Innate Immunity

Team Publications

Year of publication 2016

Xavier Lahaye, Takeshi Satoh, Matteo Gentili, Silvia Cerboni, Aymeric Silvin, Cécile Conrad, Abdelhakim Ahmed-Belkacem, Elisa C Rodriguez, Jean-François Guichou, Nathalie Bosquet, Matthieu Piel, Roger Le Grand, Megan C King, Jean-Michel Pawlotsky, Nicolas Manel (2016 May 7)

Nuclear Envelope Protein SUN2 Promotes Cyclophilin-A-Dependent Steps of HIV Replication.

Cell reports : DOI : S2211-1247(16)30363-1 Learn more
Summary

During the early phase of replication, HIV reverse transcribes its RNA and crosses the nuclear envelope while escaping host antiviral defenses. The host factor Cyclophilin A (CypA) is essential for these steps and binds the HIV capsid; however, the mechanism underlying this effect remains elusive. Here, we identify related capsid mutants in HIV-1, HIV-2, and SIVmac that are restricted by CypA. This antiviral restriction of mutated viruses is conserved across species and prevents nuclear import of the viral cDNA. Importantly, the inner nuclear envelope protein SUN2 is required for the antiviral activity of CypA. We show that wild-type HIV exploits SUN2 in primary CD4(+) T cells as an essential host factor that is required for the positive effects of CypA on reverse transcription and infection. Altogether, these results establish essential CypA-dependent functions of SUN2 in HIV infection at the nuclear envelope.

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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 Learn more
Summary

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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Matteo Gentili, Nicolas Manel (2016 Mar 25)

cGAS-STING do it again: pivotal role in RNase H2 genetic disease.

The EMBO journal : DOI : e201694226 Learn more
Summary

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Year of publication 2015

Gentili M, Kowal 1, Tkach M, Satoh T, Lahaye X, Conrad C, Boyron M, Lombard B, Durand S, Kroemer G, Loew D, Dalod M, Théry C, Manel N. (2015 Jul 30)

Transmission of innate immune signaling by packaging of cGAMP in viral particles.

Science : DOI : 10.1126/science.aab3628 Learn more
Summary

Infected cells detect viruses through a variety of receptors that initiate cell-intrinsic innate defense responses. Cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase (cGAS) is a cytosolic sensor for many DNA viruses and HIV-1. In response to cytosolic viral DNA, cGAS synthesizes the second messenger 2’3′-cyclic GMP-AMP (cGAMP), which activates antiviral signaling pathways. We show that in cells producing virus, cGAS-synthesized cGAMP can be packaged in viral particles and extracellular vesicles. Viral particles efficiently delivered cGAMP to target cells. cGAMP transfer by viral particles to dendritic cells activated innate immunity and antiviral defenses. Finally, we show that cell-free murine cytomegalovirus and Modified Vaccinia Ankara virus contained cGAMP. Thus, transfer of cGAMP by viruses may represent a defense mechanism to propagate immune responses to uninfected target cells.

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Yanick J Crow, Nicolas Manel (2015 Jun 9)

Aicardi-Goutières syndrome and the type I interferonopathies

Nature Reviews Immunology : 429-40 : DOI : 10.1038/nri3850 Learn more
Summary

Dissection of the genetic basis of Aicardi-Goutières syndrome has highlighted a fundamental link between nucleic acid metabolism, innate immune sensors and type I interferon induction. This had led to the concept of the human interferonopathies as a broader set of Mendelian disorders in which a constitutive upregulation of type I interferon activity directly relates to disease pathology. Here, we discuss the molecular and cellular basis of the interferonopathies, their categorization, future treatment strategies and the insights they provide into normal physiology.

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Adrien Decque, Olivier Joffre, Joao G Magalhaes, Jack-Christophe Cossec, Ronnie Blecher-Gonen, Pierre Lapaquette, Aymeric Silvin, Nicolas Manel, Pierre-Emmanuel Joubert, Jacob-Sebastian Seeler, Matthew L Albert, Ido Amit, Sebastian Amigorena, Anne Dejean (2015 Apr 15)

Sumoylation coordinates the repression of inflammatory and anti-viral gene-expression programs during innate sensing.

Nature immunology : 140-9 : DOI : 10.1038/ni.3342 Learn more
Summary

Innate sensing of pathogens initiates inflammatory cytokine responses that need to be tightly controlled. We found here that after engagement of Toll-like receptors (TLRs) in myeloid cells, deficient sumoylation caused increased secretion of transcription factor NF-κB-dependent inflammatory cytokines and a massive type I interferon signature. In mice, diminished sumoylation conferred susceptibility to endotoxin shock and resistance to viral infection. Overproduction of several NF-κB-dependent inflammatory cytokines required expression of the type I interferon receptor, which identified type I interferon as a central sumoylation-controlled hub for inflammation. Mechanistically, the small ubiquitin-like modifier SUMO operated from a distal enhancer of the gene encoding interferon-β (Ifnb1) to silence both basal and stimulus-induced activity of the Ifnb1 promoter. Therefore, sumoylation restrained inflammation by silencing Ifnb1 expression and by strictly suppressing an unanticipated priming by type I interferons of the TLR-induced production of inflammatory cytokines.

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Xavier Lahaye, Nicolas Manel (2015 Feb 21)

Viral and cellular mechanisms of the innate immune sensing of HIV.

Current opinion in virology : 55-62 : DOI : 10.1016/j.coviro.2015.01.013 Learn more
Summary

HIV-1 replicates in immune cells that normally respond to incoming viruses and induce antiviral immune responses. Under this constant surveillance, how HIV-1 interacts with the host to escape immune control and causes immunopathology is still being untangled. Recently, a series of HIV-1 interactions with innate sensors of viruses expressed by immune target cells have been identified. Here, we review the HIV-1 factors that escape, engage and regulate these innate immune sensors. We discuss the general principles of these interactions as well as the remarkable cell-type specificity of the regulatory mechanisms and their resulting immune responses. Innate sensors directly intersect viral replication with immunity, and understanding their triggering, or lack thereof, improves our ability to design immune interventions.

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Aymeric Silvin, Nicolas Manel (2015 Jan 25)

Innate immune sensing of HIV infection.

Current opinion in immunology : 54-60 : DOI : 10.1016/j.coi.2014.12.003 Learn more
Summary

The ability to sense infections is primordial to preserve organisms. Immune cells express pathogen sensors that induct innate and adaptive immune responses. Understanding how HIV-1 infection defeats these responses in most individuals remains an outstanding challenge. Since HIV-1 targets immune cells, innate immune sensors are remarkably positioned at the nexus of viral replication and immunity. Here, we discuss recent studies that have revealed innate sensing mechanisms of HIV-1 infection in plasmacytoid dendritic cells, monocyte-derived dendritic cells, monocyte-derived macrophages, and CD4+ T cells. These studies help understand how HIV-1 avoids antiviral innate immune sensors and how it induces pathogenic processes. Ultimately, this may contribute to therapy and vaccines.

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Year of publication 2014

Nadia Jeremiah, Bénédicte Neven, Matteo Gentili, Isabelle Callebaut, Sophia Maschalidi, Marie-Claude Stolzenberg, Nicolas Goudin, Marie-Louis Frémond, Patrick Nitschke, Thierry J Molina, Stéphane Blanche, Capucine Picard, Gillian I Rice, Yanick J Crow, Nicolas Manel, Alain Fischer, Brigitte Bader-Meunier, Frédéric Rieux-Laucat (2014 Nov 18)

Inherited STING-activating mutation underlies a familial inflammatory syndrome with lupus-like manifestations.

The Journal of clinical investigation : 5516-20 : DOI : 10.1172/JCI79100 Learn more
Summary

Innate immunity to viral infection involves induction of the type I IFN response; however, dysfunctional regulation of this pathway leads to inappropriate inflammation. Here, we evaluated a nonconsanguineous family of mixed European descent, with 4 members affected by systemic inflammatory and autoimmune conditions, including lupus, with variable clinical expression. We identified a germline dominant gain-of-function mutation in TMEM173, which encodes stimulator of type I IFN gene (STING), in the affected individuals. STING is a key signaling molecule in cytosolic DNA-sensing pathways, and STING activation normally requires dimerization, which is induced by 2’3′ cyclic GMP-AMP (cGAMP) produced by the cGAMP synthase in response to cytosolic DNA. Structural modeling supported constitutive activation of the mutant STING protein based on stabilized dimerization. In agreement with the model predictions, we found that the STING mutant spontaneously localizes in the Golgi of patient fibroblasts and is constitutively active in the absence of exogenous 2’3′-cGAMP in vitro. Accordingly, we observed elevated serum IFN activity and a type I IFN signature in peripheral blood from affected family members. These findings highlight the key role of STING in activating both the innate and adaptive immune responses and implicate aberrant STING activation in features of human lupus.

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Xavier Lahaye, Nicolas Manel (2014 Jul 12)

[HIV-2 reveals an antiviral mechanism of detection by innate immunity].

Médecine sciences : M/S : 610-3 : DOI : 10.1051/medsci/20143006004 Learn more
Summary

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Maxime Touzot, Maximilien Grandclaudon, Antonio Cappuccio, Takeshi Satoh, Carolina Martinez-Cingolani, Nicolas Servant, Nicolas Manel, Vassili Soumelis (2014 May 29)

Combinatorial flexibility of cytokine function during human T helper cell differentiation.

Nature communications : 3987 : DOI : 10.1038/ncomms4987 Learn more
Summary

In an inflammatory microenvironment, multiple cytokines may act on the same target cell, creating the possibility for combinatorial interactions. How these may influence the system-level function of a given cytokine is unknown. Here we show that a single cytokine, interferon (IFN)-alpha, can generate multiple transcriptional signatures, including distinct functional modules of variable flexibility, when acting in four cytokine environments driving distinct T helper cell differentiation programs (Th0, Th1, Th2 and Th17). We provide experimental validation of a chemokine, cytokine and antiviral modules differentially induced by IFN-α in Th1, Th2 and Th17 environments. Functional impact is demonstrated for the antiviral response, with a lesser IFN-α-induced protection to HIV-1 and HIV-2 infection in a Th17 context. Our results reveal that a single cytokine can induce multiple transcriptional and functional programs in different microenvironments. This combinatorial flexibility creates a previously unrecognized diversity of responses, with potential impact on disease physiopathology and cytokine therapy.

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Year of publication 2013

Marina Colombo, Catarina Moita, Guillaume van Niel, Joanna Kowal, James Vigneron, Philippe Benaroch, Nicolas Manel, Luis F Moita, Clotilde Théry, Graça Raposo (2013 Oct 8)

Analysis of ESCRT functions in exosome biogenesis, composition and secretion highlights the heterogeneity of extracellular vesicles.

Journal of cell science : 5553-65 : DOI : 10.1242/jcs.128868 Learn more
Summary

Exosomes are extracellular vesicles (EVs) secreted upon fusion of endosomal multivesicular bodies (MVBs) with the plasma membrane. The mechanisms involved in their biogenesis have not yet been fully identified although they could be used to modulate exosome formation and therefore are a promising tool in understanding exosome functions. We have performed an RNA interference screen targeting 23 components of the endosomal sorting complex required for transport (ESCRT) machinery and associated proteins in MHC class II (MHC II)-expressing HeLa-CIITA cells. Silencing of HRS, STAM1 or TSG101 reduced the secretion of EV-associated CD63 and MHC II but each gene altered differently the size and/or protein composition of secreted EVs, as quantified by immuno-electron microscopy. By contrast, depletion of VPS4B augmented this secretion while not altering the features of EVs. For several other ESCRT subunits, it was not possible to draw any conclusions about their involvement in exosome biogenesis from the screen. Interestingly, silencing of ALIX increased MHC II exosomal secretion, as a result of an overall increase in intracellular MHC II protein and mRNA levels. In human dendritic cells (DCs), ALIX depletion also increased MHC II in the cells, but not in the released CD63-positive EVs. Such differences could be attributed to a greater heterogeneity in size, and higher MHC II and lower CD63 levels in vesicles recovered from DCs as compared with HeLa-CIITA. The results reveal a role for selected ESCRT components and accessory proteins in exosome secretion and composition by HeLa-CIITA. They also highlight biogenetic differences in vesicles secreted by a tumour cell line and primary DCs.

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Silvia Cerboni, Matteo Gentili, Nicolas Manel (2013 Sep 28)

Diversity of pathogen sensors in dendritic cells.

Advances in immunology : 211-37 : DOI : 10.1016/B978-0-12-417028-5.00008-9 Learn more
Summary

Dendritic cells (DCs) associate the capacity to sense pathogens with the initiation of adaptive immunity. Pathogens can be sensed through pathogen-associated molecular patterns by pathogen-recognition receptors expressed on host cells. Pathogen-encoded activities can also be sensed when they modify normal host cellular processes. The diversity of pathogen sensors has been highlighted by the identification of several cytosolic sensors involved in the recognition of nucleic acids from pathogens. The number of these pathogen cytosolic sensors has dramatically increased recently. Different DC populations appear to be equipped with distinct sensors but the precise expression pattern and the regulation of these sensors remain to be established, especially in humans. The engagement of sensors in DCs by pathogens leads to antipathogen effects through multiple mechanisms including interferon responses and promotes effector pathways that can shape the adaptive immune response. How the diversity of cytosolic pathogen sensors impacts these processes is incompletely understood. Investigating the expression, regulation, and crosstalk of the sensors should shed light on how pathogen sensing impacts pathogen replication and host immune responses.

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Xavier Lahaye, Takeshi Satoh, Matteo Gentili, Silvia Cerboni, Cécile Conrad, Ilse Hurbain, Ahmed El Marjou, Christine Lacabaratz, Jean-Daniel Lelièvre, Nicolas Manel (2013 Sep 6)

The capsids of HIV-1 and HIV-2 determine immune detection of the viral cDNA by the innate sensor cGAS in dendritic cells.

Immunity : 1132-42 : DOI : 10.1016/j.immuni.2013.11.002 Learn more
Summary

HIV-2 is less pathogenic for humans than HIV-1 and might provide partial cross-protection from HIV-1-induced pathology. Although both viruses replicate in the T cells of infected patients, only HIV-2 replicates efficiently in dendritic cells (DCs) and activates innate immune pathways. How HIV is sensed in DC is unknown. Capsid-mutated HIV-2 revealed that sensing by the host requires viral cDNA synthesis, but not nuclear entry or genome integration. The HIV-1 capsid prevented viral cDNA sensing up to integration, allowing the virus to escape innate recognition. In contrast, DCs sensed capsid-mutated HIV-1 and enhanced stimulation of T cells in the absence of productive infection. Finally, we found that DC sensing of HIV-1 and HIV-2 required the DNA sensor cGAS. Thus, the HIV capsid is a determinant of innate sensing of the viral cDNA by cGAS in dendritic cells. This pathway might potentially be harnessed to develop effective vaccines against HIV-1.

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Takeshi Satoh, Nicolas Manel (2013 Jan 19)

Gene transduction in human monocyte-derived dendritic cells using lentiviral vectors.

Methods in molecular biology (Clifton, N.J.) : 401-9 : DOI : 10.1007/978-1-62703-218-6_30 Learn more
Summary

Monocyte-derived dendritic cells (MDDCs) are widely used in the field of human immunology. Although a variety of gene delivery procedures have been used in MDDC, it has remained difficult to achieve robust gene transductions. In this chapter, we describe a procedure for high efficiency gene transduction in human MDDCs using lentiviral vectors. Gene transduction based on HIV-1-derived lentiviral vectors is restricted at the level of reverse transcription by the cellular protein SAMHD1 in MDDCs. Co-transduction of the MDDCs with helper particles derived from SIVmac that contain the viral protein Vpx removes this restriction, leading to a drastic increase in the rate of gene transduction. This procedure leads to nontoxic, efficient and stable transduction in MDDCs. It can be applied to any HIV-1-derived lentiviral vector, including shRNA lentiviral vectors for RNAi. Transduced MDDCs are not activated by the transduction and can be activated normally by TLR ligands.

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