Clock Gene Regulates Kainic Acid-Induced Seizures Through Inhibiting Ferroptosis in Mice
Abstract Temporal lobe epilepsy (TLE) is a common and intractable form of epilepsy. There is a strong need to better understand molecular events underlying TLE and to find novel therapeutic agents. Here we aimed to investigate the role of Clock gene and ferroptosis in regulating TLE. TLE model was established by treating mice with kainic acid (KA). Regulatory effects of Clock gene on KA-induced seizures and ferroptosis were evaluated using Clock knockout (Clock−/−) mice. mRNA and protein levels were determined by quantitative real-time PCR and western blotting, respectively. Ferroptosis was assessed by measuring the levels of iron, GSH and ROS. Transcriptional regulation was studied using a combination of luciferase reporter, mobility shift and chromatin immunoprecipitation (ChIP) assays. We found that Clock ablation exacerbated KA-induced seizures in mice, accompanied by enhanced ferroptosis in the hippocampus. Furthermore, Clock ablation reduced the hippocampal expression of GPX4 and PPAR-γ, two ferroptosis-inhibitory factors, in mice and in N2a cells. Moreover, Clock regulates diurnal expression of GPX4 and PPAR-γ in mouse hippocampus and rhythmicity in KA-induced seizures. Consistently, Clock overexpression up-regulated GPX4 and PPAR-γ, and protected against ferroptosis in N2a cells. In addition, based on luciferase reporter, mobility shift and ChIP assays, we uncovered that CLOCK protein trans-activated Gpx4 and Ppar-γ through specific binding to an E-box element in gene promoters. In conclusion, CLOCK protests against KA-induced seizures through promoting expression of GPX4 and PPAR-γ and inhibiting ferroptosis.