ERC FUNDED PROJECTS

Autophagy is a fundamental cellular catabolic process deputed to the degradation and recycling of a variety of intracellular materials. Autophagy plays a significant role in multiple human physio-pathological processes and is now emerging as a critical regulator of skeletal development and homeostasis. We have discovered that during postnatal development in mice, the growth factor FGF18 induces autophagy in the chondrocyte cells of the growth plate to regulate the secretion of type II collagen, a major component of cartilaginous extracellular matrix. The FGF signaling pathways play crucial roles during skeletal development and maintenance and are deregulated in many skeletal disorders. Hence our findings may offer the unique opportunity to uncover new molecular mechanisms through which FGF pathways regulate skeletal development and maintenance and to identify new targets for the treatment of FGF-related skeletal disorders. In this grant application we propose to study the role played by the different FGF ligands and receptors on autophagy regulation and to investigate the physiological relevance of these findings in the context of skeletal growth, homeostasis and maintenance. We will also investigate the intracellular machinery that links FGF signalling pathways to the regulation of autophagy. In addition, we generated preliminary data showing an impairment of autophagy in chondrocyte models of Achondroplasia (ACH) and Thanathoporic dysplasia, two skeletal disorders caused by mutations in FGFR3. We propose to study the role of autophagy in the pathogenesis of FGFR3-related dwarfisms and explore the pharmacological modulation of autophagy as new therapeutic approach for achondroplasia. This application, which combines cell biology, mouse genetics and pharmacological approaches, has the potential to shed light on new mechanisms involved in organismal development and homeostasis, which could be targeted to treat bone and cartilage diseases.

1 586 430 €

Start date: 2017-01-01, End date: 2021-12-31

Acute myeloid leukemia (AML) is a group of hematologic malignancies which, due to their molecular and clinical heterogeneity, have been traditionally difficult to classify and treat. Recently, next-generation, whole-genome sequencing has uncovered several recurrent somatic mutations that better define the landscape of AML genomics. Despite these advances in deciphering AML molecular subsets, there have been no concurrent improvements in AML therapy which still relies on the ‘antracycline+cytarabine’ scheme. Hereto, only about 40-50% of adult young patients are cured whilst most of the elderly succumb to their disease. Therefore, new therapeutic approaches which would take advantage of the new discoveries are clearly needed. In the past years, we discovered and characterized nucleophosmin (NPM1) mutations as the most frequent genetic alteration (about 30%) in AML, and today NPM1-mutated AML is a new entity in the WHO classification of myeloid neoplasms. However, mechanisms of leukemogenesis and a specific therapy for this leukemia are missing. Here, I aim to unravel the complex network of molecular interactions that take place in this distinct genetic subtype, and find their vulnerabilities to identify new targets for therapy. To address this issue, I will avail of relevant pre-clinical models developed in our laboratories and propose two complementary strategies: 1) a screening-based approach, focused either on the target, by analyzing synthetic lethal interactions through CRISPR-based genome-wide interference, or on the drug, by high-throughput chemical libraries screenings; 2) a hypothesis-driven approach, based on our recent gained novel insights on the role of specific intracellular pathways/genes in NPM1-mutated AML and on pharmacological studies with ‘old’ drugs, which we have revisited in the specific AML genetic context. I expect our discoveries will lead to find novel therapeutic approaches and make clinical trials available to patients as soon as possible.

1 883 750 €

Start date: 2017-04-01, End date: 2022-03-31

G protein-coupled receptors make up both the largest membrane protein and drug target families. DE-ORPHAN aims to determine the close functional context; specifically physiological agonists and signaling pathways; and provide the first research tool compounds, of orphan peptide receptors. Determination of physiological agonists (aka de-orphanization), by high-throughput screening has largely failed. We will introduce a new research strategy: 1) developing highly innovative bioinformatics methods for handpicking of all orphan receptor targets and candidate ligand screening libraries; and 2) employing a screening technique that can measure all signaling pathways simultaneously. The first potent and selective pharmacological tool compounds will be identified by chemoinformatic design of focused screening libraries. We will establish the ligands’ structure-activity relationships important for biological activity and further optimization towards drugs. The first potent and selective Gs- and G12/13 protein inhibitors will be designed by structure-based re-optimization from a recent crystal structure of a Gq-inhibitor complex, and applied to determine orphan receptor signaling pathways and ligand pathway-bias. They will open up for efficient dissection of important signaling networks and development of drugs with fewer side effects. DE-ORPHANs design hypotheses are based on unique computational methods to analyze protein and ligand similarities and are founded on genomic and protein sequences, structural data and ligands. The interdisciplinary research strategy applies multiple ligands acting independently but in concert to provide complementary receptor characterization. The results will allow the research field to advance into studies of receptor functions and exploitation of druggable targets, ligands and mechanisms. Which physiological insights and therapeutic breakthroughs will we witness when these receptors find their place in human pharmacology and medicine?

1 499 926 €

Start date: 2015-05-01, End date: 2020-04-30

The activities of the Polycomb group (PcG) of repressive chromatin modifiers are required to maintain correct transcriptional identity during development and differentiation. These activities are altered in a variety of tumours by gain- or loss-of-function mutations, whose mechanistic aspects still remain unclear. PcGs can be classified in two major repressive complexes (PRC1 and PRC2) with common pathways but distinct biochemical activities. PRC1 catalyses histone H2A ubiquitination of lysine 119, and PRC2 tri-methylation of histone H3 lysine 27. However, PRC1 has a more heterogeneous composition than PRC2, with six mutually exclusive PCGF subunits (PCGF1–6) essential for assembling distinct PRC1 complexes that differ in subunit composition but share the same catalytic core. While up to six different PRC1 forms can co-exist in a given cell, the molecular mechanisms regulating their activities and their relative contributions to general PRC1 function in any tissue/cell type remain largely unknown. In line with this biochemical heterogeneity, PRC1 retains broader biological functions than PRC2. Critically, however, no molecular analysis has yet been published that dissects the contribution of each PRC1 complex in regulating transcriptional identity. We will take advantage of newly developed reagents and unpublished genetic models to target each of the six Pcgf genes in either embryonic stem cells or mouse adult tissues. This will systematically dissect the contributions of the different PRC1 complexes to chromatin profiles, gene expression programs, and cellular phenotypes during stem cell self-renewal, differentiation and adult tissue homeostasis. Overall, this will elucidate some of the fundamental mechanisms underlying the establishment and maintenance of cellular identity and will allow us to further determine the molecular links between PcG deregulation and cancer development in a tissue- and/or cell type–specific manner.

2 000 000 €

Start date: 2017-11-01, End date: 2022-10-31