The relationship between CD4+CD25+CD127- regulatory T cells and inflammatory response and outcome during shock states

International audienceINTRODUCTION: Although regulatory T lymphocytes (Tregs) have a pivotal role in preventing autoimmune diseases and limiting chronic inflammatory conditions, they may also block beneficial immune responses by preventing sterilizing immunity to certain pathogens. METHODS: To determine whether naturally occurring Treg cells have a role in inflammatory response and outcome during shock state we conducted an observational study in two adult ICUs from a university hospital. Within 12 hours of admission, peripheral whole blood was collected for the measurement of cytokines and determination of lymphocyte count. Sampling was repeated at day three, five and seven. Furthermore, an experimental septic shock was induced in adult Balb/c mice through caecal ligation and puncture. RESULTS: Forty-three patients suffering from shock (26 septic, 17 non septic), and 7 healthy volunteers were included. The percentage of Tregs increased as early as 3 days after the onset of shock, while their absolute number remained lower than in healthy volunteers. A similar pattern of Tregs kinetics was found in infected and non infected patients. Though there was an inverse correlation between severity scores and Tregs percentage, the time course of Tregs was similar between survivors and non survivors. No relation between Tregs and cytokine concentration was found. In septic mice, although there was a rapid increase in Treg cells subset among splenocytes, antibody-induced depletion of Tregs before the onset of sepsis did not alter survival. CONCLUSIONS: These data argue against a determinant role of Tregs in inflammatory response and outcome during shock states

Follicular Proinflammatory Cytokines and Chemokines as Markers of IVF Success

Cytokines are key modulators of the immune system and also contribute to regulation of the ovarian cycle. In this study, Bender MedSystems FlowCytomix technology was used to analyze follicular cytokines (proinflammatory: IL-1β, IL-6, IL-18, IFN-γ, IFN-α, TNF-α, IL-12, and IL-23;, and anti-inflammatory: G-CSF), chemokines (MIP-1α, MIP-1β, MCP-1, RANTES, and IL-8), and other biomarkers (sAPO-1/Fas, CD44(v6)) in 153 women undergoing in vitro fertilization (IVF). Cytokine origin was studied by mRNA analysis of granulosa cells. Higher follicular MIP-1α and CD44(v6) were found to correlate with polycystic ovary syndrome, IL-23, INF-γ, and TNF-α with endometriosis, higher CD44(v6) but lower IL-β and INF-α correlated with tubal factor infertility, and lower levels of IL-18 and CD44(v6) characterized unexplained infertility. IL-12 positively correlated with oocyte fertilization and embryo development, while increased IL-18, IL-8, and MIP-1β were associated with successful IVF-induced pregnancy

Relating Habitat and Climatic Niches in Birds

Predicting species' responses to the combined effects of habitat and climate changes has become a major challenge in ecology and conservation biology. However, the effects of climatic and habitat gradients on species distributions have generally been considered separately. Here, we explore the relationships between the habitat and thermal dimensions of the ecological niche in European common birds. Using data from the French Breeding Bird Survey, a large-scale bird monitoring program, we correlated the habitat and thermal positions and breadths of 74 bird species, controlling for life history traits and phylogeny. We found that cold climate species tend to have niche positions in closed habitats, as expected by the conjunction of the biogeographic history of birds' habitats, and their current continent-scale gradients. We also report a positive correlation between thermal and habitat niche breadths, a pattern consistent with macroecological predictions concerning the processes shaping species' distributions. Our results suggest that the relationships between the climatic and habitat components of the niche have to be taken into account to understand and predict changes in species' distributions

Back from a Predicted Climatic Extinction of an Island Endemic: A Future for the Corsican Nuthatch

The Corsican Nuthatch (Sitta whiteheadi) is red-listed as vulnerable to extinction by the IUCN because of its endemism, reduced population size, and recent decline. A further cause is the fragmentation and loss of its spatially-restricted favourite habitat, the Corsican pine (Pinus nigra laricio) forest. In this study, we aimed at estimating the potential impact of climate change on the distribution of the Corsican Nuthatch using species distribution models. Because this species has a strong trophic association with the Corsican and Maritime pines (P. nigra laricio and P. pinaster), we first modelled the current and future potential distribution of both pine species in order to use them as habitat variables when modelling the nuthatch distribution. However, the Corsican pine has suffered large distribution losses in the past centuries due to the development of anthropogenic activities, and is now restricted to mountainous woodland. As a consequence, its realized niche is likely significantly smaller than its fundamental niche, so that a projection of the current distribution under future climatic conditions would produce misleading results. To obtain a predicted pine distribution at closest to the geographic projection of the fundamental niche, we used available information on the current pine distribution associated to information on the persistence of isolated natural pine coppices. While common thresholds (maximizing the sum of sensitivity and specificity) predicted a potential large loss of the Corsican Nuthatch distribution by 2100, the use of more appropriate thresholds aiming at getting closer to the fundamental distribution of the Corsican pine predicted that 98% of the current presence points should remain potentially suitable for the nuthatch and its range could be 10% larger in the future. The habitat of the endemic Corsican Nuthatch is therefore more likely threatened by an increasing frequency and intensity of wildfires or anthropogenic activities than by climate change

Expression de tétraspanines et d'intégrines B1, et immunomodulation dans le cancer du poumon

Tetraspans associate with integrins in multimolecular complexes on the surface ofvarious cell types and are involved in numerous cell functions and notably in tumour invasion. The expression of tetraspans and [beta]1 integrins has been studied here in lung cancer on tumoral cell lines and on normal and tumoral pulmonary tissue samples. The influence of a chelator and of 4 cytokines on the expression of the molecules tested was also studied. The indirect immunofluorescence techniques used allowed flow cytometry and/or UV-lightmicroscopy analysis. Determination of cytokines secretion patterns was obtained from different celllines by a'cytokine array technique. Our results show an important heterogeneity in the expression of the molecules studiedand in the factors secreted by cells of the different cell lines, and support the involvement of CD9, CD82, CD151 and of CD29 in lung cancer. Moreover, expression of the molecules tested and adequate cell contacts seem to\ strongly rely on divalent cations availability. In conclusion, the immunomodulation of tetraspans and [bêta] 1 integrins expressed by pulmonary epithelial tumoral cells, by immunosuppressive cytokines or cytokines involved in the inflammatory and/or Th1 responses supports the major role of tumoral microenvironnement in expression ofthese molecules.Les tétraspanines s'associent, entre autres avec des intégrines, dans un réseau multimoléculaire à la surface de nombreux types cellulaires, et interviennent dans de multiples fonctions cellulaires et notamment dans le processus d'invasion tumorale. Dans cette étude l'expression de tétraspanines et d'intégrines [bêta]1 a été explorée dans le cadre du cancer du poumon, au niveau de cellules de lignées tumoral,es et d'échantillons de tissu sain et tumoral. L'influence d'un chélateur et de 4 cytokines sur l'expression de ces marqueurs a également été étudiée. Les techniques d'immunofluorescence indirecte utilisées ont permis une analyse en cytométrie de flux et/ou en microscopie UV. Les profils de sécrétion cytokinique de lignées cellulaires ont enfin été déterminés par une technique de cytokine array. Nos résultats montrent une grande hétérogénéité, tant au niveau de l'expression des molécules étudiées qu'au niveau des facteurs sécrétés par les cellules des différentes lignées tumorales étudiées, et confirment l'implication de CD9, CD82, CD151 et de CD29 dans le cancer du poumon. Les cations divalents apparaissent de plus indispensables à l'expression membranaire des molécules étudiées et à la formation de contacts intercellulaires stables. En conclusion, l'immunomodulation des tétraspanines et des intégrines [bêta]1, exprimées par les cellules épithéliales pulmonaires tumorales, par des cytokines immunosuppressives ou impliquées dans les réponses inflammatoires et/ou Th1 confirme l'importance du microenvironnement tumoral dans l'expression de ces molécules

Prédire l'impact potentiel des changements climatiques sur la distribution et la diversité des oiseaux européens

Les conséquences du changement climatique actuel sur la biodiversité font l objet de nombreuses études depuis la fin des années 1990. Certaines d entre elles ont mis en évidence un déplacement de l aire de distribution des espèces. Or, les changements climatiques prédits pour la fin du siècle devraient s accélérer. L objectif de la thèse était de prédire l impact potentiel de ces changements climatiques futurs sur la distribution et la diversité des oiseaux européens. Une première partie de mes travaux a porté sur des aspects méthodologiques ayant pour objectif l amélioration des prédictions d aires de distribution actuelles. Je me suis ensuite intéressée aux problèmes pouvant résulter de la projection sous scénario futur, lorsque la niche actuelle est biaisée, mais également à l importance de considérer les capacités de dispersion des espèces. Dans un deuxième temps, l application de ces différentes méthodes au niveau monospécifique m a permis de mettre en évidence que la Sittelle corse devrait plus souffrir de la destruction de son habitat que des changements climatiques. Au niveau multispécifique, l impact des changements globaux devrait être très important sur les aires de reproduction de l ensemble des oiseaux terrestres nicheurs européens ainsi que sur les aires d hivernage sub-sahariennes des passereaux européens. A partir de ces prédictions pour l ensemble d un groupe sur toute l Europe, l étude des assemblages d espèces révèle que les assemblages futurs sur tout le bassin méditerranéen ne seront analogues à aucun assemblage actuel. Enfin, l étude portant sur l évolution prédite de diversité fonctionnelle s avère complémentaire de celle sur la richesse spécifiquePARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

Expression de tétraspanines et d'intégrines B1, et immunomodulation dans le cancer du poumon

Les tétraspanines s'associent, entre autres avec des intégrines, dans un réseau multimoléculaire à la surface de nombreux types cellulaires, et interviennent dans de multiples fonctions cellulaires et notamment dans le processus d'invasion tumorale. Dans cette étude l'expression de tétraspanines et d'intégrines (31 a été explorée dans le cadre du cancer du poumon, au niveau de cellules de lignées tumoral,es et d'échantillons de tissu sain et tumoral. L'influence d'un chélateur et de 4 cytokines sur l'expression de ces marqueurs a également été étudiée. Les techniques d'immunofluorescence indirecte utilisées ont permis une analyse en cytométrie de flux et/ou en microscopie UV. Les profils de sécrétion cytokinique de lignées cellulaires ont enfin été déterminés par une technique de cytokine array. Nos résultats montrent une grande hétérogénéité, tant au niveau de l'expression des molécules étudiées qu'au niveau des facteurs sécrétés par les cellules des différentes lignées tumorales étudiées, et confirment l'implication de CD9, CD82, CD151 et de CD29 dans le cancer du poumon. Les cations divalents apparaissent de plus indispensables à l'expression membranaire des molécules étudiées et à la formation de contacts intercellulaires stables. En conclusion, l'immunomodulation des tétraspanines et des intégrines (31, exprimées par les cellules épithéliales pulmonaires tumorales, par des cytokines immunosuppressives ou impliquées dans les réponses inflammatoires et/ou Th1 confirme l'importance du microenvironnement tumoral dans l'expression de ces molécules.NANCY1-SCD Medecine (545472101) / SudocSudocFranceF

Predictive distribution models applied to satellite tracks: modelling the western African winter range of European migrant Black Storks Ciconia nigra

International audiencePredictive distribution models generally use data from multiple individuals each associated with a unique observation location, coupled with environmental parameters, to define the overall suitable area where the species could occur. Whether the use of multiple locations from few individuals is similarly efficient to model species distribution is not yet known. If so, the method could bring valuable inputs to identify priority conservation areas for rare or elusive species, especially those large vertebrates tracked with telemetry. Satellite tracking of long-distance migrants often produces numerous locations of surveyed individuals across their wintering ranges. We examined such wintering tracks to test if the wintering locations obtained from few tracked individuals could be useful to model the full species wintering range, using habitat suitability models. We aimed at predicting the wintering distribution of West European Black Storks Ciconia nigra. We used tracks of 9 storks, retaining one location per winter day per individual for a total of 972 different locations. Combined with bioclimatic and land cover data in habitat suitability modelling within an ensemble forecast framework, we obtained a probabilistic distribution which largely matched the previously reported wintering range of the species in western and central Africa. Using tracks of the six individuals with more than 100 locations each, we obtained a distribution range closely matching the ninebird range. A range similar to the nine-bird range could be predicted by models using data from less numerous individuals and by considering a lower threshold value. Habitat suitability models using wintering record locations of satellite-tracked migrant birds can therefore help to get a better picture of the wintering distribution range, and hence provide more accurate information for conservation planning on African wintering grounds