Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (C.S.-B., S.C.-A., C.L.T., L.B., A.S.K.); and Department of Biochemistry, University of Oxford, Oxford, United Kingdom (M.M., P.C.B.).
Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (C.S.-B., S.C.-A., C.L.T., L.B., A.S.K.); and Department of Biochemistry, University of Oxford, Oxford, United Kingdom (M.M., P.C.B.)
Mol Pharmacol. 2019 Dec;96(6):835-850. doi: 10.1124/mol.119.116871. Epub 2019 Oct 3.
The -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) constitute a subclass of the ionotropic glutamate receptor superfamily, which functions as glutamate-gated cation channels to mediate the majority of excitatory neurotransmission in the central nervous system. AMPARs are therapeutic targets in a range of brain disorders associated with abnormal glutamate hyperactivity. Multiple classes of AMPAR inhibitors have been developed during the past decades, including competitive antagonists, ion channel blockers, and negative allosteric modulators (NAMs). At present, the NAM is the only class of AMPAR ligands that have been developed into safe and useful drugs in humans in the form of perampanel (Fycompa), which was recently approved for treatment of epilepsy. Compared with the detailed understanding of other AMPAR ligand classes, surprisingly little information has been available regarding the molecular mechanism of perampanel and other classes of NAMs at AMPARs; including the location and structure of NAM binding pockets in the receptor complex. However, structures of the AMPAR GluA2 in complex with NAMs were recently reported that unambiguously identified the NAM binding sites. In parallel with this work, our aim with the present study was to identify specific residues involved in the formation of the NAM binding site for three prototypical AMPAR NAMs. Hence, we have performed a mutational analysis of the AMPAR region that links the four extracellular ligand-binding domains to the central ion channel in the transmembrane domain region. Furthermore, we perform computational ligand docking of the NAMs into structural models of the homomeric GluA2 receptor and optimize side chain conformations around the NAMs to model how NAMs bind in this specific site. The new insights provide potentially valuable input for structure-based drug design of new NAMs. SIGNIFICANCE STATEMENT: The -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are glutamate-gated ion channels that mediate the majority of excitatory neurotransmission in the brain. Negative allosteric modulators of AMPA receptors are considered to have significant therapeutic potential in diseases linked to glutamate hyperactivity. The present work employs mutational analysis and molecular modeling of the binding site for prototypical NAMs to provide new molecular insight into how NAMs interact with the AMPA receptor, which is of potential use for future design of new types of NAMs.
-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体（AMPARs）构成离子型谷氨酸受体超家族的一个亚类，作为谷氨酸门控阳离子通道，介导中枢神经系统中大多数兴奋性神经递质的传递。AMPARs 是与谷氨酸过度兴奋相关的一系列脑疾病的治疗靶点。在过去的几十年中，已经开发出了多种 AMPAR 抑制剂，包括竞争性拮抗剂、离子通道阻断剂和负变构调节剂（NAMs）。目前，NAM 是唯一一类已开发成人类安全有效药物的 AMPAR 配体，以吡仑帕奈（Fycompa）的形式出现，最近被批准用于治疗癫痫。与其他 AMPAR 配体类别的详细了解相比，关于吡仑帕奈和其他 NAM 类别的分子机制在 AMPAR 上的信息惊人地少；包括受体复合物中 NAM 结合口袋的位置和结构。然而，最近报道了 AMPAR GluA2 与 NAMs 复合物的结构，这些结构明确确定了 NAM 结合位点。与这项工作并行，我们目前的研究目的是确定与三种典型的 AMPAR NAMs 形成 NAM 结合位点相关的特定残基。因此，我们对连接四个细胞外配体结合域和跨膜域区域中心离子通道的 AMPAR 区域进行了突变分析。此外，我们将 NAMs 进行计算配体对接到同源 GluA2 受体的结构模型中，并优化 NAMs 周围的侧链构象，以模拟 NAMs 如何在该特定位置结合。新的见解为基于结构的新型 NAMs 药物设计提供了有价值的信息。 意义陈述：-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）受体是谷氨酸门控离子通道，介导大脑中大多数兴奋性神经递质的传递。AMPAR 的负变构调节剂被认为在与谷氨酸过度兴奋相关的疾病中有很大的治疗潜力。本工作通过对原型 NAMs 的结合位点进行突变分析和分子建模，为 NAMs 与 AMPAR 相互作用提供了新的分子见解，这对于未来新型 NAMs 的设计具有潜在的用途。
