Saarland University Faculty of Medicine
Human Genetics
Head: Prof. Dr. Eckart Meese
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Overview Research Projects

The Institute of Human Genetics analyses questions of tumors genetics and of human genome development. A specific focus is the search for molecular signatures in patients’ blood towards imporved disease diagnosis and monitoring. Due to its inherent stability microRNA (miRNA) is of specific interest for the development of such signatures. These studies are done in collaboration with Prof. Andreas Keller and Prof. Hans-Peter Lenhof at the Center of Bioinformatics in Saarbrücken. MicroRNAs signatures are preferentically determined for patients with lung cancer, brain cancer and nephroblastoma. Besides the tumor specific projects, microRNAs signatures are also analysed in blood of patients with multiple sclerosis and morbus Alzheimer. These studies, which are detailed in the following are supported by the Deutsche Forschungsgemeinschaft, the Deutsche Krebshilfe or  the European Union. Several other research projects at the Institute of Human Genetics, the majority of which is also supported by the aforementioned foundations are detailed in the following. Intramural funding is provided by HOMFOR and the Hedwig Stalter-Stiftung.

 

 

Dr. rer. nat. Masood Abu-Halima

Genetic and epigenetic factors in spermatogenesis

 

Genetic and epigenetic factors play a crucial role in processes leading to male infertility. There is recent evidence that changes of miRNA expression pattern influences genes involved in spermatogenesis.   Specific deregulations of microRNAs have been reported in human testis, spermatozoa and seminal plasma. The project will contribute to our understanding of microRNA changes in physiological spermatogenesis and in spermatogenesis in males with impaired fertility.

 

Publications

 

Dr. rer. nat. Julia Alles

Analysis and validation of microRNA-target interaction networks


The identification of specific microRNA signatures (biomarkers) of blood, serum or tissue samples in health and disease is only one key aspect of our research. Differential expressed microRNAs generally lead to reduced levels of their targets – mostly proteins – which have a substantial impact on a variety of cellular events. Besides internal processes, altered microRNA profiles also affect the interaction and communication between different cell types such as immune cells. We are focusing on complex regulatory networks between microRNAs and their targets and functionally investigate the resulting downstream effects concerning inter- and intracellular consequences.

 

Functional identification of novel microRNAs


Another research focus deals with the characterization of true microRNAs. Computational identification of novel microRNA candidates from NGS datasets is often not accompanied by experimental confirmation which leads to misidentification of other small RNA fragments as microRNAs. By using different experimental approaches, novel microRNA candidates are extensively and clearly validated before they are deposited in open access databases and become subject to signatures specific to diseases and functional analyses (see above).

 

 

Publications

 

PD Dr. rer. nat. Ulrike Fischer

Gene amplifications in tumor cells: developed de novo or adapted from normal cells?


Gene amplifications are a frequent and characteristic marker of human tumors with clinical prognostic value. Gene amplifications are very frequent in human glioblastoma and recent studies document gene amplifications in tumor stem cells especially glioblastoma sphere cells. Interestingly cytogenetic marker of gene amplifications have been identified in mouse neural stem cells almost 20 years ago, but were never characterized further.

Regarding this background following questions arise:

a) Are gene amplifications detectable in mouse neural stem cells?

b) Do gene amplifications exist in human neural stem cells and is there an overlap to gene amplifications found in glioblastoma sphere cells?

c) Is there an overlap between gene amplifications found in neural stem cells and those known to be present in glioblastoma primary tumors?

d) Is there a modification of gene amplifications during differentiation?

 

 

Upstream-effects of gene amplifications in neural progenitor cells during differentiation


During differentiation of human and mouse neural progenitor cells genome-wide gene amplifications were documented. Some of those gene amplifications overlap with amplified chromosome regions known amplified in human glioblastoma. In contrast to gene amplifications in tumors, gene amplification process in neural progenitor cells seems to be restricted to a small time window and a discrete population of cells. There is nothing known on origin of gene amplifications. In addition it is completely unknown how normal cells circumvent strict replication control that allows replication only once per cell cycle. Since gene amplifications were detectable very short after differentiation induction (24h) we speculate that regulatory process must be fast. Regulation with miRNAs is very likely. This project should shed light on miRNA induced gene regulations immediately after differentiation induction using miRNA exprerssion array analysis.

 

Publications

 

Dr. rer. nat. Martin Hart

Functional analysis of microRNAs deregulated in cancer


MicroRNAs (miRNAs) are small (20-23nt), non-coding single-stranded RNAs that posttranscriptionally regulate gene expression at the mRNA level. They control a variety of cellular pathways involved in development, growth, differentiation, proliferation and apoptosis. Hence pathological changes in the miRNA expression pattern contribute to carcinogenesis. At the Institute of Human Genetics we are searching for diagnostic or prognostic biomarkers of lung cancer and Wilms tumor respectively by miRNA microarrays and next generation sequencing. On the basis of these miRNA signatures this project focuses on the identification und functional analysis of miRNA target genes to improve the understanding of carcinogenesis.

 

Publications

 

Dr. rer. nat. Nicole Ludwig

Molecular genetic features in benign meningiomas in recurrence and progression

 

Meningiomas are the most frequent human intracranial tumors and are classified into three histological grades. Although the overwhelming majority of meningiomas are benign meningiomas of WHO grade I, there is a subgroup of meningiomas among these apparently histological benign meningiomas, that tend to recurr and is associated with a worse prognosis. To date, this clinically high relevant subgroup of recurrent meningioma cannot be differentiated from non-recurrent meningiomas by either morphological characteristics or molecular genetic features. With the proposed project, we aim at contributing novel molecular genetic features to identify this highly relevant subgroup of meningiomas. The following questions should be answered in particular: a) Are there molecular genetic features that differentiate recurrent from non-recurrent meningiomas? b) Are there molecular genetic features, that are especially present in the recurrent tumors? c) Which signaling and metabolic pathways are targeted by these features? d) What is the physiological function of these features in the cell? With the proposed project we aim to contribute to the understanding of recurrence in meningioma and to the identification of features essential for meningioma progression.

 

Publications

 

Prof. Dr. rer. nat. Jens Mayer

Analysis of human endogenous retrovirus encoded proteins regarding their relevance for human biology

Human endogenous retrovirus (HERV) sequences comprise about 8% of the human genome. HERV sequences reside in the genome already for millions of years. Several HERV loci are known to exert important biological functions. Some HERVs are evolutionarily younger and still encode former retroviral proteins, such as the so-called HERV-K(HML-2) group. Transcription of HERVs is often deregulated in human disease. Transcription of HERV-K(HML-2) is strongly upregulated in several tumor diseases, among them carcinoma in situ of, and fully manifest, germ cell tumors. Previous work has identified transcribed HERV-K(HML-2) loci encoding active proteins. It is not known whether expression of such HERV-K(HML-2) proteins contributes to tumor development. We employ specifically tailored experimental procedures to examine their relevance for human biology and disease.

 

 

Towards a thorough description of transcribed Human Endogenous Retrovirus loci — and their potential involvement — in Health and Disease

The notion of the human genome is changing. Many more genome regions than previously thought are transcribed into RNA. Identification and further characterization of those transcribed regions, the human transcriptome, will be essential to comprehend its role in health and disease. About 8% of the human genome is comprised of human endogenous retroviruses (HERVs). HERVs contribute significantly to the human transcriptome because of intrinsic promoters and transcriptional regulators. HERV transcripts are found in every human tissue and many HERV loci seem to have retained transcriptional activity. Yet, very little is known about transcriptional activity and regulation of individual HERV loci in health and disease. To better comprehend the contribution of HERVs to the human transcriptome, and their potential roles in human diseases, we will comparatively analyse transcription of HERV loci in normal and diseased human tissues and cell types. Our research will significantly contribute to filling a crucial gap in ongoing international initiatives for characterizing the human transcriptome. Furthermore, our research will also allow to asses the role of transcribed HERVs in regu­lating genes of potential clinical relevance, likely reveal clinical markers on the RNA level and identify clinically relevant genome regions.

 

Publications