Cigarette smoke induces apoptosis in the follicle-associated epithelium of murine Peyer's patches

Background: Recently, cigarette smoking has been associated with the development of several auto-immune diseases, including rheumatoid arthritis and inflammatory bowel disease (IBD). The cellular and molecular mechanisms through which cigarette smoking predisposes to IBD are unknown. Cigarette smoke-induced apoptosis is described in several in vivo and in vitro experiments, and might play a role in the pathogenesis of several smoke-associated diseases. The aim of this study was to quantify apoptosis in normal murine Follicle-Associated Epithelium (FAE) and compare this to apoptosis in FAE of smoking mice. Methods: 8 C57BL/6 male mice were exposed to cigarette smoke for 24 weeks (chronic exposure); a control group of 8 mice was exposed to air during the same period. After 24 weeks the mice were sacrificed and Peyer’s patches of each mouse were dissected for histology. Immunohistochemistry for caspase-3 was performed on paraffin-embedded tissue sections of 11 Peyer’s patches of smoking animals and 11 Peyer’s patches of controls. To compare apoptotic activities between smokers and controls, the apoptotic index (percentage of apoptotic cells per 100 cells) in the FAE was calculated. An unpaired student T-test was applied. Results: A statistically significant increase in apoptosis of FAE cells was observed in smoking mice compared to air-exposed mice (P=0.002). In the FAE of smoking animals, the mean apoptotic index was 1.82 with a range of 1.11 to 3.00, whereas the mean apoptotic index in non-smoking animals was 0.92 (range 0.24 -2.06). Most apoptotic cells in both groups were seen at the apex of the FAE. Conclusion: We quantified rates of apoptosis in the FAE of murine Peyer’s patches. Furthermore we compared apoptosis in the FAE of smoking mice versus non-smoking siblings and observed an increased apoptotic index in the FAE of smoking animals. Our results demonstrate that cigarette smoke induces a significant increase of apoptosis in the FAE of murine Peyer’s patches and may point to a role for smoking in the pathogenesis of intestinal inflammation. Further investigation needs to clarify whether this increase in apoptosis influences normal function of the FAE

The development of a novel SNP genotyping assay to differentiate cacao clones

In this study, a double-mismatch allele-specific (DMAS) qPCR SNP genotyping method has been designed, tested and validated specifically for cacao, using 65 well annotated international cacao reference accessions retrieved from the Center for Forestry Research and Technology Transfer (CEFORTT) and the International Cocoa Quarantine Centre (ICQC). In total, 42 DMAS-qPCR SNP genotyping assays have been validated, with a 98.05% overall efficiency in calling the correct genotype. In addition, the test allowed for the identification of 15.38% off-types and two duplicates, highlighting the problem of mislabeling in cacao collections and the need for conclusive genotyping assays. The developed method showed on average a high genetic diversity (He = 0.416) and information index (I = 0.601), making it applicable to assess intra-population variation. Furthermore, only the 13 most informative markers were needed to achieve maximum differentiation. This simple, effective method provides robust and accurate genotypic data which allows for more efficient resource management (e.g. tackling mislabeling, conserving valuable genetic material, parentage analysis, genetic diversity studies), thus contributing to an increased knowledge on the genetic background of cacao worldwide. Notably, the described method can easily be integrated in other laboratories for a wide range of objectives and organisms

A Hormonal Signaling Pathway Influencing C. elegans Metabolism, Reproductive Development, and Life Span

AbstractDuring C. elegans development, animals must choose between reproductive growth or dauer diapause in response to sensory cues. Insulin/IGF-I and TGF-β signaling converge on the orphan nuclear receptor daf-12 to mediate this choice. Here we show that daf-9 acts downstream of these inputs but upstream of daf-12. daf-9 and daf-12 mutants have similar larval defects and modulate insulin/IGF-I and gonadal signals that regulate adult life span. daf-9 encodes a cytochrome P450 related to vertebrate steroidogenic hydroxylases, suggesting that it could metabolize a DAF-12 ligand. Sterols may be the daf-9 substrate and daf-12 ligand because cholesterol deprivation phenocopies mutant defects. Sensory neurons, hypodermis, and somatic gonadal cells expressing daf-9 identify potential endocrine tissues. Evidently, lipophilic hormones influence nematode metabolism, diapause, and life span

Etude de la formation des podosomes endothéliaux en réponse au TGFß (rôle essentiel du récepteur de type I, ALK1, et de la fibronectine dans un contexte d'activation de la cellule endothéliale)

Le TGFB(bêta) est un facteur clé dans l'homéostasie du réseau vasculaire. Le laboratoire a découvert que le TGFB(bêta) induit des podosomes dans les cellules endothéliales (CE) artérielles in vitro. Ces microdomaines riches en F-actine, sont capables de dégrader localement la matrice extracellulaire. Nous avons mis en évidence des structures de même type dans l endothélium natif, démontrant la pertinence des observations in vitro. Les CE expriment 2 récepteurs de type I au TGFB(bêta), ALK5 et ALK1, dont les fonctions respectives sur les CE font l objet de controverses. Nous montrons in vitro, que l assemblage des podosomes est dépendant de ALK1 et est induit dans un contexte d'activation de la CE. La fibronectine, présente dans la matrice lors de situations d'activation de la CE, est régulée par TGFB(bêta) /ALK1 dans notre modèle et est essentielle à la formation des podosomes. L'ensemble des données obtenues laisse présager un rôle des podosomes endothéliaux dans le remodelage artériel en réponse au TGFB(bêta).TGFB(beta), a pleiotrop cytokine, acts as an important regulator for the maintenance of vascular homeostasis. Our team has discovered, for the first time, that TGFB(beta) induces podosomes formation in aortic endothelial cells (EC) in vitro. Podosomes are highly dynamic adhesion microdomains formed at the ventral membrane, consisting of a core of F-actin and actin-associated proteins, surrounded by a ring structure which in turn is consisting of plaque proteins as well as signaling proteins. In addition to the presence of specific markers, they are distinguished from other adhesion structures by the presence of metalloproteases, endowing them with the ability to degrade the extracellular matrix locally. We have bringing to light these structures in the endothelium of native arterial vessel exposed to biologically active TGFB(beta), showing relevance of these structures. Endothelial cells express two types I receptors of TGFB(beta), ALK5 and ALK1, which relative function on EC are controversial. We show in our model in vitro, that podosomes formation is ALK1-dependent and are induced when EC are in an active background. Fibronectin, an extracellular matrix component which is present during active situation, is regulated by TGFB(beta)/ALK1 signaling pathway and is essential for podosomes formation. This work open up new avenues to study the role of podosomes in vascular pathophysiology. We propose that podosomes are involved in arterial vessel remodeling.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

A combined RNA preservation and extraction protocol for gene expression studies in cacao beans

Despite the high economic importance of cacao beans, few RNA-based studies have been conducted on this plant material and hence no optimal RNA-extraction has been reported. Moreover, extraction of high-quality RNA from recalcitrant cacao bean tissue has shown many difficulties and requires optimization. Furthermore, cacao beans are mostly found at remote and under-resourced locations, which pressures the outsourcing of such analysis and thereby demands RNA-stable preservation and transportation of cacao beans. This study aims to select an appropriate RNA extraction and preservation/transportation method for cacao beans. For this purpose, three sample homogenization and five extraction protocols on cacao beans were compared. In addition, 13 preservation conditions-differing in tissue crushing degree, preservation method, duration, and temperature-were compared and evaluated. A comparative analysis revealed that CTAB-based homogenization and extraction outcompeted all tested commercial protocols in RNA yield and integrity, respectively. Preservation at -80 degrees C affected RNA quality the least, whereas freeze-drying was most suitable for transportation at room temperature for maximum 1 week. The cacao bean RNA obtained from the selected methods were compatible for downstream applications. The results of this study will facilitate on-field sampling and transportation of genetically sensitive cacao material prior to cacao bean transcriptomic studies. In addition, valuable insights on sample homogenization, extraction, preservation, and transportation have been provided, which is of interest to every plant geneticist

Multi-physical modelling and analysis of lubricated transmissions using a coupled finite element approach

Lubrication is vital to improve performance, efficiency and durability in transmissions; it serves to minimize wear, noise, vibration and friction. The proper functioning of lubricated transmissions relies on interactions amongst a wide range of physical phenomena (contact dynamics, fluid-structure interaction and heat transfer) operating at different spatial and temporal scales. A lubricated transmission model is proposed in this work to obtain accurate information regarding all physical domains and the coupling thereof to quantify performance, efficiency and durability. The model consists of a thermo-elastically coupled flexible multibody model for the gear pair and a Thermo-Elasto-Hydrodynamic Lubrication (TEHL) model for the lubricant, both based on first principle modelling to ensure high fidelity