Cellular pathogenesis of Alzheimer's disease

Area of Science:

• Neuroscience
• Biochemistry
• Pathology

Background:

• Paired helical filaments (PHFs) are key pathological hallmarks in Alzheimer's disease (AD).
• PHFs are composed of tau protein in a fibrillar, beta-pleated sheet conformation.
• Microtubules are essential for normal neuronal function and structure.

Purpose of the Study:

• To propose a mechanism for tau aggregation and its role in neurodegeneration.
• To elucidate the role of paired helical filaments and senile plaques in Alzheimer's disease pathogenesis.
• To investigate the potential function of apolipoprotein E4 in tau fibrillogenesis.

Main Methods:

• The study is theoretical, proposing a biochemical and cellular mechanism.
• It involves analyzing the proposed interactions between soluble tau, aggregated tau, and microtubules.
• The role of heteronucleants like senile plaques and apolipoprotein E4 is discussed.

Main Results:

• Nascent tau binding to beta-pleated sheet tau autocatalyzes further conformational change.
• Accumulation of proteolysis-resistant PHFs leads to microtubule instability and neuronal death.
• Senile plaques and apolipoprotein E4 may act as heteronucleants, promoting tau fibrillogenesis.

Conclusions:

• Progressive tau aggregation causes microtubule destabilization and neurodegeneration, central to Alzheimer's disease.
• Senile plaques and apolipoprotein E4 are implicated as catalysts in the pathological cascade of tau.
• This model provides a framework for understanding the molecular pathogenesis of Alzheimer's disease.