Extensive nuclear sphere generation in the human Alzheimer's brain

Area of Science:

• Neuroscience
• Cell Biology
• Biochemistry

Background:

• Nuclear spheres are protein aggregates involving FE65, TIP60, and BLM.
• Amyloid precursor protein (APP) is thought to modulate nuclear sphere generation through cleavage or phosphorylation.

Purpose of the Study:

• To investigate the existence of nuclear spheres in the human brain.
• To explore the regulatory mechanisms of nuclear sphere generation.
• To determine the association of nuclear spheres with Alzheimer's disease (AD).

Main Methods:

• Immunohistochemistry was used to detect nuclear spheres in human brain samples.
• Cell culture experiments were conducted to study sphere generation regulation.
• Co-staining techniques identified cell types affected by nuclear spheres.

Main Results:

• Nuclear spheres were found to be significantly enriched in the frontal cortex of AD patients compared to controls.
• Neurons were distinctly affected by nuclear spheres, while astrocytes were not.
• Nuclear spheres were predominantly observed in neurons lacking APP phosphorylation at threonine 668.
• JNK3-mediated APP phosphorylation reduced the number of sphere-positive cells in cell cultures.

Conclusions:

• Nuclear spheres represent a novel, APP-derived hallmark in Alzheimer's disease.
• Their enrichment in AD brains suggests a crucial role in neurodegenerative mechanisms.
• The findings highlight a potential new avenue for understanding and diagnosing AD.