According to the nutritional and health recommendations of the French National Program for Nutrition and Health (Programme National Nutrition Santé, PNNS), the development of food products combining nutritional and organoleptic qualities for the benefit of the consumers' health and well-being is of paramount importance. The reduction of salt, sugar and fat represents one of the means for the development of food with good nutritional quality. This reduction can however be associated with a loss of organoleptic quality of reformulated food. Meanwhile, hedonic properties of food represent a key factor for its palatability. Since consumers’ preferences lean towards a high liking for sweet and fat food, new means to avoid rejection of healthier food are required. Food can be regarded as a complex multimodal perceptual stimuli, involving several dimensions. The holistic perception of taste, odor and aroma constitutes the flavor, which gives its identity and typicality to a food product. It is difficult to distinguish between the taste and the aroma: what is often believed to be the "taste" of food is in reality its odor. Interestingly, due to the association of aroma and taste into a single object named flavor, when a taste–odor association exists, the odor alone may be sufficient to produce the flavor perception. For example, the taste of a sucrose solution is perceived sweeter after addition of a caramel aroma. Likewise, an odor associated to a salty taste can enhance the salty perception. In this way, flavorings can be used to counterbalance salt, sugar or fat reduction in foods. Aromas are often perceived in mixtures, which can lead to a homogeneous percept when a single odor is perceived from the mixture. The homogeneous percept is the subject of important applications in food flavoring, either to give or restore flavor typicality through the use of blending aroma mixtures, or to mask off-flavors. Nevertheless, the processes involved in the homogeneous perception of odor mixtures are still poorly understood. In this context, a fundamental study of homogeneous percept can bring essential knowledge to manage the aroma formulation, which, in turn, will result in food that meets both consumer expectations and criteria of healthy food. The objective of the MULTIMIX project is to identify the biological and molecular characteristics of odorants that induce a homogeneous percept. In this perspective, MULTIMIX proposes a strong combination of in silico, in vitro, ex-vivo and in vivo approaches. Together, these approaches will be used to improve the understanding of homogeneous perception of odor mixtures and to provide, in fine, an assemblage of models for decision-support in formulation of aroma blending. Peripheral mechanisms occurring in the nose have been proposed to play a decisive role in the processing of mixture information. The understanding of mechanisms involved in the perception of odor mixtures at the peripheral level of olfactory process is a challenging subject. In the MULTIMIX project, we will capitalize on previous studies done by several partners of the MULTIMIX consortium to explore the properties of several mixtures of odorants eliciting blending and masking. For instance, we will investigate the mixture of two odorants having strawberry and caramel odors respectively, which gives rise to the configural odor of pineapple. MULTIMIX is an ambitious project that will have a significant impact in several domains of food chemistry and olfactory perception (food science, psychophysics, computational chemistry, neurophysiology, cognitive neurosciences).

[Non-confidential summary] This project addresses the call of the Action Plan 2016 of ANR for Nanomaterials and nanotechnologies for tomorrow products - Innovative nano-objects for health. The main objective is the development of a supramolecular platform for biomedical applications such as multimodal imaging, early stage diagnosis and ultimately medical treatment of arthritis. Our method holds promises for future extensions to other diseases, because of its innovative modular approach. Building on a polyrotaxane platform that was adapted from literature by the principal investigator during preliminary work, we plan to synthesize versatile building block molecules that self-assemble to yield large supramolecular architectures. These building block molecules are functionalized individually with markers for imaging, or vectors for targeting. The self-assembly procedure thus yields multifunctional agents which fulfill the features for modern cutting edge vectors for diagnosis and monitored therapy. The key advantages of our strategy consist in i) its exceptional modularity as different combinations can be obtained easily from the same set of building blocks; and ii) its high flexibility because the functions and their synthesis can be optimized individually and separately on each building block. Thus, our project goes beyond existing systems as it combines molecularly defined synthesis with the biomedical advantages of macromolecular assemblies. We will focus on biocompatible and biodegradable molecules, in contrast to nanoparticles, to obtain a powerful nanometric imaging agent. The chemistry part of the project consists of organic synthesis, coordination chemistry and characterization of molecular and supramolecular compounds. The project is target oriented towards arthritis, with the ultimate goal for early stage diagnosis and monitoring disease progression. Within this project, we plan to optimize key functions and properties, and to improve the pharmacokinetics and pharmacodynamics of our supramolecular compounds. Therefore we will assess physicochemical behavior in solutions and biological media (charge, size, stability). We will check on a routine base the toxicity of all new compounds by MTT conversion assay, before studying the biodistribution in animal models. We will develop multimodal imaging by combining at least two different markers, in particular fluorescence labels and MRI contrast agents to benefit from their complementary sensitivity and resolution to ensure quantitative diagnosis. Their potential for combined imaging experiments will be evaluated in optical imaging platforms (quantum yield, stability) equipped with the latest technologies (3D) and in micro MR imaging systems at high magnetic field (relaxivity). After optimization of all biodistribution and sensitivity features of our platform in healthy animals, we will use it for the study of inflammatory arthritis in a transgenic mouse model in a non-targeted and TNF-a targeted form. Thus, an interdisciplinary consortium of chemists, biophysicists, pharmacologists and physicians has joined together to generate novel probes for clinical applications that require the detection of specific biochemical signatures. The proposal is upstream of clinical research. It consists mainly in the development of a conceptually new, supramolecular theranostic agent. It requires new chemical synthesis for compounds with specific properties, and their characterization in biological and biophysical tests for diagnosis. For this, we request funding for a PhD student, a post-doctoral associate and laboratory expenses.

Environmental pollution represents a growing threat for industrial and third world countries. It can lead to a disruption of ecosystem balance and has been partly associated with several major human diseases including asthma, diabetes or cancer. Environmental pollutants include numerous chemical families (arylamides, aromatic hydrocarbons, dioxins…). organisms have developed a few pleiotropic “sensors” (xenobiotic receptors), which detect and activate enzymatic and transport machineries allowing the elimination of xenobiotics (Tompkins and Wallace, 2007). One of the most important xenobiotic “sensor” is the Aryl hydrocarbon Receptor (AhR) (Barouki et al., 2007); dioxins, polycyclic aromatic hydrocarbons (PAH) and other environmental pollutants bind and trigger this ligand-activated transcription factor which increases the expression of several xenobiotic metabolism enzymes (XME). The role of the AhR in this adaptative response (typically, one xenobiotic activates its own metabolism) is well characterized in mammals (Wilson and Safe, 1998). However, recent studies suggest that this transcription factor regulates alternative signaling pathways independently of exposure to pollutants; invertebrates express AhR orthologs which do not bind xenobiotics (AhR-1 in Caenorhabditis elegans and Spineless in Drosophila melanogaster) in a specific group of neurons (Crews and Brenman, 2006; Huang et al., 2004; Powell-Coffman et al., 1998; Qin and Powell-Coffman, 2004; Qin et al., 2006). Analysis of ahr-1 mutants shows that, in C. elegans, the receptor promotes social feeding (Qin et al., 2006). The observed defects suggest that, in nematodes, AhR-1 is a central regulator of the neural circuit involved in aggregation behavior. While mammalian studies of AhR have mainly focused on its role as a regulator of XMEs, they have largely underestimated its potential endogenous functions, especially in the central and peripheral nervous system. The expression and function of the mammalian protein AhR in the nervous system is largely unknown. Moreover, several AhR ligands are suspected to be neurotoxic but the associated cellular mechanisms are not fully characterized (Gassmann et al., 2010; Kim and Yang, 2005; Latchney et al., 2010; Williamson et al., 2005). We speculate that the protein could also be critical for neural mammalian development. The present project aims 1) to characterize the expression of the AhR (mRNA and protein) in both central and peripheral nervous system and identify its endogenous neural functions using rodent models (wild-type vs knock-out mice) setting up behavioral and neurobehavioral tests, 2) to study the implication of the AhR in the myelination process in the mammalian nervous system, 3) to characterize the consequences of exposure to different AhR ligands on these behaviors. Parts 1-2 and 3 are related because disruption of endogenous functions may constitute one of the toxicity mechanisms of AhR ligand xenobiotics. This ANR program integrates both basic and applied research and is focused on the effects of neurotoxic pollutants in mammalian models. It constitutes a functional mechanistic approach that extends our recent work describing the identification of AhR targets in the mammalian central nervous system (preliminary data).

Inborn enzyme defects of fatty acid ß-oxidation (FAO) form a group of genetic disorders associated to life-threatening pediatric presentations, or to milder phenotypes with later onset and severity. Advances in diagnosis revealed a large number of disease-causing genes , and a continuous increase in the number of patients. However, little progress was made in their treatment. In recent years, our group demonstrated that a target-based pharmacological strategy could result in up-regulation of deficient enzyme activity, and could be successful for correction of some FAO disorders. In line with this, the aim of this project is, based on their presumed mechanism of action, to screen new candidate molecules for the therapy of inborn FAO disorders. AMPK (AMP activated protein kinase) is considered to be a key energy sensor of the cells activated by all metabolic stress conditions that generate an increase in the AMP/ATP ratio. Given the central role of AMPK in energy metabolism, it was identified as a valuable therapeutic target for the treatment of several diseases like type II diabetes or obesity. In recent years, academic laboratories and pharmaceutical companies have studied the effects of many direct or indirect activators of AMPK in the field of common diseases. We hypothesize that the AMPK signaling pathway could be a highly relevant system in our research of new therapeutic targets for the treatment of FAO disorders. In line with this, our project aims at investigating if AMPK activators could represent candidate molecules for correction of FAO disorders in a large panel of deficient patients’ fibroblasts. Cells: Control or patient fibroblasts. This project will benefit of the large cells repository and the expertise on FAO-deficiency of the service of Biochemistry (Bicêtre Hospital): we will test around 100 FAO-deficient fibroblasts. Compounds: We will study the effects of drugs, and of experimental (collaboration with GlaxoSmithKline) or natural compounds, considered as direct or indirect activators of AMPK. Methods: To address theses issues we will use various pharmacological approaches previously developed in our group. The initial readout for the effects of tested compounds will be the measurement of tritiated palmitate oxidation capacities, according to a standardized assay routinely used in our group. We will also analyze by western-blot the possible changes in FAO protein levels to determine if pharmacological improvements are due to increases in mutated protein level, as anticipated. Finally, quantification of mRNA levels of FAO genes will be performed to determine if the various compounds do act at the level of gene expression. Molecular mechanisms: For compounds inducing a correction of FAO flux in cells, we will analyze the involvement of AMPK/PGC-1a axis by siRNA strategy. Indeed, the effects of AMPK activators on mitochondrial metabolism are supposed to be mediated by the activation of PGC-1a (a transcriptional co-activator) through its phosphorylation. Phosphorylation of AMPK and of its downstream target Acetyl-CoA carboxylase, and phosphorylation of PGC-1a will be studied. Mitochondrial biogenesis: As just mentioned, activation of PGC-1a is part of the molecular mechanisms suggested to explain the effect of AMPK activators on mitochondrial energy metabolism. Since PGC-1a is a key regulator of mitochondrial biogenesis, we will determine if active compounds for the correction of FAO also induce a mitochondrial biogenesis, by the study of three different parameters. Altogether, this project should allow identifying possible new candidate drug(s) for the treatment of mitochondrial FAO diseases, and provides a true pre-clinical evaluation of the tested compounds that could benefit shortly to patients.

Human and wildlife animals are exposed to multiple sources of environmental stressors including chemicals such as persistent organic pollutants (POPs) and endocrine disrupting compounds (EDCs). In addition to the important public health issues related to such exposures, EDCs are suspected to elicit ecosystems toxicity with an impact on the food chain and biodiversity and a significant economic burden linked to the increase of metabolic and neurodevelopmental disorders. In this complex and multifactorial context, new and innovative approaches are warranted to address potential linkages between such environmental exposure and health outcomes. Whereas exposure models in toxicology and ecotoxicology traditionally link a given external exposure source with a target organism, the vision of CREATIvE is to consider the organism as both an internal exposure source and a target. Specifically, its ambition is to assess potential health consequences from the release of POP mixtures from an internal storage site (the source) by understanding their complex biological modes of action (MoAs) on the target tissues of the same organism. It is well known that POPs bio-accumulate in living organisms and are stored in specific tissues e.g. adipose tissue (AT) brain, and liver, for long periods of time. Therefore, these tissues represent internal chronic sources of pollutants possibly leading to various disorders including metabolic and neurodegenerative diseases. Such “internal” exposures are not satisfactorily captured by current methods based on investigating different types of external POPs exposure via gavage, injection or acute inhalation. The proposed protocol will not replace the existing ones but will be complementary, taking into account for the first time internal sources of exposure. The aim of CREATIvE is to develop a novel strategy exploring the effects of an internal exposure from grafted contaminated AT. The kinetics and consequences from a redistribution of POPs and their metabolites from grafted contaminated AT on several tissues and organs, e.g. liver, brain and host AT will be studied. The proposed integrated approach is a combination of experimental studies (chemical quantitative measurements in tissues, metabolomics, transcriptomics) and computational modeling (PBPK and systems biology approaches). The advantage of developing such integrated approaches is the possibility to identify the systemic effects of internal mixture exposure at different biological levels, by mimicking the reality of human and animal exposure. As results, new biomarkers will be characterized, and novel complementary models will be proposed which will help at increasing Agregated Exposure Pathways (AEPs) information. To our knowledge such a strategy is clearly innovative and different from existing studies. In a recent preliminary study, an allograft model was developed at Paris Descartes, consisting in a mouse graft of contaminated AT to a non-contaminated mouse. We demonstrated that four weeks after transplantation, the grafts are vascularized and functional. In those initial studies, donor AT was contaminated by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and we showed that this contaminant was indeed redistributed to different tissues with different kinetics. Based on this acquired proof of concept, CREATIvE will explore the kinetics of a low dose POP mixture release from an internal source of exposure, and most importantly will assess the toxic effects of such mixtures on other tissues and organs. After improvement of the experimental model, a mixture of twelve environmentally relevant POPs will be studied at low doses with the aim to better understand the consequences of POP mixture release from a unique internal source of exposure.