Dynamique spatio-temporelle des cellules du système immunitaire

Publications de l’équipe

Année de publication : 2019

Daisuke Inoue, Dorian Obino, Judith Pineau, Francesca Farina, Jérémie Gaillard, Christophe Guerin, Laurent Blanchoin, Ana-Maria Lennon-Duménil, Manuel Théry (2019 Mar 24)

Actin filaments regulate microtubule growth at the centrosome.

The EMBO journal : DOI : e99630 En savoir plus
Résumé

The centrosome is the main microtubule-organizing centre. It also organizes a local network of actin filaments. However, the precise function of the actin network at the centrosome is not well understood. Here, we show that increasing densities of actin filaments at the centrosome of lymphocytes are correlated with reduced amounts of microtubules. Furthermore, lymphocyte activation resulted in disassembly of centrosomal actin and an increase in microtubule number. To further investigate the direct crosstalk between actin and microtubules at the centrosome, we performed reconstitution assays based on (i) purified centrosomes and (ii) on the co-micropatterning of microtubule seeds and actin filaments. These two assays demonstrated that actin filaments constitute a physical barrier blocking elongation of nascent microtubules. Finally, we showed that cell adhesion and cell spreading lead to lower densities of centrosomal actin, thus resulting in higher microtubule growth. We therefore propose a novel mechanism, by which the number of centrosomal microtubules is regulated by cell adhesion and actin-network architecture.

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Année de publication : 2018

Dorian Obino, Luc Fetler, Andrea Soza, Odile Malbec, Juan José Saez, Mariana Labarca, Claudia Oyanadel, Felipe Del Valle Batalla, Nicolas Goles, Aleksandra Chikina, Danielle Lankar, Fabián Segovia-Miranda, Camille Garcia, Thibaut Léger, Alfonso Gonzalez, Marion Espéli, Ana-Maria Lennon-Duménil, Maria-Isabel Yuseff (2018 Dec 13)

Galectin-8 Favors the Presentation of Surface-Tethered Antigens by Stabilizing the B Cell Immune Synapse.

Cell reports : 3110-3122.e6 : DOI : S2211-1247(18)31815-1 En savoir plus
Résumé

Complete activation of B cells relies on their capacity to extract tethered antigens from immune synapses by either exerting mechanical forces or promoting their proteolytic degradation through lysosome secretion. Whether antigen extraction can also be tuned by local cues originating from the lymphoid microenvironment has not been investigated. We here show that the expression of Galectin-8-a glycan-binding protein found in the extracellular milieu, which regulates interactions between cells and matrix proteins-is increased within lymph nodes under inflammatory conditions where it enhances B cell arrest phases upon antigen recognition in vivo and promotes synapse formation during BCR recognition of immobilized antigens. Galectin-8 triggers a faster recruitment and secretion of lysosomes toward the B cell-antigen contact site, resulting in efficient extraction of immobilized antigens through a proteolytic mechanism. Thus, extracellular cues can determine how B cells sense and extract tethered antigens and thereby tune B cell responses in vivo.

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Mirjana Weimershaus, François-Xavier Mauvais, Loredana Saveanu, Cézaire Adiko, Joël Babdor, Anastasia Abramova, Sebastian Montealegre, Myriam Lawand, Irini Evnouchidou, Katharina Julia Huber, Alexandra Chadt, Markus Zwick, Pablo Vargas, Michael Dussiot, Ana Maria Lennon-Dumenil, Thomas Brocker, Hadi Al-Hasani, Peter van Endert (2018 Sep 27)

Innate Immune Signals Induce Anterograde Endosome Transport Promoting MHC Class I Cross-Presentation.

Cell reports : 3568-3581 : DOI : S2211-1247(18)31312-3 En savoir plus
Résumé

Both cross-presentation of antigens by dendritic cells, a key pathway triggering T cell immunity and immune tolerance, and survival of several pathogens residing in intracellular vacuoles are intimately linked to delayed maturation of vesicles containing internalized antigens and microbes. However, how early endosome or phagosome identity is maintained is incompletely understood. We show that Toll-like receptor 4 (TLR4) and Fc receptor ligation induces interaction of the GTPase Rab14 with the kinesin KIF16b mediating plus-end-directed microtubule transport of endosomes. As a result, Rab14 recruitment to phagosomes delays their maturation and killing of an internalized pathogen. Enhancing anterograde transport by overexpressing Rab14, promoting the GTP-bound Rab14 state, or inhibiting retrograde transport upregulates cross-presentation. Conversely, reducing Rab14 expression, destabilizing Rab14 endosomes, and inhibiting anterograde microtubule transport by Kif16b knockdown compromise cross-presentation. Therefore, regulation of early endosome trafficking by innate immune signals is a critical parameter in cross-presentation by dendritic cells.

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Sandra Sofía Edwards, María Graciela Delgado, Guilherme Pedreira de Freitas Nader, Matthieu Piel, Yohanns Bellaïche, Ana María Lennon-Duménil, Álvaro Glavic (2018 Aug 11)

An in vitro method for studying subcellular rearrangements during cell polarization in Drosophila melanogaster hemocytes.

Mechanisms of development : 277-286 : DOI : S0925-4773(18)30062-5 En savoir plus
Résumé

Thanks to the power of Drosophila genetics, this animal model has been a precious tool for scientists to uncover key processes associated to innate immunity. The fly immune system relies on a population of macrophage-like cells, also referred to as hemocytes, which are highly migratory and phagocytic, and can easily be followed in vivo. These cells have shown to play important roles in fly development, both at the embryonic and pupal stages. However, there is no robust assay for the study of hemocyte migration in vitro, which limits our understanding of the molecular mechanisms involved. Here, we contribute to fill this gap by showing that hemocytes adopt a polarized morphology upon ecdysone stimulation, allowing the study of the cytoskeleton rearrangements and organelle reorganization that take place during the first step of cell locomotion.

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Felipe Del Valle Batalla, Ana-María Lennon-Dumenil, María-Isabel Yuseff (2018 Jun 24)

Tuning B cell responses to antigens by cell polarity and membrane trafficking.

Molecular immunology : 140-145 : DOI : S0161-5890(18)30214-1 En savoir plus
Résumé

The capacity of B lymphocytes to produce specific antibodies, particularly broadly neutralizing antibodies that provide immunity to viral pathogens has positioned them as valuable therapeutic targets for immunomodulation. To become competent as antibody secreting cells, B cells undergo a series of activation steps, which are triggered by the recognition of antigens frequently displayed on the surface of other presenting cells. Such antigens elicit the formation of an immune synapse (IS), where local cytoskeleton rearrangements coupled to mechanical forces and membrane trafficking orchestrate the extraction and processing of antigens in B cells. In this review, we discuss the molecular mechanisms that regulate polarized membrane trafficking and mechanical properties of the immune synapse, as well as the potential extracellular cues from the environment, which may impact the ability of B cells to sense and acquire antigens at the immune synapse. An integrated view of the diverse cellular mechanisms that shape the immune synapse will provide a better understanding on how B cells are efficiently activated.

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Hélène D Moreau, Matthieu Piel, Raphaël Voituriez, Ana-Maria Lennon-Duménil (2018 May 22)

Integrating Physical and Molecular Insights on Immune Cell Migration.

Trends in immunology : 632-643 : DOI : S1471-4906(18)30084-X En savoir plus
Résumé

The function of most immune cells depends on their ability to migrate through complex microenvironments, either randomly to patrol for the presence of antigens or directionally to reach their next site of action. The actin cytoskeleton and its partners are key conductors of immune cell migration as they control the intrinsic migratory properties of leukocytes as well as their capacity to respond to cues present in their environment. In this review we focus on the latest discoveries regarding the role of the actomyosin cytoskeleton in optimizing immune cell migration in complex environments, with a special focus on recent insights provided by physical modeling.

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Pablo J Sáez, Juan C Sáez, Ana-María Lennon-Duménil, Pablo Vargas (2018 May 2)

Role of calcium permeable channels in dendritic cell migration.

Current opinion in immunology : 74-80 : DOI : S0952-7915(18)30016-5 En savoir plus
Résumé

Calcium ion (Ca) is an essential second messenger involved in multiple cellular and subcellular processes. Ca can be released and sensed globally or locally within cells, providing complex signals of variable amplitudes and time-scales. The key function of Ca in the regulation of acto-myosin contractility has provided a simple explanation for its role in the regulation of immune cell migration. However, many questions remain, including the identity of the Ca stores, channels and upstream signals involved in this process. Here, we focus on dendritic cells (DCs), because their immune sentinel function heavily relies on their capacity to migrate within tissues and later on between tissues and lymphoid organs. Deciphering the mechanisms by which cytoplasmic Ca regulate DC migration should shed light on their role in initiating and tuning immune responses.

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Cesar Oyarce, Sebastián Cruz-Gomez, Felipe Galvez-Cancino, Pablo Vargas, Hélène D Moreau, Natalia Diaz-Valdivia, Jorge Diaz, Flavio Andres Salazar-Onfray, Rodrigo Pacheco, Ana Maria Lennon-Dumenil, Andrew F G Quest, Alvaro Lladser (2018 Jan 13)

Caveolin-1 Expression Increases upon Maturation in Dendritic Cells and Promotes Their Migration to Lymph Nodes Thereby Favoring the Induction of CD8 T Cell Responses.

Frontiers in immunology : 1794 : DOI : 10.3389/fimmu.2017.01794 En savoir plus
Résumé

Dendritic cell (DC) trafficking from peripheral tissues to lymph nodes (LNs) is a key step required to initiate T cell responses against pathogens as well as tumors. In this context, cellular membrane protrusions and the actin cytoskeleton are essential to guide DC migration towards chemotactic signals. Caveolin-1 (CAV1) is a scaffolding protein that modulates signaling pathways leading to remodeling of the actin cytoskeleton and enhanced migration of cancer cells. However, whether CAV1 is relevant for DC function and specifically for DC migration to LNs is unknown. Here, we show that CAV1 expression is upregulated in DCs upon LPS- and TNF-α-induced maturation. CAV1 deficiency did not affect differentiation, maturation, or the ability of DCs to activate CD8 T cells . However, CAV1-deficient (CAV1) DCs displayed reduced trafficking to draining LNs in control and inflammatory conditions. , CAV1 DCs showed reduced directional migration in CCL21 gradients in transwell assays without affecting migration velocity in confined microchannels or three-dimensional collagen matrices. In addition, CAV1 DCs displayed reduced activation of the small GTPase Rac1, a regulator of actin cytoskeletal remodeling, and lower numbers of F-actin-forming protrusions. Furthermore, mice adoptively transferred with peptide-pulsed CAV1 DCs showed reduced CD8 T cell responses and antitumor protection. Our results suggest that CAV1 promotes the activation of Rac1 and the formation of membrane protrusions that favor DC chemotactic trafficking toward LNs where they can initiate cytotoxic T cell responses.

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Année de publication : 2017

Hélène D Moreau, Philippe Bousso, Ana-Maria Lennon-Duménil (2017 Mar 4)

Microchannels for the Study of T Cell Immunological Synapses and Kinapses.

Methods in molecular biology (Clifton, N.J.) : 347-354 : DOI : 10.1007/978-1-4939-6881-7_20 En savoir plus
Résumé

T Cells can form very stable (synapses) or very transient and migratory (kinapses) contacts with antigen-presenting cells. Here, we describe how microchannels can be used to conveniently study the distinct dynamics of T cells during antigen recognition. Microchannels provide a controlled confined environment that promotes T cell migration and recapitulates kinapse and synapse behaviors when coated with appropriate pMHC molecules. We also depict the advantages of this in vitro approach for addressing mechanistic issues and for analysis.

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Année de publication : 2016

Shinelle Menezes, Daisy Melandri, Giorgio Anselmi, Thibaut Perchet, Jakob Loschko, Juan Dubrot, Rajen Patel, Emmanuel L Gautier, Stéphanie Hugues, M Paula Longhi, Jake Y Henry, Sergio A Quezada, Grégoire Lauvau, Ana-Maria Lennon-Duménil, Enrique Gutiérrez-Martínez, Alain Bessis, Elisa Gomez-Perdiguero, Christian E Jacome-Galarza, Hannah Garner, Frederic Geissmann, Rachel Golub, Michel C Nussenzweig, Pierre Guermonprez (2016 Dec 22)

The Heterogeneity of Ly6C(hi) Monocytes Controls Their Differentiation into iNOS(+) Macrophages or Monocyte-Derived Dendritic Cells.

Immunity : 1205-1218 : DOI : S1074-7613(16)30483-6 En savoir plus
Résumé

Inflammation triggers the differentiation of Ly6C(hi) monocytes into microbicidal macrophages or monocyte-derived dendritic cells (moDCs). Yet, it is unclear whether environmental inflammatory cues control the polarization of monocytes toward each of these fates or whether specialized monocyte progenitor subsets exist before inflammation. Here, we have shown that naive monocytes are phenotypically heterogeneous and contain an NR4A1- and Flt3L-independent, CCR2-dependent, Flt3(+)CD11c(-)MHCII(+)PU.1(hi) subset. This subset acted as a precursor for FcγRIII(+)PD-L2(+)CD209a(+), GM-CSF-dependent moDCs but was distal from the DC lineage, as shown by fate-mapping experiments using Zbtb46. By contrast, Flt3(-)CD11c(-)MHCII(-)PU.1(lo) monocytes differentiated into FcγRIII(+)PD-L2(-)CD209a(-)iNOS(+) macrophages upon microbial stimulation. Importantly, Sfpi1 haploinsufficiency genetically distinguished the precursor activities of monocytes toward moDCs or microbicidal macrophages. Indeed, Sfpi1(+/-) mice had reduced Flt3(+)CD11c(-)MHCII(+) monocytes and GM-CSF-dependent FcγRIII(+)PD-L2(+)CD209a(+) moDCs but generated iNOS(+) macrophages more efficiently. Therefore, intercellular disparities of PU.1 expression within naive monocytes segregate progenitor activity for inflammatory iNOS(+) macrophages or moDCs.

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Paolo Pierobon, Ana-Maria Lennon-Duménil (2016 Dec 22)

To use or not to use the force: How B lymphocytes extract surface-tethered antigens.

The Journal of cell biology : DOI : jcb.201612043 En savoir plus
Résumé

Using an exquisite cell imaging approach based on DNA nanosensors, Spillane and Tolar (2016. J. Cell Biol. https://doi.org/10.1083/jcb.201607064) explore how the physical properties of antigen-presenting cell surfaces affect how B cells internalize surface-tethered antigens. Soft and flexible surfaces promote mechanical force-mediated antigen extraction, whereas stiff surfaces lead to enzyme-mediated antigen release before subsequent internalization.

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M Raab, M Gentili, H de Belly, H R Thiam, P Vargas, A J Jimenez, F Lautenschlaeger, Raphaël Voituriez, A M Lennon-Duménil, N Manel, M Piel (2016 Apr 15)

ESCRT III repairs nuclear envelope ruptures during cell migration to limit DNA damage and cell death

Science (New York, N.Y.) : DOI : 10.1126/science.aad7611 En savoir plus
Résumé

In eukaryotic cells, the nuclear envelope separates the genomic DNA from the cytoplasmic space and regulates protein trafficking between the two compartments. This barrier is only transiently dissolved during mitosis. Here we found that it also opened at high frequency in migrating mammalian cells during interphase, allowing nuclear proteins to leak out and cytoplasmic proteins to leak in. This transient opening was caused by nuclear deformation and was rapidly repaired in an ESCRT (endosomal sorting complexes required for transport)-dependent manner. DNA double strand breaks coincided with nuclear envelope opening events. As a consequence, survival of cells migrating through confining environments depended on efficient nuclear envelope and DNA repair machineries. Nuclear envelope opening in migrating leukocytes could potentially have important consequences for normal and pathological immune responses.

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Dorian Obino, Francesca Farina, Odile Malbec, Pablo J Sáez, Mathieu Maurin, Jérémie Gaillard, Florent Dingli, Damarys Loew, Alexis Gautreau, Maria-Isabel Yuseff, Laurent Blanchoin, Manuel Théry, Ana-Maria Lennon-Duménil (2016 Mar 19)

Actin nucleation at the centrosome controls lymphocyte polarity

Nature communications : 10969 : DOI : 10.1038/ncomms10969 En savoir plus
Résumé

Cell polarity is required for the functional specialization of many cell types including lymphocytes. A hallmark of cell polarity is the reorientation of the centrosome that allows repositioning of organelles and vesicles in an asymmetric fashion. The mechanisms underlying centrosome polarization are not fully understood. Here we found that in resting lymphocytes, centrosome-associated Arp2/3 locally nucleates F-actin, which is needed for centrosome tethering to the nucleus via the LINC complex. Upon lymphocyte activation, Arp2/3 is partially depleted from the centrosome as a result of its recruitment to the immune synapse. This leads to a reduction in F-actin nucleation at the centrosome and thereby allows its detachment from the nucleus and polarization to the synapse. Therefore, F-actin nucleation at the centrosome-regulated by the availability of the Arp2/3 complex-determines its capacity to polarize in response to external stimuli.

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Hawa-Racine Thiam, Pablo Vargas, Nicolas Carpi, Carolina Lage Crespo, Matthew Raab, Emmanuel Terriac, Megan C King, Jordan Jacobelli, Arthur S Alberts, Theresia Stradal, Ana-Maria Lennon-Dumenil, Matthieu Piel (2016 Mar 16)

Perinuclear Arp2/3-driven actin polymerization enables nuclear deformation to facilitate cell migration through complex environments.

Nature communications : 10997 : DOI : 10.1038/ncomms10997 En savoir plus
Résumé

Cell migration has two opposite faces: although necessary for physiological processes such as immune responses, it can also have detrimental effects by enabling metastatic cells to invade new organs. In vivo, migration occurs in complex environments and often requires a high cellular deformability, a property limited by the cell nucleus. Here we show that dendritic cells, the sentinels of the immune system, possess a mechanism to pass through micrometric constrictions. This mechanism is based on a rapid Arp2/3-dependent actin nucleation around the nucleus that disrupts the nuclear lamina, the main structure limiting nuclear deformability. The cells’ requirement for Arp2/3 to pass through constrictions can be relieved when nuclear stiffness is decreased by suppressing lamin A/C expression. We propose a new role for Arp2/3 in three-dimensional cell migration, allowing fast-moving cells such as leukocytes to rapidly and efficiently migrate through narrow gaps, a process probably important for their function.

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Année de publication : 2015

Pablo Vargas, Mélanie Chabaud, Hawa-Racine Thiam, Danielle Lankar, Matthieu Piel, Ana-Maria Lennon-Dumenil (2015 Dec 20)

Study of dendritic cell migration using micro-fabrication.

Journal of immunological methods : 30-4 : DOI : 10.1016/j.jim.2015.12.005 En savoir plus
Résumé

Cell migration is a hallmark of dendritic cells (DCs) function. It is needed for DCs to scan their environment in search for antigens as well as to reach lymphatic organs in order to trigger T lymphocyte’s activation. Such interaction leads to tolerance in the case of DCs migrating under homeostatic conditions or to immunity in the case of DCs migrating upon encounter with pathogen-associated molecular patterns. Cell migration is therefore essential for DCs to transfer information from peripheral tissues to lymphoid organs, thereby linking innate to adaptive immunity. This stresses the need to unravel the molecular mechanisms involved. However, the tremendous complexity of the tissue microenvironment as well as the limited spatio-temporal resolution of in vivo imaging techniques has made this task difficult. To bypass this problem, we have developed microfabrication-based experimental tools that are compatible with high-resolution imaging. Here, we will discuss how such devices can be used to study DC migration under controlled conditions that mimic their physiological environment in a robust quantitative manner.

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