Muscarinic Receptors as Model Targets and Antitargets for Structure-Based Ligand Discovery
Muscarinic Receptors as Model Targets and Antitargets for Structure-Based Ligand Discovery
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DOI：
10.1124/mol.113.087551
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发表时间：
2013-10-01
影响因子：
3.6
通讯作者：
Shoichet, Brian K.
中科院分区：
文献类型：
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作者：
Kruse, Andrew C.;Weiss, Dahlia R.;Shoichet, Brian K.
G蛋白偶联受体(GPCRs)实际上调节着人体生理的各个方面，是一类重要的治疗药物靶点。许多GPCR靶向药物类似于内源性激动剂，往往导致受体亚型的选择性较差，药理图谱受限。M碱乙酰胆碱受体家族就是这些问题的例证；已知的配体有数千种，但很少有受体亚型选择性的，而且几乎所有的配体本质上都是阳离子的。利用与M-2和M-3受体的基于结构的对接，我们筛选了310万个分子，寻找具有新的物理性质、化学类型和受体亚型选择性的配体。在针对M-2亚型测试的19个对接优先的分子中，11个具有实质性的活性，8个代表新的化学类型。有趣的是，有两个是低微摩尔到高纳摩尔K-I值的不带电荷的配体，这在胺能GPCRs中几乎没有先例。为了利用M-2和M-3受体之间的结合口袋中的单个氨基酸替代，我们选择了通过对接预测的分子与M-3结合，但不与M-2受体结合。在测试的16个分子中，有8个与M-3受体结合。虽然大多数药物的选择性仍然不高，但其中一种是M-3受体的部分激动剂，没有可测量的M-2激动剂。与这种活性一致的是，这种化合物刺激了小鼠β细胞系的胰岛素释放。这些结果支持了基于结构的发现发现具有未知化学类型和物理性质的新配体的能力，从而导致新的生物功能，即使在毒扁豆碱药理这样一个广泛探索的领域也是如此。
G protein-coupled receptors (GPCRs) regulate virtually all aspects of human physiology and represent an important class of therapeutic drug targets. Many GPCR-targeted drugs resemble endogenous agonists, often resulting in poor selectivity among receptor subtypes and restricted pharmacologic profiles. The muscarinic acetylcholine receptor family exemplifies these problems; thousands of ligands are known, but few are receptor subtype-selective and nearly all are cationic in nature. Using structure-based docking against the M-2 and M-3 muscarinic receptors, we screened 3.1 million molecules for ligands with new physical properties, chemotypes, and receptor subtype selectivities. Of 19 docking-prioritized molecules tested against the M-2 subtype, 11 had substantial activity and 8 represented new chemotypes. Intriguingly, two were uncharged ligands with low micromolar to high nanomolar K-i values, an observation with few precedents among aminergic GPCRs. To exploit a single amino-acid substitution among the binding pockets between the M-2 and M-3 receptors, we selected molecules predicted by docking to bind to the M-3 and but not the M-2 receptor. Of 16 molecules tested, 8 bound to the M-3 receptor. Whereas selectivity remained modest for most of these, one was a partial agonist at the M-3 receptor without measurable M-2 agonism. Consistent with this activity, this compound stimulated insulin release from a mouse beta-cell line. These results support the ability of structure-based discovery to identify new ligands with unexplored chemotypes and physical properties, leading to new biologic functions, even in an area as heavily explored as muscarinic pharmacology.