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Dagousset G.,University of Versailles | Simon C.,University of Versailles | Anselmi E.,University of Versailles | Anselmi E.,CNRS Infectiology and Public Health | And 3 more authors.
Chemistry - A European Journal | Year: 2017

We report the first use of N-trifluoromethylthiosaccharin as the source of SCF3 radical under photoredox catalysis. This allowed an efficient and general visible-light-mediated carbotrifluoromethylthiolation of alkenes. Under the optimized conditions using fac-[Ir(ppy)3] as the photocatalyst, various N-aryl acrylamides as well as a wide range of substituted styrenes can readily be difunctionalized in an intra- or intermolecular fashion, affording the corresponding SCF3-containing products in good to excellent yield. Importantly, the formation of this SCF3 radical along with other key radical intermediates was unambiguously demonstrated thanks to spin trapping/electron paramagnetic resonance (ST/EPR) experiments, which enabled a clear understanding of the reaction mechanism. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim


PubMed | CNRS Infectiology and Public Health, Collège de France, University of Poitiers, University of Tours and 2 more.
Type: Journal Article | Journal: PloS one | Year: 2016

The main features of lung infection and inflammation are a massive recruitment of neutrophils and the subsequent release of neutrophil serine proteases (NSPs). Anti-infectious and/or anti-inflammatory treatments must be tested on a suitable animal model. Mice models do not replicate several aspects of human lung disease. This is particularly true for cystic fibrosis (CF), which has led the scientific community to a search for new animal models. We have shown that mice are not appropriate for characterizing drugs targeting neutrophil-dependent inflammation and that pig neutrophils and their NSPs are similar to their human homologues. We induced acute neutrophilic inflammatory responses in pig lungs using Pseudomonas aeruginosa, an opportunistic respiratory pathogen. Blood samples, nasal swabs and bronchoalveolar lavage fluids (BALFs) were collected at 0, 3, 6 and 24 h post-insfection (p.i.) and biochemical parameters, serum and BAL cytokines, bacterial cultures and neutrophil activity were evaluated. The release of proinflammatory mediators, biochemical and hematological blood parameters, cell recruitment and bronchial reactivity, peaked at 6h p.i.. We also used synthetic substrates specific for human neutrophil proteases to show that the activity of pig NSPs in BALFs increased. These proteases were also detected at the surface of lung neutrophils using anti-human NSP antibodies. Pseudomonas aeruginosa-induced lung infection in pigs results in a neutrophilic response similar to that described for cystic fibrosis and ventilator-associated pneumonia in humans. Altogether, this indicates that the pig is an appropriate model for testing anti-infectious and/or anti-inflammatory drugs to combat adverse proteolytic effects of neutrophil in human lung diseases.


PubMed | National Polytechnic Institute of Toulouse, CNRS Infectiology and Public Health, French National Institute for Agricultural Research and French Atomic Energy Commission
Type: Journal Article | Journal: Physiological reports | Year: 2015

Pattern recognition receptors (PRRs) play a critical role in the detection of microorganisms and the induction of inflammatory and immune responses. Using PCR and Western-blot analysis, this study investigated the differential expression in the intestine of 14 PRRs and nine associated cytokines. Thirty-two pigs were used to determine the expression of these markers (1) along the proximal/distal axis of the small intestine (duodenum, jejunum, and ileum) and (2) between the intestinal segments and their respective lymphoid organs (Peyers patches [PP] and mesenteric lymph nodes [MLN]). Six additional animals were used to quantify the expression of these genes along the crypt/villus axis of jejunum, using microdissected samples. Most genes showed increased expression (1) in the distal than in the proximal parts of the small intestine (TLR3, 5, RIG-I, IL-1, IL-8, and IFN-); (2) in lymphoid organs (TLR1, 2, 6, 9, 10, IL-10, TNF-), especially the MLN (TLR4, 7, 8, NOD1, NOD2, NALP3, IFN-, IL-6, IL-12, and TGF-), than in intestinal segments. The analysis along the crypt/villus identified: (1) genes with higher expression in lamina propria (TLR1, 2, 4, 9, NOD1, NOD2, IL-1, IL-10, TGF-, TNF-) and (2) genes with higher expression in the villus (TLR3, 5, 6, RIG-I, IL-6). These results highlight the differential expression of PRRs and cytokines along the proximal/distal and the crypt/villus axis of the intestine, contributing to a fine analysis of the complex functional architecture of the small intestine and should be related to the gut microbiota.


Marques P.E.,Federal University of Minas Gerais | Oliveira A.G.,Federal University of Minas Gerais | Pereira R.V.,Federal University of Minas Gerais | David B.A.,Federal University of Minas Gerais | And 18 more authors.
Hepatology | Year: 2015

Drug-induced liver injury (DILI) is an important cause of acute liver failure, with limited therapeutic options. During DILI, oncotic necrosis with concomitant release and recognition of intracellular content amplifies liver inflammation and injury. Among these molecules, self-DNA has been widely shown to trigger inflammatory and autoimmune diseases; however, whether DNA released from damaged hepatocytes accumulates into necrotic liver and the impact of its recognition by the immune system remains elusive. Here we show that treatment with two different hepatotoxic compounds (acetaminophen and thioacetamide) caused DNA release into the hepatocyte cytoplasm, which occurred in parallel with cell death in vitro. Administration of these compounds in vivo caused massive DNA deposition within liver necrotic areas, together with an intravascular DNA coating. Using confocal intravital microscopy, we revealed that liver injury due to acetaminophen overdose led to a directional migration of neutrophils to DNA-rich areas, where they exhibit an active patrolling behavior. DNA removal by intravenous DNASE1 injection or ablation of Toll-like receptor 9 (TLR9)-mediated sensing significantly reduced systemic inflammation, liver neutrophil recruitment, and hepatotoxicity. Analysis of liver leukocytes by flow cytometry revealed that emigrated neutrophils up-regulated TLR9 expression during acetaminophen-mediated necrosis, and these cells sensed and reacted to extracellular DNA by activating the TLR9/NF-κB pathway. Likewise, adoptive transfer of wild-type neutrophils to TLR9-/- mice reversed the hepatoprotective phenotype otherwise observed in TLR9 absence. Conclusion: Hepatic DNA accumulation is a novel feature of DILI pathogenesis. Blockage of DNA recognition by the innate immune system may constitute a promising therapeutic venue. © 2014 by the American Association for the Study of Liver Diseases.


PubMed | Ludwig Maximilians University of Munich, CNRS Infectiology and Public Health, University of Oxford and Veterinary Research Institute
Type: Journal Article | Journal: PloS one | Year: 2016

In this study we determined protein and gene expression in the caeca of newly hatched chickens inoculated with cecal contents sourced from hens of different ages. Over 250 proteins exhibited modified expression levels in response to microbiota inoculation. The most significant inductions were observed for ISG12-2, OASL, ES1, LYG2, DMBT1-L, CDD, ANGPTL6, B2M, CUZD1, IgM and Ig lambda chain. Of these, ISG12-2, ES1 and both immunoglobulins were expressed at lower levels in germ-free chickens compared to conventional chickens. In contrast, CELA2A, BRT-2, ALDH1A1, ADH1C, AKR1B1L, HEXB, ALDH2, ALDOB, CALB1 and TTR were expressed at lower levels following inoculation of microbiota. When chicks were given microbiota preparations from different age donors, the recipients mounted differential responses to the inoculation which also differed from the response profile in naturally colonised birds. For example, B2M, CUZD1 and CELA2A responded differently to the inoculation with microbiota of 4- or 40-week-old hens. The increased or decreased gene expression could be recorded 6 weeks after the inoculation of newly hatched chickens. To characterise the proteins that may directly interact with the microbiota we characterised chicken proteins that co-purified with the microbiota and identified a range of host proteins including CDD, ANGPTL6, DMBT1-L, MEP1A and Ig lambda. We propose that induction of ISG12-2 results in reduced apoptosis of host cells exposed to the colonizing commensal microbiota and that CDD, ANGPTL6, DMBT1-L, MEP1A and Ig lambda reduce contact of luminal microbiota with the gut epithelium thereby reducing the inflammatory response.


PubMed | Wellcome Trust Sanger Institute, Moredun Research Institute, Tecnalia, University of Cambridge and CNRS Infectiology and Public Health
Type: | Journal: BMC genomics | Year: 2016

Mycobacterium avium subspecies paratuberculosis (Map) is an infectious enteric pathogen that causes Johnes disease in livestock. Determining genetic diversity is prerequisite to understanding the epidemiology and biology of Map. We performed the first whole genome sequencing (WGS) of 141 global Map isolates that encompass the main molecular strain types currently reported. We investigated the phylogeny of the Map strains, the diversity of the genome and the limitations of commonly used genotyping methods.Single nucleotide polymorphism (SNP) and phylogenetic analyses confirmed two major lineages concordant with the former Type S and Type C designations. The Type I and Type III strain groups are subtypes of Type S, and Type B strains are a subtype of Type C and not restricted to Bison species. We found that the genome-wide SNPs detected provided greater resolution between isolates than currently employed genotyping methods. Furthermore, the SNP used for IS1311 typing is not informative, as it is likely to have occurred after Type S and C strains diverged and does not assign all strains to the correct lineage. Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeat (MIRU-VNTR) differentiates Type S from Type C but provides limited resolution between isolates within these lineages and the polymorphisms detected do not necessarily accurately reflect the phylogenetic relationships between strains. WGS of passaged strains and coalescent analysis of the collection revealed a very high level of genetic stability, with the substitution rate estimated to be less than 0.5 SNPs per genome per year.This study clarifies the phylogenetic relationships between the previously described Map strain groups, and highlights the limitations of current genotyping techniques. Map isolates exhibit restricted genetic diversity and a substitution rate consistent with a monomorphic pathogen. WGS provides the ultimate level of resolution for differentiation between strains. However, WGS alone will not be sufficient for tracing and tracking Map infections, yet importantly it can provide a phylogenetic context for affirming epidemiological connections.


PubMed | Ludwig Maximilians University of Munich, University of Veterinary Medicine Hannover, Research Center Borstel, Cornell University and CNRS Infectiology and Public Health
Type: Journal Article | Journal: Innate immunity | Year: 2015

The distal compartments of the udder are the first to interact with invading pathogens. The regulatory and effector functions of two major teat regions [Frstenbergs rosette (FR); teat cistern (TC)] are largely unknown. The objective of this study was to establish an invitro model with explants of the FR and the TC to analyse their response towards Escherichia coli LPS and Staphylococcus aureus lipoteichoic acid (LTA). Quantitative stereological analysis confirmed differences in the cellular composition of FR and TC explants. Chemokine (CXCL8, CCL5, CCL20) and TNF- mRNA were expressed at low levels in both locations. Explant stimulation with LPS increased the mRNA abundance of all tested chemokines and TNF-. Stimulation with LTA only induced CCL20 and CXCL8. LPS- and LTA-stimulated explant supernatants contained CXCL8 and CXCL3. Supernatants significantly attracted neutrophils in vitro. Compared with TC, the FR showed high constitutive mRNA expression of S100 proteins (A8, A9, A12). In the TC, both LPS and LTA significantly induced S100A8, whereas S100A9 and S100A12 expression was only induced by LPS. The novel model system underpins the role of the teat for recognising pathogens and shaping a pathogen- and location-specific immune response.


PubMed | Scientific Institute of Public Health WIV ISP Site Ukkel, National Polytechnic Institute of Mexico and CNRS Infectiology and Public Health
Type: | Journal: Journal of theoretical biology | Year: 2015

Mycobacterium avium subsp. paratuberculosis (MAP) is the etiologic agent of paratuberculosis disease affecting ruminants worldwide. The aim of this study was to identify potential candidate antigens and epitopes by bio and immuno-informatic tools which could be later evaluated as vaccines and/or diagnosis. 110 protein sequences were selected from MAP K-10 genome database: 48 classified as putative enzymes involved in surface polysaccharide and lipopolysaccharide synthesis, as membrane associated and secreted proteins, 32 as conserved membrane proteins, and 30 as absent from other mycobacterial genomes. These 110 proteins were preliminary screened for Major Histocompatibility Complex (MHC) class II affinity and promiscuity using ProPred program. In addition, subcellular localization and host protein homology was analyzed. From these analyses, 23 MAP proteins were selected for a more accurate inmunoinformatic analysis (i.e. T cell and B cell epitopes analysis) and for homology with mycobacterial proteins. Finally, eleven MAP proteins were identified as potential candidates for further immunogenic evaluation: six proteins (MAP0228c, MAP1239c, MAP2232, MAP3080, MAP3131 and MAP3890) were identified as presenting potential T cell epitopes, while 5 selected proteins (MAP0232c, MAP1240c, MAP1738, MAP2239 and MAP3641c) harbored a large numbers of epitopes predicted to induce both cell- and antibody-mediated immune responses. Moreover, immunogenicity of selected epitopes from MAP1239c were evaluated in IFN- release assay. In summary, eleven M. avium subsp. paratuberculosis proteins were identified by in silico analysis and need to be further evaluated for their immunodiagnostic and vaccine potential in field and mice model.


PubMed | CNRS Infectiology and Public Health, Veterinary Control Institute and Firat University
Type: Journal Article | Journal: Iranian journal of veterinary research | Year: 2016

Q fever is a zoonotic disease that occurs worldwide and is caused by the obligate intracellular bacterium Coxiella burnetii. The aim of this study was to investigate the presence of C. burnetii infection in aborted sheep in eastern Turkey using PCR. A total of 200 fetuses were collected from aborted sheep belonging to 200 herds in different locations in the eastern part of Turkey. Foetal organ samples such as liver, spleen, lung and stomach were taken and the DNA was purified from two hundred pooled samples. PCR analysis of C. burnetii presence in infected organs was performed, and 4 samples (2%) were found positive. In addition, the pooled organ suspensions were inoculated to embryonated chicken eggs, and PCR analysis of yolk sacs showed C. burnetii DNA in 5 samples (2.5%). This study shows that C. burnetii infection has an important role in sheep abortions in eastern Anatolia region.


Mareks disease is a virus disease with worldwide distribution that causes major losses to poultry production. Vaccines against Mareks disease virus, an oncogenic alphaherpesvirus, reduce tumour formation but have no effect on virus shedding. Successful horizontal virus transmission is linked to the active viral replication in feather follicle epithelial cells of infected chickens, from which infectious viral particles are shed into the environment. The feather follicle epithelium is the sole tissue in which those infectious particles are produced and no in vitro cell-systems can support this highly efficient morphogenesis. We previously characterized embryonic stem-cell-derived keratinocytes, showing they display a marker-gene profile similar to skin keratinocytes, and therefore we tested their susceptibility to Mareks disease virus infection.We show herein that keratinocytes derived from chicken embryonic stem-cells are fully permissive to the replication of either non-pathogenic or pathogenic Mareks disease viruses. All viruses replicated on all three keratinocyte lines and kinetics of viral production as well as viral loads were similar to those obtained on primary cells. Morphogenesis studies were conducted on infected keratinocytes and on corneocytes, showing that all types of capsids/virions were present inside the cells, but extracellular viruses were absent.The keratinocyte lines are the first epithelial cell-line showing ectodermal specific markers supporting Mareks disease virus replication. In this in vitro model the replication lead to the production of cell-associated viral progeny. Further work will be devoted to the study of relationship between 3D differentiation of keratinocytes and Mareks disease virus replication.

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