Microglia--a wrench in the running wheel?

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Physical activity and environmental enrichment promote neurogenesis and may slow Alzheimer's disease (AD) progression.
• Familial forms of AD are linked to mutations in specific genes, including those encoding Presenilin 1 (PS1).

Purpose of the Study:

• To investigate how Presenilin 1 (PS1) variants, associated with familial Alzheimer's disease, affect the neurogenic and regenerative benefits of physical activity.
• To explore the role of microglia in mediating the interaction between PS1 variants and activity-induced brain plasticity.

Main Methods:

• Utilized mouse models expressing familial AD-linked PS1 variants.
• Assessed neurogenesis and behavioral changes in response to physical activity and environmental enrichment.
• Analyzed changes in microglia populations and their secreted factors.

Main Results:

• Expression of familial AD-associated PS1 variants counteracted the positive effects of physical activity and environmental enrichment on neurogenesis.
• PS1 variants altered the phenotype and function of resident microglia.
• Microglia-secreted factors were implicated in mediating the inhibitory effects of PS1 variants.

Conclusions:

• Familial AD-linked PS1 variants can impair the brain's regenerative capacity, even under conditions that normally promote it, such as physical activity.
• Modulating microglia activity and their secreted factors may represent a therapeutic strategy for Alzheimer's disease.