ERC FUNDED PROJECTS

Ageing is accompanied by ectopic white adipose tissue depositions in skeletal muscle and other anatomical locations, such as brown adipose tissue and the bone marrow. Ectopic fat accrual contributes to organ dysfunction, systemic insulin resistance, and other perturbations that have been implicated in metabolic diseases. This research proposal aims to identify the regulatory cues that control the development of ectopic progenitor cells that give rise to this type of fat. It is hypothesized that an age-related dysfunction of the stem cell niche leads to an imbalance between (1) tissue-specific stem cells and (2) fibroblast-like, primarily adipogenic progenitors that reside within many tissues. Novel methodologies that assess stem/progenitor cell characteristics on the single cell level will be combined with animal models of lineage tracing to determine the developmental origin of these adipogenic progenitors and processes that regulate their function. Notch signalling is a key signalling pathway that relies on direct physical interaction to control stem cell fate. It is proposed that impaired Notch activity contributes to the phenotypical shift of precursor cell distribution in aged tissues. Lastly, the role of the stem cell niche in ectopic adipocyte progenitor formation will be analyzed. External signals originating from the surrounding niche cells regulate the developmental fate of stem cells. Secreted factors and their role in the formation of ectopic adipocyte precursors during senescence will be identified using a combination of biochemical and systems biology approaches. Accomplishment of these studies will help to understand the basic processes of stem cell ageing and identify mechanisms of age-related functional decline in tissue regeneration. By targeting the population of tissue-resident adipogenic progenitor cells, therapeutic strategies could be developed to counteract metabolic complications associated with the ageing process.

1 496 444 €

Start date: 2013-03-01, End date: 2018-02-28

Acute Myeloid Leukemia (AML), the most common leukemia diagnosed in adults, represents the paradigm of resistance to front-line therapies in hematology. Indeed, AML is so genetically complex that only few targeted therapies are currently tested in this disease and chemotherapy remains the only standard treatment for AML since the past four decades. Despite an initial sustained remission achieved by chemotherapeutic agents, almost all patients relapse with a chemoresistant minimal residual disease (MRD). The goal of my proposal is to characterize the still poorly understood biological mechanisms underlying persistence and emergence of MRD. MRD is the consequence of the re-expansion of leukemia-initiating cells that are intrinsically more resistant to chemotherapy. This cell fraction may be stochastically more prone to survive front-line therapy regardless of their mutational status (the stochastic model), or genetically predetermined to resist by virtue of a collection of chemoprotective mutations (the mutational model). I have already generated in mice, by consecutive rounds of chemotherapy, a stochastic MLL-AF9-driven chemoresistance model that I examined by RNA-sequencing. I will pursue the comprehensive cell autonomous and cell non-autonomous characterization of this chemoresistant AML disease using whole-exome and ChIP-sequencing. To establish a mutationally-induced chemoresistant mouse model, I will conduct an innovative in vivo screen using pooled mutant open reading frame and shRNA libraries in order to predict which combinations of mutations, among those already known in AML, actively promote chemoresistance. Finally, by combining genomic profiling and in vivo shRNA screening experiments, I will decipher the molecular mechanisms and identify the functional effectors of these two modes of resistance. Ultimately, I will then be able to firmly establish the fundamental relevance of the stochastic and/or the mutational model of chemoresistance for MRD genesis.

1 500 000 €

Start date: 2018-03-01, End date: 2023-02-28

New neurons are continuously generated in certain regions of adult mammalian brain. One of those regions is the dentate gyrus, a subregion of hippocampus, which is essential for memory formation. Although these new neurons in the adult dentate gyrus are thought to have an important role in learning and memory, it is largely unclear how new neurons are involved in information processing and storage underlying memory. Because new neurons constitute a minor portion of intermingled local neuronal population, simple application of conventional techniques such as multi-unit extracellular recording and pharmacological lesion are not suitable for the functional analysis of new neurons. In this proposed research program, I will combine multi-unit recording and behavioral analysis with virus mediated, cell-type-specific genetic manipulation of neuronal activity, to investigate computational roles of new neurons in learning and memory. Specifically, I will determine: 1) specific memory processes that require new neurons, 2) dynamic patterns of activity that new neurons express during memory-related behavior, 3) influence of new neurons on their downstream structure. Further, based on the information obtained by these three lines of studies, we will establish causal relationship between specific memory-related behavior and specific pattern of activity in new neurons. Solving these issues will cooperatively provide important insight into the understanding of computational roles performed by adult neurogenesis. The information on the function of new neurons in normal brain could contribute to future development of efficient therapeutic strategy for a variety of brain disorders.

1 991 743 €

Start date: 2009-01-01, End date: 2013-12-31

Blood and lymphatic vessels have been the subject of intense investigation due to their important role in cancer development and in cardiovascular diseases. The significant advance in the methods used to modify and analyse gene function have allowed us to obtain a much better understanding of the molecular mechanisms involved in the regulation of the biology of blood vessels. However, there are two key aspects that significantly diminish our capacity to understand the function of gene networks and their intersections in vivo. One is the long time that is usually required to generate a given double mutant vertebrate tissue, and the other is the lack of single-cell genetic and phenotypic resolution. We have recently performed an in vivo comparative transcriptome analysis of highly angiogenic endothelial cells experiencing different VEGF and Notch signalling levels. These are two of the most important molecular mechanisms required for the adequate differentiation, proliferation and sprouting of endothelial cells. Using the information generated from this analysis, the overall aim of the proposed project is to characterize the vascular function of some of the previously identified genes and determine how they functionally interact with these two signalling pathways. We propose to use novel inducible genetic tools that will allow us to generate a spatially and temporally regulated fluorescent cell mosaic matrix for quantitative analysis. This will enable us to analyse with unprecedented speed and resolution the function of several different genes simultaneously, during vascular development, homeostasis or associated diseases. Understanding the genetic epistatic interactions that control the differentiation and behaviour of endothelial cells, in different contexts, and with high cellular definition, has the potential to unveil new mechanisms with high biological and therapeutic relevance.

1 481 375 €

Start date: 2015-03-01, End date: 2020-02-29

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

Dysregulation of capillary permeability is a severe problem in critically ill patients, but the mechanisms involved are poorly understood. Further, there are no targeted therapies to stabilize leaky vessels in various common, potentially fatal diseases, such as systemic inflammation and sepsis, which affect millions of people annually. Although a multitude of signals that stimulate opening of endothelial cell-cell junctions leading to permeability have been characterized using cellular and in vivo models, approaches to reverse the harmful process of capillary leakage in disease conditions are yet to be identified. I propose to explore a novel autocrine endothelial permeability regulatory system as a potentially universal mechanism that antagonizes vascular stabilizing ques and sustains vascular leakage in inflammation. My group has identified inflammation-induced mechanisms that switch vascular stabilizing factors into molecules that destabilize vascular barriers, and identified tools to prevent the barrier disruption. Building on these discoveries, my group will use mouse genetics, structural biology and innovative, systematic antibody development coupled with gene editing and gene silencing technology, in order to elucidate mechanisms of vascular barrier breakdown and repair in systemic inflammation. The expected outcomes include insights into endothelial cell signaling and permeability regulation, and preclinical proof-of-concept antibodies to control endothelial activation and vascular leakage in systemic inflammation and sepsis models. Ultimately, the new knowledge and preclinical tools developed in this project may facilitate future development of targeted approaches against vascular leakage.

1 999 770 €

Start date: 2018-05-01, End date: 2023-04-30

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

Atherosclerosis is characterized by chronic inflammation of the arterial wall. Mononuclear cell recruitment is driven by chemokines that can be deposited e.g. by activated platelets on inflamed endothelium. Chemokines require oligomerization and immobilization for efficient function, and recent evidence supports the notion that heterodimer formation between chemokines constitutes a new regulatory principle amplifying specific chemokine activities while suppressing others. Although crucial to inflammatory disease, this has been difficult to prove in vivo, primarily as chemokine heterodimers exist in equilibrium with their homodimer counterparts. We introduce the paradigm that heteromerization of chemokines provides the combinatorial diversity for functional plasticity and fine-tuning, coining this interactome. Given the relevance of chemokine heteromers in vivo, we aim to exploit this in an anti-inflammatory approach to selectively target vascular disease. In a multidisciplinary project, we plan to generate covalently-linked heterodimers to establish their biological significance. Obligate heterodimers of CC and CXC chemokines will be designed using computer-assisted modeling, chemically synthesized and cross-linked, structurally assessed using NMR spectroscopy and crystallography, and subjected to functional characterization in vitro and reconstitution in vivo. Conversely, we will develop cyclic beta-sheet-based peptides binding chemokines to specifically disrupt heteromers and we will generate mice with conditional deletion or knock-in of chemokine mutants with defects in heteromerization or proteoglycan binding to be analyzed in models of atherosclerosis. Peptides will be used for molecular imaging and chemokine heteromers will be quantified in cardiovascular patients.

2 500 000 €

Start date: 2010-04-01, End date: 2016-03-31

The formation of a functional patterned vascular network is essential for development, tissue growth and organ physiology. Several human vascular disorders arise from the mis-patterning of blood vessels, such as arteriovenous malformations, aneurysms and diabetic retinopathy. Although blood flow is recognised as a stimulus for vascular patterning, very little is known about the molecular mechanisms that regulate endothelial cell behaviour in response to flow and promote vascular patterning. Recently, we uncovered that endothelial cells migrate extensively in the immature vascular network, and that endothelial cells polarise against the blood flow direction. Here, we put forward the hypothesis that vascular patterning is dependent on the polarisation and migration of endothelial cells against the flow direction, in a continuous flux of cells going from low-shear stress to high-shear stress regions. We will establish new reporter mouse lines to observe and manipulate endothelial polarity in vivo in order to investigate how polarisation and coordination of endothelial cells movements are orchestrated to generate vascular patterning. We will manipulate cell polarity using mouse models to understand the importance of cell polarisation in vascular patterning. Also, using a unique zebrafish line allowing analysis of endothelial cell polarity, we will perform a screen to identify novel regulators of vascular patterning. Finally, we will explore the hypothesis that defective flow-dependent endothelial polarisation underlies arteriovenous malformations using two genetic models. This integrative approach, based on high-resolution imaging and unique experimental models, will provide a unifying model defining the cellular and molecular principles involved in vascular patterning. Given the physiological relevance of vascular patterning in health and disease, this research plan will set the basis for the development of novel clinical therapies targeting vascular disorders.

1 618 750 €

Start date: 2016-09-01, End date: 2021-08-31

In the bone-enclosed CNS, increased vascular permeability may cause life-threatening tissue swelling, and/or ischemia and inflammation which compromise tissue repair after trauma or stroke. The brain vasculature possesses several unique features collectively named the blood-brain barrier (BBB) in which passive permeability is almost completely abolished and replaced by a complex of specific transport mechanisms. The BBB is necessary to uphold the specific milieu necessary for neuronal function. Whereas breakdown of the BBB is part of many CNS diseases, including stroke, neuroinflammation, trauma and neurodegenerative disorders, its molecular mechanisms and consequences are unclear and debated. Conversely, the intact BBB is a huge obstacle for drug delivery to the brain. Research on the BBB therefore has two seemingly opposing aims: 1) to seal a damaged BBB and protect the brain from toxic blood products, and 2) to open the BBB “on demand” for drug delivery. A major problem in the BBB field has been the lack of in vivo animal models for molecular and functional studies. So far, available in vitro models are not recapitulating the in vivo BBB. Our recent work on mouse models lacking pericytes, a BBB-associated cell type, demonstrates a specific role for pericytes in the development and regulation of the mammalian BBB. These animal models are the first ones showing a general and significant BBB impairment in adulthood, and as such they provide a unique opportunity to address molecular mechanisms of BBB disruption in disease and in drug transport across the BBB. Importantly, the new models and tools that we have developed allow us to search for relevant druggable mechanisms and molecular targets in the BBB. The long-term goals of this proposal are to develop molecular strategies and tools to open and close the BBB “on demand” for drug delivery to the CNS, and to explore the importance and mechanisms of BBB dysfunction in neurodegenerative diseases and stroke.

2 499 427 €

Start date: 2012-08-01, End date: 2017-07-31

The challenge in cell physiology/pathology today is to translate in vitro findings to the living organism. We have developed a unique approach where signal-transduction can be investigated in vivo non-invasively, longitudinally at single cell resolution, using the anterior chamber of the eye as a natural body window for imaging. We will use this approach to understand how the universally important and highly complex signal Ca2+ is regulated in the pancreatic beta-cell, while localized in the vascularized and innervated islet of Langerhans, and how that affects the insulin secretory machinery in vivo. Engrafted islets in the eye take on identical innervation- and vascularization patterns as those in the pancreas and are proficient in regulating glucose homeostasis in the animal. Since the pancreatic islet constitutes a micro-organ, this imaging approach offers a seminal model system to understand Ca2+ signaling in individual cells at the organ level in real life. We will test the hypothesis that the Ca2+-signal has a key role in pancreatic beta-cell function and survival in vivo and that perturbation in the Ca2+-signal serves as a common denominator for beta-cell pathology associated with impaired glucose homeostasis and diabetes. Of special interest is how innervation impacts on Ca2+-dynamics and the integration of autocrine, paracrine and endocrine signals in fine-tuning the Ca2+-signal with regard to beta-cell function and survival. We aim to define key defects in the machinery regulating Ca2+-dynamics in association with the autoimmune reaction, inflammation and obesity eventually resulting in diabetes. Our imaging platform will be applied to clarify in vivo regulation of Ca2+-dynamics in both healthy and diabetic human beta-cells. To define novel drugable targets for treatment of diabetes, it is crucial to identify similarities and differences in the molecular machinery regulating the in vivo Ca2+-signal in the human and in the rodent beta-cell.

2 499 590 €

Start date: 2014-03-01, End date: 2019-02-28

A fundamental challenge of pancreas biology is to understand and manipulate the determinants of beta cell mass. The homeostatic maintenance of adult beta cell mass relies largely on replication of differentiated beta cells, but the triggers and signaling pathways involved remain poorly understood. Here I propose to investigate the physiological and molecular mechanisms that control beta cell replication. First, novel transgenic mouse tools will be used to isolate live replicating beta cells and to examine the genetic program of beta cell replication in vivo. Information gained will provide insights into the molecular biology of cell division in vivo. Additionally, these experiments will address critical unresolved questions in beta cell biology, for example whether duplication involves transient dedifferentiation. Second, genetic and pharmacologic tools will be used to dissect the signaling pathways controlling the entry of beta cells to the cell division cycle, with emphasis on the roles of glucose and insulin, the key physiological input and output of beta cells. The expected outcome of these studies is a detailed molecular understanding of the homeostatic maintenance of beta cell mass, describing how beta cell function is linked to beta cell number in vivo. This may suggest new targets and concepts for pharmacologic intervention, towards the development of regenerative therapy strategies in diabetes. More generally, the experiments will shed light on one of the greatest mysteries of developmental biology, namely how organs achieve and maintain their correct size. A fundamental challenge of pancreas biology is to understand and manipulate the determinants of beta cell mass. The homeostatic maintenance of adult beta cell mass relies largely on replication of differentiated beta cells, but the triggers and signaling pathways involved remain poorly understood. Here I propose to investigate the physiological and molecular mechanisms that control beta cell replication. First, novel transgenic mouse tools will be used to isolate live replicating beta cells and to examine the genetic program of beta cell replication in vivo. Information gained will provide insights into the molecular biology of cell division in vivo. Additionally, these experiments will address critical unresolved questions in beta cell biology, for example whether duplication involves transient dedifferentiation. Second, genetic and pharmacologic tools will be used to dissect the signaling pathways controlling the entry of beta cells to the cell division cycle, with emphasis on the roles of glucose and insulin, the key physiological input and output of beta cells. The expected outcome of these studies is a detailed molecular understanding of the homeostatic maintenance of beta cell mass, describing how beta cell function is linked to beta cell number in vivo. This may suggest new targets and concepts for pharmacologic intervention, towards the development of regenerative therapy strategies in diabetes. More generally, the experiments will shed light on one of the greatest mysteries of developmental biology, namely how organs achieve and maintain their correct size.

1 445 000 €

Start date: 2010-09-01, End date: 2015-08-31

The heart is one of the first and most complex organs formed during human embryogenesis. While its anatomy and physiology have been extensively studied over centuries, the normal development of human heart and dysregulation in disease still remain poorly understood at the molecular/cellular level. Stem cell technologies hold promise for modelling development, analysing disease mechanisms, and developing potential therapies. By combining multidisciplinary approaches centred on human induced pluripotent stem cells (hiPSCs), BIOCARD aims at decoding the cellular and molecular principles of human cardiogenesis and developing advanced inter-chimeric human-pig models of cardiac development and disease. State-of-the-art genetic modification techniques and functional genomics will be used to establish a molecular atlas of cell type intermediates of human cardiogenesis in vitro and unravel how their proliferation, differentiation and lineage choice are regulated in health and disease. This in vitro approach will be complemented by detailed analyses of how distinct hiPSC-derived cardiac progenitor populations commit and contribute to specific cardiac compartments in interspecies chimeric hearts in vivo. Finally, we will capitalize on the novel concept that combinations of different well-defined hiPSC-derived cardiac progenitor pools with timely-matched, native extracellular matrix from embryonic hearts will accomplish for the first time the realization of human heart organoids as 3D culture systems of developing heart structures. Clearly, BIOCARD will open game-changing opportunities for devising novel biomedical applications, such as human heart chamber-specific disease modelling, large-scale drug testing in appropriate human 3D cardiac bio-mimics, and regenerative cell therapies based on functional ventricular-muscle patches and direct cell conversion in vivo.

2 285 625 €

Start date: 2018-09-01, End date: 2023-08-31

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

The gastrointestinal tract is emerging as a key regulator of appetite and metabolism, but studies aimed at identifying the signals involved are faced with daunting neuroanatomical complexity: there are as many as 500 million neurons in the human gut. Drosophila should provide a simple and genetically amenable alternative, but both its autonomic nervous system and the signalling significance of its digestive tract have remained largely unexplored. My research programme will characterize the signals and neurons mediating the interaction between the nervous and digestive systems, and will establish their significance both in the maintenance of metabolic homeostasis and in response to nutritional challenges. To achieve these goals, we will capitalize on a multi-disciplinary approach that combines the genetic manipulation of defined neuronal lineages, a cell-biological approach to the study of enterocyte metabolism, and our recently developed physiological and behavioural readouts. Our work will provide new insights into the signals and mechanisms modulating internal metabolism and food intake: processes which, when deregulated, contribute to increasingly prevalent conditions such as diabetes, metabolic syndrome and obesity. Our recent finding of conserved mechanisms of autonomic control in the fruit fly makes us confident that the signals we identify will be relevant to mammalian systems.

1 499 740 €

Start date: 2013-02-01, End date: 2018-01-31

"Bicuspid aortic valve, a heart valve with only two leaflets instead of three, is the most common congenital heart defect with an estimated prevalence of about 1-2%. The heart defect often remains asymptomatic but in at least 10% of the bicuspid aortic valve patients, an ascending aortic aneurysm develops as well. If not detected in a timely fashion, this can lead to an aortic aneurysm dissection with a high mortality. In view of the prevalent nature of this heart defect, this implies an important health care problem. Historically, it was always hypothesized that abnormal blood flow across the bicuspid aortic valve led to aneurysm formation. However in recent years, the importance of a genetic contribution has been suggested based on the high heritability and it is currently believed that the same genetic factors predispose to the developmental valve defect and the aortic aneurysm formation. The inheritance pattern is most consistent with an autosomal dominant disorder with variable penetrance and expressivity. Until now, the latter have significantly hampered the causal gene identification but the era of next generation sequencing is now offering unprecedented opportunities for a major breakthrough in this area. Through detailed signalling pathway analysis, miRNA profiling and next generation sequencing, this project will contribute significantly to resolving the genetic causes of bicuspid related aortopathy, provide critical knowledge on the pathogenesis of aortic aneurysmal disease and deliver a mouse model for future therapeutical trials."

1 497 895 €

Start date: 2013-05-01, End date: 2018-04-30

Tissue homeostasis requires coordinated barrier function in blood and lymphatic vessels. Opening of junctions between endothelial cells (ECs) lining blood vessels leads to tissue fluid accumulation that is drained by lymphatic vessels. A pathological increase in blood vessel permeability or lack or malfunction of lymphatic vessels leads to edema and associated defects in macromolecule and immune cell clearance. Unbalanced barrier function between blood and lymphatic vessels contributes to neurodegeneration, chronic inflammation, and cardiovascular disease. In this proposal, we seek to gain mechanistic understanding into coordination of barrier function between blood and lymphatic vessels, how this process is altered in disease models and how it can be manipulated for therapeutic purposes. We will focus on two critical barriers with diametrically opposing functions, the blood-brain barrier (BBB) and the lymphatic capillary barrier (LCB). ECs of the BBB form very tight junctions that restrict paracellular access to the brain. In contrast, open junctions of the LCB ensure uptake of extravasated fluid, macromolecules and immune cells, as well as lipid in the gut. We have identified novel effectors of BBB and LCB junctions and will determine their role in adult homeostasis and in disease models. Mouse genetic gain and loss of function approaches in combination with histological, ultrastructural, functional and molecular analysis will determine mechanisms underlying formation of tissue specific EC barriers. Deliverables include in vivo validated targets that could be used for i) opening the BBB on demand for drug delivery into the brain, and ii) to lower plasma lipid uptake via interfering with the LCB, with implications for prevention of obesity, cardiovascular disease and inflammation. These pioneering studies promise to open up new opportunities for research and treatment of neurovascular and cardiovascular disease.

2 499 969 €

Start date: 2019-07-01, End date: 2024-06-30

Gastric bypass surgery results in massive weight loss and diabetes remission. The effect is superior to intensive medical treatment, showing that there are mechanisms within the body that can cure diabetes and obesity. Revealing the nature of these mechanisms could lead to new, cost-efficient, similarly effective, non-invasive treatments of these conditions. The hypothesis is that hyper-secretion of a number of gut hormones mediates the effect of surgery, as indicated by a series of our recent studies, demonstrating that hypersecretion of GLP-1, a hormone discovered in my laboratory and basis for the antidiabetic medication of millions of patients, is essential for the improved insulin secretion and glucose tolerance. But what are the mechanisms behind the up to 30-fold elevations in secretion of these hormones following surgery? Constantly with a translational scope, all elements involved in these responses will be addressed in this project, from detailed analysis of food items responsible for hormone secretion, to identification of the responsible regions of the gut, and to the molecular mechanisms leading to hypersecretion. Novel approaches for studies of human gut hormone secreting cells, including specific expression analysis, are combined with our advanced and unique isolated perfused gut preparations, the only tool that can provide physiologically relevant results with a translational potential regarding regulation of hormone secretion in the gut. This will lead to further groundbreaking experimental attempts to mimic and engage the identified mechanisms, creating similar hypersecretion and obtaining similar improvements as the operations in patients with obesity and diabetes. Based on our profound knowledge of gut hormone biology accumulated through decades of intensive and successful research and our successful elucidation of the antidiabetic actions of gastric bypass surgery, we are in a unique position to reach this ambitious goal.

2 500 000 €

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

"Heart failure is a serious clinical disorder that represents the primary cause of hospitalization and death in Europe and the United States. There is a dire need for new paradigms and therapeutic approaches for treatment of this devastating disease. The heart responds to mechanical load and various extracellular stimuli by hypertrophic growth and sustained pathological hypertrophy is a major clinical predictor of heart failure. A variety of stress-responsive signaling pathways promote cardiac hypertrophy, but the precise mechanisms that link these pathways to cardiac disease are only beginning to be unveiled. Signal transduction is traditionally concentrated on the protein coding part of the genome, but it is now appreciated that the protein coding part of the genome only constitutes 1.5% of the genome. RNA based mechanisms may provide a more complete understanding of the fundamentals of cellular signaling. As a proof-of-principle, we focus on a principal hypertrophic signaling cascade, cardiac calcineurin/NFAT signaling. Here we will establish that microRNAs are intimately interwoven with this signaling cascade, influence signaling strength by unexpected upstream mechanisms. Secondly, we will firmly establish that microRNA target genes critically contribute to genesis of heart failure. Third, the surprising stability of circulating microRNAs has opened the possibility to develop the next generation of biomarkers and provide unexpected mechanisms how genetic information is transported between cells in multicellular organs and fascilitate inter-cellular communication. Finally, microRNA-based therapeutic silencing is remarkably powerful and offers opportunities to specifically intervene in pathological signaling as the next generation heart failure therapeutics. CALMIRS aims to mine the wealth of these RNA mechanisms to enable the development of next generation RNA based signal transduction biology, with surprising new diagnostic and therapeutic opportunities."

1 499 528 €

Start date: 2013-02-01, End date: 2018-01-31

Even at their earliest stages, human cancers are more than just cells with malignant potential. Cells and extracellular matrix components that normally support and protect the body are coerced into a tumour microenvironment that is central to disease progression. My hypothesis is that recent advances in tissue engineering, biomechanics and stem cell biology make it possible to engineer, for the first time, a complex 3D human tumour microenvironment in which individual cell lineages of malignant, haemopoietic and mesenchymal origin will communicate, evolve and grow in vitro. The ultimate aim is to build this cancerous tissue with autologous cells: there is an urgent need for models in which we can study the interaction of human immune cells with malignant cells from the same individual in an appropriate 3D biomechanical microenvironment. To achieve the objectives of the CANBUILD project, I have assembled a multi-disciplinary team of collaborators with international standing in tumour microenvironment research, cancer treatment, tissue engineering, mechanobiology, stem cell research and 3D computer-assisted imaging. The goal is to recreate the microenvironment of high-grade serous ovarian cancer metastases in the omentum. This is a major clinical problem, my lab has extensive knowledge of this microenvironment and we have already established simple 3D models of these metastases. The research plan involves: Deconstruction of this specific tumour microenvironment Construction of artificial scaffold, optimising growth of cell lineages, assembly of the model Comparison to fresh tissue Investigating the role of individual cell lineages Testing therapies that target the tumour microenvironment My vision is that this project will revolutionise the practice of human malignant cell research, replacing misleading systems based on cancer cell monoculture on plastic surfaces and allowing us to better test new treatments that target the human tumour microenvironment.

2 431 035 €

Start date: 2013-06-01, End date: 2018-05-31

Introduction: Current anti-cancer treatments are often inefficient, while many patients initially benefit from anti-cancer drugs eventually experience relapse of resistant tumors throughout the body. Current clinical strategies mainly aim at inducing tumor cell death, but this induction may have unintentional and unwanted side effects on surviving tumor cells. Preliminary data: We show that after chemotherapy-induced initial regression, PyMT mammary tumors reappear. During regression, we observe an increased number of cells that have undergone epithelial-mesenchymal transition (EMT) and become migratory. We show that migration can be induced upon uptake of extracellular vesicles (e.g. apoptotic bodies). Our findings suggest that EMT is induced upon chemotherapy, through e.g. EV uptake, potentially leading to migration and growth of surviving cells. Hypothesis and main aim: Based on preliminary data, we hypothesize that tumor cell death induces migration and growth of the surviving tumor cells. We aim to identify the key cell types and mechanisms that mediate this effect, and establish whether interference with these cells and mechanisms can reduce recurrence of tumors after chemotherapy. Approach: We have developed unique intravital imaging tools and genetically engineered fluorescent mice to visualize and characterize if and how dying tumor cells can affect surrounding surviving tumor and stromal cells. We will test whether dying tumor cells can influence the growth, migration, dissemination and metastasis of surviving tumor cells directly or indirectly through stromal cells. We will identify potential targets to block the influence of the dying tumor cells, and test whether this blockade inhibits the unintended side-effects of tumor cell death. Conclusion: With the studies proposed in this grant, we will gain fundamental insights on how induction of tumor cell death, the universal aim of therapy, could play a role in growth and spread of surviving tumor cells.

2 000 000 €

Start date: 2015-09-01, End date: 2020-08-31

The actual view of cellular transformation and cancer progression supports the notion that cancer cells must undergo metabolic reprogramming in order to survive in a hostile environment. This field has experienced a renaissance in recent years, with the discovery of cancer genes regulating metabolic homeostasis, in turn being accepted as an emergent hallmark of cancer. Prostate cancer presents one of the highest incidences in men mostly in developed societies and exhibits a significant association with lifestyle environmental factors. Prostate cancer recurrence is thought to rely on a subpopulation of cancer cells with low-androgen requirements, high self-renewal potential and multidrug resistance, defined as cancer-initiating cells. However, whether this cancer cell fraction presents genuine metabolic properties that can be therapeutically relevant remains undefined. In CancerMetab, we aim to understand the potential benefit of monitoring and manipulating metabolism for prostate cancer prevention, detection and therapy. My group will carry out a multidisciplinary strategy, comprising cellular systems, genetic mouse models of prostate cancer, human epidemiological and clinical studies and bioinformatic analysis. The singularity of this proposal stems from the approach to the three key aspects that we propose to study. For prostate cancer prevention, we will use our faithful mouse model of prostate cancer to shed light on the contribution of obesity to prostate cancer. For prostate cancer detection, we will overcome the consistency issues of previously reported metabolic biomarkers by adding robustness to the human studies with mouse data integration. For prostate cancer therapy, we will focus on a cell population for which the metabolic requirements and the potential of targeting them for therapy have been overlooked to date, that is the prostate cancer-initiating cell compartment.

1 498 686 €

Start date: 2013-11-01, End date: 2019-10-31

Recent ground-breaking studies by my team and others demonstrated that latent heart regeneration machinery can be awakened even in adult mammals. My lab’s main contribution is the identification of two, apparently different, molecular mechanisms for augmenting cardiac regeneration in adult mice. The first requires transient activation of ErbB2 signalling in cardiomyocytes and the second involves extra cellular matrix-driven signalling by the proteoglycan agrin. Impressively, both mechanisms promote a major regenerative response that, in turn, enhances cardiac repair. In CardHeal we will use the two powerful regenerative models to obtain a holistic view of cardiac regeneration and repair mechanisms in mammals (mice and pigs). In Aim 1, we will explore the molecular mechanisms underlying our discovery that transient activation of ErbB2 in adult cardiomyocytes results in massive cardiomyocyte dedifferentiation and proliferation followed by new vessels formation, scar resolution and functional cardiac repair. Specific objectives focus on ErbB2-Yap/Hippo signalling during cardiac regeneration; ErbB2 activation in a chronic heart failure model; ErbB2-induced regenerative EMT-like process; and cardiomyocyte re-differentiation. In Aim 2, we will investigate the therapeutic effects of agrin, whose administration into injured hearts of mice and pigs elicits a significant regenerative response. Specific objectives are matrix-related cardiac regenerative cues, modulation of the immune response, angiogenesis, matrix remodeling, and developing a preclinical, large animal model to study agrin efficacy for cardiac repair. Interrogating the differences and similarities between our two regenerative models should give us a detailed roadmap for cardiac regenerative medicine by providing deeper knowledge of the regenerative process in the heart and pointing to novel targets for cardiac repair in human patients.

2 268 750 €

Start date: 2018-06-01, End date: 2023-05-31