Positive allosteric activation of glial EAAT-2 transporter protein: A novel strategy for Alzheimer's disease

Excitatory amino acid transporter-2 (EAAT-2) protein localized in the membrane of glial cells are responsible for the clearance of glutamate in synapse and it plays a key role among the five glutamate transporters (EAATs) in regulating synaptic transmission and preventing excitotoxicity in neurons. EAAT-2 dysfunction has been associated with the neuropathology of Alzheimer's disease (AD). Impairment of EAAT-2 transporter function results excess accumulation of glutamate in synaptic cleft that acts on post-synaptic glutaminergic receptors excessively resulting in influx of Na+ and Ca2+ ions into the neurons. This triggers excitotoxicity in post-synaptic neurons by activating apoptotic or necrotic pathways causing neurodegeneration in AD. The compounds that increase the EAAT-2 activity may have therapeutic potential for neuroprotection in AD. The positive allosteric site activation of EAAT-2 represents a promising entry point for the identification of novel pharmacological compounds for the management of neurodegenerative conditions involving glutamate-mediated excitotoxicity. We hypothesize, therefore, that the positive allosteric activators may enhance glutamate clearance from the synaptic cleft by promoting orthosteric binding of glutamate ligand in EAAT-2 transporter protein and attenuate the excitotoxicity in neurons and prevent the disease progression of AD.