Beta Amyloid Peptide: Research Paper : Selective co-activation of α7- and α4β2-nicotinic acetylcholine receptors reverses beta-amyloid-induced synaptic dysfunction

Selective co-activation of α7- and α4β2-nicotinic acetylcholine receptors reverses beta-amyloid-induced synaptic dysfunction

Abstract

Beta-amyloid (Aβ) has been recognized as an early trigger in the pathogenesis of Alzheimer's disease (AD) leading to synaptic and cognitive impairments. Aβ can alter neuronal signaling through interactions with nicotinic acetylcholine receptors (nAChRs), contributing to synaptic dysfunction in AD. The three major nAChR subtypes in the hippocampus are composed of α7-, α4β2-, and α3β4-nAChRs. Aβ selectively affects α7- and α4β2-nAChRs, but not α3β4-nAChRs in hippocampal neurons, resulting in neuronal hyperexcitation. However, how nAChR subtype selectivity for Aβ affects synaptic function in AD is not completely understood. Here, we showed that Aβ associated with α7- and α4β2-nAChRs but not α3β4-nAChRs. Computational modeling suggested two amino acids in α7-nAChRs, arginine 208 and glutamate 211, were important for the interaction between Aβ and α7-containing nAChRs. These residues are conserved only in the α7 and α4 subunits. We therefore mutated these amino acids in α7-containing nAChRs to mimic the α3 subunit and found that mutant α7-containing receptors were unable to interact with Aβ. Additionally, mutant α3-containing nAChRs mimicking the α7 subunit interact with Aβ. This provides direct molecular evidence for how Aβ selectively interacted with α7- and α4β2-nAChRs, but not α3β4-nAChRs. Selective co-activation of α7- and α4β2-nAChRs also sufficiently reversed Aβ-induced AMPA receptor (AMPAR) dysfunction, including Aβ-induced reduction of AMPAR phosphorylation and surface expression in hippocampal neurons. Moreover, co-stimulation of α7- and α4β2-nAChRs reversed the Aβ-induced disruption of long-term potentiation. These findings support a novel mechanism for Aβ's impact on synaptic function in AD, namely the differential regulation of nAChR subtypes.

Keywords: AMPAR); Alzheimer disease; alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA receptor; amyloid-beta (Aβ); nicotinic acetylcholine receptors (nAChR); synaptic plasticity.

This article originally appeared in the "https://pubmed.ncbi.nlm.nih.gov/33571523/" and has their copyrights. We do not claim copyright on the content. This information is for research purposes only. This Blog is made available by publishers for educational purposes only as well as to give you general information and a general understanding , not to provide specific advice. By using this blog site you understand that there is no client relationship between you and the Blog publisher. The Blog should not be used as a substitute for competent research advice.