Dynamic DNA methylation regulates neuronal intrinsic membrane excitability

Area of Science:

• Neuroscience
• Epigenetics
• Molecular Biology

Background:

• DNA cytosine methylation is crucial for learning and memory, regulating gene expression and neuronal plasticity.
• Neuronal plasticity involves synaptic changes and alterations in intrinsic membrane excitability, affecting action potential generation.

Purpose of the Study:

• To investigate the role of DNA methyltransferase (DNMT) activity in regulating neuronal intrinsic membrane excitability.
• To elucidate the epigenetic mechanisms, including DNA demethylation and transcription, underlying changes in neuronal excitability.

Main Methods:

• Inhibition of DNA methyltransferase (DNMT) activity in cultured cortical pyramidal neurons.
• Knockdown of TET1 (cytosine demethylase) and inhibition of RNA polymerase.
• Measurement of intrinsic membrane excitability and after-hyperpolarization potential.
• Analysis of small-conductance Ca(2+)-activated K(+) (SK) channel gene expression and function.

Main Results:

• Prolonged DNMT inhibition increased neuronal intrinsic membrane excitability.
• This effect was dependent on cytosine demethylation and de novo transcription.
• DNMT inhibition reduced the medium after-hyperpolarization potential and decreased SK channel gene expression and activity.

Conclusions:

• Dynamic DNA cytosine methylation regulates neuronal intrinsic membrane excitability through transcriptional control of SK channels.
• Epigenetic modifications by DNMTs are essential for maintaining normal neuronal function.
• Dysregulated intrinsic excitability due to altered DNA methylation may contribute to neurological and psychiatric disorders.