Mitochondrial FOXO3a is involved in amyloid β peptide-induced mitochondrial dysfunction

Area of Science:

• Neuroscience
• Cell Biology
• Biochemistry

Background:

• Mitochondrial dysfunction is a key feature of Alzheimer's disease (AD) neurotoxicity.
• The exact mechanisms of amyloid β peptide (Aβ)-induced mitochondrial impairment remain unclear.
• Forkhead box O3a (FOXO3a) is known to be present in neuronal mitochondria.

Purpose of the Study:

• To investigate the role of mitochondrial FOXO3a in Aβ-induced mitochondrial dysfunction in neuronal cells.
• To elucidate the molecular mechanisms linking Aβ, FOXO3a, and mitochondrial impairment.

Main Methods:

• Utilized HT22 murine hippocampal neuronal cells and primary hippocampal neurons.
• Examined Aβ-induced changes in FOXO3a phosphorylation and mitochondrial translocation.
• Assessed FOXO3a association with mitochondrial DNA (mtDNA).
• Measured cytochrome c oxidase subunit 1 (COX1) expression and COX activity.
• Evaluated mitochondrial function via MTT conversion, ATP production, and COX activity.
• Employed FOXO3a knockdown (FOXO3a-KD) to assess its functional significance.

Main Results:

• Aβ induced dephosphorylation and mitochondrial translocation of FOXO3a.
• Aβ enhanced FOXO3a binding to mtDNA, leading to reduced COX1 expression and COX activity.
• Aβ-induced mitochondrial dysfunction (decreased MTT conversion, ATP production, COX activity) was attenuated by FOXO3a-KD.
• FOXO3a plays a critical role in mediating Aβ-induced mitochondrial dysfunction.

Conclusions:

• FOXO3a is involved in the mechanism of Aβ-induced mitochondrial dysfunction in neurons.
• Aβ-induced neurotoxicity involves FOXO3a's interaction with mtDNA, impacting mitochondrial respiration.
• Modulating FOXO3a activity presents a potential therapeutic avenue for Alzheimer's disease.