Mitochondrial dysfunction in a transgenic mouse model expressing human amyloid precursor protein (APP) with the...

Area of Science:

• Neuroscience
• Mitochondrial Biology
• Alzheimer Disease Research

Background:

• Amyloid-beta (Aβ) peptide accumulation in the brain is a key factor in Alzheimer disease (AD) pathogenesis.
• Mitochondrial dysfunction and oxidative stress are implicated in AD, but their early role remains under investigation.

Purpose of the Study:

• To investigate the correlation between amyloid-beta deposition and mitochondrial function in a transgenic mouse model of Alzheimer disease.
• To examine mitochondrial dysfunction in TgAPParc mice carrying the Arctic mutation in amyloid precursor protein (APP).

Main Methods:

• Utilized a transgenic mouse model (TgAPParc) expressing human APP with the Arctic mutation.
• Assessed mitochondrial membrane potential (MMP), reactive oxygen species (ROS) production, and oxidative DNA damage.
• Measured cytochrome c oxidase (COX) activity in mouse mitochondria.

Main Results:

• Evidence of mitochondrial dysfunction, including decreased MMP, increased ROS, and oxidative DNA damage, was found at 6 months of age with mild Aβ deposition.
• More severe mitochondrial abnormalities and significantly decreased COX activity were observed in 24-month-old mice with extensive Aβ pathology.
• This study provides the first evidence of mitochondrial dysfunction in transgenic mice with an Arctic APP mutation.

Conclusions:

• Mitochondrial dysfunction is an early event in the pathogenesis of Alzheimer disease, preceding significant amyloid-beta plaque formation.
• Oxidative stress and impaired mitochondrial function are closely linked to amyloid-beta deposition in the TgAPParc mouse model.
• Findings support the hypothesis that mitochondrial dysfunction is a critical early contributor to Alzheimer disease development.