ARSA : Analyse de Réseaux Sociaux pour les Administrations

International audienceIn this paper we give a first summary of the ARSA project which tends to promote the using of social networks in public administrations, with experimentation in collaboration with the town of Antibes. The integration of social networks in administrations is tested in two directions: on the one hand we address the design and the installation of an internal social network that takes into account the hierarchical organization of the administration, but allows other types of relationships; on the other hand we setup a monitoring tool of the e-reputation of the town of Antibes on the external network Twitter. The two axes of this integration are discussed in detail in this paper

Resistance to CLnA-induced ferroptosis is acquired in Caco-2 cells upon differentiation

In contrast to canonical ferroptosis inducers, highly peroxidable conjugated linolenic acids (CLnA) directly fuel the lipid peroxidation cascade upon their incorporation into membrane phospholipids. Little is known, however, about the cytotoxicity level of CLnAs to normal epithelial cells. Caco-2 cells, derived from colorectal adenocarcinoma, spontaneously differentiate into enterocyte-like cells over a period of 21 days of cell culturing, allowing for graduated phenotypic shift from proliferative, undifferentiated cells to a functional intestinal barrier. We exploited this property to assess the sensitivity of Caco-2 cells to CLnAs at different stages of differentiation. Our results show a significant decrease in CLnA-induced ferroptotic cell death over time. The acquired resistance aligned with decreases in cell proliferation and in the extent of lipid peroxidation, as well as with an increase in the expression of GPX4 upon differentiation. These results highlight that while CLnAs are highly toxic for proliferating cancer cells, differentiated epithelial cells are resistant to CLnA-induced ferroptosis. Therefore, this study gives credential to the therapeutic use of CLnAs as an anticancer strategy and offers a new model study to further investigate the safety of peroxidable fatty acids in differentiated cells

Sequevar Diversity and Virulence of Ralstonia solanacearum Phylotype I on Mayotte Island (Indian Ocean)

The genetic and phenotypic diversity of the Ralstonia solanacearum species complex, which causes bacterial wilt to Solanacae, was assessed in 140 strains sampled from the main vegetable production areas of the Mayotte island. Only phylotype I strains were identified in the five surveyed areas. The strains were distributed into the following 4 sequevars: I-31 (85.7%), I-18 (5.0%), I-15 (5.7%), and I-46 (3.6%). The central area of Mayotte was the most diverse region, harboring 4 sequevars representing 47.1% of the collected strains. Virulence tests were performed under field and controlled conditions on a set of 10 tomato breeding line accessions and two commercial hybrid tomato cultivars. The strains belonging to sequevar I-31 showed the highest virulence on the tomatoes (pathotypes T-2 and T-3), whereas sequevars I-18, I-15, and I-46 were grouped into the weakly T-1 pathotype. When the tomato accessions were challenged in the field and growth chambers, the highest level of resistance were observed from the genetically related accessions Hawaii 7996, R3034, TML46, and CLN1463. These accessions were considered moderately to highly resistant to representative strains of the most virulent and prevalent sequevar (I-31). Interestingly, the Platinum F1 cultivar, which was recently commercialized in Mayotte for bacterial wilt resistance, was highly or moderately resistant to all strains. This study represents the first step in the rationalization of resistance deployment strategies against bacterial wilt-causing strains in Mayotte

Punicic Acid Triggers Ferroptotic Cell Death in Carcinoma Cells

Plant-derived conjugated linolenic acids (CLnA) have been widely studied for their preventive and therapeutic properties against diverse diseases such as cancer. In particular, punicic acid (PunA), a conjugated linolenic acid isomer (C18:3 c9t11c13) present at up to 83% in pomegranate seed oil, has been shown to exert anti-cancer effects, although the mechanism behind its cytotoxicity remains unclear. Ferroptosis, a cell death triggered by an overwhelming accumulation of lipid peroxides, has recently arisen as a potential mechanism underlying CLnA cytotoxicity. In the present study, we show that PunA is highly cytotoxic to HCT-116 colorectal and FaDu hypopharyngeal carcinoma cells grown either in monolayers or as three-dimensional spheroids. Moreover, our data indicate that PunA triggers ferroptosis in carcinoma cells. It induces significant lipid peroxidation and its effects are prevented by the addition of ferroptosis inhibitors. A combination with docosahexaenoic acid (DHA), a known polyunsaturated fatty acid with anticancer properties, synergistically increases PunA cytotoxicity. Our findings highlight the potential of using PunA as a ferroptosis-sensitizing phytochemical for the prevention and treatment of cancer

Regulatory and Pathogenic Mechanisms in Human Autoimmune Myasthenia Gravis

International audienceThe thymus is frequently hyperplastic in young female myasthenia gravis (MG) patients presenting with anti-acetylcholine receptor (AChR) antibodies. This thymic pathology is characterized by the presence of ectopic germinal centers (GCs) containing B cells involved at least partially in the production of pathogenic anti-AChR antibodies. Our recent studies have furthered our understanding of the mechanisms leading to GC formation in the hyperplastic thymus. First, we showed that CXCL13 and CCL21, chemokines involved in GC formation, are overexpressed in MG thymus. Second, we demonstrated an increase in pro-inflammatory activity in the thymus from MG patients and its partial normalization by glucocorticoids, as evidenced by gene expression profile. Third, we found that pro-inflammatory cytokines are able to upregulate the expression of AChR subunits in thymic epithelial and myoid cells. Fourth, we showed that the function of T regulatory (Treg) cells, whose role is to downregulate the immune response, is severely impaired in the thymus of MG patients; such a defect could explain the chronic immune activation observed consistently in MG thymic hyperplasia. Altogether, these new data suggest that CXCL13 and CCL21, which are produced in excess in MG thymus, attract peripheral B cells and activated T cells, which are maintained chronically activated in the inflammatory thymic environment because of the defect in suppressive activity of Treg cells. Presence of AChR in the thymus and upregulation of its expression by the pro-inflammatory environment contribute to the triggering and maintenance of the anti-AChR autoimmune response

La part esthétique de l'architecture

« Les goûts et les couleurs, ça ne se discute pas ! » Voilà une idée que cet ouvrage vient bousculer. La part esthétique de l’architecture présente une histoire de l’évolution de la pensée esthétique en Occident, de l’Antiquité à nos jours. Son corpus de références croise l’architecture avec la philosophie, l’esthétique, l’histoire et l’histoire des arts plastiques. Des liens avec l’architecture d’aujourd’hui viennent clore chaque chapitre, ouvrant aux lecteurs et lectrices la voie de leurs propres réflexions à l’égard du beau et de l’architecture. Un ouvrage concis, richement illustré, accessible à toute personne désireuse d’affiner son appréciation de l’art en général et de l’architecture, en particulier. Le livre a été pensé et rédigé pendant le confinement strict du printemps 2020 par des étudiantes et étudiants de la deuxième année de bachelier, organisée pour la formation des ingénieurs architectes à l’UCLouvain

Circulating tumour cells as a potential biomarker for lung cancer screening: a prospective cohort study

International audienceBackground Lung cancer screening with low-dose chest CT (LDCT) reduces the mortality of eligible individuals. Bloodsignatures might act as a standalone screening tool, refine the selection of patients at risk, or help to classifyundetermined nodules detected on LDCT. We previously showed that circulating tumour cells (CTCs) could bedetected, using the isolation by size of epithelial tumour cell technique (ISET), long before the cancer was diagnosedradiologically. We aimed to test whether CTCs could be used as a biomarker for lung cancer screening.Methods We did a prospective, multicentre, cohort study in 21 French university centres. Participants had to beeligible for lung cancer screening as per National Lung Screening Trial criteria and have chronic obstructivepulmonary disease with a fixed airflow limitation defined as post-bronchodilator FEV1/FVC ratio of less than 0∙7.Any cancer, other than basocellular skin carcinomas, detected within the previous 5 years was the main exclusioncriterion. Participants had three screening rounds at 1-year intervals (T0 [baseline], T1, and T2), which involved LDCT,clinical examination, and a blood test for CTCs detection. Participants and investigators were masked to the results ofCTC detection, and cytopathologists were masked to clinical and radiological findings. Our primary objective was totest the diagnostic performance of CTC detection using the ISET technique in lung cancer screening, compared withcancers diagnosed by final pathology, or follow up if pathology was unavailable as the gold standard. This studyis registered with ClinicalTrials.gov identifier, number NCT02500693.Findings Between Oct 30, 2015, and Feb 2, 2017, we enrolled 614 participants, predominantly men (437 [71%]), aged65∙1 years (SD 6∙5), and heavy smokers (52∙7 pack-years [SD 21∙5]). 81 (13%) participants dropped out betweenbaseline and T1, and 56 (11%) did between T1 and T2. Nodules were detected on 178 (29%) of 614 baseline LDCTs.19 participants (3%) were diagnosed with a prevalent lung cancer at T0 and 19 were diagnosed with incident lungcancer (15 (3%) of 533 at T1 and four (1%) of 477 at T2). Extrapulmonary cancers were diagnosed in 27 (4%) ofparticipants. Overall 28 (2%) of 1187 blood samples were not analysable. At baseline, the sensitivity of CTC detectionfor lung cancer detection was 26∙3% (95% CI 11∙8–48∙8). ISET was unable to predict lung cancer or extrapulmonarycancer development