GRK2 contribution to the regulation of energy expenditure and brown fat function

Obesity is a major health problem and an important risk factor for the development of multiple disorders. Previous studies in our laboratory have revealed that down-regulation of GRK2 decreases age-related adiposity, but the physiological and molecular mechanisms underlying this outcome remain unclear. We evaluate whether the lean phenotype results from a direct effect of GRK2 on energy homeostasis. The study of white adipose tissue (WAT) in wild-type (WT) and GRK2+/− littermates showed a reduced expression of lipogenic enzymes and enhanced lipolytic rate in adult GRK2+/− mice. Moreover, hemizygous mice display higher energy expenditure and lower respiratory exchange ratio. Analysis of brown adipose tissue (BAT) from adult GRK2+/− mice showed a less deteriorated morphology associated with age compared to WT, which is correlated with a higher basal core temperature. BAT from young GRK2+/− mice showed an increase in gene expression of thermogenesis-related genes. Accordingly, hemizygous mice displayed bette...