Simard Jeffrey R, Michelsen Klaus, Wang Yan, Yang Chunhua, Youngblood Beth, Grubinska Barbara, Taborn Kristin, Gillie Daniel J, Cook Kevin, Chung Kyu, Long Alexander M, Hall Brian E, Shaffer Paul L, Foti Robert S, Gingras Jacinthe
Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.).
J Pharmacol Exp Ther. 2022 Oct;383(1):56-69. doi: 10.1124/jpet.121.001026. Epub 2022 Aug 4.
Ion channels are targets of considerable therapeutic interest to address a wide variety of neurologic indications, including pain perception. Current pharmacological strategies have focused mostly on small molecule approaches that can be limited by selectivity requirements within members of a channel family or superfamily. Therapeutic antibodies have been proposed, designed, and characterized to alleviate this selectivity limitation; however, there are no Food and Drug Administration-approved therapeutic antibody-based drugs targeting ion channels on the market to date. Here, in an effort to identify novel classes of engineered ion channel modulators for potential neurologic therapeutic applications, we report the generation and characterization of six (EC < 25nM) Cys-loop receptor family monoclonal antibodies with modulatory function against rat and human glycine receptor alpha 1 (GlyR1) and/or GlyR3. These antibodies have activating (i.e., positive modulator) or inhibiting (i.e., negative modulator) profiles. Moreover, GlyR3 selectivity was successfully achieved for two of the three positive modulators identified. When dosed intravenously, the antibodies achieved sufficient brain exposure to cover their calculated in vitro EC values. When compared head-to-head at identical exposures, the GlyR3-selective antibody showed a more desirable safety profile over the nonselective antibody, thus demonstrating, for the first time, an advantage for GlyR3-selectivity. Our data show that ligand-gated ion channels of the glycine receptor family within the central nervous system can be functionally modulated by engineered biologics in a dose-dependent manner and that, despite high protein homology between the alpha subunits, selectivity can be achieved within this receptor family, resulting in future therapeutic candidates with more desirable drug safety profiles. SIGNIFICANCE STATEMENT: This study presents immunization and multiplatform screening approaches to generate a diverse library of functional antibodies (agonist, potentiator, or inhibitory) raised against human glycine receptors (GlyRs). This study also demonstrates the feasibility of acquiring alpha subunit selectivity, a desirable therapeutic profile. When tested in vivo, these tool molecules demonstrated an increased safety profile in favor of GlyRα3-selectivity. These are the first reported functional GlyR antibodies that may open new avenues to treating central nervous system diseases with subunit selective biologics.
离子通道是治疗多种神经适应症（包括痛觉）的重要治疗靶点。目前的药理学策略主要集中在小分子方法上，这些方法可能受到通道家族或超家族成员内选择性要求的限制。已经提出、设计并表征了治疗性抗体以减轻这种选择性限制；然而，迄今为止，市场上还没有美国食品药品监督管理局批准的基于治疗性抗体的靶向离子通道的药物。在此，为了识别用于潜在神经治疗应用的新型工程化离子通道调节剂类别，我们报告了六种（EC<25nM）具有针对大鼠和人类甘氨酸受体α1（GlyR1）和/或GlyR3调节功能的Cys-loop受体家族单克隆抗体的产生和表征。这些抗体具有激活（即正向调节剂）或抑制（即负向调节剂）特性。此外，在所鉴定的三种正向调节剂中的两种中成功实现了对GlyR3的选择性。静脉给药时，这些抗体在脑中达到了足够的暴露量，以覆盖其计算出的体外EC值。当在相同暴露量下进行直接比较时，GlyR3选择性抗体显示出比非选择性抗体更理想的安全性，从而首次证明了GlyR3选择性的优势。我们的数据表明，中枢神经系统中甘氨酸受体家族的配体门控离子通道可以被工程化生物制剂以剂量依赖的方式进行功能调节，并且尽管α亚基之间具有高度的蛋白质同源性，但仍可在该受体家族内实现选择性，从而产生具有更理想药物安全性概况的未来治疗候选物。意义声明：本研究提出了免疫和多平台筛选方法，以生成针对人类甘氨酸受体（GlyRs）的多种功能性抗体（激动剂、增强剂或抑制剂）文库。本研究还证明了获得α亚基选择性（一种理想的治疗特性）的可行性。在体内测试时，这些工具分子显示出有利于GlyRα3选择性的更高安全性。这些是首次报道的功能性GlyR抗体，可能为用亚基选择性生物制剂治疗中枢神经系统疾病开辟新途径。
