Pr. Amorim is the head of the 'Cell Biology of Viral Infection' lab with international expertise of how viruses (e.g. Influenza Virus) exploit the membrane dynamics/ trafficking of the host cell to establish their infectious cycle. Pr. Amorim lab: https://gulbenkian.pt/ciencia/research-groups/mjamorim/

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Viruses rely on being able to concentrate selected material spatiotemporally. In recent years, cell compartmentalization has undergone a paradigm shift. It became clear that material concentrates in specific locations without the need of a lipid barrier. The resultant membraneless compartments are supramolecular assemblies of multivalent proteins and nucleic acids with defined physical properties. Hence, assembly of membranelles organelles offers ideal solutions to organize reactions favouring viral infections. We found that during influenza A virus infection, progeny RNA, in the form of viral ribonucleoproteins (vRNPs), are concentrated in liquid organelles.  Using correlative light and electron microscopy we found that RNPs clustered in structures devoid of delimiting membranes. Using fluorescence recovery after photobleaching we demonstrated that these structures are highly dynamic, and exchange material fast. Life cell tracking of RNPs in productive infections provided the deformative character of viral inclusions, their ability to adapt to several stimuli, the development close to the Endoplasmic Reticulum Exit Sites, and dependency on continuous ER-Golgi vesicular cycling. We propose that viral inclusions constitute dedicated sites for the assembly of influenza A virus genomes, constituted of a complex of eight different vRNPs.

Histone marks have long been suggested to play a role in the regulation of alternative splicing. From such studies, the impact of chromatin in splicing seemed limited, affecting just a small number of exons, and in a modulatory way by just fine-tuning the final splicing outcome. By combining genome-wide transcriptomics and epigenomics machine learning analyses, we have found that chromatin modifications can differentially mark a third of all the alternatively spliced cassette exons expressed in human embryonic stem cells in a combinatorial and position-dependent way, creating what we called Splicing-Associated Chromatin Signatures (SACS). These SACS coordinate the splicing of functionally related genes sharing common RNA binding motifs to an extent that changes in splicing between human cell types correlate with changes in the enrichment of these SACS. Even more, a highly localized change in a single histone mark right at the exon of interest, using CRISPR epigenetic editing tools, is sufficient to induce a change in splicing that can recapitulate the epithelial-to-mesenchymal transition. Taken together, we have evidence of the dynamic role of histone marks in driving the alternative splicing of subset of genes with specific functional and/or regulatory characteristics that could be reverted in a therapeutic context, like for inhibiting EMT-dependent cancer metastasis.

Protein aggregation is a hallmark of many neurodegenerative diseases, including Huntington’s, Parkinson’s and amyotrophic lateral sclerosis. However, the mechanisms linking aggregation to neurotoxicity remain poorly understood, partly because only limited information is available on the native structure of protein aggregates inside cells. We address this pressing issue utilizing the latest developments in cryo-electron tomography (cryo-ET). We prepare thin lamellas of vitrified cells containing protein aggregates using cryo-focused ion beam, and subsequently image them in three dimensions by cryo-ET. This allows us to analyse aggregate structure within pristinely preserved cellular environments and at molecular resolution [1, 2]. Here, I will discuss how our latest results shed new light into the cellular mechanisms of neurodegeneration.

References

[1] Bäuerlein et al. and Fernández-Busnadiego, Cell (2017) 171 (1), 179-187 (link)
[2] Guo et al. and Fernández-Busnadiego, Cell (2018) 172 (4), 696-705 (link)

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Follicular Helper T cells, Cytotoxic T cells (CTL) and Natural Killer (NK) cells are effectors of the immune system that play important roles in defense against viral infection and cancer.   In this talk I will present four vignettes related to biophysical exploration of effector immunological synapses with relevance to infection or cancer.

Early studies of the immunological synapse revealed a canonical architecture with a striking accumulation of T cell receptor (TCR) in the center driven by actin cytoskeleton and endosomal sorting complexes required for transport (ESCRT). The ESCRT machinery can mediate in situ conversion of TCR microclusters into extracellular vesicles we refer to as synaptic ectosomes. We have shown that one function of synaptic ectosomes is the provision of highly active CD40 ligand clusters, which is a key effector molecule of helper T cells.  I will provide an update on in vivo evidence for synaptic ectosome function.

The second topic relates to the role of the adhesion molecule CD2- which mediates “liquid” adhesions. I will describe how CD2, the receptor for CD58 on T cells, contributes to signal amplification that CD2 expression is often low in “exhausted” CD8 tumor infiltrating lymphocytes in several types of cancer, although the regulation of CD2 seems to be distinct from other exhaustion associated receptors like PD1, with which CD2 is highly miscible.

The third topic is the role of Plasmodium falciparum RIFINs to mimic natural inhibitory ligands for cytotoxic effector cells.  Red blood cells have long been known to express CD58, leading the historically important erythrocyte rosetting test for T cells.  The importance of erythrocytes as hosts for Plasmodium falciparum may provide a rationale for retention of T/NK adhesion molecules on the terminally differentiation, enucleated cells.

The fourth topic is the new discovery of cytotoxic bombs deployed by CTL and NK cells against targets.  CTL and NK cells assemble cytotoxic proteins into supramolecular attack particles (SMAPs) with a core of perforin and granzymes and a shell of thrombospondin-1.  I will introduce what we know about these novel entities.  We also show that CD2-CD58 interaction promotes the release of SMAPs into the synapse.

In summary, the biophysical analysis of immunological synapses with supported lipid bilayers continues to generate insights into T cell effector mechanisms.

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Les objectifs de ce cours sont de fournir un aperçu des mécanismes épigénétiques et de leurs liens avec la chromatine. Les différentes fonctions du noyau impliquant le génome et son organisation seront discutées en insistant sur les limites technologiques et les nouvelles approches expérimentales développées. Les liens entre la perte des fonctions du noyau et le développement de pathologies humaines seront présentés.

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This workshop aime to present the ways in which the teams of these 2 LabEx have leveraged their research developments and innovations into commercial realities and/or enterprises and to promote discussions on the process, benefits and pitfalls of technology transfer in fundamental and applied research.

This event will be comprised of:

5 SUCCESS STORIES: Short talks outlining the diverse paths taken for tech transfer-related projects

2 ROUND TABLES: How to develop research into industrial innovations? It will cover the importance of intellectual property, relations with private companies, the pathway to a start-up creation…

Séminaire proposé par shauna katz

•       Cedric BLOUIN (Researcher, Institut Curie)

•       Stéphanie DESCROIX (Team leader, Institut Curie & Co-founder Inorevia)

•       Mohamed EL BEHEIRY (CTO & CPO, Avatar Medical)

•       Amin M’BARKI (CEO, Hummink)

•       Vincent PIEPIORA (Founder & President, Energo)

•       Karla BALAA (Deputy Director - Innovation & Entrepreneurship, PSL Valorisation)

•       Amel BENDALI (COO & Co-Founder, Inorevia)

•       Antoine DREVELLE (CEO, Kapsera)

•       Andrew GRIFFITHS (Prof. ESPCI - PSL & Founder HiFiBiO amongst others)

•       Robert MARINO (Director, Deeptech Founders & CEO, Qubit Pharmaceuticals)

•       Alessandro SIRIA (ERC PoC awardee 2020 project “NanoPrint”, ENS - PSL)

•       Jérémie WEBER (Head of Licensing & Industrial Partnerships, Department de Valorisation et Partneriats Industriels Institut Curie)

Glioblastoma (GBM) is one of the deadliest types of human cancer. Despite a very aggressive treatment regime – including resection of the tumor, radiation and chemotherapy – its estimated recurrence rate is more than 90%. Recurrence is mostly caused by the regrowth of highly invasive cells spreading from the tumor bulk, which are not removed by resection. To develop an effective therapeutic approach, we need to better understand the underlying molecular mechanism of radiation resistance and tumor spreading in GBM.

Radioresistance in GBM is attributed to glioma stem cells (GSCs), a fraction of perivascular, self-renewing, multipotent and tumor-initiating cells. Growing evidence highlights the perivascular space as a niche for GSC survival, resistance to therapy, progression and dissemination. The unknown factor is the dynamics of GSCs, how they end up in the vascular niche and how this impacts on their resistance to therapy.

We demonstrated that both chemoradiation and perivascular niche induce GBM reprogramming towards a quiescent astrocytic-like subpopulation of GSCs. A better survival, G2M arrest and faster DNA-damage repair make this GBM state more resistant to therapy. Moreover, these AC-like resistant GBM cells are more vessel co-opting allowing homing to the perivascular niche, that induces further resistance to therapy.

We are now focused on elucidating the molecular mechanisms of this vicious positive loop of reprogramming and vessel co-option in other to eradicating these resistant and recurrent GSCs.

While the signals regulating apoptosis during development are rather well known, what regulates the precise spatio-temporal distribution of cell death and the adjustment of cell elimination to local perturbations is not well understood. Similarly, how cells eventually engage in apoptosis and how the removal of cells from epithelial layer is orchestrated through cell extrusion remained poorly understood, especially in vivo. In this seminar, I will present two recent studies illustrating our attempt to dissect these two layers of regulation.

I will first illustrate how tissue can adapt to high rates of cell elimination by modulating the spatiotemporal distribution of cell death through local feedbacks.  Using the Drosophila pupal notum (a single layer epithelium), optogenetics control of caspases, statistical analysis of cell elimination with live sensor of signaling pathways, we showed that local pulses of EGFR/ERK triggered by cell death inhibit transiently caspase activation in neigbouring cells, hence preventing the concomitant elimination of group of cells. This work highlights how tissue robustness and plasticity can emerge from local and transient feedbacks.

In the second part, I will present our recent attempt to characterize the process of cell extrusion in the pupal notum. We previously showed that caspases activation precede and is required for cell extrusion in the notum, however it remained unclear how caspases would regulate cell extrusion. Contrary to other morphogenetic processes, we characterized an early phase of cell apical constriction which is not associated with any changes of actomyosin concentration/dynamics/activity nore a modulation of cell-cell adhesion. Surprisingly, the initiation of cell extrusion is rather associated with an early disassembly of a medio-apical mesh of microtubules (MTs), which is triggered by caspase activation. Accordingly, we found that MTs modulation is sufficient to transiently modulate cell apical area, while MTs depletion is sufficient to bypass the inhibtion of caspases and restore cell extrusion. This work highlight an important role of MTs for the stabilization of cell apical area which may be relevant in other morphogenetic processes.

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L'étude des interactions mutuelles entre la réponse aux dommages de l'ADN et le métabolisme de l'ARN représente un domaine de recherche émergent/croissant.

Deux cours internationaux Curie ("5e Cours sur la régulation post-transcriptionnelle des gènes " et "3e Cours sur l'intégrité du génome et les maladies humaines") uniront exceptionnellement leurs efforts en 2021 pour fournir des informations de base sur la régulation post-transcriptionnelle des gènes et le maintien de la stabilité du génome, depuis les études mécanistes jusqu'aux approches basées sur les omiques. Vous pouvez consulter le programme pour plus d'informations.

Cette édition aura lieu en format virtuel en temps réel (GMT+1). 

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L'objectif général de ce 3e cours de biologie cellulaire et cancer est de couvrir différents sujets de la biologie cellulaire et de la biologie des cellules cancéreuses, y compris la croissance des cellules et des tissus, la signalisation cellulaire, la division cellulaire, l'organisation des cellules et des tissus à différents niveaux : moléculaire, cellulaire et dans l'organisme vivant. En outre, nous aurons une session consacrée à la physique des tissus.

Ce cours est prévu en présentiel à Paris. Selon les conditions sanitaires et les recommandations du gouvernement français en mai 2021, il pourra se tenir entièrement à distance ou sur un mode hybride.