Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229.
Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229.
eNeuro. 2023 Jul 24;10(7). doi: 10.1523/ENEURO.0047-22.2023. Print 2023 Jul.
About one-third of individuals living with epilepsy have treatment-resistant seizures. Alternative therapeutic strategies are thus urgently needed. One potential novel treatment target is miRNA-induced silencing, which is differentially regulated in epilepsy. Inhibitors (antagomirs) of specific microRNAs (miRNAs) have shown therapeutic promise in preclinical epilepsy studies; however, these studies were mainly conducted in male rodent models, and research into miRNA regulation in females and by female hormones in epilepsy is scarce. This is problematic because female sex and the menstrual cycle can affect the disease course of epilepsy and may, therefore, also alter the efficacy of potential miRNA-targeted treatments. Here, we used the proconvulsant miRNA miR-324-5p and its target, the potassium channel Kv4.2, as an example to test how miRNA-induced silencing and the efficacy of antagomirs in epilepsy are altered in female mice. We showed that Kv4.2 protein is reduced after seizures in female mice similar to male mice; however, in contrast to male mice, miRNA-induced silencing of Kv4.2 is unchanged, and miR-324-5p activity, as measured by the association with the RNA-induced silencing complex, is reduced in females after seizure. Moreover, an miR-324-5p antagomir does not consistently reduce seizure frequency or increase Kv4.2 in female mice. As a possible underlying mechanism, we found that miR-324-5p activity and the silencing of Kv4.2 in the brain were differentially correlated with plasma levels of 17β-estradiol and progesterone. Our results suggest that hormonal fluctuations in sexually mature female mice influence miRNA-induced silencing and could alter the efficacy of potential future miRNA-based treatments for epilepsy in females.
大约三分之一的癫痫患者有治疗抵抗性癫痫发作。因此，迫切需要替代治疗策略。一种潜在的新治疗靶点是 miRNA 诱导的沉默，其在癫痫中存在差异调节。在癫痫的临床前研究中，特定 microRNA (miRNA) 的抑制剂（antagomirs）显示出了治疗潜力；然而，这些研究主要在雄性啮齿动物模型中进行，而关于女性中 miRNA 调节以及女性激素对癫痫的影响的研究则很少。这是有问题的，因为女性性别和月经周期会影响癫痫的病程，因此也可能改变潜在的 miRNA 靶向治疗的疗效。在这里，我们使用促惊厥 miRNA miR-324-5p 及其靶标钾通道 Kv4.2 作为一个例子，来测试 miRNA 诱导的沉默及其在癫痫中的疗效在雌性小鼠中是如何改变的。我们发现，与雄性小鼠相似，雌性小鼠在癫痫发作后 Kv4.2 蛋白减少；然而，与雄性小鼠不同的是，Kv4.2 的 miRNA 诱导沉默没有改变，并且 miR-324-5p 的活性，如通过与 RNA 诱导沉默复合物的关联来测量，在雌性小鼠中在癫痫发作后降低。此外，miR-324-5p antagomir 并不总是能降低雌性小鼠的癫痫发作频率或增加 Kv4.2。作为一种潜在的机制，我们发现，miR-324-5p 的活性和 Kv4.2 在大脑中的沉默与血浆中 17β-雌二醇和孕酮的水平呈不同的相关性。我们的研究结果表明，性成熟雌性小鼠中激素波动会影响 miRNA 诱导的沉默，并可能改变未来针对女性癫痫的潜在 miRNA 治疗的疗效。
