Analogs of α-conotoxin PnIC selectively inhibit α7β2- over α7-only subtype nicotinic acetylcholine receptors via a novel allosteric mechanism.
Analogs of α-conotoxin PnIC selectively inhibit α7β2- over α7-only subtype nicotinic acetylcholine receptors via a novel allosteric mechanism.
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DOI：
10.1096/fj.202302079
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发表时间：
2024-01
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本研究旨在鉴定和鉴定第一批能够选择性识别含有α7和β2亚基的烟碱型乙酰胆碱受体的配体(α7β2-nAChR亚型)。基底前脑胆碱能神经元表达α-7、β-2-nAChR。在这里，它们似乎介导了由与早期阿尔茨海默病相关的寡聚淀粉样蛋白-β水平升高引起的神经元功能障碍。其他研究表明，α7、β2-nAChR在中枢神经系统内的几个更重要的胆碱能和GABA能神经元回路中都有表达。然而，由于目前可用的配体不能区分异构体α7β2-nAChR和密切相关且分布更广泛的同源α7-Only-nAChR亚型，进一步的研究受到了显著阻碍。通过双电极电压钳电生理功能筛选，鉴定出一类α7β2-nAChR选择性α-conooxPnIC类似物(α-CTxPnIC)。使用电生理学、功能动力学、定点突变和分子动力学相结合的方法进一步表征了这些α-β类似物的α-CtxPnIC的选择性和作用位点。我们确定α7β2-nAChR的α-CtxPnIC类似物的选择性来自于与α7β2-和α7-Only-nAChR共享的正位立位激动剂结合位点的相互作用。由于许多先前发现的α-CTX配体是正构体激动剂结合位点的竞争性拮抗剂，本研究深刻地扩大了α-CTX配体的使用范围(它已经提供了重要的nAChR研究和翻译突破)。更直接的是，α-CtxPnIC的类似物有望首次实现对α7β2-nAChR分布的全面定位和对其生理作用的详细研究。α-芋螺毒素PnIC的类似物通过一种新的变构机制选择性地抑制α7-β2-在α7-唯一亚型烟碱乙酰胆碱受体上。Andrew A.George，Sabin J.John，Linda M.Lucero，J.Brek Eaton，Ekta Jaiswal，Sean B.Christensen，Joanna Gajewiak，Maren Watkins，Iwei曹，Baldomero M.Olivera，Wonpil Im，J.Michael McIntosh和Paul Whiteaker*我们描述了含有α-Conooxin PnIC(α-CtxPnIC)对含有α7和β2亚单位的尼古丁受体(α7β2-nAChR)具有选择性。到目前为止，几乎不可能与广泛分布的α7-nAChR区分开来，α7β2-nAChR似乎在多个神经元群体中发挥着重要的生理作用。与前面描述的竞争激动剂结合位点的α-Ctxs不同，α-CtxPnIC类似物通过一种新的变构机制获得α7β2-nAChR选择性(如上所示)。这一发现从根本上扩大了α-CTX的研究范围，并使首次全面研究α7β2-nAChR的分布和作用成为可能。
This study was undertaken to identify and characterize the first ligands capable of selectively identifying nicotinic acetylcholine receptors containing α7 and β2 subunits (α7β2‐nAChR subtype). Basal forebrain cholinergic neurons express α7β2‐nAChR. Here, they appear to mediate neuronal dysfunction induced by the elevated levels of oligomeric amyloid‐β associated with early Alzheimer's disease. Additional work indicates that α7β2‐nAChR are expressed across several further critically important cholinergic and GABAergic neuronal circuits within the central nervous system. Further studies, however, are significantly hindered by the inability of currently available ligands to distinguish heteromeric α7β2‐nAChR from the closely related and more widespread homomeric α7‐only‐nAChR subtype. Functional screening using two‐electrode voltage‐clamp electrophysiology identified a family of α7β2‐nAChR‐selective analogs of α‐conotoxin PnIC (α‐CtxPnIC). A combined electrophysiology, functional kinetics, site‐directed mutagenesis, and molecular dynamics approach was used to further characterize the α7β2‐nAChR selectivity and site of action of these α‐CtxPnIC analogs. We determined that α7β2‐nAChR selectivity of α‐CtxPnIC analogs arises from interactions at a site distinct from the orthosteric agonist‐binding site shared between α7β2‐ and α7‐only‐nAChR. As numerous previously identified α‐Ctx ligands are competitive antagonists of orthosteric agonist‐binding sites, this study profoundly expands the scope of use of α‐Ctx ligands (which have already provided important nAChR research and translational breakthroughs). More immediately, analogs of α‐CtxPnIC promise to enable, for the first time, both comprehensive mapping of the distribution of α7β2‐nAChR and detailed investigations of their physiological roles. Analogs of α‐conotoxin PnIC selectively inhibit α7β2‐ over α7‐only subtype nicotinic acetylcholine receptors via a novel allosteric mechanism.Andrew A. George, Sabin J. John, Linda M. Lucero, J. Brek Eaton, Ekta Jaiswal, Sean B. Christensen, Joanna Gajewiak, Maren Watkins, Yiwei Cao, Baldomero M. Olivera, Wonpil Im, J. Michael McIntosh, & Paul Whiteaker*We describe α‐conotoxin PnIC (α‐CtxPnIC) analogs with selectivity towards nicotinic acetylcholine receptors containing α7 and β2 subunits (α7β2‐nAChR). Until now almost impossible to distinguish from widely‐distributed α7‐only‐nAChR, α7β2‐nAChR appear to play important physiological roles in multiple neuronal populations. Unlike previously‐described α‐Ctxs that compete for agonist binding sites, α‐CtxPnIC analogs gain α7β2‐nAChR selectivity via a novel allosteric mechanism (illustrated above). This finding fundamentally expands the scope of α‐Ctx studies, and enables the first comprehensive studies of α7β2‐nAChR distribution and roles.
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影响因子：
7.3
作者：
Bavo, Francesco;Pallavicini, Marco;Pucci, Susanna;Appiani, Rebecca;Giraudo, Alessandro;Eaton, Brek;Lucero, Linda;Gotti, Cecilia;Moretti, Milena;Whiteaker, Paul;Bolchi, Cristiano
通讯作者：
Bolchi, Cristiano
影响因子：
16.2
作者：
Gu, Shenyan;Matta, Jose A.;Bredt, David S.
通讯作者：
Bredt, David S.
影响因子：
8.2
作者：
Azam, Layla;McIntosh, J. Michael
通讯作者：
McIntosh, J. Michael
影响因子：
4.4
作者：
ESSMANN, U;PERERA, L;PEDERSEN, LG
通讯作者：
PEDERSEN, LG
影响因子：
4.3
作者：
Eastman P;Swails J;Chodera JD;McGibbon RT;Zhao Y;Beauchamp KA;Wang LP;Simmonett AC;Harrigan MP;Stern CD;Wiewiora RP;Brooks BR;Pande VS
通讯作者：
Pande VS