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Updated: Jun 4, 2025
Isolation of Cortical Microglia with Preserved Immunophenotype and Functionality From Murine Neonates
Published on: January 30, 2014
A neurodegenerative cellular stress response linked to dark microglia and toxic lipid secretion
Anna Flury1, Leen Aljayousi1, Hye-Jin Park2
1Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA; Graduate Program in Biology, CUNY Graduate Center, New York, NY 10016, USA.
Abstract:
The brain's primary immune cells, microglia, are a leading causal cell type in Alzheimer's disease (AD). Yet, the mechanisms by which microglia can drive neurodegeneration remain unresolved. Here, we discover that a conserved stress signaling pathway, the integrated stress response (ISR), characterizes a microglia subset with neurodegenerative outcomes. Autonomous activation of ISR in microglia is sufficient to induce early features of the ultrastructurally distinct "dark microglia" linked to pathological synapse loss. In AD models, microglial ISR activation exacerbates neurodegenerative pathologies and synapse loss while its inhibition ameliorates them. Mechanistically, we present evidence that ISR activation promotes the secretion of toxic lipids by microglia, impairing neuron homeostasis and survival in vitro. Accordingly, pharmacological inhibition of ISR or lipid synthesis mitigates synapse loss in AD models. Our results demonstrate that microglial ISR activation represents a neurodegenerative phenotype, which may be sustained, at least in part, by the secretion of toxic lipids.
Insights
Microglia, the brain's immune cells, drive Alzheimer's disease (AD) via the integrated stress response (ISR). Inhibiting microglial ISR and toxic lipid production can reduce neurodegeneration and synapse loss in AD.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Microglia are key immune cells in the brain and implicated in Alzheimer's disease (AD) pathogenesis.
- The precise mechanisms by which microglia contribute to neurodegeneration are not fully understood.
Purpose of the Study:
- To investigate the role of the integrated stress response (ISR) in microglia and its contribution to Alzheimer's disease.
- To identify therapeutic targets for mitigating microglial-driven neurodegeneration.
Main Methods:
- Characterization of microglial subsets using the ISR pathway.
- Utilizing Alzheimer's disease models to study microglial ISR activation.
- Investigating the downstream effects of ISR on neuronal health and synapse integrity.
- Assessing the impact of ISR and lipid synthesis inhibition on disease pathology.
Main Results:
- A specific subset of microglia exhibiting activated ISR was identified, correlating with neurodegenerative outcomes.
- Autonomous ISR activation in microglia is sufficient to induce "dark microglia" and pathological synapse loss.
- Microglial ISR activation exacerbates AD pathologies and synapse loss, while inhibition ameliorates these effects.
- ISR activation in microglia promotes the secretion of toxic lipids, impairing neuronal homeostasis and survival.
Conclusions:
- Microglial ISR activation represents a distinct neurodegenerative phenotype in Alzheimer's disease.
- Inhibition of microglial ISR and associated toxic lipid synthesis offers a potential therapeutic strategy for AD.
- Targeting the ISR pathway in microglia may be crucial for preserving neuronal function and preventing synapse loss in AD.
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