ERC FUNDED PROJECTS

In recent years, genome-wide association studies (GWAS) have discovered hundreds of single nucleotide polymorphisms (SNPs) which are significantly associated with coronary artery disease (CAD). However, the SNPs identified by GWAS explain typically only small portion of the trait heritability and vast majority of variants do not have known biological roles. This is explained by variants lying within noncoding regions such as in cell type specific enhancers and additionally ‘the lead SNP’ identified in GWAS may not be the ‘the causal SNP’ but only linked with a trait associated SNP. Therefore, a major priority for understanding disease mechanisms is to understand at the molecular level the function of each CAD loci. In this study we aim to bring the functional characterization of SNPs associated with CAD risk to date by focusing our search for causal SNPs to enhancers of disease relevant cell types, namely endothelial cells, macrophages and smooth muscle cells of the vessel wall, hepatocytes and adipocytes. By combination of massively parallel enhancer activity measurements, collection of novel eQTL data throughout cell types under disease relevant stimuli, identification of the target genes in physical interaction with the candidate enhancers and establishment of correlative relationships between enhancer activity and gene expression we hope to identify causal enhancer variants and link them with target genes to obtain a more complete picture of the gene regulatory events driving disease progression and the genetic basis of CAD. Linking these findings with our deep phenotypic data for cardiovascular risk factors, gene expression and metabolomics has the potential to improve risk prediction, biomarker identification and treatment selection in clinical practice. Ultimately, this research strives for fundamental discoveries and breakthrough that advance our knowledge of CAD and provides pioneering steps towards taking the growing array of GWAS for translatable results.

1 498 647 €

Start date: 2019-01-01, End date: 2023-12-31

The considerable variability within tissue microenvironments as well as the multiclonality of cancers leads to intratumoral heterogeneity. This increases the probablility of cellular states that promote resistance to therapy and eventually lead to reconstitution of the tumor by treatment-resistant cancer cells, which in some cases have properties of normal tissue stem cells. Wnt signals are important in the maintenance of stem cells in various epithelial tissues, including in lung development and regeneration. We hypothesized that Wnt signals contribute to tumor heterogeneity in genetically engineered KrasG12D; Tp53Δ/Δ (”KP”) mouse lung adenocarcinomas (LUAD). We observed that a subpopulation of LUAD cells exhibited high Wnt reporter activity and had increased tumor forming ability, which could be suppressed by silencing of Wnt signaling pathway components or by small molecule Wnt inhibitors in vitro and in vivo. KP LUAD cells show hierarchical features with two distinct populations, one with increased Wnt reporter activity and another forming a niche that provides the Wnt signal. Lineage-tracing experiments in the autochthonous KP tumors demonstrated that Wnt responder cells have increased tumor propagation ability in vivo. Strikingly, selective ablation of the Wnt responder cells resulted in tumor stasis. CRISPR-based targeting or small molecules targeting Wnt signaling reduced tumor growth and prolonged survival in the autochthonous KP mouse lung cancer model. These results indicate that maintenance of heterogeneity within tumors may be advantageous for the tumor cell population collectively. We propose to elucidate the molecular and cellullar mechanisms that control stem-like and niche cell phenotypes using a combination of novel lentiviral vectors and genetically modified mice in the context of the KP LUAD model. These efforts may lead to novel therapeutic concepts in human lung cancer.

1 972 905 €

Start date: 2017-07-01, End date: 2022-06-30

Mitochondria play a central role in the energy metabolism of our bodies and their defects give rise to a large variety of clinical phenotypes that can affect practically any tissue. The mechanisms for the tissue-specific outcomes of mitochondrial diseases are poorly understood. Mitochondrial energy production relies on two separate protein synthesis machineries, cytoplasmic and mitochondrial, but the mechanisms regulating the concerted actions between the two are largely to be discovered. Defects in either protein synthesis system that lead to accumulation of mistranslated mitochondrial proteins, intrinsic or imported from the cytoplasm, result in stress signals from mitochondria and in adaptive responses within the organelle and the entire cell. My hypothesis is that some of these signals and adaptive mechanisms are tissue-specific. My group will test the hypothesis by 1) generating and characterizing mouse models of cytoplasmic and mitochondrial mistranslation to be able to address our questions in different tissues. 2) We will develop methods for detection of ribosome stalling in mouse tissues to identify the consequences of mistranslation for individual proteins. 3) We will use systems biology approaches to identify stress signal responses to mitochondrial and/or cytoplasmic mistranslation using different tissues of our models, to identify those that are unique or global. 4) Our previous study has identified an interesting candidate responder to mistranslation stress and we will test the role of this factor in knockout animal models and by crossing with the mistranslation mice. I expect to gain important new knowledge of in vivo responses to mistranslation and execution of quality control. This proposal investigates key questions in understanding differential tissue involvement in metabolic defects, and will provide new directions for utilization of tissue-specific adaptations in finding interventions for mitochondrial diseases.

1 354 508 €

Start date: 2015-07-01, End date: 2020-06-30