Vezatin Regulates Seizures by Controlling AMPAR-Mediated Synaptic Activity

Background: The role of vezatin in epilepsy remains unknown. Therefore, the aim of the present study was to investigate the underlying roles of vezatin in epilepsy. Methods: The expression pattern of vezatin in epilepsy in vivo and in vitro was investigated by immunofluorescence and western blotting. Pilocarpine (PILO)-induced epileptic mice were subjected to behavioral tests to determine the role of vezatin in regulating seizure activity. Whole-cell patch-clamp recordings were obtained via multiple biochemical techniques to explore the mechanism by which vezatin regulates seizure activity. Findings: Vezatin expression was increased in hippocampal tissues from PILO-induced epileptic mice, brain tissues from patients with temporal lobe epilepsy (TLE), and a Mg2+ -free medium-induced vitro seizure model (VSM). Vezatin knockdown suppressed seizure activity in PILO-induced epileptic mice. Mechanistically, vezatin knockdown suppressed AMPAR-mediated synaptic events in epileptic mice and downregulated the surface expression of AMPAR GluA1 subunit (GluA1). Interestingly, vezatin knockdown decreased the phosphorylation of GluA1 at serine 845 and reduced protein kinase A (PKA) phosphorylation; when PKA phosphorylation was suppressed by H-89 (a selective inhibitor of PKA phosphorylation) in vitro, the downregulatory effects of vezatin knockdown on the phosphorylation of GluA1 at serine 845 and the surface expression of GluA1 were blocked. Interpretation: We showed that the expression pattern of vezatin in epilepsy is abnormal and demonstrated the mechanism by which vezatin regulates seizure activity. Vezatin can modulate the phosphorylation of GluA1 at serine 845, which requires PKA signaling activation, further regulating the surface expression of GluA1 and affecting AMPAR-mediated neuronal synaptic transmission (NST). Funding Statement: This study was supported by the National Science Foundation of China (No. 81901315, No.81901330, and No.81771390) and supported by the Kuanren Talents Program of the Second Affiliated Hospital of Chongqing Medical University (No. kryc-yq-2123), China. Declaration of Interests: None of the authors have conflicts of interest. Ethics Approval Statement: The human study complied with the Declaration of Helsinki and the ethical principles of the National Institutes of Health and was approved by the Committee on Human Research of the Second Affiliated Hospital of Chongqing Medical University. All animal experiments performed in the present study were approved by the Committee on Animal Research of Chongqing Medical University and were conducted in accordance with international guidelines for animal studies and the guidelines of the Committee on Animal Research of Chongqing Medical University, Chongqing, China.