19 research outputs found
Toll-like receptor 4, but not neutrophil extracellular Traps, Promote IFN Type I expression to enhance Th2 responses to Nippostrongylus brasiliensis
The induction of Th2 responses is thought to be multifactorial, and emerge from specific pathways distinct from those associated with antagonistic antibacterial or antiviral Th1 responses. Here, we show that the recognition of non-viable Nippostrongylus brasiliensis (Nb) in the skin induces a strong recruitment of monocytes and neutrophils and the release of neutrophil extracellular traps (NETs). Nb also activates toll-like receptor 4 (TLR4) signaling with expression of Ifnb transcripts in the skin and the development of an IFN type I signature on helminth antigen-bearing dendritic cells in draining lymph nodes. Co-injection of Nb together with about 10,000 Gram-negative bacteria amplified this TLR4-dependent but NET-independent IFN type I response and enhanced the development of Th2 responses. Thus, a limited activation of antibacterial signaling pathways is able to boost antihelminthic responses, suggesting a role for bacterial sensing in the optimal induction of Th2 immunity
Identification and characterization of DSP1 protein partners in drosophila embryo
Chez les eucaryotes pluricellulaires, la diffĂ©renciation des cellules repose en partie sur lâactivation oula rĂ©pression des gĂšnes. Les profils dâexpression gĂ©nique mis en place vont perdurer dâune gĂ©nĂ©rationcellulaire Ă lâautre. Ce phĂ©nomĂšne met en jeu des mĂ©canismes Ă©pigĂ©nĂ©tiques qui remodĂšlentlocalement la structure de la chromatine. Chez Drosophila melanogaster, les protĂ©ines des groupesPolycomb (PcG) et Trithorax (TrxG) participent au maintien du profil dâexpression des gĂšnes au coursdu dĂ©veloppement. Les protĂ©ines PcG maintiennent les gĂšnes rĂ©primĂ©s tandis que les protĂ©ines TrxGmaintiennent les gĂšnes activĂ©s. Une troisiĂšme classe de protĂ©ines nommĂ©e Enhancers of Trithoraxand Polycomb (ETP) module lâactivitĂ© des PcG et TrxG. Dorsal Switch Protein 1 (DSP1) est uneprotĂ©ine HMGB (High Mobility Group B) classĂ©e comme une ETP. Par tamisage molĂ©culaire, nousavions montrĂ© que la protĂ©ine DSP1 Ă©tait prĂ©sente au sein de complexes de poids molĂ©culaire de 100kDa Ă 1 MDa. Le travail de thĂšse prĂ©sentĂ© ici a pour but dâidentifier les partenaires de la protĂ©ineDSP1 dans lâembryon et de mieux connaĂźtre les propriĂ©tĂ©s biochimiques de DSP1. PremiĂšrement, jâaimis en place puis effectuĂ© lâimmunopurification des complexes contenant DSP1 dans des extraitsprotĂ©iques embryonnaires. Cette approche nous a permis dâidentifier 23 partenaires putatifs de laprotĂ©ine DSP1. Parmi ces protĂ©ines, nous avons identifiĂ© la protĂ©ine Rm62 qui est une ARN hĂ©licaseĂ boĂźte DEAD. Les relations biologiques entre DSP1 et Rm62 ont Ă©tĂ© prĂ©cisĂ©es. DeuxiĂšmement, jâaidĂ©terminĂ©, par une approche biochimique, de nouvelles caractĂ©ristiques physico-chimiques de laprotĂ©ine DSP1.In multicellular organism, the identity of cell is determined by several factors playing on genesexpression. Once established, the gene expression pattern is transmitted to daughter cells through aprocess involving epigenetic mechanisms that locally reshape the structure of chromatin. In Drosophilamelanogaster, the Polycomb (PcG) and trithorax (trxG) group genes are involved in the maintenanceof gene expression profile during development. Inside multimeric complexes, PcG proteins maintaingenes in repressed state whereas TrxG maintain genes active. A third class of proteins, calledEnhancers of Trithorax and Polycomb, regulate PcG and TrxG activities. Dorsal Switch Protein 1(DSP1) is a High Mobility Group B protein acting as an ETP. But DSP1 has not yet been identified inPcG or TrxG complexes. On the basis of gel filtration analysis of protein complexes in embryo nuclearextracts, it appears that the majority of DSP1 is present in complex(es) from 100 kDa to 1MDa. Aimsof present work are the identification of DSP1 protein partners in drosophila embryo and thecharacterization of biochemical properties of DSP1. Firstly, I used immunopurification from drosophilaembryonic nuclear extracts. The proteins purified with DSP1 were characterized through sequencingof peptides from individual protein bands by mass spectrometry. Among identified proteins, wefocused on the DEAD Box RNA helicase, Rm62. The role of interaction between DSP1 and Rm62 hasbeen characterized. Secondly, I have identified a new physicochemical aspect of DSP1 protein
Identification et caractérisation des partenaires protéiques de DSP1 chez Drosophila melanogaster
In multicellular organism, the identity of cell is determined by several factors playing on genesexpression. Once established, the gene expression pattern is transmitted to daughter cells through aprocess involving epigenetic mechanisms that locally reshape the structure of chromatin. In Drosophilamelanogaster, the Polycomb (PcG) and trithorax (trxG) group genes are involved in the maintenanceof gene expression profile during development. Inside multimeric complexes, PcG proteins maintaingenes in repressed state whereas TrxG maintain genes active. A third class of proteins, calledEnhancers of Trithorax and Polycomb, regulate PcG and TrxG activities. Dorsal Switch Protein 1(DSP1) is a High Mobility Group B protein acting as an ETP. But DSP1 has not yet been identified inPcG or TrxG complexes. On the basis of gel filtration analysis of protein complexes in embryo nuclearextracts, it appears that the majority of DSP1 is present in complex(es) from 100 kDa to 1MDa. Aimsof present work are the identification of DSP1 protein partners in drosophila embryo and thecharacterization of biochemical properties of DSP1. Firstly, I used immunopurification from drosophilaembryonic nuclear extracts. The proteins purified with DSP1 were characterized through sequencingof peptides from individual protein bands by mass spectrometry. Among identified proteins, wefocused on the DEAD Box RNA helicase, Rm62. The role of interaction between DSP1 and Rm62 hasbeen characterized. Secondly, I have identified a new physicochemical aspect of DSP1 protein.Chez les eucaryotes pluricellulaires, la diffĂ©renciation des cellules repose en partie sur lâactivation oula rĂ©pression des gĂšnes. Les profils dâexpression gĂ©nique mis en place vont perdurer dâune gĂ©nĂ©rationcellulaire Ă lâautre. Ce phĂ©nomĂšne met en jeu des mĂ©canismes Ă©pigĂ©nĂ©tiques qui remodĂšlentlocalement la structure de la chromatine. Chez Drosophila melanogaster, les protĂ©ines des groupesPolycomb (PcG) et Trithorax (TrxG) participent au maintien du profil dâexpression des gĂšnes au coursdu dĂ©veloppement. Les protĂ©ines PcG maintiennent les gĂšnes rĂ©primĂ©s tandis que les protĂ©ines TrxGmaintiennent les gĂšnes activĂ©s. Une troisiĂšme classe de protĂ©ines nommĂ©e Enhancers of Trithoraxand Polycomb (ETP) module lâactivitĂ© des PcG et TrxG. Dorsal Switch Protein 1 (DSP1) est uneprotĂ©ine HMGB (High Mobility Group B) classĂ©e comme une ETP. Par tamisage molĂ©culaire, nousavions montrĂ© que la protĂ©ine DSP1 Ă©tait prĂ©sente au sein de complexes de poids molĂ©culaire de 100kDa Ă 1 MDa. Le travail de thĂšse prĂ©sentĂ© ici a pour but dâidentifier les partenaires de la protĂ©ineDSP1 dans lâembryon et de mieux connaĂźtre les propriĂ©tĂ©s biochimiques de DSP1. PremiĂšrement, jâaimis en place puis effectuĂ© lâimmunopurification des complexes contenant DSP1 dans des extraitsprotĂ©iques embryonnaires. Cette approche nous a permis dâidentifier 23 partenaires putatifs de laprotĂ©ine DSP1. Parmi ces protĂ©ines, nous avons identifiĂ© la protĂ©ine Rm62 qui est une ARN hĂ©licaseĂ boĂźte DEAD. Les relations biologiques entre DSP1 et Rm62 ont Ă©tĂ© prĂ©cisĂ©es. DeuxiĂšmement, jâaidĂ©terminĂ©, par une approche biochimique, de nouvelles caractĂ©ristiques physico-chimiques de laprotĂ©ine DSP1
Identification et caractérisation des partenaires protéiques de DSP1 chez Drosophila melanogaster
Chez les eucaryotes pluricellulaires, la différenciation des cellules repose en partie sur l activation oula répression des gÚnes. Les profils d expression génique mis en place vont perdurer d une générationcellulaire à l autre. Ce phénomÚne met en jeu des mécanismes épigénétiques qui remodÚlentlocalement la structure de la chromatine. Chez Drosophila melanogaster, les protéines des groupesPolycomb (PcG) et Trithorax (TrxG) participent au maintien du profil d expression des gÚnes au coursdu développement. Les protéines PcG maintiennent les gÚnes réprimés tandis que les protéines TrxGmaintiennent les gÚnes activés. Une troisiÚme classe de protéines nommée Enhancers of Trithoraxand Polycomb (ETP) module l activité des PcG et TrxG. Dorsal Switch Protein 1 (DSP1) est uneprotéine HMGB (High Mobility Group B) classée comme une ETP. Par tamisage moléculaire, nousavions montré que la protéine DSP1 était présente au sein de complexes de poids moléculaire de 100kDa à 1 MDa. Le travail de thÚse présenté ici a pour but d identifier les partenaires de la protéineDSP1 dans l embryon et de mieux connaßtre les propriétés biochimiques de DSP1. PremiÚrement, j aimis en place puis effectué l immunopurification des complexes contenant DSP1 dans des extraitsprotéiques embryonnaires. Cette approche nous a permis d identifier 23 partenaires putatifs de laprotéine DSP1. Parmi ces protéines, nous avons identifié la protéine Rm62 qui est une ARN hélicaseà boßte DEAD. Les relations biologiques entre DSP1 et Rm62 ont été précisées. DeuxiÚmement, j aidéterminé, par une approche biochimique, de nouvelles caractéristiques physico-chimiques de laprotéine DSP1.In multicellular organism, the identity of cell is determined by several factors playing on genesexpression. Once established, the gene expression pattern is transmitted to daughter cells through aprocess involving epigenetic mechanisms that locally reshape the structure of chromatin. In Drosophilamelanogaster, the Polycomb (PcG) and trithorax (trxG) group genes are involved in the maintenanceof gene expression profile during development. Inside multimeric complexes, PcG proteins maintaingenes in repressed state whereas TrxG maintain genes active. A third class of proteins, calledEnhancers of Trithorax and Polycomb, regulate PcG and TrxG activities. Dorsal Switch Protein 1(DSP1) is a High Mobility Group B protein acting as an ETP. But DSP1 has not yet been identified inPcG or TrxG complexes. On the basis of gel filtration analysis of protein complexes in embryo nuclearextracts, it appears that the majority of DSP1 is present in complex(es) from 100 kDa to 1MDa. Aimsof present work are the identification of DSP1 protein partners in drosophila embryo and thecharacterization of biochemical properties of DSP1. Firstly, I used immunopurification from drosophilaembryonic nuclear extracts. The proteins purified with DSP1 were characterized through sequencingof peptides from individual protein bands by mass spectrometry. Among identified proteins, wefocused on the DEAD Box RNA helicase, Rm62. The role of interaction between DSP1 and Rm62 hasbeen characterized. Secondly, I have identified a new physicochemical aspect of DSP1 protein.ORLEANS-SCD-Bib. electronique (452349901) / SudocSudocFranceF
Rm62, a DEAD box RNA helicase, complexes with DSP1 in Drosophila embryos
International audienceTwo main classes of proteins, Polycomb group (PcG) and Trithorax group (TrxG), play a key role in the regulation of homeotic genes. These proteins act in multimeric complexes to remodel chromatin. A third class of proteins named Enhancers of Trithorax and Polycomb (ETP) modulates the activity of TrxG and PcG, but their role remains largely unknown. We previously identified an HMGB-like protein, DSP1 (Dorsal Switch Protein 1), which was classified as an ETP. Preliminary studies have revealed that DSP1 is involved in multimeric complexes. Here we identify a DEAD-box RNA helicase, Rm62, as partner of DSP1 in a 250-kDa complex. Coimmunoprecipitation assays performed on embryo extracts indicate that DSP1 and Rm62 are associated in 3- to 12-h embryos. Furthermore, DSP1 and Rm62 colocalize on polytene chromosomes. Consistent with these results, a mutation in Rm62 enhances a null mutation of dsp1 and also mutations of trxG or PcG, suggesting that Rm62 has characteristics of an ETP. We show here for the first time that an RNA helicase is involved in the maintenance of homeotic genes
Distribution tissulaire
Objectif : Décrire la distribution du méprobamate dans
différents tissus et fluides biologiques collectés lors de
l'autopsie concernant huit cas de décÚs pour lesquels le
méprobamate a été identifié dans le sang
périphérique.
Méthodes : Les prélÚvements autopsiques disponibles
étaient le plus souvent le sang périphérique, le sang cardiaque,
l'humeur vitrée, la bile, le foie, le rein, le poumon, le coeur et le
cerveau. Les échantillons (fluides et homogénats tissulaires)
étaient analysés par LC-MSn à trappe d'ions, aprÚs
extraction liquide-liquide en présence de carisoprodol (étalon
interne).
Résultats : Les concentrations de méprobamate dans le sang
périphérique variaient de 9 à 160 mg/L. Les coefficients de
distribution post-mortem du méprobamate, exprimés par le rapport [concentration
dans le tissu (mg/kg) ou fluide d'intĂ©rĂȘt (mg/L)]/[concentration
dans le sang périphérique (mg/L)], étaient de 0,97 pour le sang
cardiaque (n=8), 0,83 pour l'humeur vitrée (n=6), 1,16 pour la bile
(n=8), 2,63 pour le foie (n=6), 1,82 pour le rein (n=8), 1,81 pour le coeur
(n=8), 1,83 pour le cerveau (n=8) et 1,74 pour le poumon (n=8). Les
coefficients de variation associés à ces moyennes étaient tous
infĂ©rieurs Ă 25â%, exceptĂ© pour le foie (31â%).
Conclusion : Avec des coefficients de distribution moyens proches
de 1, le méprobamate ne semble pas s'accumuler dans l'humeur vitrée
et la bile. Dans les autres tissus, ces coefficients varient de 1,7 Ă
2,6, objectivant ainsi une distribution tissulaire modérée, en
accord avec le volume apparent de distribution peu élevé du
méprobamate (0,7 L/kg). En dépit du nombre limité de cas
étudiés, la variabilité inter-individuelle relativement peu
importante de la distribution tissulaire de méprobamate pourrait
théoriquement suggérer l'utilisation des concentrations tissulaires
post-mortem en vue d'une estimation des concentrations dans le sang
pĂ©riphĂ©rique, lorsque cette matrice n'est pas disponible Ă
l'autopsie. Pour ĂȘtre confirmĂ©s, ces rĂ©sultats nĂ©cessitent
d'ĂȘtre complĂ©tĂ©s dans une plus large Ă©tude
Drosophila C virus systemic infection leads to intestinal obstruction
Drosophila C virus (DCV) is a positive-sense RNA virus belonging to the Dicistroviridae family. This natural pathogen of the model organism Drosophila melanogaster is commonly used to investigate antiviral host defense in flies, which involves both RNA interference and inducible responses. Although lethality is used routinely as a readout for the efficiency of the antiviral immune response in these studies, virus-induced pathologies in flies still are poorly understood. Here, we characterize the pathogenesis associated with systemic DCV infection. Comparison of the transcriptome of flies infected with DCV or two other positive-sense RNA viruses, Flock House virus and Sindbis virus, reveals that DCV infection, unlike those of the other two viruses, represses the expression of a large number of genes. Several of these genes are expressed specifically in the midgut and also are repressed by starvation. We show that systemic DCV infection triggers a nutritional stress in Drosophila which results from intestinal obstruction with the accumulation of peritrophic matrix at the entry of the midgut and the accumulation of the food ingested in the crop, a blind muscular food storage organ. The related virus cricket paralysis virus (CrPV), which efficiently grows in Drosophila, does not trigger this pathology. We show that DCV, but not CrPV, infects the smooth muscles surrounding the crop, causing extensive cytopathology and strongly reducing the rate of contractions. We conclude that the pathogenesis associated with systemic DCV infection results from the tropism of the virus for an important organ within the foregut of dipteran insects, the crop. IMPORTANCE: DCV is one of the few identified natural viral pathogens affecting the model organism Drosophila melanogaster. As such, it is an important virus for the deciphering of host-virus interactions in insects. We characterize here the pathogenesis associated with DCV infection in flies and show that it results from the tropism of the virus for an essential but poorly characterized organ in the digestive tract, the crop. Our results may have relevance for other members of the Dicistroviridae, some of which are pathogenic to beneficial or pest insect species
Cytokine Diedel and a viral homologue suppress the IMD pathway in Drosophila
International audienceno abstrac