Partial microglial depletion through inhibition of colony-stimulating factor 1 receptor improves synaptic plasticity and cognitive performance in aged mice

2025/02/14 by Luisa Strackeljan, David Baidoe-Ansah, David Baidoe‐Ansah +5 · 3 citations
Neuroscience · #Neuroinflammation and Neurodegeneration Mechanisms #Neurological Disease Mechanisms and Treatments #Neurogenesis and neuroplasticity mechanisms

paper · doi:10.1016/j.expneurol.2025.115186

Abstract

Microglia depletion, followed by repopulation, improves cognitive functions in the aged mouse brain. However, even temporal ablation of microglia puts the brain at a high risk of infection. Hence, in the present work, we studied if the partial reduction of microglia with PLX3397 (pexidartinib), an inhibitor of the colony-stimulating factor 1 receptor (CSF1R), could bring similar benefits as reported for microglia ablation. Aged (two-years-old) mice were treated with PLX3397 for a total of 6 weeks, which reduced microglia numbers in the hippocampus and retrosplenial cortex (RSC) to the levels seen in young mice and resulted in layer-specific ablation in the expression of microglial complement protein C1q mediating synaptic remodeling. This treatment boosted long-term potentiation in the CA1 region and improved performance in the hippocampus-dependent novel object location recognition task. Although PLX3397 treatment did not alter the number or total intensity of Wisteria floribunda agglutinin-positive perineuronal nets (PNNs) in the CA1 region of the hippocampus, it changed the fine structure of PNNs. It also elevated the expression of perisynaptic proteoglycan brevican, presynaptic vGluT1 at excitatory synapses, and vGAT in inhibitory ones in the CA1 stratum radiatum . Thus, targeting the CSF1R may provide a safe and efficient strategy to boost synaptic and cognitive functions in the aged brain. • PLX3397, an inhibitor of CSF1R, normalizes number of microglia in aged mice. • PLX3397 improves performance of aged mice in the novel object location task. • PLX3397 improves long-term potentiation in the CA1 hippocampal region. • PLX3397 reduces expression of C1q, a cue driving synaptic loss by microglia. • PLX3397 increases expression of key perisynaptic ECM and synaptic molecules.

Cited by

• Experience-dependent control of synaptic remodeling and structural plasticity by glia. [europepmc]
• Reduced synaptic tagging by complement protein C3 is associated with elevated extracellular matrix in the middle-aged cerebellum of mice. [europepmc]
• Cerebellar Resistance to Amyloid Plaque Deposition and Elevated Microglial ECM Proteoglycan Uptake in 5xFAD Mice. [europepmc]

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