HDAC4 governs a transcriptional program essential for synaptic plasticity and memory

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Neuronal activity shapes gene expression crucial for brain development and function.
• The molecular mechanisms linking neuronal activity to gene regulation are not fully understood.
• Histone deacetylases (HDACs) are key epigenetic regulators implicated in various cellular processes.

Purpose of the Study:

• To investigate the role of histone deacetylase 4 (HDAC4) in neuronal plasticity and memory.
• To elucidate the molecular mechanisms by which HDAC4 influences synaptic function.
• To examine the impact of a specific HDAC4 allele associated with mental retardation on brain function.

Main Methods:

• Studied HDAC4 shuttling between the nucleus and cytoplasm in response to neuronal stimulation.
• Investigated HDAC4's interaction with chromatin and its regulation by NMDA receptors.
• Analyzed the transcriptional targets of HDAC4 and their role in synaptic components.
• Utilized a mouse model carrying a mutation mimicking the mental retardation-associated allele.

Main Results:

• HDAC4 nuclear import and chromatin association are negatively regulated by NMDA receptor activity.
• Nuclear HDAC4 represses genes essential for central synapse formation and function, impacting synaptic strength.
• A truncated, gain-of-function HDAC4 repressor, associated with mental retardation, disrupts transcription and synaptic transmission.
• Mice with the mutant HDAC4 allele exhibit deficits in neurotransmission, spatial learning, and memory.

Conclusions:

• HDAC4 is a critical molecular link between neuronal activity and the regulation of synaptic plasticity and memory.
• Dysfunctional HDAC4, particularly the mutant form linked to mental retardation, leads to significant cognitive and synaptic deficits.
• These findings reveal a key mechanism of experience-dependent brain plasticity and the specific biological role of HDAC4 in cognitive functions.