Interplay between diet-induced obesity and chronic stress in mice: potential role of FKBP51.

While it is known that stress promotes obesity, the effects of stress within an obesogenic context are not so clear and molecular targets at the interface remain elusive. The FK506-binding protein 51 (FKBP51, gene: Fkbp5) has been identified as a target gene implicated in the development of stress-related psychiatric disorders and is a possible candidate for involvement in stress and metabolic regulation. The aims of the current study are to investigate the interaction between chronic stress and an obesogenic context and to additionally examine whether FKBP51 is involved in this interaction. For this purpose, male C57BL/6 mice were exposed to a high-fat diet for 8 weeks before being challenged with chronic social defeat stress. Herein, we demonstrate that chronic stress induces hypophagia and weight loss, ultimately improving features arising from an obesogenic context, including glucose tolerance and levels of insulin and leptin. We show that Fkbp5 expression is responsive to diet and stress in the hypothalamus and hippocampus respectively. Furthermore, under basal conditions, higher levels of hypothalamic Fkbp5 expression were related to increased body weight gain. Our data indicate that Fkbp5 may represent a novel target in metabolic regulation.