Early neuronal reprogramming and cell cycle reentry shape Alzheimer's disease progression

Area of Science:

• Neuroscience
• Genomics
• Pathology

Background:

• Alzheimer's disease (AD) is a progressive neurodegenerative disorder marked by cognitive decline, synaptic dysfunction, and neuronal loss.
• Recent studies highlight specific neuronal vulnerabilities and glial responses in AD brains, but the precise timing and coordination of these changes remain unclear.

Purpose of the Study:

• To investigate early transcriptional changes in neurons across the Alzheimer's disease (AD) spectrum.
• To understand the coordination between neuronal and glial responses in AD pathogenesis.

Main Methods:

• Utilized non-negative matrix factorization on single-nucleus RNA sequencing data from 437 prefrontal cortex samples spanning no cognitive impairment to AD dementia.
• Validated findings using independent snRNA-seq, proteomics, and ELISA datasets.

Main Results:

• Identified early, coordinated transcriptional shifts in all neuronal subtypes preceding clinical symptoms.
• Observed rapid modulation of synaptic genes in AD neurons, converging into two distinct programs: oxidative stress/apoptosis (vulnerable neurons) and DNA damage/cell-cycle reentry (resilient neurons).
• Demonstrated a close link between neuronal reprogramming and glial responses, differentiating AD from normal brain aging.

Conclusions:

• Neuronal reprogramming occurs early in Alzheimer's disease, preceding cognitive decline.
• Distinct neuronal response programs (stress vs. repair) emerge, influenced by subtype vulnerability.
• Neuro-glial coordinated reprogramming is a key factor in the Alzheimer's disease cascade and disease outcomes.