Study On The Expression And Potential Role Of Bmal1 During Limbic Epileptogenesis

Background: Limbic epilepsy is a common devastating neurological disorder that always becomes refractory.However,the molecular and cellular mechanisms underlying its pathogenesis remain largely unclear so far.In recent years,studies indicated that circadian factors play an important role in the process of epilepsy.As a core transcript factor regulating circadian rhythms,BMAL1 was recently shown to affect neuronal excitability and it can regulate the balance of excitatory and inhibitory neurotransmitters in the brain.The balance implies that BMAL1 may play a key regulatory role in the development of epilepsy,and the related biological functions are worthy further investigation.We suspect that BMAL1 is involved in limbic epileptogenesis.Objectives : To explore the expression of transcription factor BMAL1 in epileptic brain susceptible regions.Investigate the expression changes of transcription factor BMAL1 after epileptiform activity.Analyze the relationship between epileptic seizure and preliminarily explore its role and mechanism in the pathogenesis of epilepsy.Methods: 1.RT-PCR,Real-time PCR,Western Blot and immunofluorescence staining were used to observe the expression pattern and spatial distribution of Bmal1 gene in the brain or other tissues from mice.2.RT-PCR,Real-time PCR or Western Blot were used to observe the expression pattern of Bmal1 gene in brain from different mouse models,including pilocarpine or kainic acid(KA)-induced epilepsy,electrical stimulation(Kindling).3.Bmal1 knockout mice were introduced to detect the effect of Bmal1 gene deletion in the development of epileptic.4.We successfully generated distinct lines of conditional knockout methods of Bmal1 mediated by Cre/lox P strategies,to selectively ablate Bmal1 proteins in different subsets of neurons in the mouse brain.Then,by constructing an electric stimulation models,we explored the development of epileptic activity.Results: In our work,we found that Bmal1 is expressed in the cortex and hippocampus,both of which are key brain areas for epileptic seizures.Immunofluorescence staining experiments showed that Bmal1 is expressed in neurons and glial cells.Thus,we used classic temporal lobe epilepsy model,pilocarpine-induced epilepsy model,and found that Bmal1 gene expression was responsive to seizure activity in animal models.Then,we generated distinct lines of conditional knockouts of Bmal1 using Cre/Loxp-mediated c KO strategies,to selectively ablated Bmal1 proteins in different subsets of cells in the mouse brain.Our results suggested that the Bmal1 gene may play an important role in the process of epileptic seizures.Conclusion: In this study,we showed that Bmal1 may be an important regulatory factor in the development of epilepsy.We believe that this work will provide novel insights of transcription factors into the mechanisms underlying pathogenesis of limbic epilepsy;meanwhile,it will improve our new understanding of the pathogenesis of limbic epilepsy,and provide a scientific basis for the development of novel strategies for epilepsy prevention and treatment from the perspective of biological rhythm.