Identification of α4β2 nAChR interaction site with Aβ42 and development of tetrapeptide capable of breaking this interaction

Abstract

AbstractBackgroundCholinergic dysfunction in Alzheimer’s disease may arise from selective death of cholinergic neurons caused by the interaction of Aβ peptide with nicotinic acetylcholine receptors (nAChRs). Thereby, compounds that prevent the interaction of Aβ with nAChRs are needed to address the cholinergic deficit. Here, we identify the interaction site between Aβ42 and one of the two most abundant nicotinic receptors ‐ α4β2 nAChR. Further, we propose a tetrapeptide that prevents this interaction and serves as a potential therapeutic to counteract the cholinergic deficit in AD.MethodSequence analysis was used to identify the binding site of Aβ42 to α4β2 nAChR (35HAEE38). Surface plasmon resonance was utilized to evaluate the interaction between HAEE peptide and Aβ16. A complex of human α4β2 nAChR with Aβ42 was modeled with bioinformatics approaches. Human α4β2 nAChR was expressed in X. laevis oocytes. The receptor currents in the presence of Aβ42 and HAEE were studied with a two‐electrode voltage clamp.ResultAnalysis of α4β2 nAChR sequence showed that N‐terminal fragment 35HAEE38 of the α4 subunit is ionic complementary to 11EVHH14 in Aβ, suggesting it to be a potential site of the interaction. Synthetic HAEE peptide demonstrated binding to Aβ16, and molecular modeling confirmed that interaction of Aβ42 with α4β2 nAChR can occur via 11EVHH14:35HAEE38 interface. Pre‐incubation with Aβ42 reduced the amplitude of ACh‐evoked response in α4β2 nAChR‐transfected X. laevis oocytes by 20% and increased the leakage current in oocytes. Co‐incubation of Aβ42 with HAEE tetrapeptide reduced the degree of inhibition. Washout of Aβ42 with HAEE‐containing solution restored the current amplitude and reduced the leakage current.Conclusion35HAEE38 is a potential binding site for Aβ42 on α4β2 nAChR. HAEE tetrapeptide corresponding to this site restores inhibition of α4β2 nAChR by Aβ42 opening a potential therapeutic avenue for cholinergic dysfunction in AD.Supported by RSF grant #19‐74‐30007.