O-GlcNAc transferase controls excitatory synapse development and AMPA receptor expression in an activity-dependent...

Area of Science:

• Neuroscience
• Cell Biology
• Metabolism

Background:

• Excitatory synapse formation and plasticity are crucial for brain development and function.
• Both neuronal activity and metabolic state influence synaptic plasticity.
• The role of the nutrient sensor O-GlcNAc transferase (OGT) in activity-dependent synaptic regulation is not well understood.

Purpose of the Study:

• To investigate how OGT regulates excitatory synapse structure, number, and AMPA-type glutamate receptors (AMPARs).
• To determine if OGT's regulation of synapses is dependent on neuronal activity.

Main Methods:

• Primary hippocampal neuron cultures at different developmental stages (DIV7 and DIV14).
• Overexpression of OGT.
• Chronic suppression of neuronal activity using tetrodotoxin (TTX).
• Immunostaining and imaging to quantify synaptic components (GluA1, PSD-95, vGluT1).

Main Results:

• OGT overexpression enhanced GluA1 accumulation in dendritic spines at mature stages (DIV14), but not early stages (DIV7).
• Activity suppression abolished OGT-dependent increase in GluA1 expression.
• OGT overexpression promoted synapse maturation, increasing postsynaptic PSD-95 and presynaptic vGluT1 puncta size and intensity.
• OGT-induced increases in synapse number and structural maturation were dependent on neuronal activity.

Conclusions:

• OGT acts as an activity-dependent regulator of excitatory synapse maturation.
• OGT influences AMPARs accumulation in a neuronal activity-dependent manner.
• This study reveals a mechanism integrating metabolic signaling and neuronal activity to shape synaptic connectivity and function.