Chemogenetic neuronal silencing decouples c-Jun activation from cell death in the temporal cortex

Area of Science:

• Neuroscience
• Molecular Biology
• Neurodegeneration

Background:

• Early Alzheimer's disease (AD) involves diminished activity in vulnerable temporal lobe circuits before cell death.
• Neuronal activity disruption may causally contribute to regional vulnerability in neurodegenerative disorders.
• Previous work suggested entorhinal neuron death follows electrical activity suppression.

Purpose of the Study:

• To investigate the role of c-Jun activation in neurodegeneration following entorhinal cortex silencing.
• To explore alternative mechanisms driving neurodegeneration in response to neuronal activity loss.

Main Methods:

• Electrical silencing of entorhinal cortex circuits in vivo.
• Analysis of transcriptional changes and c-Jun activation.
• Pharmacological inhibition of c-Jun.
• Assessment of neuronal degeneration.
• Investigation of integrated stress response pathways.

Main Results:

• Electrical arrest of entorhinal circuits induced c-Jun activation and associated transcriptional changes.
• These gene expression patterns resemble those in other AD-vulnerable neuronal populations.
• Inhibition of c-Jun did not prevent neurodegeneration after activity disruption.
• Preliminary evidence suggests the integrated stress response may be involved in entorhinal degeneration.

Conclusions:

• c-Jun is activated by neuronal silencing in the entorhinal cortex but is decoupled from subsequent neurodegeneration.
• The c-Jun pathway is not the primary driver of degeneration in this model.
• The integrated stress response presents a potential alternative mechanism for activity-disruption-induced neurodegeneration in AD.