Lung progenitors from lambs can differentiate into specialized alveolar or bronchiolar epithelial cells.

26International audienceBACKGROUND: Airways progenitors may be involved in embryogenesis and lung repair. The characterization of these important populations may enable development of new therapeutics to treat acute or chronic lung disease. In this study, we aimed to establish the presence of bronchioloalveolar progenitors in ovine lungs and to characterize their potential to differentiate into specialized cells. RESULTS: Lung cells were studied using immunohistochemistry on frozen sections of the lung. Immunocytochemistry and flow cytometry were conducted on ex-vivo derived pulmonary cells. The bronchioloalveolar progenitors were identified by their co-expression of CCSP, SP-C and CD34. A minor population of CD34pos/SP-Cpos/CCSPpos cells (0.33% +/- 0.31) was present ex vivo in cell suspensions from dissociated lungs. Using CD34 magnetic positive-cell sorting, undifferentiated SP-Cpos/CCSPpos cells were purified (>80%) and maintained in culture. Using synthetic media and various extracellular matrices, SP-Cpos/CCSPpos cells differentiated into either club cells (formerly named Clara cells) or alveolar epithelial type-II cells. Furthermore, these ex vivo and in vitro derived bronchioloalveolar progenitors expressed NANOG, OCT4 and BMI1, specifically described in progenitors or stem cells, and during lung development. CONCLUSIONS: We report for the first time in a large animal the existence of bronchioloalveolar progenitors with dual differentiation potential and the expression of specialized genes. These newly described cell population in sheep could be implicated in regeneration of the lung following lesions or in development of diseases such as cancers

Requirement of Caprine Arthritis Encephalitis VirusvifGene forin VivoReplication

AbstractReplication ofvif-caprine arthritis encephalitis virus (CAEV) is highly attenuated in primary goat synovial membrane cells and blood-derived macrophages compared to the wild-type (wt) virus. We investigated the requirement for CAEV Vif forin vivoreplication and pathogenicity in goats by intra-articular injection of either infectious proviral DNA or viral supernatants. Wild-type CAEV DNA or virus inoculation induced persistent infection resulting in severe inflammatory arthritic lesions in the joints. We were unable to detect any sign of virus replication invif-CAEV DNA inoculated goats, whilevif-CAEV virus inoculation resulted in the seroconversion of the goats. However, virus isolation and RT-PCR analyses on blood-derived macrophage cultures remained negative throughout the experiment as well as in joint or lymphoid tissues taken at necropsy. No pathologic lesions could be observed in joint tissue sections examined at necropsy. Goats inoculated with thevif-virus demonstrated no protection against a pathogenic virus challenge. These results demonstrate that CAEV Vif is absolutely required for efficientin vivovirus replication and pathogenicity and provide additional evidence that live attenuated lentiviruses have to establish a persistent infection to induce efficient protective immunity

Endocrine and environmental aspects of sex differentiation in gonochoristic fish

International audienc

Etude des effets de traitements d'inversion sexuelle par les stéroïdes et la température chez les poissons

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Endocrine and environmental aspects of sex differentiation in fish

International audienc

Séquençage d'étiquettes (EST) de bovins, porcins, poulet et truite à partir de banques d'ADNc à faible niveau de redondance

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La fièvre de la vallée du rift : prochaine maladie infectieuse émergente en France ?

La fièvre de la vallée du rift (FVR) est une arbovirose exotique présente en Afrique, due à un bunyavirus. Il s'agit d'une zoonose redoutable : l'homme se contamine surtout au contact des ruminants malades, mais aussi par piqûre de moustique infecté. En raison du grand nombre de moustiques capables de véhiculer le virus, dont certains sont présents en France et en Europe, du réchauffement climatique et de la globalisation des échanges (population, denrées alimentaires etc...), la FVR est considérée comme susceptible d'émerger au Nord de la Méditérranée. La maladie se traduit chez le mouton, l'espèce la plus sensible, les chèvres et les bovins par des septicémies et une forte mortalité chez les animaux très jeunes, une hépatite nécrosante chez les animaux plus âgés et surtout par des flambées d'avortements. Chez l'homme, l'expression clinique va de l'absence de signes à une fièvre hémorragique en passant par un syndrome pseudo-grippal, une hépatite, etc... ; la mortalité est proche de 1%. Le diagnostic est réalisé par isolement du virus ou recherche de l'ARN viral par RT-PCR, et par la mise en évidence des anticorps par ELISA ou séroneutralisation. Si la lutte contre les vecteurs et les mesures de police sanitaire sont importantes, le seul moyen efficace de contrôler et prévenir la FVR reste la vaccination des animaux sensibles

In between: Gypsy in Drosophila melanogaster reveals new insights into endogenous retrovirus evolution

Retroviruses are RNA viruses that are able to synthesize a DNA copy of their genome and insert it into a chromosome of the host cell. Sequencing of different eukaryote genomes has revealed the presence of many such endogenous retroviral sequences. The mechanisms by which these retroviral sequences have colonized the genome are still unknown, and the endogenous retrovirus gypsy of Drosophila melanogaster is a powerful experimental model for deciphering this process in vivo. Gypsy is expressed in a layer of somatic cells, and then transferred into the oocyte by an unknown mechanism. This critical step is the start of the endogenization process. Moreover gypsy has been shown to have infectious properties, probably due to its envelope gene acquired from a baculovirus. Recently we have also shown that gypsy maternal transmission is reduced in the presence of the endosymbiotic bacterium Wolbachia. These studies demonstrate that gypsy is a unique and powerful model for understanding the endogenization of retroviruses

Le contrôle du sexe phénotypique chez les poissons

National audienceThis paper briefly discusses the genetic determination of sex in fishes, and the effects of hormones and external factors on phenotypic sex. Current research at the Institut National de la Recherche Agronomique, France on the subject, and future lines of research, are also considered.L'intérêt du contrôle phénotypique du sexe chez les poissons est essentiellement pratique. Il s'agit de prévenir par monosexage les reproductions spontanées, de bénéficier de caractéristiques biologiques spécifiques à un sexe, d'optimiser la gestion des cheptels de géniteurs... Les voies actuelles de contrôle du sexe phénotypique sont de trois types : génétique, endocrinien et le contrôle par des facteurs externes. Les recherches en cours s'intéressent aux périodes et aux cinétiques de différenciation ou d'inversion sexuelle en relation avec l'environnement. Les corrélations endocriniennes sont recherchées en vue d'identifier des déterminants physiologiques. Les recherches prospectives visent à connaître les régulations physiologiques avec pour objectif de limiter ou même de supprimer les traitements hormonaux actuellement utilisés