Cryptococcus neoformans is a pathogenic yeasts that infect mostly immunocompromised people. The strain H99 belongs to the C. neoformans variety grubii group. This is the reference strain that have already been sequenced. A project initiated by the Broad Institute aims at analysing the genome of about 300 clinical isolates including 28 of our French isolates. Part of our French isolates have been screened in terms of interaction with macrophages (774). Huge variations in terms of phagocytosis and intracellular proliferation of the yeasts were observed between clinical isolates (Alanio et al. mBio 2011). Thirteen of these clinical isolates together with H99 were studied in terms of transcriptome (using RNASeq). This work was performed by MA Dillies at the PF2. We correlated the expression of about 150 genes with the phenotype of the 13 clinical isolates and H99.

In the context of the swiss consortion InfectX (www.infectx.ch), we performed siRNA and drug screens to investigate the invasion of host cells by the bacterial pathogen Listeria monocytogenes. As a primary readout for infection we detected by fluorescence microscopy the presence of the bacterially-secreted protein InlC, which accumulates in the cytoplasm of infected cells (Kühbacher et al. 2013). A first manuscript concerning the analysis of a kinome-wide siRNA library and a drug library has been published recently (Rämö et al. 2014) and the analysis of a genome-wide siRNA screen has been submitted for publication (Kühbacher et al. In Revision), in which major signaling pathways subverted by L. monocytogenes are identified. However, besides the presence of InlC, many other features have been measured in infected cells including InlC intensity, bacterial distribution in host cells, actin morphology and distribution, cellular replication state, cellular context of infected cells, etc. We intend to analyze the full set of measured parameters in order to identify global signaling cascades subverted by L. monocytogenes for infection or used by the cell to control bacterial proliferation.

Cell surface protein signatures have been successful to discriminate hematopoietic progenitor populations allowing major advances in understanding blood cell production, to define pathways in hematologic malignancies and to foster new therapeutic approaches. Limited knowledge on the phenotype of cells that participate in heart formation impairs our understanding of progenitors of the cardiac cell lineages and their eventual persistence in the adult organ. As a consequence, therapies to restore heart function after injury have been unsuccessful. A number of membrane proteins have been identified on cardiomyocytes; on cardiac fibroblasts; and on endothelial cells, however a multi-parametric analysis of the phenotype of the different cardiac cell compartments along development is still missing. We combined multi-parametric flow cytometry with transcriptional characterization, based on well-known gene expression patterns, to describe major cardiac cell-subsets. The expression of CD24, CD54, Sca-1 and CD90 allowed defining cardiac populations in the non-hematopoietic and non-endothelial cell fraction by flow cytometry. Transcriptional profiling of the sorted populations enabled the identification of cardiomyocytes, in the CD24+ population, while differential expression of CD54, Sca-1 and CD90 defined four cardiac stromal compartments. The identified subsets exhibited specific distributions in three analyzed regions (atria, auriculo-ventricular junction and ventricles). We have thus identified a panel of surface markers, some of which novel in the cardiac context, that allowed assigning surface signatures to different cellular fractions by their unique transcriptional profiles. This work is the foundation for comprehensive studies on the role of different cell fractions by their unique transcriptional profiles.

Stem cells are defined by their is their capacity for self-renewal and differentiation. Some adult tissues maintain a reservoir of stem cells, that generally reside within specialized microenvironments, known as stem cell niches, that regulate their behaviour. Skeletal muscle stem (satellite) cells are quiescent in homeostatic conditions in adults, and they are activated after muscle injury, when they re-enter the cell cycle, proliferate and differentiate into myoblasts, which will then fuse to form new muscle fibers. Satellite cells express the paired/homeodomain gene Pax7, which plays a critical role in satellite cell maintenance postnatally. Numerous experiments have shown that the skeletal muscle stem cell population is heterogeneous, therefore like many other stem cell systems, characterising the stem cell states is a major objective. In our laboratory, a reversible dormant cell state was identified, correspondent to a Pax7Hi quiescent subpopulation (top 10% of the Pax7-nGFP+ cells isolated from the transgenic mouse model Tg:Pax7-nGFP) with a lower metabolic activity and longer lag for the first cell division compared to Pax7Lo cells [1]. Muscle stem cells that survive for extended periods post-mortem are also dormant, suggesting that this property, in addition to anoxia [2] contributes to their viability. Therefore, different physiological states are associated with distinct cell states of muscle stem cells. Metabolism could play a critical role in dictating whether a cell remains quiescent, proliferates or differentiates. Stem cell metabolic plasticity in homeostasis and differentiation, as well as during cell reprogramming, is well described in different cell systems. However, unanswered questions remain regarding the metabolic regulation of satellite cell biology and skeletal muscle regeneration. In this project, we will investigate the behaviour of muscle stem cells in distinct physiological states, especially post-mortem and aging.

The PIBnet initiative is a joint effort by the above laboratories to modernize their activities, including collection management and microbial characterization approaches and technologies. Within this large concerted effort, a priority is to promote WGS as the major characterization approach of microbial agents for surveillance and outbreak investigation. Our ambition is to have shifted to WGS as a routine strain characterization method for epidemiological surveillance and outbreak investigation in the Institut Pasteur NRCs at the end of 2016. The target volume is 10 000 genomes a year. On the bioinformatics level, this requires implementing (1) fast data treatment tools and (2) Genotyping/classification schemes and methods to extract medically relevant information from genomic sequences (resistome, virulome).

HIV-1 replication requires the integration of the viral genome into the cell genome. A viral-encoded enzyme, integrase (IN), performs this critical step of infection and is a promising target for anti-viral therapeutics. If the catalytic properties of INs are well characterized, the mechanisms responsible for their site selectivity are still under investigation. Several cellular proteins, such as the LEDFGF/p75 transcription co-activator, the RNA polymerase II machinery, nuclear pore proteins and specific modified histones have been proposed to be involved in IN selectivity at a genomic level but the underlying molecular mechanisms remain to be demonstrated. In addition, structural parameters of the target DNA helix (curvature, flexibility, topology) are proposed to regulate IN selectivity at a local level. Our aims are to study the role of these different parameters of IN selectivity, using both in vitro and in vivo approaches. In vitro, we will map integration sites on various target DNA substrates (naked DNA or chromatin, minicircles, plasmids with different topologies, transcribed templates) and will test the effect of purified proteins suspected to regulate IN selectivity. In vivo, integration sites will be mapped in cells depleted of these suspected regulators or in cells incubated with drugs targeting enzymes involved in transcription, DNA topology or histone modifications. Integration sites will be mapped using published or “home-made” protocols and the sites will be compared with DNA structural parameters, nucleosome positions, histone modifications or transcriptional parameters (published maps). Bio-informatics tools are crucial for these correlative and statistical analyses of integration sites. Our project relies on complementary in vivo, in vitro and in silico approaches. It should establish molecular and mechanistic rules of HIV-1 integration selectivity that could serve in the development of new antiviral strategies and of safer gene therapy vectors.

Grâce à la plateforme PF2 à Pasteur, nous avons réalisé une étude de microarray ( Affymetrix Genechip Mouse Gene 2.0 ST Array) avec les fibroblastes de souris. Pourriez vous SVP nous aider à analyser ces données?

Molecular markers of cervix lesions linked to HPV infections.

Les cyanobactéries sont des microorganismes qui prolifèrent dans de nombreux plans d’eau et perturbent leurs fonctionnements et leurs usages car elles sont capables de produire des toxines dangereuses pour la santé humaine et animale. Si la réglementation sanitaire est basée, pour l’instant, sur la surveillance d’une seule toxine, il est désormais connu que ces microorganismes sont capables d’en synthétiser un grand nombre qu’il conviendrait de mieux prendre en compte dans le futur. C’est pourquoi, dans le but de mieux connaître le potentiel toxique des cyanobactéries, ma thèse s'applique, par des études sur leur génome et par une approche de chimie, à caractériser les gènes impliqués dans la synthèse de ces métabolites ainsi que les métabolites produits par ces gènes, à déterminer sur des souches de culture et dans des échantillons naturels provenant de plans d’eau d’Ile de France quel est le potentiel de production de ces métabolites et à mieux comprendre les facteurs environnementaux qui favorisent cette production. Deux équipes de Paris (Pasteur et iEES) sont associées sur ce travail qui implique également des collaborations étrangères. S'il est désormais bien connu qu'une part importante du métabolisme des cyanobactéries qui sont des microorganismes photosynthétiques, est régulée en fonction des phases de lumière et d'obscurité, les connaissances disponibles sur la synthèse des métabolites secondaires sont en revanche beaucoup plus limitées. Ces métabolites ont pourtant un double intérêt puisque certains sont toxiques pour l'Homme alors que d'autres ont un intérêt pharmaceutique potentiel. Leur synthèse repose sur l'expression de clusters de gènes pouvant être de très grande taille (jusqu’à 100 kb par région).

The PIBnet initiative is a joint effort by 15 National Reference Centers (NRC), 8 Collaborative Centers of World Health Organization, the Collection de l’Institut Pasteur & Cyanobacteria collection and the CIBU to modernize their activities, including collection management and microbial characterization approaches and technologies. Within this large concerted effort, a priority is to promote whole genome sequencing (WGS) as the major characterization approach of microbial agents for surveillance and outbreak investigation.   Our ambition is to have shifted to WGS as a routine strain characterization method for epidemiological surveillance and outbreak investigation in the Institut Pasteur at the end of 2016. The target volume is 10,000 genomes a year. On the bioinformatics level, this requires implementing fast data treatment tools, databases, genotyping schemes and methods to extract medically relevant information from genomic sequences (resistome, virulome).

Human macrophages are the main cell target of Mycobacterium tuberculosis (Mtb), the etiologic agent of tuberculosis. Once phagocytosed, bacilli escape bactericidal functions of macrophages and they multiply inside the cell. Understanding interactions between bacilli and human phagocytes is primordial to develop new strategies to combat tuberculosis. We propose a project aiming at deciphering cell-cell communications between infected cells and non-infected cells. We will use the transcriptomic and the proteomic approaches to discriminate the global response of these differents sub-populations. To our knowledge, this work represents the first study that combines two different levels for the identification of a specific response of infected-cells and neighboring non-infected cells. This study would determine cellular markers of a Mtb signature.

Cryptococcus neoformans is a sugar-coated yeast that is able to interact closely with numerous organisms in the environment including amebae, paramecium of nematodes. The interaction with these organisms probably shaped its virulence. The ability to survive nutrient starvation, oxidative stress, desiccation, both in the environment and in humans, indicates a high level of physiological and metabolic plasticity of the yeast. In humans, after primary infection during childhood, the yeast is able to survive within the host for years before reactivation, leading to a deadly disseminated fungal infection. This phenomenon, called dormancy / quiescence is one of the main biological features of this fungus in relation with disease pathogenesis. It is known in bacteria, parasites and other fungi. There is no consensus on the definition of dormancy. Most often, dormant cells are characterized by a low metabolic activity sometimes undetectable under normal laboratory conditions and the ability to be resuscitated by adequate stimuli. In C. neoformans, dormancy has only been demonstrated epidemiologically in our laboratory but not experimentally so far. We developed an assay where yeasts cells exhibiting characteristics of potentially dormant cells were generated. Our current project aims at exploring the conditions leading to, the biology of the entry in and the mechanisms sustaining dormancy.

Collect statistics on variants found in different strains of influenza virus. Determine variant effects to the protein sequence.

An experiment of RNAseq was performed in triplicate with the strain A of Clostridium tetani in TGY (low production of toxin) and MS (high production of toxin) at 24 and 48 h of culture.  This RNAseq was performed in the Pasteur platform PF2. Different comparisons were performed: MS-48h vs MS-24h, TGY-48h vs TGY-24h, TGY-24h vs MS-24h and TGY-48h vs MS-48h. Excel files with differentially expressed genes were provided. For each comparison there are three excel files: complete.xls (contains results for all features), up.xls (contain results for significantly up-regulated features. Features are ordered from de most significant adjusted p-value to the less significant one) and down.xls  (contain results for significantly down-regulated features. Features are ordered from de most significant adjusted p-value to the less significant one). We would like to perform GO term enrichment analysis on the set of genes showing differential expression patterns in the considered contrasts. State of art tools to identify functional enrichments (e.g. DAVID knowledge) do not recognize Clostridium tetani protein and gene identifiers. One possibility is that such tools do not include Clostridium tetani entries in their databases.  The aim of this project is to develop an alternative approach to carry out the functional enrichment analysis on the differentially expressed genes.

Analysis of the immune response to yellow fever 17D vaccination

Aim : In vitro infection of innate immune cells by L. amazonensis (L.am.) seems to be associated to an increase in resistance to cell death of infected cells. This project aims at deciphering the impact of in vitro L. amazonensis (L.am.) amastigotes infection on cell death processes including apoptosis, autophagy, pyroptosis and necroptosis in different host cells, i.e. Bone-marrow- derived macrophages (BMDMs) and dendritic cells (BMDCs) after one day of infection. Material : RNA samples were obtained from control and infected BMDMs (BALB/c mice) or BMDCs (BALB/c, C57BL/6 and DBA/2 mice) after their sorting by Fluorescence Activated- Cell sorting. For BALB/c BMDCs, amastigotes were also added to cells in presence of immune serum to trigger their opsonization. Samples were analysed a few years ago at the « Plateforme Transcriptome et Epigénome » with the Affymetrix technology. RNAs from BMDMs and BMDCs were analysed with the Affymetrix Mouse430_2 GeneChips and the Affymetrix Mouse Gene ST 1.0 arrays respectively.  

The objective of this study is to evaluate how the different programming of distinct CD4+ T cell subsets affected their susceptibility to HIV infection and the survival of infected cells. Dr. Saez-Cirion's Team evaluates how the metabolic state of CD4⁺ T cells and the regulation of cellular factors shape the distribution of the HIV reservoir in distinct CD4⁺ T cell subset. This project uses new technologies and reagents to analyze cells from uninfected donors, and from HIV patients in acute infection, chronic infection and HIV remission.

The Transcriptome & Epigenome Platform is dedicated to the development and use of high throughput approaches for transcriptomics and epigenomics studies. The platform is accessible to any research team from the Pasteur Institute (80% of the projects) as well as from outside. It is involved (most often as collaborator) in several projects funded by the ANR, AVIESAN and by the Pasteur Institute in the framework of the PTR programs. Next Generation Sequencing (NGS) based on the Illumina technology (HiSeq 2000/2500 sequencers) is used to perform RNA-sequencing experiments for which a large amount of data is generated. After a first step involving bioinformatics, specific statistical methods must be used be analyze rigorously the data. These analyses are most often performed by the statistician(s) of the platform. They are also in charge of bibliographical survey activity.

The Transcriptome & Epigenome Platform is dedicated to the development and use of high throughput approaches for transcriptomics and epigenomics studies. The platform is accessible to any research team from the Pasteur Institute (80% of the projects) as well as from outside. It is involved (most often as collaborator) in several projects funded by the ANR, Microbes and Brain, ERANET and by the Pasteur Institute in the framework of the PTR programs. Next Generation Sequencing (NGS) based on the Illumina technology (HiSeq 2000/2500 sequencers) is used to perform RNA-sequencing experiments for which a large amount of data is generated. After a first step involving bioinformatics, specific statistical methods must be used be analyze rigorously the data. These analyses are most often performed by the statistician(s) of the platform. They are also in charge of bibliographical survey activity.

  Shigella is an enteroinvasive bacterium that induces bacillary dysentery. It invades human intestinal epithelial cells causing the inflammatory destruction of the colonic epithelium. Our previous work reported that Shigella inhibits the secretion of its host cell (Mounier et al Cell Host Microbes 2012) via several virulent proteins injected by the bacterium such as IpaJ and VirA. These two effectors may have redundant action. Thus, to address the effect of Shigella on the secretome of its host cell and in particular define the precise action of IpaJ and VirA, we conducted a mass spectrometry (MS) analysis on apical (A) and basal (B) secretion of polarized infected human intestinal cells using several strains: wild type (WT), avirulent strain (mxiD) and mutated strains either on virA, ipaJ or both (virAipaJ) and compared to non-infected cells (NI). We have in total 6 infection conditions and we collected apical and basal secretion medium (total 12 MS data). Most of the conditions were done in triplicate. We have now these quantitative MS data (excel file) that gave between 300 (basal secretion) to 1000 proteins (apical secretion) secreted differently among the different conditions. We need your collaboration to analyze our data to: Check whether our protein candidates are in databases of secreted factors Obtain protein clusters of our hits among the 6 conditions used (12 datasets)

assess the faisability of the chip analysis to our samples from laser capture microdissection of the mouse intestine, of diverse quality and preparation levels

Project context and summary : Cryptococcus neoformans is a sugar-coated yeast that is able to interact closely with numerous organisms in the environment including amebae, paramecium of nematodes. The interaction with these organisms probably shaped its virulence. The ability to survive nutrient starvation, oxidative stress, desiccation, both in the environment and in humans, indicates a high level of physiological and metabolic plasticity of the yeast. In humans, after primary infection during childhood, the yeast is able to survive within the host for years before reactivation, leading to a deadly disseminated fungal infection. This phenomenon, called dormancy / quiescence is one of the main biological features of this fungus in relation with disease pathogenesis. It is known in bacteria, parasites and other fungi. There is no consensus on the definition of dormancy. Most often, dormant cells are characterized by a low metabolic activity sometimes undetectable under normal laboratory conditions and the ability to be resuscitated by adequate stimuli. In C. neoformans, dormancy has only been demonstrated epidemiologically in our laboratory but not experimentally so far. We developed an assay where yeasts cells exhibiting characteristics of potentially dormant cells were generated. Our current project aims at exploring the conditions leading to, the biology of the entry in and the mechanisms sustaining dormancy.

Listeria monocytogenes is a gram-positive bacterium responsible for the food-borne disease listeriosis. This pathogen can invade and replicate in the cytoplasm of both macrophages and non-professional phagocytes. In order to better characterize the host response to Listeria, we are using microarrays to identify genes and cytokines up or downregulated during infection.

It has been found in the past that the peptidoglycan (PGN) degradation fragments DAP-containing muramyl tripeptide (M-triDAP) and muramyl di-peptide (MDP) stimulate innate immune receptors Nod1 and Nod2. However, it remains to be clarified how the fragments reach Nod1 and Nod2, since these receptors are intracellular. The aim of the project is thus to investigate novel factors in peptidoglycan signalling, using gene trap mutagenesis in human near-haploid cells to randomly knock out genes and do a genome wide screen to establish a library. There is a pressing need to find novel therapeutic strategies, and it has been shown in the past that the above described technique of finding genes works well for this (see Carrette et al., 2011). Results will be validated in relevant mouse models and epithelial cell lines using CRISPR-Cas.

Integration of the viral reverse-transcribed genome into the genome of infected cells is an essential step of retroviral replication and is performed by a viral-encoded enzyme, named integrase (IN). In the case of HIV-1, IN is a new and efficient anti-viral target. The selectivity of this enzyme for its cellular genomic sites is also a major parameter of HIV replication and is regulated by several cellular parameters. One of them is chromatin, and different levels of this nucleoprotein complex are involved in the regulation of IN selectivity. Using in vitro integration assays, established by our team and collaborators, we have studied this regulation at two levels of chromatin architecture: large poly-nucleosome templates (Botbol et al., 2008; Lesbats et al., 2011; Benleulmi et al., 2015; Naughtin et al., 2015) or nucleosome-induced DNA curvature mimicked by DNA minicircles (Pasi et al., 2016). Our present project is to study IN selectivity into mononucleosomes (MN). These MNs will be used as target substrates of integration and the role of MN structure, histone modifications and IN cofactors will be studied. Results obtained in vitro, will be confronted to structural data obtained by molecular modeling and to integration sites observed in infected cells. This project will benefit from our expertise in integration in chromatin templates and a previous collaboration with the C3BI on the analysis of integration sites (Pasi, M., Mornico, D., S. Volant, S., et al., 2016). This project is funded by the ANRS.

Over the last years, innate lymphoid cells (ILC) have been increasingly investigated. Despite the absence of antigen specific receptors, they belong to the lymphoid lineage and represent important sentinels for tissue homeostasis and inflammation. They contribute to numerous homeostatic and pathophysiological situations via specific cytokine production. ILC are currently divided into three groups based on the expression of specific transcription factors and secretion of cytokines. We focus this study on fetal ILC3 development. We have observed that contrary to lymphocytes, ILC can migrate toward lymphoid organs, tissues and mucosal sites as lymphoid precusors and terminate their developmental program in situ. In the fetal spleen, we observe different stages of ILC3 with precursors that are already RORgt+ but could still give rise to other ILC fate. Hence, these splenic ILC3 precursors were sorted and analyzed by microarrays. The identification of gene expression differences was used to design a single cell transcriptomic assay. The single cell transcriptomic assay is based on this specific selection of primers for transcription factors and cytokine receptors. We evaluate their differential expression in single cells at different stages of their plasticity. The aim is to decipher the progression from an ILC precursor stage to an another in one cell. We are also using the new polaris technology to detect and evaluate at different early timepoints the sequence of molecular events for changing ILC cell fate. In this case, we chose to use the sc RNAseq technology. The single cell transcriptomic will be analyzed and bioinformatic programs will be applied in order to organize the sequential molecular events and to build a hierarchical developmental model in case of ILC cell fate decisions.

Our recent analyses suggest that the genetic determinants of human neuroanatomical diversity are massively polygenic. Like other quantitative traits such as height – but also IQ or ASD risk – neuroanatomical diversity seems to result from the aggregated effect of thousands of frequent variants, each of small effect. GWAS should then require populations of hundreds of thousands of individuals to start to detect the individual variants. GCTA (genomic complex trait analysis) offers an alternative approach to obtain valuable neurogenetic information despite the current impossibility to detect enough individual variants to explaining any substantial part of the variability. We are currently pooling together neuroimaging genomics data from multiple international projects (in particular, IMAGEN, ENIGMA, UK Biobank) to replicate and extend our earlier analyses. We aim to: (1) Compute the amount of variance captured by genome-wide SNPs (SNP-heritability) for the several brain regions: ICV, BV, Hip, Th, Ca, Pa, Pu, Amy and Acc, (2) Compute the matrix of SNP-based genetic correlation among structures, (3) Partition the variance captured by SNPs among structural and functional sets: per chromosome, genic vs non-genic, low/medium/high minor-allele frequency, positive/negative selection, involved or not in neurodevelopment, etc. (4) Compare our results with those obtained using GWAS-based estimations (for example, those used in ENIGMA2). GCTA requires the computation of matrices of genetic relationship among all individuals, and thus, direct access to the genotyping data. Once the matrices are computed, the genotyping data is no longer required, and it is not possible to reconstruct an individual's genome from the matrices. Our analysis of the IMAGEN cohort was based on 1,765 Individuals, which gave us sufficient statistical power (80%) to detect only strong heritabilities (h2~45%), and the estimations had very large standard errors (~20%). A cohort of 4,000 subjects should allow us to decrease the standard error to ~8% (80% power to detect h2=22%), and a cohort of 8,000 subjects should decrease it to ~4% (80% power to detect h2=11%). In this way, we could obtain more accurate estimates, but also detect eventually more subtle effects related to functional genomic partitions.   References Yang et al (2010) Common SNPs explain a large proportion of heritability for human height. Nature Genetics, doi: 10.1038/ng.608 Davies et al (2011) Genome-wide association studies establish that human intelligence is highly heritable and polygenic. Molecular Psychiatry, doi: 10.1038/mp.2011.85 Gaugler et al (2014) Most genetic risk for autism resides with common variation. Nature Genetics, doi: 10.1038/ng.3039 Wood et al (2014) Defining the role of common variation in the genomic and biological architecture of adult human height, doi: 10.1038/ng.3097

After the behavioural characterisation of the Shank3 KO cohort, we extracted and dissected different region of the brain: cortex, hippocampus, striatum, cerebellum.

These regions were selected according to the expression level of Shank3 (Peça et al. 2011). Using QUIAGEN miRNAeasy with DNAse, miRNA-enriched RNA was extracted from the brain regions in order to perform RNAseq.

We will ask 3 questions:

• What is the pattern of Shank3 isoforms in different brain regions?

• What are the genes/pathways differentially expressed in wild-type and Shank3 knock-out mice?

• What are the genes/pathways associated with the severity of the self grooming behaviour ?

Beside data driven eperiments, we will test candidate genes/pathways such as glutamatergic receptors and <

See below  

Nous avons créer un programme sous R pur l'analyse non supervisé de fichier de cytométrie et nous avons besoin d'aide pour optimiser ce programme. Nous avons également besoin de conseils pour optimiser le clustering. Nous avons déjà rencontré Hugo Varet.

In recent years, large genome-wide association studies (GWAS) have been successful in identifying thousands of significant genetic associations for multiple traits and diseases1. In the course of this endeavor, sample size has proven to be the key factor for identifying new variants. For example, GWAS of body mass index (BMI), now including up to 350,000 individuals from more than 100 cohorts, have been able to identify genetic variant that explain as low as 0.02% of BMI variance2. While standard approaches for detecting new genetic variants associated with traits and diseases will go on as sample size increases, multivariate analyses have been proposed as an alternative strategy for both improving detection of new variants and exploring the multidimensional components of complex traits and diseases. Intuitively, multivariate analysis can be used to improve detection of variants displaying a pleiotropic effect3 by accumulating moderate evidence of association across multiple traits and diseases. Several recent examples have been published about not only GWAS hit overlap across related traits4, but also of genome-wide shared genetic effect5. Multivariate analyses of GWAS have also proven useful to understand shared genetics between diseases5, and potential causal relationship between phenotypes using Mendelian randomization (MR)6. Importantly, most of existing multivariate methods are based on GWAS summary statistics, while approaches based on individual-level data have been seldom considered because of major practical and ethical issues. In the continuity of ongoing work on multi-phenotype analysis (Aschard et al 20147, Aschard et al 20158), we developed an effective and robust multivariate approach of GWAS summary statistics that addresses the major barriers of existing approaches, i.e. the presence of correlation between studies that would exists when GWAS analyzed share sample9-16. Our approach consists in a robust omnibus multivariate test of GWAS summary statis

Nous avons pu montrer grâce au projet de recherche clinique VOYAG’R (PHRC AOR 11101- IP Pr S. Matheron) que les voyages dans une zone tropicale constituaient un risque d’acquérir une Entérobactérie multi-résistante (EMR). Pendant 15 mois, la présence d’EMR a été recherchée chez 574 sujets avant et après leur voyage en zone tropicale. Les voyageurs porteurs au retour étaient suivis sur une période de 12 mois (1, 2, 3, 6 et 12 mois ou jusqu’à négativation). Au cours de leur séjour, la moitié des voyageurs ont acquis une EMR. Nous avons également observé que trois mois après leur retour, 95% des voyageurs avaient éliminé leur EMR. Cependant 11 sujets ont conservé leur(s) souche(s) d’EMR pendant au moins 6 mois. Ces souches persistantes pourraient avoir des capacités pour perdurer au sein du tube digestif

Statistical analysis of PI survey for the scientific direction

Background: Dyslexia is characterized by difficulty with learning to read fluently and with accurate comprehension despite normal intelligence. It affects 5–10% of school-age children. Familial studies repeatedly showed that first-degree relatives of affected individuals have a 30–50% risk of developing the disorder. Twin studies showed that heritability was approximately 50% with a higher concordance rate for monozygotic twins compared to dizygotic twins. Although genetic factors contribute to dyslexia, very little is known on the genes associated with the condition. Preliminary data: Our project consists in the complementary analysis of (i) a cohort of 209 patients with dyslexia, 89 relatives and 95 very well phenotyped controls and (ii) an extended pedigree (Nantaise family) with 12 members diagnosed with dyslexia in three generations. For all the individuals of the project, we genotyped >600K SNPs in order to detect SNP association and copy-number variants (CNVs). For the extended pedigree, we also used linkage analysis and whole genome sequence (WGS). Our preliminary results indicate that a single region on chromosome 7q36 is segregating with dyslexia in the Nantaise family. The region is located within CNTNAP2, a gene previously proposed as a susceptibility gene, but without formal proof of its association. The WGS data of three affected and three unaffected individuals of the pedigree was performed to detect all the variants in the linkage region. Project: We proposed to use this unique resource in France to characterize the genetic profile of patients with dyslexia. We will (i) detect the CNVs present in the patients and (ii) detect the variants in the linkage region.

Mood disorders such as bipolar and major depressive disorders affects 2-5% of the population worldwide. They are relapsing, major psychiatric illnesses with poorly understood neurobiology, typically incomplete treatment responses, and often unsatisfactory clinical outcomes, with a high risk of premature mortality due to suicide and clinical comorbidities. Its complex manifestations include marked disturbances of emotional regulation, sensory-perception as well as major changes in mood, thinking, and many aspects of behavior. It is of crucial importance to be able to discriminate mood states in clinical practice, as pharmacological and psychological treatments as well as course of illness and outcome differ across the different mood states. By applying advanced mathematical approaches (with statistical/computational advice from a C3BI’s colleagues) this study aims to explore how sociodemographic, psychosocial and behavioral predictors may contribute for better characterizing patients with mood disorders. The study also aims to identify biological predictors of different mood states as well as of treatment response in mood disorders. Having a deeper understanding of phenomenology and pathophysiological mechanisms of mood disorders may help clinicians to provide more personalized interventions for individuals at-risk or suffering from mood disorders.

Blood cells were collected in the field from patients admited in the Ebola treatment center of Macenta (Guinea). After red cells lysis, blood cells were frozen and RNA was extracted after the shipment of samples in France. Despite poor RNA quality, Affimetrix chips have been performed and transcriptomic data are available. The aim of this study is to compare the transcriptomic data from patients who survived and those who died and also to perform a kinetic analysis of the infection in the two groups of patients.  Samples from febrile patients who were not infected with Ebola virus have been used as negative controls.

Molecular markers of cervix lesions linked to HPV infections.

Innate lymphoid cells (ILCs) are the most recently identified components of the innate immune system. ILCs colonize different tissue sites and react promptly to microenvironmental perturbations. Due to their high plasticity, ILCs can shape their functional output in response to local cues. As such, ILCs play roles under homeostatic conditions and in the context of infection, chronic inflammation, metabolic diseases and cancer. Diverse ILC subsets (NK cells, ILC2) have been shown to regulate the metabolic homeostasis. Metabolic states affect cellular functions and have been shown to play an important role in the regulation of adaptive immunity. In contrast, almost nothing is known about innate lymphocytes metabolism and the importance of energy regulation for ILC function. This project will study metabolic profiles in human ILC subsets under diverse environmental conditions. Enhancing or interfering with ILC activity could ultimately represent a novel useful therapy for chronic inflammatory diseases.

Lyme borreliosis is the most common tick-borne disease in the northern hemisphere. In Europe, it is transmitted by Ixodes ticks that carries bacteria belonging to the Borrelia burgdorferi sensu lato complex. Our study was focused on peri-urban forests of Île-de-France. These forests are frequented by many visitors and the risk of exposure to tick bites is high. One of them, the Sénart forest, is located 30 km south of Paris (in the Île-de-France region) and has a large number of visitors (3 million per year in the late 1990s). This forest has the characteristics of being partly invaded by chipmunks (Tamias sibiricus). The chipmunk has been introduced from Eurasia, particularly Siberia, China and Korea. The first individuals were released by their owners at the western end of the Sénart forest, in the 1970s. The northeastern part of the forest was colonized recently. Our current study aims to evaluate the evolution of the infection of Ixodes ricinus by Borrelia burgdorferi sl. by comparing the results obtained during 3 years and to determine the consequences of the proliferation of this non-native rodent species, Tamias sibiricus, on the risk of transmission of Lyme borreliosis. For this purpose, we analyzed the rate of infection and the density of infected ticks during 2008, 2009 and 2011 in several locations of the Sénart forest. These results were compared to those obtained for ticks collected in 2009 in two other peri-urban forests of Île-de-France (Rambouillet and Notre-Dame) that have not yet been colonized by these rodents. The density of nymphs, adults as well as the infected density of nymphs and adults were compared according to several factors: location of tick collection in the forest,  presence or absence of chipmunks, type of vegetation, temperature and humidity.

Autism Spectrum Disorders (ASD) are heterogeneous neurodevelopmental disorders with a complex genetic architecture. They are characterized by impaired social communication, stereotyped behaviors and restricted interests and are frequently associated with comorbidities such as intellectual disability, epilepsy and severe sleep disorders. Hyperserotonemia and low melatonin levels are among the most replicated endophenotypes reported in ASD, but the genetic causes of such alterations remain largely unknown. Based on the biochemical profile of 717 individuals including 213 children with ASD, 128 unaffected siblings and 376 parents and other relatives, we aim to estimate the heritability of five quantitative traits associated with the melatonin synthesis pathway: whole-blood serotonin, platelet N-acetylserotonin (NAS) and plasma melatonin levels, as well as the two enzymes AANAT and ASMT activity measured in platelets.

Rationnel. Le mode de présentation clinique du sepsis est très polymorphe. Chez les patients septiques consultants dans les services des urgences, la présence d’une hyperthermie ou d’autres critères du syndrome de réponse inflammatoire systémique (SIRS) n’est pas suffisante pour aider au diagnostic de sepsis. De nombreux efforts de recherche ont abouti à la proposition d’innombrables biomarqueurs de sepsis essentiellement étudiés en soins intensifs. Même si certains, comme la procalcitonine (PCT) ont atteint un relativement bon degré de prédiction aux urgences, leur usage en routine demeure controversé. Compte tenu de la physiopathologie complexe du sepsis, une approche combinatoire pourrait permettre d’atteindre des performances difficilement envisageables avec un biomarqueur seul. Objectif primaire. Etudier les performances statistiques d’un panel de biomarqueurs d’intérêt, individuellement et en association, pour le diagnostic de sepsis aux urgences. Objectifs secondaires. Etudier les performances statistiques d’un panel de biomarqueurs d’intérêt, individuellement et en association, pour le diagnostic d’état septique grave (sepsis sévère et choc septique) et la stratification du risque (prédiction de l’admission en soins intensifs et/ou du décès). Type d’étude. Etude de cohorte monocentrique prospective non-interventionnelle Patients et critères d’inclusion. 300 patients consultant dans le service des urgences ayant une suspicion de sepsis + 30 sujets sains. Critères de non inclusion. Patient mineur de moins de 18 ans, femme enceinte, conditions de vie rendant impossible le suivi à 28 jours, refus de participer à l’étude. Mesures. Pour chaque patient, lors du bilan sanguin initial, prélèvement de 3 tubes pour le dosage a posteriori d’un panel de biomarqueurs d’intérêt explorant les différentes voies biologiques activées au cours du sepsis.  

Chronic inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease, spondyloarthritis (SpA) and psoriasis cause significant morbidity and are a substantial burden for the affected individuals and the society. An important obstacle to early diagnosis and the development of more specific and effective therapies is the very limited understanding of the pathogenesis of these diseases. In the past years genome-wide association studies have identified many genes that were not known to be involved in pathogenesis, and have linked several genes in immune pathways to inflammatory diseases, indicating that the immune system plays an essential role in the pathogenesis of these diseases. The current challenge is to correlate these genetic variants with the effector mechanisms implicated in pathogenesis, to allow translation of the genetic data into relevant diagnostics and innovative treatment strategies. To meet this challenge, we have designed a clinical study that examines the immune signaling pathways, the transcriptional networks and the genotype in the same SpA patient, in order to establish a link between genetic variation, cellular phenotype and function, and pathology. This approach will advance our understanding of the pathogenic mechanisms, and identify novel and relevant diagnostic tools, therapeutic targets and biomarkers. The long-term outcome of this strategy will be the rational design of specific therapies tailored to the genotype of the patient.

The interferon-induced transmembrane (IFITM) proteins protect cells from diverse virus infections, including Influenza, HIV and Zika viruses, by inhibiting virus-cell fusion. We showed that IFITM proteins act additively in both productively infected cells and uninfected target cells to inhibit HIV-1 spread, potentially conferring these proteins with greater breadth and potency against enveloped viruses. We also reported that amino-terminal mutants of IFITM3 preventing ubiquitination or endocytosis are more abundantly incorporated into virions and exhibit enhanced inhibition of HIV-1 fusion. An analysis of primate genomes revealed that IFITM3 is the most ancient antiviral family member of the IFITM locus and has undergone a repeated duplication in independent host lineages. Some IFITM3 genes in nonhuman primates, including those that arose following gene duplication, carry amino-terminal mutations that modify protein localization and function. Our aim is to analyze the RNA levels of the various members of the IFITM family, in various normal or pathological human or animal tissues.

It has been shown that methylation can act as a kind of memory of the immune system. For patients with co-infections, it is of particular importance to know when to begin an anti-retroviral therapy, especially if they are already infected with tuberculosis. The goal of this study is to find hyper or hypo methylated loci related to the reaction of HIV patients (co-infected or not) to different kind of treatments.

Objectives: Our objective was, through whole genome sequencing, to establish a comprehensive repertoire of the non-synonymous polymorphisms (natural polymorphisms and/or mutations of resistance) in genes involved in resistance to azoles and echinocandins. Methods: Two collections of C. albicans clinical isolates were used. The first one consists of 151 epidemiologically-unrelated strains susceptible to antifungal agents. The second one consists of 9 isolates resistant to fluconazole and 1 to fluconazole and caspofungin. The whole genome sequencing was performed on an Illumina HiSeq 2000, generating 100 bp reads (roughly 100X coverage on average). The reads were mapped to the SC5314 reference genome (Assembly 22) using the BWA alignment tool. Then SNPs were detected by GATK and selected with the recommended filters. Using homemade scripts we analyzed the sequences of 5 genes involved in the resistance to azoles (ERG11, TAC1, MRR1 and UPC2) and echinocandins (FKS1) and compared them to the sequences of reference strain SC5314. Results: Among the 151 antifungal susceptible strains we identified 126 distinct natural amino-acid substitutions. Using this repertoire, we identified from the 10 resistant strains, 22 amino-acid substitutions in addition to some of the above-mentioned natural polymorphisms. Among them, 10 have already been associated to azoles or echinocandins resistance. The remaining 12 substitutions are novel putative azoles resistance mutations affecting ERG11 (n=4/11), TAC1 (n=6/7) and UPC2 (n=2/3).

Ataxia-telangiectasia (AT) is an autosomal recessive disorder characterized by a biallelic mutation of the Ataxia Telangiectasia Mutated (ATM) gene. The ATM protein is involved in a very large number of cellular functions (over 700 substrates), mainly DNA repair, cell cycle regulation, mitochondrial and oxidative metabolism, as well as regulation of gene expression. The majority of hematological malignancies occurring in AT patients are non-Hodgkin's B lymphomas and Hodgkin's lymphomas. The association with the Epstein-Barr virus (EBV) is found in 50 to 100% of these cases according to the histological subtype. EBV is a widespread virus in human populations with a prevalence greater than 90% and is associated with the development of lymphomas in immunocompromised patients. We will study the transcriptome of EBV-infected cells in ATM patients, in order to determine the impact of ATM on EBV infection control.

This project aims at identifying novel genetic traits that regulate the anti-tumor activities of NK cells and homeostasis of NK cells and other ILC using an unique mouse resource, the Collaborative Cross (CC). CC is a panel of recombinant inbred mice derived from randomized breeding of eight laboratory inbred strains combining high genetic diversity with the advantage of inbred mouse strains. We have identified CC strains that diverge in their anti-tumor immune responses and are characterizing the molecular mechanisms responsible for these differences. Ultimately, these diverse genetic traits may lead to the development of novel therapies for cancer.

Concerns are growing over urban drinking-water quality due to an inefficient management infrastructure in most low-income countries. Outbreaks of waterborne were linked to extreme climatic events, despite that the causal relationship between change on rainfall patterns, temperature rise and drinking water microbial quality is complex, involving an interplay of the type of water supply, water source and water treatment technology. Antananarivo, the capital of Madagascar is witnessing rapid urbanization, growing by additional 100,000 new inhabitants a year, that is increasing the already acute pressure on infrastructure and deficient local services. . Water supply date back to the colonial period (1952) and is outpaced by urban expansion and population growth. Consequently, home connections are still limited and a network of around 900 standpipes supply un-piped households. Weekly analyses of the water quality are conducted in our laboratory on behalf of the Commune urbaine d'Antananarivo. The aim of this project is to analyse the time serie of theses data in relation with rainfalls , to provide advise on the way to condut water purification in relation with climat condtions

A number of mammalian cell types are susceptible to Salmonella Typhimurium infection, including epithelial cells, fibroblasts and macrophages. It has recently been demonstrated that Salmonella display specific lifestyles in a host cell type-specific manner, where these lifestyles are remarkable for the subcellular localization and replication rate of Salmonella. During epithelial cells infection, Salmonella are first uptaken by the host cell and being encapsulated in a unique endocytic compartment termed Salmonella-containing vacuole (SCV). Within the SCV, Salmonella could remodel the SCV into a viable replicative niche or rupture the SCV and hyper-replicate in the host cytosol. Salmonella replicate at distinct rates in the two localizations, the Salmonella replication in SCV commences from 5 hours post-infection (pi) and infected host cell harbors less then 10 bacteria at 8h pi. While the cytosolic Salmonella begins replication within the first hour of infection at a rate of 30 minutes per division and accumulates up to over 50 bacteria in the host at 8h pi. To understand how Salmonella achieves the two distinct intracellular lifestyles as well as the pathophysiological impacts of the two lifestyles, the primitive goal of my project is to develop a bacterial-borne fluorescent reporter that clearly depicts the subcellular localization and replication rate of Salmonella. With this multiplex fluorescent reporter, we will set to explore the fundamental biological questions: to determine the immune response of epithelial cells against the two Salmonella lifestyles.

Enteroviruses are known to recombine a lot during the replication cycle. A lot of viruses produce defective genomes, which are generated by the polymerase skipping several nucleotides and thus, forming internal deletions of the genome. We would like to look at this process more closely and come up with a model, which includes the role of the RNA virus genome itself, including its structure.

Complex chronic diseases are caused by the accumulation of genetic, microbial and lifestyle factors. The number and complexity of such factors makes prediction of pathogenesis and therapy particularly difficult. Although a single factor is rarely sufficient to trigger pathology, genetic and environmental factors have so far been studied in isolation. Nevertheless, a substantial number of genetic variants have been associated with disease risk and the concomitant lifestyle shift and excessive hygiene are thought to contribute to the increased incidence in inflammatory diseases in industrialized countries. Moreover, clinical and experimental observations suggest a strong impact of gut microbiota on susceptibility to inflammatory diseases. The aim of 3D PATH is to explore the multiplicity and complexity of genetic, microbial and lifestyle factors associated with vulnerability to inflammatory pathology, using mice of the Collaborative Cross (CC), that model human genetic variability. Quantitative trait loci analyses, as well as integrative data analyses on metabolic and inflammatory outcomes will reveal new genetic variants and combinations of variants associated with disease susceptibility, and whether alterations of the gut microbiota in genetically susceptible mouse strains can trigger the phenotype. Moreover, the longitudinal design of experiments will allow us to identify early biomarkers that predict the pathology later in life. In a second step, validation of the identified risk factor combinations and exploration of the underlying molecular mechanisms will be performed taking advantage of the mouse model.

The quality of the samples stored in biolocial resources centers is a real concern at the international level. Recent scientific publications highlighted difficulties for reproducing published scientific results which constitute a brake to consequent developpment of medical applications.. The quality of the samples used in experiments may partly explain those difficulties. Within the ICAReB platform, samples dating from 1950 are conserved. The question of their quality and usability is posed. Our main objective is therefore to idnetify universal markers of quality for blood derived samples which constitutes the most frequent biological material stored in biobanks.

E. coli sequence type 131 is primarily responsible for 40-80% of extended-spectrum beta-lactamase (ESBL) infections causing million antimicrobial resistant infections annually. Population genetic analyses indicate that ST131 consists of three different sublineages, clade A, B and C, genetically defined by polymorphisms in the gene fimH (fimH41, H22 and H30, respectively). The Cytotoxic necrotizing factor 1 (CNF1) is one major Uropathogenic E. coli (UPEC) virulence factor that catalyzes a pro-oncogenic mutation on Rho GTPases and triggers pejorative inflammatory responses. E. coli ST131 were first reported to lack some UPEC key virulence factors among which CNF1 but recently we and other groups have noticed the presence of the cnf1 gene in some ST131 isolates but the occurrence of CNF1 among E. coli ST131 is still unknown and in order to better define the success of pandemic MDR E. coli the benefit of cnf1 carriage must be elucidated. To address this question, by using bio-informatics approaches the present study analyzed the distribution and the evolution of CNF1 in E. coli ST131 isolates and also examined the association between the presence of CNF1 and antibiotic resistance genes.

Lyme borreliosis (LB) is an important tick-borne disease which can cause a broad range of symptoms mainly affecting the skin, the nervous system and the joints. It is caused by bacteria of the Borrelia burgdorferi sensu lato (s.l.) complex. In Europe, at least five genospecies are known to be pathogenic, namely Borrelia afzelii, Borrelia garinii, B. burgdorferi sensu stricto, Borrelia spielmanii and Borrelia bavariensis. In order to assess the health burden, data on the incidence of all the different clinical manifestations are required. The National Reference Centre for Borrelia collected epdiemiological, clinical and biological data from general practioners and hospitals of patients bitten by Ixodes ticks from 2003 to 2011. This large amount of data needs statistical analyses both univariate and univariate in order to obtain a global and precise vision of all the elements allowing us to understand this disease, both in the complexity of its symptoms and its management but also in the context of its prevention.

We are interested in Spondyloarthritis. Spondyloarthritis is a chronic inflammatory rheumatism. Currently 2 biologic treatments are available : anti TNF and anti IL-17A. We are analyzing how these treatments modify the immune system of the patients. The goal of this part of the project is to describe how biologics treatments in Spondyloarthritis modifiy the frequence of immune cell populations.

Glioblastoma cells interconnect forming a functional and resistant network. We are investigating the role of these connections in the cancer relapse and treatment-resistance

soumis plus tard

We aim to establish a comparison of the genetic diversity of different Yersinia spp. genomes and their geographic coordinates in order to characterize the possible associations of genotypes and spatial distances from an epidemiological point of view

Hydrogen Deuterium eXchange followed by Mass Spectrometry (HDX-MS) is a recognized biophysical tool in structural biology capable of probing protein/ligand interactions, conformational changes, and protein folding and dynamics. Over the last decade, major improvements in the technology have been made (i.e., refrigerated UHPLC system, mass spectrometers with enhance resolution and sensitivity…) allowing the structural analysis of highly challenging biological systems. The characterization of such biological systems results in very complex HDX-MS datasets for which specific analytical software are needed. In this context, our group and the C3Bi have developed “MEMHDX” (Mixed-Effects Model for HDX experiments) to aid in the rapid statistical validation and the visualization of large HDX-MS datasets. This web application is freely accessible to the HDX-MS scientific community at the project home page http://memhdx.c3bi.pasteur.fr The current version of the application allows for the comparison of two unique conditions using only one unique charge state. This limitation has been pointed out by several MEMHDX users. The current project aims at designing and implementing new functionalities in MEMHDX to enhance its analytical capabilities. The possibilities for users to compare multiple HDX-MS conditions using multiple charge states will be introduced within the web application and the visualization tool provided by MEMHDX will be modified accordingly.

As part of a collaboration between the CETEA, the C2RA and the Hub of Bioinformatics and Biostatistics, we aim at refining the experimental projects by improving their design through reviewing projects, training project designers and developing softwares.

Background : The Immunoregulation Unit is composed at present of: Lab Head, one senior staff scientists, two “ingegnieurs” (one IP, one Fondation APHP), two PhD students. The focus of the research is the study of immuno-mechanisms in the pathogenesis of chronic inflammatory diseases, and of the molecular basis of response to treatment. All members of the lab have expressed an interest in acquiring basic R skills for the analysis of large gene expression data sets, collected from the study of patients’ samples. Only one PhD student in the lab is currently using R tools for data analysis, the other members have all received some previous instructions in biostatistics and/or R, but have not been using R tools currently. Requirements : Lab members have expressed a specific need to be instructed in the following areas: 1.refresh basic notions of R language, with a particular focus on handling large gene expression data sets 2.introduction to graphic tools for data representation (ggplot) 3.introduction to tools for differential gene expression analysis (limma) 4.data exploration using Principal Component Analysis Constraints : 1. For the course, it has been decided to use data generated by the lab. Placing the course in the lab’s data context has the advantage of ensuring that the course content is adapted to the “real-life” situations that lab members face in the analysis of their own data. 2.The present situation of “confinement” due to the Covid19 pandemic offers some opportunities (time availability of all members to follow the instruction), but obvious restriction. To maintain interactivity, classes are held at a distance, using Skype group meetings.

Chlamydia trachomatis is an intracellular bacterium. We have observed that some of the epigenetic changes in the host that occur in infection can be reversed by modifying the culture conditions. We will measure the impact this has on the global transcriptional response of the host to infection.

Ce projet, discuté avec le groupe « Statistiques », a pour but de proposer une analyse statistique des données quantitatives de phénotypage à haut débit générées au laboratoire. Le groupe Statistiques se propose de former et d’accompagner C. Maufrais à ce type d’analyse. Notre jeu de données de phénotypage consiste en des données multivariées (mesure de 16 variables sur 42 souches cultivées dans 100 conditions de croissance, avec réplicats biologiques et techniques).

The key role of CD8+ T-cells in controlling HIV replication has been particularly well established. Functional and metabolic properties of HIV specific CD8+ T cells appear to be essential for an effective control of the virus, as shown in HIV-1 and HIV-2 controllers. Mounting of functional CD8+ T cell responses is dependent on the effective priming of optimal antigen specific memory like CD8+ T-cells. However, factors that may dampen or promote effective priming of CD8+ T-cell responses during HIV infection remain largely unknown. Our aim is to investigate potential factors that may help us improving the induction or reprogramming of robust CD8+ T cells against HIV. We propose to study functional and metabolic attributes of HIV specific CD8+ T cells from HIV controllers and non controllers and determine if defects in CD8+ T cells form non controllers can be corrected with small molecules targeting the molecular program of the cells; de novo priming of HIV specific CD8+ T cells can be altered by antigen presenting cell-derived factors. The results of this project will have direct implications for our understanding of natural immune control of HIV, as well as the optimization of vaccine strategies or immune therapies against HIV.

With an estimated 1031 particles on earth, bacteriophages are the most abundant genomic entities across all habitats and important drivers of microbial communities. Growing evidence suggest that they play roles in intestinal human microbiota homeostasis, and recent metagenomics studies on the viral fraction of this ecosystem have provided crucial information about their diversity and specificity. However, the bacterial hosts of this viral fraction, a necessary information to characterize further the balance of these ecosystems, remain poorly characterized. Here we unveil, using an enhanced metagenomic Hi-C approach, a large network of 6,651 host-phage relationships in the healthy human gut allowing to study in situ phage-host ratio. We notably found that half of these contigs appear to be sleeping prophages whereas ¼ exhibit a higher coverage than their associated MAG representing potentially active phages impacting the ecosystem. We also detect different candidate members of the crAss-like phage family as well as their bacterial hosts showing that these elusive phages infect different genus of Bacteroidetes. This work opens the door to single sample analysis and concomitant study of phages and bacteria in complex communities.

HPV RNA-Seq, a novel and unique molecular test that allows detection of pre-cancerous lesions of the cervix from cervical samples.

We are working on the validation of protein interactions between SARS-CoV-2 proteins and human proteins that have been identified by Bio-ID. Our project is the validation of those interactions using our NanoLuciferase two-hybrid system.

Establishment of a left-right asymmetry is essential for the function of the heart, which is to ensure a double blood circulation. This asymmetry is initiated during an embryonic process, in which the heart tube acquires a loop shape. The molecular cascade at the origin of left-right asymmetry is well established and involved in the severe heart defects of the heterotaxy syndrome. However, another 20% of heart malformations display cardiac chamber misalignment and their origin is poorly understood. Using a mutant mouse model and expertise in heart morphogenesis, we want to provide novel insight into malformations displaying an abnormal alignment of ventricles.

Complex chronic diseases such as type 1 and 2 diabetes are caused by the accumulation of genetic, microbial and lifestyle factors. The number and complexity of such factors makes prediction of pathogenesis and therapy particularly difficult. Although a single factor is rarely sufficient to trigger pathology, genetic and environmental factors have so far been studied in isolation. Nevertheless, a substantial number of genetic variants have been associated with disease risk and the concomitant lifestyle shift and excessive hygiene are thought to contribute to the increased incidence in inflammatory diseases in industrialized countries. Moreover, clinical and experimental observations suggest a strong impact of gut microbiota on susceptibility to inflammatory diseases. The aim of 3DPATH is to explore the multiplicity and complexity of genetic, microbial and lifestyle factors associated with vulnerability to inflammatory pathology, with a particular focus on type 1 and 2 diabetes, using mice of the Collaborative Cross (CC), that model human genetic variability. Quantitative trait loci analyses, as well as integrative data analyses on metabolic and inflammatory outcomes will reveal new genetic variants and combinations of variants associated with disease susceptibility, and whether alterations of the gut microbiota in genetically susceptible mouse strains can trigger the phenotype. Moreover, the longitudinal design of experiments will allow us to identify early biomarkers that predict the pathology later in life. In a second step, validation of the identified risk factor combinations and exploration of the underlying molecular mechanisms will be performed taking advantage of the mouse model.

Autism Spectrum Disorder (ASD), a disorder of social communication and restricted and stereotyped interests, represents a major societal challenge with its prevalence of 2.93% (Baio et al., 2018). Since genetic factors have been identified, their links with phenotypic expression (incl. neuroanatomical aspects) are being explored (Bourgeron et al., 2015). The first neuroanatomical studies are promising, and reinforced by the development of interaction neurosciences, notably with the high-density electroencephalography (HD-EEG). Among different EEG markers, the alpha rhythm (AR), an indirect marker of neuronal synchronization (Hummel et al., 2002) is described differently in ASD; especially during social interaction tasks at the parietal level and the upper temporal sulcus, areas involved in the "mirror neuron system" (Rizzolatti & Craighero, 2004) – then, described as “broken” in ASD (Oberman et al., 2005). More specifically in a sub-band of the AR, at the frontal and parietal levels, AR anomalies suggest more visual attention implication (Dumas et al., 2014). Differences are also described over low and high EEG frequencies in ASD (Kozhushko et al., 2018). We hypothesize that, integrating spectral, spatial and dynamic (involving ASD symptoms) dimensions, would identify EEG markers, highlighting the underlying electrophysiological mechanism of ASD, but also providing an early and accurate diagnosis (Engeman et al., 2015, 2018), key to a favorable prognosis in ASD.

Nous étudions la toxine CNF1 des E. coli uropathogènes. Cette toxine active des protéines ayant des activités pro-oncogéniques et pro-inflammatoires. Ces E. coli peuvent être en portage asymptomatique dans la flore intestinale de patients sains. Par des mesures quantitative du taux d’anticorps anti-CNF1 sérique nous cherchons à définir l’exposition de ces patients à cette toxine. Ici nous cherchons à définir si les différences mesurées entre groupes de patients sont significatives.

La pandémie de la COVID-19 est un défi médical inédit en particulier du fait de la nature systémique de cette pathologie. En effet, la COVID-19 affecte à la fois plusieurs organes et systèmes. L’atteinte cérébrale s’effectue de plusieurs façons : infection directe des cellules nerveuses par le SRAS-CoV-2, inflammation du système nerveux central avec, entre autre, invasion de lymphocytes T et activation de la microglie, inflammation systémique sévère qui inonde le cerveau d'agents pro-inflammatoires et endommage ainsi les cellules nerveuses, ischémie cérébrale globale liée à une insuffisance respiratoire, accidents thromboemboliques liés à une augmentation de la coagulation intravasculaire et stress psychologique sévère. En conséquence, la COVID-19 se manifeste parfois par des symptômes neurologiques et neuropsychiatriques tels que des vertiges, des troubles du sommeil, des déficits cognitifs, un délire, ou une dépression sévère. La perte soudaine de l'odorat est un symptôme fréquemment associé à la COVID-19 et l'infection par le SARS-CoV-2 des neurones du système olfactif a été signalée à la fois chez le hamster et l'humain. La grande majorité des patients atteints de la COVID-19 retrouvent leur fonction olfactive en quelques semaines. Cependant une minorité significative de personnes infectées (1 sur 5 cas), souffre toujours de troubles olfactifs (anosmie, hyposmie et/ou parosmie) plusieurs mois après la primo-infection. Ces troubles olfactifs sont fréquemment associés à un comportement dépressif et à des plaintes cognitives. En TEP, il est même possible de corréler ce dysfonctionnement cognitif à un hypométabolisme de certaines régions cérébrales, y compris le gyrus olfactif. Ce projet propose d'évaluer et de suivre l’évolution, durant un an, des capacités olfactives de patients atteints de trouble persistant de l’odorat depuis un an (+/- 3 mois) des suites de la COVID-19. Il permettra de mieux distinguer si les troubles olfactifs de longue durée sont liés à une atteinte du système olfactif périphérique (en raison d’une persistance virale locale et/ou d’une inflammation chronique de l’épithélium olfactif nasal), ou du système nerveux central. En particulier, l’enregistrement des potentiels évoqués olfactifs permettra d'objectiver les capacités olfactives, de manière non déclarative. Cette étude pourra servir de base au développement d’études visant à évaluer les risques cliniques neurologiques et/ou psychiatriques associés à la forme chronique des troubles de l’odorat des suites de la COVID-19.

Nod2 is expressed on brain neurons, however the downstream effects of its activation by its ligand MDP are not know. We used RNAseq strategy to answer this question

La coqueluche est une infection respiratoire communautaire causée par la bactérie Bordetella pertussis (Bp). Elle est à l’origine d’un nombre important d’hospitalisations malgré une couverture vaccinale élevée, et est responsable d’une mortalité conséquente. La forme la plus sévère de cette maladie, la coqueluche maligne, est observée chez des nourrissons âgés de moins de 3 mois et est caractérisée par une détresse respiratoire aigüe, une défaillance multiviscérale avec une atteinte neurologique manifestée par des convulsions voire un coma, ainsi qu’une hyperleucocytose majeure, responsable d’un taux de mortalité particulièrement élevé. La physiopathologie de la coqueluche notamment celle de sa forme maligne demeure indéterminée. En effet, le type de cellules immunitaires et les gènes impliqués dans la réponse immunitaire à Bp restent encore inconnus. Nous émettons l’hypothèse que la forme maligne de la coqueluche est due à la combinaison de facteurs de virulence spécifiques et une réponse immunitaire « immature » du jeune nourrisson. Ainsi, l’objectif du travail est de déterminer l’implication de la réponse immunitaire systémique néonatale dans la sévérité de la coqueluche, à travers une approche transcriptomique.

A phenotypic study of antifungal tolerance have been performed with a collection of 100 mutant strains of C. glabrata and a statistical analysis of these data should be conducted.

Chronic inflammatory systemic diseases (CIDs) are a burden to humans because of life-long debilitating illness, increased mortality and high therapy costs. CIDs’ increasing prevalence in western countries has indeed placed them at the third rank of morbi-mortality causes. Unfortunately, available treatments are poorly targeted and non-curative. That is partly linked to a complex and largely ununderstood pathophysiology. Genetic susceptibility clearly plays a role. Genes linked to the immune system have been identified, but causal genes remain mostly unknown and other factors such as intestinal microbiota have also been implicated. The complexity of CIDs’ pathophysiology suggests that a holistic approach is the most susceptible to help make significant progress. Our project intends to take advantage of recent technical progress and development of informatics tools to set up a transversal approach. High-resolution sequencing technology indeed quickly produces large amounts of accurate data. Besides, new integrative informatics tools allowing storage and integrative analysis of this resulting high amount of data are now available. We intend to set-up a CID’s network allowing the gathering and extensive analysis of data related to immuno-genetic determinants, immune repertoire and microbiota from individuals suffering from one of the three major interlinked CIDs, namely Hidradenitis Suppurativa (HS), Crohn’s disease (CD) and Spondyloarthropathy (SpA) as compared to healthy volunteers.

It has been shown that methylation can act as a kind of memory of the immune system. For patients with co-infections, it is of particular importance to know when to begin an anti-retroviral therapy, especially if they are already infected with tuberculosis. The goal of this study is to find hyper or hypo methylated loci related to the reaction of HIV patients (co-infected or not) to different kind of treatments.

This project aims at identifying novel genetic traits that regulate the anti-tumor activities of NK cells and homeostasis of NK cells and other ILC using an unique mouse resource, the Collaborative Cross (CC). CC is a panel of recombinant inbred mice derived from randomized breeding of eight laboratory inbred strains combining high genetic diversity with the advantage of inbred mouse strains. We have identified CC strains that diverge in their anti-tumor immune responses and are characterizing the molecular mechanisms responsible for these differences. Ultimately, these diverse genetic traits may lead to the development of novel therapies for cancer.

Taking advantage of a murine model of controlled microbiota composed of 12 strains, we evaluated the activity of a cocktail of three virulent bacteriophages to target a murine Escherichia coli strain in the mammalian gut.

In this project we study ecological diversification of Klebsiella pneumoniae and closely related species. Using comparative genomics we want to identify the pattern of genome adaptation to different environments

Anti-TNF therapy has revolutionized treatment of many chronic inflammatory diseases, including rheumatoid arthritis, Crohn’s disease and spondyloarthritis (SpA). However, clinical efficacy of TNF-inhibitors (TNFi) is limited by a high rate of non-responsiveness (30-40%) both in SpA and other diseases, exposing a substantial fraction of patients to important side-effects without any clinical benefit. Despite the extensive use of TNFi since many years, it is still not possible to determine which patients will respond to TNFi before treatment initiation. In this study, we have tested the hypothesis that the functional analysis of immune responses may not only improve our understanding of the molecular mechanisms of TNF-blocker activity, but also identify correlates of therapeutic responses in SpA patients. To facilitate the potential translation of our findings into a clinical setting, we have used standardized whole-blood stimulation assays (“TruCulture” assays, Duffy et al., Immunity 2014), and have minimized sources of pre-analytical variability, implementing a highly sensitive and robust pipeline to assess immune functions in patients. To investigate the concept that the immune status of a patient will define their response to TNFi treatment, we have used machine-learning algorithms to identify, in whole-blood stimulation assays, immunological transcripts that correlate with clinical efficacy of TNFi. Our results obtained with a cohort of 67 SpA patients demonstrate that high expression, before treatment initiation, of molecules associated with leukocyte invasion/migration and inflammatory processes predisposes to favorable outcome of anti-TNF therapy, while high-level expression of cytotoxic molecules was associated with poor therapeutic responses to TNF-blockers. These findings may suggest that SpA patients whose immune response is characterized by strong, NF-kB-mediated inflammation are more likely to benefit from TNFi treatment than patients with an active T/NK-cell component. Unfortunately our manuscript describing these results has been rejected by Nature Medicine. However, in her letter the editor mentioned, “Should future experimental data allow you to demonstrate that the identified gene signatures predict response to treatment and outperform previously reported approaches in an independent cohort, we would be happy to look at a new submission…”. We have recruited additional SpA patients over the summer and we are currently in the process of performing the gene expression analysis. The goal of this bioinformatic analysis will be to identify transcripts in stimulated immune cells that predict therapeutic outcome in a training set of patients using machine-learning algorithms and validate the findings in a replication cohort.

Mitochondria are double-membrane bound organelles that are essential in every tissue of the body. They are metabolic hubs and signalling platforms that are deeply integrated into cellular homeostasis. The functions of mitochondria are intimately linked to their form, which is regulated by a balance of membrane fusion and fission: dynamin-like GTPases OPA1 and MFN1/2 perform membrane fusion and DRP1 regulates membrane fission. Mutations in mitochondrial genes cause a pleiotropic spectrum of clinical disorders whose underlying genetic, morphological and biochemical defects can be easily studied in skin fibroblasts generated from patient biopsies. The morphology of mitochondria is inextricably linked to its many essential functions in the cell and we are interested in understanding the relationship between mitochondrial shape changes and metabolism in the context of acquired and inborn human diseases. Balanced fusion and fission events shape mitochondria to meet metabolic demands and to ensure removal of damaged organelles. Mitochondrial fragmentation occurs in response to nutrient excess and cellular dysfunction and has been observed in mitochondrial genetic diseases and is thought to play an important role in the development of disease. The physiological relevance of mitochondrial morphology and the mechanisms that regulate mitochondrial dynamics are incomplete and so we have set out to find ways to rebalance mitochondrial dynamics in genetic diseases. We recently developed imaging and informatics pipelines to allow for the automated, rapid, reliable quantification of mitochondrial morphology in human fibroblasts. We applied this new technology in the context of genome-wide siRNA screens in immortalized fibroblasts from an OPA1 patient with dominant optic atrophy and control fibroblasts to identify candidate genes able to reverse the mitochondrial fragmentation phenotype associated with mitochondrial dysfunction in patient cells. We have performed the same genome-wide screen in healthy immortalized control fibroblasts. Together, these studies will help us identify lists of genetic modifiers and therapeutic targets that can be investigated further using cell biology and biochemical tools in the lab.

Our goal is to have a bioinformatic tool that performs the 2 x 2 comparison of matrices of numbers in matrix batches. Each matrix corresponds to the use of gene fragments (V or J) to create a re-arranged gene (VJ) encoding a specific antibody, identified by droplet microfluidic or flow cytometry techniques followed by high throughput sequencing (NGS). ). The matrices are made for the two chains encoding the specificity of an antibody: the heavy chain (VH) or the light chain (VL). The goal is to compare VH matrices one against another, and VL matrices one against another for antibody gene rearrangements in mice, llama, and humans.

This project is integrated in the analysis of the gut ecosystem of children implicated in the AFRIBIOTA project, a translational project performed within a consortium of researchers and medical doctors from the Central African Republic, Madagascar, France and Canada (see https://research.pasteur.fr/fr/program_project/the-afribiota-project/). AFRIBIOTA aims at understanding the risk factors and pathophysiological changes underlying chronic child malnutrition as manifested through delayed growth. Within the project submitted, we aim at assessing a possible link between asymptomatic pathogen carriage, gut inflammation and stunted growth of children included in the study site in Antananarivo, Madagascar.

Several bacterial pathogens compromise the barrier function of endothelia by triggering the opening of transendothelial cell macroaperture (TEM) tunnels as large as several micrometres in width. This phenomenon has been linked to the dissemination of Staphylococcus aureus via the haematogenous route. The opening of TEMs occurs in response to the overall relaxation of the actomyosin cytoskeleton and cell spreading-associated with a disruption of focal adhesions via either toxin-induced inhibition of RhoA signaling or increase of the flux of cyclic-AMP broad signaling molecule. The principles of dewetting, i.e. the spontaneous withdrawal of a liquid film from a non-wettable surface by nucleation and growth of dry patches, explain the physical phenomena underpinning the opening of TEM tunnels. For both liquid and cellular dewetting, the growth of holes is governed by a competition between surface forces and line tension that limit the TEM widening. By conducting high-resolution microscopy approaches we unveil the presence of an actomyosin cable encircling TEMs. We have developed a theoretical cellular dewetting framework to interpret TEM physical parameters that are quantitatively determined by laser ablation experiments. We establish the critical role of ezrin and non-muscle myosin II (NMII) in building actin cables along TEM edges to progressively implement line tension that limits TEMs enlargement.

Globally one out of four children under 5 years is affected by linear growth delay (stunting). This syndrome has severe long-term sequelae including increased risk of illness and mortality and delayed psychomotor development. Stunting is a syndrome that is linked to poor nutrition and repeated infections. To date, the treatment of stunted children is challenging as the underlying etiology and pathophysiological mechanisms remain elusive. We hypothesize that pediatric environmental enteropathy (PEE), a chronic inflammation of the small intestine, plays a major role in the pathophysiology of stunting, failure of nutritional interventions and diminished response to oral vaccines, potentially via changes in the composition of the pro- and eukaryotic intestinal communities. The main objective of AFRIBIOTA is to describe the intestinal dysbiosis observed in the context of stunting and to link it to PEE. Secondary objectives include the identification of the broader socio-economic environment and biological and environmental risk factors for stunting and PEE as well as the testing of a set of easy-to-use candidate biomarkers for PEE. We also assess host outcomes including mucosal and systemic immunity and psychomotor development. AFRIBIOTA is a case-control study for stunting recruiting children in Bangui, Central African Republic and in Antananarivo, Madagascar. In each country, 460 children aged 2–5 years with no overt signs of gastrointestinal disease are recruited (260 with no growth delay, 100 moderately stunted and 100 severely stunted). We compare the intestinal microbiota composition (gastric and small intestinal aspirates; feces), the mucosal and systemic immune status and the psychomotor development of children with stunting and/or PEE compared to non-stunted controls. We also perform anthropological and epidemiological investigations of the children’s broader living conditions and assess risk factors using a standardized questionnaire. To date, the pathophysiology and risk factors of stunting and PEE have been insufficiently investigated. AFRIBIOTA will add new insights into the pathophysiology underlying stunting and PEE and in doing so will enable implementation of new biomarkers and design of evidence-based treatment strategies for these two syndromes. These analyses comprise the child development aspects of AFRIBIOTA.

We need an independent statistician to confirm that appropriate statistical tests were used to analyze the data in your manuscript for the final revision of our manuscript in Science Signaling (Manuscript Number: aar3993, \"LGP2 binds PACT to regulate RIG-I- and MDA5-mediated antiviral response\" ). Sincerely yours, Anastassia Komarova

Without new treatment development tuberculosis could cause about 70 million deaths by 2050, mostly due to the spread of multidrug-resistant strains. The standard drug regimen still builds on the first drugs introduced decades ago, and takes 6 months in the case of drug-sensitive tuberculosis, and up to 2 years in the case of drug-resistant tuberculosis, with heavy side effects. This long therapeutic regimen often results in patients not being able to follow it or complete it correctly, which promotes the chronicity of the infection and ultimately the onset of drug resistance. Although a few new molecules have been discovered, improving both the quality and the duration of tuberculosis chemotherapy remain pressing needs. Furthermore, the failure of chemotherapy is not only due to genetic resistance, which takes relatively long to occur, but also to the intrinsic ability of mycobacteria to diversify in discrete phenotypic states, which can endure drugs even in the absence of genetic mutations. This phenomenon, known as persistence, can eventually favor the onset of resistance, with major repercussions on disease control. In sum, tuberculosis therapy presents many challenges and in our view it is critical to study the ability of a drug or a drug combination to sterilize discrete subpopulations, which may either pre-exist in the population or result from adaptive processes. We found that, prior to drug exposure, phenotypically distinct subpopulations exist that display different drug susceptibility. In light of this, we hypothesized that phenotypic variation from cell to cell favors persistence and can consequently bring about treatment failure. Here we aim to identify molecules that reduce phenotypic variation, making the population more uniformly and rapidly susceptible to standard treatment. To this end, we developed a microfluidic system that allows us to track single cells by live imaging and to carry out a screening at the single-cell level, looking for molecules that homogenize the bacterial population and enhance the effectiveness of the standard treatment. Our approach could ultimately offer original therapeutic strategies towards better control of tuberculosis.

Complex chronic diseases are caused by the accumulation of genetic, microbial and lifestyle factors. The number and complexity of such factors makes prediction of pathogenesis and therapy particularly difficult. Although a single factor is rarely sufficient to trigger pathology, genetic and environmental factors have so far been studied in isolation. Nevertheless, a substantial number of genetic variants have been associated with disease risk and the concomitant lifestyle shift and excessive hygiene are thought to contribute to the increased incidence in inflammatory diseases in industrialized countries. Moreover, clinical and experimental observations suggest a strong impact of gut microbiota on susceptibility to inflammatory diseases. The aim of 3D PATH is to explore the multiplicity and complexity of genetic, microbial and lifestyle factors associated with vulnerability to inflammatory pathology, using mice of the Collaborative Cross (CC), that model human genetic variability. Quantitative trait loci analyses, as well as integrative data analyses on metabolic and inflammatory outcomes will reveal new genetic variants and combinations of variants associated with disease susceptibility, and whether alterations of the gut microbiota in genetically susceptible mouse strains can trigger the phenotype. Moreover, the longitudinal design of experiments will allow us to identify early biomarkers that predict the pathology later in life. In a second step, validation of the identified risk factor combinations and exploration of the underlying molecular mechanisms will be performed taking advantage of the mouse model.

The provision of human biological material collected, processed and stored under optimal conditions is crucial to ensure the quality of research carried out downstream. These optimal conditions must be determined by a rational method validation approach taking into account the critical parameters of the different biological sample management processes that are likely to have an impact on their quality.

The therapeutic anti-IgE antibody Omalizumab is used for the treatment of severe asthma, and is known to trigger anaphylaxis in some patients. Since Omalizumab is a humanized IgG1, so we hypothesized that Omalizumab could trigger anaphylaxis through the alternative FcgR-mediated pathway. Indeed, we observed that Omalizumab can trigger anaphylaxis in genetically modified mice expressing human FcgRs. We further produced a mutant version of Omalizumab which can still block IgE but cannot bind FcgRs, and demonstrated that this mutant anti-IgE does not induce FcgR-mediated anaphylaxis.

Hi-C contact maps reflect the relative contact frequencies between pairs of genomic loci, quantified through deep-sequencing. Differential analyses of these maps facilitate downstream biological interpretations. However, the multi-fractal nature of the DNA polymer inside the cellular envelope results in frequency values spanning several orders of magnitude: contacts involving loci pairs at large genomic distance are much sparser compared to closer pairs. The same is true for poorly covered regions such as telomeres and repeated sequences. Poor coverage translates into low signal-to-noise ratios. There is no clear consensus to address this limitation. We present a fast, flexible procedure operating on simple data that takes into account the contacts in each region of a contact map. Binning is performed only when necessary on noisy regions, preserving informative ones. This results in high-quality, low-noise contact maps that can be conveniently visualized for rigorous comparative analyses.

Deconvolution of the polyclonal antibody response targeting HIV-1 allowed the identification of broadly neutralizing monoclonal antibodies (bNAbs) targeting the viral envelope. Infusion of bNAbs protects against HIV-1 acquisition and decreases viral load. bNAbs kill HIV-1-infected cells, modulate host immune responses, and, when associated to latency-reversal agents, delay viral rebound in animal models. These antiviral activities are mediated by the Fc region, which is required for optimal in vivo efficacy. Thus, the landscape of Fc effector functions triggered by bNAbs is under intense investigation. Our aim is to decipher the molecular mechanisms underlying the sensitivity of HIV-1-infected cells to Fc effector functions.

Epidemiological data report an association between obesity and inflammatory bowel disease (IBD). Furthermore, animal models demonstrate that maternal high fat diet (HFD) and maternal obesity increase susceptibility to IBD in offsprings. However, the mechanisms that translate maternal obesity and HFD into increased susceptibility to IBD later in life remain unknown. Here we report that excess calorie intake by neonatal mice, as a consequence of maternal HFD, forced feeding of neonates or low litter competition, leads to multiple causally-linked perturbations in the intestine that imprint the individual with long term susceptibility to IBD.

Adaptive immune cells play important role in pathogenesis of multiple sclerosis by infiltrating the central nervous system, thereby contributing to demyelination and maintenance of an inflammatory microenvironment. In particular, autoreactive T cells, CD4+ T helper and CD8+ T cells exert a detrimental effect, while CD4+ regulatory T cells (Treg) have impaired suppressive function. Interferon b (IFNb), a commonly prescribed treatment for relapsing-remitting multiple sclerosis (RR-MS) decreases relapse rates and brain disability progression. However, around 30% of patients are or become non-responsive to treatment. Our aim is to determine the immune signatures associated with clinical efficacy of IFNb treatment in RRMS patients

The aim of this project is to understand how inherited APC gene mutations affect the immune system of familial adenomatous polyposis patients, and to evaluate the potential contribution of altered immune responses to polyposis and intestinal cancer development in these patients. (see https://research.pasteur.fr/en/project/projet-de-recherche-clinique-impact-des-mutations-du-gene-apc-adenomatous-polyposis-coli-dans-les-reponses-immunes-anti-tumorales/)

Comparison of Microsatellites and Multi Locus Sequences Typing approaches. Fungi: Pneumocytis jirovecii

The transcriptome signature during rabies infection will be analyzed both in animal model (mouse) and in human, at the central nervous system level, to identify the main canonical pathways involved during the infection.

Oral administration is a preferred model for studying infection by bacterial enteropathogens such as Yersinia. In the mouse model, the most frequent method for oral infection consists of oral gavage with a feeding needle directly introduced in the animal stomach via the esophagus. In this study, we compared needle gavage to bread feeding as an alternative mode of bacterial administration.

Parvimonas micra is a gram+ anaerobic coccus bacteria associated with colorectal cancer (CRC). The stool of patients with CRC has higher Parvimonas micra concentration compared to healthy individuals. It is also present in the colonic mucosa of CRC patients. Even if we find it in the adjacent healthy tissue, it is predominantly found in the tumor. Furthermore, it is correlated with the CpG island methylator phenotype (CIMP), a particular subtype of CRC. More specifically, it is associated with the hyper-methylation of tumor suppressor gene promoters. To find out whether this bacteria is involved in the initiation of CRC, we have developed a model of a differentiated epithelial monolayer of human colonic primary cells. After co-culture with this microorganism, we found a significant increase in the global DNA methylation level of the cell genome compared to the bacteria-free control. Now we would like to determine whether this increase in DNA methylation is specific to certain regions of the genome. Therefore, we will use Illumina's Infinium MethylationEPIC BeadChip Kit.

We studied the impact of deletion of different component of a regulatory system on the transcription of specific genes.

The aim of this study is based on the analysis of the transcriptome during the infection with European bat lyssavirus type 1 (EBLV-1) in torpid bat. This study will be conducted using an in vitro model using another bat cell line from an European bat.

Hepatitis C virus (HCV) infection is a slow and asymptomatic progressive liver disease leading to metabolic disorders such as steatosis, an accumulation of lipid droplets (LDs) in hepatocytes. We have assessed the interplay between HCV variants recovered from chronically infected patients and LD content in infected hepatoma cells, through quantitative imaging approaches.

Modulation of infectious diseases transmission by climate conditions must be investigate in Sahel to prevent epidemics. Registration of data on flu transmission and on rainfalls+ temperature was conducted over the last ten years by the Flu national reference center in Niamey. Time series analysis must be conducted to investigate the correlation between the number of cases and climatic conditions.

Immune thrombocytopenia (ITP) is an autoimmune condition characterized by an autoantibody response against platelets, driven by pathogenic plasma cells often found in the spleen. This autoreactive plasma cell population remains poorly characterized, especially in terms of antibody affinity and anatomical distribution. In order to tackle this problem, we have developed a microfluidic platform to characterize platelet-specific plasma cells isolated from ITP patients, in terms of their IgG secretion rate and affinity for a platelet autoantigen at the single-cell level.

The LabEx Milieu interieur (MI) project is a clinical study aiming to define the natural variability of the human immune response. Fibroblasts were prepared from skin biopsies of 300 of the 1000 healthy donors (30 men and 30 women in each of 5 decades from 20 to 69 years) by Genethon. Each primary line is annotated by metadata derived from the systematic genotypic-phenotypic analysis Labex-MI (serology, genomic analyzes, proteomics, transcriptome, microbiota, clinical data and epidemiological selection criteria). The objective is to characterize the innate immune response of fibroblasts from healthy donors. We have developed approaches to obtain standardized measures of the immune response and to identify interindividual variance (Chansard et al., 2021) on a subset of sixteen primary fibroblast lines.. We observed that cell responses to LPS stimulation were distributed between “low” and “high” responders, while inter-donor variability of the response to poly I: C was very low. Poly I: C and LPS activate pathways from TLR3 and TLR4 receptors, respectively. We set up a real-time quantitative PCR assay of the 16 cells in parallel using the BioMark automated PCR system (Fluidigm) for comparative quantification of mRNAs baseline expression in the donors’ fibroblasts to check if low responses to LPS were due to a different expression of TLR4 and other factors of the pathway. We will extend the analysis to stimulated cells by Poly I: C ,LPS and other agonists of the innate immune response and also in parallel to cells infected by Leptospira interrogans.

We seek to make the appropriate statistical comparisons of oxygen consumption and mitochondrial membrane potential measurements in paired, high-resolution respirometry measurements between control and experimental samples

Factors determining RABV tropism are largely unknown. Here, we are identifying the susceptibilities and influence of glial cells on RABV infection.

Using reverse genetics, we produced recombinant viruses within a prototypic HCV strain backbone, by substituting its core coding sequence by the equivalent sequences from from clinical isolates of different HCV genotypes. To verify that heterologous core sequences did not impair cross-talk with prototypic viral elements and could be used for comparative studies, we monitored the viral replication of our set of core intergenotypic viruses. For this, we quantified the amount of intracellular viral RNA, secreted genomes and infectious titers at different time points following infection of hepatoma cells with the recombinant viruses.

New mouse genetic reference populations obtained from 8 distinct founder strains, including 3 wild-derived strains, have been developped since the 2000s and are now available. These populations captured around 95% of the existing murine genetic diversity and constitute a better model than standard inbred laboratory mouse strains. These populations constitute tools to identify new phenotypes and to map the causative genetic variants (QTL mapping) behind these phenotypes. These populations include : i) Collaborative Cross (CC) inbred strains; ii) Recombinant inbred between CCs (CC-RIXs) and iii) Diversity Outbred. These populations are specifically used in the Mouse Genetics Laboratory to identify new variants involved in host susceptiblity differences to pathogens.

This project addresses two main questions: does Chlamydia trachomatis modify glycolysis and/or oxidative phosphorylation in the host, and do the bacteria need these metabolic pathways to complete their developmental cycle.

Bacterial toxins can induce a wide range of life threatening diseases and are at risk of bioweapon development due to their extreme toxicity and ease of production. Some AB-like toxins exploit the host cell endocytic machinery to enter into the cell cytosol where they exert their poisoning effects. Host-targeted therapy involving the development of small molecules interfering with key vesicular trafficking components hijacked by bacterial toxins offers to counteract toxin action. We have identified the small compound C910, in a cell-based High-throughput screen (HTS) followed by orthogonal screens described in (Mahtal N et al., 2018), for its cell-protective activity against CNF1 toxin from pathogenic Escherichia coli, as well as diphtheria and Shiga toxins. Therefore, to characterize C910 mechanism of action and find its cellular target we have realized an siRNA wide-genome screening on primary human cells. This screening aims to find genes that can interfere with the trafficking of the CNF1 toxin.

In recent years, immune dysfunctions, including auto-immune mechanisms and peripheral inflammation, have been clearly associated with severe neuropsychiatric disorders like bipolar disorders (BD) and schizophrenia (SZ). These findings are supported by an extensive litterature highlighting a higher risk to develop neuropsychiatric disorders in patients suffering from auto-immune diseases and also the presence of low-grade inflammation and abnormal immunoglobulin rates in patients with psychosis. It is now well-established, since the description of paraneoplastic and auto-immune encephalitis, that antibodies targeting self-antigens such as membrane receptors or intracellular proteins could trigger psychiatric symptoms and severe inflammation. Therefore, an in-depth characterisation of circulating auto-antibodies and their clinical and/or biological implications has become a critical issue to stratify specific subgroups of patients with auto-immune psychosis in order to adjust and adapt the treatment and care, and develop novel approaches. Nicotinic acetylcholine receptors (nAChRs) have been linked to severe neuropsychiatric disorders by clinical and genome-wide association studies (GWAS). In addition to their key roles in neuronal function, nAChRs are also involved in the complex regulation of immuno-inflammatory processes both in the brain and the periphery, making them prime candidates to study the link between inflammation and major psychiatric disorders. Furthermore, nAChRs have already been identified as the target of autoimmune mechanisms leading to the destruction of the neuromuscular junction in the well-described autoimmune disease, myasthenia gravis. Based on these findings, we have started to dissect auto-immune mechanisms against nAChRs involved in SZ and BD. In brief, anti-nAChR auto-antibodies contribute to cognitive dysfunction and psychotic symptoms through peripheral inflammation. Here, our goals are (1) to extend the current knowledge by dissecting the relationship between clinical features and peripheral inflammation (cytokines, chemokines, ...) (2) to stratify patients with anti-nAChR auto-immune psychosis by using cluster analyse

Vaccines against COVID-19 have been developed for use as homologous two-dose regimens and several of them have demonstrated efficacy. There is limited data on the clinical and the immune response induced by heterologous vaccination regimens (HVR) using alternate vaccine modalities. CORSER-4 is a Viro-Immunology cohort promoted by the Institut Pasteur that will follow-up subjects from the time they receive a prime vaccine dose or a boosting dose. We determined subjects sub-groups of interest defined by the type of vaccine immunization they receive: (i) Heterologous two-dose vaccine regimen, the less frequently used at the moment, (ii) Homologous two-dose vaccine regimen, the more frequently used; (iii) One-dose vaccine regimen and (iv) Infectious-prime vaccine-boost immunization in COVID-19-experienced patients. The subject will be enrolled on the planed last boost injection visit and 5 Follow-up visits will be further conducted (Month1, M3, M6, M12 and M24). We will collect longitudinal clinical data and biological samples. We will explore Viral and Immune Response in sera, nasopharyngeal secretions and in saliva samples. We will assess the immune response obtained by various vaccination regimen against the reference strains and the variants of concern, and the durability of the humoral and cellular response. In addition, we will document any occurring acute infection episode with a supplemental unscheduled visit in order to detect an emerging variant viral strain. Altogether, the CORSER-4 project constitutes an opportunity to evaluate early anti-SARS-CoV-2 immunity in heterologous (and others) vaccine regimens and to estimate their efficacy and their sustainable (M24) protection against circulating virus strains (reference and variants).

Mitochondria are dynamic organelles that undergo constant morphological changes, resulting from fusion and fission events. Mitochondrial fission is crucial for mitochondrial function, apoptosis, mitophagy, and mitochondrial segregation during mitosis. While core mitochondrial fission factors have been elucidated and characterized, it is unclear if additional molecules participate or are main players of the fission process. To solve this question, we setup a genome wide, high content imaging (HCI) screening to identify suppressors of mitochondrial fragmentation in Opa1-/- cells. The principle is that using cells deficient for mitochondrial fusion (ablated for the core fusion protein Opa1), we may identify fission factors by screening for genes for which the loss of function is able to complement Opa1-/- phenotype. This was validated in preliminary experiments of silencing of the core fission protein Drp1, where confocal and electron microscopy confirmed that ablation of Drp1 resulted in mitochondrial elongation in Opa1-/- cells without causing mitochondrial fusion in a classic polyethylene glycol fusion assay. Following miniaturization of the assay, we set up an efficient pipeline to perform an automated HCI screening in Opa1-/- MEFs transfected with a pooled siRNAs library targeting >19,000 genes. Automated imaging and high content image quantification allowed us to generate a list of potential hits, that we aim to process in collaboration with the lab of Timothy Wai and the C3BI HUB, in order to identify promising genes that will be validated and investigated in the future.

We observed that Chlamydia trachomatis infection results in deep changes in the histone methylation profile of the infected cells.