School of pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.
ACS Chem Neurosci. 2024 Jan 3;15(1):205-214. doi: 10.1021/acschemneuro.3c00744. Epub 2023 Dec 19.
Epilepsy is a chronic disease of brain dysfunction, which arises from imbalance between excitatory and inhibitory activities in neural circuits. Previously, we reported that peptide Martentoxin (MarTX), from scorpion Buthus martensii Karsch, displayed antiseizure activities by specifically inhibiting BK(α + β4) channel currents. Injection of MarTX into the hippocampal region of mice significantly alleviated convulsive seizures. However, intravenous injection of MarTX had no antiepileptic efficacy due to the blood-brain barrier (BBB). To address this, here, we designed cell-penetrating peptide TAT-modified MarTX, in which the linker containing three glycines was put between TAT and the N-terminus of MarTX (forming MTX-N-TAT) or between TAT and the C-terminus of MarTX (forming MTX-C-TAT), respectively. We prepared them in a large amount through overexpression system and then probed their antiseizure activities. Our results indicated that intravenous injection of MTX-C-TAT showed significant therapeutic efficacy of antiseizure. It increased seizure latency, reduced the total seizure duration and the number of seizures at stages 3, 4, and 5, inhibited hippocampal neuronal hyperexcitability, and exhibited neuroprotective effects on hippocampal neurons. These studies implied that MTX-C-TAT displayed intravenous antiseizure activities properly through crossing BBB and would be a potential antiepileptic drug in the future.
癫痫是一种大脑功能障碍的慢性疾病，源于神经回路中兴奋和抑制活动的失衡。此前，我们报道了来自蝎子 Buthus martensii Karsch 的肽 Martentoxin（MarTX）通过特异性抑制 BK(α + β4)通道电流显示出抗惊厥活性。将 MarTX 注射到小鼠的海马区可显著缓解惊厥发作。然而，由于血脑屏障（BBB）的存在，MarTX 静脉注射没有抗癫痫作用。为了解决这个问题，我们设计了细胞穿透肽 TAT 修饰的 MarTX，其中含有三个甘氨酸的接头分别放在 TAT 和 MarTX 的 N 端之间（形成 MTX-N-TAT）或 TAT 和 MarTX 的 C 端之间（形成 MTX-C-TAT）。我们通过过表达系统大量制备了它们，然后探测了它们的抗惊厥活性。我们的结果表明，MTX-C-TAT 的静脉注射表现出显著的抗惊厥治疗效果。它增加了癫痫发作潜伏期，减少了总癫痫发作持续时间和 3、4、5 期的癫痫发作次数，抑制了海马神经元的过度兴奋，并对海马神经元表现出神经保护作用。这些研究表明，MTX-C-TAT 通过穿过 BBB 表现出适当的静脉内抗惊厥活性，将来可能成为一种潜在的抗癫痫药物。
