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Microglial P2Y12 mediates chronic stress-induced synapse loss in the prefrontal cortex and associated behavioral
Justin L Bollinger1, David T Dadosky1, James K Flurer1
1Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
Abstract:
Chronic unpredictable stress (CUS) drives microglia-mediated neuronal remodeling and synapse loss in the prefrontal cortex (PFC), contributing to deficits in cognition and behavior. However, it remains unclear what mechanisms guide microglia-neuron interactions in stress. Evidence indicates that neuronal activity-dependent purinergic signaling directs microglial processes and synaptic engagement via P2Y12, a purinergic receptor exclusively expressed by microglia in the brain. Stress alters excitatory neurotransmission in the PFC, thus we aimed to determine if P2Y12 signaling promotes functional changes in microglia in chronic stress. Here we used genetic ablation of P2Y12 (P2ry12-/-) or pharmacological blockade (clopidogrel, ticagrelor) to examine the role of purinergic signaling in stress-induced microglia-neuron interaction. Multiple behavioral, physiological, and cytometric endpoints were analyzed. Deletion of P2Y12 led to a number of fundamental alterations in the PFC, including the heightened microglial number and increased dendritic spine density. Flow cytometry revealed that microglia in P2ry12-/- mice had shifts in surface levels of CX3CR1, CSF1R, and CD11b, suggesting changes in synaptic engagement and phagocytosis in the PFC. In line with this, pharmacological blockade of P2Y12 prevented CUS-induced increases in the proportion of microglia with neuronal inclusions, limited dendritic spine loss in the PFC, and attenuated alterations in stress coping behavior and working memory function. Overall, these findings indicate that microglial P2Y12 is a critical mediator of stress-induced synapse loss in the PFC and subsequent behavioral deficits.
Insights
Microglial P2Y12 receptors mediate synapse loss in the prefrontal cortex (PFC) during chronic unpredictable stress (CUS). Blocking P2Y12 signaling prevents stress-induced synaptic damage and cognitive deficits.
Area of Science:
- Neuroscience
- Cell Biology
- Stress Research
Background:
- Chronic unpredictable stress (CUS) causes synapse loss in the prefrontal cortex (PFC), impairing cognition.
- Microglia, the brain's immune cells, interact with neurons and synapses, but the mechanisms guiding these interactions during stress are unclear.
- Purinergic signaling, specifically via the P2Y12 receptor on microglia, influences microglial processes and synaptic engagement.
Purpose of the Study:
- To investigate the role of microglial P2Y12 purinergic signaling in mediating neuronal and behavioral changes induced by chronic unpredictable stress (CUS).
- To determine if P2Y12 signaling contributes to stress-induced synapse loss in the prefrontal cortex (PFC).
Main Methods:
- Genetic ablation of the P2Y12 receptor (P2ry12-/- mice) and pharmacological blockade (clopidogrel, ticagrelor) were used.
- Behavioral tests, physiological measurements, and flow cytometry were employed to assess microglial function and neuronal integrity.
- Analysis focused on microglial number, dendritic spine density, surface marker expression, and neuronal inclusions.
Main Results:
- P2Y12 deletion altered microglial number and increased dendritic spine density in the PFC.
- P2Y12 deficiency shifted microglial surface marker levels (CX3CR1, CSF1R, CD11b), suggesting altered synaptic engagement and phagocytosis.
- Pharmacological P2Y12 blockade prevented CUS-induced synapse loss, reduced neuronal inclusions in microglia, and attenuated behavioral deficits in stress coping and working memory.
Conclusions:
- Microglial P2Y12 receptor is a critical mediator of synapse loss in the PFC during chronic stress.
- Targeting P2Y12 signaling offers a potential therapeutic strategy for stress-induced cognitive and behavioral impairments.
