Deletion of Arrb2 Down-regulates Autophagy in the Mouse Hippocampus via Akt-mTOR Pathway Activation

Abstract

The cytoplasmic multifunctional adaptor protein β-arrestin 2 (Arrb2) is involved in the occurrence of various nervous system diseases, such as Alzheimer's disease and Parkinson's disease. Previous laboratory studies have shown that the expression and function of the Arrb2 gene was increased in valproic acid-induced autistic mice models. However, few reports have examined the possible role of Arrb2 in the pathogenesis of autism spectrum disorder. Therefore, Arrb2-deficient (Arrb2−/−) mice were further studied to uncover the physiological function of Arrb2 in the nervous system. In this study, we found that Arrb2−/− mice had normal behavioral characteristics compared with wild-type mice. The autophagy marker protein LC3B was decreased in the hippocampus of Arrb2−/− mice compared to wild-type mice. Western blot analysis revealed that deletion of Arrb2 caused hyperactivation of Akt-mTOR signaling in the hippocampus. In addition, abnormal mitochondrial dysfunction was observed in Arrb2−/− hippocampal neurons, which was characterized by a reduction in mitochondrial membrane potential and adenosine triphosphate production and an increase in reactive oxygen species levels. Therefore, this study elucidates the interaction between Arrb2 and the Akt-mTOR signaling pathway and provides insights into the role of Arrb2 in hippocampal neuron autophagy.