Étude des interactions cellule-matrice dans l'ancrage des cellules souches intestinales humaines

Dans cette étude, les intégrines al*1 et a2*1 ainsi que le dystroglycan ont été analysés dans la muqueuse intestinale humaine et les modèles cellulaires épithéliaux. Les résultats obtenus par immunofluorescence indirecte, immunobuvardage de type western et RT-PCR, ont permis de démontrer leur présence dans le compartiment épithélial prolifératif au cours du développement foetal. Chez l'adulte, la sous-unité a1 des intégrines et le dystroglycan ont été retrouvés en co-distribution avec la laminine-2. In vitro, les trois récepteurs étaient exprimés par les cellules intestinales humaines indifférenciées HIEC-6. Dans un second temps, ces cellules ont été utilisées afin d'évaluer l'impact des régulateurs du développement intestinal (EGF et glucocorticoïdes), sur la mise en place d'un système d'ancrage intégrine dépendant. Les analyses ont révélé une modulation différentielle de l'expression des sous-unités a1 et a2. De même, le potentiel adhésif des cellules HIEC-6 a également été altéré par ces facteurs de croissance."--résumé abrégé par UMI

Bioavailability and Effects of Polystyrene Nanoparticles in <em>Hydra circumcincta</em>

The release of nanoplastics (NPs) from the weathering and degradation of plastics in the environment is an important concern to aquatic ecosystems. The purpose of this study was to examine the bioavailability and toxicity of 50 and 100 nm fluorescently labeled polystyrene nanoplastics (NP) to the invertebrate Hydra attenuata. The hydrae were exposed to increasing concentrations of 50 and 100 nm NPs (1.25-80 mg/L) for 96 h at 20°C. A subgroup of hydra was depurated in media to determine the persistence of effects. The results revealed that the animals accumulated detectable amounts fluorescent NP and produced morphological changes at a threshold concentration between 5 and 10 mg/L. The hydrae were able to eliminate 76 and 78% of the 50 and 100 nm NPs, respectively. A characteristic tentacle detachment from the body was observed. Biochemical markers were also determined in exposed organisms and increased glutathione S-transferase (GST) activity, oxidative damage and neutral lipids levels that persisted after the 24 h. In conclusion, NPs are bioavailable to Hydra, produce morphological changes and increase oxidative stress and neutral lipids. The formation of neutral lipids could be the result of reduced food assimilation or a means for the elimination of NPs

Étude des interactions cellule-matrice dans l'ancrage des cellules souches intestinales humaines

Dans cette étude, les intégrines al*1 et a2*1 ainsi que le dystroglycan ont été analysés dans la muqueuse intestinale humaine et les modèles cellulaires épithéliaux. Les résultats obtenus par immunofluorescence indirecte, immunobuvardage de type western et RT-PCR, ont permis de démontrer leur présence dans le compartiment épithélial prolifératif au cours du développement foetal. Chez l'adulte, la sous-unité a1 des intégrines et le dystroglycan ont été retrouvés en co-distribution avec la laminine-2. In vitro, les trois récepteurs étaient exprimés par les cellules intestinales humaines indifférenciées HIEC-6. Dans un second temps, ces cellules ont été utilisées afin d'évaluer l'impact des régulateurs du développement intestinal (EGF et glucocorticoïdes), sur la mise en place d'un système d'ancrage intégrine dépendant. Les analyses ont révélé une modulation différentielle de l'expression des sous-unités a1 et a2. De même, le potentiel adhésif des cellules HIEC-6 a également été altéré par ces facteurs de croissance."--résumé abrégé par UMI

Form-Dependent Toxicity of Silver Nanomaterials in Rainbow Trout Gills

The toxicity of the form of nanoparticles is presently not well understood. The purpose of this study consists in comparing the toxicity of various forms of silver nanoparticles (nAg) in juvenile rainbow trout Oncorhynchus mykiss. Juveniles were exposed to various forms of polyvinyl-coated nAg of similar size for 96 h at 15 °C. After the exposure period, the gills were isolated and analyzed for Ag uptake/distribution, oxidative stress, glucose metabolism, and genotoxicity. Higher levels of Ag were detected in gills in fish exposed to dissolved Ag followed by spherical, cubic, and prismatic nAg. Size-exclusion chromatography of gill fractions revealed that the dissolution of nAg was observed for all forms of nAg where prismatic nAg released more important levels of Ag in the protein pool as in fish exposed to dissolved Ag as well. The aggregation of nAg was more important for cubic nAg in respect of the other forms of nAg. The data revealed that lipid peroxidation was closely associated with protein aggregation and viscosity. Biomarkers revealed changes in lipid/oxidative stress and genotoxicity, which were related to the loss of protein aggregation and inflammation (NO2 levels), respectively. In general, the observed effects were found for all forms of nAg where the effects from prismatic nAg were generally higher than for spherical and cubic nAg. The strong relationship between genotoxicity and inflammation response suggests the participation of the immune system in the observed responses of juvenile fish gills

Innovative Methodology Normalizing genes for quantitative RT-PCR in differentiating human intestinal epithelial cells and adenocarcinomas of the colon

quantitative RT-PCR in differentiating human intestinal epithelial cells and adenocarcinomas of the colon. Am J Physiol Gastrointest Liver Physiol 290: G1067–G1074, 2006. First published January 6, 2006; doi:10.1152/ajpgi.00234.2005.—As for other mRNA measurement methods, quantitative RT-PCR results need to be normalized relative to stably expressed genes. Widely used normalizing genes include �-actin and glyceraldehyde-3-phosphate dehydrogenase. It has, however, become clear that these and other normalizing genes can display modulated patterns of expression across tissue types and during complex cellular processes such as cell differentiation and cancer progression. Our objective was to set the basis for identifying normalizing genes that displayed stable expression during enterocytic differentiation and between healthy tissue and adenocarcinomas of the human colon. We thus identified novel potential normalizing genes using previously generated cDNA microarray data and examined th

Potential markers of oocyte developmental competence in cumulus cells: comparative analysis of in vitro and in vivo maturation in bovine (Bos taurus)

Poster 23absen

Cumulus cells transcriptomics revealed the potential biomarkers of oocyte development competence and differences in signaling pathways during in vitro and in vivo maturation bovine

absen

Saccharomyces cerevisiae modulates gut responses to Escherichia coli in pigs

International audienc