The prevalence of obesity and its comorbidities has reached pandemic proportions and its economic and social burden highlights the need to develop therapeutic strategies beyond traditional lifestyle interventions. It is now well established that the obese brain is stressed, and the hypothesis that endoplasmic reticulum (ER) stress in hypothalamic cells is causally linked to obesity and associated comorbidities has been well supported. We have identified a novel thioredoxin-like protein called SELENOT that regulates redox homeostasis. The genetic invalidation of SELENOT in mice is lethal in utero and the reduction of its expression in POMC neurons or beta-pancreatic cells, major sites of metabolic integration, causes an alteration of hormonal secretions. Conversely, administration of a peptide mimetic of SELENOT, named PSELT, attenuates obesity and hyperglycemia in a pilot study performed in mice. Our goal is to demonstrate that SELENOT is an important regulator of ER stress and POMC production associated with energy homeostasis, and that the SELENOT peptide we developed may represent a valuable therapeutic tool against obesity and type 2 diabetes. In particular, we would like to answer the following questions: 1. What are the molecular mechanisms underlying the regulation of ER stress by SELENOT? 2. What is the role of SELENOT in POMC neuron function? 3. What are the metabolic effects of the PSELT peptide and its mechanism of action. The data obtained will be essential in order to use the PSELT as a therapy against obesity and its comorbidities, which represent a priority issue for the French health system.

Obesity, insulin resistance, and type-2 diabetes (T2D) are growing health concerns, and the incidence and prevalence of these diseases are increasing worldwide. Beside dietary treatment, the current therapeutic strategies consist of 2 main types of products: those dealing with complications of obesity such as anti-diabetic or anti-cholesterol, and those altering the feeding behavior such as appetite suppressants. Among these, anorexigenic molecules derived from amphetamine and fenfluramine were recently banned from prescription because of side effects, reducing the potential for pharmacological treatment of obesity. While the availability of novel drugs, techniques, and surgical intervention has improved the survival rate of individuals with diabetes, its prevalence still rises. These alarming statistics underscore the need for research aimed at discovering novel therapeutic strategies for the prevention or treatment of these diseases. Thus, the need for a better understanding of how glucose homeostasis is regulated is compelling; as such information is essential to develop new strategies for safe and effective treatments for obesity and T2D. In this context, it is now well established that some neuropeptides play a key role in the control of food intake. In particular, neurons in the arcuate nucleus of the hypothalamus that express NPY and those that synthesize a-MSH exert opposite effects on food intake. Partner 1 has previously demonstrated that central administration of the gliopeptide ODN, belonging to the endozepines family, causes a dramatic decrease in food intake combined with an irreversible loss of body weight. In line with recent advances in neuron-glia communication showing that glia is involved in the detection of various physiological parameters, we hypothesize that glial cells bordering the 3rd and the 4th ventricles (tanycytes and vagliocytes) are able to sense the local glycemia to inform the hypothalamus and the dorsal vagal complex (DVC) on systemic glucose homeostasis by using ODN signalling. Preliminary results from Partner 2 show that local injection of ODN-isoactive fragment in the 4th ventricle decreases food intake. Moreover, injection of the same peptide in the 3rd ventricle prevents fasting-mediated plasticity of the tanycytic barrier suggesting that ODN signaling modulates the exchanges between the hypothalamus and the CSF (preliminary data, Partner 3). Collectively, our present results converge to the view that ODN is the key-factor of a novel feedback loop controlling whole-body glucose homeostasis. This project represents an integrated approach towards understanding the mechanisms of the gliopeptide signaling in the CNS in order to contribute to innovative therapies for the treatment of obesity and/or diabetes. The multidisciplinary approach of the project will lead to significant advances at the junction of three fields: i) the ODN system, ii) the glio-neuronal communication and iii) the regulation of glucose homeostasis. The consortium federates the efforts of 3 internationally recognized teams strongly involved on these concepts. Partner 1, Inserm U982 (Rouen), has an international reputation in the field of neuropeptides, neuroendocrinology and neuroscience, Partner 2, PPSN (ex UMR 6231, Marseille), is a new team with an international reputation in autonomic neuroscience, feeding behavior and glucose sensing and Partner 3, Inserm U1172 (Lille), has an international expertise in the impact of peripheral hormones on hypothalamic development and function. The combination of the 3 partner’s skills will provide a research framework going from molecular neurobiology to animal models with potential output to human clinic. Their researches will shed light on novel pathway of glucose sensing in the brain and could therefore possibly lead to identification of novel targets for the treatment of metabolic disorders.

Cystic fibrosis (CF) patients often died from the consequences of recurrent chronic respiratory infections mostly due to Pseudomonas aeruginosa. These infections are not controlled due to frequent antibiotic-resistance, a tolerance to antimicrobials due to bacteria forming biofilms. Since new antimicrobial drugs are not emerging despite strong research, we urgently need complementary approaches improving the activity of antimicrobial drugs such as antibiofilm agents. We have recently identified the strong ability of natriuretic peptides (NPs) to disperse established biofilm and to facilitate the elimination of chronic infection by P. aeruginosa in mice model, after binding to a specific bacterial target. Interestingly, NPs potentiates the antibacterial activity of antibiotic and we have identified members of this family with different activity allowing to define a structure-activity relationship. The aim of APPOLON project is to generate the ideal drug candidate as a peptide derived from NPs for the treatment of recurrent infection by P. aeruginosa in CF patient. For this we will 1) Identify, in vitro among all available NPs, the most active peptide against established biofilms; 2) Modify the most active peptides to optimize their efficacy and their bioavailability; 3) Validate the effect of the two most active modified peptides in WT and in Scnn1b-Tg mice which mimics CF; 4- Detail the mechanism of action of peptides on bacterial biofilms and its impact on bacteria fitness. The results obtained in this project will allow to rapidly propose a drug candidate for the eradication of chronic respiratory infections. This soft approach will probably avoid the risk of setting up a resistance mechanism to this drug. This is essential for CF patients although this might have some applications for intubated patients in intensive care units and with acute exacerbations of chronic obstructive pulmonary disease (COPD).

In animals, neuropeptides working either as neuromodulators or neurohormones play a crucial role in the elaboration of adapted physiological and behavioural responses to environmental constrains. The present project aims to investigate the evolution of neuroendocrine systems and to explore their role in the regulation and the plasticity of biological cycles and reproduction in marine non-conventional animal models (a coral, two mollusc representatives and two eel species) of phylogenetic, ecological and economical relevance. This project will bring together, physiologists, molecular and evolutionary biologists, structural biochemists and chemists. It is based on the development of cutting edge methodologies to allow the comparison of the structure and the functionality of key neuroendocrine pathway components regulating reproduction and associated processes. It will provide the bases of their responses to environmental factors. This multidisciplinary and integrated study will lead to the production of significant knowledge on: (1) The structure and diversity of neuroendocrine systems in phylogenetically distant marine species. (2) The origin and evolution of neuroendocrine systems in Bilateria and Eumetazoa. (3) The co-evolution of functional neuropeptide/receptor pairs. (4) The three-dimensional structure of neuropeptides in the vicinity of membranes. (5) The Structure-activity relationships of some relevant ligand/receptor pairs. (6) The nature, the expression and the role of neuropeptides involved in the control of reproduction in different marine species, the conservation or divergence of these regulatory pathways during evolution. (7) The influence of global changes in particular of temperature on the structure of endocrine pathways, their potential consequences in terms of physiological adaptation of the species studied. The consortium federates the forces of internationally recognized teams with expertise in the fields of evolutionary and comparative neuroendocrinology. The teams have in the past experienced fruitful cross collaborations leading to outstanding scientific results. Partner 1 (UMR 7208, Caen-Paris) has an international reputation in the field of comparative neuroendocrinology of marine species (fish, shellfish), partner 2 (U 982, Mont-Saint-Aignan) holds a solid international recognition in the field of neuropeptides, neuroendocrinology and neuroscience, partner 3 (UMR 7221, Paris) is an internationally recognized team in the studies on the evolution of endocrine systems, Partner 4 (UMR 6226, Rennes) has international expertise in NMR structural study of peptides, partner 5 (NTOU, Taiwan) is a team with an international reputation for its work in the field of reproductive endocrinology of fish and coral, partner 6 (NKMU, Taiwan) has an expertise in fish reproductive endocrinology and its application in aquaculture. Besides the acquisition of fundamental knowledge about the regulation of physiological functions in marine species of economic interest, such research may open interesting perspectives in subjects related to aquaculture, fisheries and environment.

Lung cancer is the leading cause of cancer in France and worldwide. Recent therapeutic advances have come from identification of molecular alterations associated with efficacy of targeted therapies. Thus, discovery of new actionable molecular alterations is a major challenge. Recently, mutations affecting the gene encoding the MET receptor have been detected in lung cancers, raising several clinical and scientific questions. These mutations affect splice sites of exon 14 and are highly heterogeneous which makes them difficult to detect. They induce exon 14 skipping, which functional consequences are still poorly understood. Importantly, these mutations are associated with efficacy of MET tyrosine kinase inhibitors (TKI) which represents a promising therapeutic opportunity. However, as for other targeted therapies, efficacy of MET TKI may be limited due to emergence of resistance which mechanisms are totally unknown so far. In the first part of this study, we will develop new diagnostic tools for detecting mutations leading to exon 14 skipping. We will develop techniques that can be easily transposed into routine practice, based on PCR fragment analysis and SnapShot technology, and high throughput techniques such as Next-Generation Sequencing (NGS). Moreover, we will develop an alternative to genomic techniques based on immunohistochemistry through the development of an exon 14 specific antibodies. We will compare these different methods of detection on several cohorts including unselected lung cancers, lung cancers with high MET overexpression and pulmonary sarcomatoid carcinomas. We will also have access to tumor samples from clinical trials evaluating MET TKI in patients with MET exon 14 mutations (MERCK phase II trial). In the second part of this study, we will address the functional consequences of exon 14 skipping. Exon 14 is known to harbor 3 different negative regulation sites. We will test the respective contribution of each of these regulation sites. To do so, we will use lentiviral infection with vectors harboring MET mutations affecting each of the regulation sites or all three of them. We will evaluate biological responses in the different cell lines along with sensitivity to MET TKI including tepotinib, a selective MET TKI, through collaboration with MERCK. We will also xenograft these cell lines in mice to evaluate tumor growth. In parallel, similar studies will be performed to investigate the effects of mutating exon 14 regulatory sites on the endogenous MET gene using CRISPR-barcoding technology. In the third part of this study, we will aim at identifying mechanisms of resistance to MET TKI emerging from MET exon 14 skipping cell lines and tumors. First we will generate resistant cell lines by exposing HS746T and H596 cell lines, known to harbor MET exon 14 skipping mutations, to increasing doses of MET TKI. We will also xenograft these cell lines and make them resistant to MET TKI through exposure to intermittent treatment cycles. We will compare parental and resistant cell lines regarding signaling pathways and genomic profile, including full-length MET sequencing, whole-exome sequencing and CGH array. Finally, we will aim at validating the identified mechanisms of resistance on tumor samples obtained from patients progressing upon MET TKI in the context of clinical trials (MERCK phase II trial). Overall, this study will improve detection of MET exon 14 mutations, understanding of functional consequences of exon 14 skipping and identification of mechanisms of resistance to MET TKI. This will facilitate selection of patients who may benefit from MET TKI and development of innovative therapeutic strategies to overcome resistance once progression has occurred.