TY - JOUR A1 - Schneider, Eberhard A1 - Pliushch, Galyna A1 - El Hajj, Nady A1 - Galetzka, Danuta A1 - Puhl, Alexander A1 - Schorsch, Martin A1 - Frauenknecht, Katrin A1 - Riepert, Thomas A1 - Tresch, Achim A1 - Mueller, Annette M. A1 - Coerdt, Wiltrud A1 - Zechner, Ulrich A1 - Haaf, Thomas T1 - Spatial, temporal and interindividual epigenetic variation of functionally important DNA methylation patterns N2 - DNA methylation is an epigenetic modification that plays an important role in gene regulation. It can be influenced by stochastic events, environmental factors and developmental programs. However, little is known about the natural variation of genespecific methylation patterns. In this study, we performed quantitative methylation analyses of six differentially methylated imprinted genes (H19, MEG3, LIT1, NESP55, PEG3 and SNRPN), one hypermethylated pluripotency gene (OCT4) and one hypomethylated tumor suppressor gene (APC) in chorionic villus, fetal and adult cortex, and adult blood samples. Both average methylation level and range of methylation variation depended on the gene locus, tissue type and/or developmental stage. We found considerable variability of functionally important methylation patterns among unrelated healthy individuals and a trend toward more similar methylation levels in monozygotic twins than in dizygotic twins. Imprinted genes showed relatively little methylation changes associated with aging in individuals who are >25 years. The relative differences in methylation among neighboring CpGs in the generally hypomethylated APC promoter may not only reflect stochastic fluctuations but also depend on the tissue type. Our results are consistent with the view that most methylation variation may arise after fertilization, leading to epigenetic mosaicism. KW - Medizin Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68371 ER - TY - JOUR A1 - Schneider, Eberhard A1 - El Hajj, Nady A1 - Müller, Fabian A1 - Navarro, Bianca A1 - Haaf, Thomas T1 - Epigenetic Dysregulation in the Prefrontal Cortex of Suicide Completers JF - Cytogenetic and Genome Research N2 - The epigenome is thought to mediate between genes and the environment, particularly in response to adverse life experiences. Similar to other psychiatric diseases, the suicide liability of an individual appears to be influenced by many genetic factors of small effect size as well as by environmental stressors. To identify epigenetic marks associated with suicide, which is considered the endpoint of complex gene-environment interactions, we compared the cortex DNA methylation patterns of 6 suicide completers versus 6 non-psychiatric sudden-death controls, using Illumina 450K methylation arrays. Consistent with a multifactorial disease model, we found DNA methylation changes in a large number of genes, but no changes with large effects reaching genome-wide significance. Global methylation of all analyzed CpG sites was significantly (0.25 percentage point) lower in suicide than in control brains, whereas the vast majority (97%) of the top 1,000 differentially methylated regions (DMRs) were higher methylated (0.6 percentage point) in suicide brains. Annotation analysis of the top 1,000 DMRs revealed an enrichment of differentially methylated promoters in functional categories associated with transcription and expression in the brain. In addition, we performed a comprehensive literature research to identify suicide genes that have been replicated in independent genetic association, brain methylation and/or expression studies. Although, in general, there was no significant overlap between different published data sets or between our top 1,000 DMRs and published data sets, our methylation screen strengthens a number of candidate genes (APLP2, BDNF, HTR1A, NUAK1, PHACTR3, MSMP, SLC6A4, SYN2, and SYNE2) and supports a role for epigenetics in the pathophysiology of suicide. KW - Cortex KW - DNA methylation KW - Suicidal behavior KW - Transcription regulation Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-199032 SN - 1424-8581 SN - 1424-859X VL - 146 IS - 1 ER - TY - JOUR A1 - Schneider, Eberhard A1 - El Hajj, Nady A1 - Haaf, Thomas T1 - Epigenetic Information from Ancient DNA Provides New Insights into Human Evolution BT - Commentary on Gokhman D et al. (2014): Reconstructing the DNA Methylation Maps of the Neanderthal and the Denisovan. Science 344:523–527 JF - Brain, Behavior and Evolution N2 - No abstract available. KW - human evolution KW - Neanderthal Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-196800 SN - 0006-8977 SN - 1421-9743 N1 - This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively. VL - 84 IS - 3 ER - TY - JOUR A1 - Schneider, Eberhard A1 - Dittrich, Marcus A1 - Böck, Julia A1 - Nanda, Indrajit A1 - Müller, Tobias A1 - Seidmann, Larissa A1 - Tralau, Tim A1 - Galetzka, Danuta A1 - El Hajj, Nady A1 - Haaf, Thomas T1 - CpG sites with continuously increasing or decreasing methylation from early to late human fetal brain development JF - Gene N2 - Normal human brain development is dependent on highly dynamic epigenetic processes for spatial and temporal gene regulation. Recent work identified wide-spread changes in DNA methylation during fetal brain development. We profiled CpG methylation in frontal cortex of 27 fetuses from gestational weeks 12-42, using Illumina 450K methylation arrays. Sites showing genome-wide significant correlation with gestational age were compared to a publicly available data set from gestational weeks 3-26. Altogether, we identified 2016 matching developmentally regulated differentially methylated positions (m-dDMPs): 1767 m-dDMPs were hypermethylated and 1149 hypomethylated during fetal development. M-dDMPs are underrepresented in CpG islands and gene promoters, and enriched in gene bodies. They appear to cluster in certain chromosome regions. M-dDMPs are significantly enriched in autism-associated genes and CpGs. Our results promote the idea that reduced methylation dynamics during fetal brain development may predispose to autism. In addition, m-dDMPs are enriched in genes with human-specific brain expression patterns and/or histone modifications. Collectively, we defined a subset of dDMPs exhibiting constant methylation changes from early to late pregnancy. The same epigenetic mechanisms involving methylation changes in cis-regulatory regions may have been adopted for human brain evolution and ontogeny. KW - Autism spectrum disorders KW - DNA methylation KW - Genome KW - Autism KW - Frontal cortex KW - Human prefrontal cortex KW - Gene-expression KW - Schizophrenia KW - Patterns KW - Transcription KW - Epigenetics KW - Environment KW - Fetal brain development KW - DNA methylation dynamics KW - Methylome Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-186936 VL - 592 IS - 1 ER - TY - JOUR A1 - Prelog, Martina A1 - Hilligardt, Deborah A1 - Schmidt, Christian A. A1 - Przybylski, Grzegorz K. A1 - Leierer, Johannes A1 - Almanzar, Giovanni A1 - El Hajj, Nady A1 - Lesch, Klaus-Peter A1 - Arolt, Volker A1 - Zwanzger, Peter A1 - Haaf, Thomas A1 - Domschke, Katharina T1 - Hypermethylation of FOXP3 Promoter and Premature Aging of the Immune System in Female Patients with Panic Disorder? JF - PLoS ONE N2 - Immunological abnormalities associated with pathological conditions, such as higher infection rates, inflammatory diseases, cancer or cardiovascular events are common in patients with panic disorder. In the present study, T cell receptor excision circles (TRECs), Forkhead-Box-Protein P3 gene (FOXP3) methylation of regulatory T cells (Tregs) and relative telomere lengths (RTLs) were investigated in a total and subsamples of 131 patients with panic disorder as compared to 131 age- and sex-matched healthy controls in order to test for a potential dysfunction and premature aging of the immune system in anxiety disorders. Significantly lower TRECs (p = 0.004) as well as significant hypermethylation of the FOXP3 promoter region (p = 0.005) were observed in female (but not in male) patients with panic disorder as compared to healthy controls. No difference in relative telomere length was discerned between patients and controls, but significantly shorter telomeres in females, smokers and older persons within the patient group. The presently observed reduced TRECs in panic disorder patients and FOXP3 hypermethylation in female patients with panic disorder potentially reflect impaired thymus and immunosuppressive Treg function, which might partly account for the known increased morbidity and mortality of anxiety disorders conferred by e.g. cancer and cardiovascular disorders. KW - DNA methylation KW - antidepressants KW - regulatory T cells KW - panic disorder KW - treatment guidelines KW - telomere length KW - inflammatory diseases KW - anxiety disorders Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-179684 VL - 11 IS - 6 ER - TY - JOUR A1 - Pfeiffer, Susanne A1 - Krüger, Jacqueline A1 - Maierhofer, Anna A1 - Böttcher, Yvonne A1 - Klöting, Nora A1 - El Hajj, Nady A1 - Schleinitz, Dorit A1 - Schön, Michael R. A1 - Dietrich, Arne A1 - Fasshauer, Mathias A1 - Lohmann, Tobias A1 - Dreßler, Miriam A1 - Stumvoll, Michael A1 - Haaf, Thomas A1 - Blüher, Matthias A1 - Kovacs, Peter T1 - Hypoxia-inducible factor 3A gene expression and methylation in adipose tissue is related to adipose tissue dysfunction JF - Scientific Reports N2 - Recently, a genome-wide analysis identified DNA methylation of the HIF3A (hypoxia-inducible factor 3A) as strongest correlate of BMI. Here we tested the hypothesis that HIF3A mRNA expression and CpG-sites methylation in adipose tissue (AT) and genetic variants in HIF3A are related to parameters of AT distribution and function. In paired samples of subcutaneous AT (SAT) and visceral AT (VAT) from 603 individuals, we measured HIF3A mRNA expression and analyzed its correlation with obesity and related traits. In subgroups of individuals, we investigated the effects on HIF3A genetic variants on its AT expression (N = 603) and methylation of CpG-sites (N = 87). HIF3A expression was significantly higher in SAT compared to VAT and correlated with obesity and parameters of AT dysfunction (including CRP and leucocytes count). HIF3A methylation at cg22891070 was significantly higher in VAT compared to SAT and correlated with BMI, abdominal SAT and VAT area. Rs8102595 showed a nominal significant association with AT HIF3A methylation levels as well as with obesity and fat distribution. HIF3A expression and methylation in AT are fat depot specific, related to obesity and AT dysfunction. Our data support the hypothesis that HIF pathways may play an important role in the development of AT dysfunction in obesity. KW - gene expression KW - adipose KW - hypoxia-inducible factor 3A KW - adipose tissue dysfunction KW - obesity Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167662 VL - 6 IS - 27969 ER - TY - JOUR A1 - Kuhtz, Juliane A1 - Schneider, Eberhard A1 - El Hajj, Nady A1 - Zimmermann, Lena A1 - Fust, Olga A1 - Linek, Bartosz A1 - Seufert, Rudolf A1 - Hahn, Thomas A1 - Schorsch, Martin A1 - Haaf, Thomas T1 - Epigenetic heterogeneity of developmentally important genes in human sperm: Implications for assisted reproduction outcome JF - Epigenetics N2 - The molecular basis of male infertility is poorly understood, the majority of cases remaining unsolved. The association of aberrant sperm DNA methylation patterns and compromised semen parameters suggests that disturbances in male germline epigenetic reprogramming contribute to this problem. So far there are only few data on the epigenetic heterogeneity of sperm within a given sample and how to select the best sperm for successful infertility treatment. Limiting dilution bisulfite sequencing of small pools of sperm from fertile donors did not reveal significant differences in the occurrence of abnormal methylation imprints between sperm with and without morphological abnormalities. Intracytoplasmic morphologically selected sperm injection was not associated with an improved epigenetic quality, compared to standard intracytoplasmatic sperm injection. Deep bisulfite sequencing (DBS) of 2 imprinted and 2 pluripotency genes in sperm from men attending a fertility center showed that in both samples with normozoospermia and oligoasthenoteratozoospermia (OAT) the vast majority of sperm alleles was normally (de)methylated and the percentage of epimutations (allele methylation errors) was generally low (<1%). However, DBS allowed one to identify and quantify these rare epimutations with high accuracy. Sperm samples not leading to a pregnancy, in particular in the OAT group, had significantly more epimutations in the paternally methylated GTL2 gene than samples leading to a live birth. All 13 normozoospermic and 13 OAT samples leading to a child had <1% GTL2 epimutations, whereas one (7%) of 14 normozoospermic and 7 (50%) of 14 OAT samples without pregnancy displayed 1–14% GTL2 epimutations. KW - ART outcome KW - deep bisulfite sequencing KW - epigenetic heterogeneity KW - GTL2 KW - sperm DNA methylation KW - IMSI KW - ICSI Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-150261 VL - 9 IS - 12 ER - TY - JOUR A1 - Haertle, Larissa A1 - Maierhofer, Anna A1 - Böck, Julia A1 - Lehnen, Harald A1 - Böttcher, Yvonne A1 - Blüher, Matthias A1 - Schorsch, Martin A1 - Potabattula, Ramya A1 - El Hajj, Nady A1 - Appenzeller, Silke A1 - Haaf, Thomas T1 - Hypermethylation of the non-imprinted maternal MEG3 and paternal MEST alleles is highly variable among normal individuals JF - PLoS ONE N2 - Imprinted genes show parent-specific activity (functional haploidy), which makes them particularly vulnerable to epigenetic dysregulation. Here we studied the methylation profiles of oppositely imprinted genes at single DNA molecule resolution by two independent parental allele-specific deep bisulfite sequencing (DBS) techniques. Using Roche (GSJunior) next generation sequencing technology, we analyzed the maternally imprinted MEST promoter and the paternally imprinted MEG3 intergenic (IG) differentially methylated region (DMR) in fetal cord blood, adult blood, and visceral adipose tissue. Epimutations were defined as paternal or maternal alleles with >50% aberrantly (de)methylated CpG sites, showing the wrong methylation imprint. The epimutation rates (range 2–66%) of the paternal MEST and the maternal MEG3 IG DMR allele, which should be completely unmethylated, were significantly higher than those (0–15%) of the maternal MEST and paternal MEG3 alleles, which are expected to be fully methylated. This hypermethylation of the non-imprinted allele (HNA) was independent of parental origin. Very low epimutation rates in sperm suggest that HNA occurred after fertilization. DBS with Illumina (MiSeq) technology confirmed HNA for the MEST promoter and the MEG3 IG DMR, and to a lesser extent, for the paternally imprinted secondary MEG3 promoter and the maternally imprinted PEG3 promoter. HNA leads to biallelic methylation of imprinted genes in a considerable proportion of normal body cells (somatic mosaicism) and is highly variable between individuals. We propose that during development and differentiation maintenance of differential methylation at most imprinting control regions may become to some extent redundant. The accumulation of stochastic and environmentally-induced methylation errors on the non-imprinted allele may increase epigenetic diversity between cells and individuals. KW - DNA methylation KW - genomic imprinting KW - polymerase chain reaction KW - blood KW - epigenetics KW - sequence alignment KW - sperm Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170433 VL - 12 IS - 8 ER - TY - JOUR A1 - Haertle, Larissa A1 - El Hajj, Nady A1 - Dittrich, Marcus A1 - Müller, Tobias A1 - Nanda, Indrajit A1 - Lehnen, Harald A1 - Haaf, Thomas T1 - Epigenetic signatures of gestational diabetes mellitus on cord blood methylation JF - Clinical Epigenetics N2 - Background: Intrauterine exposure to gestational diabetes mellitus (GDM) confers a lifelong increased risk for metabolic and other complex disorders to the offspring. GDM-induced epigenetic modifications modulating gene regulation and persisting into later life are generally assumed to mediate these elevated disease susceptibilities. To identify candidate genes for fetal programming, we compared genome-wide methylation patterns of fetal cord bloods (FCBs) from GDM and control pregnancies. Methods and results: Using Illumina’s 450K methylation arrays and following correction for multiple testing, 65 CpG sites (52 associated with genes) displayed significant methylation differences between GDM and control samples. Four candidate genes, ATP5A1, MFAP4, PRKCH, and SLC17A4, from our methylation screen and one, HIF3A, from the literature were validated by bisulfite pyrosequencing. The effects remained significant after adjustment for the confounding factors maternal BMI, gestational week, and fetal sex in a multivariate regression model. In general, GDM effects on FCB methylation were more pronounced in women with insulin-dependent GDM who had a more severe metabolic phenotype than women with dietetically treated GDM. Conclusions: Our study supports an association between maternal GDM and the epigenetic status of the exposed offspring. Consistent with a multifactorial disease model, the observed FCB methylation changes are of small effect size but affect multiple genes/loci. The identified genes are primary candidates for transmitting GDM effects to the next generation. They also may provide useful biomarkers for the diagnosis, prognosis, and treatment of adverse prenatal exposures. KW - fetal programming KW - insulin treatment KW - DNA methylation KW - fetal cord blood KW - gestational diabetes mellitus Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159459 VL - 9 IS - 28 ER - TY - JOUR A1 - Galetzka, Danuta A1 - Hansmann, Tamara A1 - El Hajj, Nady A1 - Weis, Eva A1 - Irmscher, Benjamin A1 - Ludwig, Marco A1 - Schneider-Rätzke, Brigitte A1 - Kohlschmidt, Nicolai A1 - Beyer, Vera A1 - Bartsch, Oliver A1 - Zechner, Ulrich A1 - Spix, Claudia A1 - Haaf, Thomas T1 - Monozygotic twins discordant for constitutive BRCA1 promoter methylation, childhood cancer and secondary cancer JF - Epigenetics N2 - We describe monozygotic twins discordant for childhood leukemia and secondary thyroid carcinoma. We used bisulfite pyrosequencing to compare the constitutive promoter methylation of BRCA1 and several other tumor suppressor genes in primary fibroblasts. The affected twin displayed an increased BRCA1 methylation (12%), compared with her sister (3%). Subsequent bisulfite plasmid sequencing demonstrated that 13% (6 of 47) BRCA1 alleles were fully methylated in the affected twin, whereas her sister displayed only single CpG errors without functional implications. This between-twin methylation difference was also found in irradiated fibroblasts and untreated saliva cells. The BRCA1 epimutation may have originated by an early somatic event in the affected twin: approximately 25% of her body cells derived from different embryonic cell lineages carry one epigenetically inactivated BRCA1 allele. This epimutation was associated with reduced basal protein levels and a higher induction of BRCA1 after DNA damage. In addition, we performed a genome-wide microarray analysis of both sisters and found several copy number variations, i.e., heterozygous deletion and reduced expression of the RSPO3 gene in the affected twin. This monozygotic twin pair represents an impressive example of epigenetic somatic mosaicism, suggesting a role for constitutive epimutations, maybe along with de novo genetic alterations in recurrent tumor development. KW - BRCA1 KW - childhood cancer KW - DNA Methylation KW - epimutation KW - monozygotic twins KW - secondary cancer KW - somatic mosaicism Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125386 VL - 7 IS - 1 ER - TY - JOUR A1 - Fiedler, David A1 - Hirsch, Daniela A1 - El Hajj, Nady A1 - Yang, Howard H. A1 - Hu, Yue A1 - Sticht, Carsten A1 - Nanda, Indrajit A1 - Belle, Sebastian A1 - Rueschoff, Josef A1 - Lee, Maxwell P. A1 - Ried, Thomas A1 - Haaf, Thomas A1 - Gaiser, Timo T1 - Genome‐wide DNA methylation analysis of colorectal adenomas with and without recurrence reveals an association between cytosine‐phosphate‐guanine methylation and histological subtypes JF - Genes, Chromosomes and Cancer N2 - Aberrant methylation of DNA is supposed to be a major and early driver of colonic adenoma development, which may result in colorectal cancer (CRC). Although gene methylation assays are used already for CRC screening, differential epigenetic alterations of recurring and nonrecurring colorectal adenomas have yet not been systematically investigated. Here, we collected a sample set of formalin‐fixed paraffin‐embedded colorectal low‐grade adenomas (n = 72) consisting of primary adenomas without and with recurrence (n = 59), recurrent adenomas (n = 10), and normal mucosa specimens (n = 3). We aimed to unveil differentially methylated CpG positions (DMPs) across the methylome comparing not only primary adenomas without recurrence vs primary adenomas with recurrence but also primary adenomas vs recurrent adenomas using the Illumina Human Methylation 450K BeadChip array. Unsupervised hierarchical clustering exhibited a significant association of methylation patterns with histological adenoma subtypes. No significant DMPs were identified comparing primary adenomas with and without recurrence. Despite that, a total of 5094 DMPs (false discovery rate <0.05; fold change >10%) were identified in the comparisons of recurrent adenomas vs primary adenomas with recurrence (674; 98% hypermethylated), recurrent adenomas vs primary adenomas with and without recurrence (241; 99% hypermethylated) and colorectal adenomas vs normal mucosa (4179; 46% hypermethylated). DMPs in cytosine‐phosphate‐guanine (CpG) islands were frequently hypermethylated, whereas open sea‐ and shelf‐regions exhibited hypomethylation. Gene ontology analysis revealed enrichment of genes associated with the immune system, inflammatory processes, and cancer pathways. In conclusion, our methylation data could assist in establishing a more robust and reproducible histological adenoma classification, which is a prerequisite for improving surveillance guidelines. KW - adenoma KW - DNA methylation KW - epigenetics KW - histological subtype KW - recurrence Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-212676 VL - 58 IS - 11 SP - 783 EP - 797 ER - TY - JOUR A1 - El Hajj, Nady A1 - Dittrich, Marcus A1 - Böck, Julia A1 - Kraus, Theo F. J. A1 - Nanda, Indrajit A1 - Müller, Tobias A1 - Seidmann, Larissa A1 - Tralau, Tim A1 - Galetzka, Danuta A1 - Schneider, Eberhard A1 - Haaf, Thomas T1 - Epigenetic dysregulation in the developing Down syndrome cortex JF - Epigenetics N2 - Using Illumina 450K arrays, 1.85% of all analyzed CpG sites were significantly hypermethylated and 0.31% hypomethylated in fetal Down syndrome (DS) cortex throughout the genome. The methylation changes on chromosome 21 appeared to be balanced between hypo- and hyper-methylation, whereas, consistent with prior reports, all other chromosomes showed 3-11times more hyper- than hypo-methylated sites. Reduced NRSF/REST expression due to upregulation of DYRK1A (on chromosome 21q22.13) and methylation of REST binding sites during early developmental stages may contribute to this genome-wide excess of hypermethylated sites. Upregulation of DNMT3L (on chromosome 21q22.4) could lead to de novo methylation in neuroprogenitors, which then persists in the fetal DS brain where DNMT3A and DNMT3B become downregulated. The vast majority of differentially methylated promoters and genes was hypermethylated in DS and located outside chromosome 21, including the protocadherin gamma (PCDHG) cluster on chromosome 5q31, which is crucial for neural circuit formation in the developing brain. Bisulfite pyrosequencing and targeted RNA sequencing showed that several genes of PCDHG subfamilies A and B are hypermethylated and transcriptionally downregulated in fetal DS cortex. Decreased PCDHG expression is expected to reduce dendrite arborization and growth in cortical neurons. Since constitutive hypermethylation of PCDHG and other genes affects multiple tissues, including blood, it may provide useful biomarkers for DS brain development and pharmacologic targets for therapeutic interventions. KW - trisomy 21 KW - DNA methylation KW - Down syndrome KW - fetal brain development KW - frontal cortex KW - protocadherin gamma cluster Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-191239 VL - 11 IS - 8 ER - TY - THES A1 - El Hajj, Nady T1 - Epimutations in Germ-Cell and Embryo Development: Possible Consequences for Assisted Reproduction T1 - Epimutationen in der Keimzell- und Embryonalentwicklung : Mögliche Konsequenzen für die assistierte Reproduktion N2 - Assisted reproductive technologies (ART) emerged in the late 1970’s as a therapy for human infertility. Up till now more than 3 million babies have been conceived through ART, demonstrating the safety and efficiency of the technique. Published reports showed an increase in the rate of imprinting disorders (Beckwith Wiedemann Syndrome, Angelman Syndrome, etc.) in babies born after ART. What are the effects imposed through ART and should researchers reassess its safety and implications on the future offspring? Throughout this thesis, I analyzed the methylation patterns of germ cells and embryos to determine whether in vitro maturation and in vitro fertilization have a negative impact on the epigenetic patterns. Furthermore, DNA methylation was compared between sperm of infertile and presumably fertile controls in order to understand whether epigenetic disturbances lead to infertility at the first place. The occurrence of methylation aberrations in germ cells of infertile patients could be transmitted to new-borns and then cause epigenetic disorders. In order to elucidate the imprinting status within single cells, I developed a new technique based on limiting dilution where bisulfite treated DNA is distributed across several wells before amplification. This allowed methylation measurement at the single allele level as well parent of origin detection. In a total of 141 sperm samples from couples undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) including 106 with male factor or combined infertility and 28 with female infertility, I detected a significant correlation between lower quality of semen parameters (sperm count, percentage of abnormal sperm, and percentage of motile sperm) and the rate of imprinting errors. ALU repeats displayed a higher methylation in sperm DNA of patients leading to a pregnancy and live birth, compared to patients in which pregnancy was not achieved or a spontaneous abortion occurred. A discriminant analysis based on ALU methylation allowed correct classification of >70% of cases. Preliminary data from illumina methylation arrays where more than 27,000 CpGs were analyzed determined that only a single CpG site from the open reading frame C14orf93 was significantly different between the infertile and presumably fertile control group. However, further improvements on data normalization might permit detection of other differentially methylated regions. Comparison of embryos after natural conception, in vitro fertilized embryos from superovulated oocytes, and embryos achieved through fertilization of in vitro cultured oocytes revealed no dramatic effect on the imprinting patterns of Igf2r, H19, and Snrpn. Oocyte cryotop vitrification did not result in a dramatic increase of imprinting mutations in oocytes even though the rate of sporadic methylation errors in single Snrpn CpGs were higher within the in-vitrified group. Collectively, the results I will present within this thesis suggest an increase in the rate of imprinting errors within the germ cells of infertile patients, in addition to a decrease in genome wide methylation of ALU repetitive elements. I did not observe a detrimental effect on the methylation patterns of oocytes and the resulting embryos using in vitro maturation of oocytes and/or standard IVF with in vivo grown superovulated oocytes. N2 - Assistierte Reproduktionstechniken (ART) wurden in den späten 1970er Jahren als Therapie für unfruchtbare Paare mit Kinderwunsch etabliert. Bis zum heutigen Tage wurden dank ART weltweit mehr als 3 Millionen Kinder geboren, ein eindrucksvoller Beweis für die Sicherheit und Effizienz dieser Methode. Dennoch zeigen veröffentlichte Studien einen Anstieg in der Rate von Imprinting-Erkrankungen (Beckwith Wiedemann-Syndrom, Angelman-Syndrom, etc.) bei Kindern, die nach assistierter Reproduktion geboren wurden. Es stellt sich die Frage, welche Effekte durch ART ausgelöst werden können und ob eine neue Einschätzung dieser Methode bezüglich ihrer gesundheitlichen Implikationen für künftige Generationen notwendig ist. In dieser Arbeit habe ich mögliche negative Effekte von in vitro-Maturation und -Fertili-sierung auf Methylierungsmuster humaner und muriner Keimzellen, sowie Maus-Embryonen untersucht. Aberrante DNA-Methylierungsmuster in Keimzellen von infertilen Patienten könnten auf die Neugeborenen übertragen werden und epigenetische Erkrankungen zur Folge haben. Ob epigenetische Störungen im Zusammenhang mit Infertilität stehen, wurde außerdem durch den Vergleich der DNA-Methylierung von Spermien infertiler und fertiler Männer untersucht. Um den Imprintigstatus auf Einzelzellebene zu bestimmen, habe ich basierend auf „Limiting Dilution“ eine neue Methode entwickelt. Bei diesem Verfahren wird Bisulfit-behandelte DNA vor der PCR-Amplifikation in mehrere Reaktionsgefässe verdünnt. Dies erlaubt die Methylierungsanalyse einzelner Allele und die Detektion elternspezifischer Methylierungsmuster. Mit insgesamt 141 Sperma-Proben von Paaren, die sich einer in vitro- Fertilisierung (IVF) oder einer Intrazytoplasmischen Spermieninjektion (ICSI) unterzogen hatten, davon 28 mit weiblicher und 106 mit männlicher oder kombinierter Unfruchtbarkeit, konnte ich einen positiven Zusammenhang zwischen der Rate an Imprinting-Fehlern und geringer Sperma-Qualität (gemessen an Standardparametern) ableiten. ALU-Sequenzen zeigten in Spermien-DNA von Patienten mit erfolgreicher Schwangerschaft und Geburt eine höhere Methylierung als von Patienten mit fehlgeschlagener Schwangerschaft oder Spontanabort. Eine auf der ALU-Methylierung basierende Diskriminanzanalyse konnte mehr als 70% aller Fälle korrekt klassifizieren. Vorläufige Daten aus Experimenten mit Illumina Methylierungs-Arrays mit einer Auflösung von mehr als 27.000 CpG-Positionen identifizierten einen signifikanten Gruppenunterschied zwischen Patienten- und Kontrollgruppe für eine CpG-Position innerhalb des offenen Leserahmens C14orf93. Verbesserungen der Datenauswertung (Normalisierung, Testung etc.) sollten die Entdeckung weiterer differenziell methylierter Regionen erlauben. Der Vergleich von Mausembryos aus natürlicher Konzeption, aus in vitro kultivierten und fertilisierten Oozyten und aus in vitro Fertilisation nach Superovulation zeigte keine dramatischen Effekte auf die Imprinting-Muster der geprägten Gene Igf2r, H19 und Snrpn. Das gilt auch für Cryo-Top vitrifizierte Oozyten, wenn auch die Rate sporadischer Methylierungsfehler einzelner CpG-Positionen in Snrpn etwas höher war als in den Kontrollgruppen. Zusammengenommen lassen die in dieser Arbeit präsentieren Resultate auf eine Zunahme an Imprinting-Fehlern und eine genomweite Abnahme der Methylierung repetitiver ALU-Sequenzen in den Keimzellen infertiler Patienten schließen. KW - Reproduktionsmedizin KW - Epigenotypus KW - Mutation KW - assistierte Reproduktion KW - Keimzell- und Embryonalentwicklung KW - Epimutation KW - Epigenetics KW - Asisted Reproduction KW - Imprinting Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-65995 ER - TY - JOUR A1 - Almanzar, Giovanni A1 - Klein, Matthias A1 - Schmalzing, Marc A1 - Hilligardt, Deborah A1 - El Hajj, Nady A1 - Kneitz, Hermann A1 - Wild, Vanessa A1 - Rosenwald, Andreas A1 - Benoit, Sandrine A1 - Hamm, Henning A1 - Tony, Hans-Peter A1 - Haaf, Thomas A1 - Goebeler, Matthias A1 - Prelog, Martina T1 - Disease Manifestation and Inflammatory Activity as Modulators of Th17/Treg Balance and RORC/FoxP3 Methylation in Systemic Sclerosis JF - International Archives of Allergy and Immunology N2 - Background: There is much evidence that T cells are strongly involved in the pathogenesis of localized and systemic forms of scleroderma (SSc). A dysbalance between FoxP3+ regulatory CD4+ T cells (Tregs) and inflammatory T-helper (Th) 17 cells has been suggested. Methods: The study aimed (1) to investigate the phenotypical and functional characteristics of Th17 and Tregs in SSc patients depending on disease manifestation (limited vs. diffuse cutaneous SSc, dcSSc) and activity, and (2) the transcriptional level and methylation status of Th17- and Treg-specific transcription factors. Results: There was a concurrent accumulation of circulating peripheral IL-17-producing CCR6+ Th cells and FoxP3+ Tregs in patients with dcSSc. At the transcriptional level, Th17- and Treg-associated transcription factors were elevated in SSc. A strong association with high circulating Th17 and Tregs was seen with early, active, and severe disease presentation. However, a diminished suppressive function on autologous lymphocytes was found in SSc-derived Tregs. Significant relative hypermethylation was seen at the gene level for RORC1 and RORC2 in SSc, particularly in patients with high inflammatory activity. Conclusions: Besides the high transcriptional activity of T cells, attributed to Treg or Th17 phenotype, in active SSc disease, Tregs may be insufficient to produce high amounts of IL-10 or to control proliferative activity of effector T cells in SSc. Our results suggest a high plasticity of Tregs strongly associated with the Th17 phenotype. Future directions may focus on enhancing Treg functions and stabilization of the Treg phenotype. KW - methylation KW - systemic sclerosis KW - suppression KW - Tregs KW - Th17 Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-196577 SN - 1018-2438 SN - 1423-0097 N1 - This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively. VL - 171 IS - 2 ER -