The Sigma1 protein as a target for therapeutic management of epilepsy: preclinical validation in chronic mouse models

抗癫痫药物的慢性管理是兽药和人用药中癫痫治疗管理的支柱之一。不幸的是，在相关数量的患者中没有取得令人满意的治疗成功和癫痫控制。此外，大多数现有的药物都是为了抑制癫痫发作而开发的，但还没有设计成针对病理生理机制和发挥疾病修饰作用。疾病修饰方法的发展有希望产生更有效的策略，帮助减少疾病的内在严重程度并克服耐药性。Sigma1是一种位于内质网膜上的非典型受体蛋白，具有伴侣蛋白的功能。在细胞应激反应中，Sigma1影响er -线粒体界面的钙信号，并在转运到细胞膜后，与不同的离子通道和受体相互作用。虽然Sigma1在正常细胞和基底细胞功能中似乎没有发挥主要作用，但当疾病状态下的稳态受到病理生理机制的威胁时，它似乎具有重要的保护和调节功能。因此，Sigma1被认为是一个有希望的靶点，具有介导疾病修饰作用的潜力。在我们的项目中，我们将研究两种不同小鼠癫痫模型组织中Sigma1表达的保存和疾病相关调控。然后，我们将讨论Sigma1的遗传和药理学靶向影响癫痫阈值、癫痫参数和过度兴奋网络发展的假设。此外，还将评估对行为改变的影响。将在两种慢性小鼠癫痫模型中研究各自的作用，即杏仁核点燃范式与反复发作诱导和海马内盐模型与自发反复发作的发展。通过比较Sigma1基因敲除小鼠和野生型小鼠，将探讨Sigma1基因缺失的后果。以下Sigma1配体的药理学靶标将被测试：E1R作为选择性正变构调节剂；NE-100作为选择性拮抗剂；芬氟拉明联合作用机制及对血清素能信号和Sigma1的影响。此外，我们将测试与NE-100的药物组合，以确认该化合物与Sigma1相互作用对E1R的相关性，并确定该化合物与Sigma1相互作用对芬氟拉明的相对贡献。期望实验结果为未来有助于克服耐药性的新型疾病修饰方法的转化开发提供基础。

Chronic administration of antiseizure drugs represents one of the mainstays for therapeutic management of epilepsy in veterinary and human medicine. Unfortunately, a satisfactory therapeutic success and seizure control is not achieved in a relevant number of patients. Moreover, the majority of available drugs have been developed to suppress seizures, but have not been designed to target pathophysiological mechanisms and to exert disease-modifying effects. The development of disease-modifying approaches holds the promise to result in more efficacious strategies helping to reduce the intrinsic severity of the disease and to overcome drug resistance. Sigma1 is an atypical receptor protein that is located in the endoplasmic reticulum membrane and serves a chaperone function. In response to cell stress Sigma1 affects calcium signaling at the ER-mitochondrial interface and, upon translocation to the cell membrane, interacts with different ion channels and receptors. While Sigma1 does not seem to play a major role in normal and basal cell function, it seems to serve an important protective and regulatory function, when homeostasis is threatened by pathophysiological mechanisms in disease states. Therefore, Sigma1 is considered as a promising target with the potential to mediate disease-modifying effects. In our project, we will study the preservation and disease-associated regulation of Sigma1 expression in tissue from two different mouse epilepsy models. We will then address the hypothesis that genetic and pharmacological targeting of Sigma1 affects seizure thresholds, seizure parameters, and development of a hyperexcitable network. In addition, the impact on behavioral alterations will be assessed. Respective effects will be studied in two chronic mouse epilepsy models, the amygdala kindling paradigm with repeated seizure induction and the intrahippocampal kainate model with development of spontaneous recurrent seizures. The consequences of Sigma1 genetic deficiency will be explored by comparison between Sigma1 knockout and wildtype mice. For pharmacological targeting the following Sigma1 ligands will be tested: E1R as a selective positive allosteric modulator; NE-100 as a selective antagonist; fenfluramine with combined mechanism of action with effects on serotonergic signaling and Sigma1. In addition, we will test drug combinations with NE-100 to confirm the relevance of the compound’s interaction with Sigma1 for E1R and to determine the relative contribution of the compound’s interaction with Sigma1 for fenfluramine. It is expected that the experimental findings provide a basis for future translational development of novel disease-modifying approaches that help to overcome drug resistance.