A shared disease-associated oligodendrocyte signature among multiple CNS pathologies

Area of Science:

• Neuroscience
• Cell Biology
• Pathology

Background:

• Alzheimer's disease (AD) is a complex neurodegenerative disorder affecting various brain cell populations.
• Understanding non-neuronal cell responses is crucial for deciphering AD pathogenesis.
• Oligodendrocytes, traditionally known for myelination, may play roles beyond this in disease states.

Purpose of the Study:

• To comprehensively map non-immune, non-neuronal cell populations in wild-type and AD model mouse brains using single-cell transcriptomics.
• To identify novel cell states associated with neurodegenerative conditions.
• To investigate the role and prevalence of these identified cell states in different central nervous system pathologies.

Main Methods:

• Single-cell RNA sequencing to profile brain cells from wild-type and 5xFAD AD model mice.
• In vitro experiments to assess the effect of amyloid-beta on oligodendrocyte signature.
• Quantitative spatial analysis of mouse and human postmortem brain tissues.
• Correlation analysis between oligodendrocyte marker expression and cognitive decline in human subjects.

Main Results:

• Identification of a novel oligodendrocyte subpopulation, termed disease-associated oligodendrocytes (DOLs), which increases with brain pathology.
• DOLs emerge later than amyloid plaque deposition and are not solely induced by amyloid-beta.
• DOLs are present in various neurological conditions, including tauopathy, other neurodegenerative diseases, and autoimmune inflammatory conditions, indicating a conserved response.
• A key DOL marker (SERPINA3N/SERPINA3) is found in damaged cortical areas and near amyloid plaques in both mouse and human brains.
• Higher expression of this marker correlates with cognitive decline in human Alzheimer's disease patients.

Conclusions:

• Oligodendrocytes exhibit a shared pathological signature across diverse central nervous system conditions.
• Disease-associated oligodendrocytes represent a common cellular response to severe brain insults.
• The identified DOL marker SERPINA3N/SERPINA3 may serve as a potential biomarker for disease progression and cognitive impairment in neurological disorders.