@phdthesis{Kollert2021,
  author    = {Kollert, Leonie},
  title     = {Epigenetics of anxiety and depression - a differential role of TGFB-Inducible Early Growth Response Protein 2 gene promoter methylation},
  doi       = {10.25972/OPUS-21126},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-211268},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {Among mental disorders, panic disorder (PD) is one of the most common anxiety disorders characterized by recurring and unexpected episodes of extreme fear i.e. panic attacks. PD displays lifetime prevalence rates in the general population between 2.1-4.7 \% and in about 30 to 40 \% occurs comorbid with major depressive disorder (MDD). Differential methylation levels of the monoamine oxidase A (MAOA) gene have previously been associated with the etiology of both PD and MDD. The TGFB-Inducible Early Growth Response Protein 2 (TIEG2; alias KLF11), an activating transcription factor of the MAOA gene, has been reported to be increased in MDD, but has not yet been investigated in PD on any level. Therefore, in an attempt to further define the role of an impaired TIEG2-MAOA pathway in anxiety and affective disorders, in the present thesis TIEG2 promoter DNA methylation was analyzed in two independent samples of I) PD patients with or without comorbid MDD in a case/control design and II) MDD patients with and without anxious depression. Additionally, in PD patients of sample I), TIEG2 methylation was correlated with Beck Depression Inventory (BDI-II) scores. Finally, in a third independent healthy control sample, correlation of TIEG2 promoter methylation levels with Anxiety Sensitivity Index (ASI) scores as a PD-related measure was analyzed. No overall association of TIEG2 promoter methylation with PD was detected. However, PD patients with comorbid MDD showed significant TIEG2 hypomethylation compared to PD patients without comorbid MDD (p=.008) as well as to healthy controls (p=.010). In addition, MDD patients without anxious features displayed a statistical trend in decreased TIEG2 methylation in comparison to MDD patients with anxious depression (p=.052). Furthermore, TIEG2 methylation was negatively correlated with BDI-II scores in PD patients (p=.013) and positively correlated with ASI scores in the healthy control sample (p=.043). In sum, the current study suggests TIEG2 promoter hypomethylation as a potential epigenetic marker of MDD comorbidity in PD or of non-anxious depression, respectively. If replicated and verified in future studies, altered TIEG2 methylation might therefore represent a differential pathomechanism of anxiety and mood disorders.},
  subject      = {Epigenetik},
  language  = {en}
}
@article{HerzBrehm2019,
  author    = {Herz, Michaela and Brehm, Klaus},
  title     = {Evidence for densovirus integrations into tapeworm genomes},
  series = {Parasites \& Vectors},
  volume    = {12},
  journal   = {Parasites \& Vectors},
  doi       = {10.1186/s13071-019-3820-1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-202478},
  pages     = {560},
  year      = {2019},
  abstract  = {Background Tapeworms lack a canonical piRNA-pathway, raising the question of how they can silence existing mobile genetic elements (MGE). Investigation towards the underlying mechanisms requires information on tapeworm transposons which is, however, presently scarce. Methods The presence of densovirus-related sequences in tapeworm genomes was studied by bioinformatic approaches. Available RNA-Seq datasets were mapped against the Echinococcus multilocularis genome to calculate expression levels of densovirus-related genes. Transcription of densovirus loci was further analyzed by sequencing and RT-qPCR. Results We herein provide evidence for the presence of densovirus-related elements in a variety of tapeworm genomes. In the high-quality genome of E. multilocularis we identified more than 20 individual densovirus integration loci which contain the information for non-structural and structural virus proteins. The majority of densovirus loci are present as head-to-tail concatemers in isolated repeat containing regions of the genome. In some cases, unique densovirus loci have integrated close to histone gene clusters. We show that some of the densovirus loci of E. multilocularis are actively transcribed, whereas the majority are transcriptionally silent. RT-qPCR data further indicate that densovirus expression mainly occurs in the E. multilocularis stem cell population, which probably forms the germline of this organism. Sequences similar to the non-structural densovirus genes present in E. multilocularis were also identified in the genomes of E. canadensis, E. granulosus, Hydatigera taeniaeformis, Hymenolepis diminuta, Hymenolepis microstoma, Hymenolepis nana, Taenia asiatica, Taenia multiceps, Taenia saginata and Taenia solium. Conclusions Our data indicate that densovirus integration has occurred in many tapeworm species. This is the first report on widespread integration of DNA viruses into cestode genomes. Since only few densovirus integration sites were transcriptionally active in E. multilocularis, our data are relevant for future studies into gene silencing mechanisms in tapeworms. Furthermore, they indicate that densovirus-based vectors might be suitable tools for genetic manipulation of cestodes.},
  language  = {en}
}
@phdthesis{Schraut2015,
  author    = {Schraut, Karla-Gerlinde},
  title     = {Epigenetic programming by prenatal stress in female serotonin transporter deficient mice},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120270},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {Early life stress, including exposure to prenatal stress (PS), has been shown to affect the developing brain and induce severe effects on emotional health in later life, concomitant with an increased risk for psychopathology. However, some individuals are more vulnerable to early-life stress, while others adapt successfully, i.e. they are resilient and do not succumb to adversity. The molecular substrates promoting resilience in some individuals and vulnerability in other individuals are as yet poorly investigated. A polymorphism in the serotonin transporter gene (5­HTT/SLC6A4) has been suggested to play a modulatory role in mediating the effects of early-life adversity on psychopathology, thereby rendering carriers of the lower-expressing short (s)-allele more vulnerable to developmental adversity, while long (l)-allele carriers are relatively resilient. The molecular mechanisms underlying this gene x environment interaction (GxE) are not well understood, however, epigenetic mechanisms such as DNA methylation and histone modifications have been discussed to contribute as they are at the interface of environment and the genome. Moreover, developmental epigenetic programming has also been postulated to underlie differential vulnerability/resilience independent of genetic variation. The present work comprises two projects investigating the effects of prenatal maternal restraint stress in 5-HTT deficient mice. In the first study, we examined to which extent previously observed changes in behavior and hippocampal gene expression of female 5-Htt+/- prenatally stressed (PS) offspring were associated with changes in DNA methylation patterns. Additionally, we investigated the expression of genes involved in myelination in hippocampus and amygdala of those animals using RT-qPCR. The genome-wide hippocampal DNA methylation screening was performed using methylated-DNA immunoprecipitation (MeDIP) on Affymetrix GeneChip® Mouse Promoter 1.0R arrays. In order to correlate individual gene-specific DNA methylation, mRNA expression and behavior, we used hippocampal DNA from the same mice as assessed before. 5-Htt genotype, PS and their interaction differentially affected the DNA methylation signature of numerous genes, a part of which were also differentially expressed. More specifically, we identified a differentially methylated region in the Myelin basic protein (Mbp) gene, which was associated with Mbp expression in a 5-Htt-, PS- and 5-Htt x PS-dependent manner. Subsequent fine-mapping linked the methylation status of two specific CpG sites in this region to Mbp expression and anxiety-related behavior. We furthermore found that not only the expression of Mbp but of large gene set associated with myelination was affected by a 5-Htt x PS interaction in a brain-region specific manner. In conclusion, hippocampal DNA methylation patterns and expression profiles of female PS 5-Htt+/- mice suggest that distinct molecular mechanisms, some of which are associated with changes in gene promoter methylation, and processes associated with myelination contribute to the behavioral effects of the 5-Htt genotype, PS exposure, and their interaction. In the second study, we aimed at investing the molecular substrates underlying resilience to PS. For this purpose, we exposed 5-Htt+/+ dams to the same restraint stress paradigm and investigated the effects of PS on depression- and anxiety-like behavior and corticosterone (CORT) secretion at baseline and after acute restraint stress in female 5-Htt+/+ and 5-Htt+/- offspring. We found that PS affected the offspring's social behavior in a negative manner. When specifically examining those PS animals, we grouped the PS offspring of each genotype into a social, resilient and an unsocial, vulnerable group. While anxiety-like behavior in the EPM was reduced in unsocial, but not social, PS 5-Htt+/+ animals when compared to controls, this pattern could not be found in animals of the other genotype, indicating that social anxiety and state anxiety in the EPM were independent of each other. We then assessed genome-wide hippocampal gene expression profiles using mRNA sequencing in order to identify pathways and gene ontology (GO) terms enriched due to 5-Htt genotype (G), PS exposure (E) and their interaction (GxE) as well as enriched in social, but not unsocial, PS offspring, and vice versa. Numerous genes were affected by 5-Htt genotype, PS and most of all a GxE-interaction. Enrichment analysis using enrichr identified that the genotype affected mitochondrial respiration, while GxE-interaction-affected processes associated primarily with myelination and chromatin remodeling. We furthermore found that 5-Htt+/- mice showed profound expression changes of numerous genes in a genomic region located 10 mio kb upstream of the 5 Htt locus on the same chromosome. When looking at social vs. unsocial mice, we found that a much higher number of genes was regulated in 5 Htt+/- animals than in 5-Htt+/+ animals, reflecting the impact of GxE-interaction. Double the number of genes was regulated in social PS vs. control mice when compared to unsocial PS vs. control in both genotypes, suggesting that the successful adaption to PS might have required more active processes from the social group than the reaction to PS from the unsocial group. This notion is supported by the up-regulation of mitochondrial respiration in social, but not in unsocial, PS 5-Htt+/- mice when compared to controls, as those animals might have been able to raise energy resources the unsocial group was not. Next to this, processes associated with myelination seemed to be down-regulated in social 5-Htt+/- mice, but not in unsocial animals, when compared to controls. Taken together, PS exposure affected sociability and anxiety-like behavior dependent on the 5-Htt genotype in female offspring. Processes associated with myelination and epigenetic mechanisms involved in chromatin remodeling seemed be affected in a GxE-dependent manner in the hippocampus of these offspring. Our transcriptome data furthermore suggest that mitochondrial respiration and, with this, energy metabolism might be altered in 5-Htt+/- offspring when compared to 5-Htt+/+ offspring. Moreover, myelination and mitochondrial respiration might contribute to resilience towards PS exposure in 5-Htt+/- offspring, possibly by affecting brain connectivity and energy capabilities.},
  subject      = {Stress},
  language  = {en}
}
@phdthesis{Hofstetter2014,
  author    = {Hofstetter, Christine},
  title     = {Inhibition of H3K27me-Specific Demethylase Activity During Murine ES cell Differentiation Induces DNA Damage Response},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-107023},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2014},
  abstract  = {Stem cells are defined by their capacity to self-renew and their potential to differentiate into multiple cell lineages. Pluripotent embryonic stem (ES) cells can renew indefinitely while keeping the potential to differentiate into any of the three germ layers (ectoderm, endoderm or mesoderm). For decades, ES cells are in the focus of research because of these unique features. When ES cells differentiate they form spheroid aggregates termed "embryoid bodies" (EBs). These EBs mimic post- implantation embryonic development and therefore facilitate the understanding of developmented mechanisms. During ES cell differentiation, de-repression or repression of genes accompanies the changes in chromatin structure. In ES cells, several mechanisms are involved in the regulation of the chromatin architecture, including post-translational modifications of histones. Post-translational histone methylation marks became one of the best- investigated epigenetic modifications, and they are essential for maintaining pluripotency. Until the first histone demethylase KDM1A was discovered in 2004 histone modifications were considered to be irreversible. Since then, a great number of histone demethylases have been identified. Their activity is linked to gene regulation as well as to stem cell self-renewal and differentiation. KDM6A and KDM6B are H3K27me3/2-specific histone demethylases, which are known to play a central role in the regulation of posterior development by regulating HOX gene expression. So far less is known about the molecular function of KDM6A or KDM6B in undifferentiated and differentiating ES cells. In order to completely abrogate KDM6A and KDM6B demethylase activity in undifferentiated and differentiating ES cells, a specific inhibitor (GSK-J4) was employed. Treatment with GSK-J4 had no effect on the viability or proliferation on ES cells. However, in the presence of GSK-J4 ES cell differentiation was completely abrogated with cells arrested in G1-phase and an increased rate of apoptosis. Global transcriptome analyses in early-differentiating ES cells revealed that only a limited set of genes were differentially regulated in response to GSK-J4 treatment with more genes up- regulated than down-regulated. Many of the up-regulated genes are linked to DNA damage response (DDR). In agreement with this, DNA damage was found in EBs incubated with GSK-J4. A co-localization of H3K27me3 or KDM6B with γH2AX foci, marking DNA breaks, could be excluded. However, differentiating Eed knockout (KO) ES cells, which are devoid of the H3K27me3 mark, showed an attenuated GSK-J4- induced DDR. Finally, hematopoietic differentiation in the presence of GSK-J4 resulted in a reduced colony-forming potential. This leads to the conclusion that differentiation in the presence of GSK-J4 is also restricted to hematopoietic differentiation. In conclusion, my results show that the enzymatic activity of KDM6A and KDM6B is not essential for maintaining the pluripotent state of ES cells. In contrast, the enzymatic activity of both proteins is indispensable for ES cell and hematopoietic differentiation. Additionally KDM6A and KDM6B enzymatic inhibition in differentiating ES cells leads to increased DNA damage with an activated DDR. Therefore, KDM6A and KDM6B are associated with DNA damage and in DDR in differentiating ES cells.},
  subject      = {Embryonale Stammzelle},
  language  = {en}
}
@phdthesis{CardosoeCastro2012,
  author    = {Cardoso e Castro, In{\^e}s Sofia},
  title     = {Epigenetic switch induced by MYC in Non-Small-Cell Lung Cancer},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-76713},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2012},
  abstract  = {Non-Small-Cell Lung Cancer (NSCLC) is the most frequent human lung cancer and a major cause of death due to its high rate of metastasis1. These facts emphasize the urgent need for the investigation of new targets for anti-metastatic therapy. Up to now a number of genes and gene products have been identified that positively or negatively affect the probability of established human tumor cell lines to metastasize2. Previously, together with the group of Professor Ulf Rapp, we have described the first conditional mouse model for metastasis of NSCLC and identified a gene, c-MYC, that is able to orchestrate all steps of this process. We could identify potential markers for detection of metastasis and highlighted GATA4, which is exclusively expressed during lung development, as a target for future therapeutic intervention2. However, the mechanism underlying this metastatic conversion remained to be identified, and was therefore the focus of the present work. Here, GATA4 is identified as a MYC target in the development of metastasis and epigenetic alterations at the GATA4 promoter level are shown after MYC expression in NSCLC in vivo and in vitro. Such alterations include site-specific demethylation that accompanies the displacement of the MYC-associated zinc finger protein (MAZ) from the GATA4 promoter, which leads to GATA4 expression. Histone modification analysis of the GATA4 promoter revealed a switch from repressive histone marks to active histone marks after MYC binding, which corresponds to active GATA4 expression. This work identifies a novel epigenetic mechanism by which MYC activates GATA4 leading to metastasis in NSCLC, suggesting novel potential targets for the development of anti-metastatic therapy.},
  subject      = {Nicht-kleinzelliges Bronchialkarzinom},
  language  = {en}
}