BACE1 mRNA expression in Alzheimer's disease postmortem brain tissue

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) is crucial for amyloid-beta (Aβ) peptide production, a key factor in Alzheimer's disease (AD) pathology.
• Previous studies indicate elevated BACE1 protein levels and activity in AD brains, but the underlying transcriptional regulation remains unclear.
• Understanding BACE1 mRNA expression patterns in neurodegenerative diseases is vital for elucidating AD pathogenesis.

Purpose of the Study:

• To investigate whether elevated BACE1 protein levels in Alzheimer's disease (AD) brains are associated with increased BACE1 mRNA expression.
• To compare BACE1 mRNA levels across different brain regions in control subjects, AD patients, and individuals with other neurodegenerative diseases like Parkinson's disease (PD) and dementia with Lewy bodies (DLB).
• To correlate BACE1 mRNA expression with glial and neuronal marker changes in AD progression.

Main Methods:

• RNA was extracted from five brain regions of control, AD, and PD/DLB groups.
• BACE1 mRNA levels were quantified using quantitative real-time PCR (qPCR) and analyzed with qbasePLUS software.
• Glial fibrillary acidic protein (GFAP) and neuron-specific enolase (NSE) mRNA levels were measured to assess glial and neuronal activity.

Main Results:

• BACE1 mRNA levels were significantly elevated in the medial temporal and superior parietal gyri of AD patients compared to PD/DLB and control groups.
• Superior frontal gyrus BACE1 mRNA levels were significantly increased in the PD/DLB group compared to AD and control groups.
• In AD, increased BACE1 mRNA correlated with reduced NSE and increased GFAP mRNA, suggesting a link to neuronal loss and glial activation.

Conclusions:

• Elevated BACE1 mRNA expression in specific brain regions of AD patients supports its role in AD pathogenesis.
• Increased BACE1 mRNA in remaining neuronal cells may contribute to elevated BACE1 protein levels and activity observed in AD-affected brain areas.
• Differential BACE1 mRNA expression patterns were observed between AD and PD/DLB groups, highlighting disease-specific molecular changes.