The health crisis has shed new light on the research and dissemination of scientific culture. Scientists have been thrust into the spotlight, directly engaged by the media and politicians, without clarifying their role in decision-making processes. This frenzy has led to missteps and controversies, sometimes fueled by the scientists themselves, highlighting society's vulnerability to a flood of contradictory information massively spread through social media. These intense debates reveal that society demands to understand the role of science in decisions made by all economic and political actors and that research actors should better explain scientific methods and debates. Therefore, it is now the duty of the scientific community to respond to this call, lest there be a total breakdown of trust. The National Research Agency, through the call for projects "Science with and for Society – Scientific, Technical, and Industrial Culture – AAPG2021," once again provides the opportunity to implement actions for scientific mediation, communication, or valorization around the issues and results of the research projects supported by the Agency in 2021. The CNRS is ideally positioned to respond to this call for projects due to its multidisciplinary coverage, national presence, network of academic partners, and the connections it establishes with actors in scientific, technical, and industrial culture. Its regional presence through delegations such as the Ile-de-France Meudon delegation is an additional asset for developing ambitious local synergies. The National Research Agency's call for projects "Science with and for Society – Scientific, Technical, and Industrial Culture – AAPG2021" is an opportunity for the CNRS to implement a knowledge dissemination project at the district level (including the departments of Hauts-de-Seine, Val d'Oise, Seine-Saint-Denis, and Paris), the SAPS ADRESS 2021-CNRS DR05 project. Through the SAPS ADRESS 2021-CNRS DR05 project, the CNRS aims to showcase the diversity of research conducted in the region to the citizens. By offering various mediation tools, giving a voice to researchers, and leveraging new media to widely disseminate messages, the CNRS aims to promote creativity, culture, and scientific mediation for everyone. By linking territorial actions to national frameworks, it also seeks to significantly contribute to the dialogue between science, research, and society.

Infectious diseases are a major threat for human health and rapidly increasing antibiotics resistance forces us to consider new antimicrobial therapies. The modulation of the innate gut microbiome may represent such a new and promising approach. Though our understanding of the intrinsic interactions between the host, the microbiome and invading pathogens is still limited. One of the key interactions during infection is the nutritional limitation of microelements such as iron. Iron is an essential nutrient for almost all living organisms and is crucial for pathogen survival. During pathogen invasion and gut inflammation, the host limits iron by the production of iron-chelating proteins to hinder pathogen proliferation. This deleterious limitation leads pathogens and members of the microbiome to secrete their own iron-chelating molecules; called siderophores in order to access this essential nutrient. While the host tries to limit its effect on the microbiome, the host maximises its inhibition against pathogens. Now, some pathogens have learned to take advantage of and exploit the microbiome’s siderophores for their own survival. Here I aim to investigate how three enteric pathogens, namely Salmonella, Yersinia and Klebsiella, all leading gut pathogens, exploit the commensal siderophore ferrichrome produced by a L. paracasei strain. I will also explore to which extend this exploitation influence gut invasion and disease outcome. Understanding such complex host-microbiome-pathogen interaction will pave the way to a more complete understanding of the gut physiology during infection and may open some perspectives to a better disease control.

Le projet ProductionSoftwares vise à développer la chaîne de production HD de Mac Guff Ligne (MGL), ainsi que ses outils d’animation, de rendu et de gestion, afin qu’ils permettent la fabrication de longs métrages en 3D, et le renforcement de l’implantation de la société sur les marchés asiatiques et américains. Il est le prolongement de 15 années de développements qui nous ont permis d’acquérir un ensemble de logiciels autonomes, évolutifs et qui répondent exactement aux besoins créatifs de nos métiers et, au-delà, qui ont permis à MGL de devenir un des acteurs importants du cinéma français.

A number of striking similarities have been found in genetic networks that regulate key processes of early embryogenesis as well as organogenesis between insects and vertebrates. To understand these similarities, it has been proposed that broad aspects of body plan organisation were already present in Urbilateria, the last common ancestor of bilaterians, a segmented coelomate animal, looking like an annelid. We are working on this still controversial hypothesis by studying the development of the marine annelid Platynereis dumerilii. We are particularly interested in the genetic mechanisms of metameric segmentation of annelids in order to compare them with analogous networks in insects and vertebrates. We believe this project may provide crucial evidence to understand the early evolution of vertebrates as the « complex Urbilateria » theory stipulates that vertebrates evolved from active annelid-like ancestors. We propose to analyse two fundamental aspects of segment ontogenesis: 1°) How is segment polarity regulated in the annelid ? Expression data suggest the involvement of wnt signalling. We are going to put this idea to the test by interfering with all potential signalling pathways regulated by the Wnt secreted proteins. With the help of small interfering molecules, we are going to test the potential involvement of the Notch pathway in the mesodermal segment polarity to compare with analogous vertebrate processes. In parallel with this candidate gene approach, we are going to develop an unbiased transcriptomic screen to discover the genes regulated by the Wnt/beta-catenin pathway during the establishment of segmental polarity. This approach will be based on quantitative sequencing of multiple cDNA samples of treated larvae as well as posterior segment addition zones of juvenile worms with pro- and anti-beta-catenin drugs. Combined with time series, we hope we will identify the direct transcriptional targets of the beta-catenin pathway. 2°) How does posterior addition work in the annelid ? We are going to characterize the stem cells that are responsible for the addition of new segments during the annelid life. We have shown previously that the ectoderm of new segments at least is produced by the synchronized mitotic activity of a posterior ectodermal ring of stem cells. Using clonal tracing (diI), we are going to determine whether another niche of stem cells is responsible for mesodermal growth as suggested by a set of markers. We are going to characterize systematically the action of hedgehog, Wnt, Notch and FGF pathways on the maintenance and mitotic activity of these stem cell pools. Platynereis, like other annelids, is capable of caudal regeneration. Posterior stem cells therefore can be regenerated from existing segments. We are going to explore with mitotic activity labelling, specific gene markers of stemness and clonal analysis, the origin of the cells that are making the regeneration blastema, We are going in particular to establish whether the blastem is formed by cell dedifferentiation or by pre-existing stocks of segmentel stem cells. We are going to analyse the action of signalling pathways on the formation of the blastema, notably to find out whether they can influence the migratory behaviour of proliferating cells. We hope that we can discover similarities with human adult stem cells and thus put to the test the idea that these human cells are descended from ancestral pluripotent metazoan stem cells.