Research Article

Metabolic Brain Disease

, Volume 29, Issue 3, pp 729-736

First online:

mTOR-mediated hyperphosphorylation of tau in the hippocampus is involved in cognitive deficits in streptozotocin-induced diabetic mice

  • Shan WangAffiliated withDepartment of Pharmaceutical Engineering, College of Chemistry and Chemical Engineering, Central South University
  • , Shan-lei ZhouAffiliated withDepartment of Endocrinology, Xiang-Ya Hospital, Central South University
  • , Fang-yuan MinAffiliated withDepartment of Pharmaceutical Engineering, College of Chemistry and Chemical Engineering, Central South University
  • , Jin-ju MaAffiliated withDepartment of Endocrinology, Xiang-Ya Hospital, Central South University
  • , Xia-jie ShiAffiliated withDepartment of Endocrinology, Xiang-Ya Hospital, Central South University
  • , Erika BereczkiAffiliated withDepartment of Neurobiology, Care Sciences and SocietyKI-Alzheimer’s Disease Research Center, Karolinska Institutet
  • , Jing WuAffiliated withDepartment of Endocrinology, Xiang-Ya Hospital, Central South University Email author 

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Abstract

Abnormal levels of mammalian target of rapamycin (mTOR) signaling have been recently implicated in the pathophysiology of neurodegenerative diseases, such as Alzheimer’s disease (AD). However, the implication of mTOR in diabetes mellitus (DM)-related cognitive dysfunction still remains unknown. In the present study, we found that phosphorylated mTOR at Ser2448, phosphorylated p70S6K at Thr421/Ser424 and phosphorylated tau at Ser396 were significantly increased in the hippocampus of streptozotocin (STZ)-induced diabetic mice when compared with control mice. A low dose of rapamycin was used to elucidate the role of mTOR signaling in DM-related cognitive deficit. Rapamycin restored abnormal mTOR/p70S6K signaling and attenuated the phosphorylation of tau protein in the hippocampus of diabetic mice. Furthermore, the spatial learning and memory function of diabetic mice significantly impaired compared with control mice, was also reversed by rapamycin. These findings indicate that mTOR/p70S6K signaling pathway is hyperactive in the hippocampus of STZ-induced diabetic mice and inhibiting mTOR signaling with rapamycin prevents the DM-related cognitive deficits partly through attenuating the hyperphosphorylation of tau protein.

Keywords

mTOR Cognitive deficit Diabetic Rapamycin Tau