Fis1-induced mitochondrial fission and glucose metabolism in hepatocytes

Responsable : David Jacobi
Equipe V : Rythmes mitochondriaux nycthéméraux et maladies métaboliques

Ce stage est ouvert aux étudiants du Master2 BBRT de l'Université de Nantes.

Résumé du projet

The adaptation of energy substrate utilisation to the daily feeding/fasting cycles is called metabolic flexibility. We showed that disruption of the hepatic circadian clock in mice renders mitochondria non-adaptive to the daily nutritional cues, leading to oxidative stress and insulin resistance. These anomalies were corrected by hepatic overexpression of the mitochondrial fission protein FIS1, pointing out to an unknown role for FIS1 in metabolic flexibility.
Hypothesis: In hepatocytes, FIS1, which is normally induced during the fed state, participates to metabolic flexibility through repression of gluconeogenesis.
Proposed work: Establish FIS1 effects on hepatic glucose metabolism and whether these effects are nutrient and/or reactive oxygen species (ROS) dependent.
Methods: Fis1 gain or loss of function experiments (AdFis1 or AdShFis1) will be carried out in murine primary hepatocytes. We will measure gluconeogenic genes expression (RT-qPCR), glucose production (glucose oxidase reaction), glycogen accumulation, insulin sensitivity (study of AKT phosphorylation by western-blot), and ROS production (Electron Paramegnetic Resonance Spectrometry). Experiments will be repeated in varying nutritional conditions (glucose 1-4,5 g/L and palmitate 0-300 µmol/L). ROS dependency will be studied by up or down-regulating ROS production (H2O2 or mitochondrial ROS scavengers MitoTEMPO, respectively).
Project relevance: the project can open avenues in treating type 2 diabetes, a pathology typified by deregulated hepatic glucose production.

Option à laquelle est associée ce projet : Cardiovasculaire et Facteurs de Risque