For roughly thirty years, there is extensive evidence that neither total nor dissolved aqueous metal concentrations are good predictors of metal bioavailability and toxicity. On another side, speciation information has been found fundamental to understand interaction between inorganic contaminants and biomolecules during the transport, incorporation and fixation into a biological cell or tissue. Thus the characterization of biomolecules involved in metabolic pathways and interacting with an element is a key point to elucidate the toxicity of an element. However, the most challenging task is to preserve the integrity of metal-biomolecule complexes from the separation/purification procedure until their identification. This difficulty of the characterization of metal coordination complexes with biomolecules spurs development of new analytical methodologies. The project proposes to develop analytical methodologies allowing the characterization of intact uranium-biomolecules complexes within biological environmental matrices coming from aquatic organisms. This, after exposure of these organisms, dissection of organs of interest and uranium microdistribution analysis in the different fractions of work. New methodologies will allow : (i) A first screening of uranium-protein complexes thanks to the development of uranium imaging in proteins spots of non denaturating 2D-PAGE by Laser Ablation coupled to ICP MS; this will be achieved if an optimized non denaturating separation protocol by 2D gel electrophoresis is developed. Quantitative information will be addressed using unspecific isotopic dilution analysis. (ii) Secondly, the characterization of intact uranium-protein complexes. Using the complementarity of ICP MS and molecular mass spectrometry, a top-down strategy will be developed and include a non denaturating separation of intact uranium-protein complexes by means of preparative gel electrophoresis or multidimensional liquid chromatography (depending on the molecular weight of the uranium-binding proteins) and the identification of the uranium-complexes fragments by high resolution mass spectrometry (FT MS orbitrap). (iii) Thirdly, the characterisation of uranium-metabolites complexes. The developed analytical methodology will combine orthogonal and non denaturating chromatographic mechanisms for the separation of intact uranium-metabolites complexes and high resolution mass spectrometry for their identification. These developments in addition with the realization of a typical uranium metallomics study should allow the investigation of uranium speciation in aquatic organisms such as bivalves (Corbicula fluminea), crayfish (Orconectes limousus) or fish (Danio rerio) which are often used as inorganic pollutants bioindicators. This in vivo characterization of uranium target biomolecules (proteins or metabolites) will be carried out at the basal level and after different condition of exposure of the aquatic organisms (environmental versus incidental). These results will provide insights into the mechanisms by which uranium is sensed, stored, incorporated or released from the aquatic organism organs. In addition, as some toxicity parameters has been previously determined in the conditions of exposure chosen, correlations between uranium speciation and the toxic fraction towards the organisms under study will be investigated. Such work could finally offer interesting prospects for risk assessment linked to uranium exposure (implementation of existing models).

Mandibular osteoradionecrosis (ORN), characterized by extensive and irreversible bone necrosis secondary to ionizing radiation, is a serious complication of radiotherapy treatment. For these patients, therapeutic options are limited due to a severe bone ischemia associated with a cancerous context. Consequently, the development of innovative biotherapies targeting both osteogenesis and angiogenesis is essential to enable satisfactory bone repair. Bone Morphogenetic Proteins 2/4/7 (BMPs), known for their angio- and osteo-genetic properties, have been widely studied for bone regenerative medicine strategies. However, these are characterized by high cost and require supra-physiological doses, this combined with their pro-proliferative activity makes them impossible to use in a tumoral context. Matrix GLA protein (MGP), an inhibitor of BMPs in a proline64 (Pro64) dependent manner, also possesses GLA domains responsible for anti-calcification activity. Our data have shown that mice model carrying a p.P64G mutation (MgpKiPro64) exhibits increased vasculogenesis and osteogenesis, without ectopic vascular calcification. These findings suggest that modulation of the BMPs/MGP interaction could promote bone and vascular growth without the adverse effects associated with the use of exogenous BMPs. Hence, the objectives of this project are to: 1) screen peptide inhibitors that can block the interaction between MGP and BMPs; 2) functionalize an injectable bone substitute; and 3) assess its efficiency in treating ORN in rodents. Therefore, identifying the interaction zone between BMPs and MGPs accurately by utilizing a peptide-based inhibitor while preserving the GLA domains could provide an encouraging approach to improving the bioavailability and consequently the bioactivity of endogenous BMPs for patients struggling with ORN.

Les objectifs généraux de ce programme sont de suivre les niveaux de la contamination dans le merlu (Merluccius merluccius) du golfe du Lion en Méditerranée Nord Occidentale et dans les espèces principales de son réseau trophique pour identifier les processus clés qui agissent sur le devenir des contaminants, à fin d’établir une formulation mathématique de ces processus de manière à les inclure dans un modèle calibré et validé par les mesures in situ et si possible à partir de bassins expérimentaux. L’objectif final est d’obtenir un modèle prédictif de l’exposition d’une espèce représentative du golfe du Lion aux contaminants chimiques qui pourra servir d’outil de base pour l’évaluation des effets des contaminants sur les ressources aquatiques. Le Rhône joue un rôle majeur dans les apports de différents types de contaminants (polluants organiques, métaux lourds, et radionucléides) qui proviennent des activités anthropiques. Ils sont véhiculés notamment par le biais de la matière organique particulaire (MOP) qui sédimente en majeure partie sur le plateau continental et va influencer fortement la composition et l’abondance des communautés macrobenthiques situées à la base des réseaux trophiques marins. La structure du réseau trophique du merlu, permet d’identifier les espèces principales chez lesquelles seront établis les niveaux de contamination.

During a severe accident in a Light Water Reactor, large amounts of hydrogen gas are likely to be generated and released into the containment during core degradation, potentially raising a combustion hazard. Additional burnable gases (H2 and CO) may be released into the containment volume in case of Molten Corium/Concrete Interaction leading, in case of ignition, to pressure and temperature loads that may challenge the containment and safety components integrity. Mitigation measures are often employed to avoid severe damage when the atmosphere of NPP containment is combustible during an accident. NPP personnel as well as safety authorities need information on the status of the gas mixture inside the containment to select suitable and timely measures. Therefore, gas concentration monitoring systems are important in supporting personnel to make appropriate decisions. Usually, H2 monitoring systems are based on few (less than 10) sensors located in different area of the containment. Based on these gas concentration measurements, operators may take decisions as postponing the spray activation, venting line opening … Existing measurement techniques have limitations and drawbacks: they do not work under the conditions of the late phases of a severe accident, when oxygen is lacking and carbon monoxide is present in the atmosphere of the containment, or because they increase the risk of leakage from the containment. To overcome these limitations and as part of the French MITHYGENE project, the COMOS prototype was developed, based on Raman optical technology, and qualified under severe accident conditions. This monitoring technique offers several decisive advantages, such as local, distributed and chemically selective gas measurement. It aims to provide in situ accurate information on the gas mixture (H2, O2, N2, H2O, CO, CO2) in near-real time at several locations inside the containment. The prototype has a TRL of 5 to 6 and has given rise to three patent applications.