Dopamine-regulated microRNA MiR-181a controls GluA2 surface expression in hippocampal neurons

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Synaptic plasticity is crucial for learning and memory, and is altered by drug addiction.
• MicroRNAs (miRNAs) are emerging regulators of gene expression, but their role in synaptic plasticity and drug neuroadaptation is unclear.
• AMPA-type glutamate receptors (AMPA-R) are key mediators of synaptic plasticity.

Purpose of the Study:

• To identify miRNAs regulating synaptic plasticity in the nucleus accumbens.
• To investigate if miRNAs target glutamate receptors to mediate synaptic plasticity.
• To explore the role of miR-181a in regulating AMPA-R and its implications in drug-induced plasticity.

Main Methods:

• Microarray screening to identify miRNAs.
• Bioinformatic analysis to predict miRNA binding sites.
• Overexpression and knockdown experiments in primary neurons.
• Electrophysiology and imaging in hippocampal neurons.
• Drug treatment in a mouse model.

Main Results:

• miR-181a was identified as a miRNA enriched at medium spiny neuron synapses.
• miR-181a directly targets the mRNA of the GluA2 subunit of AMPA-Rs.
• miR-181a negatively regulates GluA2 expression and reduces GluA2 surface expression.
• miR-181a overexpression decreased spine formation and mEPSC frequency.
• miR-181a expression is induced by dopamine signaling and chronic exposure to cocaine and amphetamines.

Conclusions:

• miR-181a is a key posttranscriptional regulator of mammalian AMPA-type glutamate receptors.
• miR-181a plays a significant role in synaptic plasticity.
• miR-181a may mediate drug-induced synaptic plasticity and neuroadaptations to drugs of abuse.