Einfluss von NOD2, intestinalem Mikrobiom und Vitamin D auf den klinischen Verlauf von chronisch-entzündlichen Darmerkrankungen

Der Krankheitsverlauf bei CED-Patienten lässt sich aktuell nur unzureichend vorhersagen, prädiktive Marker stehen nur eingeschränkt zur Verfügung. Die hier vorgestellten Arbeiten beschäftigen sich mit dem Zusammenhang zwischen Darmmikrobiom, Vitamin D und genetischen Risikofaktoren, wie Mutationen im NOD2 Gen bei CED. Aus den hier durchgeführten Untersuchungen resultiert u.a. ein besseres Verständnis darüber, wie sich die einzelnen Faktoren gegenseitig beeinflussen und eine Auswirkung auf den Krankheitsverlauf bei CED haben

Epigenetic characterization of the C3(1) SV40T mouse model of human breast cancer

Breast cancer is a heterogeneous disease, and various subtypes have been defined at the level of gene expression and epigenetic modifications, such as DNA methylation. Epigenetic alterations are attractive candidates for the development of novel biomarkers or as targets for new therapeutic approaches. Mouse models allow monitoring of tumor development from early time points of initiation to final stages of tumorigenesis, but are often poorly characterized with respect to alterations of the epigenetic landscape. Therefore, the aim of this thesis was to generated genome-wide profiles of DNA methylation and histone modifications for the C3(1)SV40TAg (C3(1)) mouse model of basal-like breast cancer and to investigate the epigenetic regulation of long noncoding RNAs. Using a genome-wide screen with Methyl CpG Immunoprecipitation followed by next generation sequencing, we identified several thousand regions with recurrent methylation alterations at different stages of C3(1) tumorigenesis. Differentially methylated genes pointed towards a luminal progenitor as tumor cell of origin in the C3(1) model, and we confirmed a link between DNA methylation and gene expression for five of these genes. Comparisons at the level of promoter methylation revealed general similarity of the C3(1) methylome to human breast cancer. Generation of a chromatin map of the C3(1) model from four histone modifications (H3K4me3, H3K4me1, H3K27ac, H3K27me3) allowed an integrative investigation of methylation changes at breast tissue-specific enhancer regions. We linked tissue-specific alterations of chromatin states in combination with DNA methylation to changes in the expression of genes with importance for mammary gland development and breast cancer. These results unveiled a potential involvement of transcription factors Etv4 (ETS variant 4) and Runx1 (runt related transcription factor 1) in C3(1) tumorigenesis that might help to understand tumor development in basal-like breast cancer. An emerging theme in epigenetic research is the capacity of long noncoding RNAs (lncRNAs) to modulate gene expression by recruitment of gene-silencing or activating complexes. Since regulation of lncRNAs expression is poorly characterized, we investigated DNA methylation changes during carcinogenesis at lncRNA promoters and their influence on neighboring proteincoding genes. Exemplarily, we demonstrated coordinated overexpression of Esrp2 (Epithelial splicing regulatory protein 2) and the lncRNA Esrp2-as (Esrp2-antisense) in C3(1) tumors that was inversely correlated with DNA methylation levels. Knockdown and overexpression of the transcripts did not provide evidence for reciprocal regulation of transcript expression. In contrast, luciferase reporter assays suggested that co-expression of both transcripts is controlled by differential methylation at a common enhancer region. These results are of clinical relevance as high levels of ESRP2 expression in human breast cancer are linked to unfavorable prognosis

Discovery of novel variants underlying inherited bleeding and platelet disorders by next generation sequencing

Genetic variants that affect megakaryopoiesis and platelet formation result in inherited bleeding and platelet disorders (BPD). Only 40-60% of cases will receive a diagnosis indicating the pathway at fault [1, 2]. This thesis is the result of work undertaken to discover novel variants causative of BPD, as part of the NIHR BioResource-Rare Diseases Study (NIHR BR-RD). 1,213 BPD cases of uncertain genetic aetiology were recruited from 31 international centres. 687 samples were sent for whole exome sequencing and 1118 for whole genome sequencing. Cases were systematically phenotyped and genotype-phenotype relationships were assessed to detect causal variants in known and novel candidate BPD genes, including KDSR and ABCC4. KDSR is an early enzyme in the de novo sphingolipid synthetic pathway, and several cases have recently been reported with KDSR variants, severe skin pathology and thrombocytopenia, without evaluation of the mechanism of thrombocytopenia [3, 4]. I report a pedigree in which novel compound heterozygous variants in KDSR cosegregate with a severe phenotype of neonatal-onset thrombocytopenia in two siblings and juvenile myelofibrosis in the older sibling, without significant skin pathology. Cellular studies support roles for KDSR in the regulation of growth and apoptosis, megakaryocyte yield, maturity, size and proplatelet formation. This thesis also reports on the study of a pedigree in which coinheritance of homozygous loss of function variants in novel candidate BPD gene ABCC4 and heterozygous variant in known BPD gene P2RY12 cosegregate with a lifelong mild-to-moderate bleeding disorder. ABCC4 is a membrane-bound transport glycoprotein with broad substrate specificity that includes cAMP, a powerful inhibitor of platelet activation, and intra-platelet cAMP was elevated in affected individuals. The role of ABCC4 in megakaryopoiesis is also explored using CRISPR-Cas9-mediated inhibition of ABCC4 expression in cellular models of megakaryopoiesis. This study describes collaborative approaches to the analysis of high throughput sequencing data for the discovery of potentially pathogenic variants, and emphasises the necessity of functional validation of hypothetical associations

Actes du IXe colloque international sur les textes mycéniens et égéens organisé par le Centre de l'Antiquité Grecque et Romaine de la Fondation Hellénique des Recherches Scientifiques et l'Ecole française d'Athènes, Athènes 2-6 Octobre 1990, Mykenaïka

xx, 673 σ.Ο τόμος καλύπτει θέματα γύρω από μυκηναϊκές επιγραφές. Πιο συγκεκριμένα περιλαμβάνονται ομιλίες σχετικές -μεταξύ άλλων- με τη Γραμμική Α΄, τη Γραμμική Β΄, τα κρητικά ιερογλυφικά, τις επιγραφές της Πύλου, κείμενα και ευρήματα από την Κνωσσό, την Κύπρο και την περιοχή του Αιγαίου