Moutal Aubin, Chew Lindsey A, Yang Xiaofang, Wang Yue, Yeon Seul Ki, Telemi Edwin, Meroueh Seeneen, Park Ki Duk, Shrinivasan Raghuraman, Gilbraith Kerry B, Qu Chaoling, Xie Jennifer Y, Patwardhan Amol, Vanderah Todd W, Khanna May, Porreca Frank, Khanna Rajesh
Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, USA.
Department of Biological Chemistry, University of Science and Technology and Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology, Seoul, Republic of Korea.
Pain. 2016 Jul;157(7):1448-1463. doi: 10.1097/j.pain.0000000000000555.
Chronic pain affects the life of millions of people. Current treatments have deleterious side effects. We have advanced a strategy for targeting protein interactions which regulate the N-type voltage-gated calcium (CaV2.2) channel as an alternative to direct channel block. Peptides uncoupling CaV2.2 interactions with the axonal collapsin response mediator protein 2 (CRMP2) were antinociceptive without effects on memory, depression, and reward/addiction. A search for small molecules that could recapitulate uncoupling of the CaV2.2-CRMP2 interaction identified (S)-lacosamide [(S)-LCM], the inactive enantiomer of the Food and Drug Administration-approved antiepileptic drug (R)-lacosamide [(R)-LCM, Vimpat]. We show that (S)-LCM, but not (R)-LCM, inhibits CRMP2 phosphorylation by cyclin dependent kinase 5, a step necessary for driving CaV2.2 activity, in sensory neurons. (S)-lacosamide inhibited depolarization-induced Ca influx with a low micromolar IC50. Voltage-clamp electrophysiology experiments demonstrated a commensurate reduction in Ca currents in sensory neurons after an acute application of (S)-LCM. Using constellation pharmacology, a recently described high content phenotypic screening platform for functional fingerprinting of neurons that uses subtype-selective pharmacological agents to elucidate cell-specific combinations (constellations) of key signaling proteins that define specific cell types, we investigated if (S)-LCM preferentially acts on certain types of neurons. (S)-lacosamide decreased the dorsal root ganglion neurons responding to mustard oil, and increased the number of cells responding to menthol. Finally, (S)-LCM reversed thermal hypersensitivity and mechanical allodynia in a model of postoperative pain, and 2 models of neuropathic pain. Thus, using (S)-LCM to inhibit CRMP2 phosphorylation is a novel and efficient strategy to treat pain, which works by targeting specific sensory neuron populations.
慢性疼痛影响着数百万人的生活。目前的治疗方法存在有害的副作用。我们提出了一种针对调节N型电压门控钙（CaV2.2）通道的蛋白质相互作用的策略，作为直接通道阻断的替代方法。使CaV2.2与轴突塌陷反应介导蛋白2（CRMP2）解偶联的肽具有镇痛作用，且对记忆、抑郁和奖赏/成瘾无影响。对能够模拟CaV2.2-CRMP2相互作用解偶联的小分子进行的研究鉴定出了（S）-拉科酰胺[（S）-LCM]，它是美国食品药品监督管理局批准的抗癫痫药物（R）-拉科酰胺[（R）-LCM，Vimpat]的无活性对映体。我们发现，在感觉神经元中，（S）-LCM而非（R）-LCM可抑制细胞周期蛋白依赖性激酶5介导的CRMP2磷酸化，这是驱动CaV2.2活性所必需的一步。（S）-拉科酰胺以低微摩尔浓度的IC50抑制去极化诱导的钙内流。电压钳电生理实验表明，急性应用（S）-LCM后，感觉神经元中的钙电流相应减少。使用星座药理学（一种最近描述的用于神经元功能指纹识别的高内涵表型筛选平台，该平台使用亚型选择性药理剂来阐明定义特定细胞类型的关键信号蛋白的细胞特异性组合（星座）），我们研究了（S）-LCM是否优先作用于某些类型的神经元。（S）-拉科酰胺减少了对芥子油有反应的背根神经节神经元数量，并增加了对薄荷醇有反应的细胞数量。最后，在术后疼痛模型和两种神经性疼痛模型中，（S）-LCM逆转了热超敏反应和机械性异常性疼痛。因此，使用（S）-LCM抑制CRMP2磷酸化是一种治疗疼痛的新颖且有效的策略，其通过靶向特定的感觉神经元群体发挥作用。
