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Updated: Aug 1, 2025
Isolation of Region-specific Microglia from One Adult Mouse Brain Hemisphere for Deep Single-cell RNA Sequencing
Published on: December 3, 2019
Single-cell and spatial RNA sequencing identify perturbators of microglial functions with aging
Yifei Dong1, Rajiv W Jain1, Brian M Lozinski1
1Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada.
Abstract:
Microglia are the immune sentinels of the central nervous system with protective roles such as the removal of neurotoxic oxidized phosphatidylcholines (OxPCs). As aging alters microglial function and elevates neurological disability in diseases such as multiple sclerosis, defining aging-associated factors that cause microglia to lose their custodial properties or even become injurious can help to restore their homeostasis. We used single-cell and spatial RNA sequencing in the spinal cord of young (6-week-old) and middle-aged (52-week-old) mice to determine aging-driven microglial reprogramming at homeostasis or after OxPC injury. We identified numerous aging-associated microglial transcripts including osteopontin elevated in OxPC-treated 52-week-old mice, which correlated with greater neurodegeneration. Osteopontin delivery into the spinal cords of 6-week-old mice worsened OxPC lesions, while its knockdown in 52-week-old lesions attenuated microglial inflammation and axon loss. Thus, elevation of osteopontin and other transcripts in aging disorders including multiple sclerosis perturbs microglial functions contributing to aging-associated neurodegeneration.
Insights
Aging impairs microglia, the brain's immune cells, leading to neurodegeneration. Osteopontin elevation in aging mice exacerbates damage, suggesting it as a target for restoring microglial function and treating neurological disorders.
Area of Science:
- Neuroscience
- Immunology
- Aging Research
Background:
- Microglia act as central nervous system immune sentinels, crucial for clearing neurotoxic substances like oxidized phosphatidylcholines (OxPCs).
- Aging impairs microglial function, increasing susceptibility to neurological diseases such as multiple sclerosis and contributing to disability.
Purpose of the Study:
- To investigate aging-driven changes in microglial function and gene expression.
- To identify factors contributing to microglial dysfunction and neurodegeneration in aging.
Main Methods:
- Single-cell and spatial RNA sequencing were employed on mouse spinal cords at young (6-week-old) and middle-aged (52-week-old) stages.
- Oxidized phosphatidylcholine (OxPC) injury models were used to assess microglial responses in young and aged mice.
- Osteopontin's role was evaluated through direct delivery and knockdown experiments.
Main Results:
- Aging significantly altered microglial transcriptomes, with osteopontin notably elevated in middle-aged mice after OxPC injury.
- Elevated osteopontin levels correlated with increased neurodegeneration.
- Osteopontin exacerbated OxPC-induced lesions in young mice and contributed to microglial inflammation and axon loss in aged mice.
Conclusions:
- Osteopontin is an aging-associated microglial transcript that impairs their protective functions.
- Elevated osteopontin contributes to aging-associated neurodegeneration and multiple sclerosis pathology.
- Targeting osteopontin may restore microglial homeostasis and mitigate neurodegenerative processes.
