Team leader : Guillaume van Niel
Team member : Alexandre Androuin | Anaïs Bécot | Mickael Couty | Vincenzo Verdi | Frédérik Verweij
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Les travaux de notre équipe cherchent à mieux comprendre les mécanismes régulant la biogenèse et les fonctions de la voie endosomale dans différents types cellulaires spécialisés, in vitro et in vivo. En fonction de leur environnement et des stimuli reçus, les cellules peuvent adapter leur système endosomal pour dégrader le contenu des endosomes multivésiculaires dans les lysosomes ou pour sécréter dans le milieu extracellulaire leurs vésicules intraluminales sous forme d’exosomes. A travers nos études, nous cherchons à identifier différents mécanismes moléculaires qui régulent ces adaptations fonctionnelles et à développer différents outils pour suivre la dynamique endosomale in vitro et in vivo. Ces recherches nous permettrons de mieux comprendre le rôle de la dynamique endosomale dans différentes neuropathies et en particulier la Maladie d'Alzheimer et le développement du Gliobastome. |
At the Institute of Psychiatry and Neurosciences of Paris, we use a multi-scale approach, based on the complementarity of cellular models and a model organism, the zebrafish, to better understand the role of the endosomal pathway in various neuropathies.
Within the cell, the endosomal pathway comprises a series of interconnected compartments whose primary functions are to degrade, sequester, recycle or secrete components of the plasma membrane and previously internalized extracellular elements. This pathway is involved in various pathological processes affecting the nervous system such as amyloid homeostasis and tumour migration. We are particularly interested in the degradation and secretion functions of the endosomal pathway, focusing on the multivesicular endosomes that are at the crossroads of these two functions. By merging with lysosomes, multivesicular endosomes allow catabolism and recycling of their contents and participate in cell homeostasis. By fusing with the plasma membrane, they secrete their contents into the extracellular medium, in particular vesicles called exosomes. These exosomes act as vectors of clearance and intercellular communication in all organisms. They are involved in the development of many pathologies but could also be used in clinics as biomarkers or therapeutic nano-vehicles.
The projects of our laboratory have three objectives:
The first objective is to deepen and generalize our fundamental knowledge of the intracellular mechanisms regulating the biogenesis and functions of multivesicular endosomes and exosomes. In particular, we focus on the role of membrane contact sites in lysosomal degradation and exosomal secretion processes.
The second objective is to evaluate, in parallel, the relevance of these intracellular mechanisms in nervous system cells and in an in vivo model, the zebrafish. This multi-scale approach, based on advanced imaging methods such as correlative microscopy or subcellular videomicroscopy, allows us to analyze the endosomal dynamics and biology of exosomes on live and in vivo neuronal cells.
The third objective is to combine the knowledge and tools developed in the first two objectives in order to evaluate their relevance in the development but also the treatment of different neuropathies, such as Alzheimer's disease and glioblastoma.
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Figure : Schematic model of the role of endosomal dynamics
Our studies focus on the role of the endosomal pathway in the development of neuropathies such as Alzheimer's disease and glioblastoma. In this context, we are seeking to better understand the mechanisms that regulate the degenerative (via lysosomes) and secretory (via exosomes) functions in neuronal cells. To do this we rely on advanced imaging techniques and the development of new molecular tools in a model organism, zebrafish and cell cultures. |
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Guillaume Van Niel Since 1998, Guillaume van Niel has investigated exosomes and their compartment of origin, multivesicular bodies. During his Ph.D at the Necker institute (Paris, France), he reported and investigated the secretion and the function of exosomes secreted by intestinal epithelial cells. In 2003 at the Utrecht medial center (Utrecht, the Netherlands) he demonstrated ubiquitination of MHC II molecules, a key post-translational modification for sorting to multivesicular bodies in dendritic cells. In 2005 he joined the Curie Institute (Paris, France) and obtained a CNRS permanent position in this team in 2008 to investigate the biogenesis of multivesicular bodies in pigment cells. He notably reported the role of intraluminal vesicles in the generation of physiological amyloid fibrils. Since 2017 he is team leader at the Intitute of Psychiatry and Neurosciences of Paris (Paris, France) developing new tools to visualize exosomes, notably in vivo, and to understand the role of endosomal dynamic between degradation and secretion in amyloid associated pathologies. He has a strong expertise in the cell biology of exosomes and uses extensively different techniques of imaging among which electron microscopy.
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Frederik Verweij Frederik Verweij started his PhD in 2009, studying the sorting of a viral oncoprotein in exosomes at the Free University Medical Center (VUmc) in Amsterdam (The Netherlands) under supervision of Drs Michiel D. Pegtel and Jaap Middeldorp. This protein, LMP1, is encoded by Epstein Barr virus (EBV), a virus that hijacks human B-cell development to establish a latent infection in approximately 90% of the world population. LMP1 is a viral mimic of CD40 and one of the viral key-proteins that drives EBV infected B-cells through the B-cell germinal center reaction to become a memory B-cell, He demonstrated that mechanistically, the sorting of LMP1 depends on its association with CD63, one of the tetraspanins enriched on late-endosomal intraluminal vesicles (ILVs), the intracellular precursors of exosomes. Functionally, the sorting of this protein restrains the constitutively active NF-kB signaling of this protein, that would otherwise lead to uncontrolled NF-kB signaling, which is associated with lymphomagenesis in in vivo mouse models. During his PhD, he also pioneered the use of CD63-pHluorin to visualize exosome secretion from living cells in vitro. This novel approach circumventes cumbersome isolation procedures that had prevented dynamic insight into the exosome secretion process till then. This work also laid the basis for his current work, where he is studying exosome secretion and trafficking in vivo during development and cancer, using zebrafish embryos as a model organism.
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Anaïs Bécot Anaïs Bécot completed her PhD (2016-2019) at the Institute of Molecular and Cellular Pharmacology (IPMC) in Sophia-Antipolis (France), under the supervision of Dr. Inger Lauritzen and Dr. Frédéric Checler who are interested in the role of APP metabolites in the Alzheimer's disease pathological mechanisms. Anaïs focused on the study of the APP-CTFb fragment, whose intraneuronal accumulation is associated with endosomal-lysosomal-autophagic defects appearing early in Alzheimer's patients. In a first project, she tested the efficacy of the activation of the lysosomal-autophagic system in in vitro and in vivo models of Alzheimer's disease, with the aim of reducing the levels of APP-CTFb and associated pathological phenotypes. In a second project, she investigated the role of APP-CTFb in the spreading of the disease in the brain by studying a type of extracellular vesicle, the exosomes. This work revealed the enrichment of APP-CTFb oligomeric forms in exosomes released by Alzheimer's model cells, as well as a link between oligomerization and g-secretase activity. In May 2020, she joined the team of Dr. Guillaume van Niel where she is studying the mechanisms involved in the balance between endolysosomal degradation and exosomal secretion. Her project focuses in particular on the effect of apolipoprotein E particles on endolysosome trafficking and exosome secretion by modulating the formation of membrane contact sites.
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Vincenzo Verdi Vincenzo Verdi graduated in 2015 in Medical Biotechnologies and Molecular Medicine at University of Palermo (Italy). His research experience started in 2014 at the Department of Biopathology and Medical Biotechnologies in Palermo in Prof. Riccardo Alessandro’s team, working on the autocrine role of extracellular vesicles (EVs) in Chronic Myeloid Leukemia cell lines. After, Vincenzo got a 2 years-internship at the Department of Biomedicine and Clinical Neurosciences (University of Palermo) in Prof. Natale Belluardo’s team, carrying on studies on the transactivation of FGFR1 by Muscarinic Acetylcholine Receptors in hippocampal neurons in vitro and the effects of Oxotremorine as axiolitic/ antidepressant in vivo in chronic restraint-stress (CRS) mice and rats models . In 2016 he obtained a PhD position in "Neurosciences" at Scuola Normale Superiore in Pisa, where he joined the “Intrabody Lab” of Prof. Antonino Cattaneo working on "in cell- epitope mapping" in S. cerevisiae of ScFV intrabodies selected against Neuroligin-1/2. In July 2018 he quitted this position and came back to the EVs’ field joining back the group of Prof. Riccardo Alessandro in Univ. of Palermo as research volunteer, performing studies on Ankylosing Spondilytis patients sera- derived EVs in monocytes differentiation. From January 2020 Vincenzo Verdi is a member of proEVLifeCycle Consortium as Marie Skłodowska-Curie ITN PhD Fellow and part of Dr. Guillaume van Niel’s team. He is currently developing molecular tools to redirect and manipulate the fate of Prostate Cancer- derived EVs in vivo, studying their role in the recipient cells and exploiting Zebrafish (Danio rerio) as a valid model to investigate tumor exosomal dynamics in real- time. LinkedIn profile link : https://it.linkedin.com/in/vincenzo-verdi-a18b66106
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Mickaël Couty
Mickaël Couty obtained his Master's degree in Health Biology at the University of Paris-Est Créteil (UPEC, France) where he studied tissue, cell and gene biotherapies. During his Master internship he has worked on the resistance mechanisms of urogenital cancers and on the mechanisms of cell death of prostate tumors in response to a targeted therapy combining a hormone with Dermaseptin B2 (DRS-B2)and a cationic antimicrobial peptide derived from biodiversity with anti-tumor and anti-proliferative activity. After graduating in 2019, he joined Dr. Chantal Boulanger's team at the Paris Cardiovascular Research Center (PARCC, Paris, France) as an engineer under the supervision of Dr. Olivier Blanc-Brude. In the context of sickle cell disease, he studied the expression of a family of proteins in peripheral blood cells and in extracellular vesicles released into the blood. Finally, he joined in July 2020 the Institute of Psychiatry and Neurosciences of Paris (Paris, France) where he studies in vivo trafficking of exosomes during development of glioblastoma in the zebrafish model.
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Below you can download the main publications or abstracts and the FRm article
Live Tracking of Inter-organ Communication by Endogenous Exosomes In Vivo
PIKfyve complex regulates early melanosome homeostasis required for physiological amyloid formation
Quantifying exosome secretion from single cells reveals a modulatory role for GPCR signaling
Shedding light on the cell biology of extracellular vesicles
PIKfyve activity regulates reformation of terminal storage lysosomes from endolysosomes.pdf
Vesicles under surveillance
Schematic model of the role of endosomal dynamic regulated by membrane contact site (MCS) in the metabolism of the amyloid peptide Abeta.
Workshop in Paris on March 19 and 20, 2020 on « imaging of extracellular vesicles (EVs) in vivo »
France Alzheimer - organization of a meeting in your laboratory
NeuroFrance2017 Congress and symposium "Neuronal intracellular trafficking in health and diseases"
The EMBL race: "Extracellular Vesicles: From Biology to Biomedical Applications"
Useful links to our partners
Below other publications
Tubular clathrinAP-2 lattices pinch collagen fibers to support 3D cell migration..pdf
Study of Exosomes Shed New Light on Physiology of Amyloidogenesis.
BACE2 processes PMEL to form the melanosome amyloid matrix in pigment cells
Apolipoprotein E Regulates Amyloid Formation within Endosomes of Pigment Cells
Restricted Location of PSEN2/γ-Secretase Determines Substrate Specificity and Generates an Intracellular Aβ Pool.
