Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov St. 32, 119991 Moscow, Russia.
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, Russia.
Int J Mol Sci. 2020 Aug 29;21(17):6272. doi: 10.3390/ijms21176272.
The cholinergic deficit in Alzheimer's disease (AD) may arise from selective loss of cholinergic neurons caused by the binding of Aβ peptide to nicotinic acetylcholine receptors (nAChRs). Thus, compounds preventing such an interaction are needed to address the cholinergic dysfunction. Recent findings suggest that the EVHH site in Aβ peptide mediates its interaction with α4β2 nAChR. This site contains several charged amino acid residues, hence we hypothesized that the formation of Aβ-α4β2 nAChR complex is based on the interaction of EVHH with its charge-complementary counterpart in α4β2 nAChR. Indeed, we discovered a HAEE site in α4β2 nAChR, which is charge-complementary to EVHH, and molecular modeling showed that a stable Aβ-α4β2 nAChR complex could be formed via the EVHH:HAEE interface. Using surface plasmon resonance and bioinformatics approaches, we further showed that a corresponding tetrapeptide Ac-HAEE-NH can bind to Aβ via EVHH site. Finally, using two-electrode voltage clamp in oocytes, we showed that Ac-HAEE-NH tetrapeptide completely abolishes the Aβ-induced inhibition of α4β2 nAChR. Thus, we suggest that HAEE is a potential binding site for Aβ on α4β2 nAChR and Ac-HAEE-NH tetrapeptide corresponding to this site is a potential therapeutic for the treatment of α4β2 nAChR-dependent cholinergic dysfunction in AD.
阿尔茨海默病(AD)中的胆碱能缺陷可能源于胆碱能神经元的选择性丧失,这是由 Aβ 肽与烟碱型乙酰胆碱受体(nAChRs)结合引起的。因此,需要能够阻止这种相互作用的化合物来解决胆碱能功能障碍问题。最近的研究结果表明,Aβ 肽中的 EVHH 位点介导了其与 α4β2 nAChR 的相互作用。该位点包含几个带电荷的氨基酸残基,因此我们假设 Aβ-α4β2 nAChR 复合物的形成是基于 EVHH 与 α4β2 nAChR 中带电荷互补的对应物的相互作用。事实上,我们在 α4β2 nAChR 中发现了一个 HAEE 位点,它与 EVHH 带电荷互补,分子建模表明,通过 EVHH:HAEE 界面可以形成稳定的 Aβ-α4β2 nAChR 复合物。使用表面等离子体共振和生物信息学方法,我们进一步表明,相应的四肽 Ac-HAEE-NH 可以通过 EVHH 位点与 Aβ 结合。最后,我们在卵母细胞中使用双电极电压钳技术表明,Ac-HAEE-NH 四肽完全消除了 Aβ 诱导的 α4β2 nAChR 抑制。因此,我们认为 HAEE 是 Aβ 与 α4β2 nAChR 结合的潜在结合位点,而对应于该位点的 Ac-HAEE-NH 四肽是治疗 AD 中 α4β2 nAChR 依赖性胆碱能功能障碍的潜在治疗药物。