ERC FUNDED PROJECTS

Angiogenesis research has focused on the sprouting of new capillaries. The mechanisms of vessel maturation are much less well understood. Yet, the maintenance of a mature, quiescent, and organotypically-differentiated layer of endothelial cells (ECs) lining the inside of all blood vessels is vital for human health. The goal of ANGIOMATURE is to identify, validate, and implement novel mechanisms of vascular maturation and organotypic EC differentiation that are active during development, maintenance of vascular stability in adults, and undergo changes in aging. We recently identified previously unrecognized gene expression signatures of vascular maturation in a genome-wide screen of ECs isolated from newborn and adult mice. Epigenetic mechanisms were identified that control the EC transcriptome through gain and loss of DNA methylation as well as EC differentiation and signaling specification. These findings pave the way for groundbreaking novel opportunities to study vascular maturation. By characterizing functionally diverse types of blood vessels, including continuous ECs in lung and brain and sinusoidal ECs in liver and bone marrow, the ANGIOMATURE project will (1) determine up to single cell resolution the transcriptional and epigenetic program(s) of vascular maturation and organotypic differentiation during adolescence, (2) analyze the functional consequences of such program(s) in differentiated ECs and their adaptation to challenge, and (3) study changes of maturation and differentiation program(s) and vascular responses during aging. We will towards this end employ an interdisciplinary matrix of approaches involving omics, systems biology, conditional gene targeting, organoid cell culture, and experimental pathology to create a high-resolution structural and functional organotypic angioarchitectural map. The project will thereby yield transformative mechanistic insights into vital biological processes that are most important for human health and healthy aging.

2 338 918 €

Start date: 2018-08-01, End date: 2023-07-31

Despite improved therapy, cardiovascular diseases remain the most prevalent diseases in the European Union and the incidence is rising due to increased obesity and ageing. The fine-tuned regulation of vascular functions is essential not only for preventing atherosclerotic diseases, but also after tissue injury, where the coordinated growth and maturation of new blood vessels provides oxygen and nutrient supply. On the other hand, excessive vessel growth or the generation of immature, leaky vessels contributes to pathological angiogenesis. Thus, the regulation of the complex processes governing vessel growth and maturation has broad impacts for several diseases ranging from tumor angiogenesis, diabetic retinopathy, to ischemic cardiovascular diseases. MicroRNAs (miRs) are small noncoding RNAs, which play a crucial role in embryonic development and tissue homeostasis. However, only limited information is available regarding the role of miRs in the vasculature. MiRs regulate gene expression by binding to the target mRNA leading either to degradation or to translational repression. Because miRs control patterns of target genes, miRs represent an attractive and promising therapeutic target to interfere with complex processes such as neovascularization and repair of ischemic tissues. Therefore, the present application aims to identify miRs in the vasculature, which regulate vessel growth and vessel remodelling and may, thus, serve as therapeutic targets in ischemic diseases. Since ageing critically impairs endothelial function, neovascularization and vascular repair, we will specifically identify miRs, which are dysregulated during ageing in endothelial cells and pro-angiogenic progenitor cells, in order to develop novel strategies to rescue age-induced impairment of neovascularization. Beyond the specific scope of the present application, the principle findings may have impact for other diseases, where deregulated vessel growth causes or accelerates disease states.

2 375 394 €

Start date: 2009-03-01, End date: 2014-02-28

Deregulated apoptotic signaling in hematopoietic stem and progenitor cells (HSPCs) strongly contributes to the pathogenesis and phenotypes of congenital bone marrow failure and myelodysplastic syndromes (MDS) and their progression to acute myeloid leukemia (AML). HSPCs are highly susceptible to apoptosis during bone marrow failure and early MDS, but AML evolution selects for apoptosis resistance. Little is known about the main apoptotic players and their regulators. ApoptoMDS will investigate the impact of apoptotic deregulation for pathogenesis, correlate apoptotic susceptibility with the kinetics of disease progression and characterize the mechanism by which apoptotic susceptibility turns into resistance. ApoptoMDS will draw on a large collection of patient-derived samples and genetically engineered mouse models to investigate disease progression in serially transplanted and xenotransplanted mice. How activated DNA damage checkpoint signaling contributes to syndrome phenotypes and HSPC hypersusceptibility to apoptosis will be assessed. Checkpoint activation confers a competitive disadvantage, and HSPCs undergoing malignant transformation are under high selective pressure to inactivate it. Checkpoint abrogation mitigates the hematological phenotype, but increases the risk of AML evolution. ApoptoMDS aims to analyze if inhibiting apoptosis in HSPCs from bone marrow failure and early-stage MDS can overcome the dilemma of checkpoint abrogation. Whether inhibiting apoptosis is sufficient to improve HSPC function will be tested on several levels and validated in patient-derived samples. How inhibiting apoptosis in the presence of functional checkpoint signaling influences malignant transformation kinetics will be assessed. If, as hypothesized, inhibiting apoptosis both mitigates hematological symptoms and delays AML evolution, ApoptoMDS will pave the way for novel therapeutic approaches to expand the less severe symptomatic period for patients with these syndromes.

1 372 525 €

Start date: 2015-06-01, End date: 2020-05-31

There is an intense interest in the function of human Myc proteins that stems from their pervasive role in the genesis of human tumors. A large body of evidence has established that expression levels of one of three closely related Myc proteins are enhanced in the majority of all human tumors and that multiple tumor entities depend on elevated Myc function, arguing that targeting Myc will have significant therapeutic efficacy. This hope awaits clinical confirmation, since the strategies that are currently under investigation to target Myc function or expression have yet to enter the clinic. Myc proteins are global regulators of transcription, but their mechanism of action is poorly understood. Myc proteins are highly unstable in normal cells and rapidly turned over by the ubiquitin/proteasome system. In contrast, they are stabilized in tumor cells. Work by us and by others has shown that stabilization of Myc is required for tumorigenesis and has identified strategies to destabilize Myc for tumor therapy. This work has also led to the surprising observation that the N-Myc protein, which drives neuroendocrine tumorigenesis, is stabilized by association with the Aurora-A kinase and that clinically available Aurora-A inhibitors can dissociate the complex and destabilize N-Myc. Aurora-A has not previously been implicated in transcription, prompting us to use protein crystallography, proteomics and shRNA screening to understand its interaction with N-Myc. We have now identified a novel protein complex of N-Myc and Aurora-A that provides an unexpected and potentially groundbreaking insight into Myc function. We have also solved the crystal structure of the N-Myc/Aurora-A complex. Collectively, both findings open new strategies to target Myc function for tumor therapy.

2 455 180 €

Start date: 2015-08-01, End date: 2021-04-30