Amyloid Beta-Related Alterations to Glutamate Signaling Dynamics During Alzheimer's Disease Progression

Alzheimer's disease (AD) ranks sixth on the Centers for Disease Control and Prevention Top 10 Leading Causes of Death list for 2016, and the Alzheimer's Association attributes 60% to 80% of dementia cases as AD related. AD pathology hallmarks include accumulation of senile plaques and neurofibrillary tangles; however, evidence supports that soluble amyloid beta (A beta), rather than insoluble plaques, may instigate synaptic failure. Soluble A beta accumulation results in depression of long-term potentiation leading to cognitive deficits commonly characterized in AD. The mechanisms through which A beta incites cognitive decline have been extensively explored, with a growing body of evidence pointing to modulation of the glutamatergic system. The period of glutamatergic hypoactivation observed alongside long-term potentiation depression and cognitive deficits in later disease stages may be the consequence of a preceding period of increased glutamatergic activity. This review will explore the A beta-related changes to the tripartite glutamate synapse resulting in altered cell signaling throughout disease progression, ultimately culminating in oxidative stress, synaptic dysfunction, and neuronal loss.