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Updated: Aug 20, 2025
Analysis of Dendritic Spine Morphology in Cultured CNS Neurons
Published on: July 13, 2011
Microglial WNT5A supports dendritic spines maturation and neuronal firing
Hana Yeh1, Maya E Woodbury1, Kaitlin L Ingraham Dixie2
1Graduate Program in Neuroscience, Boston University, United States; Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States.
Abstract:
There is increasing evidence showing that microglia play a critical role in mediating synapse formation and spine growth, although the molecular mechanism remains elusive. Here, we demonstrate that the secreted morphogen WNT family member 5A (WNT5A) is the most abundant WNT expressed in microglia and that it promotes neuronal maturation. Co-culture of microglia with Thy1-YFP+ differentiated neurons significantly increased neuronal spine density and reduced dendritic spine turnover rate, which was diminished by silencing microglial Wnt5a in vitro. Co-cultured microglia increased post-synaptic marker PSD95 and synaptic density as determined by the co-localization of PSD95 with pre-synaptic marker VGLUT2 in vitro. The silencing of Wnt5a expression in microglia partially reduced both PSD95 and synaptic densities. Co-culture of differentiated neurons with microglia significantly enhanced neuronal firing rate as measured by multiple electrode array, which was significantly reduced by silencing microglial Wnt5a at 23 days differentiation in vitro. These findings demonstrate that microglia can mediate spine maturation and regulate neuronal excitability via WNT5A secretion indicating possible pathological roles of dysfunctional microglia in developmental disorders.
Insights
Microglia promote neuronal maturation and synapse development by secreting WNT family member 5A (WNT5A). This mechanism highlights microglia's role in brain development and potential links to developmental disorders.
Area of Science:
- Neuroscience
- Cell Biology
- Developmental Biology
Background:
- Microglia are increasingly recognized for their role in synapse formation and neuronal development.
- The precise molecular mechanisms underlying microglial influence on synaptic plasticity remain largely unknown.
Purpose of the Study:
- To investigate the role of WNT family member 5A (WNT5A) secreted by microglia in promoting neuronal maturation and synapse formation.
- To elucidate the molecular pathways through which microglia modulate neuronal excitability.
Main Methods:
- Quantification of WNT5A expression in microglia.
- In vitro co-culture systems of microglia and differentiated neurons.
- Silencing of Wnt5a expression in microglia using in vitro techniques.
- Assessment of neuronal spine density, dendritic spine turnover, and synaptic marker expression (PSD95, VGLUT2).
- Measurement of neuronal firing rates using multiple electrode arrays.
Main Results:
- WNT5A was identified as the most abundant WNT ligand secreted by microglia.
- Microglial co-culture significantly increased neuronal spine density and reduced spine turnover, effects dependent on WNT5A.
- Synaptic density and post-synaptic marker PSD95 levels were elevated in co-cultured neurons, with WNT5A-dependent contributions.
- Neuronal firing rates were enhanced by microglial co-culture, an effect reduced by Wnt5a silencing.
Conclusions:
- Microglia regulate neuronal maturation and synaptic plasticity through the secretion of WNT5A.
- Dysfunctional microglia and altered WNT5A signaling may contribute to the pathophysiology of developmental disorders.
- This study identifies a novel molecular mechanism linking microglia to neuronal development and function.
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