α-Conotoxin PeIA[S9H,V10A,E14N] Potently and Selectively Blocks α6β2β3 versus α6β4 Nicotinic Acetylcholine Receptors
α-Conotoxin PeIA[S9H,V10A,E14N] Potently and Selectively Blocks α6β2β3 versus α6β4 Nicotinic Acetylcholine Receptors
复制标题
DOI：
10.1124/mol.112.080853
复制
发表时间：
2012-11-01
影响因子：
3.6
通讯作者：
McIntosh, J. Michael
中科院分区：
文献类型：
--
作者：
Hone, Arik J.;Scadden, Mick'l;McIntosh, J. Michael
含有 α 6 和 β 2 亚基的烟碱乙酰胆碱受体 (nAChR) 可调节基底神经节中的多巴胺释放，是治疗神经和精神疾病（包括帕金森病和尼古丁依赖）的相关靶点。然而，β 2 和 β 4 亚基的表达谱在多种组织中重叠，包括蓝斑、视网膜、海马、背根神经节和肾上腺嗜铬细胞。结合 α 6 β 2 nAChR 的配体也能有效结合密切相关的 α 6 β 4 亚型。为了区分这两种亚型，我们合成了最近描述的 α-芋螺毒素 PeIA 的新型类似物。 PeIA 是一种肽拮抗剂，可阻断多种 nAChR 亚型，包括 alpha 6/alpha 3 beta 2 beta 3 和 alpha 6/alpha 3 beta 4 nAChR，具有低纳摩尔效力。我们系统地突变了 PeIA，并评估了所得类似物对爪蟾卵母细胞中表达的 α 6/α 3 β 2 β 3 nAChR 的增强效力和/或选择性（α 6/α 3 是包含 α 6 亚基 N 端配体结合结构域的亚基嵌合体）。根据这些结果，合成了第二代类似物。最终的类似物 PeIA[S9H,V10A,E14N] 能有效阻断 α 6/α 3 beta 2 beta 3 和 alpha 6/alpha 3 beta 4 nAChR 介导的乙酰胆碱门控电流，IC50 值分别为 223 pM 和 65 nM，两种亚型之间的分离度大于 290 倍。配体与 α 6/α 3 β 2 β 3 nAChR 结合的动力学研究得出 k(off) 为 0.096 +/- 0.001 min(-1)，k on 为 0.23 +/- 0.019 min(-1) M-9。 PeIA[S9H,V10A,E14N] 的合成表明，可以开发配体来区分 α 6 β 2 和 α 6 β 4 nAChR。
Nicotinic acetylcholine receptors (nAChRs) containing alpha 6 and beta 2 subunits modulate dopamine release in the basal ganglia and are therapeutically relevant targets for treatment of neurological and psychiatric disorders including Parkinson's disease and nicotine dependence. However, the expression profile of beta 2 and beta 4 subunits overlap in a variety of tissues including locus ceruleus, retina, hippocampus, dorsal root ganglia, and adrenal chromaffin cells. Ligands that bind alpha 6 beta 2 nAChRs also potently bind the closely related alpha 6 beta 4 subtype. To distinguish between these two subtypes, we synthesized novel analogs of a recently described alpha-conotoxin, PeIA. PeIA is a peptide antagonist that blocks several nAChR subtypes, including alpha 6/alpha 3 beta 2 beta 3 and alpha 6/alpha 3 beta 4 nAChRs, with low nanomolar potency. We systematically mutated PeIA and evaluated the resulting analogs for enhanced potency and/or selectivity for alpha 6/alpha 3 beta 2 beta 3 nAChRs expressed in Xenopus oocytes (alpha 6/alpha 3 is a subunit chimera that contains the N-terminal ligand-binding domain of the alpha 6 subunit). On the basis of these results, second-generation analogs were then synthesized. The final analog, PeIA[S9H,V10A,E14N], potently blocked acetylcholine-gated currents mediated by alpha 6/alpha 3 beta 2 beta 3 and alpha 6/alpha 3 beta 4 nAChRs with IC50 values of 223 pM and 65 nM, respectively, yielding a >290-fold separation between the two subtypes. Kinetic studies of ligand binding to alpha 6/alpha 3 beta 2 beta 3 nAChRs yielded a k(off) of 0.096 +/- 0.001 min(-1) and a k on of 0.23 +/- 0.019 min(-1) M-9. The synthesis of PeIA[S9H,V10A,E14N] demonstrates that ligands can be developed to discriminate between alpha 6 beta 2 and alpha 6 beta 4 nAChRs.