ERC FUNDED PROJECTS

Brain and spinal cord diseases affect 38% of the European population and cost over 800 billion € annually; representing by far the largest health challenge. ALS is a prevalent neurological disease caused by motor neuron death with an invariably fatal outcome. I contributed to ALS research with the groundbreaking discovery of TDP-43 mutations, functionally characterized these mutations in the first vertebrate model and demonstrated a genetic interaction with another major ALS gene FUS. Emerging evidence indicates that four major causative factors in ALS, C9orf72, TDP-43, FUS & SQSTM1, genetically interact and could function in common cellular mechanisms. Here, I will develop zebrafish transgenic lines for all four genes, using state of the art genomic editing tools to combine simultaneous gene knockout and expression of the mutant alleles. Using these innovative disease models I will study the functional interactions amongst these four genes and their converging effect on key ALS pathogenic mechanisms: autophagy degradation, stress granule formation and RNA regulation. These studies will permit to pinpoint the molecular cascades that underlie ALS-related neurodegeneration. We will further expand the current ALS network by proposing and validating novel genetic interactors, which will be further screened for disease-causing variants and as pathological markers in patient samples. The power of zebrafish as a vertebrate model amenable to high-content phenotype-based screens will enable discovery of bioactive compounds that are neuroprotective in multiple animal models of disease. This project will increase the fundamental understanding of the relevance of C9orf72, TDP-43, FUS and SQSTM1 by developing animal models to characterize common pathophysiological mechanisms. Furthermore, I will uncover novel genetic, disease-related and pharmacological modifiers to extend the ALS network that will facilitate development of therapeutic strategies for neurodegenerative disorders

2 000 000 €

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

"The deregulation of transcription is an important driver of leukemia development. Typically, transcription in leukemia cells is altered by the ectopic expression of transcription factors, by modulation of signaling pathways or by epigenetic changes. In addition to these factors that affect the production of RNAs, also changes in the processing of RNA (its splicing, transport and decay) may contribute to determine steady-state RNA levels in leukemia cells. Indeed, acquired mutations in various genes encoding RNA splice factors have recently been identified in myeloid leukemias and in chronic lymphocytic leukemia. In our study of T-cell acute lymphoblastic leukemia (T-ALL), we have identified mutations in RNA decay factors, including mutations in CNOT3, a protein believed to function in deadenylation of mRNA. It remains, however, unclear how mutations in RNA processing can contribute to the development of leukemia. In this project, we aim to further characterize the mechanisms of RNA regulation in T-cell acute lymphoblastic leukemia (T-ALL) to obtain insight in the interplay between RNA generation and RNA decay and its role in leukemia development. We will study RNA decay in human T-ALL cells and mouse models of T-ALL, with the aim to identify the molecular consequences that contribute to leukemia development. We will use new technologies such as RNA-sequencing in combination with bromouridine labeling of RNA to measure RNA transcription and decay rates in a transcriptome wide manner allowing unbiased discoveries. These studies will be complemented with screens in Drosophila melanogaster using an established eye cancer model, previously also successfully used for the studies of T-ALL oncogenes. This study will contribute to our understanding of the pathogenesis of T-ALL and may identify new targets for therapy of this leukemia. In addition, our study will provide a better understanding of how RNA processing is implicated in cancer development in general."

1 998 300 €

Start date: 2014-05-01, End date: 2019-04-30

Brain information processing is commonly thought to be a neuronal performance. However recent data point to a key role of astrocytes in brain development, activity and pathology. Indeed astrocytes are now viewed as crucial elements of the brain circuitry that control synapse formation, maturation, activity and elimination. How do astrocytes exert such control is matter of intense research, as they are now known to participate in critical developmental periods as well as in psychiatric disorders involving synapse alterations. Thus unraveling how astrocytes control synaptic circuit formation and maturation is crucial, not only for our understanding of brain development, but also for identifying novel therapeutic targets. We recently found that connexin 30 (Cx30), an astroglial gap junction subunit expressed postnatally, tunes synaptic activity via an unprecedented non-channel function setting the proximity of glial processes to synaptic clefts, essential for synaptic glutamate clearance efficacy. Our work not only reveals Cx30 as a key determinant of glial synapse coverage, but also extends the classical model of neuroglial interactions in which astrocytes are generally considered as extrasynaptic elements indirectly regulating neurotransmission. Yet the molecular mechanisms involved in such control, its dynamic regulation by activity and impact in a native developmental context are unknown. We will now address these important questions, focusing on the involvement of this novel astroglial function in wiring developing synaptic circuits. Thus using a multidisciplinary approach we will investigate: 1) the molecular and cellular mechanisms underlying Cx30 regulation of synaptic function 2) the activity-dependent dynamics of Cx30 function at synapses 3) a role for Cx30 in wiring synaptic circuits during critical developmental periods This ambitious project will provide essential knowledge on the molecular mechanisms underlying astroglial control of synaptic circuits.

2 000 000 €

Start date: 2016-10-01, End date: 2021-09-30

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