High glucose forces a positive feedback loop connecting ErbB4 expression and mTOR/S6K pathway to aggravate the formation of tau hyperphosphorylation in differentiated SH-SY5Y cells

Publication date: July 2018
Source:Neurobiology of Aging, Volume 67
Author(s): Sheng-Dan Nie, Xin Li, Can-E. Tang, Fang-Yuan Min, Xia-Jie Shi, Liang-Yan Wu, Shan-Lei Zhou, Zi Chen, Jing Wu, Tao Song, Zhi-Jie Dai, Jiao Zheng, Jia-jia Liu, Shan Wang
High glucose (HG)-induced mammalian target of rapamycin (mTOR) overactivation acts as a signaling hub for the formation of tau hyperphosphorylation, which contributes to the development of diabetes-associated cognitive deficit. How HG induces the sustained activation of mTOR in neurons is not clearly understood. ErbB4, a member of the receptor tyrosine kinase family, plays critical roles in development and function of neural circuitry, relevant to behavioral deficits. Here, we showed HG-induced ErbB4 overexpression in differentiated SH-SY5Y cells and primary hippocampal neurons and hippocampal pyramidal neurons of streptozotocin-induced diabetic rats. Inhibition of ErbB4 signaling prevented the HG-induced activation of mTOR/S6K signaling to suppress tau hyperphosphorylation. In contrast, ErbB4 overexpression increased the activation of mTOR/S6K signaling, resulting in tau hyperphosphorylation similar to HG treatment. We also demonstrated that HG upregulated the expression of ErbB4 at a mTOR-dependent posttranscriptional level. Together, our results provide the first evidence for the presence of a positive feedback loop for the sustained activation of mTOR involving overexpressed ErbB4, leading to the formation of tau hyperphosphorylation under HG condition. Therefore, ErbB4 is a potential therapeutic target for diabetes-associated neurodegeneration.



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