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.