and the potential epigenetic impact of environmental factors in neurodevelopmental deficits. Furthermore, we discuss the scientific controversies of the relationship between prenatal exposure to alcohol and alcohol-induced epigenetic dysregulations, and gene expression alterations which are associated with disrupted neural plasticity and causal pathways for ASDs. The review of the literature suggests that a better understanding of developmental epigenetics should contribute to furthering our comprehension of the etiology and pathogenesis of ASDs and fetal alcohol spectrum disorders. Copyright © 2015 Elsevier Ltd. All rights reserved.

Epigenetic regulation in Autism spectrum disorder

Directory of Open Access Journals (Sweden)

Sraboni Chaudhury

2016-12-01

Full Text Available Autism spectrum disorder (ASD is a neurodevelopmental disorder characterized by an impaired social communication skill and often results in repetitive, stereotyped behavior which is observed in children during the first few years of life. Other characteristic of this disorder includes language disabilities, difficulties in sensory integration, lack of reciprocal interactions and in some cases, cognitive delays. One percentage of the general population is affected by ASD and is four times more common in boys than girls. There are hundreds of genes, which has been identified to be associated with ASD etiology. However it remains difficult to comprehend our understanding in defining the genetic architecture necessary for complete exposition of its pathophysiology. Seeing the complexity of the disease, it is important to adopt a multidisciplinary approach which should not only focus on the “genetics” of autism but also on epigenetics, transcriptomics, immune system disruption and environmental factors that could all impact the pathogenesis of the disease. As environmental factors also play a key role in regulating the trigger of ASD, the role of chromatin remodeling and DNA methylation has started to emerge. Such epigenetic modifications directly link molecular regulatory pathways and environmental factors, which might be able to explain some aspects of complex disorders like ASD. The present review will focus on the role of epigenetic regulation in defining the underlying cause for ASD

Epigenetic regulation leading to induced pluripotency drives cancer development in vivo

Energy Technology Data Exchange (ETDEWEB)

Ohnishi, Kotaro [Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto 606-8507 (Japan); Department of Medicine, Gifu University Graduate School of Medicine, Gifu 501-1194 (Japan); Semi, Katsunori [Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto 606-8507 (Japan); Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8507 (Japan); Yamada, Yasuhiro, E-mail: y-yamada@cira.kyoto-u.ac.jp [Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto 606-8507 (Japan); Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8507 (Japan)

2014-12-05

Highlights: • Epigenetic regulation of failed reprogramming-associated cancer cells is discussed. • Similarity between pediatric cancer and reprogramming-associated cancer is discussed. • Concept for epigenetic cancer is discussed. - Abstract: Somatic cells can be reprogrammed into induced pluripotent stem cells (iPSCs) by the transient expression of reprogramming factors. During the reprogramming process, somatic cells acquire the ability to undergo unlimited proliferation, which is also an important characteristic of cancer cells, while their underlying DNA sequence remains unchanged. Based on the characteristics shared between pluripotent stem cells and cancer cells, the potential involvement of the factors leading to reprogramming toward pluripotency in cancer development has been discussed. Recent in vivo reprogramming studies provided some clues to understanding the role of reprogramming-related epigenetic regulation in cancer development. It was shown that premature termination of the in vivo reprogramming result in the development of tumors that resemble pediatric cancers. Given that epigenetic modifications play a central role during reprogramming, failed reprogramming-associated cancer development may have provided a proof of concept for epigenetics-driven cancer development in vivo.

Epigenetic regulation leading to induced pluripotency drives cancer development in vivo

International Nuclear Information System (INIS)

Ohnishi, Kotaro; Semi, Katsunori; Yamada, Yasuhiro

2014-01-01

Highlights: • Epigenetic regulation of failed reprogramming-associated cancer cells is discussed. • Similarity between pediatric cancer and reprogramming-associated cancer is discussed. • Concept for epigenetic cancer is discussed. - Abstract: Somatic cells can be reprogrammed into induced pluripotent stem cells (iPSCs) by the transient expression of reprogramming factors. During the reprogramming process, somatic cells acquire the ability to undergo unlimited proliferation, which is also an important characteristic of cancer cells, while their underlying DNA sequence remains unchanged. Based on the characteristics shared between pluripotent stem cells and cancer cells, the potential involvement of the factors leading to reprogramming toward pluripotency in cancer development has been discussed. Recent in vivo reprogramming studies provided some clues to understanding the role of reprogramming-related epigenetic regulation in cancer development. It was shown that premature termination of the in vivo reprogramming result in the development of tumors that resemble pediatric cancers. Given that epigenetic modifications play a central role during reprogramming, failed reprogramming-associated cancer development may have provided a proof of concept for epigenetics-driven cancer development in vivo

Epigenetic Influences During the Periconception Period and Assisted Reproduction.

Science.gov (United States)

Amoako, Akwasi A; Nafee, Tamer M; Ola, Bolarinde

2017-01-01

The periconception period starts 6 months before conception and lasts until the tenth week of gestation. In this chapter, we will focus on epigenetic modifications to DNA and gene expression within this period and during assisted reproduction. There are two critical times during the periconception window when significant epigenetic 'reprogramming' occur: one during gametogenesis and another during the pre-implantation embryonic stage. Furthermore, assisted conception treatments, laboratory protocols and culture media can affect the embryo development and birth weights in laboratory animals. There is, however, an ongoing debate as to whether epigenetic changes in humans, causing embryo mal-development, placenta dysfunction and birth defects, result from assisted reproductive technologies or are consequences of pre-existing medical and/or genetic conditions in the parents. The periconception period starts from ovarian folliculogenesis, through resumption of oogenesis, fertilisation, peri-implantation embryo development, embryogenesis until the end of organogenesis. In men, it is the period from spermatogenesis to epididymal sperm storage and fertilisation. Gametes and developing embryos are sensitive to environmental factors during this period, and epigenetic modifications can occur in response to adverse lifestyles and environmental factors. We now know that lifestyle factors such as advanced parentage age, obesity or undernutrition, smoking, excessive alcohol and caffeine intake and recreational drugs used during gamete production and embryogenesis could induce epigenetic alterations, which could impact adversely on pregnancy outcomes and health of the offspring. Furthermore, these can also result in a permanent and irreversible effect in a dose-dependent manner, which can be passed on to the future generations.

Epigenetics in Alzheimer's Disease: Perspective of DNA Methylation.

Science.gov (United States)

Qazi, Talal Jamil; Quan, Zhenzhen; Mir, Asif; Qing, Hong

2018-02-01

Research over the years has shown that causes of Alzheimer's disease are not well understood, but over the past years, the involvement of epigenetic mechanisms in the developing memory formation either under pathological or physiological conditions has become clear. The term epigenetics represents the heredity of changes in phenotype that are independent of altered DNA sequences. Different studies validated that cytosine methylation of genomic DNA decreases with age in different tissues of mammals, and therefore, the role of epigenetic factors in developing neurological disorders in aging has been under focus. In this review, we summarized and reviewed the involvement of different epigenetic mechanisms especially the DNA methylation in Alzheimer's disease (AD), late-onset Alzheimer's disease (LOAD), familial Alzheimer's disease (FAD), and autosomal dominant Alzheimer's disease (ADAD). Down to the minutest of details, we tried to discuss the methylation patterns like mitochondrial DNA methylation and ribosomal DNA (rDNA) methylation. Additionally, we mentioned some therapeutic approaches related to epigenetics, which could provide a potential cure for AD. Moreover, we reviewed some recent studies that validate DNA methylation as a potential biomarker and its role in AD. We hope that this review will provide new insights into the understanding of AD pathogenesis from the epigenetic perspective especially from the perspective of DNA methylation.

Age-specific epigenetic drift in late-onset Alzheimer's disease.

Directory of Open Access Journals (Sweden)

Sun-Chong Wang

Full Text Available Despite an enormous research effort, most cases of late-onset Alzheimer's disease (LOAD still remain unexplained and the current biomedical science is still a long way from the ultimate goal of revealing clear risk factors that can help in the diagnosis, prevention and treatment of the disease. Current theories about the development of LOAD hinge on the premise that Alzheimer's arises mainly from heritable causes. Yet, the complex, non-Mendelian disease etiology suggests that an epigenetic component could be involved. Using MALDI-TOF mass spectrometry in post-mortem brain samples and lymphocytes, we have performed an analysis of DNA methylation across 12 potential Alzheimer's susceptibility loci. In the LOAD brain samples we identified a notably age-specific epigenetic drift, supporting a potential role of epigenetic effects in the development of the disease. Additionally, we found that some genes that participate in amyloid-beta processing (PSEN1, APOE and methylation homeostasis (MTHFR, DNMT1 show a significant interindividual epigenetic variability, which may contribute to LOAD predisposition. The APOE gene was found to be of bimodal structure, with a hypomethylated CpG-poor promoter and a fully methylated 3'-CpG-island, that contains the sequences for the epsilon4-haplotype, which is the only undisputed genetic risk factor for LOAD. Aberrant epigenetic control in this CpG-island may contribute to LOAD pathology. We propose that epigenetic drift is likely to be a substantial mechanism predisposing individuals to LOAD and contributing to the course of disease.

Heterochromatin analysis in the fish species Liposarcus anisitsi (siluriformes and Leporinus elongatus (characiformes

Directory of Open Access Journals (Sweden)

Roberto Ferreira Artoni

1999-03-01

Full Text Available The chromosomes of two neotropical freshwater fish species, namely Liposarcus anisitsi (Siluriformes, Loricariidae and Leporinus elongatus (Characiformes, Anostomidae, were investigated by means of C-banding, Ag-NORs, fluorochrome staining and banding by hot saline solution (HSS treatment, to reveal patterns of heterochromatin differentiation. The karyotype of L. anisitsi is described for the first time. Staining with the GC-specific fluorescent antibiotic mithramycin (MM revealed bright signals in some C-banded blocks in both species, suggesting that these MM+ heterochromatin contains GC-rich DNA. Banding by denaturation employing HSS, followed by Giemsa staining, yielded corresponding results documenting the thermal stability of GC-rich DNA part of heterochromatin positive after C-banding. In L. elongatus the Ag-NOR also followed the above banding patterns. However, in L. anisitsi the Ag-NOR was MM+ but negatively stained after C-banding and HSS treatment. L. elongatus also showed C-banded segments that were negative for mithramycin staining and HSS treatment. The results obtained evidence the heterochromatin heterogeneity in these fish species.Cromossomos mitóticos de duas especies de peixes neotropicais, Leporinus elongatus (Characiformes e Liposarcus anisitsi (Siluriformes, foram estudados por diferentes métodos de bandamentos, com o intuito de investigar a diferenciação da heterocromatina. Enquanto que a macroestrutura cariotípica de L. elongatus já foi objeto de estudos anteriores, o cariótipo de L. anisitsi está sendo apresentado pela primeira vez. Em ambas as espécies, a coloração dos cromossomos com a mitramicina (MM, fluorocromo GC específico, evidenciou sinais brilhantes em alguns segmentos heterocromáticos também positivos ao bandamento C, sugerindo ser esta fração da heterocromatina rica em seqüências de bases GC. O tratamento dos cromossomos com solução salina aquecida e posterior coloração com Giemsa

Epigenetics and Vasculitis: a Comprehensive Review.

Science.gov (United States)

Renauer, Paul; Coit, Patrick; Sawalha, Amr H

2016-06-01

Vasculitides represent a group of relatively rare systemic inflammatory diseases of the blood vessels. Despite recent progress in understanding the genetic basis and the underlying pathogenic mechanisms in vasculitis, the etiology and pathogenesis of vasculitis remain incompletely understood. Epigenetic dysregulation plays an important role in immune-mediated diseases, and the contribution of epigenetic aberrancies in vasculitis is increasingly being recognized. Histone modifications in the PR3 and MPO gene loci might be mechanistically involved in the pathogenesis of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Similarly, other studies revealed important epigenetic contribution to other vasculitides, including Kawasaki disease and IgA vasculitis. More recently, genome-wide epigenomic studies have been performed in several vasculitides. A recent genome-wide DNA methylation study uncovered an important role for epigenetic remodeling of cytoskeleton-related genes in the pathogenesis of Behçet's disease and suggested that reversal of some of these DNA methylation changes associates with disease remission. Genome-wide DNA methylation profiling characterized the inflammatory response in temporal artery tissue from patients with giant cell arteritis and showed increased activation of calcineurin/nuclear factor of activated T cells (NFAT) signaling, prompting the suggestion that a specific calcineurin/NFAT inhibitor that is well tolerated and with the added beneficial anti-platelet activity, such as dipyridamole, might be of therapeutic potential in giant cell arteritis. While epigenetic studies in systemic vasculitis are still in their infancy, currently available data clearly indicate that investigating the epigenetic mechanisms underlying these diseases will help to better understand the pathogenesis of vasculitis and provide novel targets for the development of disease biomarkers and new therapies.

A specific PfEMP1 is expressed in P. falciparum sporozoites and plays a role in hepatocyte infection

DEFF Research Database (Denmark)

Zanghì, Gigliola; Vembar, Shruthi S; Baumgarten, Sebastian

2018-01-01

Heterochromatin plays a central role in the process of immune evasion, pathogenesis, and transmission of the malaria parasite Plasmodium falciparum during blood stage infection. Here, we use ChIP sequencing to demonstrate that sporozoites from mosquito salivary glands expand heterochromatin......_SpzPfEMP1. Overall, we show that the epigenetic signature of var genes is reset in mosquito stages. Moreover, the identification of a strain-specific sporozoite PfEMP1 is highly relevant for vaccine design based on sporozoites....

Molecular targets of epigenetic regulation and effectors of environmental influences

International Nuclear Information System (INIS)

Choudhuri, Supratim; Cui Yue; Klaassen, Curtis D.

2010-01-01

The true understanding of what we currently define as epigenetics evolved over time as our knowledge on DNA methylation and chromatin modifications and their effects on gene expression increased. The current explosion of research on epigenetics and the increasing documentation of the effects of various environmental factors on DNA methylation, chromatin modification, as well as on the expression of small non-coding RNAs (ncRNAs) have expanded the scope of research on the etiology of various diseases including cancer. The current review briefly discusses the molecular mechanisms of epigenetic regulation and expands the discussion with examples on the role of environment, such as the immediate environment during development, in inducing epigenetic changes and modulating gene expression.

Epigenetic regulation of axon and dendrite growth

Directory of Open Access Journals (Sweden)

Ephraim F Trakhtenberg

2012-03-01

Full Text Available Neuroregenerative therapies for central nervous system (CNS injury, neurodegenerative disease, or stroke require axons of damaged neurons to grow and reinnervate their targets. However, mature mammalian CNS neurons do not regenerate their axons, limiting recovery in these diseases (Yiu and He, 2006. CNS’ regenerative failure may be attributable to the development of an inhibitory CNS environment by glial-associated inhibitory molecules (Yiu and He, 2006, and by various cell-autonomous factors (Sun and He, 2010. Intrinsic axon growth ability also declines developmentally (Li et al., 1995; Goldberg et al., 2002; Bouslama-Oueghlani et al., 2003; Blackmore and Letourneau, 2006 and is dependent on transcription (Moore et al., 2009. Although neurons’ intrinsic capacity for axon growth may depend in part on the panoply of expressed transcription factors (Moore and Goldberg, 2011, epigenetic factors such as the accessibility of DNA and organization of chromatin are required for downstream genes to be transcribed. Thus a potential approach to overcoming regenerative failure focuses on the epigenetic mechanisms regulating regenerative gene expression in the CNS. Here we review molecular mechanisms regulating the epigenetic state of DNA through chromatin modifications, their implications for regulating axon and dendrite growth, and important new directions for this field of study.

Nutritional epigenetics

Science.gov (United States)

This chapter is intended to provide a timely overview of the current state of research at the intersection of nutrition and epigenetics. I begin by describing epigenetics and molecular mechanisms of eigenetic regulation, then highlight four classes of nutritional exposures currently being investiga...

Measuring topology of low-intensity DNA methylation sites for high-throughput assessment of epigenetic drug-induced effects in cancer cells

International Nuclear Information System (INIS)

Gertych, Arkadiusz; Farkas, Daniel L.; Tajbakhsh, Jian

2010-01-01

Epigenetic anti-cancer drugs with demethylating effects have shown to alter genome organization in mammalian cell nuclei. The interest in the development of novel epigenetic drugs has increased the demand for cell-based assays to evaluate drug performance in pre-clinical studies. An imaging-based cytometrical approach that can measure demethylation effects as changes in the spatial nuclear distributions of methylated cytosine and global DNA in cancer cells is introduced in this paper. The cells were studied by immunofluorescence with a specific antibody against 5-methylcytosine (MeC), and 4,6-diamidino-2-phenylindole (DAPI) for delineation of methylated sites and global DNA in nuclei. In the preprocessing step the segmentation of nuclei in three-dimensional images (3-D) is followed by an automated assessment of nuclear DAPI/MeC patterns to exclude dissimilar entities. Next, low-intensity MeC (LIM) and low-intensity DNA (LID) sites of similar nuclei are localized and processed to obtain specific nuclear density profiles. These profiles sampled at half of the total nuclear volume yielded two parameters: LIM 0.5 and LID 0.5 . The analysis shows that zebularine and 5-azacytidine-the two tested epigenetic drugs introduce changes in the spatial distribution of low-intensity DNA and MeC signals. LIM 0.5 and LID 0.5 were significantly different (p < 0.001) in 5-azacytidine treated (n = 660) and zebularine treated (n = 496) vs. untreated (n = 649) DU145 human prostate cancer cells. In the latter case the LIM sites were predominantly found at the nuclear border, whereas treated populations showed different degrees of increase in LIMs towards the interior nuclear space, in which a large portion of heterochromatin is located. The cell-by-cell evaluation of changes in the spatial reorganization of MeC/DAPI signals revealed that zebularine is a more gentle demethylating agent than 5-azacytidine. Measuring changes in the topology of low-intensity sites can potentially be a

Gene X Environment Interactions in Autism Spectrum Disorders: Role of Epigenetic Mechanisms

Directory of Open Access Journals (Sweden)

Sylvie eTordjman

2014-08-01

Full Text Available Several studies support currently the hypothesis that autism etiology is based on a polygenic and epistatic model. However, despite advances in epidemiological, molecular and clinical genetics, the genetic risk factors remain difficult to identify, with the exception of a few chromosomal disorders and several single gene disorders associated with an increased risk for autism. Furthermore, several studies suggest a role of environmental factors in autism spectrum disorders (ASD. First, arguments for a genetic contribution to autism, based on updated family and twin studies, are examined. Second, a review of possible prenatal, perinatal and postnatal environmental risk factors for ASD are presented. Then, the hypotheses are discussed concerning the underlying mechanisms related to a role of environmental factors in the development of ASD in association with genetic factors. In particular, epigenetics as a candidate biological mechanism for gene X environment interactions is considered and the possible role of epigenetic mechanisms reported in genetic disorders associated with ASD is discussed. Furthermore, the example of in utero exposure to valproate provides a good illustration of epigenetic mechanisms involved in ASD and innovative therapeutic strategies. Epigenetic remodeling by environmental factors opens new perspectives for a better understanding, prevention and early therapeutic intervention of ASD.

Epigenetic regulation of caloric restriction in aging

Directory of Open Access Journals (Sweden)

Daniel Michael

2011-08-01

Full Text Available Abstract The molecular mechanisms of aging are the subject of much research and have facilitated potential interventions to delay aging and aging-related degenerative diseases in humans. The aging process is frequently affected by environmental factors, and caloric restriction is by far the most effective and established environmental manipulation for extending lifespan in various animal models. However, the precise mechanisms by which caloric restriction affects lifespan are still not clear. Epigenetic mechanisms have recently been recognized as major contributors to nutrition-related longevity and aging control. Two primary epigenetic codes, DNA methylation and histone modification, are believed to dynamically influence chromatin structure, resulting in expression changes of relevant genes. In this review, we assess the current advances in epigenetic regulation in response to caloric restriction and how this affects cellular senescence, aging and potential extension of a healthy lifespan in humans. Enhanced understanding of the important role of epigenetics in the control of the aging process through caloric restriction may lead to clinical advances in the prevention and therapy of human aging-associated diseases.

Epigenetics and Cellular Metabolism

Directory of Open Access Journals (Sweden)

Wenyi Xu

2016-01-01

Full Text Available Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc. is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the processing of epigenetic memory. Here, we summarize the recent research progress in the epigenetic regulation of cellular metabolism and discuss how the dysfunction of epigenetic machineries influences the development of metabolic disorders such as diabetes and obesity; then, we focus on discussing the notion that manipulating metabolites, the fuel of cell metabolism, can function as a strategy for interfering epigenetic machinery and its related disease progression as well.

Elusive inheritance: Transgenerational effects and epigenetic inheritance in human environmental disease.

Science.gov (United States)

Martos, Suzanne N; Tang, Wan-Yee; Wang, Zhibin

2015-07-01

Epigenetic mechanisms involving DNA methylation, histone modification, histone variants and nucleosome positioning, and noncoding RNAs regulate cell-, tissue-, and developmental stage-specific gene expression by influencing chromatin structure and modulating interactions between proteins and DNA. Epigenetic marks are mitotically inherited in somatic cells and may be altered in response to internal and external stimuli. The idea that environment-induced epigenetic changes in mammals could be inherited through the germline, independent of genetic mechanisms, has stimulated much debate. Many experimental models have been designed to interrogate the possibility of transgenerational epigenetic inheritance and provide insight into how environmental exposures influence phenotypes over multiple generations in the absence of any apparent genetic mutation. Unexpected molecular evidence has forced us to reevaluate not only our understanding of the plasticity and heritability of epigenetic factors, but of the stability of the genome as well. Recent reviews have described the difference between transgenerational and intergenerational effects; the two major epigenetic reprogramming events in the mammalian lifecycle; these two events making transgenerational epigenetic inheritance of environment-induced perturbations rare, if at all possible, in mammals; and mechanisms of transgenerational epigenetic inheritance in non-mammalian eukaryotic organisms. This paper briefly introduces these topics and mainly focuses on (1) transgenerational phenotypes and epigenetic effects in mammals, (2) environment-induced intergenerational epigenetic effects, and (3) the inherent difficulties in establishing a role for epigenetic inheritance in human environmental disease. Copyright © 2015 Elsevier Ltd. All rights reserved.

Karyotype, heterochromatin distribution and meiosis of Zabrotes subfasciatus (Bohemann) (Coleoptera: Chrysomelidae, Bruchinae)

International Nuclear Information System (INIS)

Correa, Ronan X.; Santos, Igor S.; Silva, Janisete G.; Costa, Marco A.; Pompolo, Silvia G.

2008-01-01

Zabrotes subfasciatus (Boh.) has been extensively studied in its agronomic and biochemical aspects due to its importance as a damaging insect to leguminous grains during storage. The few cytogenetic studies published on this species yielded conflicting results. In this study, the karyotype was analyzed in order to accurately describe the chromosome C-banding patterns and meiosis. The brain ganglion at the pre pupa and the adult and pupal testes were analyzed. All individuals had 26 chromosomes in both brain ganglion and spermatogonic mitotic metaphases. These chromosomes were classified as follows: the 12 th pair and the Y chromosome were telocentric; the X chromosome was acrocentric; the 4 th and 5 th pairs were sub metacentric; and the remaining pairs were all metacentric. One of the members of the 5 th pair presented a secondary constriction. All chromosomes presented pericentromeric heterochromatin. The large arms of the pairs 5, 9 and X presented heterochromatin. The X chromosome showed to be heteropyknotic throughout the prophase of the fi rst meiotic division. The sub phases of prophase I were atypical and meiosis II was rarely identified. Testes of all males showed a few cells; the bivalents were rod-like shaped in metaphase I. Karyological formulae were 2n = 24 + XX in females and 2n = 24 + XYp and either n = 12 + X or n = 12 + Y in males. (author)

Karyotype, heterochromatin distribution and meiosis of Zabrotes subfasciatus (Bohemann) (Coleoptera: Chrysomelidae, Bruchinae)

Energy Technology Data Exchange (ETDEWEB)

Correa, Ronan X.; Santos, Igor S.; Silva, Janisete G.; Costa, Marco A. [Universidade Estadual de Santa Cruz, Ilheus, BA (Brazil). Dept. de Ciencias Biologicas; Pompolo, Silvia G. [Universidade Federal de Vicosa, MG (Brazil). Dept. de Biologia Geral

2008-09-15

Zabrotes subfasciatus (Boh.) has been extensively studied in its agronomic and biochemical aspects due to its importance as a damaging insect to leguminous grains during storage. The few cytogenetic studies published on this species yielded conflicting results. In this study, the karyotype was analyzed in order to accurately describe the chromosome C-banding patterns and meiosis. The brain ganglion at the pre pupa and the adult and pupal testes were analyzed. All individuals had 26 chromosomes in both brain ganglion and spermatogonic mitotic metaphases. These chromosomes were classified as follows: the 12{sup th} pair and the Y chromosome were telocentric; the X chromosome was acrocentric; the 4{sup th} and 5{sup th} pairs were sub metacentric; and the remaining pairs were all metacentric. One of the members of the 5{sup th} pair presented a secondary constriction. All chromosomes presented pericentromeric heterochromatin. The large arms of the pairs 5, 9 and X presented heterochromatin. The X chromosome showed to be heteropyknotic throughout the prophase of the fi rst meiotic division. The sub phases of prophase I were atypical and meiosis II was rarely identified. Testes of all males showed a few cells; the bivalents were rod-like shaped in metaphase I. Karyological formulae were 2n = 24 + XX in females and 2n = 24 + XYp and either n = 12 + X or n = 12 + Y in males. (author)

Epigenetic Heterogeneity of B-Cell Lymphoma: Chromatin Modifiers

Science.gov (United States)

Hopp, Lydia; Nersisyan, Lilit; Löffler-Wirth, Henry; Arakelyan, Arsen; Binder, Hans

2015-01-01

We systematically studied the expression of more than fifty histone and DNA (de)methylating enzymes in lymphoma and healthy controls. As a main result, we found that the expression levels of nearly all enzymes become markedly disturbed in lymphoma, suggesting deregulation of large parts of the epigenetic machinery. We discuss the effect of DNA promoter methylation and of transcriptional activity in the context of mutated epigenetic modifiers such as EZH2 and MLL2. As another mechanism, we studied the coupling between the energy metabolism and epigenetics via metabolites that act as cofactors of JmjC-type demethylases. Our study results suggest that Burkitt’s lymphoma and diffuse large B-cell Lymphoma differ by an imbalance of repressive and poised promoters, which is governed predominantly by the activity of methyltransferases and the underrepresentation of demethylases in this regulation. The data further suggest that coupling of epigenetics with the energy metabolism can also be an important factor in lymphomagenesis in the absence of direct mutations of genes in metabolic pathways. Understanding of epigenetic deregulation in lymphoma and possibly in cancers in general must go beyond simple schemes using only a few modes of regulation. PMID:26506391

Epigenetic Heterogeneity of B-Cell Lymphoma: Chromatin Modifiers

Directory of Open Access Journals (Sweden)

Lydia Hopp

2015-10-01

Full Text Available We systematically studied the expression of more than fifty histone and DNA (demethylating enzymes in lymphoma and healthy controls. As a main result, we found that the expression levels of nearly all enzymes become markedly disturbed in lymphoma, suggesting deregulation of large parts of the epigenetic machinery. We discuss the effect of DNA promoter methylation and of transcriptional activity in the context of mutated epigenetic modifiers such as EZH2 and MLL2. As another mechanism, we studied the coupling between the energy metabolism and epigenetics via metabolites that act as cofactors of JmjC-type demethylases. Our study results suggest that Burkitt’s lymphoma and diffuse large B-cell Lymphoma differ by an imbalance of repressive and poised promoters, which is governed predominantly by the activity of methyltransferases and the underrepresentation of demethylases in this regulation. The data further suggest that coupling of epigenetics with the energy metabolism can also be an important factor in lymphomagenesis in the absence of direct mutations of genes in metabolic pathways. Understanding of epigenetic deregulation in lymphoma and possibly in cancers in general must go beyond simple schemes using only a few modes of regulation.

Clinical implications of epigenetic regulation in oral cancer.

Science.gov (United States)

D'Souza, Wendy; Saranath, Dhananjaya

2015-12-01

Oral cancer is a high incidence cancer which is of major public health concern in India being the most common cancer in males and fifth most common cancer in females in India, contributing to 26% of the global oral cancer burden. The major risk factors of oral cancer are tobacco, alcohol and high risk Human Papilloma Virus type 16/18. However, only 3-12% of the high risk individuals with dysplasia develop oral cancer. Thus, individual genomic variants representing the genomic constitution and epigenetic alterations play a critical role in the development of oral cancer. Extensive epigenetic studies on the molecular lesions including oncogenes, tumor suppressor genes, genes associated with apoptosis, DNA damage repair have been reported. The current review highlights epigenetic regulation with a focus on molecular biomarkers and epidrug therapy in oral cancer. Epigenetic regulation by hypermethylation, histone modifications and specific microRNAs are often associated with early events and advanced stages in oral cancer, and thus indicate epidrug therapy for intervention. The presence of epigenetic marks in oral lesions, cancers and tumor associated mucosa emphasizes indications as biomarkers and epidrugs with therapeutic potential for better patient management. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Real Culprit in Systemic Lupus Erythematosus: Abnormal Epigenetic Regulation

Science.gov (United States)

Wu, Haijing; Zhao, Ming; Chang, Christopher; Lu, Qianjin

2015-01-01

Systemic lupus erythematosus (SLE) is an autoimmune disease involving multiple organs and the presence of anti-nuclear antibodies. The pathogenesis of SLE has been intensively studied but remains far from clear. B and T lymphocyte abnormalities, dysregulation of apoptosis, defects in the clearance of apoptotic materials, and various genetic and epigenetic factors are attributed to the development of SLE. The latest research findings point to the association between abnormal epigenetic regulation and SLE, which has attracted considerable interest worldwide. It is the purpose of this review to present and discuss the relationship between aberrant epigenetic regulation and SLE, including DNA methylation, histone modifications and microRNAs in patients with SLE, the possible mechanisms of immune dysfunction caused by epigenetic changes, and to better understand the roles of aberrant epigenetic regulation in the initiation and development of SLE and to provide an insight into the related therapeutic options in SLE. PMID:25988383

Epigenetics: beyond genes

CSIR Research Space (South Africa)

Fossey, A

2009-06-01

Full Text Available in forestry breeding. Keywords Gene regulation; chromatin; histone code hyporthesis; RNA silencing; post transcriptional gene silencing; forestry. Introduction to epigenetic phenomena Most living organisms share a vast amount of genetic information... (Rapp and Wendel, 2005). Epigenetic phenomena pervade all aspects of cell proliferation and plant development and are often in conflict with Mendelian models of genetics (Grant-Downton and Dickinson, 2005). A key element in many epigenetic effects...

Epigenetics and obesity

OpenAIRE

Stöger, Reinhard

2008-01-01

Common DNA sequence variants inadequately explain variability in fat mass among individuals. Abnormal body weights are characteristic of specific imprinted-gene disorders. However, the relevance of imprinted genes to our understanding of obesity among the general population is uncertain. Hitherto unidentified imprinted genes and epigenetic mosaicism are two of the challenges for this emerging field of epigenetics. Subtle epigenetic differences in imprinted genes and gene networks are likely t...

The Interaction between the Immune System and Epigenetics in the Etiology of Autism Spectrum Disorders.

Science.gov (United States)

Nardone, Stefano; Elliott, Evan

2016-01-01

Recent studies have firmly established that the etiology of autism includes both genetic and environmental components. However, we are only just beginning to elucidate the environmental factors that might be involved in the development of autism, as well as the molecular mechanisms through which they function. Mounting epidemiological and biological evidence suggest that prenatal factors that induce a more activated immune state in the mother are involved in the development of autism. In parallel, molecular studies have highlighted the role of epigenetics in brain development as a process susceptible to environmental influences and potentially causative of autism spectrum disorders (ASD). In this review, we will discuss converging evidence for a multidirectional interaction between immune system activation in the mother during pregnancy and epigenetic regulation in the brain of the fetus that may cooperate to produce an autistic phenotype. This interaction includes immune factor-induced changes in epigenetic signatures in the brain, dysregulation of epigenetic modifications specifically in genomic regions that encode immune functions, and aberrant epigenetic regulation of microglia. Overall, the interaction between immune system activation in the mother and the subsequent epigenetic dysregulation in the developing fetal brain may be a main consideration for the environmental factors that cause autism.

The interaction between the immune system and epigenetics in the etiology of autism spectrum disorders

Directory of Open Access Journals (Sweden)

Stefano Nardone

2016-07-01

Full Text Available Recent studies have firmly established that the etiology of autism includes both genetic and environmental components. However, we are only just beginning to elucidate the environmental factors that might be involved in the development of autism, as well as the molecular mechanisms through which they function. Mounting epidemiological and biological evidence suggest that prenatal factors that induce a more activated immune state in the mother are involved in the development of autism. In parallel, molecular studies have highlighted the role of epigenetics in brain development as process susceptible to environmental influences and potentially causative of ASD. In this review, we will discuss converging evidence for a multidirectional interaction between immune system activation in the mother during pregnancy and epigenetic regulation in the brain of the fetus that may cooperate to produce an autistic phenotype. This interaction includes immune factor-induced changes in epigenetic signatures in the brain, dysregulation of epigenetic modifications specifically in genomic regions that encode immune functions, and aberrant epigenetic regulation of microglia. Overall, the interaction between immune system activation in the mother and the subsequent epigenetic dysregulation in the developing fetal brain may be a main consideration for the environmental factors that cause autism.

Epigenetic changes in neurology: DNA methylation in multiple sclerosis.

Science.gov (United States)

Iridoy Zulet, M; Pulido Fontes, L; Ayuso Blanco, T; Lacruz Bescos, F; Mendioroz Iriarte, M

2017-09-01

Epigenetics is defined as the study of the mechanisms that regulate gene expression without altering the underlying DNA sequence. The best known is DNA methylation. Multiple Sclerosis (MS) is a disease with no entirely known etiology, in which it is stated that the involvement of environmental factors on people with a genetic predisposition, may be key to the development of the disease. It is at this intersection between genetic predisposition and environmental factors where DNA methylation may play a pathogenic role. A literature review of the effects of environmental risk factors for the development of MS can have on the different epigenetic mechanisms as well as the implication that such changes have on the development of the disease. Knowledge of epigenetic modifications involved in the pathogenesis of MS, opens a new avenue of research for identification of potential biomarkers, as well as finding new therapeutic targets. Copyright © 2015 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

Differentiation-independent fluctuation of pluripotency-related transcription factors and other epigenetic markers in embryonic stem cell colonies

Czech Academy of Sciences Publication Activity Database

Šustáčková, Gabriela; Legartová, Soňa; Kozubek, Stanislav; Stixová, Lenka; Pacherník, J.; Bártová, Eva

2012-01-01

Roč. 21, č. 5 (2012), s. 710-720 ISSN 1547-3287 R&D Projects: GA MŠk(CZ) LC535; GA MŠk(CZ) LC06027; GA MŠk(CZ) ME 919; GA ČR(CZ) GAP302/10/1022 Institutional research plan: CEZ:AV0Z50040507 Keywords : ES cells * epigenetics * Oct4 Subject RIV: BO - Biophysics Impact factor: 4.670, year: 2012

Mitochondrial regulation of epigenetics and its role in human diseases

DEFF Research Database (Denmark)

Minocherhomji, Sheroy; Tollefsbol, Trygve O; Singh, Keshav K

2012-01-01

as the sole pathogenic factor suggesting that additional mechanisms contribute to lack of genotype and clinical phenotype correlationship. An increasing number of studies have identified a possible effect on the epigenetic landscape of the nuclear genome as a consequence of mitochondrial dysfunction....... In particular, these studies demonstrate reversible or irreversible changes in genomic DNA methylation profiles of the nuclear genome. Here we review how mitochondria damage checkpoint (mitocheckpoint) induces epigenetic changes in the nucleus. Persistent pathogenic mutations in mtDNA may also lead...... to epigenetic changes causing genomic instability in the nuclear genome. We propose that "mitocheckpoint" mediated epigenetic and genetic changes may play key roles in phenotypic variation related to mitochondrial diseases or host of human diseases in which mitochondrial defect plays a primary role....

Epigenetics in natural animal populations.

Science.gov (United States)

Hu, J; Barrett, R D H

2017-09-01

Phenotypic plasticity is an important mechanism for populations to buffer themselves from environmental change. While it has long been appreciated that natural populations possess genetic variation in the extent of plasticity, a surge of recent evidence suggests that epigenetic variation could also play an important role in shaping phenotypic responses. Compared with genetic variation, epigenetic variation is more likely to have higher spontaneous rates of mutation and a more sensitive reaction to environmental inputs. In our review, we first provide an overview of recent studies on epigenetically encoded thermal plasticity in animals to illustrate environmentally-mediated epigenetic effects within and across generations. Second, we discuss the role of epigenetic effects during adaptation by exploring population epigenetics in natural animal populations. Finally, we evaluate the evolutionary potential of epigenetic variation depending on its autonomy from genetic variation and its transgenerational stability. Although many of the causal links between epigenetic variation and phenotypic plasticity remain elusive, new data has explored the role of epigenetic variation in facilitating evolution in natural populations. This recent progress in ecological epigenetics will be helpful for generating predictive models of the capacity of organisms to adapt to changing climates. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

Autism Spectrum Disorders and Epigenetics

Science.gov (United States)

Grafodatskaya, Daria; Chung, Brian; Szatmari, Peter; Weksberg, Rosanna

2010-01-01

Objective: Current research suggests that the causes of autism spectrum disorders (ASD) are multifactorial and include both genetic and environmental factors. Several lines of evidence suggest that epigenetics also plays an important role in ASD etiology and that it might, in fact, integrate genetic and environmental influences to dysregulate…

Epigenetic Matters: The Link between Early Nutrition, Microbiome, and Long-term Health Development

Directory of Open Access Journals (Sweden)

Flavia Indrio

2017-08-01

Full Text Available Epigenetic modifications are among the most important mechanisms by which environmental factors can influence early cellular differentiation and create new phenotypic traits during pregnancy and within the neonatal period without altering the deoxyribonucleic acid sequence. A number of antenatal and postnatal factors, such as maternal and neonatal nutrition, pollutant exposure, and the composition of microbiota, contribute to the establishment of epigenetic changes that can not only modulate the individual adaptation to the environment but also have an influence on lifelong health and disease by modifying inflammatory molecular pathways and the immune response. Postnatal intestinal colonization, in turn determined by maternal flora, mode of delivery, early skin-to-skin contact and neonatal diet, leads to specific epigenetic signatures that can affect the barrier properties of gut mucosa and their protective role against later insults, thus potentially predisposing to the development of late-onset inflammatory diseases. The aim of this review is to outline the epigenetic mechanisms of programming and development acting within early-life stages and to examine in detail the role of maternal and neonatal nutrition, microbiota composition, and other environmental factors in determining epigenetic changes and their short- and long-term effects.

Epigenetic Matters: The Link between Early Nutrition, Microbiome, and Long-term Health Development

Science.gov (United States)

Indrio, Flavia; Martini, Silvia; Francavilla, Ruggiero; Corvaglia, Luigi; Cristofori, Fernanda; Mastrolia, Salvatore Andrea; Neu, Josef; Rautava, Samuli; Russo Spena, Giovanna; Raimondi, Francesco; Loverro, Giuseppe

2017-01-01

Epigenetic modifications are among the most important mechanisms by which environmental factors can influence early cellular differentiation and create new phenotypic traits during pregnancy and within the neonatal period without altering the deoxyribonucleic acid sequence. A number of antenatal and postnatal factors, such as maternal and neonatal nutrition, pollutant exposure, and the composition of microbiota, contribute to the establishment of epigenetic changes that can not only modulate the individual adaptation to the environment but also have an influence on lifelong health and disease by modifying inflammatory molecular pathways and the immune response. Postnatal intestinal colonization, in turn determined by maternal flora, mode of delivery, early skin-to-skin contact and neonatal diet, leads to specific epigenetic signatures that can affect the barrier properties of gut mucosa and their protective role against later insults, thus potentially predisposing to the development of late-onset inflammatory diseases. The aim of this review is to outline the epigenetic mechanisms of programming and development acting within early-life stages and to examine in detail the role of maternal and neonatal nutrition, microbiota composition, and other environmental factors in determining epigenetic changes and their short- and long-term effects. PMID:28879172

Interplay of Inflammatory Mediators with Epigenetics and Cartilage Modifications in Osteoarthritis

Directory of Open Access Journals (Sweden)

Swarna Raman

2018-03-01

Full Text Available Osteoarthritis (OA, a degenerative disease of diarthrodial joints, is influenced by mechanical and inflammatory factors with aging, obesity, chronic injuries, and secondary diseases thought to be major factors driving the process of articular cartilage degeneration. Chondrocytes, the cellular component of cartilage, reside in an avascular environment and normally have limited potential to replicate. However, extrinsic factors such as injury to the joint or intrinsic alterations to the chondrocytes themselves can lead to an altered phenotype and development of OA. Synovial inflammation is also a pivotal element of the osteoarthritic, degenerative process: influx of pro-inflammatory cytokines and production of matrix metalloproteinases accelerate advanced cellular processes such as synovitis and cartilage damage. As well as a genetic input, recent data have highlighted epigenetic factors as contributing to disease. Studies conducted over the last decade have focused on three key aspects in OA; inflammation and the immune response, genome-wide association studies that have identified important genes undergoing epigenetic modifications, and finally how chondrocytes transform in their function during development and disease. Data highlighted here have identified critical inflammatory genes involved in OA and how these factors impact chondrocyte hypertrophy in the disease. This review also addresses key inflammatory factors in synovial inflammation, epigenetics, and chondrocyte fate, and how agents that inhibit epigenetic mechanisms like DNA methylation and histone modifications could aid in development of long-term treatment strategies for the disease.

Epigenetic Mechanisms in Bone Biology and Osteoporosis: Can They Drive Therapeutic Choices?

Directory of Open Access Journals (Sweden)

Francesca Marini

2016-08-01

Full Text Available Osteoporosis is a complex multifactorial disorder of the skeleton. Genetic factors are important in determining peak bone mass and structure, as well as the predisposition to bone deterioration and fragility fractures. Nonetheless, genetic factors alone are not sufficient to explain osteoporosis development and fragility fracture occurrence. Indeed, epigenetic factors, representing a link between individual genetic aspects and environmental influences, are also strongly suspected to be involved in bone biology and osteoporosis. Recently, alterations in epigenetic mechanisms and their activity have been associated with aging. Also, bone metabolism has been demonstrated to be under the control of epigenetic mechanisms. Runt-related transcription factor 2 (RUNX2, the master transcription factor of osteoblast differentiation, has been shown to be regulated by histone deacetylases and microRNAs (miRNAs. Some miRNAs were also proven to have key roles in the regulation of Wnt signalling in osteoblastogenesis, and to be important for the positive or negative regulation of both osteoblast and osteoclast differentiation. Exogenous and environmental stimuli, influencing the functionality of epigenetic mechanisms involved in the regulation of bone metabolism, may contribute to the development of osteoporosis and other bone disorders, in synergy with genetic determinants. The progressive understanding of roles of epigenetic mechanisms in normal bone metabolism and in multifactorial bone disorders will be very helpful for a better comprehension of disease pathogenesis and translation of this information into clinical practice. A deep understanding of these mechanisms could help in the future tailoring of proper individual treatments, according to precision medicine’s principles.

Epigenetic Mechanisms in Bone Biology and Osteoporosis: Can They Drive Therapeutic Choices?

Science.gov (United States)

Marini, Francesca; Cianferotti, Luisella; Brandi, Maria Luisa

2016-08-12

Osteoporosis is a complex multifactorial disorder of the skeleton. Genetic factors are important in determining peak bone mass and structure, as well as the predisposition to bone deterioration and fragility fractures. Nonetheless, genetic factors alone are not sufficient to explain osteoporosis development and fragility fracture occurrence. Indeed, epigenetic factors, representing a link between individual genetic aspects and environmental influences, are also strongly suspected to be involved in bone biology and osteoporosis. Recently, alterations in epigenetic mechanisms and their activity have been associated with aging. Also, bone metabolism has been demonstrated to be under the control of epigenetic mechanisms. Runt-related transcription factor 2 (RUNX2), the master transcription factor of osteoblast differentiation, has been shown to be regulated by histone deacetylases and microRNAs (miRNAs). Some miRNAs were also proven to have key roles in the regulation of Wnt signalling in osteoblastogenesis, and to be important for the positive or negative regulation of both osteoblast and osteoclast differentiation. Exogenous and environmental stimuli, influencing the functionality of epigenetic mechanisms involved in the regulation of bone metabolism, may contribute to the development of osteoporosis and other bone disorders, in synergy with genetic determinants. The progressive understanding of roles of epigenetic mechanisms in normal bone metabolism and in multifactorial bone disorders will be very helpful for a better comprehension of disease pathogenesis and translation of this information into clinical practice. A deep understanding of these mechanisms could help in the future tailoring of proper individual treatments, according to precision medicine's principles.

Epigenetics: What it is about?

Directory of Open Access Journals (Sweden)

Saade E.

2014-01-01

Full Text Available Epigenetics has captured the attention of scientists in the past decades, yet its scope has been continuously changing. In this paper, we give an overview on how and why its definition has evolved and suggest several clarification on the concepts used in this field. Waddington coined the term in 1942 to describe genes interaction with each other and with their environment and insisted on dissociating these events from development. Then, Holliday and others argued that epigenetic phenomena are characterized by their heritability. However, differentiated cells can maintain their phenotypes for decades without undergoing division, which points out the limitation of the «heritability» criterion for a particular phenomenon to qualify as epigenetic. «Epigenetic stability» encompasses traits preservation in both dividing and non dividing cells. Likewise, the use of the term «epigenetic regulation» has been misleading as it overlaps with «regulation of gene expression», whereas «epigenetic information» clearly distinguishes epigenetic from genetic phenomena. Consequently, how could epigenetic information be transmitted and perpetuated? The term «epigenetic templating» has been proposed to refer to a general mechanism of perpetuation of epigenetic information that is based on the preferential activity of enzymes that deposit a particular epigenetic mark on macromolecular complexes already containing the same mark. Another issue that we address is the role of epigenetic information. Not only it is important in allowing alternative interpretations of genetic information, but it appears to be important in protecting the genome, as can be illustrated by bacterial endonucleases that targets non methylated DNA – i. e. foreign DNA – and not the endogenous methylated DNA.

Epigenetic Aspects of Posttraumatic Stress Disorder

Directory of Open Access Journals (Sweden)

Ulrike Schmidt

2011-01-01

Full Text Available Development of psychiatric diseases such as posttraumatic stress disorder (PTSD invokes, as with most complex diseases, both genetic and environmental factors. The era of genome-wide high throughput technologies has sparked the initiation of genotype screenings in large cohorts of diseased and control individuals, but had limited success in identification of disease causing genetic variants. It has become evident that these efforts at the genomic level need to be complemented with endeavours in elucidating the proteome, transcriptome and epigenetic profiles. Epigenetics is attractive in particular because there is accumulating evidence that the lasting impact of adverse life events is reflected in certain covalent modifications of the chromatin.

Epigenetic regulation of fetal bone development and placental transfer of nutrients: progress for osteoporosis.

Science.gov (United States)

Bocheva, Georgeta; Boyadjieva, Nadka

2011-12-01

Osteoporosis is a common age-related disorder and causes acute and long-term disability and economic cost. Many factors influence the accumulation of bone minerals, including heredity, diet, physical activity, gender, endocrine functions, and risk factors such as alcohol, drug abuse, some pharmacological drugs or cigarette smoking. The pathology of bone development during intrauterine life is a factor for osteoporosis. Moreover, the placental transfer of nutrients plays an important role in the building of bones of fetuses. The importance of maternal calcium intake and vitamin D status are highlighted in this review. Various environmental factors including nutrition state or maternal stress may affect the epigenetic state of a number of genes during fetal development of bones. Histone modifications as histone hypomethylation, histone hypermethylation, hypoacetylation, etc. are involved in chromatin remodeling, known to contribute to the epigenetic landscape of chromosomes, and play roles in both fetal bone development and osteoporosis. This review will give an overview of epigenetic modulation of bone development and placental transfer of nutrients. In addition, the data from animal and human studies support the role of epigenetic modulation of calcium and vitamin D in the pathogenesis of osteoporosis. We review the evidence suggesting that various genes are involved in regulation of osteoclast formation and differentiation by osteoblasts and stem cells. Epigenetic changes in growth factors as well as cytokines play a rol in fetal bone development. On balance, the data suggest that there is a link between epigenetic changes in placental transfer of nutrients, including calcium and vitamin D, abnormal intrauterine bone development and pathogenesis of osteoporosis.

Correlation of LNCR rasiRNAs Expression with Heterochromatin Formation during Development of the Holocentric Insect Spodoptera frugiperda

Science.gov (United States)

Stanojcic, Slavica; Gimenez, Sylvie; Permal, Emmanuelle; Cousserans, François; Quesneville, Hadi; Fournier, Philippe; d'Alençon, Emmanuelle

2011-01-01

Repeat-associated small interfering RNAs (rasiRNAs) are derived from various genomic repetitive elements and ensure genomic stability by silencing endogenous transposable elements. Here we describe a novel subset of 46 rasiRNAs named LNCR rasiRNAs due to their homology with one long non-coding RNA (LNCR) of Spodoptera frugiperda. LNCR operates as the intermediate of an unclassified transposable element (TE-LNCR). TE-LNCR is a very invasive transposable element, present in high copy numbers in the S. frugiperda genome. LNCR rasiRNAs are single-stranded RNAs without a prominent nucleotide motif, which are organized in two distinct, strand-specific clusters. The expression of LNCR and LNCR rasiRNAs is developmentally regulated. Formation of heterochromatin in the genomic region where three copies of the TE-LNCR are embedded was followed by chromatin immunoprecipitation (ChIP) and we observed this chromatin undergo dynamic changes during development. In summary, increased LNCR expression in certain developmental stages is followed by the appearance of a variety of LNCR rasiRNAs which appears to correlate with subsequent accumulation of a heterochromatic histone mark and silencing of the genomic region with TE-LNCR. These results support the notion that a repeat-associated small interfering RNA pathway is linked to heterochromatin formation and/or maintenance during development to establish repression of the TE-LNCR transposable element. This study provides insights into the rasiRNA silencing pathway and its role in the formation of fluctuating heterochromatin during the development of one holocentric organism. PMID:21980354

Epigenetic changes of Arabidopsis genome associated with altered DNA methyltransferase and demethylase expressions after gamma irradiation

International Nuclear Information System (INIS)

Kim, Ji Eun; Cho, Eun Ju; Kim, Ji Hong; Chung, Byung Yeoup; Kim, Jin Hong

2012-01-01

DNA methylation at carbon 5 of cytosines is a hall mark of epigenetic inactivation and heterochromatin in both plants and mammals. In Arabidopsis, DNA methylation has two roles that protect the genome from selfish DNA elements and regulate gene expression. Plant genome has three types of DNA methyltransferase, METHYLTRANSFERASE 1 (MET1), DOMAINREARRANGED METHYLASE (DRM) and CHROMOMETHYLASE 3 (CMT3) that are capable of methylating CG, CHG (where H is A, T, or C) and CHH sites, respectively. MET1 is a maintenance DNA methyltransferase that controls CG methylation. Two members of the DRM family, DRM1 and DRM2, are responsible for de novo methylation of CG, CHG, and CHH sites but show a preference for CHH sites. Finally, CMT3 principally carries out CHG methylation and is involved in both de novo methylation and maintenance. Alternatively, active DNA demethylation may occur through the glycosylase activity by removing the methylcytosines from DNA. It may have essential roles in preventing transcriptional silencing of transgenes and endogenous genes and in activating the expression of imprinted genes. DNA demetylation in Arabidopsis is mediated by the DEMETER (DME) family of bifunctional DNA glycosylase. Three targets of DME are MEA (MEDEA), FWA (FLOWERING WAGENINGEN), and FIS2 (FERTILIZATION INDEPENDENT SEED 2). The DME family contains DEMETER-LIKE 2 (DML2), DML3, and REPRESSOR OF SILENING 1 (ROS1). DNA demetylation by ROS1, DML2, and DML3 protect the hypermethylation of specific genome loci. ROS1 is necessary to suppress the promoter methylation and the silencing of endogenous genes. In contrast, the function of DML2 and DML3 has not been reported. Several recent studies have suggested that epigenetic alterations such as change in DNA methylation and histone modification should be caused in plant genomes upon exposure to ionizing radiation. However, there is a lack of data exploring the underlying mechanisms. Therefore, the present study aims to characterize and

Epigenetic changes of Arabidopsis genome associated with altered DNA methyltransferase and demethylase expressions after gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Kim, Ji Eun; Cho, Eun Ju; Kim, Ji Hong; Chung, Byung Yeoup; Kim, Jin Hong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-05-15

DNA methylation at carbon 5 of cytosines is a hall mark of epigenetic inactivation and heterochromatin in both plants and mammals. In Arabidopsis, DNA methylation has two roles that protect the genome from selfish DNA elements and regulate gene expression. Plant genome has three types of DNA methyltransferase, METHYLTRANSFERASE 1 (MET1), DOMAINREARRANGED METHYLASE (DRM) and CHROMOMETHYLASE 3 (CMT3) that are capable of methylating CG, CHG (where H is A, T, or C) and CHH sites, respectively. MET1 is a maintenance DNA methyltransferase that controls CG methylation. Two members of the DRM family, DRM1 and DRM2, are responsible for de novo methylation of CG, CHG, and CHH sites but show a preference for CHH sites. Finally, CMT3 principally carries out CHG methylation and is involved in both de novo methylation and maintenance. Alternatively, active DNA demethylation may occur through the glycosylase activity by removing the methylcytosines from DNA. It may have essential roles in preventing transcriptional silencing of transgenes and endogenous genes and in activating the expression of imprinted genes. DNA demetylation in Arabidopsis is mediated by the DEMETER (DME) family of bifunctional DNA glycosylase. Three targets of DME are MEA (MEDEA), FWA (FLOWERING WAGENINGEN), and FIS2 (FERTILIZATION INDEPENDENT SEED 2). The DME family contains DEMETER-LIKE 2 (DML2), DML3, and REPRESSOR OF SILENING 1 (ROS1). DNA demetylation by ROS1, DML2, and DML3 protect the hypermethylation of specific genome loci. ROS1 is necessary to suppress the promoter methylation and the silencing of endogenous genes. In contrast, the function of DML2 and DML3 has not been reported. Several recent studies have suggested that epigenetic alterations such as change in DNA methylation and histone modification should be caused in plant genomes upon exposure to ionizing radiation. However, there is a lack of data exploring the underlying mechanisms. Therefore, the present study aims to characterize and

Epigenetic modifications in prostate cancer.

Science.gov (United States)

Ngollo, Marjolaine; Dagdemir, Aslihan; Karsli-Ceppioglu, Seher; Judes, Gaelle; Pajon, Amaury; Penault-Llorca, Frederique; Boiteux, Jean-Paul; Bignon, Yves-Jean; Guy, Laurent; Bernard-Gallon, Dominique J

2014-01-01

Prostate cancer is the most common cancer in men and the second leading cause of cancer deaths in men in France. Apart from the genetic alterations in prostate cancer, epigenetics modifications are involved in the development and progression of this disease. Epigenetic events are the main cause in gene regulation and the three most epigenetic mechanisms studied include DNA methylation, histone modifications and microRNA expression. In this review, we summarized epigenetic mechanisms in prostate cancer. Epigenetic drugs that inhibit DNA methylation, histone methylation and histone acetylation might be able to reactivate silenced gene expression in prostate cancer. However, further understanding of interactions of these enzymes and their effects on transcription regulation in prostate cancer is needed and has become a priority in biomedical research. In this study, we summed up epigenetic changes with emphasis on pharmacologic epigenetic target agents.

Transgenerational epigenetics of parental exposure to ionising radiation and other mutagens

International Nuclear Information System (INIS)

Dubrova, Yuri E.

2013-01-01

Recent studies have established that epigenetic changes play an important role in many common human diseases, including cancer. Given that the epigenetic landscape of the mammalian cell is not fixed and undergoes massive reprogramming during development, it can potentially be affected by a variety of environmental factors. As the majority of the de novo epigenetic marks, including DNA methylation, are faithfully reproduced during DNA replication, they are transmissible through many cell divisions and, in some cases, can be passed from parents to their offspring. An increasing body of experimental evidence from animal and human studies suggests that environmentally-induced epigenetic changes can be inherited by subsequent generations and can result in transgenerational phenotypic alterations, including predisposition to common diseases

Epigenetic regulation of ageing: linking environmental inputs to genomic stability

Science.gov (United States)

Benayoun, Bérénice A.; Pollina, Elizabeth A.; Brunet, Anne

2016-01-01

Preface Ageing is affected by both genetic and non-genetic factors. Here, we review the chromatin-based epigenetic changes that occur during ageing, the role of chromatin modifiers in modulating lifespan and the importance of epigenetic signatures as biomarkers of ageing. We also discuss how epigenome remodeling by environmental stimuli impacts several aspects of transcription and genomic stability, with important consequences on longevity, and outline epigenetic differences between the ‘mortal soma’ and the ‘immortal germline’. Finally, we discuss the inheritance of ageing characteristics and potential chromatin-based strategies to delay or reverse hallmarks of ageing or age-related diseases. PMID:26373265

Gene × Environment Interactions in Autism Spectrum Disorders: Role of Epigenetic Mechanisms

Science.gov (United States)

Tordjman, Sylvie; Somogyi, Eszter; Coulon, Nathalie; Kermarrec, Solenn; Cohen, David; Bronsard, Guillaume; Bonnot, Olivier; Weismann-Arcache, Catherine; Botbol, Michel; Lauth, Bertrand; Ginchat, Vincent; Roubertoux, Pierre; Barburoth, Marianne; Kovess, Viviane; Geoffray, Marie-Maude; Xavier, Jean

2014-01-01

Several studies support currently the hypothesis that autism etiology is based on a polygenic and epistatic model. However, despite advances in epidemiological, molecular and clinical genetics, the genetic risk factors remain difficult to identify, with the exception of a few chromosomal disorders and several single gene disorders associated with an increased risk for autism. Furthermore, several studies suggest a role of environmental factors in autism spectrum disorders (ASD). First, arguments for a genetic contribution to autism, based on updated family and twin studies, are examined. Second, a review of possible prenatal, perinatal, and postnatal environmental risk factors for ASD are presented. Then, the hypotheses are discussed concerning the underlying mechanisms related to a role of environmental factors in the development of ASD in association with genetic factors. In particular, epigenetics as a candidate biological mechanism for gene × environment interactions is considered and the possible role of epigenetic mechanisms reported in genetic disorders associated with ASD is discussed. Furthermore, the example of in utero exposure to valproate provides a good illustration of epigenetic mechanisms involved in ASD and innovative therapeutic strategies. Epigenetic remodeling by environmental factors opens new perspectives for a better understanding, prevention, and early therapeutic intervention of ASD. PMID:25136320

Genetic, epigenetic and exogenetic information in development and evolution.

Science.gov (United States)

Griffiths, Paul E

2017-10-06

The idea that development is the expression of information accumulated during evolution and that heredity is the transmission of this information is surprisingly hard to cash out in strict, scientific terms. This paper seeks to do so using the sense of information introduced by Francis Crick in his sequence hypothesis and central dogma of molecular biology. It focuses on Crick's idea of precise determination. This is analysed using an information-theoretic measure of causal specificity. This allows us to reconstruct some of Crick's claims about information in transcription and translation. Crick's approach to information has natural extensions to non-coding regions of DNA, to epigenetic marks, and to the genetic or environmental upstream causes of those epigenetic marks. Epigenetic information cannot be reduced to genetic information. The existence of biological information in epigenetic and exogenetic factors is relevant to evolution as well as to development.

Epigenetics and Epigenomics of Plants.

Science.gov (United States)

Yadav, Chandra Bhan; Pandey, Garima; Muthamilarasan, Mehanathan; Prasad, Manoj

2018-01-23

The genetic material DNA in association with histone proteins forms the complex structure called chromatin, which is prone to undergo modification through certain epigenetic mechanisms including cytosine DNA methylation, histone modifications, and small RNA-mediated methylation. Alterations in chromatin structure lead to inaccessibility of genomic DNA to various regulatory proteins such as transcription factors, which eventually modulates gene expression. Advancements in high-throughput sequencing technologies have provided the opportunity to study the epigenetic mechanisms at genome-wide levels. Epigenomic studies using high-throughput technologies will widen the understanding of mechanisms as well as functions of regulatory pathways in plant genomes, which will further help in manipulating these pathways using genetic and biochemical approaches. This technology could be a potential research tool for displaying the systematic associations of genetic and epigenetic variations, especially in terms of cytosine methylation onto the genomic region in a specific cell or tissue. A comprehensive study of plant populations to correlate genotype to epigenotype and to phenotype, and also the study of methyl quantitative trait loci (QTL) or epiGWAS, is possible by using high-throughput sequencing methods, which will further accelerate molecular breeding programs for crop improvement. Graphical Abstract.

The epigenetic bottleneck of neurodegenerative and psychiatric diseases.

Science.gov (United States)

Sananbenesi, Farahnaz; Fischer, Andre

2009-11-01

The orchestrated expression of genes is essential for the development and survival of every organism. In addition to the role of transcription factors, the availability of genes for transcription is controlled by a series of proteins that regulate epigenetic chromatin remodeling. The two most studied epigenetic phenomena are DNA methylation and histone-tail modifications. Although a large body of literature implicates the deregulation of histone acetylation and DNA methylation with the pathogenesis of cancer, recently epigenetic mechanisms have also gained much attention in the neuroscientific community. In fact, a new field of research is rapidly emerging and there is now accumulating evidence that the molecular machinery that regulates histone acetylation and DNA methylation is intimately involved in synaptic plasticity and is essential for learning and memory. Importantly, dysfunction of epigenetic gene expression in the brain might be involved in neurodegenerative and psychiatric diseases. In particular, it was found that inhibition of histone deacetylases attenuates synaptic and neuronal loss in animal models for various neurodegenerative diseases and improves cognitive function. In this article, we will summarize recent data in the novel field of neuroepigenetics and discuss the question why epigenetic strategies are suitable therapeutic approaches for the treatment of brain diseases.

From Genetics to Epigenetics: New Perspectives in Tourette Syndrome Research

Science.gov (United States)

Pagliaroli, Luca; Vető, Borbála; Arányi, Tamás; Barta, Csaba

2016-01-01

Gilles de la Tourette Syndrome (TS) is a neurodevelopmental disorder marked by the appearance of multiple involuntary motor and vocal tics. TS presents high comorbidity rates with other disorders such as attention deficit hyperactivity disorder (ADHD) and obsessive compulsive disorder (OCD). TS is highly heritable and has a complex polygenic background. However, environmental factors also play a role in the manifestation of symptoms. Different epigenetic mechanisms may represent the link between these two causalities. Epigenetic regulation has been shown to have an impact in the development of many neuropsychiatric disorders, however very little is known about its effects on Tourette Syndrome. This review provides a summary of the recent findings in genetic background of TS, followed by an overview on different epigenetic mechanisms, such as DNA methylation, histone modifications, and non-coding RNAs in the regulation of gene expression. Epigenetic studies in other neurological and psychiatric disorders are discussed along with the TS-related epigenetic findings available in the literature to date. Moreover, we are proposing that some general epigenetic mechanisms seen in other neuropsychiatric disorders may also play a role in the pathogenesis of TS. PMID:27462201

Transcription factors, coregulators, and epigenetic marks are linearly correlated and highly redundant.

Directory of Open Access Journals (Sweden)

Tobias Ahsendorf

Full Text Available The DNA microstates that regulate transcription include sequence-specific transcription factors (TFs, coregulatory complexes, nucleosomes, histone modifications, DNA methylation, and parts of the three-dimensional architecture of genomes, which could create an enormous combinatorial complexity across the genome. However, many proteins and epigenetic marks are known to colocalize, suggesting that the information content encoded in these marks can be compressed. It has so far proved difficult to understand this compression in a systematic and quantitative manner. Here, we show that simple linear models can reliably predict the data generated by the ENCODE and Roadmap Epigenomics consortia. Further, we demonstrate that a small number of marks can predict all other marks with high average correlation across the genome, systematically revealing the substantial information compression that is present in different cell lines. We find that the linear models for activating marks are typically cell line-independent, while those for silencing marks are predominantly cell line-specific. Of particular note, a nuclear receptor corepressor, transducin beta-like 1 X-linked receptor 1 (TBLR1, was highly predictive of other marks in two hematopoietic cell lines. The methodology presented here shows how the potentially vast complexity of TFs, coregulators, and epigenetic marks at eukaryotic genes is highly redundant and that the information present can be compressed onto a much smaller subset of marks. These findings could be used to efficiently characterize cell lines and tissues based on a small number of diagnostic marks and suggest how the DNA microstates, which regulate the expression of individual genes, can be specified.

Microbiome, inflammation, epigenetic alterations, and mental diseases.

Science.gov (United States)

Alam, Reza; Abdolmaleky, Hamid M; Zhou, Jin-Rong

2017-09-01

Major mental diseases such as autism, bipolar disorder, schizophrenia, and major depressive disorder are debilitating illnesses with complex etiologies. Recent findings show that the onset and development of these illnesses cannot be well described by the one-gene; one-disease approach. Instead, their clinical presentation is thought to result from the regulative interplay of a large number of genes. Even though the involvement of many genes are likely, up regulating and activation or down regulation and silencing of these genes by the environmental factors play a crucial role in contributing to their pathogenesis. Much of this interplay may be moderated by epigenetic changes. Similar to genetic mutations, epigenetic modifications such as DNA methylation, histone modifications, and RNA interference can influence gene expression and therefore may cause behavioral and neuronal changes observed in mental disorders. Environmental factors such as diet, gut microbiota, and infections have significant role in these epigenetic modifications. Studies show that bioactive nutrients and gut microbiota can alter either DNA methylation and histone signatures through a variety of mechanisms. Indeed, microbes within the human gut may play a significant role in the regulation of various elements of "gut-brain axis," via their influence on inflammatory cytokines and production of antimicrobial peptides that affect the epigenome through their involvement in generating short chain fatty acids, vitamin synthesis, and nutrient absorption. In addition, they may participate in-gut production of many common neurotransmitters. In this review we will consider the potential interactions of diet, gastrointestinal microbiome, inflammation, and epigenetic alterations in psychiatric disorders. © 2017 Wiley Periodicals, Inc.

Epigenetics and allergy: from basic mechanisms to clinical applications.

Science.gov (United States)

Potaczek, Daniel P; Harb, Hani; Michel, Sven; Alhamwe, Bilal Alashkar; Renz, Harald; Tost, Jörg

2017-04-01

Allergic diseases are on the rise in the Western world and well-known allergy-protecting and -driving factors such as microbial and dietary exposure, pollution and smoking mediate their influence through alterations of the epigenetic landscape. Here, we review key facts on the involvement of epigenetic modifications in allergic diseases and summarize and critically evaluate the lessons learned from epigenome-wide association studies. We show the potential of epigenetic changes for various clinical applications: as diagnostic tools, to assess tolerance following immunotherapy or possibly predict the success of therapy at an early time point. Furthermore, new technological advances such as epigenome editing and DNAzymes will allow targeted alterations of the epigenome in the future and provide novel therapeutic tools.

Role of epigenetics in developmental biology and transgenerational inheritance.

Science.gov (United States)

Skinner, Michael K

2011-03-01

The molecular mechanisms involved in developmental biology and cellular differentiation have traditionally been considered to be primarily genetic. Environmental factors that influence early life critical windows of development generally do not have the capacity to modify genome sequence, nor promote permanent genetic modifications. Epigenetics provides a molecular mechanism for environment to influence development, program cellular differentiation, and alter the genetic regulation of development. The current review discusses how epigenetics can cooperate with genetics to regulate development and allow for greater plasticity in response to environmental influences. This impacts area such as cellular differentiation, tissue development, environmental induced disease etiology, epigenetic transgenerational inheritance, and the general systems biology of organisms and evolution. Copyright © 2011 Wiley-Liss, Inc.

Epigenetic Editing: targeted rewriting of epigenetic marks to modulate expression of selected target genes.

NARCIS (Netherlands)

de Groote, M.L.; Verschure, P.J.; Rots, M.G.

2012-01-01

Despite significant advances made in epigenetic research in recent decades, many questions remain unresolved, especially concerning cause and consequence of epigenetic marks with respect to gene expression modulation (GEM). Technologies allowing the targeting of epigenetic enzymes to predetermined

Epigenetic Editing : targeted rewriting of epigenetic marks to modulate expression of selected target genes

NARCIS (Netherlands)

de Groote, Marloes L.; Verschure, Pernette J.; Rots, Marianne G.

2012-01-01

Despite significant advances made in epigenetic research in recent decades, many questions remain unresolved, especially concerning cause and consequence of epigenetic marks with respect to gene expression modulation (GEM). Technologies allowing the targeting of epigenetic enzymes to predetermined

Scrutinizing the epigenetics revolution

Science.gov (United States)

Meloni, Maurizio; Testa, Giuseppe

2014-01-01

Epigenetics is one of the most rapidly expanding fields in the life sciences. Its rise is frequently framed as a revolutionary turn that heralds a new epoch both for gene-based epistemology and for the wider discourse on life that pervades knowledge-intensive societies of the molecular age. The fundamentals of this revolution remain however to be scrutinized, and indeed the very contours of what counts as ‘epigenetic' are often blurred. This is reflected also in the mounting discourse on the societal implications of epigenetics, in which vast expectations coexist with significant uncertainty about what aspects of this science are most relevant for politics or policy alike. This is therefore a suitable time to reflect on the directions that social theory could most productively take in the scrutiny of this revolution. Here we take this opportunity in both its scholarly and normative dimension, that is, proposing a roadmap for social theorizing on epigenetics that does not shy away from, and indeed hopefully guides, the framing of its most socially relevant outputs. To this end, we start with an epistemological reappraisal of epigenetic discourse that valorizes the blurring of meanings as a critical asset for the field and privileged analytical entry point. We then propose three paths of investigation. The first looks at the structuring elements of controversies and visions around epigenetics. The second probes the mutual constitution between the epigenetic reordering of living phenomena and the normative settlements that orient individual and collective responsibilities. The third highlights the material import of epigenetics and the molecularization of culture that it mediates. We suggest that these complementary strands provide both an epistemically and socially self-reflective framework to advance the study of epigenetics as a molecular juncture between nature and nurture and thus as the new critical frontier in the social studies of the life sciences. PMID

The Arabidopsis GAGA-Binding Factor BASIC PENTACYSTEINE6 Recruits the POLYCOMB-REPRESSIVE COMPLEX1 Component LIKE HETEROCHROMATIN PROTEIN1 to GAGA DNA Motifs.

Science.gov (United States)

Hecker, Andreas; Brand, Luise H; Peter, Sébastien; Simoncello, Nathalie; Kilian, Joachim; Harter, Klaus; Gaudin, Valérie; Wanke, Dierk

2015-07-01

Polycomb-repressive complexes (PRCs) play key roles in development by repressing a large number of genes involved in various functions. Much, however, remains to be discovered about PRC-silencing mechanisms as well as their targeting to specific genomic regions. Besides other mechanisms, GAGA-binding factors in animals can guide PRC members in a sequence-specific manner to Polycomb-responsive DNA elements. Here, we show that the Arabidopsis (Arabidopsis thaliana) GAGA-motif binding factor protein basic pentacysteine6 (BPC6) interacts with like heterochromatin protein1 (LHP1), a PRC1 component, and associates with vernalization2 (VRN2), a PRC2 component, in vivo. By using a modified DNA-protein interaction enzyme-linked immunosorbant assay, we could show that BPC6 was required and sufficient to recruit LHP1 to GAGA motif-containing DNA probes in vitro. We also found that LHP1 interacts with VRN2 and, therefore, can function as a possible scaffold between BPC6 and VRN2. The lhp1-4 bpc4 bpc6 triple mutant displayed a pleiotropic phenotype, extreme dwarfism and early flowering, which disclosed synergistic functions of LHP1 and group II plant BPC members. Transcriptome analyses supported this synergy and suggested a possible function in the concerted repression of homeotic genes, probably through histone H3 lysine-27 trimethylation. Hence, our findings suggest striking similarities between animal and plant GAGA-binding factors in the recruitment of PRC1 and PRC2 components to Polycomb-responsive DNA element-like GAGA motifs, which must have evolved through convergent evolution. © 2015 American Society of Plant Biologists. All Rights Reserved.

Neurodevelopmental Disorders and Environmental Toxicants: Epigenetics as an Underlying Mechanism

Science.gov (United States)

2017-01-01

The increasing prevalence of neurodevelopmental disorders, especially autism spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD), calls for more research into the identification of etiologic and risk factors. The Developmental Origin of Health and Disease (DOHaD) hypothesizes that the environment during fetal and childhood development affects the risk for many chronic diseases in later stages of life, including neurodevelopmental disorders. Epigenetics, a term describing mechanisms that cause changes in the chromosome state without affecting DNA sequences, is suggested to be the underlying mechanism, according to the DOHaD hypothesis. Moreover, many neurodevelopmental disorders are also related to epigenetic abnormalities. Experimental and epidemiological studies suggest that exposure to prenatal environmental toxicants is associated with neurodevelopmental disorders. In addition, there is also evidence that environmental toxicants can result in epigenetic alterations, notably DNA methylation. In this review, we first focus on the relationship between neurodevelopmental disorders and environmental toxicants, in particular maternal smoking, plastic-derived chemicals (bisphenol A and phthalates), persistent organic pollutants, and heavy metals. We then review studies showing the epigenetic effects of those environmental factors in humans that may affect normal neurodevelopment. PMID:28567415

Neurodevelopmental Disorders and Environmental Toxicants: Epigenetics as an Underlying Mechanism

Directory of Open Access Journals (Sweden)

Nguyen Quoc Vuong Tran

2017-01-01

Full Text Available The increasing prevalence of neurodevelopmental disorders, especially autism spectrum disorders (ASD and attention deficit hyperactivity disorder (ADHD, calls for more research into the identification of etiologic and risk factors. The Developmental Origin of Health and Disease (DOHaD hypothesizes that the environment during fetal and childhood development affects the risk for many chronic diseases in later stages of life, including neurodevelopmental disorders. Epigenetics, a term describing mechanisms that cause changes in the chromosome state without affecting DNA sequences, is suggested to be the underlying mechanism, according to the DOHaD hypothesis. Moreover, many neurodevelopmental disorders are also related to epigenetic abnormalities. Experimental and epidemiological studies suggest that exposure to prenatal environmental toxicants is associated with neurodevelopmental disorders. In addition, there is also evidence that environmental toxicants can result in epigenetic alterations, notably DNA methylation. In this review, we first focus on the relationship between neurodevelopmental disorders and environmental toxicants, in particular maternal smoking, plastic-derived chemicals (bisphenol A and phthalates, persistent organic pollutants, and heavy metals. We then review studies showing the epigenetic effects of those environmental factors in humans that may affect normal neurodevelopment.

Epigenetics of cell fate reprogramming and its implications for neurological disorders modelling.

Science.gov (United States)

Grzybek, Maciej; Golonko, Aleksandra; Walczak, Marta; Lisowski, Pawel

2017-03-01

The reprogramming of human induced pluripotent stem cells (hiPSCs) proceeds in a stepwise manner with reprogramming factors binding and epigenetic composition changes during transition to maintain the epigenetic landscape, important for pluripotency. There arises a question as to whether the aberrant epigenetic state after reprogramming leads to epigenetic defects in induced stem cells causing unpredictable long term effects in differentiated cells. In this review, we present a comprehensive view of epigenetic alterations accompanying reprogramming, cell maintenance and differentiation as factors that influence applications of hiPSCs in stem cell based technologies. We conclude that sample heterogeneity masks DNA methylation signatures in subpopulations of cells and thus believe that beside a genetic evaluation, extensive epigenomic screening should become a standard procedure to ensure hiPSCs state before they are used for genome editing and differentiation into neurons of interest. In particular, we suggest that exploitation of the single-cell composition of the epigenome will provide important insights into heterogeneity within hiPSCs subpopulations to fast forward development of reliable hiPSC-based analytical platforms in neurological disorders modelling and before completed hiPSC technology will be implemented in clinical approaches. Copyright © 2016 Elsevier Inc. All rights reserved.

Induced pluripotent stem cells reprogramming: Epigenetics and applications in the regenerative medicine

Directory of Open Access Journals (Sweden)

Kátia Maria Sampaio Gomes

Full Text Available Summary Induced pluripotent stem cells (iPSCs are somatic cells reprogrammed into an embryonic-like pluripotent state by the expression of specific transcription factors. iPSC technology is expected to revolutionize regenerative medicine in the near future. Despite the fact that these cells have the capacity to self-renew, they present low efficiency of reprogramming. Recent studies have demonstrated that the previous somatic epigenetic signature is a limiting factor in iPSC performance. Indeed, the process of effective reprogramming involves a complete remodeling of the existing somatic epigenetic memory, followed by the establishment of a "new epigenetic signature" that complies with the new type of cell to be differentiated. Therefore, further investigations of epigenetic modifications associated with iPSC reprogramming are required in an attempt to improve their self-renew capacity and potency, as well as their application in regenerative medicine, with a new strategy to reduce the damage in degenerative diseases. Our review aimed to summarize the most recent findings on epigenetics and iPSC, focusing on DNA methylation, histone modifications and microRNAs, highlighting their potential in translating cell therapy into clinics.

Epigenetics: a new frontier in dentistry.

Science.gov (United States)

Williams, S D; Hughes, T E; Adler, C J; Brook, A H; Townsend, G C

2014-06-01

In 2007, only four years after the completion of the Human Genome Project, the journal Science announced that epigenetics was the 'breakthrough of the year'. Time magazine placed it second in the top 10 discoveries of 2009. While our genetic code (i.e. our DNA) contains all of the information to produce the elements we require to function, our epigenetic code determines when and where genes in the genetic code are expressed. Without the epigenetic code, the genetic code is like an orchestra without a conductor. Although there is now a substantial amount of published research on epigenetics in medicine and biology, epigenetics in dental research is in its infancy. However, epigenetics promises to become increasingly relevant to dentistry because of the role it plays in gene expression during development and subsequently potentially influencing oral disease susceptibility. This paper provides a review of the field of epigenetics aimed specifically at oral health professionals. It defines epigenetics, addresses the underlying concepts and provides details about specific epigenetic molecular mechanisms. Further, we discuss some of the key areas where epigenetics is implicated, and review the literature on epigenetics research in dentistry, including its relevance to clinical disciplines. This review considers some implications of epigenetics for the future of dental practice, including a 'personalized medicine' approach to the management of common oral diseases. © 2014 Australian Dental Association.

Epigenetics of Estrogen Receptor Signaling: Role in Hormonal Cancer Progression and Therapy

International Nuclear Information System (INIS)

Mann, Monica; Cortez, Valerie; Vadlamudi, Ratna K.

2011-01-01

Estrogen receptor (ERα) signaling plays a key role in hormonal cancer progression. ERα is a ligand-dependent transcription factor that modulates gene transcription via recruitment to the target gene chromatin. Emerging evidence suggests that ERα signaling has the potential to contribute to epigenetic changes. Estrogen stimulation is shown to induce several histone modifications at the ERα target gene promoters including acetylation, phosphorylation and methylation via dynamic interactions with histone modifying enzymes. Deregulation of enzymes involved in the ERα -mediated epigenetic pathway could play a vital role in ERα driven neoplastic processes. Unlike genetic alterations, epigenetic changes are reversible, and hence offer novel therapeutic opportunities to reverse ERα driven epigenetic changes. In this review, we summarize current knowledge on mechanisms by which ERα signaling potentiates epigenetic changes in cancer cells via histone modifications

Epigenetics of Estrogen Receptor Signaling: Role in Hormonal Cancer Progression and Therapy

Energy Technology Data Exchange (ETDEWEB)

Mann, Monica; Cortez, Valerie [Department of Cellular and Structural Biology, UTHSCSA, 7703 Floyd Curl Drive, San Antonio, TX 78229 (United States); Vadlamudi, Ratna K., E-mail: vadlamudi@uthscsa.edu [Department of Obstetrics and Gynecology, UTHSCSA, 7703 Floyd Curl Drive, San Antonio, TX 78229 (United States)

2011-03-29

Estrogen receptor (ERα) signaling plays a key role in hormonal cancer progression. ERα is a ligand-dependent transcription factor that modulates gene transcription via recruitment to the target gene chromatin. Emerging evidence suggests that ERα signaling has the potential to contribute to epigenetic changes. Estrogen stimulation is shown to induce several histone modifications at the ERα target gene promoters including acetylation, phosphorylation and methylation via dynamic interactions with histone modifying enzymes. Deregulation of enzymes involved in the ERα -mediated epigenetic pathway could play a vital role in ERα driven neoplastic processes. Unlike genetic alterations, epigenetic changes are reversible, and hence offer novel therapeutic opportunities to reverse ERα driven epigenetic changes. In this review, we summarize current knowledge on mechanisms by which ERα signaling potentiates epigenetic changes in cancer cells via histone modifications.

Loss of maternal ATRX results in centromere instability and aneuploidy in the mammalian oocyte and pre-implantation embryo.

Directory of Open Access Journals (Sweden)

Claudia Baumann

2010-09-01

Full Text Available The α-thalassemia/mental retardation X-linked protein (ATRX is a chromatin-remodeling factor known to regulate DNA methylation at repetitive sequences of the human genome. We have previously demonstrated that ATRX binds to pericentric heterochromatin domains in mouse oocytes at the metaphase II stage where it is involved in mediating chromosome alignment at the meiotic spindle. However, the role of ATRX in the functional differentiation of chromatin structure during meiosis is not known. To test ATRX function in the germ line, we developed an oocyte-specific transgenic RNAi knockdown mouse model. Our results demonstrate that ATRX is required for heterochromatin formation and maintenance of chromosome stability during meiosis. During prophase I arrest, ATRX is necessary to recruit the transcriptional regulator DAXX (death domain associated protein to pericentric heterochromatin. At the metaphase II stage, transgenic ATRX-RNAi oocytes exhibit abnormal chromosome morphology associated with reduced phosphorylation of histone 3 at serine 10 as well as chromosome segregation defects leading to aneuploidy and severely reduced fertility. Notably, a large proportion of ATRX-depleted oocytes and 1-cell stage embryos exhibit chromosome fragments and centromeric DNA-containing micronuclei. Our results provide novel evidence indicating that ATRX is required for centromere stability and the epigenetic control of heterochromatin function during meiosis and the transition to the first mitosis.

Is Glioblastoma an Epigenetic Malignancy?

International Nuclear Information System (INIS)

Maleszewska, Marta; Kaminska, Bozena

2013-01-01

Epigenetic modifications control gene expression by regulating the access of nuclear proteins to their target DNA and have been implicated in both normal cell differentiation and oncogenic transformation. Epigenetic abnormalities can occur both as a cause and as a consequence of cancer. Oncogenic transformation can deeply alter the epigenetic information enclosed in the pattern of DNA methylation or histone modifications. In addition, in some cancers epigenetic dysfunctions can drive oncogenic transformation. Growing evidence emphasizes the interplay between metabolic disturbances, epigenomic changes and cancer, i.e., mutations in the metabolic enzymes SDH, FH, and IDH may contribute to cancer development. Epigenetic-based mechanisms are reversible and the possibility of “resetting” the abnormal cancer epigenome by applying pharmacological or genetic strategies is an attractive, novel approach. Gliomas are incurable with all current therapeutic approaches and new strategies are urgently needed. Increasing evidence suggests the role of epigenetic events in development and/or progression of gliomas. In this review, we summarize current data on the occurrence and significance of mutations in the epigenetic and metabolic enzymes in pathobiology of gliomas. We discuss emerging therapies targeting specific epigenetic modifications or chromatin modifying enzymes either alone or in combination with other treatment regimens

Epigenetic Effects of Diet on Fruit Fly Lifespan: An Investigation to Teach Epigenetics to Biology Students

Science.gov (United States)

Billingsley, James; Carlson, Kimberly A.

2010-01-01

Do our genes exclusively control us, or are other factors at play? Epigenetics can provide a means for students to use inquiry-based methods to understand a complex biological concept. Students research and design an experiment testing whether dietary supplements affect the lifespan of Drosophila melanogaster over multiple generations.

Nuclear dynamics of radiation-induced foci in euchromatin and heterochromatin

International Nuclear Information System (INIS)

Chiolo, Irene; Tang, Jonathan; Georgescu, Walter; Costes, Sylvain V.

2013-01-01

Repair of double strand breaks (DSBs) is essential for cell survival and genome integrity. While much is known about the molecular mechanisms involved in DSB repair and checkpoint activation, the roles of nuclear dynamics of radiation-induced foci (RIF) in DNA repair are just beginning to emerge. Here, we summarize results from recent studies that point to distinct features of these dynamics in two different chromatin environments: heterochromatin and euchromatin. We also discuss how nuclear architecture and chromatin components might control these dynamics, and the need of novel quantification methods for a better description and interpretation of these phenomena. These studies are expected to provide new biomarkers for radiation risk and new strategies for cancer detection and treatment

Nuclear dynamics of radiation-induced foci in euchromatin and heterochromatin

Energy Technology Data Exchange (ETDEWEB)

Chiolo, Irene; Tang, Jonathan; Georgescu, Walter; Costes, Sylvain V.

2013-10-01

Repair of double strand breaks (DSBs) is essential for cell survival and genome integrity. While much is known about the molecular mechanisms involved in DSB repair and checkpoint activation, the roles of nuclear dynamics of radiation-induced foci (RIF) in DNA repair are just beginning to emerge. Here, we summarize results from recent studies that point to distinct features of these dynamics in two different chromatin environments: heterochromatin and euchromatin. We also discuss how nuclear architecture and chromatin components might control these dynamics, and the need of novel quantification methods for a better description and interpretation of these phenomena. These studies are expected to provide new biomarkers for radiation risk and new strategies for cancer detection and treatment.

Clinical relevance of epigenetics in the onset and management of type 2 diabetes mellitus

Science.gov (United States)

Sommese, Linda; Zullo, Alberto; Mancini, Francesco Paolo; Fabbricini, Rossella; Soricelli, Andrea; Napoli, Claudio

2017-01-01

ABSTRACT Epigenetics is involved in the altered expression of gene networks that underlie insulin resistance and insufficiency. Major genes controlling β-cell differentiation and function, such as PAX4, PDX1, and GLP1 receptor, are epigenetically controlled. Epigenetics can cause insulin resistance through immunomediated pro-inflammatory actions related to several factors, such as NF-kB, osteopontin, and Toll-like receptors. Hereafter, we provide a critical and comprehensive summary on this topic with a particular emphasis on translational and clinical aspects. We discuss the effect of epigenetics on β-cell regeneration for cell replacement therapy, the emerging bioinformatics approaches for analyzing the epigenetic contribution to type 2 diabetes mellitus (T2DM), the epigenetic core of the transgenerational inheritance hypothesis in T2DM, and the epigenetic clinical trials on T2DM. Therefore, prevention or reversion of the epigenetic changes occurring during T2DM development may reduce the individual and societal burden of the disease. PMID:28059593

Genetics and epigenetics of rheumatoid arthritis

Science.gov (United States)

Viatte, Sebastien; Plant, Darren; Raychaudhuri, Soumya

2013-01-01

Investigators have made key advances in rheumatoid arthritis (RA) genetics in the past 10 years. Although genetic studies have had limited influence on clinical practice and drug discovery, they are currently generating testable hypotheses to explain disease pathogenesis. Firstly, we review here the major advances in identifying RA genetic susceptibility markers both within and outside of the MHC. Understanding how genetic variants translate into pathogenic mechanisms and ultimately into phenotypes remains a mystery for most of the polymorphisms that confer susceptibility to RA, but functional data are emerging. Interplay between environmental and genetic factors is poorly understood and in need of further investigation. Secondly, we review current knowledge of the role of epigenetics in RA susceptibility. Differences in the epigenome could represent one of the ways in which environmental exposures translate into phenotypic outcomes. The best understood epigenetic phenomena include post-translational histone modifications and DNA methylation events, both of which have critical roles in gene regulation. Epigenetic studies in RA represent a new area of research with the potential to answer unsolved questions. PMID:23381558

[Genetics and epigenetics in autism].

Science.gov (United States)

Nakayama, Atsuo; Masaki, Shiego; Aoki, Eiko

2006-11-01

Autism is a behaviorally defined syndrome characterized by impaired social interaction and communication, and restricted, stereotyped interests and behaviors. Several lines of evidence support the contention that genetic factors are a large component to autism etiology. However, in spite of vigorous genetic studies, no single causative or susceptibility gene common in autism has been identified. Thus multiple susceptibility genes in interaction are considered to account for the disorder. Furthermore, environmental risk factors can accelerate the autism development of. Recent advances in understanding the epigenetic regulation may shed light on the interaction among multiple genetic factors and environmental factors.

Epigenetics of peripheral B cell differentiation and the antibody response

Directory of Open Access Journals (Sweden)

Hong eZan

2015-12-01

Full Text Available Epigenetic modifications, such as histone post-translational modifications, DNA methylation, and alteration of gene expression by non-coding RNAs, including microRNAs (miRNAs and long non-coding RNAs (lncRNAs, are heritable changes that are independent from the genomic DNA sequence. These regulate gene activities and, therefore, cellular functions. Epigenetic modifications act in concert with transcription factors and play critical roles in B cell development and differentiation, thereby modulating antibody responses to foreign- and self-antigens. Upon antigen encounter by mature B cells in the periphery, alterations of these lymphocytes epigenetic landscape are induced by the same stimuli that drive the antibody response. Such alterations instruct B cells to undergo immunoglobulin class switch DNA recombination (CSR and somatic hypermutation (SHM, as well as differentiation to memory B cells or long-lived plasma cells for the immune memory. Inducible histone modifications, together with DNA methylation and miRNAs modulate the transcriptome, particularly the expression of activation-induced cytidine deaminase (AID, which is essential for CSR and SHM, and factors central to plasma cell differentiation, such as B lymphocyte-induced maturation protein-1 (Blimp-1. These inducible B cell-intrinsic epigenetic marks guide the maturation of antibody responses. Combinatorial histone modifications also function as histone codes to target CSR and, possibly, SHM machinery to the Ig loci by recruiting specific adaptors that can stabilize CSR/SHM factors. In addition, lncRNAs, such as recently reported lncRNA-CSR and an lncRNA generated through transcription of the S region that form G-quadruplex structures, are also important for CSR targeting. Epigenetic dysregulation in B cells, including the aberrant expression of non-coding RNAs and alterations of histone modifications and DNA methylation, can result in aberrant antibody responses to foreign antigens

A computational model for histone mark propagation reproduces the distribution of heterochromatin in different human cell types.

Science.gov (United States)

Schwämmle, Veit; Jensen, Ole Nørregaard

2013-01-01

Chromatin is a highly compact and dynamic nuclear structure that consists of DNA and associated proteins. The main organizational unit is the nucleosome, which consists of a histone octamer with DNA wrapped around it. Histone proteins are implicated in the regulation of eukaryote genes and they carry numerous reversible post-translational modifications that control DNA-protein interactions and the recruitment of chromatin binding proteins. Heterochromatin, the transcriptionally inactive part of the genome, is densely packed and contains histone H3 that is methylated at Lys 9 (H3K9me). The propagation of H3K9me in nucleosomes along the DNA in chromatin is antagonizing by methylation of H3 Lysine 4 (H3K4me) and acetylations of several lysines, which is related to euchromatin and active genes. We show that the related histone modifications form antagonized domains on a coarse scale. These histone marks are assumed to be initiated within distinct nucleation sites in the DNA and to propagate bi-directionally. We propose a simple computer model that simulates the distribution of heterochromatin in human chromosomes. The simulations are in agreement with previously reported experimental observations from two different human cell lines. We reproduced different types of barriers between heterochromatin and euchromatin providing a unified model for their function. The effect of changes in the nucleation site distribution and of propagation rates were studied. The former occurs mainly with the aim of (de-)activation of single genes or gene groups and the latter has the power of controlling the transcriptional programs of entire chromosomes. Generally, the regulatory program of gene transcription is controlled by the distribution of nucleation sites along the DNA string.

Obesity and Bariatric Surgery Drive Epigenetic Variation of Spermatozoa in Humans

DEFF Research Database (Denmark)

Donkin, Ida; Versteyhe, Soetkin; Ingerslev, Lars R.

2016-01-01

Obesity is a heritable disorder, with children of obese fathers at higher risk of developing obesity. Environmental factors epigenetically influence somatic tissues, but the contribution of these factors to the establishment of epigenetic patterns in human gametes is unknown. Here, we hypothesized...... of morbidly obese men, surgery-induced weight loss was associated with a dramatic remodeling of sperm DNA methylation, notably at genetic locations implicated in the central control of appetite. Our data provide evidence that the epigenome of human spermatozoa dynamically changes under environmental pressure...

Epigenetics in women's health care.

Science.gov (United States)

Pozharny, Yevgeniya; Lambertini, Luca; Clunie, Garfield; Ferrara, Lauren; Lee, Men-Jean

2010-01-01

Epigenetics refers to structural modifications to genes that do not change the nucleotide sequence itself but instead control and regulate gene expression. DNA methylation, histone modification, and RNA regulation are some of the mechanisms involved in epigenetic modification. Epigenetic changes are believed to be a result of changes in an organism's environment that result in fixed and permanent changes in most differentiated cells. Some environmental changes that have been linked to epigenetic changes include starvation, folic acid, and various chemical exposures. There are periods in an organism's life cycle in which the organism is particularly susceptible to epigenetic influences; these include fertilization, gametogenesis, and early embryo development. These are also windows of opportunity for interventions during the reproductive life cycle of women to improve maternal-child health. New data suggest that epigenetic influences might be involved in the regulation of fetal development and the pathophysiology of adult diseases such as cancer, diabetes, obesity, and neurodevelopmental disorders. Various epigenetic mechanisms may also be involved in the pathogenesis of preeclampsia and intrauterine growth restriction. Additionally, environmental exposures are being held responsible for causing epigenetic changes that lead to a disease process. Exposure to heavy metals, bioflavonoids, and endocrine disruptors, such as bisphenol A and phthalates, has been shown to affect the epigenetic memory of an organism. Their long-term effects are unclear at this point, but many ongoing studies are attempting to elucidate the pathophysiological effects of such gene-environment interactions. (c) 2010 Mount Sinai School of Medicine.

Epigenetic Regulation of Adipokines

Directory of Open Access Journals (Sweden)

Tho X. Pham

2017-08-01

Full Text Available Adipose tissue expansion in obesity leads to changes in the expression of adipokines, adipocyte-specific hormones that can regulate whole body energy metabolism. Epigenetic regulation of gene expression is a mechanism by which cells can alter gene expression through the modifications of DNA and histones. Epigenetic mechanisms, such as DNA methylation and histone modifications, are intimately tied to energy metabolism due to their dependence on metabolic intermediates such as S-adenosylmethionine and acetyl-CoA. Altered expression of adipokines in obesity may be due to epigenetic changes. The goal of this review is to highlight current knowledge of epigenetic regulation of adipokines.

Epigenetics in the Eye: An Overview of the Most Relevant Ocular Diseases

Directory of Open Access Journals (Sweden)

Hanan A. Alkozi

2017-10-01

Full Text Available Sight for mammals is one of the most appreciated senses. In humans there are several factors that contribute to the increment in all kind of eye diseases. This mini-review will focus on some diseases whose prevalence is steadily increasing year after year for non-genetic reasons, namely cataracts, dry eye, and glaucoma. Aging, diet, inflammation, drugs, oxidative stress, seasonal and circadian style-of-live changes are impacting on disease prevalence by epigenetics factors, defined as stable heritable traits that are not explained by changes in DNA sequence. The mini-review will concisely show the data showing epigenetics marks in these diseases and on how knowledge on the epigenetic alterations may guide therapeutic approaches to have a healthy eye.

Epigenetic landscapes reveal transcription factors regulating CD8+ T cell differentiation

Science.gov (United States)

Yu, Bingfei; Zhang, Kai; Milner, J. Justin; Toma, Clara; Chen, Runqiang; Scott-Browne, James P.; Pereira, Renata M.; Crotty, Shane; Chang, John T.; Pipkin, Matthew E.; Wang, Wei; Goldrath, Ananda W.

2017-01-01

Dynamic changes in the expression of transcription factors (TFs) can influence specification of distinct CD8+ T cell fates, but the observation of equivalent expression of TF among differentially-fated precursor cells suggests additional underlying mechanisms. Here, we profiled genome-wide histone modifications, open chromatin and gene expression of naive, terminal-effector, memory-precursor and memory CD8+ T cell populations induced during the in vivo response to bacterial infection. Integration of these data suggested that TF expression and binding contributed to establishment of subset-specific enhancers during differentiation. We developed a new bioinformatics method using the PageRank algorithm to reveal novel TFs influencing the generation of effector and memory populations. The TFs YY1 and Nr3c1, both constitutively expressed during CD8+ T cell differentiation, regulated the formation of terminal-effector and memory-precursor cell-fates, respectively. Our data define the epigenetic landscape of differentiation intermediates, facilitating identification of TFs with previously unappreciated roles in CD8+ T cell differentiation. PMID:28288100

Stress, Epigenetics, and Alcoholism

Science.gov (United States)

Moonat, Sachin; Pandey, Subhash C.

2012-01-01

Acute and chronic stressors have been associated with alterations in mood and increased anxiety that may eventually result in the development of stress-related psychiatric disorders. Stress and associated disorders, including anxiety, are key factors in the development of alcoholism because alcohol consumption can temporarily reduce the drinker’s dysphoria. One molecule that may help mediate the relationship between stress and alcohol consumption is brain-derived neurotrophic factor (BDNF), a protein that regulates the structure and function of the sites where two nerve cells interact and exchange nerve signals (i.e., synapses) and which is involved in numerous physiological processes. Aberrant regulation of BDNF signaling and alterations in synapse activity (i.e., synaptic plasticity) have been associated with the pathophysiology of stress-related disorders and alcoholism. Mechanisms that contribute to the regulation of genetic information without modification of the DNA sequence (i.e., epigenetic mechanisms) may play a role in the complex control of BDNF signaling and synaptic plasticity—for example, by modifying the structure of the DNA–protein complexes (i.e., chromatin) that make up the chromosomes and thereby modulating the expression of certain genes. Studies regarding the epigenetic control of BDNF signaling and synaptic plasticity provide a promising direction to understand the mechanisms mediating the interaction between stress and alcoholism. PMID:23584115

Epigenetics in Cancer: A Hematological Perspective.

Directory of Open Access Journals (Sweden)

Maximilian Stahl

2016-10-01

Full Text Available For several decades, we have known that epigenetic regulation is disrupted in cancer. Recently, an increasing body of data suggests epigenetics might be an intersection of current cancer research trends: next generation sequencing, immunology, metabolomics, and cell aging. The new emphasis on epigenetics is also related to the increasing production of drugs capable of interfering with epigenetic mechanisms and able to trigger clinical responses in even advanced phase patients. In this review, we will use myeloid malignancies as proof of concept examples of how epigenetic mechanisms can trigger or promote oncogenesis. We will also show how epigenetic mechanisms are related to genetic aberrations, and how they affect other systems, like immune response. Finally, we will show how we can try to influence the fate of cancer cells with epigenetic therapy.

Epigenetics in plant tissue culture

NARCIS (Netherlands)

Smulders, M.J.M.; Klerk, de G.J.M.

2011-01-01

Plants produced vegetatively in tissue culture may differ from the plants from which they have been derived. Two major classes of off-types occur: genetic ones and epigenetic ones. This review is about epigenetic aberrations. We discuss recent studies that have uncovered epigenetic modifications at

Recent developments on the role of epigenetics in obesity and metabolic disease.

Science.gov (United States)

van Dijk, Susan J; Tellam, Ross L; Morrison, Janna L; Muhlhausler, Beverly S; Molloy, Peter L

2015-01-01

The increased prevalence of obesity and related comorbidities is a major public health problem. While genetic factors undoubtedly play a role in determining individual susceptibility to weight gain and obesity, the identified genetic variants only explain part of the variation. This has led to growing interest in understanding the potential role of epigenetics as a mediator of gene-environment interactions underlying the development of obesity and its associated comorbidities. Initial evidence in support of a role of epigenetics in obesity and type 2 diabetes mellitus (T2DM) was mainly provided by animal studies, which reported epigenetic changes in key metabolically important tissues following high-fat feeding and epigenetic differences between lean and obese animals and by human studies which showed epigenetic changes in obesity and T2DM candidate genes in obese/diabetic individuals. More recently, advances in epigenetic methodologies and the reduced cost of epigenome-wide association studies (EWAS) have led to a rapid expansion of studies in human populations. These studies have also reported epigenetic differences between obese/T2DM adults and healthy controls and epigenetic changes in association with nutritional, weight loss, and exercise interventions. There is also increasing evidence from both human and animal studies that the relationship between perinatal nutritional exposures and later risk of obesity and T2DM may be mediated by epigenetic changes in the offspring. The aim of this review is to summarize the most recent developments in this rapidly moving field, with a particular focus on human EWAS and studies investigating the impact of nutritional and lifestyle factors (both pre- and postnatal) on the epigenome and their relationship to metabolic health outcomes. The difficulties in distinguishing consequence from causality in these studies and the critical role of animal models for testing causal relationships and providing insight into underlying

Comparative epigenetics: relevance to the regulation of production and health traits in cattle.

Science.gov (United States)

Doherty, Rachael; O' Farrelly, Cliona; Meade, Kieran G

2014-08-01

With the development of genomic, transcriptomic and bioinformatic tools, recent advances in molecular technologies have significantly impacted bovine bioscience research and are revolutionising animal selection and breeding. Integration of epigenetic information represents yet another challenging molecular frontier. Epigenetics is the study of biochemical modifications to DNA and to histones, the proteins that provide stability to DNA. These epigenetic changes are induced by environmental stimuli; they alter gene expression and are potentially heritable. Epigenetics research holds the key to understanding how environmental factors contribute to phenotypic variation in traits of economic importance in cattle including development, nutrition, behaviour and health. In this review, we discuss the potential applications of epigenetics in bovine research, using breakthroughs in human and murine research to signpost the way. © 2014 Stichting International Foundation for Animal Genetics.

Epigenetic Alterations in Fanconi Anaemia: Role in Pathophysiology and Therapeutic Potential.

Directory of Open Access Journals (Sweden)

Hélio Belo

Full Text Available Fanconi anaemia (FA is an inherited disorder characterized by chromosomal instability. The phenotype is variable, which raises the possibility that it may be affected by other factors, such as epigenetic modifications. These play an important role in oncogenesis and may be pharmacologically manipulated. Our aim was to explore whether the epigenetic profiles in FA differ from non-FA individuals and whether these could be manipulated to alter the disease phenotype. We compared expression of epigenetic genes and DNA methylation profile of tumour suppressor genes between FA and normal samples. FA samples exhibited decreased expression levels of genes involved in epigenetic regulation and hypomethylation in the promoter regions of tumour suppressor genes. Treatment of FA cells with histone deacetylase inhibitor Vorinostat increased the expression of DNM3Tβ and reduced the levels of CIITA and HDAC9, PAK1, USP16, all involved in different aspects of epigenetic and immune regulation. Given the ability of Vorinostat to modulate epigenetic genes in FA patients, we investigated its functional effects on the FA phenotype. This was assessed by incubating FA cells with Vorinostat and quantifying chromosomal breaks induced by DNA cross-linking agents. Treatment of FA cells with Vorinostat resulted in a significant reduction of aberrant cells (81% on average. Our results suggest that epigenetic mechanisms may play a role in oncogenesis in FA. Epigenetic agents may be helpful in improving the phenotype of FA patients, potentially reducing tumour incidence in this population.

The political implications of epigenetics.

Science.gov (United States)

Robison, Shea K

2016-01-01

Epigenetics, which is just beginning to attract public attention and policy discussion, challenges conventional understanding of gene-environment interaction and intergenerational inheritance and perhaps much more besides. Does epigenetics challenge modern political ideologies? I analyzed the narratives of obesity and epigenetics recently published in the more liberal New York Times and the more conservative Wall Street Journal. For the years 2010 through 2014, 50 articles on obesity and 29 articles on epigenetics were identified, and elements in their causal narratives were quantitatively analyzed using a well described narrative policy framework. The narratives on obesity aligned with the two newspapers' reputed ideologies. However, the narratives on epigenetics aligned with neither ideology but freely mixed liberal and conservative elements. This small study may serve as a starting point for broader studies of epigenetics as it comes to affect political ideologies and, in turn, public policies. The narrative mix reported here could yet prove vulnerable to ideological capture, or, more optimistically, could portend the emergence of a "third-way" narrative using epigenetics to question atomistic individualism and allowing for less divisiveness in public-health domains such as obesity.

Target‐specific epigenetic silencing of endogenous retroviruses in mammals

DEFF Research Database (Denmark)

Wolf, Gernot

factors, have evolved to recognise and restrict ERVs in a target-specific manner. During his studies, Gernot Wolf investigated evolutionary and mechanistic aspects of epigenetic ERV restriction in various mammalian species. The studies included genome-wide transcription factor binding analysis using next...

The danger of epigenetics misconceptions (epigenetics and stuff…).

Science.gov (United States)

Georgel, Philippe T

2015-12-01

Within the past two decades, the fields of chromatin structure and function and transcription regulation research started to fuse and overlap, as evidence mounted to support a very strong regulatory role in gene expression that was associated with histone post-translational modifications, DNA methylation, as well as various chromatin-associated proteins (the pillars of the "Epigenetics" building). The fusion and convergence of these complementary fields is now often simply referred to as "Epigenetics". During these same 20 years, numerous new research groups have started to recognize the importance of chromatin composition, conformation, and its plasticity. However, as the field started to grow exponentially, its growth came with the spreading of several important misconceptions, which have unfortunately led to improper or hasty conclusions. The goal of this short "opinion" piece is to attempt to minimize future misinterpretations of experimental results and ensure that the right sets of experiment are used to reach the proper conclusion, at least as far as epigenetic mechanisms are concerned.

Conference Scene: epigenetics eh! The first formal meeting of the Canadian epigenetics community.

Science.gov (United States)

Underhill, Alan; Hendzel, Michael J

2011-08-01

In recognition of Canada's longstanding interest in epigenetics - and a particular linguistic interjection - the inaugural 'Epigenetics, Eh!' conference was held between 4-7 May 2011 in London, Ontario. The meeting struck an excellent balance between Canadian and international leaders in epigenetic research while also providing a venue to showcase up-and-coming talent. Almost without exception, presentations touched on the wide-ranging and severe consequences of epigenetic dysfunction, as well as current and emerging therapeutic opportunities. While gaining a deeper understanding of how DNA and histone modifications, together with multiple classes of ncRNAs, act to functionalize our genome, participants were also provided with a glimpse of the astounding complexity of chromatin structure, challenging existing dogma.

Epigenetics as a basis for diagnosis of neurodevelopmental disorders: challenges and opportunities.

Science.gov (United States)

Kubota, Takeo; Miyake, Kunio; Hariya, Natsuyo; Mochizuki, Kazuki

2014-07-01

Neurodevelopmental disorders, such as autism, are complex entities that can be caused by biological and social factors. In a subset of patients with congenital neurodevelopmental disorders, clear diagnosis can be achieved using DNA sequence-based analysis to identify changes in the DNA sequence (genetic variation). However, it has recently become clear that changes to the secondary modifications of DNA and histone structures (epigenetic variation) can also cause neurodevelopmental disorders via alteration of neural gene function. Moreover, it has recently been demonstrated that epigenetic modifications are more susceptible to alterations induced by environmental factors than are DNA sequences, and that some drugs commonly used reverse mental-stress induced alterations to histone modifications in neural genes. Therefore, application of diagnostic assays to detect epigenetic alterations will provide new insight into the characterization and treatment of neurodevelopmental disorders.

Congenital dyserythropoiesis with intererythroblastic chromatin bridges and ultrastructurally-normal erythroblast heterochromatin: a new disorder.

Science.gov (United States)

Wickramasinghe, S N; Spearing, R L; Hill, G R

1998-12-01

Two non-anaemic subjects, a father and daughter, with a new form of congenital dyserythropoiesis are reported. The features of their disorder are: (1) an abnormal blood film with basophilic stippling of red cells and oval macrocytes, (2) various dysplastic changes in the erythroblasts, including internuclear chromatin bridges, (3) ultrastructurally-normal erythroblast heterochromatin, (4) normal serum thymidine kinase activity, and (5) a probable autosomal dominant inheritance. The last three features distinguish this disorder from CDA type I.

Epigenetic Modifications and Potential New Treatment Targets in Diabetic Retinopathy

Directory of Open Access Journals (Sweden)

Lorena Perrone

2014-01-01

Full Text Available Retinopathy is a debilitating vascular complication of diabetes. As with other diabetic complications, diabetic retinopathy (DR is characterized by the metabolic memory, which has been observed both in DR patients and in DR animal models. Evidences have provided that after a period of poor glucose control insulin or diabetes drug treatment fails to prevent the development and progression of DR even when good glycemic control is reinstituted (glucose normalization, suggesting a metabolic memory phenomenon. Recent studies also underline the role of epigenetic chromatin modifications as mediators of the metabolic memory. Indeed, epigenetic changes may lead to stable modification of gene expression, participating in DR pathogenesis. Moreover, increasing evidences suggest that environmental factors such as chronic hyperglycemia are implicated DR progression and may also affect the epigenetic state. Here we review recent findings demonstrating the key role of epigenetics in the progression of DR. Further elucidation of epigenetic mechanisms, acting both at the cis- and trans-chromatin structural elements, will yield new insights into the pathogenesis of DR and will open the way for the discovery of novel therapeutic targets to prevent DR progression.

Epigenetic Targets for Reversing Immune Defects Caused by Alcohol Exposure

Science.gov (United States)

Curtis, Brenda J.; Zahs, Anita; Kovacs, Elizabeth J.

2013-01-01

Alcohol consumption alters factors that modify gene expression without changing the DNA code (i.e., epigenetic modulators) in many organ systems, including the immune system. Alcohol enhances the risk for developing several serious medical conditions related to immune system dysfunction, including acute respiratory distress syndrome (ARDS), liver cancer, and alcoholic liver disease (ALD). Binge and chronic drinking also render patients more susceptible to many infectious pathogens and advance the progression of HIV infection by weakening both innate and adaptive immunity. Epigenetic mechanisms play a pivotal role in these processes. For example, alcohol-induced epigenetic variations alter the developmental pathways of several types of immune cells (e.g., granulocytes, macrophages, and T-lymphocytes) and through these and other mechanisms promote exaggerated inflammatory responses. In addition, epigenetic mechanisms may underlie alcohol’s ability to interfere with the barrier functions of the gut and respiratory systems, which also contribute to the heightened risk of infections. Better understanding of alcohol’s effects on these epigenetic processes may help researchers identify new targets for the development of novel medications to prevent or ameliorate alcohol’s detrimental effects on the immune system. PMID:24313169

Epigenetic Determinism in Science and Society.

Science.gov (United States)

Waggoner, Miranda R; Uller, Tobias

2015-04-03

The epigenetic "revolution" in science cuts across many disciplines, and it is now one of the fastest growing research areas in biology. Increasingly, claims are made that epigenetics research represents a move away from the genetic determinism that has been prominent both in biological research and in understandings of the impact of biology on society. We discuss to what extent an epigenetic framework actually supports these claims. We show that, in contrast to the received view, epigenetics research is often couched in language as deterministic as genetics research in both science and the popular press. We engage the rapidly emerging conversation about the impact of epigenetics on public discourse and scientific practice, and we contend that the notion of epigenetic determinism - or the belief that epigenetic mechanisms determine the expression of human traits and behaviors - matters for understandings of the influence of biology and society on population health.

Bioinformatics Tools for Genome-Wide Epigenetic Research.

Science.gov (United States)

Angarica, Vladimir Espinosa; Del Sol, Antonio

2017-01-01

Epigenetics play a central role in the regulation of many important cellular processes, and dysregulations at the epigenetic level could be the source of serious pathologies, such as neurological disorders affecting brain development, neurodegeneration, and intellectual disability. Despite significant technological advances for epigenetic profiling, there is still a need for a systematic understanding of how epigenetics shapes cellular circuitry, and disease pathogenesis. The development of accurate computational approaches for analyzing complex epigenetic profiles is essential for disentangling the mechanisms underlying cellular development, and the intricate interaction networks determining and sensing chromatin modifications and DNA methylation to control gene expression. In this chapter, we review the recent advances in the field of "computational epigenetics," including computational methods for processing different types of epigenetic data, prediction of chromatin states, and study of protein dynamics. We also discuss how "computational epigenetics" has complemented the fast growth in the generation of epigenetic data for uncovering the main differences and similarities at the epigenetic level between individuals and the mechanisms underlying disease onset and progression.

Epigenetics in breast and prostate cancer.

Science.gov (United States)

Wu, Yanyuan; Sarkissyan, Marianna; Vadgama, Jaydutt V

2015-01-01

Most recent investigations into cancer etiology have identified a key role played by epigenetics. Specifically, aberrant DNA and histone modifications which silence tumor suppressor genes or promote oncogenes have been demonstrated in multiple cancer models. While the role of epigenetics in several solid tumor cancers such as colorectal cancer are well established, there is emerging evidence that epigenetics also plays a critical role in breast and prostate cancer. In breast cancer, DNA methylation profiles have been linked to hormone receptor status and tumor progression. Similarly in prostate cancer, epigenetic patterns have been associated with androgen receptor status and response to therapy. The regulation of key receptor pathways and activities which affect clinical therapy treatment options by epigenetics renders this field high priority for elucidating mechanisms and potential targets. A new set of methylation arrays are now available to screen epigenetic changes and provide the cutting-edge tools needed to perform such investigations. The role of nutritional interventions affecting epigenetic changes particularly holds promise. Ultimately, determining the causes and outcomes from epigenetic changes will inform translational applications for utilization as biomarkers for risk and prognosis as well as candidates for therapy.

Adiposopathy and epigenetics: an introduction to obesity as a transgenerational disease.

Science.gov (United States)

Bays, Harold; Scinta, Wendy

2015-11-01

To examine the contribution of generational epigenetic dysregulation to the inception of obesity and its adiposopathic consequences. Sources for this review included searches of PubMed, Google Scholar, and international government/major association websites using terms including adiposity, adiposopathy, epigenetics, genetics, and obesity. Excessive energy storage in adipose tissue often results in fat cell and fat organ dysfunction, which may cause metabolic and fat mass disorders. The adverse clinical manifestations of obesity are not solely due to the amount of body fat (adiposity), but are also dependent on anatomical and functional perturbations (adiposopathy or 'sick fat'). This review describes extragenetic factors and genetic conditions that promote obesity. It also serves as an introduction to epigenetic dysregulation (i.e., abnormalities in gene expression that occur without alteration in the genetic code itself), which may contribute to obesity and adiposopathic metabolic health outcomes in offspring. Within the epigenetic paradigm, obesity is a transgenerational disease, with weight lost or gained by either parent potentially impacting generational risk for obesity and its complications. Epigenetics may be an important contributor to the emergence of obesity and its complications as global epidemics. Although transgenerational epigenetic influences present challenges, they may also present interventional opportunities, via justifying weight management for individuals before, during, and after pregnancy and for future generations.

Environment, epigenetics and reproduction.

Science.gov (United States)

Skinner, Michael K

2017-07-01

A conference summary of the third biannual Kenya Africa Conference "Environment, Epigenetics and Reproduction" is provided. A partial special Environmental Epigenetics issue containing a number of papers in Volume 3, Issue 3 and 4 are discussed.

Epigenetics of psoriatic disease: A systematic review and critical appraisal.

Science.gov (United States)

Pollock, Remy A; Abji, Fatima; Gladman, Dafna D

2017-03-01

Psoriasis is an inflammatory disease of the skin that is sometimes accompanied by an auto-inflammatory arthritis called psoriatic arthritis (PsA). Psoriasis and PsA are multifactorial diseases that result from complex interactions of environmental and genetic risk factors. Epigenetic marks, which are labile chemical marks with diverse functions, form a layer of biological information that sits at the interface of genetics and the environment. Aberrant epigenetic regulation has been previously implicated in other rheumatological disorders. The purpose of this review is to summarize and critically evaluate the nascent literature on epigenetics in psoriasis and PsA. A systematic review yielded 52 primary articles after applying inclusion and exclusion criteria. Data were extracted using a standardized template and study quality assessed using a methodological quality checklist. Studies reflect a broad range of epigenetic sub-disciplines, the most common being DNA methylation, followed by the parent of origin effect or genomic imprinting, expression or activity of epigenetic modifying enzymes, and histone modifications. Epidemiological studies demonstrating excessive paternal transmission provided the earliest evidence of epigenetic deregulation in psoriatic disease, however few studies have examined its molecular mechanisms. Methylation studies evolved rapidly from low resolution global to targeted analyses of known psoriatic disease susceptibility loci such as HLA-C*0602. The recent explosion of epigenome-wide association studies has provided us with novel insights into psoriasis pathogenesis, and the mechanism of action of UVB, methotrexate, and anti-TNF therapies, as well as molecular signatures of psoriasis that may have clinical relevance. Finally, recent studies of pharmacological inhibitors of epigenetic modifier enzymes demonstrate their potential applicability as novel treatment modalities for psoriasis. Challenges of epigenetics research in psoriasis and Ps

Epigenetic Findings in Autism: New Perspectives for Therapy

Directory of Open Access Journals (Sweden)

James Jeffrey Bradstreet

2013-09-01

Full Text Available Autism and autism spectrum disorders (ASDs are complex neurodevelopmental disorders characterized by dysfunctions in social interactions, communications, restricted interests, and repetitive stereotypic behaviors. Despite extensive genetic and biological research, significant controversy surrounds our understanding of the specific mechanisms of their pathogenesis. However, accumulating evidence points to the involvement of epigenetic modifications as foundational in creating ASD pathophysiology. Epigenetic modifications or the alteration of DNA transcription via variations in DNA methylation and histone modifications but without alterations in the DNA sequence, affect gene regulation. These alterations in gene expression, obtained through DNA methylation and/or histone modifications, result from transcriptional regulatory influences of environmental factors, such as nutritional deficiencies, various toxicants, immunological effects, and pharmaceuticals. As such these effects are epigenetic regulators which determine the final biochemistry and physiology of the individual. In contrast to psychopharmacological interventions, bettering our understanding of how these gene-environmental interactions create autistic symptoms should facilitate the development of therapeutic targeting of gene expression for ASD biomedical care.

Dissecting epigenetic silencing complexity in the mouse lung cancer suppressor gene Cadm1.

Directory of Open Access Journals (Sweden)

Stella Marie Reamon-Buettner

Full Text Available Disease-oriented functional analysis of epigenetic factors and their regulatory mechanisms in aberrant silencing is a prerequisite for better diagnostics and therapy. Yet, the precise mechanisms are still unclear and complex, involving the interplay of several effectors including nucleosome positioning, DNA methylation, histone variants and histone modifications. We investigated the epigenetic silencing complexity in the tumor suppressor gene Cadm1 in mouse lung cancer progenitor cell lines, exhibiting promoter hypermethylation associated with transcriptional repression, but mostly unresponsive to demethylating drug treatments. After predicting nucleosome positions and transcription factor binding sites along the Cadm1 promoter, we carried out single-molecule mapping with DNA methyltransferase M.SssI, which revealed in silent promoters high nucleosome occupancy and occlusion of transcription factor binding sites. Furthermore, M.SssI maps of promoters varied within and among the different lung cancer cell lines. Chromatin analysis with micrococcal nuclease also indicated variations in nucleosome positioning to have implications in the binding of transcription factors near nucleosome borders. Chromatin immunoprecipitation showed that histone variants (H2A.Z and H3.3, and opposing histone modification marks (H3K4me3 and H3K27me3 all colocalized in the same nucleosome positions that is reminiscent of epigenetic plasticity in embryonic stem cells. Altogether, epigenetic silencing complexity in the promoter region of Cadm1 is not only defined by DNA hypermethylation, but high nucleosome occupancy, altered nucleosome positioning, and 'bivalent' histone modifications, also likely contributed in the transcriptional repression of this gene in the lung cancer cells. Our results will help define therapeutic intervention strategies using epigenetic drugs in lung cancer.

At the Frontier of Epigenetics of Brain Sex Differences

Directory of Open Access Journals (Sweden)

Margaret M Mccarthy

2015-08-01

Full Text Available The notion that epigenetics may play an important role in the establishment and maintenance of sex differences in the brain has garnered great enthusiasm but the reality in terms of actual advances have been slow. Two general approaches include the comparison of a particular epigenetic mark in males versus females and the inhibition of key epigenetic enzymes or co-factors to determine if this eliminates a particular sex difference in brain or behavior. The majority of emphasis has been on candidate genes such as steroid receptors. Only recently have more generalized survey type approaches been achieved and these promise to open new vista’s and accelerate discovery of important roles for DNA methylation, histone modification and microRNAs. Technical challenges abound and while not unique to this field will require novel thinking and new approaches by behavioral neuroendocrinogists.

Prenatal nutrition, epigenetics and schizophrenia risk: can we test causal effects?

Science.gov (United States)

Kirkbride, James B; Susser, Ezra; Kundakovic, Marija; Kresovich, Jacob K; Davey Smith, George; Relton, Caroline L

2012-06-01

We posit that maternal prenatal nutrition can influence offspring schizophrenia risk via epigenetic effects. In this article, we consider evidence that prenatal nutrition is linked to epigenetic outcomes in offspring and schizophrenia in offspring, and that schizophrenia is associated with epigenetic changes. We focus upon one-carbon metabolism as a mediator of the pathway between perturbed prenatal nutrition and the subsequent risk of schizophrenia. Although post-mortem human studies demonstrate DNA methylation changes in brains of people with schizophrenia, such studies cannot establish causality. We suggest a testable hypothesis that utilizes a novel two-step Mendelian randomization approach, to test the component parts of the proposed causal pathway leading from prenatal nutritional exposure to schizophrenia. Applied here to a specific example, such an approach is applicable for wider use to strengthen causal inference of the mediating role of epigenetic factors linking exposures to health outcomes in population-based studies.

Epigenetic remodeling and modification to preserve skeletogenesis in vivo.

Science.gov (United States)

Godfrey, Tanner C; Wildman, Benjamin J; Javed, Amjad; Lengner, Christopher J; Hassan, Mohammad Quamarul

2018-12-01

Current studies offer little insight on how epigenetic remodeling of bone-specific chromatin maintains bone mass in vivo. Understanding this gap and precise mechanism is pivotal for future therapeutic innovation to prevent bone loss. Recently, we found that low bone mass is associated with decreased H3K27 acetylation (activating histone modification) of bone specific gene promoters. Here, we aim to elucidate the epigenetic mechanisms by which a miRNA cluster controls bone synthesis and homeostasis by regulating chromatin accessibility and H3K27 acetylation. In order to decipher the epigenetic axis that regulates osteogenesis, we studied a drug inducible anti-miR-23a cluster (miR-23a Cl ZIP ) knockdown mouse model. MiR-23a cluster knockdown (heterozygous) mice developed high bone mass. These mice displayed increased expression of Runx2 and Baf45a, essential factors for skeletogenesis; and decreased expression of Ezh2, a chromatin repressor indispensable for skeletogenesis. ChIP assays using miR-23a Cl knockdown calvarial cells revealed a BAF45A-EZH2 epigenetic antagonistic mechanism that maintains bone formation. Together, our findings support that the miR-23a Cl connection with tissue-specific RUNX2-BAF45A-EZH2 function is a novel molecular epigenetic axis through which a miRNA cluster orchestrates chromatin modification to elicit major effects on osteogenesis in vivo.

Epigenetic regulation in the inner ear and its potential roles in development, protection, and regeneration

Directory of Open Access Journals (Sweden)

Jian eZuo

2015-01-01

Full Text Available The burgeoning field of epigenetics is beginning to make a significant impact on our understanding of tissue development, maintenance, and function. Epigenetic mechanisms regulate the structure and activity of the genome in response to intracellular and environmental cues that direct cell-type specific gene networks. The inner ear is comprised of highly specialized cell types with identical genomes that originate from a single totipotent zygote. During inner ear development specific combinations of transcription factors and epigenetic modifiers must function in a coordinated manner to establish and maintain cellular identity. These epigenetic regulatory mechanisms contribute to the maintenance of distinct chromatin states and cell-type specific gene expression patterns. In this review, we highlight emerging paradigms for epigenetic modifications related to inner ear development, and how epigenetics may have a significant role in hearing loss, protection, and regeneration.

Epigenetic Therapy in Lung Cancer

Directory of Open Access Journals (Sweden)

Stephen V Liu

2013-05-01

Full Text Available Epigenetic dysregulation of gene function has been strongly implicated in carcinogenesis and is one of the mechanisms contributing to the development of lung cancer. The inherent reversibility of epigenetic alterations makes them viable therapeutic targets. Here, we review the therapeutic implications of epigenetic changes in lung cancer, and recent advances in therapeutic strategies targeting DNA methylation and histone acetylation.

Ancient evolutionary origins of epigenetic regulation associated with posttraumatic stress disorder

Directory of Open Access Journals (Sweden)

Levent eSipahi

2014-05-01

Full Text Available Epigenetic marks, including DNA methylation, are modifiable molecular factors that may underlie mental disorders, especially responses to trauma, including the development of and resilience to posttraumatic stress disorder (PTSD. Previous work has identified differential DNA methylation at CpG dinucleotide sites genomewide between trauma exposed individuals with and without PTSD, suggesting a role for epigenetic potential – the capacity to epigenetically regulate behavior and physiology in response to lived experiences. The human species is characterized by an increased period of adaptive plasticity during brain development. The evolutionary history of epigenetic potential in relation to adaptive plasticity is currently unknown. Using phylogenetic methods and functional annotation analyses, we trace the evolution of over 7,000 CpG dinucleotides, including 203 associated with PTSD, during the descent of humans in during mammalian evolution and characterize the biological significance of this evolution. We demonstrate that few (7% PTSD-associated CpG sites are unique to humans, while the vast majority of sites have deep evolutionary origins: 73% and 93% were unambiguously present in the last common ancestor of humans/orangutans and humans/chimpanzees, respectively. Genes proximal to evolved PTSD-associated CpG sites revealed significant enrichment for immune function during recent human evolution and regulation of gene expression during more ancient periods of human evolution. Additionally, 765 putative transcription factor binding sites (TFBS were identified that overlap with PTSD-associated CpG sites. Elucidation of the evolutionary history of PTSD-associated CpG sites may provide insights into the function and origin of epigenetic potential in trauma responses, generally, and PTSD, specifically. The human capacity to respond to trauma with stable physiologic and behavioral changes may be due to epigenetic potentials that are shared among many

Epigenetic Modifications: Therapeutic Potential in Cancer

Directory of Open Access Journals (Sweden)

Manisha Sachan

2015-08-01

Full Text Available Epigenetic modifications and alterations in chromatin structure and function contribute to the cumulative changes observed as normal cells undergo malignant transformation. These modifications and enzymes (DNA methyltransferases, histone deacetylases, histone methyltransferases, and demethylases related to them have been deeply studied to develop new drugs, epigenome-targeted therapies and new diagnostic tools. Epigenetic modifiers aim to restore normal epigenetic modification patterns through the inhibition of epigenetic modifier enzymes. Four of them (azacitidine, decitabine, vorinostat and romidepsin are approved by the U.S. Food and Drug Administration. This article provides an overview about the known functional roles of epigenetic enzymes in cancer development.

Epigenetic dynamics across the cell cycle

DEFF Research Database (Denmark)

Kheir, Tony Bou; Lund, Anders H.

2010-01-01

Progression of the mammalian cell cycle depends on correct timing and co-ordination of a series of events, which are managed by the cellular transcriptional machinery and epigenetic mechanisms governing genome accessibility. Epigenetic chromatin modifications are dynamic across the cell cycle...... a correct inheritance of epigenetic chromatin modifications to daughter cells. In this chapter, we summarize the current knowledge on the dynamics of epigenetic chromatin modifications during progression of the cell cycle....

Chromocentre integrity and epigenetic marks

Czech Academy of Sciences Publication Activity Database

Harničarová, Andrea; Galiová-Šustáčková, Gabriela; Legartová, Soňa; Kozubek, Stanislav; Matula, P.; Bártová, Eva

2010-01-01

Roč. 169, č. 1 (2010), s. 124-133 ISSN 1047-8477 R&D Projects: GA MŠk ME 919; GA MŠk(CZ) LC06027; GA MŠk(CZ) LC535 Grant - others:GA MŠk(CZ) ME919 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : SUV39h * histone methylation * epigenetics Subject RIV: BO - Biophysics Impact factor: 3.497, year: 2010

Genetic and Epigenetic Inactivation of Kruppel-like Factor 4 in Medulloblastoma

Directory of Open Access Journals (Sweden)

Yukiko Nakahara

2010-01-01

Full Text Available Although medulloblastoma is the most common pediatric malignant brain tumor, its molecular underpinnings are largely unknown. We have identified rare, recurrent homozygous deletions of Kruppel-like Factor 4 (KLF4 in medulloblastoma using high-resolution single nucleotide polymorphism arrays, digital karyotyping, and genomic real-time polymerase chain reaction (PCR. Furthermore, we show that there is loss of physiological KLF4 expression in more than 40% of primary medulloblastomas both at the RNA and protein levels. Medulloblastoma cell lines drastically increase the expression of KLF4 in response to the demethylating agent 5-azacytidine and demonstrate dense methylation of the promoter CpG island by bisulfite sequencing. Methylation-specific PCR targeting the KLF4 promoter demonstrates CpG methylation in approximately 16% of primary medulloblastomas. Reexpression of KLF4 in the D283 medulloblastoma cell line results in significant growth suppression both in vitro and in vivo. We conclude that KLF4 is inactivated by either genetic or epigenetic mechanisms in a large subset of medulloblastomas and that it likely functions as a tumor suppressor gene in the pathogenesis of medulloblastoma.

Major satellite repeat RNA stabilize heterochromatin retention of Suv39h enzymes by RNA-nucleosome association and RNA

NARCIS (Netherlands)

Camacho, Oscar Velazquez; Galan, Carmen; Swist-Rosowska, Kalina; Ching, Reagan; Gamalinda, Michael; Karabiber, Fethullah; La Rosa-Velazquez, De Inti; Engist, Bettina; Koschorz, Birgit; Shukeir, Nicholas; Onishi-Seebacher, Megumi; De Nobelen, Van Suzanne; Jenuwein, Thomas

2017-01-01

The Suv39h1 and Suv39h2 histone lysine methyltransferases are hallmark enzymes at mammalian heterochromatin. We show here that the mouse Suv39h2 enzyme differs from Suv39h1 by containing an N-terminal basic domain that facilitates retention at mitotic chromatin and provides an additional affinity

Molecular cloning and characterization of satellite DNA sequences from constitutive heterochromatin of the habu snake (Protobothrops flavoviridis, Viperidae) and the Burmese python (Python bivittatus, Pythonidae).

Science.gov (United States)

Matsubara, Kazumi; Uno, Yoshinobu; Srikulnath, Kornsorn; Seki, Risako; Nishida, Chizuko; Matsuda, Yoichi

2015-12-01

Highly repetitive DNA sequences of the centromeric heterochromatin provide valuable molecular cytogenetic markers for the investigation of genomic compartmentalization in the macrochromosomes and microchromosomes of sauropsids. Here, the relationship between centromeric heterochromatin and karyotype evolution was examined using cloned repetitive DNA sequences from two snake species, the habu snake (Protobothrops flavoviridis, Crotalinae, Viperidae) and Burmese python (Python bivittatus, Pythonidae). Three satellite DNA (stDNA) families were isolated from the heterochromatin of these snakes: 168-bp PFL-MspI from P. flavoviridis and 196-bp PBI-DdeI and 174-bp PBI-MspI from P. bivittatus. The PFL-MspI and PBI-DdeI sequences were localized to the centromeric regions of most chromosomes in the respective species, suggesting that the two sequences were the major components of the centromeric heterochromatin in these organisms. The PBI-MspI sequence was localized to the pericentromeric region of four chromosome pairs. The PFL-MspI and the PBI-DdeI sequences were conserved only in the genome of closely related species, Gloydius blomhoffii (Crotalinae) and Python molurus, respectively, although their locations on the chromosomes were slightly different. In contrast, the PBI-MspI sequence was also in the genomes of P. molurus and Boa constrictor (Boidae), and additionally localized to the centromeric regions of eight chromosome pairs in B. constrictor, suggesting that this sequence originated in the genome of a common ancestor of Pythonidae and Boidae, approximately 86 million years ago. The three stDNA sequences showed no genomic compartmentalization between the macrochromosomes and microchromosomes, suggesting that homogenization of the centromeric and/or pericentromeric stDNA sequences occurred in the macrochromosomes and microchromosomes of these snakes.

Epigenetic control of hypoxia inducible factor-1α-dependent expression of placental growth factor in hypoxic conditions.

Science.gov (United States)

Tudisco, Laura; Della Ragione, Floriana; Tarallo, Valeria; Apicella, Ivana; D'Esposito, Maurizio; Matarazzo, Maria Rosaria; De Falco, Sandro

2014-04-01

Hypoxia plays a crucial role in the angiogenic switch, modulating a large set of genes mainly through the activation of hypoxia-inducible factor (HIF) transcriptional complex. Endothelial cells play a central role in new vessels formation and express placental growth factor (PlGF), a member of vascular endothelial growth factor (VEGF) family, mainly involved in pathological angiogenesis. Despite several observations suggest a hypoxia-mediated positive modulation of PlGF, the molecular mechanism governing this regulation has not been fully elucidated. We decided to investigate if epigenetic modifications are involved in hypoxia-induced PlGF expression. We report that PlGF expression was induced in cultured human and mouse endothelial cells exposed to hypoxia (1% O 2), although DNA methylation at the Plgf CpG-island remains unchanged. Remarkably, robust hyperacetylation of histones H3 and H4 was observed in the second intron of Plgf, where hypoxia responsive elements (HREs), never described before, are located. HIF-1α, but not HIF-2α, binds to identified HREs. Noteworthy, only HIF-1α silencing fully inhibited PlGF upregulation. These results formally demonstrate a direct involvement of HIF-1α in the upregulation of PlGF expression in hypoxia through chromatin remodeling of HREs sites. Therefore, PlGF may be considered one of the putative targets of anti-HIF therapeutic applications.

Epigenetics, autism spectrum, and neurodevelopmental disorders.

Science.gov (United States)

Rangasamy, Sampathkumar; D'Mello, Santosh R; Narayanan, Vinodh

2013-10-01

Epigenetic marks are modifications of DNA and histones. They are considered to be permanent within a single cell during development, and are heritable across cell division. Programming of neurons through epigenetic mechanisms is believed to be critical in neural development. Disruption or alteration in this process causes an array of neurodevelopmental disorders, including autism spectrum disorders (ASDs). Recent studies have provided evidence for an altered epigenetic landscape in ASDs and demonstrated the central role of epigenetic mechanisms in their pathogenesis. Many of the genes linked to the ASDs encode proteins that are involved in transcriptional regulation and chromatin remodeling. In this review we highlight selected neurodevelopmental disorders in which epigenetic dysregulation plays an important role. These include Rett syndrome, fragile X syndrome, Prader-Willi syndrome, Angelman syndrome, and Kabuki syndrome. For each of these disorders, we discuss how advances in our understanding of epigenetic mechanisms may lead to novel therapeutic approaches.

The epigenetic landscape of age-related diseases: the geroscience perspective.

Science.gov (United States)

Gensous, Noémie; Bacalini, Maria Giulia; Pirazzini, Chiara; Marasco, Elena; Giuliani, Cristina; Ravaioli, Francesco; Mengozzi, Giacomo; Bertarelli, Claudia; Palmas, Maria Giustina; Franceschi, Claudio; Garagnani, Paolo

2017-08-01

In this review, we summarize current knowledge regarding the epigenetics of age-related diseases, focusing on those studies that have described DNA methylation landscape in cardio-vascular diseases, musculoskeletal function and frailty. We stress the importance of adopting the conceptual framework of "geroscience", which starts from the observation that advanced age is the major risk factor for several of these pathologies and aims at identifying the mechanistic links between aging and age-related diseases. DNA methylation undergoes a profound remodeling during aging, which includes global hypomethylation of the genome, hypermethylation at specific loci and an increase in inter-individual variation and in stochastic changes of DNA methylation values. These epigenetic modifications can be an important contributor to the development of age-related diseases, but our understanding on the complex relationship between the epigenetic signatures of aging and age-related disease is still poor. The most relevant results in this field come from the use of the so called "epigenetics clocks" in cohorts of subjects affected by age-related diseases. We report these studies in final section of this review.

EpiGeNet: A Graph Database of Interdependencies Between Genetic and Epigenetic Events in Colorectal Cancer.

Science.gov (United States)

Balaur, Irina; Saqi, Mansoor; Barat, Ana; Lysenko, Artem; Mazein, Alexander; Rawlings, Christopher J; Ruskin, Heather J; Auffray, Charles

2017-10-01

The development of colorectal cancer (CRC)-the third most common cancer type-has been associated with deregulations of cellular mechanisms stimulated by both genetic and epigenetic events. StatEpigen is a manually curated and annotated database, containing information on interdependencies between genetic and epigenetic signals, and specialized currently for CRC research. Although StatEpigen provides a well-developed graphical user interface for information retrieval, advanced queries involving associations between multiple concepts can benefit from more detailed graph representation of the integrated data. This can be achieved by using a graph database (NoSQL) approach. Data were extracted from StatEpigen and imported to our newly developed EpiGeNet, a graph database for storage and querying of conditional relationships between molecular (genetic and epigenetic) events observed at different stages of colorectal oncogenesis. We illustrate the enhanced capability of EpiGeNet for exploration of different queries related to colorectal tumor progression; specifically, we demonstrate the query process for (i) stage-specific molecular events, (ii) most frequently observed genetic and epigenetic interdependencies in colon adenoma, and (iii) paths connecting key genes reported in CRC and associated events. The EpiGeNet framework offers improved capability for management and visualization of data on molecular events specific to CRC initiation and progression.

Small RNA-Mediated Epigenetic Myostatin Silencing

Directory of Open Access Journals (Sweden)

Thomas C Roberts

2012-01-01

Full Text Available Myostatin (Mstn is a secreted growth factor that negatively regulates muscle mass and is therefore a potential pharmacological target for the treatment of muscle wasting disorders such as Duchenne muscular dystrophy. Here we describe a novel Mstn blockade approach in which small interfering RNAs (siRNAs complementary to a promoter-associated transcript induce transcriptional gene silencing (TGS in two differentiated mouse muscle cell lines. Silencing is sensitive to treatment with the histone deacetylase inhibitor trichostatin A, and the silent state chromatin mark H3K9me2 is enriched at the Mstn promoter following siRNA transfection, suggesting epigenetic remodeling underlies the silencing effect. These observations suggest that long-term epigenetic silencing may be feasible for Mstn and that TGS is a promising novel therapeutic strategy for the treatment of muscle wasting disorders.

Nutritional influences on epigenetic programming: asthma, allergy, and obesity.

Science.gov (United States)

Palmer, Debra J; Huang, Rae-Chi; Craig, Jeffrey M; Prescott, Susan L

2014-11-01

Observational studies show consistent links between early-life nutritional exposures as important risk factors for the development of asthma, allergy, and obesity. Reliance on increasing use of dietary supplementation and fortification (eg, with folate) to compensate for increased consumption of processed foods is also influencing immune and metabolic outcomes. Epigenetics is providing substantial advances in understanding how early-life nutritional exposures can effect disease development. This article summarizes current evidence linking the influence of early-life nutritional exposures on epigenetic regulation with a focus on the disease outcomes of asthma, allergy, and obesity. Copyright © 2014 Elsevier Inc. All rights reserved.

The multifaceted interplay between lipids and epigenetics.

Science.gov (United States)

Dekkers, Koen F; Slagboom, P Eline; Jukema, J Wouter; Heijmans, Bastiaan T

2016-06-01

The interplay between lipids and epigenetic mechanisms has recently gained increased interest because of its relevance for common diseases and most notably atherosclerosis. This review discusses recent advances in unravelling this interplay with a particular focus on promising approaches and methods that will be able to establish causal relationships. Complementary approaches uncovered close links between circulating lipids and epigenetic mechanisms at multiple levels. A characterization of lipid-associated genetic variants suggests that these variants exert their influence on lipid levels through epigenetic changes in the liver. Moreover, exposure of monocytes to lipids persistently alters their epigenetic makeup resulting in more proinflammatory cells. Hence, epigenetic changes can both impact on and be induced by lipids. It is the combined application of technological advances to probe epigenetic modifications at a genome-wide scale and methodological advances aimed at causal inference (including Mendelian randomization and integrative genomics) that will elucidate the interplay between circulating lipids and epigenetics. Understanding its role in the development of atherosclerosis holds the promise of identifying a new category of therapeutic targets, since epigenetic changes are amenable to reversal.

Merging data from genetic and epigenetic approaches to better understand autistic spectrum disorder.

Science.gov (United States)

Grayson, Dennis R; Guidotti, Alessandro

2016-01-01

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that is characterized by a wide range of cognitive and behavioral abnormalities. Genetic research has identified large numbers of genes that contribute to ASD phenotypes. There is compelling evidence that environmental factors contribute to ASD through influences that differentially impact the brain through epigenetic mechanisms. Both genetic mutations and epigenetic influences alter gene expression in different cell types of the brain. Mutations impact the expression of large numbers of genes and also have downstream consequences depending on specific pathways associated with the mutation. Environmental factors impact the expression of sets of genes by altering methylation/hydroxymethylation patterns, local histone modification patterns and chromatin remodeling. Herein, we discuss recent developments in the research of ASD with a focus on epigenetic pathways as a complement to current genetic screening.

Hypothesis: Genetic and epigenetic risk factors interact to modulate vulnerability and resilience to FASD

Directory of Open Access Journals (Sweden)

Elif eTunc-Ozcan

2014-08-01

Full Text Available Fetal alcohol spectrum disorder (FASD presents a collection of symptoms representing physiological and behavioral phenotypes caused by maternal alcohol consumption. Symptom severity is modified by genetic differences in fetal susceptibility and resistance as well as maternal genetic factors such as maternal alcohol sensitivity. Animal models demonstrate that both maternal and paternal genetics contribute to the variation in the fetus’ vulnerability to alcohol exposure. Maternal and paternal genetics define the variations in these phenotypes even without the effect of alcohol in utero, as most of these traits are polygenic, non-Mendelian, in their inheritance. In addition, the epigenetic alterations that instigate the alcohol induced neurodevelopmental deficits can interact with the polygenic inheritance of respective traits. Here, based on specific examples, we present the hypothesis that the principles of non-Mendelian inheritance, or ‘exceptions’ to Mendelian genetics, can be the driving force behind the severity of the prenatal alcohol-exposed individual’s symptomology. One such exception is when maternal alleles lead to an altered intrauterine hormonal environment and, therefore, produce variations in the long-term consequences on the development of the alcohol-exposed fetus. Another exception is when epigenetic regulation of allele-specific gene expression generates disequilibrium between the maternal versus paternal genetic contributions, and thereby, modifies the effect of prenatal alcohol exposure on the fetus. We propose that these situations in which one parent has an exaggerated influence over the offspring’s vulnerability to prenatal alcohol are major contributing mechanisms responsible for the variations in the symptomology of FASD in the exposed generation and beyond.

The environmental roots of non-communicable diseases (NCDs) and the epigenetic impacts of globalization.

Science.gov (United States)

Vineis, Paolo; Stringhini, Silvia; Porta, Miquel

2014-08-01

Non-communicable diseases (NCDs) are increasing worldwide. We hypothesize that environmental factors (including social adversity, diet, lack of physical activity and pollution) can become "embedded" in the biology of humans. We also hypothesize that the "embedding" partly occurs because of epigenetic changes, i.e., durable changes in gene expression patterns. Our concern is that once such factors have a foundation in human biology, they can affect human health (including NCDs) over a long period of time and across generations. To analyze how worldwide changes in movements of goods, persons and lifestyles (globalization) may affect the "epigenetic landscape" of populations and through this have an impact on NCDs. We provide examples of such changes and effects by discussing the potential epigenetic impact of socio-economic status, migration, and diet, as well as the impact of environmental factors influencing trends in age at puberty. The study of durable changes in epigenetic patterns has the potential to influence policy and practice; for example, by enabling stratification of populations into those who could particularly benefit from early interventions to prevent NCDs, or by demonstrating mechanisms through which environmental factors influence disease risk, thus providing compelling evidence for policy makers, companies and the civil society at large. The current debate on the '25 × 25 strategy', a goal of 25% reduction in relative mortality from NCDs by 2025, makes the proposed approach even more timely. Epigenetic modifications related to globalization may crucially contribute to explain current and future patterns of NCDs, and thus deserve attention from environmental researchers, public health experts, policy makers, and concerned citizens. Copyright © 2014 Elsevier Inc. All rights reserved.

Epigenetics and depression: return of the repressed.

Science.gov (United States)

Dalton, Victoria S; Kolshus, Erik; McLoughlin, Declan M

2014-02-01

Epigenetics has recently emerged as a potential mechanism by which adverse environmental stimuli can result in persistent changes in gene expression. Epigenetic mechanisms function alongside the DNA sequence to modulate gene expression and ultimately influence protein production. The current review provides an introduction and overview of epigenetics with a particular focus on preclinical and clinical studies relevant to major depressive disorder (MDD). PubMed and Web of Science databases were interrogated from January 1995 up to December 2012 using combinations of search terms, including "epigenetic", "microRNA" and "DNA methylation" cross referenced with "depression", "early life stress" and "antidepressant". There is an association between adverse environmental stimuli, such as early life stress, and epigenetic modification of gene expression. Epigenetic changes have been reported in humans with MDD and may serve as biomarkers to improve diagnosis. Antidepressant treatments appear to reverse or initiate compensatory epigenetic alterations that may be relevant to their mechanism of action. As a narrative review, the current report was interpretive and qualitative in nature. Epigenetic modification of gene expression provides a mechanism for understanding the link between long-term effects of adverse life events and the changes in gene expression that are associated with depression. Although still a developing field, in the future, epigenetic modifications of gene expression may provide novel biomarkers to predict future susceptibility and/or onset of MDD, improve diagnosis, and aid in the development of epigenetics-based therapies for depression. © 2013 Published by Elsevier B.V.

Reversible dual inhibitor against G9a and DNMT1 improves human iPSC derivation enhancing MET and facilitating transcription factor engagement to the genome.

Directory of Open Access Journals (Sweden)

Juan Roberto Rodriguez-Madoz

Full Text Available The combination of defined factors with small molecules targeting epigenetic factors is a strategy that has been shown to enhance optimal derivation of iPSCs and could be used for disease modelling, high throughput screenings and/or regenerative medicine applications. In this study, we showed that a new first-in-class reversible dual G9a/DNMT1 inhibitor compound (CM272 improves the efficiency of human cell reprogramming and iPSC generation from primary cells of healthy donors and patient samples, using both integrative and non-integrative methods. Moreover, CM272 facilitates the generation of human iPSC with only two factors allowing the removal of the most potent oncogenic factor cMYC. Furthermore, we demonstrated that mechanistically, treatment with CM272 induces heterochromatin relaxation, facilitates the engagement of OCT4 and SOX2 transcription factors to OSKM refractory binding regions that are required for iPSC establishment, and enhances mesenchymal to epithelial transition during the early phase of cell reprogramming. Thus, the use of this new G9a/DNMT reversible dual inhibitor compound may represent an interesting alternative for improving cell reprogramming and human iPSC derivation for many different applications while providing interesting insights into reprogramming mechanisms.

Reversible dual inhibitor against G9a and DNMT1 improves human iPSC derivation enhancing MET and facilitating transcription factor engagement to the genome.

Science.gov (United States)

Rodriguez-Madoz, Juan Roberto; San Jose-Eneriz, Edurne; Rabal, Obdulia; Zapata-Linares, Natalia; Miranda, Estibaliz; Rodriguez, Saray; Porciuncula, Angelo; Vilas-Zornoza, Amaia; Garate, Leire; Segura, Victor; Guruceaga, Elizabeth; Agirre, Xabier; Oyarzabal, Julen; Prosper, Felipe

2017-01-01

The combination of defined factors with small molecules targeting epigenetic factors is a strategy that has been shown to enhance optimal derivation of iPSCs and could be used for disease modelling, high throughput screenings and/or regenerative medicine applications. In this study, we showed that a new first-in-class reversible dual G9a/DNMT1 inhibitor compound (CM272) improves the efficiency of human cell reprogramming and iPSC generation from primary cells of healthy donors and patient samples, using both integrative and non-integrative methods. Moreover, CM272 facilitates the generation of human iPSC with only two factors allowing the removal of the most potent oncogenic factor cMYC. Furthermore, we demonstrated that mechanistically, treatment with CM272 induces heterochromatin relaxation, facilitates the engagement of OCT4 and SOX2 transcription factors to OSKM refractory binding regions that are required for iPSC establishment, and enhances mesenchymal to epithelial transition during the early phase of cell reprogramming. Thus, the use of this new G9a/DNMT reversible dual inhibitor compound may represent an interesting alternative for improving cell reprogramming and human iPSC derivation for many different applications while providing interesting insights into reprogramming mechanisms.

Health, wealth and behavioural change: an exploration of role responsibilities in the wake of epigenetics.

Science.gov (United States)

Vears, Danya F; D'Abramo, Flavio

2018-04-01

The field of epigenetics is leading to new conceptualizations of the role of environmental factors in health and genetic disease. Although more evidence is required, epigenetic mechanisms are being implicated in the link between low socioeconomic status and poor health status. Epigenetic phenomena work in a number of ways: they can be established early in development, transmitted from previous generations and/or responsive to environmental factors. Knowledge about these types of epigenetic traits might therefore allow us to move away from a genetic deterministic perspective, and provide individuals with the opportunity to change their health status. Although this could be equated with patient empowerment, it could also lead to stigmatization and discrimination where individuals are deemed responsible for their health, even if they are not in social situations where they are able to enact change that would alter their health status. In this paper, we will explore the responsibilities of different actors in the healthcare sphere in relation to epigenetics across four different contexts: (1) genetic research, (2) clinical practice, (3) prenatal care and (4) the workplace. Within this exploration of role responsibilities, we will also discuss the potential constraints that might prevent the patient, mother-to-be, research participant or employee, from enacting any necessary steps in order to increase their health status in response to epigenetic information.

Learning epigenetic regulation from mycobacteria

Directory of Open Access Journals (Sweden)

Sanjeev Khosla

2016-01-01

Full Text Available In a eukaryotic cell, the transcriptional fate of a gene is determined by the profile of the epigenetic modifications it is associated with and the conformation it adopts within the chromatin. Therefore, the function that a cell performs is dictated by the sum total of the chromatin organization and the associated epigenetic modifications of each individual gene in the genome (epigenome. As the function of a cell during development and differentiation is determined by its microenvironment, any factor that can alter this microenvironment should be able to alter the epigenome of a cell. In the study published in Nature Communications (Yaseen [2015] Nature Communications 6:8922 doi: 10.1038/ncomms9922, we show that pathogenic Mycobacterium tuberculosis has evolved strategies to exploit this pliability of the host epigenome for its own survival. We describe the identification of a methyltransferase from M. tuberculosis that functions to modulate the host epigenome by methylating a novel, non-canonical arginine, H3R42 in histone H3. In another study, we showed that the mycobacterial protein Rv2966c methylates cytosines present in non-CpG context within host genomic DNA upon infection. Proteins with ability to directly methylate host histones H3 at a novel lysine residue (H3K14 has also been identified from Legionella pnemophilia (RomA. All these studies indicate the use of non-canonical epigenetic mechanisms by pathogenic bacteria to hijack the host transcriptional machinery.

Epigenetic architecture and miRNA: reciprocal regulators

DEFF Research Database (Denmark)

Wiklund, Erik D; Kjems, Jørgen; Clark, Susan J

2010-01-01

Deregulation of epigenetic and microRNA (miRNA) pathways are emerging as key events in carcinogenesis. miRNA genes can be epigenetically regulated and miRNAs can themselves repress key enzymes that drive epigenetic remodeling. Epigenetic and miRNA functions are thus tightly interconnected......RNAs) are considered especially promising in clinical applications, and their biogenesis and function is a subject of active research. In this review, the current status of epigenetic miRNA regulation is summarized and future therapeutic prospects in the field are discussed with a focus on cancer....

Progression of Tubulointerstitial Fibrosis and the Chronic Kidney Disease Phenotype – Role of Risk Factors and Epigenetics

Directory of Open Access Journals (Sweden)

Timothy D. Hewitson

2017-08-01

Full Text Available Although the kidney has capacity to repair after mild injury, ongoing or severe damage results in scarring (fibrosis and an associated progressive loss of kidney function. However, despite its universal significance, evidence highlights a population based heterogeneity in the trajectory of chronic kidney disease (CKD in these patients. To explain the heterogeneity of the CKD phenotype requires an understanding of the relevant risk factors for fibrosis. These factors include both the extrinsic nature of injury, and intrinsic factors such as age, gender, genetics, and perpetual activation of fibroblasts through priming. In many cases an additional level of regulation is provided by epigenetic mechanisms which integrate the various pro-fibrotic and anti-fibrotic triggers in fibrogenesis. In this review we therefore examine the various molecular and structural changes of fibrosis, and how they are influenced by extrinsic and intrinsic factors. Our aim is to provide a unifying hypothesis to help explain the transition from acute to CKD.

Epigenetics and type II diabetes mellitus: underlying mechanisms of prenatal predisposition

Directory of Open Access Journals (Sweden)

J. David Sterns

2014-05-01

Full Text Available Type II diabetes mellitus (T2DM is a widespread metabolic disorder characterized by insulin resistance resulting in abnormally high blood glucose levels. While the onset of T2DM is known to be influenced by a number of genetic factors, emerging research has demonstrated the additional role of a variety of epigenetic mechanisms in the development of this disorder. Epigenetics relates to the heritable changes in gene expression that cannot be explained by simple variations in the primary DNA sequence and includes DNA methylation and histone modification. These changes impact many processes, including stem cell differentiation into pancreatic endocrine cells as well as normal β-cell function. Recent studies focusing on the effects of maternal health, specifically as it is affected by famine and hyperglycemia, have found possible mechanisms to explain the increased likelihood of the fetus developing risk factors such as altered atherogenic lipid profiles, increased obesity and BMI, as well as impaired glucose tolerance (IGT for the development of T2DM later in life. It is suggested that these epigenetic influences happen early during gestation and are less susceptible to the effects of postnatal environmental modification as was previously thought. Regardless, emerging research into epigenetic-based treatment approaches for T2DM are promising and offer yet another means by which to limit the impact of this global epidemic.

Epigenetic alterations of sedimentary rocks at deposits

International Nuclear Information System (INIS)

Komarova, G.V.; Kondrat'eva, I.A.; Zelenova, O.I.

1980-01-01

Notions are explained, and technique for studying epigenetic alterations of sedimentary rocks at uranium deposits is described. Main types of epigenetic transformations and their mineralogic-geochemical characteristics are considered. Rock alterations, accompanying uranium mineralization, can be related to 2 types: oxidation and reduction. The main mineralogic-geochemical property of oxidation transformations is epigenetic limonitization. Stratal limonitization in primary grey-coloured terrigenic rocks and in epigenetically reduced (pyritized) rocks, as well as in rock, subjected to epigenetic gleying, are characterized. Reduction type of epigenetic transformations is subdivided into sulphidic and non-sulphidic (gley) subtypes. Sulphidic transformations in grey-coloured terrigenic rocks with organic substance of carbonic row, in rocks, containing organic substance of oil row, sulphide transformations of sedimentary rocks, as well as gley transformations, are considered

Journal of Biosciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Biosciences. Subhash C Lakhotia. Articles written in Journal of Biosciences. Volume 29 Issue 3 September 2004 pp 219-224. Commentary: Epigenetics of heterochromatin · Subhash C Lakhotia · More Details Fulltext PDF. Volume 32 Issue 3 April 2007 pp 429-431. Foreword · Subhash C ...

Obesity and the reproductive system disorders: epigenetics as a potential bridge.

Science.gov (United States)

Crujeiras, Ana B; Casanueva, Felipe F

2015-01-01

Obesity and overweight are significantly involved in several reproductive pathologies contributing to infertility in men and women. In addition, several cancers of the reproductive system, such as endometrial, ovarian, breast, testicular and prostate cancers, are strongly influenced by obesity. However, the molecular mechanisms involved in the association between obesity and reproductive disorders remain unclear. Our proposal is to review the current scientific evidence regarding the effect of obesity-related factors as the core of the collective mechanisms directly and indirectly involved in the relationship between obesity and reproductive disorders, with a special and original focus on the effect of the obesity state microenvironment on the epigenetic profile as a reversible mechanistic link between obesity and the reproductive disorders. A PubMed search was performed using keywords related to obesity and adipose-related factors and epigenetics and associated with keywords related to reproduction. Full-text articles and abstracts in the English language published prior to 31 December 2013 were reviewed. The obesity state notably contributes to a reproductive dysfunction in both men and women, ranging from infertility to oncological outcomes. Several epidemiological and experimental studies demonstrate that factors secreted by the adipose tissue and gut in an obesity state can directly induce reproductive disturbances. Relevantly, these same factors are able to alter the epigenetic regulation of genes, a dynamic and reversible mechanism by which the organism responds to environmental pressures critical to the reproductive function. This review outlines the evidence showing that the association between the reproductive pathologies and obesity is not inevitable but is potentially preventable and reversible. The epigenetic marks related to obesity could constitute a therapeutic target for the reproductive disorders associated with obesity. © The Author 2014

Epigenetics in the Vascular Endothelium: Looking From a Different Perspective in the Epigenomics Era.

Science.gov (United States)

Yan, Matthew S; Marsden, Philip A

2015-11-01

Cardiovascular diseases are commonly thought to be complex, non-Mendelian diseases that are influenced by genetic and environmental factors. A growing body of evidence suggests that epigenetic pathways play a key role in vascular biology and might be involved in defining and transducing cardiovascular disease inheritability. In this review, we argue the importance of epigenetics in vascular biology, especially from the perspective of endothelial cell phenotype. We highlight and discuss the role of epigenetic modifications across the transcriptional unit of protein-coding genes, especially the role of intragenic chromatin modifications, which are underappreciated and not well characterized in the current era of genome-wide studies. Importantly, we describe the practical application of epigenetics in cardiovascular disease therapeutics. © 2015 American Heart Association, Inc.

Epigenetics reloaded: the single-cell revolution.

Science.gov (United States)

Bheda, Poonam; Schneider, Robert

2014-11-01

Mechanistically, how epigenetic states are inherited through cellular divisions remains an important open question in the chromatin field and beyond. Defining the heritability of epigenetic states and the underlying chromatin-based mechanisms within a population of cells is complicated due to cell heterogeneity combined with varying levels of stability of these states; thus, efforts must be focused toward single-cell analyses. The approaches presented here constitute the forefront of epigenetics research at the single-cell level using classic and innovative methods to dissect epigenetics mechanisms from the limited material available in a single cell. This review further outlines exciting future avenues of research to address the significance of epigenetic heterogeneity and the contributions of microfluidics technologies to single-cell isolation and analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dynamic epigenetic states of maize centromeres

Directory of Open Access Journals (Sweden)

Yalin eLiu

2015-10-01

Full Text Available The centromere is a specialized chromosomal region identified as the major constriction, upon which the kinetochore complex is formed, ensuring accurate chromosome orientation and segregation during cell division. The rapid evolution of centromere DNA sequence and the conserved centromere function are two contradictory aspects of centromere biology. Indeed, the sole presence of genetic sequence is not sufficient for centromere formation. Various dicentric chromosomes with one inactive centromere have been recognized. It has also been found that de novo centromere formation is common on fragments in which centromeric DNA sequences are lost. Epigenetic factors play important roles in centromeric chromatin assembly and maintenance. Nondisjunction of the supernumerary B chromosome early prophase of meiosis I requires an active centromere. This review discusses recent studies in maize about genetic and epigenetic elements regulating formation and maintenance of centromere chromatin, as well as centromere behavior in meiosis.

Exercise impacts brain-derived neurotrophic factor plasticity by engaging mechanisms of epigenetic regulation.

Science.gov (United States)

Gomez-Pinilla, F; Zhuang, Y; Feng, J; Ying, Z; Fan, G

2011-02-01

We have evaluated the possibility that the action of voluntary exercise on the regulation of brain-derived neurotrophic factor (BDNF), a molecule important for rat hippocampal learning, could involve mechanisms of epigenetic regulation. We focused the studies on the Bdnf promoter IV, as this region is highly responsive to neuronal activity. We have found that exercise stimulates DNA demethylation in Bdnf promoter IV, and elevates levels of activated methyl-CpG-binding protein 2, as well as BDNF mRNA and protein in the rat hippocampus. Chromatin immunoprecipitation assay showed that exercise increases acetylation of histone H3, and protein assessment showed that exercise elevates the ratio of acetylated :total for histone H3 but had no effects on histone H4 levels. Exercise also reduces levels of the histone deacetylase 5 mRNA and protein implicated in the regulation of the Bdnf gene [N.M. Tsankova et al. (2006)Nat. Neurosci., 9, 519-525], but did not affect histone deacetylase 9. Exercise elevated the phosphorylated forms of calcium/calmodulin-dependent protein kinase II and cAMP response element binding protein, implicated in the pathways by which neural activity influences the epigenetic regulation of gene transcription, i.e. Bdnf. These results showing the influence of exercise on the remodeling of chromatin containing the Bdnf gene emphasize the importance of exercise on the control of gene transcription in the context of brain function and plasticity. Reported information about the impact of a behavior, inherently involved in the daily human routine, on the epigenome opens exciting new directions and therapeutic opportunities in the war against neurological and psychiatric disorders. © 2010 The Authors. European Journal of Neuroscience © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Epigenetic regulation of neural stem cell property from embryo to adult

Directory of Open Access Journals (Sweden)

Naoya Murao

2016-03-01

Full Text Available Neural stem cells (NSCs have the ability to self-renew and give rise to neurons and glial cells (astrocytes and oligodendrocytes in the mammalian central nervous system. This multipotency is acquired by NSCs during development and is maintained throughout life. Proliferation, fate specification, and maturation of NSCs are regulated by both cell intrinsic and extrinsic factors. Epigenetic modification is a representative intrinsic factor, being involved in many biological aspects of central nervous system development and adult neurogenesis through the regulation of NSC dynamics. In this review, we summarize recent progress in the epigenetic regulation of NSC behavior in the embryonic and adult brain, with particular reference to DNA methylation, histone modification, and noncoding RNAs.

Probing the germline-dependence of epigenetic inheritance using artificial insemination in mice

Science.gov (United States)

Bohacek, Johannes; von Werdt, Sarah; Mansuy, Isabelle M.

2016-01-01

Abstract We developed a simple, noninvasive artificial insemination technique to study epigenetic germline inheritance in mice. This technique avoids interfering factors introduced by superovulation, surgery, in vitro culture or mating that can confound the transmission of acquired epigenetic information through the germline. Using a stress model, we demonstrate that our method is suited to test the causal involvement of the male germline in transmitting acquired information from father to offspring. PMID:29492284

Age-Associated Decrease of the Histone Methyltransferase SUV39H1 in HSC Perturbs Heterochromatin and B Lymphoid Differentiation

Directory of Open Access Journals (Sweden)

Dounia Djeghloul

2016-06-01

Full Text Available The capacity of hematopoietic stem cells (HSC to generate B lymphocytes declines with age, contributing to impaired immune function in the elderly. Here we show that the histone methyltransferase SUV39H1 plays an important role in human B lymphoid differentiation and that expression of SUV39H1 decreases with age in both human and mouse HSC, leading to a global reduction in H3K9 trimethylation and perturbed heterochromatin function. Further, we demonstrate that SUV39H1 is a target of microRNA miR-125b, a known regulator of HSC function, and that expression of miR-125b increases with age in human HSC. Overexpression of miR-125b and inhibition of SUV39H1 in young HSC induced loss of B cell potential. Conversely, both inhibition of miR-125 and enforced expression of SUV39H1 improved the capacity of HSC from elderly individuals to generate B cells. Our findings highlight the importance of heterochromatin regulation in HSC aging and B lymphopoiesis.

Environmental epigenetics: A promising venue for developing next-generation pollution biomonitoring tools in marine invertebrates.

Science.gov (United States)

Suarez-Ulloa, Victoria; Gonzalez-Romero, Rodrigo; Eirin-Lopez, Jose M

2015-09-15

Environmental epigenetics investigates the cause-effect relationships between specific environmental factors and the subsequent epigenetic modifications triggering adaptive responses in the cell. Given the dynamic and potentially reversible nature of the different types of epigenetic marks, environmental epigenetics constitutes a promising venue for developing fast and sensible biomonitoring programs. Indeed, several epigenetic biomarkers have been successfully developed and applied in traditional model organisms (e.g., human and mouse). Nevertheless, the lack of epigenetic knowledge in other ecologically and environmentally relevant organisms has hampered the application of these tools in a broader range of ecosystems, most notably in the marine environment. Fortunately, that scenario is now changing thanks to the growing availability of complete reference genome sequences along with the development of high-throughput DNA sequencing and bioinformatic methods. Altogether, these resources make the epigenetic study of marine organisms (and more specifically marine invertebrates) a reality. By building on this knowledge, the present work provides a timely perspective highlighting the extraordinary potential of environmental epigenetic analyses as a promising source of rapid and sensible tools for pollution biomonitoring, using marine invertebrates as sentinel organisms. This strategy represents an innovative, groundbreaking approach, improving the conservation and management of natural resources in the oceans. Copyright © 2015 Elsevier Ltd. All rights reserved.

Epigenetics in Paediatric Gastroenterology, Hepatology, and Nutrition: Present Trends and Future Perspectives.

Science.gov (United States)

Zilbauer, Matthias; Zellos, Aglaia; Heuschkel, Robert; Gasparetto, Marco; Kraiczy, Judith; Postberg, Jan; Greco, Luigi; Auricchio, Renata; Galatola, Martina; Embleton, Nicholas; Wirth, Stefan; Jenke, Andreas

2016-04-01

Epigenetics can be defined as stable, potentially heritable changes in the cellular phenotype caused by mechanisms other than alterations to the underlying DNA sequence. As such, any observed phenotypic changes including organ development, aging, and the occurrence of disease could be driven by epigenetic mechanisms in the presence of stable cellular DNA sequences. Indeed, with the exception of rare mutations, the human genome-sequence has remained remarkably stable over the past centuries. In contrast, substantial changes to our environment as part of our modern life style have not only led to a significant reduction of certain infectious diseases but also seen the exponential increase in complex traits including obesity and multifactorial diseases such as autoimmune disorders. It is becoming increasingly clear that epigenetic mechanisms operate at the interface between the genetic code and our environment, and a large body of existing evidence supports the importance of environmental factors such as diet and nutrition, infections, and exposure to toxins on human health. This seems to be particularly the case during vulnerable periods of human development such as pregnancy and early life. Importantly, as the first point of contact for many of such environmental factors including nutrition, the digestive system is being increasingly linked to a number of "modern" pathologies. In this review article, we aim to give a brief introduction to the basic molecular principals of epigenetics and provide a concise summary of the existing evidence for the role of epigenetic mechanisms in gastrointestinal health and disease, hepatology, and nutrition.

Peromyscus as a Mammalian Epigenetic Model

Directory of Open Access Journals (Sweden)

Kimberly R. Shorter

2012-01-01

Full Text Available Deer mice (Peromyscus offer an opportunity for studying the effects of natural genetic/epigenetic variation with several advantages over other mammalian models. These advantages include the ability to study natural genetic variation and behaviors not present in other models. Moreover, their life histories in diverse habitats are well studied. Peromyscus resources include genome sequencing in progress, a nascent genetic map, and >90,000 ESTs. Here we review epigenetic studies and relevant areas of research involving Peromyscus models. These include differences in epigenetic control between species and substance effects on behavior. We also present new data on the epigenetic effects of diet on coat-color using a Peromyscus model of agouti overexpression. We suggest that in terms of tying natural genetic variants with environmental effects in producing specific epigenetic effects, Peromyscus models have a great potential.

Transgenerational epigenetics: Inheritance of global cytosine methylation and methylation-related epigenetic markers in the shrub Lavandula latifolia.

Science.gov (United States)

Herrera, Carlos M; Alonso, Conchita; Medrano, Mónica; Pérez, Ricardo; Bazaga, Pilar

2018-04-01

The ecological and evolutionary significance of natural epigenetic variation (i.e., not based on DNA sequence variants) variation will depend critically on whether epigenetic states are transmitted from parents to offspring, but little is known on epigenetic inheritance in nonmodel plants. We present a quantitative analysis of transgenerational transmission of global DNA cytosine methylation (= proportion of all genomic cytosines that are methylated) and individual epigenetic markers (= methylation status of anonymous MSAP markers) in the shrub Lavandula latifolia. Methods based on parent-offspring correlations and parental variance component estimation were applied to epigenetic features of field-growing plants ('maternal parents') and greenhouse-grown progenies. Transmission of genetic markers (AFLP) was also assessed for reference. Maternal parents differed significantly in global DNA cytosine methylation (range = 21.7-36.7%). Greenhouse-grown maternal families differed significantly in global methylation, and their differences were significantly related to maternal origin. Methylation-sensitive amplified polymorphism (MSAP) markers exhibited significant transgenerational transmission, as denoted by significant maternal variance component of marker scores in greenhouse families and significant mother-offspring correlations of marker scores. Although transmission-related measurements for global methylation and MSAP markers were quantitatively lower than those for AFLP markers taken as reference, this study has revealed extensive transgenerational transmission of genome-wide global cytosine methylation and anonymous epigenetic markers in L. latifolia. Similarity of results for global cytosine methylation and epigenetic markers lends robustness to this conclusion, and stresses the value of considering both types of information in epigenetic studies of nonmodel plants. © 2018 Botanical Society of America.

Epigenetics and assisted reproductive technologies

DEFF Research Database (Denmark)

Pinborg, Anja; Loft, Anne; Romundstad, Liv Bente

2016-01-01

Epigenetic modification controls gene activity without changes in the DNA sequence. The genome undergoes several phases of epigenetic programming during gametogenesis and early embryo development coinciding with assisted reproductive technologies (ART) treatments. Imprinting disorders have been...

Toxoplasma gondii chromodomain protein 1 binds to heterochromatin and colocalises with centromeres and telomeres at the nuclear periphery.

Directory of Open Access Journals (Sweden)

Mathieu Gissot

Full Text Available BACKGROUND: Apicomplexan parasites are responsible for some of the most deadly parasitic diseases afflicting humans, including malaria and toxoplasmosis. These obligate intracellular parasites exhibit a complex life cycle and a coordinated cell cycle-dependant expression program. Their cell division is a coordinated multistep process. How this complex mechanism is organised remains poorly understood. METHODS AND FINDINGS: In this study, we provide evidence for a link between heterochromatin, cell division and the compartmentalisation of the nucleus in Toxoplasma gondii. We characterised a T. gondii chromodomain containing protein (named TgChromo1 that specifically binds to heterochromatin. Using ChIP-on-chip on a genome-wide scale, we report TgChromo1 enrichment at the peri-centromeric chromatin. In addition, we demonstrate that TgChromo1 is cell-cycle regulated and co-localised with markers of the centrocone. Through the loci-specific FISH technique for T. gondii, we confirmed that TgChromo1 occupies the same nuclear localisation as the peri-centromeric sequences. CONCLUSION: We propose that TgChromo1 may play a role in the sequestration of chromosomes at the nuclear periphery and in the process of T. gondii cell division.

Epigenetics: general characteristics and implications for oral health

Directory of Open Access Journals (Sweden)

Ji-Yun Seo

2015-02-01

Full Text Available Genetic information such as DNA sequences has been limited to fully explain mechanisms of gene regulation and disease process. Epigenetic mechanisms, which include DNA methylation, histone modification and non-coding RNAs, can regulate gene expression and affect progression of disease. Although studies focused on epigenetics are being actively investigated in the field of medicine and biology, epigenetics in dental research is at the early stages. However, studies on epigenetics in dentistry deserve attention because epigenetic mechanisms play important roles in gene expression during tooth development and may affect oral diseases. In addition, understanding of epigenetic alteration is important for developing new therapeutic methods. This review article aims to outline the general features of epigenetic mechanisms and describe its future implications in the field of dentistry.

Epigenetics and colorectal cancer pathogenesis.

Science.gov (United States)

Bardhan, Kankana; Liu, Kebin

2013-06-05

Colorectal cancer (CRC) develops through a multistage process that results from the progressive accumulation of genetic mutations, and frequently as a result of mutations in the Wnt signaling pathway. However, it has become evident over the past two decades that epigenetic alterations of the chromatin, particularly the chromatin components in the promoter regions of tumor suppressors and oncogenes, play key roles in CRC pathogenesis. Epigenetic regulation is organized at multiple levels, involving primarily DNA methylation and selective histone modifications in cancer cells. Assessment of the CRC epigenome has revealed that virtually all CRCs have aberrantly methylated genes and that the average CRC methylome has thousands of abnormally methylated genes. Although relatively less is known about the patterns of specific histone modifications in CRC, selective histone modifications and resultant chromatin conformation have been shown to act, in concert with DNA methylation, to regulate gene expression to mediate CRC pathogenesis. Moreover, it is now clear that not only DNA methylation but also histone modifications are reversible processes. The increased understanding of epigenetic regulation of gene expression in the context of CRC pathogenesis has led to development of epigenetic biomarkers for CRC diagnosis and epigenetic drugs for CRC therapy.

Epigenetics and Colorectal Cancer Pathogenesis

International Nuclear Information System (INIS)

Bardhan, Kankana; Liu, Kebin

2013-01-01

Colorectal cancer (CRC) develops through a multistage process that results from the progressive accumulation of genetic mutations, and frequently as a result of mutations in the Wnt signaling pathway. However, it has become evident over the past two decades that epigenetic alterations of the chromatin, particularly the chromatin components in the promoter regions of tumor suppressors and oncogenes, play key roles in CRC pathogenesis. Epigenetic regulation is organized at multiple levels, involving primarily DNA methylation and selective histone modifications in cancer cells. Assessment of the CRC epigenome has revealed that virtually all CRCs have aberrantly methylated genes and that the average CRC methylome has thousands of abnormally methylated genes. Although relatively less is known about the patterns of specific histone modifications in CRC, selective histone modifications and resultant chromatin conformation have been shown to act, in concert with DNA methylation, to regulate gene expression to mediate CRC pathogenesis. Moreover, it is now clear that not only DNA methylation but also histone modifications are reversible processes. The increased understanding of epigenetic regulation of gene expression in the context of CRC pathogenesis has led to development of epigenetic biomarkers for CRC diagnosis and epigenetic drugs for CRC therapy

Epigenetics and Colorectal Cancer Pathogenesis

Directory of Open Access Journals (Sweden)

Kebin Liu

2013-06-01

Full Text Available Colorectal cancer (CRC develops through a multistage process that results from the progressive accumulation of genetic mutations, and frequently as a result of mutations in the Wnt signaling pathway. However, it has become evident over the past two decades that epigenetic alterations of the chromatin, particularly the chromatin components in the promoter regions of tumor suppressors and oncogenes, play key roles in CRC pathogenesis. Epigenetic regulation is organized at multiple levels, involving primarily DNA methylation and selective histone modifications in cancer cells. Assessment of the CRC epigenome has revealed that virtually all CRCs have aberrantly methylated genes and that the average CRC methylome has thousands of abnormally methylated genes. Although relatively less is known about the patterns of specific histone modifications in CRC, selective histone modifications and resultant chromatin conformation have been shown to act, in concert with DNA methylation, to regulate gene expression to mediate CRC pathogenesis. Moreover, it is now clear that not only DNA methylation but also histone modifications are reversible processes. The increased understanding of epigenetic regulation of gene expression in the context of CRC pathogenesis has led to development of epigenetic biomarkers for CRC diagnosis and epigenetic drugs for CRC therapy.

Epigenetics and Colorectal Cancer Pathogenesis

Energy Technology Data Exchange (ETDEWEB)

Bardhan, Kankana; Liu, Kebin, E-mail: Kliu@gru.edu [Department of Biochemistry and Molecular Biology, Medical College of Georgia, and Cancer Center, Georgia Regents University, Augusta, GA 30912 (United States)

2013-06-05

Colorectal cancer (CRC) develops through a multistage process that results from the progressive accumulation of genetic mutations, and frequently as a result of mutations in the Wnt signaling pathway. However, it has become evident over the past two decades that epigenetic alterations of the chromatin, particularly the chromatin components in the promoter regions of tumor suppressors and oncogenes, play key roles in CRC pathogenesis. Epigenetic regulation is organized at multiple levels, involving primarily DNA methylation and selective histone modifications in cancer cells. Assessment of the CRC epigenome has revealed that virtually all CRCs have aberrantly methylated genes and that the average CRC methylome has thousands of abnormally methylated genes. Although relatively less is known about the patterns of specific histone modifications in CRC, selective histone modifications and resultant chromatin conformation have been shown to act, in concert with DNA methylation, to regulate gene expression to mediate CRC pathogenesis. Moreover, it is now clear that not only DNA methylation but also histone modifications are reversible processes. The increased understanding of epigenetic regulation of gene expression in the context of CRC pathogenesis has led to development of epigenetic biomarkers for CRC diagnosis and epigenetic drugs for CRC therapy.

Recent Findings in Alzheimer Disease and Nutrition Focusing on Epigenetics.

Science.gov (United States)

Athanasopoulos, Dimitrios; Karagiannis, George; Tsolaki, Magda

2016-09-01

Alzheimer disease (AD) is a chronic neurodegenerative disease with no effective cure so far. The current review focuses on the epigenetic mechanisms of AD and how nutrition can influence the course of this disease through regulation of gene expression, according to the latest scientific findings. The search strategy was the use of scientific databases such as PubMed and Scopus in order to find relative research or review articles published in the years 2012-2015. By showing the latest data of various nutritional compounds, this study aims to stimulate the scientific community to recognize the value of nutrition in this subject. Epigenetics is becoming a very attractive subject for researchers because it can shed light on unknown aspects of complex diseases like AD. DNA methylation, histone modifications, and microRNAs are the principal epigenetic mechanisms involved in AD pathophysiology. Nutrition is an environmental factor that is related to AD through epigenetic pathways. Vitamin B-12, for instance, can alter the one-carbon metabolism and thus interfere in the DNA methylation process. The research results might seem ambiguous about the clinical role of nutrition, but there is strengthening evidence that proper nutrition can not only change epigenetic biomarker levels but also prevent the development of late-onset AD and attenuate cognition deficit. Nutrition might grow to become a preventive and even therapeutic alternative against AD, especially if combined with other antidementia interventions, brain exercise, physical training, etc. Epigenetic biomarkers can be a very helpful tool to help researchers find the exact nutrients needed to create specific remedies, and perhaps the same biomarkers can be used even in patient screening in the future. © 2016 American Society for Nutrition.

Neurological and Epigenetic Implications of Nutritional Deficiencies on Psychopathology: Conceptualization and Review of Evidence

Science.gov (United States)

Liu, Jianghong; Zhao, Sophie R.; Reyes, Teresa

2015-01-01

In recent years, a role for epigenetic modifications in the pathophysiology of disease has received significant attention. Many studies are now beginning to explore the gene–environment interactions, which may mediate early-life exposure to risk factors, such as nutritional deficiencies and later development of behavioral problems in children and adults. In this paper, we review the current literature on the role of epigenetics in the development of psychopathology, with a specific focus on the potential for epigenetic modifications to link nutrition and brain development. We propose a conceptual framework whereby epigenetic modifications (e.g., DNA methylation) mediate the link between micro- and macro-nutrient deficiency early in life and brain dysfunction (e.g., structural aberration, neurotransmitter perturbation), which has been linked to development of behavior problems later on in life. PMID:26251900

Neurological and Epigenetic Implications of Nutritional Deficiencies on Psychopathology: Conceptualization and Review of Evidence

Directory of Open Access Journals (Sweden)

Jianghong Liu

2015-08-01

Full Text Available In recent years, a role for epigenetic modifications in the pathophysiology of disease has received significant attention. Many studies are now beginning to explore the gene–environment interactions, which may mediate early-life exposure to risk factors, such as nutritional deficiencies and later development of behavioral problems in children and adults. In this paper, we review the current literature on the role of epigenetics in the development of psychopathology, with a specific focus on the potential for epigenetic modifications to link nutrition and brain development. We propose a conceptual framework whereby epigenetic modifications (e.g., DNA methylation mediate the link between micro- and macro-nutrient deficiency early in life and brain dysfunction (e.g., structural aberration, neurotransmitter perturbation, which has been linked to development of behavior problems later on in life.

Epigenetic Patterns of PTSD: DNA Methylation In Serum of OIF/OEF Servicemembers

Science.gov (United States)

2011-01-01

also have no data on other relevant exposures which are known to affect DNA methylation , such as dietary factors ( folate , vitamin B12 intake), (54, 55...ANSI Std. Z39.18 W81XWH-08-2-0053 31 MAR 2008 - 31 DEC 2010Final01-01-2011 Epigenetic Patterns of PTSD: DNA Methylation in Serum of OIF/OEF...distribution unlimited PTSD, epigenetics, DNA methylation , cytokines, serum, pre-deployment, post-deployment Abstract on next page. 38 jrusiecki@usuhs.mil

Epigenetics: the language of the cell?

Science.gov (United States)

Huang, Biao; Jiang, Cizhong; Zhang, Rongxin

2014-02-01

Epigenetics is one of the most rapidly developing fields of biological research. Breakthroughs in several technologies have enabled the possibility of genome-wide epigenetic research, for example the mapping of human genome-wide DNA methylation. In addition, with the development of various high-throughput and high-resolution sequencing technologies, a large number of functional noncoding RNAs have been identified. Massive studies indicated that these functional ncRNA also play an important role in epigenetics. In this review, we gain inspiration from the recent proposal of the ceRNAs hypothesis. This hypothesis proposes that miRNAs act as a language of communication. Accordingly, we further deduce that all of epigenetics may functionally acquire such a unique language characteristic. In summary, various epigenetic markers may not only participate in regulating cellular processes, but they may also act as the intracellular 'language' of communication and are involved in extensive information exchanges within cell.

Heterochromatin and rDNA sites distribution in the holocentric chromosomes of Cuscuta approximata Bab. (Convolvulaceae).

Science.gov (United States)

Guerra, Marcelo; García, Miguel A

2004-02-01

Cuscuta is a widely distributed genus of holoparasitic plants. Holocentric chromosomes have been reported only in species of one of its subgenera (Cuscuta subg. Cuscuta). In this work, a representative of this subgenus, Cuscuta approximata, was investigated looking for its mitotic and meiotic chromosome behaviour and the heterochromatin distribution. The mitotic chromosomes showed neither primary constriction nor Rabl orientation whereas the meiotic ones exhibited the typical quadripartite structure characteristic of holocentrics, supporting the assumption of holocentric chromosomes as a synapomorphy of Cuscuta subg. Cuscuta. Chromosomes and interphase nuclei displayed many heterochromatic blocks that stained deeply with hematoxylin, 4',6-diamidino-2-phenylindole (DAPI), or after C banding. The banded karyotype showed terminal or subterminal bands in all chromosomes and central bands in some of them. The single pair of 45S rDNA sites was observed at the end of the largest chromosome pair, close to a DAPI band and a 5S rDNA site. Two other 5S rDNA site pairs were found, both closely associated with DAPI bands. The noteworthy giant nuclei of glandular cells of petals and ovary wall exhibited large chromocentres typical of polytenic nuclei. The chromosomal location of heterochromatin and rDNA sites and the structure of the endoreplicated nuclei of C. approximata seemed to be similar to those known in monocentric nuclei, suggesting that centromeric organization has little or no effect on chromatin organization.

Epigenetic landscapes reveal transcription factors that regulate CD8+ T cell differentiation.

Science.gov (United States)

Yu, Bingfei; Zhang, Kai; Milner, J Justin; Toma, Clara; Chen, Runqiang; Scott-Browne, James P; Pereira, Renata M; Crotty, Shane; Chang, John T; Pipkin, Matthew E; Wang, Wei; Goldrath, Ananda W

2017-05-01

Dynamic changes in the expression of transcription factors (TFs) can influence the specification of distinct CD8 + T cell fates, but the observation of equivalent expression of TFs among differentially fated precursor cells suggests additional underlying mechanisms. Here we profiled the genome-wide histone modifications, open chromatin and gene expression of naive, terminal-effector, memory-precursor and memory CD8 + T cell populations induced during the in vivo response to bacterial infection. Integration of these data suggested that the expression and binding of TFs contributed to the establishment of subset-specific enhancers during differentiation. We developed a new bioinformatics method using the PageRank algorithm to reveal key TFs that influence the generation of effector and memory populations. The TFs YY1 and Nr3c1, both constitutively expressed during CD8 + T cell differentiation, regulated the formation of terminal-effector cell fates and memory-precursor cell fates, respectively. Our data define the epigenetic landscape of differentiation intermediates and facilitate the identification of TFs with previously unappreciated roles in CD8 + T cell differentiation.

Epigenetic inheritance in apomictic dandelions

NARCIS (Netherlands)

Preite, V.

2016-01-01

Epigenetic variation, such as changes in DNA methylations, regulatory small RNAs (sRNAs) and chromatin modifications can be induced by environmental stress. There is increasing information that such induced epigenetic modifications can be transmitted to offspring, potentially mediating adaptive

Epigenetic mechanisms of alcoholism and stress-related disorders.

Science.gov (United States)

Palmisano, Martina; Pandey, Subhash C

2017-05-01

Stress-related disorders, such as anxiety, early life stress, and posttraumatic stress disorder appear to be important factors in promoting alcoholism, as alcohol consumption can temporarily attenuate the negative affective symptoms of these disorders. Several molecules involved in signaling pathways may contribute to the neuroadaptation induced during alcohol dependence and stress disorders, and among these, brain-derived neurotrophic factor (BDNF), corticotropin releasing factor (CRF), neuropeptide Y (NPY) and opioid peptides (i.e., nociceptin and dynorphin) are involved in the interaction of stress and alcohol. In fact, alterations in the expression and function of these molecules have been associated with the pathophysiology of stress-related disorders and alcoholism. In recent years, various studies have focused on the epigenetic mechanisms that regulate chromatin architecture, thereby modifying gene expression. Interestingly, epigenetic modifications in specific brain regions have been shown to be associated with the neurobiology of psychiatric disorders, including alcoholism and stress. In particular, the enzymes responsible for chromatin remodeling (i.e., histone deacetylases and methyltransferases, DNA methyltransferases) have been identified as common molecular mechanisms for the interaction of stress and alcohol and have become promising therapeutic targets to treat or prevent alcoholism and associated emotional disorders. Published by Elsevier Inc.

Risk architecture of schizophrenia: the role of epigenetics.

Science.gov (United States)

Svrakic, Dragan M; Zorumski, Charles F; Svrakic, Nenad M; Zwir, Igor; Cloninger, Claude R

2013-03-01

To systematize existing data and review new findings on the cause of schizophrenia and outline an improved mixed model of schizophrenia risk. Multiple and variable genetic and environmental factors interact to influence the risk of schizophrenia. Both rare variants with large effect and common variants with small effect contribute to genetic risk of schizophrenia, with no indication for differential impact on its clinical features. Accumulating evidence supports a genetic architecture of schizophrenia with multiple scenarios, including additive polygenic, heterogeneity, and mixed polygenic-heterogeneity. The epigenetic mechanisms that mediate gene-environment (GxE) interactions provide a framework to incorporate environmental factors into models of schizophrenia risk. Environmental pathogens with small effect on risk have robust effects in the context of family history of schizophrenia. Hence, genetic risk for schizophrenia may be expressed in part as sensitivity to environmental factors. We propose an improved mixed model of schizophrenia risk in which abnormal epigenetic states with large effects are superimposed on a polygenic liability to schizophrenia. This scenario can account for GxE interactions and shared family environment, which in many cases are not explained by a single structural variant of large effect superimposed on polygenes (the traditional mixed model).

Environmental chemical exposures and human epigenetics

Science.gov (United States)

Hou, Lifang; Zhang, Xiao; Wang, Dong; Baccarelli, Andrea

2012-01-01

Every year more than 13 million deaths worldwide are due to environmental pollutants, and approximately 24% of diseases are caused by environmental exposures that might be averted through preventive measures. Rapidly growing evidence has linked environmental pollutants with epigenetic variations, including changes in DNA methylation, histone modifications and microRNAs. Environ mental chemicals and epigenetic changes All of these mechanisms are likely to play important roles in disease aetiology, and their modifications due to environmental pollutants might provide further understanding of disease aetiology, as well as biomarkers reflecting exposures to environmental pollutants and/or predicting the risk of future disease. We summarize the findings on epigenetic alterations related to environmental chemical exposures, and propose mechanisms of action by means of which the exposures may cause such epigenetic changes. We discuss opportunities, challenges and future directions for future epidemiology research in environmental epigenomics. Future investigations are needed to solve methodological and practical challenges, including uncertainties about stability over time of epigenomic changes induced by the environment, tissue specificity of epigenetic alterations, validation of laboratory methods, and adaptation of bioinformatic and biostatistical methods to high-throughput epigenomics. In addition, there are numerous reports of epigenetic modifications arising following exposure to environmental toxicants, but most have not been directly linked to disease endpoints. To complete our discussion, we also briefly summarize the diseases that have been linked to environmental chemicals-related epigenetic changes. PMID:22253299

Does epigenetic dysregulation of pancreatic islets contribute to impaired insulin secretion and type 2 diabetes?

Science.gov (United States)

Dayeh, Tasnim; Ling, Charlotte

2015-10-01

β cell dysfunction is central to the development and progression of type 2 diabetes (T2D). T2D develops when β cells are not able to compensate for the increasing demand for insulin caused by insulin resistance. Epigenetic modifications play an important role in establishing and maintaining β cell identity and function in physiological conditions. On the other hand, epigenetic dysregulation can cause a loss of β cell identity, which is characterized by reduced expression of genes that are important for β cell function, ectopic expression of genes that are not supposed to be expressed in β cells, and loss of genetic imprinting. Consequently, this may lead to β cell dysfunction and impaired insulin secretion. Risk factors that can cause epigenetic dysregulation include parental obesity, an adverse intrauterine environment, hyperglycemia, lipotoxicity, aging, physical inactivity, and mitochondrial dysfunction. These risk factors can affect the epigenome at different time points throughout the lifetime of an individual and even before an individual is conceived. The plasticity of the epigenome enables it to change in response to environmental factors such as diet and exercise, and also makes the epigenome a good target for epigenetic drugs that may be used to enhance insulin secretion and potentially treat diabetes.

Epigenetics in the Neoliberal "Regime of Truth": A Biopolitical Perspective on Knowledge Translation.

Science.gov (United States)

Dupras, Charles; Ravitsky, Vardit

2016-01-01

Recent findings in epigenetics have been attracting much attention from social scientists and bioethicists because they reveal the molecular mechanisms by which exposure to socioenvironmental factors, such as pollutants and social adversity, can influence the expression of genes throughout life. Most surprisingly, some epigenetic modifications may also be heritable via germ cells across generations. Epigenetics may be the missing molecular evidence of the importance of using preventive strategies at the policy level to reduce the incidence and prevalence of common diseases. But while this "policy translation" of epigenetics introduces new arguments in favor of public health strategies and policy-making, a more "clinical translation" of epigenetics is also emerging. It focuses on the biochemical mechanisms and epigenetic variants at the origin of disease, leading to novel biomedical means of assessing epigenetic susceptibility and reversing detrimental epigenetic variants. In this paper, we argue that the impetus to create new biomedical interventions to manipulate and reverse epigenetic variants is likely to garner more attention than effective social and public health interventions and therefore also to garner a greater share of limited public resources. This is likely to happen because of the current biopolitical context in which scientific findings are translated. This contemporary neoliberal "regime of truth," to use a term from Michel Foucault, greatly influences the ways in which knowledge is being interpreted and implemented. Building on sociologist Thomas Lemke's Foucauldian "analytics of biopolitics" and on literature from the field of science and technology studies, we present two sociological trends that may impede the policy translation of epigenetics: molecularization and biomedicalization. These trends, we argue, are likely to favor the clinical translation of epigenetics-in other words, the development of new clinical tools fostering what has been

The role of diet and exercise in the transgenerational epigenetic landscape of T2DM

DEFF Research Database (Denmark)

Barrès, Romain; Zierath, Juleen R

2016-01-01

Epigenetic changes are caused by biochemical regulators of gene expression that can be transferred across generations or through cell division. Epigenetic modifications can arise from a variety of environmental exposures including undernutrition, obesity, physical activity, stress and toxins. Tra...... of mechanisms by which lifestyle factors affect the epigenetic landscape in type 2 diabetes mellitus and obesity. Evidence from the past few years about the potential mechanisms by which diet and exercise affect the epigenome over several generations is discussed....... to environmental stressors. A detailed understanding of the epigenetic signatures of insulin resistance and the adaptive response to exercise might identify new therapeutic targets that can be further developed to improve insulin sensitivity and prevent obesity. This Review focuses on the current understanding...

Epigenetic Dysregulation in Laryngeal Squamous Cell Carcinoma

Directory of Open Access Journals (Sweden)

Thian-Sze Wong

2012-01-01

Full Text Available Laryngeal carcinoma is a common head and neck cancer with poor prognosis. Patients with laryngeal carcinoma usually present late leading to the reduced treatment efficacy and high rate of recurrence. Despite the advance in the use of molecular markers for monitoring human cancers in the past decades, there are still no reliable markers for use to screen laryngeal carcinoma and follow the patients after treatment. Epigenetics emerged as an important field in understanding the biology of the human malignancies. Epigenetic alterations refer to the dysregulation of gene, which do not involve the alterations of the DNA sequence. Major epigenetic changes including methylation imbalance, histone modification, and small RNA dysregulation could play a role in the development of human malignancies. Global epigenetic change is now regarded as a molecular signature of cancer. The characteristics and behavior of a cancer could be predicted based on the specific epigenetic pattern. We here provide a review on the understanding of epigenetic dysregulation in laryngeal carcinoma. Further knowledge on the initiation and progression of laryngeal carcinoma at epigenetic level could promote the translation of the knowledge to clinical use.

Evolutionary significance of epigenetic variation

NARCIS (Netherlands)

Richards, C.L.; Verhoeven, K.J.F.; Bossdorf, O.; Wendel, J.F.; Greilhuber, J.; Dolezel, J.; Leitch, I.J.

2012-01-01

Several chapters in this volume demonstrate how epigenetic work at the molecular level over the last few decades has revolutionized our understanding of genome function and developmental biology. However, epigenetic processes not only further our understanding of variation and regulation at the

Epigenetic marks: regulators of livestock phenotypes and conceivable sources of missing variation in livestock improvement programs

Directory of Open Access Journals (Sweden)

Eveline M Ibeagha-Awemu

2015-09-01

Full Text Available Improvement in animal productivity has been achieved over the years through careful breeding and selection programs. Today, variations in the genome are gaining increasing importance in livestock improvement strategies. Genomic information alone however explains only a part of the phenotypic variance in traits. It is likely that a portion of the unaccounted variance is embedded in the epigenome. The epigenome encompasses epigenetic marks such as DNA methylation, histone tail modifications, chromatin remodeling and other molecules that can transmit epigenetic information such as non-coding RNA species. Epigenetic factors respond to external or internal environmental cues such as nutrition, pathogens and climate, and have the ability to change gene expression leading to emergence of specific phenotypes. Accumulating evidence shows that epigenetic marks influence gene expression and phenotypic outcome in livestock species. This review examines available evidence of the influence of epigenetic marks on livestock (cattle, sheep, goat and pig traits and discusses the potential for consideration of epigenetic markers in livestock improvement programs. However, epigenetic research activities on farm animal species are currently limited partly due to lack of recognition, funding and a global network of researchers. Therefore, considerable less attention has been given to epigenetic research in livestock species in comparison to extensive work in humans and model organisms. Elucidating therefore the epigenetic determinants of animal diseases and complex traits may represent one of the principal challenges to use epigenetic markers for further improvement of animal productivity.

Conference scene: Select Biosciences Epigenetics Europe 2010.

Science.gov (United States)

Razvi, Enal S

2011-02-01

The field of epigenetics is now on a geometric rise, driven in a large part by the realization that modifiers of chromatin are key regulators of biological processes in vivo. The three major classes of epigenetic effectors are DNA methylation, histone post-translational modifications (such as acetylation, methylation or phosphorylation) and small noncoding RNAs (most notably microRNAs). In this article, I report from Select Biosciences Epigenetics Europe 2010 industry conference held on 14-15 September 2010 at The Burlington Hotel, Dublin, Ireland. This industry conference was extremely well attended with a global pool of delegates representing the academic research community, biotechnology companies and pharmaceutical companies, as well as the technology/tool developers. This conference represented the current state of the epigenetics community with cancer/oncology as a key driver. In fact, it has been estimated that approximately 45% of epigenetic researchers today identify cancer/oncology as their main area of focus vis-à-vis their epigenetic research efforts.

Using Epigenetic Therapy to Overcome Chemotherapy Resistance.

Science.gov (United States)

Strauss, Julius; Figg, William D

2016-01-01

It has been known for decades that as cancer progresses, tumors develop genetic alterations, making them highly prone to developing resistance to therapies. Classically, it has been thought that these acquired genetic changes are fixed. This has led to the paradigm of moving from one cancer therapy to the next while avoiding past therapies. However, emerging data on epigenetic changes during tumor progression and use of epigenetic therapies have shown that epigenetic modifications leading to chemotherapy resistance have the potential to be reversible with epigenetic therapy. In fact, promising clinical data exist that treatment with epigenetic agents can diminish chemotherapy resistance in a number of tumor types including chronic myelogenous leukemia, colorectal, ovarian, lung and breast cancer. The potential for epigenetic-modifying drugs to allow for treatment of resistant disease is exciting and clinical trials have just begun to evaluate this area. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Epigenetic Library Screen Identifies Abexinostat as Novel Regulator of Adipocytic and Osteoblastic Differentiation of Human Skeletal (Mesenchymal) Stem Cells

Science.gov (United States)

Ali, Dalia; Hamam, Rimi; Alfayez, Musaed; Kassem, Moustapha; Aldahmash, Abdullah

2016-01-01

The epigenetic mechanisms promoting lineage-specific commitment of human skeletal (mesenchymal or stromal) stem cells (hMSCs) into adipocytes or osteoblasts are still not fully understood. Herein, we performed an epigenetic library functional screen and identified several novel compounds, including abexinostat, which promoted adipocytic and osteoblastic differentiation of hMSCs. Using gene expression microarrays, chromatin immunoprecipitation for H3K9Ac combined with high-throughput DNA sequencing (ChIP-seq), and bioinformatics, we identified several key genes involved in regulating stem cell proliferation and differentiation that were targeted by abexinostat. Concordantly, ChIP-quantitative polymerase chain reaction revealed marked increase in H3K9Ac epigenetic mark on the promoter region of AdipoQ, FABP4, PPARγ, KLF15, CEBPA, SP7, and ALPL in abexinostat-treated hMSCs. Pharmacological inhibition of focal adhesion kinase (PF-573228) or insulin-like growth factor-1R/insulin receptor (NVP-AEW51) signaling exhibited significant inhibition of abexinostat-mediated adipocytic differentiation, whereas inhibition of WNT (XAV939) or transforming growth factor-β (SB505124) signaling abrogated abexinostat-mediated osteogenic differentiation of hMSCs. Our findings provide insight into the understanding of the relationship between the epigenetic effect of histone deacetylase inhibitors, transcription factors, and differentiation pathways governing adipocyte and osteoblast differentiation. Manipulating such pathways allows a novel use for epigenetic compounds in hMSC-based therapies and tissue engineering. Significance This unbiased epigenetic library functional screen identified several novel compounds, including abexinostat, that promoted adipocytic and osteoblastic differentiation of human skeletal (mesenchymal or stromal) stem cells (hMSCs). These data provide new insight into the understanding of the relationship between the epigenetic effect of histone deacetylase

Epigenetic Inheritance Across the Landscape

Directory of Open Access Journals (Sweden)

Amy Vaughn Whipple

2016-10-01

Full Text Available The study of epigenomic variation at the landscape-level in plants may add important insight to studies of adaptive variation. A major goal of landscape genomic studies is to identify genomic regions contributing to adaptive variation across the landscape. Heritable variation in epigenetic marks, resulting in transgenerational plasticity, can influence fitness-related traits. Epigenetic marks are influenced by the genome, the environment, and their interaction, and can be inherited independently of the genome. Thus, epigenomic variation likely influences the heritability of many adaptive traits, but the extent of this influence remains largely unknown. Here we summarize the relevance of epigenetic inheritance to ecological and evolutionary processes, and review the literature on landscape-level patterns of epigenetic variation. Landscape-level patterns of epigenomic variation in plants generally show greater levels of isolation by distance and isolation by environment then is found for the genome, but the causes of these patterns are not yet clear. Linkage between the environment and epigenomic variation has been clearly shown within a single generation, but demonstrating transgenerational inheritance requires more complex breeding and/or experimental designs. Transgenerational epigenetic variation may alter the interpretation of landscape genomic studies that rely upon phenotypic analyses, but should have less influence on landscape genomic approaches that rely upon outlier analyses or genome-environment associations. We suggest that multi-generation common garden experiments conducted across multiple environments will allow researchers to understand which parts of the epigenome are inherited, as well as to parse out the relative contribution of heritable epigenetic variation to the phenotype.

Epigenetic Inheritance across the Landscape.

Science.gov (United States)

Whipple, Amy V; Holeski, Liza M

2016-01-01

The study of epigenomic variation at the landscape-level in plants may add important insight to studies of adaptive variation. A major goal of landscape genomic studies is to identify genomic regions contributing to adaptive variation across the landscape. Heritable variation in epigenetic marks, resulting in transgenerational plasticity, can influence fitness-related traits. Epigenetic marks are influenced by the genome, the environment, and their interaction, and can be inherited independently of the genome. Thus, epigenomic variation likely influences the heritability of many adaptive traits, but the extent of this influence remains largely unknown. Here, we summarize the relevance of epigenetic inheritance to ecological and evolutionary processes, and review the literature on landscape-level patterns of epigenetic variation. Landscape-level patterns of epigenomic variation in plants generally show greater levels of isolation by distance and isolation by environment then is found for the genome, but the causes of these patterns are not yet clear. Linkage between the environment and epigenomic variation has been clearly shown within a single generation, but demonstrating transgenerational inheritance requires more complex breeding and/or experimental designs. Transgenerational epigenetic variation may alter the interpretation of landscape genomic studies that rely upon phenotypic analyses, but should have less influence on landscape genomic approaches that rely upon outlier analyses or genome-environment associations. We suggest that multi-generation common garden experiments conducted across multiple environments will allow researchers to understand which parts of the epigenome are inherited, as well as to parse out the relative contribution of heritable epigenetic variation to the phenotype.

[Epigenetics in allergic diseases and asthma].

Science.gov (United States)

Castro-Rodríguez, José A; Krause, Bernardo J; Uauy, Ricardo; Casanello, Paola

2016-01-01

Allergic diseases and asthma are the result of complex interactions between genetic predisposition and environmental factors. Asthma is one of the most prevalent chronic disease among children. In this article we review some environmental factors like: allergen exposition, tobacco, bacteria, microbial components, diet, obesity and stress, which influences during intrauterine and infancy life in the epigenetic regulation of asthma and allergic diseases. The review has been done in three models: in-vitro, animal and human. Copyright © 2016 Sociedad Chilena de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

Environmentally induced transgenerational epigenetic reprogramming of primordial germ cells and the subsequent germ line.

Directory of Open Access Journals (Sweden)

Michael K Skinner

Full Text Available A number of environmental factors (e.g. toxicants have been shown to promote the epigenetic transgenerational inheritance of disease and phenotypic variation. Transgenerational inheritance requires the germline transmission of altered epigenetic information between generations in the absence of direct environmental exposures. The primary periods for epigenetic programming of the germ line are those associated with primordial germ cell development and subsequent fetal germline development. The current study examined the actions of an agricultural fungicide vinclozolin on gestating female (F0 generation progeny in regards to the primordial germ cell (PGC epigenetic reprogramming of the F3 generation (i.e. great-grandchildren. The F3 generation germline transcriptome and epigenome (DNA methylation were altered transgenerationally. Interestingly, disruptions in DNA methylation patterns and altered transcriptomes were distinct between germ cells at the onset of gonadal sex determination at embryonic day 13 (E13 and after cord formation in the testis at embryonic day 16 (E16. A larger number of DNA methylation abnormalities (epimutations and transcriptional alterations were observed in the E13 germ cells than in the E16 germ cells. These observations indicate that altered transgenerational epigenetic reprogramming and function of the male germline is a component of vinclozolin induced epigenetic transgenerational inheritance of disease. Insights into the molecular control of germline transmitted epigenetic inheritance are provided.

The physics of epigenetics

Science.gov (United States)

Cortini, Ruggero; Barbi, Maria; Caré, Bertrand R.; Lavelle, Christophe; Lesne, Annick; Mozziconacci, Julien; Victor, Jean-Marc

2016-04-01

In higher organisms, all cells share the same genome, but every cell expresses only a limited and specific set of genes that defines the cell type. During cell division, not only the genome, but also the cell type is inherited by the daughter cells. This intriguing phenomenon is achieved by a variety of processes that have been collectively termed epigenetics: the stable and inheritable changes in gene expression patterns. This article reviews the extremely rich and exquisitely multiscale physical mechanisms that govern the biological processes behind the initiation, spreading, and inheritance of epigenetic states. These include not only the changes in the molecular properties associated with the chemical modifications of DNA and histone proteins, such as methylation and acetylation, but also less conventional changes, typically in the physics that governs the three-dimensional organization of the genome in cell nuclei. Strikingly, to achieve stability and heritability of epigenetic states, cells take advantage of many different physical principles, such as the universal behavior of polymers and copolymers, the general features of dynamical systems, and the electrostatic and mechanical properties related to chemical modifications of DNA and histones. By putting the complex biological literature in this new light, the emerging picture is that a limited set of general physical rules play a key role in initiating, shaping, and transmitting this crucial "epigenetic landscape." This new perspective not only allows one to rationalize the normal cellular functions, but also helps to understand the emergence of pathological states, in which the epigenetic landscape becomes dysfunctional.

Epigenetics and Cellular Metabolism

OpenAIRE

Wenyi Xu; Fengzhong Wang; Zhongsheng Yu; Fengjiao Xin

2016-01-01

Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc.) is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the proce...

Beyond repair foci: DNA double-strand break repair in euchromatic and heterochromatic compartments analyzed by transmission electron microscopy.

Directory of Open Access Journals (Sweden)

Yvonne Lorat

Full Text Available DNA double-strand breaks (DSBs generated by ionizing radiation pose a serious threat to the preservation of genetic and epigenetic information. The known importance of local chromatin configuration in DSB repair raises the question of whether breaks in different chromatin environments are recognized and repaired by the same repair machinery and with similar efficiency. An essential step in DSB processing by non-homologous end joining is the high-affinity binding of Ku70-Ku80 and DNA-PKcs to double-stranded DNA ends that holds the ends in physical proximity for subsequent repair.Using transmission electron microscopy to localize gold-labeled pKu70 and pDNA-PKcs within nuclear ultrastructure, we monitored the formation and repair of actual DSBs within euchromatin (electron-lucent and heterochromatin (electron-dense in cortical neurons of irradiated mouse brain.While DNA lesions in euchromatin (characterized by two pKu70-gold beads, reflecting the Ku70-Ku80 heterodimer are promptly sensed and rejoined, DNA packaging in heterochromatin appears to retard DSB processing, due to the time needed to unravel higher-order chromatin structures. Complex pKu70-clusters formed in heterochromatin (consisting of 4 or ≥ 6 gold beads may represent multiple breaks in close proximity caused by ionizing radiation of highly-compacted DNA. All pKu70-clusters disappeared within 72 hours post-irradiation, indicating efficient DSB rejoining. However, persistent 53BP1 clusters in heterochromatin (comprising ≥ 10 gold beads, occasionally co-localizing with γH2AX, but not pKu70 or pDNA-PKcs, may reflect incomplete or incorrect restoration of chromatin structure rather than persistently unrepaired DNA damage.Higher-order organization of chromatin determines the accessibility of DNA lesions to repair complexes, defining how readily DSBs are detected and processed. DNA lesions in heterochromatin appear to be more complex, with multiple breaks in spatial vicinity inducing

CROSSOVERS BETWEEN EPIGENESIS AND EPIGENETICS. A MULTICENTER APPROACH TO THE HISTORY OF EPIGENETICS (1901-1975).

Science.gov (United States)

Costa, Rossella; Frezza, Giulia

2014-01-01

The origin of epigenetics has been traditionally traced back to Conrad Hal Waddington's foundational work in 1940s. The aim of the present paper is to reveal a hidden history of epigenetics, by means of a multicenter approach. Our analysis shows that genetics and embryology in early XX century--far from being non-communicating vessels--shared similar questions, as epitomized by Thomas Hunt Morgan's works. Such questions were rooted in the theory of epigenesis and set the scene for the development of epigenetics. Since the 1950s, the contribution of key scientists (Mary Lyon and Eduardo Scarano), as well as the discussions at the international conference of Gif-sur-Yvette (1957) paved the way for three fundamental shifts of focus: 1. From the whole embryo to the gene; 2. From the gene to the complex extranuclear processes of development; 3. From cytoplasmic inheritance to the epigenetics mechanisms.

New insights in oncology: Epi-genetics and cancer stem cells

International Nuclear Information System (INIS)

Krutovskikh, V.; Partensky, C.

2011-01-01

Cancer is a multi-etiologic, multistage disease with a prevalent genetic component, which happens when a large number of genes, critical for cell growth, death, differentiation, migration, and metabolic plasticity are altered irreversibly, so as to either 'gain' (oncogenes) or 'lose' (tumour suppressors) their function. Recent discoveries have revealed the previously underestimated etiologic importance of multiple epigenetic, that is to say, reversible factors (histone modifications, DNA methylation, non-coding RNA) involved in the transcriptional and post-transcriptional regulation of proteins, indispensable for the control of cancerous phenotype. Stable alterations of epigenetic machinery ('epi-mutations') turn out to play a critical role at different steps of carcinogenesis. In addition, due to substantial recent progress in stem cell biology, the new concept of cancer stem cells has emerged. This, along with newly discovered epigenetic cancer mechanisms, gives rise to a hope to overcome radio- and chemo-resistance and to eradicate otherwise incurable neoplasms. (authors)

Developmental plasticity and epigenetic mechanisms underpinning metabolic and cardiovascular diseases.

Science.gov (United States)

Low, Felicia M; Gluckman, Peter D; Hanson, Mark A

2011-06-01

The importance of developmental factors in influencing the risk of later-life disease has a strong evidence base derived from multiple epidemiological, clinical and experimental studies in animals and humans. During early life, an organism is able to adjust its phenotypic development in response to environmental cues. Such developmentally plastic responses evolved as a fitness-maximizing strategy to cope with variable environments. There are now increasing data that these responses are, at least partially, underpinned by epigenetic mechanisms. A mismatch between the early and later-life environments may lead to inappropriate early life-course epigenomic changes that manifest in later life as increased vulnerability to disease. There is also growing evidence for the transgenerational transmission of epigenetic marks. This article reviews the evidence that susceptibility to metabolic and cardiovascular disease in humans is linked to changes in epigenetic marks induced by early-life environmental cues, and discusses the clinical, public health and therapeutic implications that arise.

Epigenetics and obesity: the devil is in the details.

Science.gov (United States)

Franks, Paul W; Ling, Charlotte

2010-12-21

Obesity is a complex disease with multiple well-defined risk factors. Nevertheless, susceptibility to obesity and its sequelae within obesogenic environments varies greatly from one person to the next, suggesting a role for gene × environment interactions in the etiology of the disorder. Epigenetic regulation of the human genome provides a putative mechanism by which specific environmental exposures convey risk for obesity and other human diseases and is one possible mechanism that underlies the gene × environment/treatment interactions observed in epidemiological studies and clinical trials. A study published in BMC Medicine this month by Wang et al. reports on an examination of DNA methylation in peripheral blood leukocytes of lean and obese adolescents, comparing methylation patterns between the two groups. The authors identified two genes that were differentially methylated, both of which have roles in immune function. Here we overview the findings from this study in the context of those emerging from other recent genetic and epigenetic studies, discuss the strengths and weaknesses of the study and speculate on the future of epigenetics in chronic disease research.

Epigenetics in Breast and Prostate Cancer

OpenAIRE

Wu, Yanyuan; Sarkissyan, Marianna; Vadgama, Jaydutt V.

2015-01-01

Most recent investigations into cancer etiology have identified a key role played by epigenetics. Specifically, aberrant DNA and histone modifications which silence tumor suppressor genes or promote oncogenes have been demonstrated in multiple cancer models. While the role of epigenetics in several solid tumor cancers such as colorectal cancer are well established, there is emerging evidence that epigenetics also plays a critical role in breast and prostate cancer. In breast cancer, DNA methy...

New insights into the epigenetics of inflammatory rheumatic diseases.

Science.gov (United States)

Ballestar, Esteban; Li, Tianlu

2017-10-01

Over the past decade, awareness of the importance of epigenetic alterations in the pathogenesis of rheumatic diseases has grown in parallel with a general recognition of the fundamental role of epigenetics in the regulation of gene expression. Large-scale efforts to generate genome-wide maps of epigenetic modifications in different cell types, as well as in physiological and pathological contexts, illustrate the increasing recognition of the relevance of epigenetics. To date, although several reports have demonstrated the occurrence of epigenetic alterations in a wide range of inflammatory rheumatic conditions, epigenomic information is rarely used in a clinical setting. By contrast, several epigenetic biomarkers and treatments are currently in use for personalized therapies in patients with cancer. This Review highlights advances from the past 5 years in the field of epigenetics and their application to inflammatory rheumatic diseases, delineating the future lines of development for a rational use of epigenetic information in clinical settings and in personalized medicine. These advances include the identification of epipolymorphisms associated with clinical outcomes, DNA methylation as a contributor to disease susceptibility in rheumatic conditions, the discovery of novel epigenetic mechanisms that modulate disease susceptibility and the development of new epigenetic therapies.

Epigenetics and cerebral organoids

DEFF Research Database (Denmark)

Forsberg, Sheena Louise; Ilieva, Mirolyuba; Maria Michel, Tanja

2018-01-01

also play a role. Some studies indicate a set of candidate genes with different DNA methylation profiles in ASD compared to healthy individuals. Thus epigenetic alterations could help bridging the gene-environment gap in deciphering the underlying neurobiology of autism. However, epigenome......-wide association studies (EWAS) have mainly included a very limited number of postmortem brain samples. Hence, cellular models mimicking brain development in vitro will be of great importance to study the critical epigenetic alterations and when they might happen. This review will give an overview of the state...... of the art concerning knowledge on epigenetic changes in autism and how new, cutting edge expertise based on three-dimensional (3D) stem cell technology models (brain organoids) can contribute in elucidating the multiple aspects of disease mechanisms....

Radiation-Induced Epigenetic Alterations after Low and High LET Irradiations

Energy Technology Data Exchange (ETDEWEB)

Aypar, Umut; Morgan, William F.; Baulch, Janet E.

2011-02-01

Epigenetics, including DNA methylation and microRNA (miRNA) expression, could be the missing link in understanding the delayed, non-targeted effects of radiation including radiationinduced genomic instability (RIGI). This study tests the hypothesis that irradiation induces epigenetic aberrations, which could eventually lead to RIGI, and that the epigenetic aberrations induced by low linear energy transfer (LET) irradiation are different than those induced by high LET irradiations. GM10115 cells were irradiated with low LET x-rays and high LET iron (Fe) ions and evaluated for DNA damage, cell survival and chromosomal instability. The cells were also evaluated for specific locus methylation of nuclear factor-kappa B (NFκB), tumor suppressor in lung cancer 1 (TSLC1) and cadherin 1 (CDH1) gene promoter regions, long interspersed nuclear element 1 (LINE-1) and Alu repeat element methylation, CpG and non-CpG global methylation and miRNA expression levels. Irradiated cells showed increased micronucleus induction and cell killing immediately following exposure, but were chromosomally stable at delayed times post-irradiation. At this same delayed time, alterations in repeat element and global DNA methylation and miRNA expression were observed. Analyses of DNA methylation predominantly showed hypomethylation, however hypermethylation was also observed. MiRNA shown to be altered in expression level after x-ray irradiation are involved in chromatin remodeling and DNA methylation. Different and higher incidence of epigenetic changes were observed after exposure to low LET x-rays than high LET Fe ions even though Fe ions elicited more chromosomal damage and cell killing. This study also shows that the irradiated cells acquire epigenetic changes even though they are chromosomally stable suggesting that epigenetic aberrations may arise in the cell without initiating RIGI.

Epigenetic regulation – contribution to herbicide resistance in weeds?

Czech Academy of Sciences Publication Activity Database

Markus, C.; Pečinka, Aleš; Karan, R.; Barney, J. N.; Merotto, A.

2018-01-01

Roč. 74, č. 2 (2018), s. 275-281 ISSN 1526-498X Institutional support: RVO:61389030 Keywords : DNA methylation * epigenetic s * gene expression * gene regulation * herbicide detoxification * plant stress response Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 3.253, year: 2016

Fumonisin FB1 treatment acts synergistically with methyl donor deficiency during rat pregnancy to produce alterations of H3- and H4-histone methylation patterns in fetuses.

Science.gov (United States)

Pellanda, Hélène; Forges, Thierry; Bressenot, Aude; Chango, Abalo; Bronowicki, Jean-Pierre; Guéant, Jean-Louis; Namour, Fares

2012-06-01

Prenatal folate and methyl donor malnutrition lead to epigenetic alterations that could enhance susceptibility to disease. Methyl-deficient diet (MDD) and fumonisin FB1 are risk factors for neural tube defects and cancers. Evidence indicates that FB1 impairs folate metabolism. Folate receptors and four heterochromatin markers were investigated in rat fetuses liver derived from dams exposed to MDD and/or FB1 administered at a dose twice higher than the provisional maximum tolerable daily intake (PMTDI = 2 μg/kg/day). Even though folate receptors transcription seemed up-regulated by methyl depletion regardless of FB1 treatment, combined MDD/FB1 exposure might reverse this up-regulation since folate receptors transcripts were lower in the MDD/FB1 versus MDD group. Methyl depletion decreased H4K20me3. Combined MDD/FB1 decreased H4K20me3 even more and increased H3K9me3. The elevated H3K9me3 can be viewed as a defense mechanism inciting the cell to resist heterochromatin disorganization. H3R2me2 and H4K16Ac varied according to this mechanism even though statistical significance was not consistent. Considering that humans are exposed to FB1 levels above the PMTDI, this study is relevant because it suggests that low doses of FB1 interact with MDD thus contributing to disrupt the epigenetic landscape. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Epigenetic Mechanisms Underlie Genome Development

Science.gov (United States)

Lamm, Ehud

2013-01-01

Technological and methodological advances, in particular next-generation sequencing and chromatin profiling, has led to a deluge of data on epigenetic mechanisms and processes. Epigenetic regulation in the brain is no exception. In this commentary, Ehud Lamm writes that extending existing frameworks for thinking about psychological development to…

Regulation of disease-responsive genes mediated by epigenetic factors: interaction of Arabidopsis-Pseudomonas.

Science.gov (United States)

De-La-Peña, Clelia; Rangel-Cano, Alicia; Alvarez-Venegas, Raúl

2012-05-01

Genes in eukaryotic organisms function within the context of chromatin, and the mechanisms that modulate the structure of chromatin are defined as epigenetic. In Arabidopsis, pathogen infection induces the expression of at least one histone deacetylase, suggesting that histone acetylation/deacetylation has an important role in the pathogenic response in plants. How/whether histone methylation affects gene response to pathogen infection is unknown. To gain a better understanding of the epigenetic mechanisms regulating the interaction between Pseudomonas syringae and Arabidopsis thaliana, we analysed three different Arabidopsis ash1-related (absent, small or homeotic discs 1) mutants. We found that the loss of function of ASHH2 and ASHR1 resulted in faster hypersensitive responses (HRs) to both mutant (hrpA) and pathogenic (DC3000) strains of P. syringae, whereas control (Col-0) and ashr3 mutants appeared to be more resistant to the infection after 2 days. Furthermore, we showed that, in the ashr3 background, the PR1 gene (PATHOGENESIS-RELATED GENE 1) displayed the highest expression levels on infection with DC3000, correlating with increased resistance against this pathogen. Our results show that, in both the ashr1 and ashh2 backgrounds, the histone H3 lysine 4 dimethylation (H3K4me2) levels decreased at the promoter region of PR1 on infection with the DC3000 strain, suggesting that an epigenetically regulated PR1 expression is involved in the plant defence. Our results suggest that histone methylation in response to pathogen infection may be a critical component in the signalling and defence processes occurring between plants and microbes. © 2011 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2011 BSPP AND BLACKWELL PUBLISHING LTD.

Is Neurofibromatosis Type 1-Noonan Syndrome a Phenotypic Result of Combined Genetic and Epigenetic Factors?

Science.gov (United States)

Yapijakis, Christos; Pachis, Nikos; Natsis, Stavros; Voumvourakis, Costas

2016-01-01

Neurofibromatosis 1-Noonan syndrome (NFNS) presents combined characteristics of both autosomal dominant disorders: NF1 and Noonan syndrome (NS). The genes causing NF1 and NS are located on different chromosomes, making it uncertain whether NFNS is a separate entity as previously suggested, or rather a clinical variation. We present a four-membered Greek family. The father was diagnosed with familial NF1 and the mother with generalized epilepsy, being under hydantoin treatment since the age of 18 years. Their two male children exhibited NFNS characteristics. The father and his sons shared R1947X mutation in the NF1 gene. The two children with NFNS phenotype presented with NF1 signs inherited from their father and fetal hydantoin syndrome-like phenotype due to exposure to that anticonvulsant during fetal development. The NFNS phenotype may be the result of both a genetic factor (mutation in the NF1 gene) and an epigenetic/environmental factor (e.g. hydantoin). Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Genetic, environmental, and epigenetic factors in the development of personality disturbance.

Science.gov (United States)

Depue, Richard A

2009-01-01

A dimensional model of personality disturbance is presented that is defined by extreme values on interacting subsets of seven major personality traits. Being at the extreme has marked effects on the threshold for eliciting those traits under stimulus conditions: that is, the extent to which the environment affects the neurobiological functioning underlying the traits. To explore the nature of development of extreme values on these traits, each trait is discussed in terms of three major issues: (a) the neurobiological variables associated with the trait, (b) individual variation in this neurobiology as a function of genetic polymorphisms, and (c) the effects of environmental adversity on these neurobiological variables through the action of epigenetic processes. It is noted that gene-environment interaction appears to be dependent on two main factors: (a) both genetic and environmental variables appear to have the most profound and enduring effects when they exert their effects during early postnatal periods, times when the forebrain is undergoing exuberant experience-expectant dendritic and axonal growth; and (b) environmental effects on neurobiology are strongly modified by individual differences in "traitlike" functioning of neurobiological variables. A model of the nature of the interaction between environmental and neurobiological variables in the development of personality disturbance is presented.

MicroRNAs, epigenetics and disease

DEFF Research Database (Denmark)

Silahtaroglu, Asli; Stenvang, Jan

2010-01-01

Epigenetics is defined as the heritable chances that affect gene expression without changing the DNA sequence. Epigenetic regulation of gene expression can be through different mechanisms such as DNA methylation, histone modifications and nucleosome positioning. MicroRNAs are short RNA molecules...... which do not code for a protein but have a role in post-transcriptional silencing of multiple target genes by binding to their 3' UTRs (untranslated regions). Both epigenetic mechanisms, such as DNA methylation and histone modifications, and the microRNAs are crucial for normal differentiation...... diseases. In the present chapter we will mainly focus on microRNAs and methylation and their implications in human disease, mainly in cancer....

Transgenerational epigenetic effects on animal behaviour.

Science.gov (United States)

Jensen, Per

2013-12-01

Over the last decade a shift in paradigm has occurred with respect to the interaction between environment and genes. It is now clear that animal genomes are regulated to a large extent as a result of input from environmental events and experiences, which cause short- and long-term modifications in epigenetic markings of DNA and histones. In this review, the evidence that such epigenetic modifications can affect the behaviour of animals is explored, and whether such acquired behaviour alterations can transfer across generation borders. First, the mechanisms by which experiences cause epigenetic modifications are examined. This includes, for example, methylation of cytosine in CpG positions and acetylation of histones, and studies showing that this can be modified by early experiences. Secondly, the evidence that specific modifications in the epigenome can be the cause of behaviour variation is reviewed. Thirdly, the extent to which this phenotypically active epigenetic variants can be inherited either through the germline or through reoccurring environmental conditions is examined. A particularly interesting observation is that epigenetic modifications are often linked to stress, and may possibly be mediated by steroid effects. Finally, the idea that transgenerationally stable epigenetic variants may serve as substrates for natural selection is explored, and it is speculated that they may even predispose for directed, non-random mutations. Copyright © 2013 Elsevier Ltd. All rights reserved.

Epigenetic Epidemiology of Complex Diseases Using Twins

DEFF Research Database (Denmark)

Tan, Qihua

2013-01-01

through multiple epigenetic mechanisms. This paper reviews the new developments in using twins to study disease-related epigenetic alterations, links them to lifetime environmental exposure with a focus on the discordant twin design and proposes novel data-analytical approaches with the aim of promoting...... a more efficient use of twins in epigenetic studies of complex human diseases....

Epigenetic inheritance, prions and evolution

Indian Academy of Sciences (India)

The field of epigenetics has grown explosively in the past two decades or so. As currently defined, epigenetics deals with heritable, metastable and usually reversible changes that do not involve alterations in DNA sequence, but alter the way that information encoded inDNAis utilized.The bulk of current research in ...

Epigenetics and a new look on metabolic syndrome

Czech Academy of Sciences Publication Activity Database

Kuneš, Jaroslav; Vaněčková, Ivana; Mikulášková, Barbora; Behuliak, Michal; Maletínská, L.; Zicha, Josef

2015-01-01

Roč. 64, č. 5 (2015), s. 611-620 ISSN 0862-8408 R&D Projects: GA MZd(CZ) NV15-25396A; GA ČR(CZ) GA15-08679S Institutional support: RVO:67985823 Keywords : metabolic syndrome * epigenetic s * transgenerational inheritance * gene-environmental interactions * obesity * hypertension Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 1.643, year: 2015

Epigenetics and Colorectal Cancer

Science.gov (United States)

Lao, Victoria Valinluck; Grady, William M.

2012-01-01

Colorectal cancer is a leading cause of cancer deaths in the world. It results from an accumulation of genetic and epigenetic changes in colon epithelial cells that transforms them into adenocarcinomas. There have been major advances in our understanding of cancer epigenetics over the last decade, particularly regarding aberrant DNA methylation. Assessment of the colon cancer epigenome has revealed that virtually all colorectal cancers have aberrantly methylated genes and the average colorectal cancer methylome has hundreds to thousands of abnormally methylated genes. As with gene mutations in the cancer genome, a subset of these methylated genes, called driver genes, is presumed to play a functional role in colorectal cancer. The assessment of methylated genes in colorectal cancers has also revealed a unique molecular subgroup of colorectal cancers called CpG Island Methylator Phenotype (CIMP) cancers; these tumors have a particularly high frequency of methylated genes. The advances in our understanding of aberrant methylation in colorectal cancer has led to epigenetic alterations being developed as clinical biomarkers for diagnostic, prognostic, and therapeutic applications. Progress in the assessment of epigenetic alterations in colorectal cancer and their clinical applications has shown that these alterations will be commonly used in the near future as molecular markers to direct the prevention and treatment of colorectal cancer. PMID:22009203

Molecular epigenetics in the management of ovarian cancer: Are we investigating a rational clinical promise?

Directory of Open Access Journals (Sweden)

Ha eNguyen

2014-04-01

Full Text Available Epigenetics is essentially a phenotypical change in gene expression without any alteration of the DNA sequence; the emergence of epigenetics in cancer research and mainstream oncology is fueling new hope. However, it is not yet known whether this knowledge will translate to improved clinical management of ovarian cancer. In this malignancy, women are still undergoing chemotherapy similar to what was approved in 1978, which to this day represents one of the biggest breakthroughs for treating ovarian cancer. While liquid tumors are benefitting from epigenetically-related therapies, solid tumors like ovarian cancer are not (yet?. Herein we will review the science of molecular epigenetics, especially DNA methylation, histone modifications and microRNA, but also include transcription factors since they, too, are important in ovarian cancer. Preclinical and clinical research on the role of epigenetic modifications is summarized as well. Sadly, ovarian cancer remains an idiopathic disease, for the most part, and there are many areas of patient management which could benefit from improved technology. This review will also highlight the evidence suggesting that epigenetics may have preclinical utility in pharmacology and clinical applications for prognosis and diagnosis. Lastly, drugs currently in clinical trials (i.e. histone deacetylase inhibitors are discussed along with the promise for epigenetics in the exploitation of chemoresistance. Whether epigenetics will ultimately be the answer to better management in ovarian cancer is currently unknown; what we have now is hope.

Recent Findings in Alzheimer Disease and Nutrition Focusing on Epigenetics12

Science.gov (United States)

2016-01-01

Alzheimer disease (AD) is a chronic neurodegenerative disease with no effective cure so far. The current review focuses on the epigenetic mechanisms of AD and how nutrition can influence the course of this disease through regulation of gene expression, according to the latest scientific findings. The search strategy was the use of scientific databases such as PubMed and Scopus in order to find relative research or review articles published in the years 2012–2015. By showing the latest data of various nutritional compounds, this study aims to stimulate the scientific community to recognize the value of nutrition in this subject. Epigenetics is becoming a very attractive subject for researchers because it can shed light on unknown aspects of complex diseases like AD. DNA methylation, histone modifications, and microRNAs are the principal epigenetic mechanisms involved in AD pathophysiology. Nutrition is an environmental factor that is related to AD through epigenetic pathways. Vitamin B-12, for instance, can alter the one-carbon metabolism and thus interfere in the DNA methylation process. The research results might seem ambiguous about the clinical role of nutrition, but there is strengthening evidence that proper nutrition can not only change epigenetic biomarker levels but also prevent the development of late-onset AD and attenuate cognition deficit. Nutrition might grow to become a preventive and even therapeutic alternative against AD, especially if combined with other antidementia interventions, brain exercise, physical training, etc. Epigenetic biomarkers can be a very helpful tool to help researchers find the exact nutrients needed to create specific remedies, and perhaps the same biomarkers can be used even in patient screening in the future. PMID:27633107

Epigenetics: A Fascinating Field with Profound Research, Clinical, & Public Health Implications

Science.gov (United States)

Stein, Richard A.; Davis, Devra Lee

2012-01-01

Epigenetics is emerging as one of the most dynamic and vibrant biomedical areas. Multiple lines of evidence confirm that inherited genetic changes alone cannot fully explain all phenotypic characteristics of live organisms, and additional factors, which are not encoded in the DNA sequence, are involved. The contribution of non-genetic factors is…

Understanding the connection between epigenetic DNA methylation and nucleosome positioning from computer simulations.

Directory of Open Access Journals (Sweden)

Guillem Portella

Full Text Available Cytosine methylation is one of the most important epigenetic marks that regulate the process of gene expression. Here, we have examined the effect of epigenetic DNA methylation on nucleosomal stability using molecular dynamics simulations and elastic deformation models. We found that methylation of CpG steps destabilizes nucleosomes, especially when these are placed in sites where the DNA minor groove faces the histone core. The larger stiffness of methylated CpG steps is a crucial factor behind the decrease in nucleosome stability. Methylation changes the positioning and phasing of the nucleosomal DNA, altering the accessibility of DNA to regulatory proteins, and accordingly gene functionality. Our theoretical calculations highlight a simple physical-based explanation on the foundations of epigenetic signaling.

Epigenetic mechanisms in the initiation of hematological malignancies

Directory of Open Access Journals (Sweden)

Ali Maleki

2011-10-01

Full Text Available Background: Cancer development is not restricted to the genetic changes, but also to epigenetic changes. Epigenetic processes are very important in the development of hematological malignancies. The main epigenetic alterations are aberrations in DNA methylation, post-translational modifications of histones, chromatin remodeling and microRNAs patterns, and these are associated with tumor genesis. All the various cellular pathways contributing to the neoplastic phenotype are affected by epigenetic genes in cancer. These pathways can be explored as biomarkers in clinical use for early detection of disease, malignancy classification and response to treatment with classical chemotherapy agents and epigenetic drugs. Materials and Method: A literature review was performed using PUBMED from 1985 to 2008. Cross referencing of discovered articles was also reviewed.Results: In chronic lymphocytic leukemia, regional hypermethylation of gene promoters leads to gene silencing. Many of these genes have tumor suppressor phenotypes. In myelodysplastic syndrome (MDS, CDKN2B (alias, P15, a cyclin-dependent kinase inhibitor that negatively regulates the cell cycle, has been shown to be hypermethylated in marrow stem (CD34+ cells in patients with MDS. At present both Vidaza and Decitabine (DNA methyltransferase inhibitors are approved for the treatment of MDS.Conclusion: Unlike mutations or deletions, DNA hypermethylation and histone deacetylation are potentially reversible by pharmacological inhibition, therefore those epigenetic changes have been recognized as promising novel therapeutic targets in hematopoietic malignances. In this review, we discussed molecular mechanisms of epigenetics, epigenetic changes in hematological malignancies and epigenetic based treatments

Cancer Development, Progression, and Therapy: An Epigenetic Overview

Science.gov (United States)

Sarkar, Sibaji; Horn, Garrick; Moulton, Kimberly; Oza, Anuja; Byler, Shannon; Kokolus, Shannon; Longacre, McKenna

2013-01-01

Carcinogenesis involves uncontrolled cell growth, which follows the activation of oncogenes and/or the deactivation of tumor suppression genes. Metastasis requires down-regulation of cell adhesion receptors necessary for tissue-specific, cell–cell attachment, as well as up-regulation of receptors that enhance cell motility. Epigenetic changes, including histone modifications, DNA methylation, and DNA hydroxymethylation, can modify these characteristics. Targets for these epigenetic changes include signaling pathways that regulate apoptosis and autophagy, as well as microRNA. We propose that predisposed normal cells convert to cancer progenitor cells that, after growing, undergo an epithelial-mesenchymal transition. This process, which is partially under epigenetic control, can create a metastatic form of both progenitor and full-fledged cancer cells, after which metastasis to a distant location may occur. Identification of epigenetic regulatory mechanisms has provided potential therapeutic avenues. In particular, epigenetic drugs appear to potentiate the action of traditional therapeutics, often by demethylating and re-expressing tumor suppressor genes to inhibit tumorigenesis. Epigenetic drugs may inhibit both the formation and growth of cancer progenitor cells, thus reducing the recurrence of cancer. Adopting epigenetic alteration as a new hallmark of cancer is a logical and necessary step that will further encourage the development of novel epigenetic biomarkers and therapeutics. PMID:24152442

Cancer Development, Progression, and Therapy: An Epigenetic Overview

Directory of Open Access Journals (Sweden)

McKenna Longacre

2013-10-01

Full Text Available Carcinogenesis involves uncontrolled cell growth, which follows the activation of oncogenes and/or the deactivation of tumor suppression genes. Metastasis requires down-regulation of cell adhesion receptors necessary for tissue-specific, cell–cell attachment, as well as up-regulation of receptors that enhance cell motility. Epigenetic changes, including histone modifications, DNA methylation, and DNA hydroxymethylation, can modify these characteristics. Targets for these epigenetic changes include signaling pathways that regulate apoptosis and autophagy, as well as microRNA. We propose that predisposed normal cells convert to cancer progenitor cells that, after growing, undergo an epithelial-mesenchymal transition. This process, which is partially under epigenetic control, can create a metastatic form of both progenitor and full-fledged cancer cells, after which metastasis to a distant location may occur. Identification of epigenetic regulatory mechanisms has provided potential therapeutic avenues. In particular, epigenetic drugs appear to potentiate the action of traditional therapeutics, often by demethylating and re-expressing tumor suppressor genes to inhibit tumorigenesis. Epigenetic drugs may inhibit both the formation and growth of cancer progenitor cells, thus reducing the recurrence of cancer. Adopting epigenetic alteration as a new hallmark of cancer is a logical and necessary step that will further encourage the development of novel epigenetic biomarkers and therapeutics.

Epigenetic modulators of thyroid cancer.

Science.gov (United States)

Rodríguez-Rodero, Sandra; Delgado-Álvarez, Elías; Díaz-Naya, Lucía; Martín Nieto, Alicia; Menéndez Torre, Edelmiro

2017-01-01

There are some well known factors involved in the etiology of thyroid cancer, including iodine deficiency, radiation exposure at early ages, or some genetic changes. However, epigenetic modulators that may contribute to development of these tumors and be helpful to for both their diagnosis and treatment have recently been discovered. The currently known changes in DNA methylation, histone modifications, and non-coding RNAs in each type of thyroid carcinoma are reviewed here. Copyright © 2016 SEEN. Publicado por Elsevier España, S.L.U. All rights reserved.

Daphnia as an Emerging Epigenetic Model Organism

Directory of Open Access Journals (Sweden)

Kami D. M. Harris

2012-01-01

Full Text Available Daphnia offer a variety of benefits for the study of epigenetics. Daphnia’s parthenogenetic life cycle allows the study of epigenetic effects in the absence of confounding genetic differences. Sex determination and sexual reproduction are epigenetically determined as are several other well-studied alternate phenotypes that arise in response to environmental stressors. Additionally, there is a large body of ecological literature available, recently complemented by the genome sequence of one species and transgenic technology. DNA methylation has been shown to be altered in response to toxicants and heavy metals, although investigation of other epigenetic mechanisms is only beginning. More thorough studies on DNA methylation as well as investigation of histone modifications and RNAi in sex determination and predator-induced defenses using this ecologically and evolutionarily important organism will contribute to our understanding of epigenetics.

Epigenetics in Prostate Cancer

OpenAIRE

Albany, Costantine; Alva, Ajjai S.; Aparicio, Ana M.; Singal, Rakesh; Yellapragada, Sarvari; Sonpavde, Guru; Hahn, Noah M.

2011-01-01

Prostate cancer (PC) is the most commonly diagnosed nonskin malignancy and the second most common cause of cancer death among men in the United States. Epigenetics is the study of heritable changes in gene expression caused by mechanisms other than changes in the underlying DNA sequences. Two common epigenetic mechanisms, DNA methylation and histone modification, have demonstrated critical roles in prostate cancer growth and metastasis. DNA hypermethylation of cytosine-guanine (CpG) rich sequ...

Structural aspects of the nucleolus and its associated heterochromatin in neurons

International Nuclear Information System (INIS)

Pessacq, T.P.; Vidal Rioja, L.A.

1975-01-01

The study of the structure of the nucleolus has received considerable attention in recent years. Most data have been provided by a number of electromicroscopical studies which to some extent are confirmatory of the previous opticomicroscopical findings of Estable and Sotelo (1951, 1952, 1955), Davis (1960), Altmann, Stoecker, and Thoenes (1963), O'Donell (1961), Lettre, and Siebs (1961), Bernhard, Bauer, Gropp, Haguenau and Oberling (1955) among others. In a recent work Melker (1970) points out the existence in neurons of a mammal of a particular arrangement of the nucleolus and its associated chromatin very similar to that already established in avian neurons (Pessacq 1969). The research reported here adds some new structural facts on nucleolar-heterochromatinic rapports which although recognizable in a great variety of cellular types appears with schematic clearness only in a limited number of highly specialized cells of some species. (auth.)

The developmental environment, epigenetic biomarkers and long-term health.

Science.gov (United States)

Godfrey, K M; Costello, P M; Lillycrop, K A

2015-10-01

Evidence from both human and animal studies has shown that the prenatal and early postnatal environments influence susceptibility to chronic disease in later life and suggests that epigenetic processes are an important mechanism by which the environment alters long-term disease risk. Epigenetic processes, including DNA methylation, histone modification and non-coding RNAs, play a central role in regulating gene expression. The epigenome is highly sensitive to environmental factors in early life, such as nutrition, stress, endocrine disruption and pollution, and changes in the epigenome can induce long-term changes in gene expression and phenotype. In this review we focus on how the early life nutritional environment can alter the epigenome leading to an altered susceptibility to disease in later life.

Beyond the Central Dogma: Bringing Epigenetics into the Classroom

Science.gov (United States)

Drits-Esser, Dina; Malone, Molly; Barber, Nicola C.; Stark, Louisa A.

2014-01-01

Epigenetics is the study of how external factors and internal cellular signals can lead to changes in the packaging and processing of DNA sequences, thereby altering the expression of genes and traits. Exploring the epigenome introduces students to environmental influences on our genes and the complexities of gene expression. A supplemental…

Induction of epigenetic variation in Arabidopsis by over-expression of DNA METHYLTRANSFERASE1 (MET1.

Directory of Open Access Journals (Sweden)

Samuel Brocklehurst

Full Text Available Epigenetic marks such as DNA methylation and histone modification can vary among plant accessions creating epi-alleles with different levels of expression competence. Mutations in epigenetic pathway functions are powerful tools to induce epigenetic variation. As an alternative approach, we investigated the potential of over-expressing an epigenetic function, using DNA METHYLTRANSFERASE1 (MET1 for proof-of-concept. In Arabidopsis thaliana, MET1 controls maintenance of cytosine methylation at symmetrical CG positions. At some loci, which contain dense DNA methylation in CG- and non-CG context, loss of MET1 causes joint loss of all cytosines methylation marks. We find that over-expression of both catalytically active and inactive versions of MET1 stochastically generates new epi-alleles at loci encoding transposable elements, non-coding RNAs and proteins, which results for most loci in an increase in expression. Individual transformants share some common phenotypes and genes with altered gene expression. Altered expression states can be transmitted to the next generation, which does not require the continuous presence of the MET1 transgene. Long-term stability and epigenetic features differ for individual loci. Our data show that over-expression of MET1, and potentially of other genes encoding epigenetic factors, offers an alternative strategy to identify epigenetic target genes and to create novel epi-alleles.

Epigenetic Regulation in Particulate Matter-Mediated Cardiopulmonary Toxicities: A Systems Biology Perspective.

Science.gov (United States)

Wang, Ting; Garcia, Joe Gn; Zhang, Wei

2012-12-01

Particulate matter (PM) air pollution exerts significant adverse health effects in global populations, particularly in developing countries with extensive air pollution. Understanding of the mechanisms of PM-induced health effects including the risk for cardiovascular diseases remains limited. In addition to the direct cellular physiological responses such as mitochondrial dysfunction and oxidative stress, PM mediates remarkable dysregulation of gene expression, especially in cardiovascular tissues. The PM-mediated gene dysregulation is likely to be a complex mechanism affected by various genetic and non-genetic factors. Notably, PM is known to alter epigenetic markers (e.g., DNA methylation and histone modifications), which may contribute to air pollution-mediated health consequences including the risk for cardiovascular diseases. Notably, epigenetic changes induced by ambient PM exposure have emerged to play a critical role in gene regulation. Though the underlying mechanism(s) are not completely clear, the available evidence suggests that the modulated activities of DNA methyltransferase (DNMT), histone acetylase (HAT) and histone deacetylase (HDAC) may contribute to the epigenetic changes induced by PM or PM-related chemicals. By employing genome-wide epigenomic and systems biology approaches, PM toxicogenomics could conceivably progress greatly with the potential identification of individual epigenetic loci associated with dysregulated gene expression after PM exposure, as well the interactions between epigenetic pathways and PM. Furthermore, novel therapeutic targets based on epigenetic markers could be identified through future epigenomic studies on PM-mediated cardiopulmonary toxicities. These considerations collectively inform the future population health applications of genomics in developing countries while benefiting global personalized medicine at the same time.

Circadian clocks, epigenetics, and cancer

KAUST Repository

Masri, Selma; Kinouchi, Kenichiro; Sassone-Corsi, Paolo

2015-01-01

The interplay between circadian rhythm and cancer has been suggested for more than a decade based on the observations that shift work and cancer incidence are linked. Accumulating evidence implicates the circadian clock in cancer survival and proliferation pathways. At the molecular level, multiple control mechanisms have been proposed to link circadian transcription and cell-cycle control to tumorigenesis.The circadian gating of the cell cycle and subsequent control of cell proliferation is an area of active investigation. Moreover, the circadian clock is a transcriptional system that is intricately regulated at the epigenetic level. Interestingly, the epigenetic landscape at the level of histone modifications, DNA methylation, and small regulatory RNAs are differentially controlled in cancer cells. This concept raises the possibility that epigenetic control is a common thread linking the clock with cancer, though little scientific evidence is known to date.This review focuses on the link between circadian clock and cancer, and speculates on the possible connections at the epigenetic level that could further link the circadian clock to tumor initiation or progression.

Epigenetics in cancer stem cells.

Science.gov (United States)

Toh, Tan Boon; Lim, Jhin Jieh; Chow, Edward Kai-Hua

2017-02-01

Compelling evidence have demonstrated that bulk tumors can arise from a unique subset of cells commonly termed "cancer stem cells" that has been proposed to be a strong driving force of tumorigenesis and a key mechanism of therapeutic resistance. Recent advances in epigenomics have illuminated key mechanisms by which epigenetic regulation contribute to cancer progression. In this review, we present a discussion of how deregulation of various epigenetic pathways can contribute to cancer initiation and tumorigenesis, particularly with respect to maintenance and survival of cancer stem cells. This information, together with several promising clinical and preclinical trials of epigenetic modulating drugs, offer new possibilities for targeting cancer stem cells as well as improving cancer therapy overall.

Epigenetic Impact on EBV Associated B-Cell Lymphomagenesis

Directory of Open Access Journals (Sweden)

Shatadru Ghosh Roy

2016-11-01

Full Text Available Epigenetic modifications leading to either transcriptional repression or activation, play an indispensable role in the development of human cancers. Epidemiological study revealed that approximately 20% of all human cancers are associated with tumor viruses. Epstein-Barr virus (EBV, the first human tumor virus, demonstrates frequent epigenetic alterations on both viral and host genomes in associated cancers—both of epithelial and lymphoid origin. The cell type-dependent different EBV latent gene expression patterns appear to be determined by the cellular epigenetic machinery and similarly viral oncoproteins recruit epigenetic regulators in order to deregulate the cellular gene expression profile resulting in several human cancers. This review elucidates the epigenetic consequences of EBV–host interactions during development of multiple EBV-induced B-cell lymphomas, which may lead to the discovery of novel therapeutic interventions against EBV-associated B-cell lymphomas by alteration of reversible patho-epigenetic markings.

Epigenetic reprogramming in the porcine germ line

DEFF Research Database (Denmark)

Matzen, Sara Maj Hyldig; Croxall, Nicola; Contreras, David A.

2011-01-01

BACKGROUND: Epigenetic reprogramming is critical for genome regulation during germ line development. Genome-wide demethylation in mouse primordial germ cells (PGC) is a unique reprogramming event essential for erasing epigenetic memory and preventing the transmission of epimutations to the next...... an increased proportion of cells in G2. CONCLUSIONS: Our study demonstrates that epigenetic reprogramming occurs in pig migratory and gonadal PGC, and establishes the window of time for the occurrence of these events. Reprogramming of histone H3K9me2 and H3K27me3 detected between E15-E21 precedes the dynamic...... DNA demethylation at imprinted loci and DNA repeats between E22-E42. Our findings demonstrate that major epigenetic reprogramming in the pig germ line follows the overall dynamics shown in mice, suggesting that epigenetic reprogramming of germ cells is conserved in mammals. A better understanding...

Epigenetic game theory: How to compute the epigenetic control of maternal-to-zygotic transition

Science.gov (United States)

Wang, Qian; Gosik, Kirk; Xing, Sujuan; Jiang, Libo; Sun, Lidan; Chinchilli, Vernon M.; Wu, Rongling

2017-03-01

Epigenetic reprogramming is thought to play a critical role in maintaining the normal development of embryos. How the methylation state of paternal and maternal genomes regulates embryogenesis depends on the interaction and coordination of the gametes of two sexes. While there is abundant research in exploring the epigenetic interactions of sperms and oocytes, a knowledge gap exists in the mechanistic quantitation of these interactions and their impact on embryo development. This review aims at formulating a modeling framework to address this gap through the integration and synthesis of evolutionary game theory and the latest discoveries of the epigenetic control of embryo development by next-generation sequencing. This framework, named epigenetic game theory or epiGame, views embryogenesis as an ecological system in which two highly distinct and specialized gametes coordinate through either cooperation or competition, or both, to maximize the fitness of embryos under Darwinian selection. By implementing a system of ordinary differential equations, epiGame quantifies the pattern and relative magnitude of the methylation effects on embryogenesis by the mechanisms of cooperation and competition. epiGame may gain new insight into reproductive biology and can be potentially applied to design personalized medicines for genetic disorder intervention.

Epigenetics in prostate cancer.

Science.gov (United States)

Albany, Costantine; Alva, Ajjai S; Aparicio, Ana M; Singal, Rakesh; Yellapragada, Sarvari; Sonpavde, Guru; Hahn, Noah M

2011-01-01

Prostate cancer (PC) is the most commonly diagnosed nonskin malignancy and the second most common cause of cancer death among men in the United States. Epigenetics is the study of heritable changes in gene expression caused by mechanisms other than changes in the underlying DNA sequences. Two common epigenetic mechanisms, DNA methylation and histone modification, have demonstrated critical roles in prostate cancer growth and metastasis. DNA hypermethylation of cytosine-guanine (CpG) rich sequence islands within gene promoter regions is widespread during neoplastic transformation of prostate cells, suggesting that treatment-induced restoration of a "normal" epigenome could be clinically beneficial. Histone modification leads to altered tumor gene function by changing chromosome structure and the level of gene transcription. The reversibility of epigenetic aberrations and restoration of tumor suppression gene function have made them attractive targets for prostate cancer treatment with modulators that demethylate DNA and inhibit histone deacetylases.

Role of chromatin structure in telomere maintenance

Czech Academy of Sciences Publication Activity Database

Kunická, Zuzana; Muselíková Polanská, Eva; Dvořáčková, Martina; Štros, Michal; Fajkus, Jiří

2008-01-01

Roč. 28, 5C (2008), s. 193 ISSN 0250-7005. [Eighth International Conference of Anticancer Research. 17.10.2008-22.10.2008, Kos] R&D Projects: GA ČR(CZ) GA204/08/1530 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : telomeres * epigenetics * heterochromatin Subject RIV: BO - Biophysics

Epigenetic regulation of enteric neurotransmission by gut bacteria.

Directory of Open Access Journals (Sweden)

Tor eSavidge

2016-01-01

Full Text Available The Human Microbiome Project defined microbial community interactions with the human host, and provided important molecular insight into how epigenetic factors can influence intestinal ecosystems. Given physiological context, changes in gut microbial community structure are increasingly found to associate with alterations in enteric neurotransmission and disease. At present, it is not known whether shifts in microbial community dynamics represent cause or consequence of disease pathogenesis. The discovery of bacterial-derived neurotransmitters suggests further studies are needed to establish their role in enteric neuropathy. This mini-review highlights recent advances in bacterial communications to the autonomic nervous system and discusses emerging epigenetic data showing that diet, probiotic and antibiotic use may regulate enteric neurotransmission through modulation of microbial communities. Because of its limited scope, a particular emphasis is placed on bacterial regulation of enteric nervous system function in the intestine.

Epigenetics: a link between addiction and social environment.

Science.gov (United States)

Ajonijebu, Duyilemi C; Abboussi, Oualid; Russell, Vivienne A; Mabandla, Musa V; Daniels, William M U

2017-08-01

The detrimental effects of drug abuse are apparently not limited to individuals but may also impact the vulnerability of their progenies to develop addictive behaviours. Epigenetic signatures, early life experience and environmental factors, converge to influence gene expression patterns in addiction phenotypes and consequently may serve as mediators of behavioural trait transmission between generations. The majority of studies investigating the role of epigenetics in addiction do not consider the influence of social interactions. This shortcoming in current experimental approaches necessitates developing social models that reflect the addictive behaviour in a free-living social environment. Furthermore, this review also reports on the advancement of interventions for drug addiction and takes into account the emerging roles of histone deacetylase (HDAC) inhibitors in the etiology of drug addiction and that HDAC may be a potential therapeutic target at nucleosomal level to improve treatment outcomes.

Epigenetic impact of curcumin on stroke prevention

OpenAIRE

Kalani, Anuradha; Kamat, Pradip K; Kalani, Komal; Tyagi, Neetu

2014-01-01

The epigenetic impact of curcumin in stroke and neurodegenerative disorders is curiosity-arousing. It is derived from Curcuma longa (spice), possesses anti-oxidative, anti-inflammatory, anti-lipidemic, neuro-protective and recently shown to exhibit epigenetic modulatory properties. Epigenetic studies include DNA methylation, histone modifications and RNA-based mechanisms which regulate gene expression without altering nucleotide sequences. Curcumin has been shown to affect cancer by altering ...

The evolutionary implications of epigenetic inheritance.

Science.gov (United States)

Jablonka, Eva

2017-10-06

The Modern Evolutionary Synthesis (MS) forged in the mid-twentieth century was built on a notion of heredity that excluded soft inheritance, the inheritance of the effects of developmental modifications. However, the discovery of molecular mechanisms that generate random and developmentally induced epigenetic variations is leading to a broadening of the notion of biological heredity that has consequences for ideas about evolution. After presenting some old challenges to the MS that were raised, among others, by Karl Popper, I discuss recent research on epigenetic inheritance, which provides experimental and theoretical support for these challenges. There is now good evidence that epigenetic inheritance is ubiquitous and is involved in adaptive evolution and macroevolution. I argue that the many evolutionary consequences of epigenetic inheritance open up new research areas and require the extension of the evolutionary synthesis beyond the current neo-Darwinian model.

Environmentally induced epigenetic toxicity: potential public health concerns.

Science.gov (United States)

Marczylo, Emma L; Jacobs, Miriam N; Gant, Timothy W

2016-09-01

Throughout our lives, epigenetic processes shape our development and enable us to adapt to a constantly changing environment. Identifying and understanding environmentally induced epigenetic change(s) that may lead to adverse outcomes is vital for protecting public health. This review, therefore, examines the present understanding of epigenetic mechanisms involved in the mammalian life cycle, evaluates the current evidence for environmentally induced epigenetic toxicity in human cohorts and rodent models and highlights the research considerations and implications of this emerging knowledge for public health and regulatory toxicology. Many hundreds of studies have investigated such toxicity, yet relatively few have demonstrated a mechanistic association among specific environmental exposures, epigenetic changes and adverse health outcomes in human epidemiological cohorts and/or rodent models. While this small body of evidence is largely composed of exploratory in vivo high-dose range studies, it does set a precedent for the existence of environmentally induced epigenetic toxicity. Consequently, there is worldwide recognition of this phenomenon, and discussion on how to both guide further scientific research towards a greater mechanistic understanding of environmentally induced epigenetic toxicity in humans, and translate relevant research outcomes into appropriate regulatory policies for effective public health protection.

Epigenetics and a new look on metabolic syndrome

Czech Academy of Sciences Publication Activity Database

Kuneš, Jaroslav; Vaněčková, I.; Mikulášková, Barbora; Behuliak, M.; Maletínská, Lenka; Zicha, J.

2015-01-01

Roč. 64, č. 5 (2015), s. 611-620 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA15-08679S Institutional support: RVO:61388963 Keywords : metabolic syndrome * epigenetic s * transgenerational inheritance * gene-environmental interactions * obesity * hypertension Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 1.643, year: 2015 http://www.biomed.cas.cz/physiolres/pdf/64/64_611.pdf

Protocol for assessing maternal, environmental and epigenetic risk factors for dental caries in children.

Science.gov (United States)

Fernando, Surani; Speicher, David J; Bakr, Mahmoud M; Benton, Miles C; Lea, Rodney A; Scuffham, Paul A; Mihala, Gabor; Johnson, Newell W

2015-12-29

Expenditure on dental and oral health services in Australia is $3.4 billion AUD annually. This is the sixth highest health cost and accounts for 7 % of total national health expenditure. Approximately 49 % of Australian children aged 6 years have caries experience in their deciduous teeth and this is rising. The aetiology of dental caries involves a complex interplay of individual, behavioural, social, economic, political and environmental conditions, and there is increasing interest in genetic predisposition and epigenetic modification. The Oral Health Sub-study; a cross sectional study of a birth cohort began in November 2012 by examining mothers and their children who were six years old by the time of initiation of the study, which is ongoing. Data from detailed questionnaires of families from birth onwards and data on mothers' knowledge, attitudes and practices towards oral health collected at the time of clinical examination are used. Subjects' height, weight and mid-waist circumference are taken and Body Mass Index (BMI) computed, using an electronic Bio-Impedance balance. Dental caries experience is scored using the International Caries Detection and Assessment System (ICDAS). Saliva is collected for physiological measures. Salivary Deoxyribose Nucleic Acid (DNA) is extracted for genetic studies including epigenetics using the SeqCap Epi Enrichment Kit. Targets of interest are being confirmed by pyrosequencing to identify potential epigenetic markers of caries risk. This study will examine a wide range of potential determinants for childhood dental caries and evaluate inter-relationships amongst them. The findings will provide an evidence base to plan and implement improved preventive strategies.

Widespread epigenetic abnormalities suggest a broad DNA methylation erasure defect in abnormal human sperm.

Directory of Open Access Journals (Sweden)

Sahar Houshdaran

2007-12-01

Full Text Available Male-factor infertility is a common condition, and etiology is unknown for a high proportion of cases. Abnormal epigenetic programming of the germline is proposed as a possible mechanism compromising spermatogenesis of some men currently diagnosed with idiopathic infertility. During germ cell maturation and gametogenesis, cells of the germ line undergo extensive epigenetic reprogramming. This process involves widespread erasure of somatic-like patterns of DNA methylation followed by establishment of sex-specific patterns by de novo DNA methylation. Incomplete reprogramming of the male germ line could, in theory, result in both altered sperm DNA methylation and compromised spermatogenesis.We determined concentration, motility and morphology of sperm in semen samples collected by male members of couples attending an infertility clinic. Using MethyLight and Illumina assays we measured methylation of DNA isolated from purified sperm from the same samples. Methylation at numerous sequences was elevated in DNA from poor quality sperm.This is the first report of a broad epigenetic defect associated with abnormal semen parameters. Our results suggest that the underlying mechanism for these epigenetic changes may be improper erasure of DNA methylation during epigenetic reprogramming of the male germ line.

Transgenerational epigenetics and environmental justice.

Science.gov (United States)

Rothstein, Mark A; Harrell, Heather L; Marchant, Gary E

2017-07-01

Human transmission to offspring and future generations of acquired epigenetic modifications has not been definitively established, although there are several environmental exposures with suggestive evidence. This article uses three examples of hazardous substances with greater exposures in vulnerable populations: pesticides, lead, and diesel exhaust. It then considers whether, if there were scientific evidence of transgenerational epigenetic inheritance, there would be greater attention given to concerns about environmental justice in environmental laws, regulations, and policies at all levels of government. To provide a broader perspective on environmental justice the article discusses two of the most commonly cited approaches to environmental justice. John Rawls's theory of justice as fairness, a form of egalitarianism, is frequently invoked for the principle that differential treatment of individuals is justified only if actions are designed to benefit those with the greatest need. Another theory, the capabilities approach of Amartya Sen and Martha Nussbaum, focuses on whether essential capabilities of society, such as life and health, are made available to all individuals. In applying principles of environmental justice the article considers whether there is a heightened societal obligation to protect the most vulnerable individuals from hazardous exposures that could adversely affect their offspring through epigenetic mechanisms. It concludes that unless there were compelling evidence of transgenerational epigenetic harms, it is unlikely that there would be a significant impetus to adopt new policies to prevent epigenetic harms by invoking principles of environmental justice.

Prostate cancer epigenetics and its clinical implications.

Science.gov (United States)

Yegnasubramanian, Srinivasan

2016-01-01

Normal cells have a level of epigenetic programming that is superimposed on the genetic code to establish and maintain their cell identity and phenotypes. This epigenetic programming can be thought as the architecture, a sort of cityscape, that is built upon the underlying genetic landscape. The epigenetic programming is encoded by a complex set of chemical marks on DNA, on histone proteins in nucleosomes, and by numerous context-specific DNA, RNA, protein interactions that all regulate the structure, organization, and function of the genome in a given cell. It is becoming increasingly evident that abnormalities in both the genetic landscape and epigenetic cityscape can cooperate to drive carcinogenesis and disease progression. Large-scale cancer genome sequencing studies have revealed that mutations in genes encoding the enzymatic machinery for shaping the epigenetic cityscape are among the most common mutations observed in human cancers, including prostate cancer. Interestingly, although the constellation of genetic mutations in a given cancer can be quite heterogeneous from person to person, there are numerous epigenetic alterations that appear to be highly recurrent, and nearly universal in a given cancer type, including in prostate cancer. The highly recurrent nature of these alterations can be exploited for development of biomarkers for cancer detection and risk stratification and as targets for therapeutic intervention. Here, we explore the basic principles of epigenetic processes in normal cells and prostate cancer cells and discuss the potential clinical implications with regards to prostate cancer biomarker development and therapy.

Prostate cancer epigenetics and its clinical implications

Directory of Open Access Journals (Sweden)

Srinivasan Yegnasubramanian

2016-01-01

Full Text Available Normal cells have a level of epigenetic programming that is superimposed on the genetic code to establish and maintain their cell identity and phenotypes. This epigenetic programming can be thought as the architecture, a sort of cityscape, that is built upon the underlying genetic landscape. The epigenetic programming is encoded by a complex set of chemical marks on DNA, on histone proteins in nucleosomes, and by numerous context-specific DNA, RNA, protein interactions that all regulate the structure, organization, and function of the genome in a given cell. It is becoming increasingly evident that abnormalities in both the genetic landscape and epigenetic cityscape can cooperate to drive carcinogenesis and disease progression. Large-scale cancer genome sequencing studies have revealed that mutations in genes encoding the enzymatic machinery for shaping the epigenetic cityscape are among the most common mutations observed in human cancers, including prostate cancer. Interestingly, although the constellation of genetic mutations in a given cancer can be quite heterogeneous from person to person, there are numerous epigenetic alterations that appear to be highly recurrent, and nearly universal in a given cancer type, including in prostate cancer. The highly recurrent nature of these alterations can be exploited for development of biomarkers for cancer detection and risk stratification and as targets for therapeutic intervention. Here, we explore the basic principles of epigenetic processes in normal cells and prostate cancer cells and discuss the potential clinical implications with regards to prostate cancer biomarker development and therapy.

Epigenetic Regulation of Inflammatory Cytokines and Associated Genes in Human Malignancies

Directory of Open Access Journals (Sweden)

Rehana Yasmin

2015-01-01

Full Text Available Inflammation is a multifaceted defense response of immune system against infection. Chronic inflammation has been implicated as an imminent threat for major human malignancies and is directly linked to various steps involved in tumorigenesis. Inflammatory cytokines, interleukins, interferons, transforming growth factors, chemokines, and adhesion molecules have been associated with chronic inflammation. Numerous cytokines are reported to be aberrantly regulated by different epigenetic mechanisms like DNA methylation and histone modifications in tumor tissues, contributing to pathogenesis of tumor in multiple ways. Some of these cytokines also work as epigenetic regulators of other crucial genes in tumor biology, either directly or indirectly. Such regulations are reported in lung, breast, cervical, gastric, colorectal, pancreatic, prostate, and head and neck cancers. Epigenetics of inflammatory mediators in cancer is currently subject of extensive research. These investigations may help in understanding cancer biology and to develop effective therapeutic strategies. The purpose of this paper is to have a brief view of the aberrant regulation of inflammatory cytokines in human malignancies.

Hierarchical Oct4 Binding in Concert with Primed Epigenetic Rearrangements during Somatic Cell Reprogramming

Directory of Open Access Journals (Sweden)

Jun Chen

2016-02-01

Full Text Available The core pluripotency factor Oct4 plays key roles in somatic cell reprogramming through transcriptional control. Here, we profile Oct4 occupancy, epigenetic changes, and gene expression in reprogramming. We find that Oct4 binds in a hierarchical manner to target sites with primed epigenetic modifications. Oct4 binding is temporally continuous and seldom switches between bound and unbound. Oct4 occupancy in most of promoters is maintained throughout the entire reprogramming process. In contrast, somatic cell-specific enhancers are silenced in the early and intermediate stages, whereas stem cell-specific enhancers are activated in the late stage in parallel with cell fate transition. Both epigenetic remodeling and Oct4 binding contribute to the hyperdynamic enhancer signature transitions. The hierarchical Oct4 bindings are associated with distinct functional themes at different stages. Collectively, our results provide a comprehensive molecular roadmap of Oct4 binding in concert with epigenetic rearrangements and rich resources for future reprogramming studies.

Epigenetics and obesity: the devil is in the details

Directory of Open Access Journals (Sweden)

Franks Paul W

2010-12-01

Full Text Available Abstract Obesity is a complex disease with multiple well-defined risk factors. Nevertheless, susceptibility to obesity and its sequelae within obesogenic environments varies greatly from one person to the next, suggesting a role for gene × environment interactions in the etiology of the disorder. Epigenetic regulation of the human genome provides a putative mechanism by which specific environmental exposures convey risk for obesity and other human diseases and is one possible mechanism that underlies the gene × environment/treatment interactions observed in epidemiological studies and clinical trials. A study published in BMC Medicine this month by Wang et al. reports on an examination of DNA methylation in peripheral blood leukocytes of lean and obese adolescents, comparing methylation patterns between the two groups. The authors identified two genes that were differentially methylated, both of which have roles in immune function. Here we overview the findings from this study in the context of those emerging from other recent genetic and epigenetic studies, discuss the strengths and weaknesses of the study and speculate on the future of epigenetics in chronic disease research. See research article: http://www.biomedcentral.com/1741-7015/8/87/abstract

Impact of physical activity and doping on epigenetic gene regulation.

Science.gov (United States)

Schwarzenbach, Heidi

2011-10-01

To achieve success in sports, many athletes consume doping substances, such as anabolic androgenic steroids and growth hormones, and ignore the negative influence of these drugs on their health. Apart from the unethical aspect of doping in sports, it is essential to consider the tremendous risk it represents to their physical condition. The abuse of pharmaceuticals which improve athletic performance may alter the expression of specific genes involved in muscle and bone metabolism by epigenetic mechanisms, such as DNA methylation and histone modifications. Moreover, excessive and relentless training to increase the muscle mass, may also have an influence on the health of the athletes. This stress releases neurotransmitters and growth factors, and may affect the expression of endogenous genes by DNA methylation, too. This paper focuses on the relationship between epigenetic mechanisms and sports, highlights the potential consequences of abuse of doping drugs on gene expression, and describes methods to molecularly detect epigenetic changes of gene markers reflecting the physiological or metabolic effects of doping agents. Copyright © 2011 John Wiley & Sons, Ltd.

Epigenetics and cancer: implications for drug discovery and safety assessment

International Nuclear Information System (INIS)

Moggs, Jonathan G.; Goodman, Jay I.; Trosko, James E.; Roberts, Ruth A.

2004-01-01

It is necessary to determine whether chemicals or drugs have the potential to pose a threat to human health. Research conducted over the last two decades has led to the paradigm that chemicals can cause cancer either by damaging DNA or by altering cellular growth, probably via receptor-mediated changes in gene expression. However, recent evidence suggests that gene expression can be altered markedly via several diverse epigenetic mechanisms that can lead to permanent or reversible changes in cellular behavior. Key molecular events underlying these mechanisms include the alteration of DNA methylation and chromatin, and changes in the function of cell surface molecules. Thus, for example, DNA methyltransferase enzymes together with chromatin-associated proteins such as histone modifying enzymes and remodelling factors can modify the genetic code and contribute to the establishment and maintenance of altered epigenetic states. This is relevant to many types of toxicity including but not limited to cancer. In this paper, we describe the potential for interplay between genetic alteration and epigenetic changes in cell growth regulation and discuss the implications for drug discovery and safety assessment

Cancer Control and Prevention by Nutrition and Epigenetic Approaches

OpenAIRE

Verma, Mukesh

2012-01-01

Significance: Epigenetics involves alterations in gene expression without changing the nucleotide sequence. Because some epigenetic changes can be reversed chemically, epigenetics has tremendous implications for disease intervention and treatment. Recent Advances: After epigenetic components in cancer were characterized, genes and pathways are being characterized in other diseases such as diabetes, obesity, and neurological disorders. Observational, experimental, and clinical studies in diffe...

Epigenetic variation in asexually reproducing organisms

NARCIS (Netherlands)

Verhoeven, K.J.F.; Preite, V.

2014-01-01

The role that epigenetic inheritance can play in adaptation may differ between sexuals and asexuals because (1) the dynamics of adaptation differ under sexual and asexual reproduction and the opportunities offered by epigenetic inheritance may affect these dynamics differently; and (2) in asexual

Epigenetic regulation of the transcription factor Foxa2 directs differential elafin expression in melanocytes and melanoma cells

Energy Technology Data Exchange (ETDEWEB)

Yu, Kyung Sook [Therapeutic Antibody Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806 (Korea, Republic of); Jo, Ji Yoon; Kim, Su Jin [Therapeutic Antibody Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806 (Korea, Republic of); Department of Functional Genomics, University of Science and Technology, Daejeon 305-333 (Korea, Republic of); Lee, Yangsoon [Therapeutic Antibody Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806 (Korea, Republic of); Bae, Jong Hwan [NeoPharm Co. Ltd., Daejeon 305-510 (Korea, Republic of); Chung, Young-Hwa [Department of Cogno-Mechatronics Engineering, BK21 Nanofusion Technology Team, Pusan National University, Busan 609-736 (Korea, Republic of); Koh, Sang Seok, E-mail: sskoh@kribb.re.kr [Therapeutic Antibody Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806 (Korea, Republic of); Department of Functional Genomics, University of Science and Technology, Daejeon 305-333 (Korea, Republic of)

2011-04-29

Highlights: {yields} Elafin expression is epigenetically silenced in human melanoma cells. {yields} Foxa2 expression in melanoma cells is silenced by promoter hypermethylation. {yields} Foxa2 directs activation of the elafin promoter in vivo. {yields} Foxa2 expression induces apoptosis of melanoma cells via elafin re-expression. -- Abstract: Elafin, a serine protease inhibitor, induces the intrinsic apoptotic pathway in human melanoma cells, where its expression is transcriptionally silenced. However, it remains unknown how the elafin gene is repressed in melanoma cells. We here demonstrate that elafin expression is modulated via epigenetically regulated expression of the transcription factor Foxa2. Treatment of melanoma cells with a DNA methyltransferase inhibitor induced elafin expression, which was specifically responsible for reduced proliferation and increased apoptosis. Suppression of Foxa2 transcription, mediated by DNA hypermethylation in its promoter region, was released in melanoma cells upon treatment with the demethylating agent. Luciferase reporter assays indicated that the Foxa2 binding site in the elafin promoter was critical for the activation of the promoter. Chromatin immunoprecipitation assays further showed that Foxa2 bound to the elafin promoter in vivo. Analyses of melanoma cells with varied levels of Foxa2 revealed a correlated expression between Foxa2 and elafin and the ability of Foxa2 to induce apoptosis. Our results collectively suggest that, in melanoma cells, Foxa2 expression is silenced and therefore elafin is maintained unexpressed to facilitate cell proliferation in the disease melanoma.

Epigenetic Regulation in Prostate Cancer Progression.

Science.gov (United States)

Ruggero, Katia; Farran-Matas, Sonia; Martinez-Tebar, Adrian; Aytes, Alvaro

2018-01-01

An important number of newly identified molecular alterations in prostate cancer affect gene encoding master regulators of chromatin biology epigenetic regulation. This review will provide an updated view of the key epigenetic mechanisms underlying prostate cancer progression, therapy resistance, and potential actionable mechanisms and biomarkers. Key players in chromatin biology and epigenetic master regulators has been recently described to be crucially altered in metastatic CRPC and tumors that progress to AR independency. As such, epigenetic dysregulation represents a driving mechanism in the reprograming of prostate cancer cells as they lose AR-imposed identity. Chromatin integrity and accessibility for transcriptional regulation are key features altered in cancer progression, and particularly relevant in nuclear hormone receptor-driven tumors like prostate cancer. Understanding how chromatin remodeling dictates prostate development and how its deregulation contributes to prostate cancer onset and progression may improve risk stratification and treatment selection for prostate cancer patients.

Epigenetics in Prostate Cancer

Directory of Open Access Journals (Sweden)

Costantine Albany

2011-01-01

Full Text Available Prostate cancer (PC is the most commonly diagnosed nonskin malignancy and the second most common cause of cancer death among men in the United States. Epigenetics is the study of heritable changes in gene expression caused by mechanisms other than changes in the underlying DNA sequences. Two common epigenetic mechanisms, DNA methylation and histone modification, have demonstrated critical roles in prostate cancer growth and metastasis. DNA hypermethylation of cytosine-guanine (CpG rich sequence islands within gene promoter regions is widespread during neoplastic transformation of prostate cells, suggesting that treatment-induced restoration of a “normal” epigenome could be clinically beneficial. Histone modification leads to altered tumor gene function by changing chromosome structure and the level of gene transcription. The reversibility of epigenetic aberrations and restoration of tumor suppression gene function have made them attractive targets for prostate cancer treatment with modulators that demethylate DNA and inhibit histone deacetylases.

Epigenetic regulation of hematopoietic stem cell aging

International Nuclear Information System (INIS)

Beerman, Isabel; Rossi, Derrick J.

2014-01-01

Aging is invariably associated with alterations of the hematopoietic stem cell (HSC) compartment, including loss of functional capacity, altered clonal composition, and changes in lineage contribution. Although accumulation of DNA damage occurs during HSC aging, it is unlikely such consistent aging phenotypes could be solely attributed to changes in DNA integrity. Another mechanism by which heritable traits could contribute to the changes in the functional potential of aged HSCs is through alterations in the epigenetic landscape of adult stem cells. Indeed, recent studies on hematopoietic stem cells have suggested that altered epigenetic profiles are associated with HSC aging and play a key role in modulating the functional potential of HSCs at different stages during ontogeny. Even small changes of the epigenetic landscape can lead to robustly altered expression patterns, either directly by loss of regulatory control or through indirect, additive effects, ultimately leading to transcriptional changes of the stem cells. Potential drivers of such changes in the epigenetic landscape of aged HSCs include proliferative history, DNA damage, and deregulation of key epigenetic enzymes and complexes. This review will focus largely on the two most characterized epigenetic marks – DNA methylation and histone modifications – but will also discuss the potential role of non-coding RNAs in regulating HSC function during aging

Epigenetic regulation of hematopoietic stem cell aging

Energy Technology Data Exchange (ETDEWEB)

Beerman, Isabel, E-mail: isabel.beerman@childrens.harvard.edu [Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138 (United States); Department of Pediatrics, Harvard Medical School, Boston, MA 02115 (United States); Program in Cellular and Molecular Medicine, Division of Hematology/Oncology, Boston Children' s Hospital, MA 02116 (United States); Rossi, Derrick J. [Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138 (United States); Department of Pediatrics, Harvard Medical School, Boston, MA 02115 (United States); Program in Cellular and Molecular Medicine, Division of Hematology/Oncology, Boston Children' s Hospital, MA 02116 (United States)

2014-12-10

Aging is invariably associated with alterations of the hematopoietic stem cell (HSC) compartment, including loss of functional capacity, altered clonal composition, and changes in lineage contribution. Although accumulation of DNA damage occurs during HSC aging, it is unlikely such consistent aging phenotypes could be solely attributed to changes in DNA integrity. Another mechanism by which heritable traits could contribute to the changes in the functional potential of aged HSCs is through alterations in the epigenetic landscape of adult stem cells. Indeed, recent studies on hematopoietic stem cells have suggested that altered epigenetic profiles are associated with HSC aging and play a key role in modulating the functional potential of HSCs at different stages during ontogeny. Even small changes of the epigenetic landscape can lead to robustly altered expression patterns, either directly by loss of regulatory control or through indirect, additive effects, ultimately leading to transcriptional changes of the stem cells. Potential drivers of such changes in the epigenetic landscape of aged HSCs include proliferative history, DNA damage, and deregulation of key epigenetic enzymes and complexes. This review will focus largely on the two most characterized epigenetic marks – DNA methylation and histone modifications – but will also discuss the potential role of non-coding RNAs in regulating HSC function during aging.

Radiation-induced epigenetic alterations after low and high LET irradiations

International Nuclear Information System (INIS)

Aypar, Umut; Morgan, William F.; Baulch, Janet E.

2011-01-01

Epigenetics, including DNA methylation and microRNA (miRNA) expression, could be the missing link in understanding radiation-induced genomic instability (RIGI). This study tests the hypothesis that irradiation induces epigenetic aberrations, which could eventually lead to RIGI, and that the epigenetic aberrations induced by low linear energy transfer (LET) irradiation are different than those induced by high LET irradiations. GM10115 cells were irradiated with low LET X-rays and high LET iron (Fe) ions and evaluated for DNA damage, cell survival and chromosomal instability. The cells were also evaluated for specific locus methylation of nuclear factor-kappa B (NFκB), tumor suppressor in lung cancer 1 (TSLC1) and cadherin 1 (CDH1) gene promoter regions, long interspersed nuclear element 1 (LINE-1) and Alu repeat element methylation, CpG and non-CpG global methylation and miRNA expression levels. Irradiated cells showed increased micronucleus induction and cell killing immediately following exposure, but were chromosomally stable at delayed times post-irradiation. At this same delayed time, alterations in repeat element and global DNA methylation and miRNA expression were observed. Analyses of DNA methylation predominantly showed hypomethylation, however hypermethylation was also observed. We demonstrate that miRNA expression levels can be altered after X-ray irradiation and that these miRNA are involved in chromatin remodeling and DNA methylation. A higher incidence of epigenetic changes was observed after exposure to X-rays than Fe ions even though Fe ions elicited more chromosomal damage and cell killing. This distinction is apparent at miRNA analyses at which only three miRNA involved in two major pathways were altered after high LET irradiations while six miRNA involved in five major pathways were altered after low LET irradiations. This study also shows that the irradiated cells acquire epigenetic changes suggesting that epigenetic aberrations may arise in the

Radiation-induced epigenetic alterations after low and high LET irradiations

Energy Technology Data Exchange (ETDEWEB)

Aypar, Umut, E-mail: uaypa001@umaryland.edu [Department of Radiation Oncology, Radiation Oncology Research Laboratory, University of Maryland School of Medicine, Baltimore, MD 21201 (United States); Morgan, William F. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Baulch, Janet E. [Department of Radiation Oncology, Radiation Oncology Research Laboratory, University of Maryland School of Medicine, Baltimore, MD 21201 (United States)

2011-02-10

Epigenetics, including DNA methylation and microRNA (miRNA) expression, could be the missing link in understanding radiation-induced genomic instability (RIGI). This study tests the hypothesis that irradiation induces epigenetic aberrations, which could eventually lead to RIGI, and that the epigenetic aberrations induced by low linear energy transfer (LET) irradiation are different than those induced by high LET irradiations. GM10115 cells were irradiated with low LET X-rays and high LET iron (Fe) ions and evaluated for DNA damage, cell survival and chromosomal instability. The cells were also evaluated for specific locus methylation of nuclear factor-kappa B (NF{kappa}B), tumor suppressor in lung cancer 1 (TSLC1) and cadherin 1 (CDH1) gene promoter regions, long interspersed nuclear element 1 (LINE-1) and Alu repeat element methylation, CpG and non-CpG global methylation and miRNA expression levels. Irradiated cells showed increased micronucleus induction and cell killing immediately following exposure, but were chromosomally stable at delayed times post-irradiation. At this same delayed time, alterations in repeat element and global DNA methylation and miRNA expression were observed. Analyses of DNA methylation predominantly showed hypomethylation, however hypermethylation was also observed. We demonstrate that miRNA expression levels can be altered after X-ray irradiation and that these miRNA are involved in chromatin remodeling and DNA methylation. A higher incidence of epigenetic changes was observed after exposure to X-rays than Fe ions even though Fe ions elicited more chromosomal damage and cell killing. This distinction is apparent at miRNA analyses at which only three miRNA involved in two major pathways were altered after high LET irradiations while six miRNA involved in five major pathways were altered after low LET irradiations. This study also shows that the irradiated cells acquire epigenetic changes suggesting that epigenetic aberrations may arise

Repressive but not activating epigenetic modifications are aberrant on the inactive X chromosome in live cloned cattle.

Science.gov (United States)

Geng-Sheng, Cao; Yu, Gao; Kun, Wang; Fang-Rong, Ding; Ning, Li

2009-08-01

X inactivation is the process of a chromosome-wide silencing of the majority of genes on the X chromosome during early mammalian development. This process may be aberrant in cloned animals. Here we show that repressive modifications, such as methylation of DNA, and the presence of methylated histones, H3K9me2 and H3K27me3, exhibit distinct aberrance on the inactive X chromosome in live clones. In contrast, H3K4me3, an active gene marker, is obviously missing from the inactive X chromosome in all cattle studied. This suggests that the disappearance of active histone modifications (H3K4me3) seems to be more important for X inactivation than deposition of marks associated with heterochromatin (DNA methylation, H3K27me3 and H3K9me2). It also implies that even apparently normal clones may have subtle abnormalities in repressive, but not activating epigenetic modifications on the inactive X when they survive to term. We also found that the histone H3 methylations were enriched and co-localized at q21-31 of the active X chromosome, which may be associated with an abundance of LINE1 repeat elements. © 2009 The Authors. Journal compilation © 2009 Japanese Society of Developmental Biologists.

Introduction to the Special Section on Epigenetics

Science.gov (United States)

Lester, Barry M.; Conradt, Elisabeth; Marsit, Carmen

2016-01-01

Epigenetics provides the opportunity to revolutionize our understanding of the role of genetics and the environment in explaining human behavior, although the use of epigenetics to study human behavior is just beginning. In this introduction, the authors present the basics of epigenetics in a way that is designed to make this exciting field…

Potential of epigenetic therapies in the management of solid tumors

International Nuclear Information System (INIS)

Valdespino, Victor; Valdespino, Patricia M

2015-01-01

Cancer is a complex disease with both genetic and epigenetic origins. The growing field of epigenetics has contributed to our understanding of oncogenesis and tumor progression, and has allowed the development of novel therapeutic drugs. First-generation epigenetic inhibitor drugs have obtained modest clinical results in two types of hematological malignancy. Second-generation epigenetic inhibitors are in development, and have intrinsically greater selectivity for their molecular targets. Solid tumors are more genetic and epigenetically complex than hematological malignancies, but the transcriptome and epigenome biomarkers have been identified for many of these malignancies. This solid tumor molecular aberration profile may be modified using specific or quasi-specific epidrugs together with conventional and innovative anticancer treatments. In this critical review, we briefly analyze the strategies to select the targeted epigenetic changes, enumerate the second-generation epigenetic inhibitors, and describe the main signs indicating the potential of epigenetic therapies in the management of solid tumors. We also highlight the work of consortia or academic organizations that support the undertaking of human epigenetic therapeutic projects as well as some examples of transcriptome/epigenome profile determination in clinical assessment of cancer patients treated with epidrugs. There is a good chance that epigenetic therapies will be able to be used in patients with solid tumors in the future. This may happen soon through collaboration of diverse scientific groups, making the selection of targeted epigenetic aberration(s) more rapid, the design and probe of drug candidates, accelerating in vitro and in vivo assays, and undertaking new cancer epigenetic-therapy clinical trails

Epigenetic game theory: How to compute the epigenetic control of maternal-to-zygotic transition.

Science.gov (United States)

Wang, Qian; Gosik, Kirk; Xing, Sujuan; Jiang, Libo; Sun, Lidan; Chinchilli, Vernon M; Wu, Rongling

2017-03-01

Epigenetic reprogramming is thought to play a critical role in maintaining the normal development of embryos. How the methylation state of paternal and maternal genomes regulates embryogenesis depends on the interaction and coordination of the gametes of two sexes. While there is abundant research in exploring the epigenetic interactions of sperms and oocytes, a knowledge gap exists in the mechanistic quantitation of these interactions and their impact on embryo development. This review aims at formulating a modeling framework to address this gap through the integration and synthesis of evolutionary game theory and the latest discoveries of the epigenetic control of embryo development by next-generation sequencing. This framework, named epigenetic game theory or epiGame, views embryogenesis as an ecological system in which two highly distinct and specialized gametes coordinate through either cooperation or competition, or both, to maximize the fitness of embryos under Darwinian selection. By implementing a system of ordinary differential equations, epiGame quantifies the pattern and relative magnitude of the methylation effects on embryogenesis by the mechanisms of cooperation and competition. epiGame may gain new insight into reproductive biology and can be potentially applied to design personalized medicines for genetic disorder intervention. Copyright © 2016 Elsevier B.V. All rights reserved.

Epigenetics: A way to bridge the gap between biological fields.

Science.gov (United States)

Nicoglou, Antonine; Merlin, Francesca

2017-12-01

The concept of epigenetics has evolved since Waddington defined it from the late 1930s as the study of the causal mechanisms at work in development. It has become a multi-faceted notion with different meanings, depending on the disciplinary context it is used. In this article, we first analyse the transformations of the concept of epigenetics, from Waddington to contemporary accounts, in order to identify its different meanings and traditions, and to come up with a typology of epigenetics throughout its history. Second, we show on this basis that epigenetics has progressively turned its main focus from biological problems regarding development, toward issues concerning evolution. Yet, both these different epistemological aspects of epigenetics still coexist. Third, we claim that the classical opposition between epigenesis and preformationism as ways of thinking about the developmental process is part of the history of epigenetics and has contributed to its current various meanings. With these objectives in mind, we first show how Waddington introduced the term "epigenetics" in a biological context in order to solve a developmental problem, and we then build on this by presenting Nanney's, Riggs' and Holliday's definitions, which form the basis for the current conception of "molecular epigenetics". Then, we show that the evo-devo research field is where some particular uses of epigenetics have started shifting from developmental issues to evolutionary problems. We also show that epigenetics has progressively focused on the issue of epigenetic inheritance within the Extended Evolutionary Synthesis' framework. Finally, we conclude by presenting a typology of the different conceptions of epigenetics throughout time, and analyse the connections between them. We argue that, since Waddington, epigenetics, as an integrative research area, has been used to bridge the gap between different biological fields. Copyright © 2017 Elsevier Ltd. All rights reserved.

Epigenetic heterochromatin markers distinguish terminally differentiated leukocytes from incompletely differentiated leukemia cells in human blood

Czech Academy of Sciences Publication Activity Database

Popova, Evgenya Y.; Claxton, David F.; Lukášová, Emilie; Bird, Philip I.; Grigoryev, Sergei A.

2006-01-01

Roč. 34, č. 4 (2006), s. 453-462 ISSN 0301-472X R&D Projects: GA AV ČR(CZ) 1QS500040508 Institutional research plan: CEZ:AV0Z50040507 Keywords : terminal cell differentiation * chromatin structure * chronic myeloid leukemia Subject RIV: BO - Biophysics Impact factor: 3.408, year: 2006

Epigenetics and environmental impacts in cattle

Science.gov (United States)

This chapter reviews the major advances in the field of epigenetics as well as the environmental impacts of cattle. Many findings from our own research endeavors related to the topic of this chapter are also introduced. The phenotypic characterization of an animal can be changed through epigenetic ...

Imaging epigenetics in Alzheimer's disease.

Science.gov (United States)

Lista, Simone; Garaci, Francesco G; Toschi, Nicola; Hampel, Harald

2013-01-01

Sporadic Alzheimer's disease (AD) is a prevalent, complex and chronically progressive brain disease. Its course is non-linear, dynamic, adaptive to maladaptive, and compensatory to decompensatory, affecting large-scale neural networks through a plethora of mechanistic and signaling pathway alterations that converge into regional and cell type-specific neurodegeneration and, finally, into clinically overt cognitive and behavioral decline. This decline includes reductions in the activities of daily living, quality of life, independence, and life expectancy. Evolving lines of research suggest that epigenetic mechanisms may play a crucial role during AD development and progression. Epigenetics designates molecular mechanisms that alter gene expression without modifications of the genetic code. This topic includes modifications on DNA and histone proteins, the primary elements of chromatin structure. Accumulating evidence has revealed the relevant processes that mediate epigenetic modifications and has begun to elucidate how these processes are apparently dysregulated in AD. This evidence has led to the clarification of the roles of specific classes of therapeutic compounds that affect epigenetic pathways and characteristics of the epigenome. This insight is accompanied by the development of new methods for studying the global patterns of DNA methylation and chromatin alterations. In particular, high-throughput sequencing approaches, such as next-generation DNA sequencing techniques, are beginning to drive the field into the next stage of development. In parallel, genetic imaging is beginning to answer additional questions through its ability to uncover genetic variants, with or without genome-wide significance, that are related to brain structure, function and metabolism, which impact disease risk and fundamental network-based cognitive processes. Neuroimaging measures can further be used to define AD systems and endophenotypes. The integration of genetic neuroimaging

Epigenetics, Nervous System Tumors, and Cancer Stem Cells

Energy Technology Data Exchange (ETDEWEB)

Qureshi, Irfan A. [Rosyln and Leslie Goldstein Laboratory for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, New York, NY 10461 (United States); Institute for Brain Disorders and Neural Regeneration, Albert Einstein College of Medicine, Bronx, New York, NY 10461 (United States); Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, NY 10461 (United States); Rose F. Kennedy Center for Research on Intellectual and Developmental Disabilities, Albert Einstein College of Medicine, Bronx, New York, NY 10461 (United States); Mehler, Mark F., E-mail: mark.mehler@einstein.yu.edu [Rosyln and Leslie Goldstein Laboratory for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, New York, NY 10461 (United States); Institute for Brain Disorders and Neural Regeneration, Albert Einstein College of Medicine, Bronx, New York, NY 10461 (United States); Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, NY 10461 (United States); Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461 (United States); Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, NY 10461 (United States); Rose F. Kennedy Center for Research on Intellectual and Developmental Disabilities, Albert Einstein College of Medicine, Bronx, New York, NY 10461 (United States)

2011-09-13

Recent advances have begun to elucidate how epigenetic regulatory mechanisms are responsible for establishing and maintaining cell identity during development and adult life and how the disruption of these processes is, not surprisingly, one of the hallmarks of cancer. In this review, we describe the major epigenetic mechanisms (i.e., DNA methylation, histone and chromatin modification, non-coding RNA deployment, RNA editing, and nuclear reorganization) and discuss the broad spectrum of epigenetic alterations that have been uncovered in pediatric and adult nervous system tumors. We also highlight emerging evidence that suggests epigenetic deregulation is a characteristic feature of so-called cancer stem cells (CSCs), which are thought to be present in a range of nervous system tumors and responsible for tumor maintenance, progression, treatment resistance, and recurrence. We believe that better understanding how epigenetic mechanisms operate in neural cells and identifying the etiologies and consequences of epigenetic deregulation in tumor cells and CSCs, in particular, are likely to promote the development of enhanced molecular diagnostics and more targeted and effective therapeutic agents for treating recalcitrant nervous system tumors.

Epigenetics, Nervous System Tumors, and Cancer Stem Cells

International Nuclear Information System (INIS)

Qureshi, Irfan A.; Mehler, Mark F.

2011-01-01

Recent advances have begun to elucidate how epigenetic regulatory mechanisms are responsible for establishing and maintaining cell identity during development and adult life and how the disruption of these processes is, not surprisingly, one of the hallmarks of cancer. In this review, we describe the major epigenetic mechanisms (i.e., DNA methylation, histone and chromatin modification, non-coding RNA deployment, RNA editing, and nuclear reorganization) and discuss the broad spectrum of epigenetic alterations that have been uncovered in pediatric and adult nervous system tumors. We also highlight emerging evidence that suggests epigenetic deregulation is a characteristic feature of so-called cancer stem cells (CSCs), which are thought to be present in a range of nervous system tumors and responsible for tumor maintenance, progression, treatment resistance, and recurrence. We believe that better understanding how epigenetic mechanisms operate in neural cells and identifying the etiologies and consequences of epigenetic deregulation in tumor cells and CSCs, in particular, are likely to promote the development of enhanced molecular diagnostics and more targeted and effective therapeutic agents for treating recalcitrant nervous system tumors

Discussing epigenetics in Southern California

Science.gov (United States)

2012-01-01

With the goal of discussing how epigenetic control and chromatin remodeling contribute to the various processes that lead to cellular plasticity and disease, this symposium marks the collaboration between the Institut National de la Santé et de la Recherche Médicale (INSERM) in France and the University of California, Irvine (UCI). Organized by Paolo Sassone-Corsi (UCI) and held at the Beckman Center of the National Academy of Sciences at the UCI campus December 15–16, 2011, this was the first of a series of international conferences on epigenetics dedicated to the scientific community in Southern California. The meeting also served as the official kick off for the newly formed Center for Epigenetics and Metabolism at the School of Medicine, UCI (http://cem.igb.uci.edu). PMID:22414797

Epigenetic Mechanisms of Depression and Antidepressants Action

Science.gov (United States)

Vialou, Vincent; Feng, Jian; Robison, Alfred J.; Nestler, Eric J.

2013-01-01