Polarisation et rôle des macrophages dans des contextes inflammatoires aigus et chroniques

Les cellules de l'immunité innée sont impliquées dans divers processus tels que l'initiation d'une réponse inflammatoire et les mécanismes de résolution de l'inflammation. Le premier objectif de ma thèse a permis de caractériser, dans un modèle de péritonite aigüe induite par le thioglycolate, les mécanismes cellulaires et moléculaires impliqués dans les processus résolutifs à la fois dans la cavité péritonéale et l'omentum. Le second objectif visait à étudier la réponse inflammatoire mise en jeu au cours de la tuberculose. J'ai montré que M. tuberculosis est capable de moduler à distance le phénotype et la fonction des monocytes, vers un profil immuno-régulateur. Ceci permettrait à la bactérie de recruter sur le site infectieux des cellules moins compétentes pour contrôler l'infection afin de favoriser sa multiplication et sa survie. Ensemble ces résultats permettent de mieux comprendre les mécanismes de l'inflammation lors de pathologies aigües et chroniquesInnate immune cells are involved in different processes such as the initiation of an inflammatory response and the resolution of inflammation mechanisms. The first part of my work characterized, in a model of acute peritonitis induced by thioglycolate, the molecular and cellular mechanisms involved during the resolutive processes both in the peritoneal cavity and in the omentum. The second part of my work aimed at studying the immune mechanisms involved during tuberculosis. I showed that M. tuberculosis is able to remotely modulate the phenotype and the function of monocytes, towards an immune-regulatory phenotype. This would allow the bacterium to recruit to the infectious site immune cells less competent to control the infection in order to promote its own fitness. Together these results provide new insights for the understanding of the inflammatory mechanisms in acute and chronic context

Hck contributes to bone homeostasis by controlling the recruitment of osteoclast precursors

ABSTRACT In osteoclasts, Src controls podosome organization and bone degradation, which leads to an osteopetrotic phenotype in src ؊/؊ mice. Since this phenotype was even more severe in src ؊/؊ hck ؊/؊ mice, we examined the individual contribution of Hck in bone homeostasis. Compared to wt mice, hck ؊/؊ mice exhibited an osteopetrotic phenotype characterized by an increased density of trabecular bone and decreased bone degradation, although osteoclastogenesis was not impaired. Podosome organization and matrix degradation were found to be defective in hck ؊/؊ osteoclast precursors (preosteoclast) but were normal in mature hck ؊/؊ osteoclasts, probably through compensation by Src, which was specifically overexpressed in mature osteoclasts. As a consequence of podosome defects, the 3-dimensional migration of hck ؊/؊ preosteoclasts was strongly affected in vitro. In vivo, this translated by altered bone homing of preosteoclasts in hck ؊/؊ mice: in metatarsals of 1-wk-old mice, when bone formation strongly depends on the recruitment of these cells, reduced numbers of osteoclasts and abnormal developing trabecular bone were observed. This phenotype was still detectable in adults. In summmary, Hck is one of the very few effectors of preosteoclast recruitment described to date and thereby plays a critical role in bone remodeling.-Vérollet, C., Gallois, A., Dacquin, R., Lastrucci, C., Pandruvada, S. M. N., Ortega, N., Poincloux, R., Behar, A., Cougoule, C., Lowell, C., Al Saati, T., Jurdic, P., Maridonneau-Parini, I. Hck contributes to bone homeostasis by controlling the recruitment of osteoclast precursors. FASEB J. 27, 3608 -3618 (2013). www.fasebj.org Key Words: osteopetrosis ⅐ cell migration ⅐ podosomes ⅐ Src tyrosine kinases Bone is renewed continuously by a process known as bone remodeling. Bone remodeling is accomplished by 3 cell types: osteocytes, osteoblasts, and osteoclasts (OCs). Osteocytes are the mechanical sensors of bone that regulate osteoclast formation. Osteoblasts synthetize the matrix and promote its mineralization, while OCs are responsible for degradation of bones during bone development, homeostasis, and repair. The formation and degradation of bone are tightly balanced in both time and space. A dysregulation of this tight balance between bone formation and bone degradation may result either in loss of bone mass, such as in osteoporosis, or in contrast, in a progressive increase in bone mass, such as in osteopetrosis. Degrading OCs are large multinucleated giant cells formed by the differentiation and fusion of mononuclear monocyte lineage precursors after stimulation by receptor activator of nuclear factor -B ligand (RANKL) and macrophage colony-stimulationg factor (M-CSF) (1-3). They are characterized by high levels of cathepsin K and tartrate resistant acidic phosphatase (TRAP) activities, whic

Tuberculosis is associated with expansion of a motile, permissive and immunomodulatory CD16(+) monocyte population via the IL-10/STAT3 axis

The human CD14+ monocyte compartment is composed by two subsets based on CD16 expression. We previously reported that this compartment is perturbed in tuberculosis (TB) patients, as reflected by the expansion of CD16+ monocytes along with disease severity. Whether this unbalance is beneficial or detrimental to host defense remains to be elucidated. Here in the context of active TB, we demonstrate that human monocytes are predisposed to differentiate towards an anti-inflammatory (M2-like) macrophage activation program characterized by theCD16+CD163+MerTK+pSTAT3+ phenotype and functional properties such as enhanced protease-dependent motility, pathogen permissivity and immunomodulation. This process is dependent on STAT3 activation, and loss-of-function experiments point towards a detrimental role in host defense against TB. Importantly, we provide a critical correlation between the abundance of the CD16+CD163+MerTK+pSTAT3+ cells and the progression of the disease either at the local level in a non-human primate tuberculous granuloma context, or at the systemic level through the detection of the soluble form of CD163 in human sera. Collectively, this study argues for the pathogenic role of the CD16+CD163+MerTK+pSTAT3+ monocyte-to-macrophage differentiation program and its potential as a target for TB therapy,and promotes the detection of circulating CD163 as a potential biomarker for disease progression and monitoringof treatment efficacy.Fil: Lastrucci, Claire. Centre National de la Recherche Scientifique; FranciaFil: Bénard, Alan. Centre National de la Recherche Scientifique; FranciaFil: Balboa, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Pingris, Karine. Centre National de la Recherche Scientifique; FranciaFil: Souriant, Shanti. Centre National de la Recherche Scientifique; FranciaFil: Poincloux, Renaud. Centre National de la Recherche Scientifique; FranciaFil: Al Saati, Talal. Inserm; FranciaFil: Rasolofo, Voahangy. Pasteur Institute in Antananarivo; MadagascarFil: González Montaner, Pablo. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas ; ArgentinaFil: Inwentarz, Sandra. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas ; ArgentinaFil: Moraña, Eduardo José. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas ; ArgentinaFil: Kondova, Ivanela. Biomedical Primate Research Centre; Países BajosFil: Verreck, Franck A. W.. Biomedical Primate Research Centre; Países BajosFil: Sasiain, María del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Neyrolles, Olivier. Centre National de la Recherche Scientifique; FranciaFil: Maridonneau Parini, Isabel. Centre National de la Recherche Scientifique; FranciaFil: Lugo Villarino, Geanncarlo. Centre National de la Recherche Scientifique; FranciaFil: Cougoule, Celine. Centre National de la Recherche Scientifique; Franci

Simple and complex retinal dystrophies are associated with profoundly different disease networks

Retinopathies are a group of monogenetic or complex retinal diseases associated with high unmet medical need. Monogenic disorders are caused by rare genetic variation and usually arise early in life. Other diseases, such as age-related macular degeneration (AMD), develop late in life and are considered to be of complex origin as they develop from a combination of genetic, ageing, environmental and lifestyle risk factors. Here, we contrast the underlying disease networks and pathological mechanisms of monogenic as opposed to complex retinopathies, using AMD as an example of the latter. We show that, surprisingly, genes associated with the different forms of retinopathies in general do not overlap despite their overlapping retinal phenotypes. Further, AMD risk genes participate in multiple networks with interaction partners that link to different ubiquitous pathways affecting general tissue integrity and homeostasis. Thus AMD most likely represents an endophenotype with differing underlying pathogenesis in different subjects. Localising these pathomechanisms and processes within and across different retinal anatomical compartments provides a novel representation of AMD that may be extended to complex disease in general. This approach may generate improved treatment options that target multiple processes with the aim of restoring tissue homeostasis and maintaining vision

Simple and complex retinal dystrophies are associated with profoundly different disease networks

Retinopathies are a group of monogenetic or complex retinal diseases associated with high unmet medical need. Monogenic disorders are caused by rare genetic variation and usually arise early in life. Other diseases, such as age-related macular degeneration (AMD), develop late in life and are considered to be of complex origin as they develop from a combination of genetic, ageing, environmental and lifestyle risk factors. Here, we contrast the underlying disease networks and pathological mechanisms of monogenic as opposed to complex retinopathies, using AMD as an example of the latter. We show that, surprisingly, genes associated with the different forms of retinopathies in general do not overlap despite their overlapping retinal phenotypes. Further, AMD risk genes participate in multiple networks with interaction partners that link to different ubiquitous pathways affecting general tissue integrity and homeostasis. Thus AMD most likely represents an endophenotype with differing underlying pathogenesis in different subjects. Localising these pathomechanisms and processes within and across different retinal anatomical compartments provides a novel representation of AMD that may be extended to complex disease in general. This approach may generate improved treatment options that target multiple processes with the aim of restoring tissue homeostasis and maintaining vision.This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 634479 (EYE-RISK). This work was supported by the Spanish Ministerio de Economía y Competitividad, Plan Nacional BIO2012-39754 and the European Fund for Regional Development. We acknowledge the support of the Spanish Ministry of Economy and Competitiveness, 'Centro de Excelencia Severo Ochoa 2013-2017′. We acknowledge the support of the CERCA Programme/Generalitat de Catalunya

Simple and complex retinal dystrophies are associated with profoundly different disease networks

Retinopathies are a group of monogenetic or complex retinal diseases associated with high unmet medical need. Monogenic disorders are caused by rare genetic variation and usually arise early in life. Other diseases, such as age-related macular degeneration (AMD), develop late in life and are considered to be of complex origin as they develop from a combination of genetic, ageing, environmental and lifestyle risk factors. Here, we contrast the underlying disease networks and pathological mechanisms of monogenic as opposed to complex retinopathies, using AMD as an example of the latter. We show that, surprisingly, genes associated with the different forms of retinopathies in general do not overlap despite their overlapping retinal phenotypes. Further, AMD risk genes participate in multiple networks with interaction partners that link to different ubiquitous pathways affecting general tissue integrity and homeostasis. Thus AMD most likely represents an endophenotype with differing underlying pathogenesis in different subjects. Localising these pathomechanisms and processes within and across different retinal anatomical compartments provides a novel representation of AMD that may be extended to complex disease in general. This approach may generate improved treatment options that target multiple processes with the aim of restoring tissue homeostasis and maintaining vision.This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 634479 (EYE-RISK). This work was supported by the Spanish Ministerio de Economía y Competitividad, Plan Nacional BIO2012-39754 and the European Fund for Regional Development. We acknowledge the support of the Spanish Ministry of Economy and Competitiveness, 'Centro de Excelencia Severo Ochoa 2013-2017′. We acknowledge the support of the CERCA Programme/Generalitat de Catalunya

An efficient siRNA-mediated gene silencing in primary human monocytes, dendritic cells and macrophages

International audienc

Bacterial expression of a designed single-chain IL-10 prevents severe lung inflammation

Interleukin-10 (IL-10) is an anti-inflammatory cytokine that is active as a swapped domain dimer and is used in bacterial therapy of gut inflammation. IL-10 can be used as treatment of a wide range of pulmonary diseases. Here we have developed a non-pathogenic chassis (CV8) of the human lung bacterium Mycoplasma pneumoniae (MPN) to treat lung diseases. We find that IL-10 expression by MPN has a limited impact on the lung inflammatory response in mice. To solve these issues, we rationally designed a single-chain IL-10 (SC-IL10) with or without surface mutations, using our protein design software (ModelX and FoldX). As compared to the IL-10 WT, the designed SC-IL10 molecules increase the effective expression in MPN four-fold, and the activity in mouse and human cell lines between 10 and 60 times, depending on the cell line. The SC-IL10 molecules expressed in the mouse lung by CV8 in vivo have a powerful anti-inflammatory effect on Pseudomonas aeruginosa lung infection. This rational design strategy could be used to other molecules with immunomodulatory properties used in bacterial therapy.This work has been supported by the European Research Council (ERC) grant agreement 670216 (MYCOCHASSIS). We also acknowledge the support of the Spanish Ministry of Economy, Industry and Competitiveness (MEIC) to the EMBL partnership, the Centro de Excelencia Severo Ochoa, the CERCA Program from the Generalitat de Catalunya, the European Union's Horizon 2020 research and innovation programme under grant agreement 634942 (MycoSynVac). ML-S acknowledges the support of the FEDER project from Instituto Carlos III (ISCIII, Acción Estratégica en Salud 2016; reference CP16/00094). We also acknowledge the staff of CRG/UPF Proteomics Unit who is part of the Spanish Infrastructure for Omics Technologies (ICTS OmicsTech) unit and is a member of the ProteoRed PRB3 consortium which is supported by grant PT17/0019 of the PE I + D + i 2013–2016 from the Instituto de Salud Carlos III (ISCIII) and ERDF