Characterization of blood biomarkers in endurance horses by integrating miRNA and mRNA expression profiling

Characterization of blood biomarkers in endurance horses by integrating miRNA and mRNA expression profiling. 11. Dorothy Russel Havemeyer Foundation International Equine Genome Mapping Worksho

RNA silencing-targeted transcriptome of porcine alveolar macrophages upon infection with porcine reproductive and respiratory syndrome viruses (PRRSV) of different virulence

International audienc

Integrative genomics analysis of blood and microbiota data suggests a NAFLD-related disorder in SLAdd minipigs

International audienc

Efficiency of heterologous capture for targeted resequencing of the Major Histocompatibility Complex in Suidae and Tayassuidae

Sequence capture is a widespread and cost effective approach to resequence specific genomic regions on large sets of individuals. To date, this approach has mainly been used to target orthologous loci within the same species ('homologous' capture). Our aim was to test the efficiency of this method across closely or distantly related species ('heterologous' capture). Specifically, we focused on the MHC locus, which is one of the most dynamic regions of mammalian genomes, and a model to study host-pathogen coevolution. A 385K solid phase array (NimbleGen) encompassing the MHC was designed using the Sus scrofa Hp1a.0 haplotype as a reference (http://vega.sanger.ac.uk/index.html). Individuals from 9 species of Suidae (n=69) and 2 species of Tayassuidae (n=19) were selected for the study. Sets of 12 uniquely indexed sequencing libraries were prepared using Illumina kits, pooled, enriched, and sequenced on a HiSeq platform. In Suidae, the average values of coverage and specificity (% on target sequences) were respectively 86x and 32%. Results varied significantly across libraries, e.g. decreasing the number of cycles during PCR steps reduced the percentage of duplicate reads, but without improving specificity. On the other hand, in Tayassuidae both the coverage and the specificity showed lower efficiency. We can conclude that heterologous capture is a reliable technique at the level of Suidae, while in the case of Tayassuidae further optimization will be required to achieve better results. Other analyses are ongoing to test if this method could be suitable to study structural variation

CRB GADIE : centre de ressources biologiques pour la génomique des animaux domestiques et d'intérêt économique

National audienc

Susceptibility to Salmonella carrier-state: A possible Th2 response in susceptible chicks

Infection of chicken with Salmonella may lead to a carrier-state characterized by the persistence of bacteria in the ceca for a long period of time and result in their excretion in feces. This excretion is the source of contamination of their congeners and food. During infection, enterocytes are the primary target cells for Salmonella, the producers of soluble factors which launch immune response and cells which are reciprocally responsive to surrounding immune cells. This study used microarrays to compare the gene expression profile during carrier-state of enterocytes purified from infected and control chicks which are either resistant or susceptible to Salmonella Enteritidis carrier-state. In total, we identified 271 genes significantly differentially expressed with an absolute fold change greater than 1.5. A global analysis determined interaction networks between differentially regulated genes. Using an a priori approach, our analyses focused on differentially expressed genes which were transcriptionally linked to cytokines playing a major role in the fate of the immune response. The expression of genes transcriptionally linked to type I interferon and TGF-beta was down-regulated in infected chicks from both lines. Gene expression linked to the Th1 axis suggests the latter is inhibited in both lines. Finally, the expression of genes linked to IL-4, IL-5 and IL-13 indicates that susceptibility to carrier-state could be associated with a Th2 bias. Overall, these results highlight that the response to Salmonella during the acute phase and carrier-state is different and that enterocytes play a central role in this response. (C) 2014 Elsevier B.V. All rights reserved

Lung neonatal responses to respiratory syncytial virus reveal deficiencies in dendritic cells and type I interferon in a mouse model of airway enhanced disease

International audienc

Kinetic characterization of PB1-F2-mediated immunopathology during highly pathogenic avian H5N1 influenza virus infection.

Chantier qualité GAInternational audienceThe PB1-F2 protein encoded by influenza A viruses can contribute to virulence, a feature that is dependent of its sequence polymorphism. Whereas PB1-F2 from some H1N1 viruses were shown to exacerbate the inflammatory response within the airways, the contribution of PB1-F2 to highly pathogenic avian influenza virus (HPAIV) virulence in mammals remains poorly described. Using a H5N1 HPAIV strain isolated from duck and its PB1-F2 knocked-out mutant, we characterized the dynamics of PB1-F2-associated host response in a murine model of lethal pneumonia. The mean time of death was 10 days for the two viruses, allowing us to perform global transcriptomic analyses and detailed histological investigations of the infected lungs at multiple time points. At day 2 post-infection (pi), while no histopathological lesion was observed, PB1-F2 expression resulted in a significant inhibition of cellular pathways involved in macrophage activation and in a transcriptomic signature suggesting that it promotes damage to the epithelial barrier. At day 4 pi, the gene profile associated with PB1-F2 expression revealed dysfunctions in NK cells activity. At day 8 pi, PB1-F2 expression was strongly associated with increased transcription of genes encoding chemokines and cytokines implicated in the recruitment of granulocytes, as well as expression of a number of genes encoding enzymes expressed by neutrophils. These transcriptomic data were fully supported by the histopathological analysis of the mice lungs which evidenced more severe inflammatory lesions and enhanced recruitment of neutrophils in the context of PB1-F2 expression, and thus provided a functional corroboration to the insight obtained in this work. In summary, our study shows that PB1-F2 of H5N1 HPAIV markedly influences the expression of the host transcriptome in a different way than its H1N1 counterparts: H5N1 PB1-F2 first delays the initial immune response but increases the pulmonary inflammatory response during the late stages of infection