Department of Geriatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325000, Zhejiang Province, China.
Department of Neurology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325000, Zhejiang, China.
Neurobiol Dis. 2024 Apr;193:106457. doi: 10.1016/j.nbd.2024.106457. Epub 2024 Feb 28.
Epilepsy is a brain disorder affecting up to 1 in 26 individuals. Despite its clinical importance, the molecular mechanisms of epileptogenesis are still far from clarified. Our previous study showed that disruption of Clock in excitatory neurons alters cortical circuits and leads to generation of focal epilepsy. In this study, a GAD-Cre;Clock mouse line with conditional Clock gene knockout in inhibitory neurons was established. We observed that seizure latency was prolonged, the severity and mortality of pilocarpine-induced seizure were significantly reduced, and memory was improved in GAD-Cre;Clock mice. We hypothesize that mice with CLOCK knockout in inhibitory neurons have increased threshold for seizure, opposite from mice with CLOCK knockout in excitatory neurons. Further investigation showed Clock knockout in inhibitory neurons upregulated the basal protein level of ARC, a synaptic plasticity-associated immediate-early gene product, likely through the BDNF-ERK pathway. Altered basal levels of ARC may play an important role in epileptogenesis after Clock deletion in inhibitory neurons. Although sEPSCs and intrinsic properties of layer 5 pyramidal neurons in the somatosensory cortex exhibit no changes, the spine density increased in apical dendrite of pyramidal neurons in CLOCK knockout group. Our results suggest an underlying mechanism by which the circadian protein CLOCK in inhibitory neurons participates in neuronal activity and regulates the predisposition to epilepsy.
癫痫是一种影响多达 1/26 个人的大脑疾病。尽管其具有临床重要性，但癫痫发生的分子机制仍远未阐明。我们之前的研究表明，兴奋性神经元中 Clock 的破坏会改变皮质回路并导致局灶性癫痫的产生。在这项研究中，建立了一种条件性 Clock 基因敲除的抑制性神经元中的 GAD-Cre;Clock 小鼠品系。我们观察到，GAD-Cre;Clock 小鼠的癫痫潜伏期延长，匹罗卡品诱导的癫痫的严重程度和死亡率显著降低，记忆得到改善。我们假设抑制性神经元中 CLOCK 敲除的小鼠具有更高的癫痫发作阈值，与兴奋性神经元中 CLOCK 敲除的小鼠相反。进一步的研究表明，抑制性神经元中的 Clock 敲除上调了 ARC 的基础蛋白水平，ARC 是一种与突触可塑性相关的即时早期基因产物，可能通过 BDNF-ERK 途径。抑制性神经元中 Clock 缺失后，ARC 的基础水平改变可能在癫痫发生中发挥重要作用。尽管体感皮层第 5 层锥体神经元的 sEPSCs 和固有特性没有变化，但 CLOCK 敲除组锥体神经元的树突棘密度增加。我们的结果表明，抑制性神经元中的生物钟蛋白 CLOCK 通过参与神经元活动并调节癫痫易感性的潜在机制参与其中。
