Prefrontal Cortical GABAergic Dysfunction Contributes to Aberrant UP-State Duration in APP Knockout Mice

Area of Science:

• Neuroscience
• Molecular Biology
• Systems Biology

Background:

• Amyloid beta protein's role in Alzheimer's pathogenesis is well-studied.
• Physiological functions of its precursor, amyloid precursor protein (APP), in neural activity remain less understood.
• UP states, crucial for cortical synaptic integration during slow-wave sleep, are key indicators of network function.

Purpose of the Study:

• To investigate the physiological role of APP in regulating synaptic and network activity.
• To explore the impact of APP absence on prefrontal cortex (PFC) network function, specifically UP state duration.
• To identify potential therapeutic targets for aberrant neural network activity.

Main Methods:

• Utilized an APP knockout (APP-/-) mouse model.
• Measured UP state duration in the prefrontal cortex (PFC).
• Assessed glutamine synthetase, tissue GABA content, and GABAB receptor (GABABR) expression.
• Employed pharmacological interventions targeting GABA signaling (GABA uptake inhibitor, GABABR agonist).

Main Results:

• APP absence significantly increased UP state duration in the PFC.
• This was associated with reduced glutamine synthetase and GABA content, and increased GABABR expression.
• Pharmacological enhancement of GABA signaling normalized UP-state duration and, in some cases, GABABR expression.

Conclusions:

• APP plays a critical role in regulating PFC network function and synaptic integration.
• The GABA signaling pathway, particularly GABABRs, is implicated in APP-dependent network regulation.
• Targeting the GABAergic system offers a potential therapeutic strategy for correcting aberrant neural network activity.