Epileptogenesis, induced by status epilepticus (SE), is a chronic process, and intervention in this progress may prevent chronic epilepsy. It has been proposed that DNA methylation might be related with epileptogenesis. RASgrf1 has a differentially methylated region at the promoter which can silence gene expression. We have previously observed the down-regulation of RASgrf1 in epilepsy patients and proved that hypermethylation of RASgrf1 reaches maximal level at the latent period in mice after kainate-induced SE (KA mice), with corresponding alteration of RASgrf1 expression. In the present study, N-phthalyl-L-tryptophan (RG108), a DNA methyltransferase inhibitor, was applied in KA mice at latent phase and the behavior, electroencephalogram and pathological changes were observed in chronic phase. Methylation and expression of RASgrf1 were determined by polymerase chain reaction (PCR), western blotting, and bisulfite sequencing PCR. The results showed that the incidence of spontaneous recurrent seizures (SRS) was significantly lower in the RG108 group than the normal saline (NS) group. Subgroup analysis showed significant hypermethylation and lower expression of RASgrf1 in the RG108–SRS subgroup and the NS–SRS subgroup but not in the RG108–NSRS (no SRS) subgroup and the NS–NSRS subgroup compared with the control group. No significant difference was found between the RG108–SRS and NS–SRS subgroups. Meanwhile, hippocampal neuronal loss was observed in RG108–SRS and NS–SRS subgroups. We thus demonstrated that RG108 could modify the progression of epileptogenesis after KA induced SE and prevent chronic epilepsy. Meanwhile, hypermethylation of RASgrf1 after KA induced SE could be reversed with corresponding changes of RASgrf1 expression. Additionally, we speculated that RASgrf1 might be a potential epigenetic mediator in epileptogenesis and chronic epilepsy.
RASgrf1 DNA methylation RG108 Epilepsy Epileptogenesis
This is a preview of subscription content, log in to check access.
This work was supported by the National Natural Science Foundation of China (Grant Numbers 81071040, 81471320).
Compliance with Ethical Standards
Conflict of interest
None of the authors has any conflicts of interest to disclose.
Brodie MJ (2016) Pharmacological treatment of drug-resistant epilepsy in adults: a practical guide. Curr Neurol Neurosci Rep 16(9):82CrossRefGoogle Scholar
Pitkanen A, Lukasiuk K (2011) Mechanisms of epileptogenesis and potential treatment targets. Lancet Neurol 10(2):173–186CrossRefGoogle Scholar
Goldberg EM, Coulter DA (2013) Mechanisms of epileptogenesis: a convergence on neural circuit dysfunction. Nat Rev Neurosci 14(5):337–349CrossRefGoogle Scholar
Younus I, Reddy DS (2017) Epigenetic interventions for epileptogenesis: a new frontier for curing epilepsy. Pharmacol Ther 177:108–122CrossRefGoogle Scholar
Hwang JY, Aromolaran KA, Zukin RS (2013) Epigenetic mechanisms in stroke and epilepsy. Neuropsychopharmacology 38(1):167–182CrossRefGoogle Scholar
Kobow K, Blumcke I (2012) The emerging role of DNA methylation in epileptogenesis. Epilepsia 53(Suppl 9):11–20CrossRefGoogle Scholar
Wang L et al (2016) DNA methylation profiling reveals correlation of differential methylation patterns with gene expression in human epilepsy. J Mol Neurosci 59(1):68–77CrossRefGoogle Scholar
Miller-Delaney SF et al (2015) Differential DNA methylation profiles of coding and non-coding genes define hippocampal sclerosis in human temporal lobe epilepsy. Brain 138(Pt 3):616–631CrossRefGoogle Scholar
Kobow K et al (2013) Deep sequencing reveals increased DNA methylation in chronic rat epilepsy. Acta Neuropathol 126(5):741–756CrossRefGoogle Scholar
Miller-Delaney SF et al (2012) Differential DNA methylation patterns define status epilepticus and epileptic tolerance. J Neurosci 32(5):1577–1588CrossRefGoogle Scholar
Krapivinsky G et al (2003) The NMDA receptor is coupled to the ERK pathway by a direct interaction between NR2B and RASgrf1. Neuron 40(4):775–784CrossRefGoogle Scholar
Zhu Q et al (2013) Decreased expression of Ras-GRF1 in the brain tissue of the intractable epilepsy patients and experimental rats. Brain Res 1493:99–109CrossRefGoogle Scholar
Stafstrom CE, Thompson JL, Holmes GL (1992) Kainic acid seizures in the developing brain: status epilepticus and spontaneous recurrent seizures. Brain Res Dev Brain Res 65(2):227–236CrossRefGoogle Scholar
Yang Y et al (2017) Chronic metformin treatment facilitates seizure termination. Biochem Biophys Res Commun 484(2):450–455CrossRefGoogle Scholar