Long-term Locus Coeruleus Stimulation Exacerbates Tau Pathology in PS19 Mice

Area of Science:

• Neuroscience
• Neurobiology
• Pathology

Background:

• Alzheimer's disease (AD) is a neurodegenerative disorder characterized by amyloid-β plaques and Tau tangles.
• The locus coeruleus (LC) is an early site of degeneration and Tau pathology in AD.
• Previous research shows mixed effects of norepinephrine modulation on memory in AD models.

Purpose of the Study:

• To investigate the impact of long-term LC stimulation on memory, synaptic plasticity, and tauopathy in PS19 mice.
• To assess behavioral, electrophysiological, and immunohistochemical changes following chronic LC stimulation.

Main Methods:

• PS19 mice underwent long-term LC stimulation.
• Memory was assessed using the radial arm water maze and fear conditioning.
• Synaptic plasticity was measured via hippocampal long-term potentiation (LTP).
• Tau phosphorylation, neurodegeneration, and neuroinflammation were analyzed using immunohistochemistry.

Main Results:

• Long-term LC stimulation worsened spatial and contextual memory in PS19 mice.
• Hippocampal LTP was reduced, indicating impaired synaptic plasticity.
• Increased Tau hyperphosphorylation, AEP expression, and astrocyte activation were observed.

Conclusions:

• Long-term LC stimulation exacerbates memory deficits and synaptic impairment in PS19 mice.
• This exacerbation may be linked to increased Tau pathology and neuroinflammation.
• Norepinephrine elevation from LC stimulation could contribute to Tau hyperphosphorylation.