@article{VonaMazaheriLinetal.2021, author = {Vona, Barbara and Mazaheri, Neda and Lin, Sheng-Jia and Dunbar, Lucy A. and Maroofian, Reza and Azaiez, Hela and Booth, Kevin T. and Vitry, Sandrine and Rad, Aboulfazl and R{\"u}schendorf, Franz and Varshney, Pratishtha and Fowler, Ben and Beetz, Christian and Alagramam, Kumar N. and Murphy, David and Shariati, Gholamreza and Sedaghat, Alireza and Houlden, Henry and Petree, Cassidy and VijayKumar, Shruthi and Smith, Richard J. H. and Haaf, Thomas and El-Amraoui, Aziz and Bowl, Michael R. and Varshney, Gaurav K. and Galehdari, Hamid}, title = {A biallelic variant in CLRN2 causes non-syndromic hearing loss in humans}, series = {Human Genetics}, volume = {140}, journal = {Human Genetics}, number = {6}, issn = {1432-1203}, doi = {10.1007/s00439-020-02254-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-267740}, pages = {915-931}, year = {2021}, abstract = {Deafness, the most frequent sensory deficit in humans, is extremely heterogeneous with hundreds of genes involved. Clinical and genetic analyses of an extended consanguineous family with pre-lingual, moderate-to-profound autosomal recessive sensorineural hearing loss, allowed us to identify CLRN2, encoding a tetraspan protein, as a new deafness gene. Homozygosity mapping followed by exome sequencing identified a 14.96 Mb locus on chromosome 4p15.32p15.1 containing a likely pathogenic missense variant in CLRN2 (c.494C > A, NM_001079827.2) segregating with the disease. Using in vitro RNA splicing analysis, we show that the CLRN2 c.494C > A variant leads to two events: (1) the substitution of a highly conserved threonine (uncharged amino acid) to lysine (charged amino acid) at position 165, p.(Thr165Lys), and (2) aberrant splicing, with the retention of intron 2 resulting in a stop codon after 26 additional amino acids, p.(Gly146Lysfs*26). Expression studies and phenotyping of newly produced zebrafish and mouse models deficient for clarin 2 further confirm that clarin 2, expressed in the inner ear hair cells, is essential for normal organization and maintenance of the auditory hair bundles, and for hearing function. Together, our findings identify CLRN2 as a new deafness gene, which will impact future diagnosis and treatment for deaf patients.}, language = {en} } @article{MaierhoferFlunkertDittrichetal.2017, author = {Maierhofer, Anna and Flunkert, Julia and Dittrich, Marcus and M{\"u}ller, Tobias and Schindler, Detlev and Nanda, Indrajit and Haaf, Thomas}, title = {Analysis of global DNA methylation changes in primary human fibroblasts in the early phase following X-ray irradiation}, series = {PLoS ONE}, volume = {12}, journal = {PLoS ONE}, number = {5}, doi = {10.1371/journal.pone.0177442}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170895}, pages = {e0177442}, year = {2017}, abstract = {Epigenetic alterations may contribute to the generation of cancer cells in a multi-step process of tumorigenesis following irradiation of normal body cells. Primary human fibroblasts with intact cell cycle checkpoints were used as a model to test whether X-ray irradiation with 2 and 4 Gray induces direct epigenetic effects (within the first cell cycle) in the exposed cells. ELISA-based fluorometric assays were consistent with slightly reduced global DNA methylation and hydroxymethylation, however the observed between-group differences were usually not significant. Similarly, bisulfite pyrosequencing of interspersed LINE-1 repeats and centromeric α-satellite DNA did not detect significant methylation differences between irradiated and non-irradiated cultures. Methylation of interspersed ALU repeats appeared to be slightly increased (one percentage point; p = 0.01) at 6 h after irradiation with 4 Gy. Single-cell analysis showed comparable variations in repeat methylation among individual cells in both irradiated and control cultures. Radiation-induced changes in global repeat methylation, if any, were much smaller than methylation variation between different fibroblast strains. Interestingly, α-satellite DNA methylation positively correlated with gestational age. Finally, 450K methylation arrays mainly targeting genes and CpG islands were used for global DNA methylation analysis. There were no detectable methylation differences in genic (promoter, 5' UTR, first exon, gene body, 3' UTR) and intergenic regions between irradiated and control fibroblast cultures. Although we cannot exclude minor effects, i.e. on individual CpG sites, collectively our data suggest that global DNA methylation remains rather stable in irradiated normal body cells in the early phase of DNA damage response.}, language = {en} } @article{HansmannPliushchLeubneretal.2012, author = {Hansmann, Tamara and Pliushch, Galyna and Leubner, Monika and Kroll, Patricia and Endt, Daniela and Gehrig, Andrea and Preisler-Adams, Sabine and Wieacker, Peter and Haaf, Thomas}, title = {Constitutive promoter methylation of BRCA1 and RAD51C in patients with familial ovarian cancer and early-onset sporadic breast cancer}, series = {Human Molecular Genetics}, volume = {21}, journal = {Human Molecular Genetics}, number = {21}, doi = {10.1093/hmg/dds308}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125673}, pages = {4669-4679}, year = {2012}, abstract = {Genetic defects in breast cancer (BC) susceptibility genes, most importantly BRCA1 and BRCA2, account for ∼40\% of hereditary BC and ovarian cancer (OC). Little is known about the contribution of constitutive (soma-wide) epimutations to the remaining cases. We developed bisulfite pyrosequencing assays to screen >600 affected BRCA1/BRCA2 mutation-negative patients from the German Consortium for Hereditary Breast and Ovarian Cancer for constitutive hypermethylation of ATM, BRCA1, BRCA2, RAD51C, PTEN and TP53 in blood cells. In a second step, patients with ≥6\% promoter methylation were analyzed by bisulfite plasmid sequencing to demonstrate the presence of hypermethylated alleles (epimutations), indicative of epigenetic gene silencing. Altogether we identified nine (1.4\%) patients with constitutive BRCA1 and three (0.5\%) with RAD51C hypermethylation. Epimutations were found in both sporadic cases, in particular in 2 (5.5\%) of 37 patients with early-onset BC, and familial cases, in particular 4 (10\%) of 39 patients with OC. Hypermethylation was always confined to one of the two parental alleles in a subset (12-40\%) of the analyzed cells. Because epimutations occurred in cell types from different embryonal layers, they most likely originated in single cells during early somatic development. We propose that analogous to germline genetic mutations constitutive epimutations may serve as the first hit of tumor development. Because the role of constitutive epimutations in cancer development is likely to be largely underestimated, future strategies for effective testing of susceptibility to BC and OC should include an epimutation screen.}, language = {en} } @article{SchneiderDittrichBoecketal.2016, author = {Schneider, Eberhard and Dittrich, Marcus and B{\"o}ck, Julia and Nanda, Indrajit and M{\"u}ller, Tobias and Seidmann, Larissa and Tralau, Tim and Galetzka, Danuta and El Hajj, Nady and Haaf, Thomas}, title = {CpG sites with continuously increasing or decreasing methylation from early to late human fetal brain development}, series = {Gene}, volume = {592}, journal = {Gene}, number = {1}, doi = {10.1016/j.gene.2016.07.058}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-186936}, pages = {110-118}, year = {2016}, abstract = {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.}, language = {en} } @article{SchmidSteinleinFeichtingeretal.2014, author = {Schmid, Michael and Steinlein, Claus and Feichtinger, Wolfgang and Haaf, Thomas and Mijares-Urrutia, Abraham and Schargel, Walter E. and Hedges, S. Blair}, title = {Cytogenetic Studies on Gonatodes (Reptilia, Squamata, Sphaerodactylidae)}, series = {Cytogenetic and Genome Research}, volume = {144}, journal = {Cytogenetic and Genome Research}, number = {1}, issn = {1424-8581}, doi = {10.1159/000367929}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196753}, pages = {47-61}, year = {2014}, abstract = {Mitotic and meiotic chromosomes of 5 species of the reptile genus Gonatodes are described by means of conventional staining, banding analyses and in situ hybridization using a synthetic telomeric DNA probe. The amount, location and fluorochrome affinities of constitutive heterochromatin, the number and positions of nucleolus organizer regions, and the patterns of telomeric DNA sequences were determined for most of the species. The karyotypes of G. falconensis and G. taniae from northern Venezuela are distinguished by their extraordinarily reduced diploid chromosome number of 2n = 16, which is the lowest value found so far in reptiles. In contrast to most other reptiles, both species have exclusively large biarmed (meta- and submetacentric) chromosomes. Comparison of the karyotypes of G. falconensis and G. taniae with those of other Gonatodes species indicates that the exceptional 2n = 16 karyotype originated by a series of 8 centric fusions. The karyotypes of G. falconensis and G. taniae are further characterized by the presence of considerable amounts of (TTAGGG)n telomeric sequences in the centromeric regions of all chromosomes. These are probably not only relics of the centric fusion events, but a component of the highly repetitive DNA in the constitutive heterochromatin of the chromosomes. The genome sizes of 4 Gonatodes species were determined using flow cytometry. For comparative purposes, all previously published cytogenetic data on Gonatodes and other sphaerodactylids are included and discussed.}, language = {en} } @article{AlmanzarKleinSchmalzingetal.2016, author = {Almanzar, Giovanni and Klein, Matthias and Schmalzing, Marc and Hilligardt, Deborah and El Hajj, Nady and Kneitz, Hermann and Wild, Vanessa and Rosenwald, Andreas and Benoit, Sandrine and Hamm, Henning and Tony, Hans-Peter and Haaf, Thomas and Goebeler, Matthias and Prelog, Martina}, title = {Disease Manifestation and Inflammatory Activity as Modulators of Th17/Treg Balance and RORC/FoxP3 Methylation in Systemic Sclerosis}, series = {International Archives of Allergy and Immunology}, volume = {171}, journal = {International Archives of Allergy and Immunology}, number = {2}, issn = {1018-2438}, doi = {10.1159/000450949}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196577}, pages = {141-154}, year = {2016}, abstract = {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.}, language = {en} } @article{ElHajjDittrichBoecketal.2016, author = {El Hajj, Nady and Dittrich, Marcus and B{\"o}ck, Julia and Kraus, Theo F. J. and Nanda, Indrajit and M{\"u}ller, Tobias and Seidmann, Larissa and Tralau, Tim and Galetzka, Danuta and Schneider, Eberhard and Haaf, Thomas}, title = {Epigenetic dysregulation in the developing Down syndrome cortex}, series = {Epigenetics}, volume = {11}, journal = {Epigenetics}, number = {8}, doi = {10.1080/15592294.2016.1192736}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-191239}, pages = {563-578}, year = {2016}, abstract = {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.}, language = {en} } @article{SchneiderElHajjMuelleretal.2015, author = {Schneider, Eberhard and El Hajj, Nady and M{\"u}ller, Fabian and Navarro, Bianca and Haaf, Thomas}, title = {Epigenetic Dysregulation in the Prefrontal Cortex of Suicide Completers}, series = {Cytogenetic and Genome Research}, volume = {146}, journal = {Cytogenetic and Genome Research}, number = {1}, issn = {1424-8581}, doi = {10.1159/000435778}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-199032}, pages = {19-27}, year = {2015}, abstract = {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.}, language = {en} } @article{KuhtzSchneiderElHajjetal.2014, author = {Kuhtz, Juliane and Schneider, Eberhard and El Hajj, Nady and Zimmermann, Lena and Fust, Olga and Linek, Bartosz and Seufert, Rudolf and Hahn, Thomas and Schorsch, Martin and Haaf, Thomas}, title = {Epigenetic heterogeneity of developmentally important genes in human sperm: Implications for assisted reproduction outcome}, series = {Epigenetics}, volume = {9}, journal = {Epigenetics}, number = {12}, doi = {10.4161/15592294.2014.988063}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-150261}, pages = {1648-1658}, year = {2014}, abstract = {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.}, language = {en} } @article{SchneiderElHajjHaaf2014, author = {Schneider, Eberhard and El Hajj, Nady and Haaf, Thomas}, title = {Epigenetic Information from Ancient DNA Provides New Insights into Human Evolution}, series = {Brain, Behavior and Evolution}, volume = {84}, journal = {Brain, Behavior and Evolution}, number = {3}, issn = {0006-8977}, doi = {10.1159/000365650}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196800}, pages = {169-171}, year = {2014}, abstract = {No abstract available.}, language = {en} }