Affiliations: [a] Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| [b] Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| [c] Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| [d] Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
Correspondence:
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Correspondence to: Jian-Zhi Wang, Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. Tel.: +86 027 83693881; E-mail: wangjz@mail.hust.edu.cn.
Abstract: Background:Recent studies show that an increased T217-phosphorylation of tau in plasma could diagnose AD at an early stage with high accuracy and high specificity, while the potential toxic role of tau T217-phosphorylation is not known. Objective:To study the potential toxic role of tau T217-phosphorylation. Methods:We performed stereotactic brain injection, behavioral testing, immunohistochemistry and immunofluorescence, western blotting, Golgi staining, in vitro recombinant tau polymerization, and other measurements. Results:We first constructed tau T217-wild-type (T217), T217-phospho-mimic (T217E), and T217-non-phospho-mimic (T217A) plasmids or their virus vectors on the basis of wild-type tau. We found that expressing tau-T217E induced a significantly increased tau phosphorylation at multiple AD-associated sites with inhibited proteolysis and increased cleavage/fibrillization of tau, while expressing tau-T217A abolished the above changes of tau both in vitro and in vivo. By mutating T217E on tau-P301L, a dominant mutation identified in patients with frontotemporal dementia, we did not observe significant exacerbation of tau-P301L phosphorylation and cognitive impairment although the increased tau cleavage and propagation were shown. Conclusion:T217-phosphorylation exacerbates wild-type tau hyperphosphorylation with aggravated tau cleavage/fibrillization and cognitive impairments, while overexpressing T217E on the basis P301L does not exacerbate tau phosphorylation or the P301L-induced cognitive deficits, although it aggravates tau cleavage and propagation.
