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

Pablo J Sáez, Pablo Vargas, Kenji F Shoji, Paloma A Harcha, Ana-María Lennon-Duménil, Juan C Sáez (2017 Nov 23)

ATP promotes the fast migration of dendritic cells through the activity of pannexin 1 channels and P2X receptors.

Science signaling : DOI : eaah7107 En savoir plus
Résumé

Upon its release from injured cells, such as infected, transformed, inflamed, or necrotic cells, extracellular adenosine-5′-triphosphate (ATP) acts as a danger signal that recruits phagocytes, such as neutrophils, macrophages, and dendritic cells (DCs), to the site of injury. The sensing of extracellular ATP occurs through purinergic (P2) receptors. We investigated the cellular mechanisms linking purinergic signaling to DC motility. We found that ATP stimulated fast DC motility through an autocrine signaling loop, which was initiated by the activation of P2X receptors and further amplified by pannexin 1 (Panx1) channels. Upon stimulation of the P2X receptor by ATP, Panx1 contributed to fast DC motility by increasing the permeability of the plasma membrane, which resulted in supplementary ATP release. In the absence of Panx1, DCs failed to increase their speed of migration in response to ATP, despite exhibiting a normal P2X receptor-mediated Ca response. In addition to DC migration, Panx1 channel- and P2X receptor-dependent signaling was further required to stimulate the reorganization of the actin cytoskeleton. In vivo, functional Panx1 channels were required for the homing of DCs to lymph nodes, although they were dispensable for DC maturation. These data suggest that P2X receptors and Panx1 channels are crucial players in the regulation of DC migration to endogenous danger signals.

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Sophia Maschalidi, Paula Nunes-Hasler, Clarissa R Nascimento, Ignacio Sallent, Valérie Lannoy, Meriem Garfa-Traore, Nicolas Cagnard, Fernando E Sepulveda, Pablo Vargas, Ana-Maria Lennon-Duménil, Peter van Endert, Thierry Capiod, Nicolas Demaurex, Guillaume Darrasse-Jèze, Bénédicte Manoury (2017 Nov 22)

UNC93B1 interacts with the calcium sensor STIM1 for efficient antigen cross-presentation in dendritic cells.

Nature communications : 1640 : DOI : 10.1038/s41467-017-01601-5 En savoir plus
Résumé

Dendritic cells (DC) have the unique ability to present exogenous antigens via the major histocompatibility complex class I pathway to stimulate naive CD8 T cells. In DCs with a non-functional mutation in Unc93b1 (3d mutation), endosomal acidification, phagosomal maturation, antigen degradation, antigen export to the cytosol and the function of the store-operated-Ca-entry regulator STIM1 are impaired. These defects result in compromised antigen cross-presentation and anti-tumor responses in 3d-mutated mice. Here, we show that UNC93B1 interacts with the calcium sensor STIM1 in the endoplasmic reticulum, a critical step for STIM1 oligomerization and activation. Expression of a constitutively active STIM1 mutant, which no longer binds UNC93B1, restores antigen degradation and cross-presentation in 3d-mutated DCs. Furthermore, ablation of STIM1 in mouse and human cells leads to a decrease in cross-presentation. Our data indicate that the UNC93B1 and STIM1 cooperation is important for calcium flux and antigen cross-presentation in DCs.

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Marine Bretou, Pablo J Sáez, Doriane Sanséau, Mathieu Maurin, Danielle Lankar, Melanie Chabaud, Carmine Spampanato, Odile Malbec, Lucie Barbier, Shmuel Muallem, Paolo Maiuri, Andrea Ballabio, Julie Helft, Matthieu Piel, Pablo Vargas, Ana-Maria Lennon-Duménil (2017 Oct 29)

Lysosome signaling controls the migration of dendritic cells.

Science immunology : DOI : eaak9573 En savoir plus
Résumé

Dendritic cells (DCs) patrol their environment by linking antigen acquisition by macropinocytosis to cell locomotion. DC activation upon bacterial sensing inhibits macropinocytosis and increases DC migration, thus promoting the arrival of DCs to lymph nodes for antigen presentation to T cells. The signaling events that trigger such changes are not fully understood. We show that lysosome signaling plays a critical role in this process. Upon bacterial sensing, lysosomal calcium is released by the ionic channel TRPML1 (transient receptor potential cation channel, mucolipin subfamily, member 1), which activates the actin-based motor protein myosin II at the cell rear, promoting fast and directional migration. Lysosomal calcium further induces the activation of the transcription factor EB (TFEB), which translocates to the nucleus to maintain TRPML1 expression. We found that the TRPML1-TFEB axis results from the down-regulation of macropinocytosis after bacterial sensing by DCs. Lysosomal signaling therefore emerges as a hitherto unexpected link between macropinocytosis, actomyosin cytoskeleton organization, and DC migration.

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Janna Schneppenheim, Ann-Christine Loock, Susann Hüttl, Michaela Schweizer, Renate Lüllmann-Rauch, Hans-Heinrich Oberg, Philipp Arnold, Christian H K Lehmann, Diana Dudziak, Dieter Kabelitz, Ralph Lucius, Ana-Maria Lennon-Duménil, Paul Saftig, Bernd Schröder (2017 May 28)

The Influence of MHC Class II on B Cell Defects Induced by Invariant Chain/CD74 N-Terminal Fragments.

Journal of immunology (Baltimore, Md. : 1950) : 172-185 : DOI : 10.4049/jimmunol.1601533 En savoir plus
Résumé

The invariant chain (CD74) mediates assembly and targeting of MHC class II (MHCII) complexes. In endosomes, CD74 undergoes sequential degradation by different proteases, including cathepsin S (CatS) and the intramembrane protease signal peptide peptidase-like 2a (SPPL2a). In their absence, CD74 N-terminal fragments (NTFs) accumulate. In B cells, such an NTF impairs endosomal trafficking and BCR signal transduction. In mice, this leads to a loss of splenic B cells beyond the transitional stage 1. To gain insight into CD74 determinants and the role of MHCII, we compared B cells from , , and SPPL2a-MHCII double-deficient mice. We assessed differentiation of B cells in bone marrow and spleen and analyzed their endosomal morphology, BCR expression, and signal transduction. We demonstrate that MHCII is dispensable for the B cell phenotype of mice, further supporting a CD74-intrinsic effect. Despite significant vacuolization of endosomal compartments similar to B cells, traditional stage 1 B cells show unimpaired degradation of endocytic cargo, have intact BCR signaling, and do not exhibit any relevant defects in maturation. This could indicate that CD74 NTF-induced structural changes of endosomes are not directly involved in these processes. We further found that the block of CD74 degradation in B cells is incomplete, so that NTF levels are significantly lower than in B cells. This suggests a dose dependency and threshold for the CD74 NTF-associated impairment of B cell signaling and maturation. In addition, different functional properties of the longer, MHCII-bound CD74 NTF could contribute to the milder phenotype of B cells.

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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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