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In Vitro Aggregation Assays Using Hyperphosphorylated Tau Protein
Published on: January 2, 2015
Homocysteine induces tau hyperphosphorylation in rats
Yougen Luo1, Xinwen Zhou, Xifei Yang
1Department of Pathophysiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Neuroreport
|November 17, 2007
Summary
High homocysteine (Hcy) levels may elevate Alzheimer's disease risk by promoting tau hyperphosphorylation. This study found Hcy reduced protein phosphatase-2A, a key enzyme in tau regulation.
Area of Science:
- Neuroscience
- Biochemistry
- Pathology
Background:
- Elevated homocysteine (Hcy) is linked to increased Alzheimer's disease (AD) risk.
- The precise molecular mechanisms connecting Hcy to AD pathogenesis remain unclear.
- Tau protein hyperphosphorylation is a hallmark of neurodegenerative diseases like AD.
Purpose of the Study:
- To investigate the impact of Hcy on tau phosphorylation in a rat model.
- To explore the role of protein phosphatase-2A (PP-2A) in Hcy-induced tau alterations.
Main Methods:
- Intracerebroventricular injection of Hcy into rat brains.
- Western blot analysis to quantify hyperphosphorylated tau levels (PHF-1, tau-1 epitopes).
- Measurement of protein phosphatase-2A catalytic subunit (PP-2Ac) levels.
Main Results:
- Hcy injection significantly increased hyperphosphorylated tau at PHF-1 and tau-1 epitopes at 6, 9, and 12 hours post-injection.
- Tau phosphorylation levels returned to baseline by 24 hours.
- Hcy administration markedly reduced the levels of PP-2Ac compared to control.
Conclusions:
- Homocysteine may induce tau hyperphosphorylation through a mechanism involving the reduction of PP-2Ac.
- These findings suggest a potential pathway linking Hcy to Alzheimer's disease pathology.
- Targeting PP-2A or modulating Hcy levels could be therapeutic strategies for AD.
