4BRAIN, Department of Neurology, Ghent University, Corneel Heymanslaan 10, 9000, Ghent, Belgium.
Medical Image and Signal Processing, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium.
Neurotherapeutics. 2022 Jan;19(1):342-351. doi: 10.1007/s13311-021-01160-0. Epub 2021 Dec 3.
Expression of inhibitory designer receptors exclusively activated by designer drugs (DREADDs) on excitatory hippocampal neurons in the hippocampus represents a potential new therapeutic strategy for drug-resistant epilepsy. To overcome the limitations of the commonly used DREADD agonist clozapine, we investigated the efficacy of the novel DREADD ligand JHU37160 in chemogenetic seizure suppression in the intrahippocampal kainic acid (IHKA) mouse model for temporal lobe epilepsy (TLE). In addition, seizure-suppressing effects of chemogenetics were compared to the commonly used anti-epileptic drug (AED), levetiracetam (LEV). Therefore, an adeno-associated viral vector was injected in the sclerotic hippocampus of IHKA mice to induce expression of a tagged inhibitory DREADD hM4Di or only a tag (control) specifically in excitatory neurons using the CamKIIα promoter. Subsequently, animals were treated with LEV (800 mg/kg), clozapine (0.1 mg/kg), and DREADD ligand JHU37160 (0.1 mg/kg) and the effect on spontaneous seizures was investigated. Clozapine and JHU37160-mediated chemogenetic treatment both suppressed seizures in DREADD-expressing IHKA mice. Clozapine treatment suppressed seizures up to 34 h after treatment, and JHU37160 effects lasted for 26 h after injection. Moreover, both compounds reduced the length of seizures that did occur after treatment up to 28 h and 18 h after clozapine and JHU37160, respectively. No seizure-suppressing effects were found in control animals using these ligands. Chemogenetic seizure treatment suppressed seizures during the first 30 min after injection, and seizures remained suppressed during 8 h following treatment. Chemogenetics thus outperformed effects of levetiracetam (p < 0.001), which suppressed seizure frequency with a maximum of 55 ± 9% for up to 1.5 h (p < 0.05). Only chemogenetic and not levetiracetam treatment affected the length of seizures after treatment (p < 0.001). These results show that the chemogenetic therapeutic strategy with either clozapine or JHU37160 effectively suppresses spontaneous seizures in the IHKA mouse model, confirming JHU37160 as an effective DREADD ligand. Moreover, chemogenetic therapy outperforms the effects of levetiracetam, indicating its potential to suppress drug-resistant seizures.
在海马体中兴奋性海马神经元上表达抑制性 Designer 受体专门激活 Designer 药物 (DREADD) 代表了一种治疗耐药性癫痫的新的潜在治疗策略。为了克服常用 DREADD 激动剂氯氮平的局限性，我们研究了新型 DREADD 配体 JHU37160 在海马内海人酸 (IHKA) 小鼠颞叶癫痫 (TLE) 模型中的化学遗传学抑制性癫痫发作的疗效。此外，还将化学遗传学的抗癫痫作用与常用的抗癫痫药物 (AED) 左乙拉西坦 (LEV) 进行了比较。因此，通过腺相关病毒载体将标签化的抑制性 DREADD hM4Di 或仅标签 (对照) 在兴奋性神经元中使用 CamKIIα 启动子特异性表达于 IHKA 小鼠的硬化海马体中。随后，用 LEV (800mg/kg)、氯氮平 (0.1mg/kg) 和 DREADD 配体 JHU37160 (0.1mg/kg) 处理动物，并研究其对自发性癫痫发作的影响。氯氮平和 JHU37160 介导的化学遗传学治疗均可抑制 DREADD 表达的 IHKA 小鼠的癫痫发作。氯氮平治疗可抑制癫痫发作，直至治疗后 34 小时，而 JHU37160 的作用可持续至注射后 26 小时。此外，两种化合物均使治疗后发生的癫痫发作的持续时间减少了 28 小时和 18 小时，分别为 28 小时和 18 小时。在使用这些配体的对照动物中未发现有抗癫痫作用。化学遗传学治疗在注射后 30 分钟内抑制癫痫发作，并且在治疗后 8 小时内仍保持抑制作用。因此，化学遗传学的效果优于左乙拉西坦 (p<0.001)，后者最大可将癫痫发作频率抑制 55±9%，持续时间长达 1.5 小时 (p<0.05)。只有化学遗传学而非左乙拉西坦治疗影响治疗后癫痫发作的持续时间 (p<0.001)。这些结果表明，氯氮平或 JHU37160 的化学遗传学治疗策略均可有效抑制 IHKA 小鼠模型中的自发性癫痫发作，证实 JHU37160 是一种有效的 DREADD 配体。此外，化学遗传学治疗优于左乙拉西坦的作用，表明其具有抑制耐药性癫痫发作的潜力。
