Department of Pharmacology, University of Virginia, Charlottesville, VA 22980, USA.
Computational and Predictive Biology, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
Int J Mol Sci. 2023 Jul 12;24(14):11347. doi: 10.3390/ijms241411347.
Over a third of patients with temporal lobe epilepsy (TLE) are not effectively treated with current anti-seizure drugs, spurring the development of gene therapies. The injection of adeno-associated viral vectors (AAV) into the brain has been shown to be a safe and viable approach. However, to date, AAV expression of therapeutic genes has not been regulated. Moreover, a common property of antiepileptic drugs is a narrow therapeutic window between seizure control and side effects. Therefore, a long-term goal is to develop drug-inducible gene therapies that can be regulated by clinically relevant drugs. In this study, a first-generation doxycycline-regulated gene therapy that delivered an engineered version of the leak potassium channel (TREK-M) was injected into the hippocampus of male rats. Rats were electrically stimulated until kindled. EEG was monitored 24/7. Electrical kindling revealed an important side effect, as even low expression of TREK M in the absence of doxycycline was sufficient to cause rats to develop spontaneous recurring seizures. Treating the epileptic rats with doxycycline successfully reduced spontaneous seizures. Localization studies of infected neurons suggest seizures were caused by expression in GABAergic inhibitory neurons. In contrast, doxycycline increased the expression of TREK-M in excitatory neurons, thereby reducing seizures through net inhibition of firing. These studies demonstrate that drug-inducible gene therapies are effective in reducing spontaneous seizures and highlight the importance of testing for side effects with pro-epileptic stressors such as electrical kindling. These studies also show the importance of evaluating the location and spread of AAV-based gene therapies in preclinical studies.
超过三分之一的颞叶癫痫 (TLE) 患者对当前的抗癫痫药物治疗反应不佳，这促使了基因治疗的发展。将腺相关病毒载体 (AAV) 注射到大脑中已被证明是一种安全可行的方法。然而，迄今为止，治疗基因的 AAV 表达尚未得到调节。此外，抗癫痫药物的一个共同特性是在控制癫痫发作和副作用之间存在狭窄的治疗窗口。因此，长期目标是开发可由临床相关药物调节的药物诱导型基因治疗。在这项研究中，第一代强力霉素调控的基因治疗方法将一种经过工程改造的渗漏钾通道 (TREK-M) 递送到雄性大鼠的海马体中。通过电刺激使大鼠产生癫痫发作。24/7 监测 EEG。脑电图监测揭示了一个重要的副作用，即即使在没有强力霉素的情况下，TREK-M 的低表达也足以导致大鼠自发出现反复发作的癫痫。用强力霉素治疗癫痫大鼠成功地减少了自发性癫痫发作。感染神经元的定位研究表明，癫痫发作是由 GABA 能抑制性神经元表达引起的。相比之下，强力霉素增加了兴奋性神经元中 TREK-M 的表达，从而通过抑制放电来减少癫痫发作。这些研究表明，药物诱导型基因治疗在减少自发性癫痫发作方面是有效的，并强调了在使用电刺激等致癫痫应激源进行测试时，需要注意潜在的副作用。这些研究还表明了在临床前研究中评估基于 AAV 的基因治疗的位置和传播的重要性。
