Maternal methyl-enriched diet in rat reduced the audiogenic seizure proneness in progeny I.I. Poletaeva a, ⁎, N.M. Surina a,1 , V.V. Ashapkin b,2 , I.B. Fedotova a,1 , I.B. Merzalov c,3 , O.V. Perepelkina a,1 , G.V. Pavlova c,3 a Biology Faculty, Moscow State University, Leninskie Gori, 1, build. 12, Moscow 119992, Russia b Belozersky Institute of Physical-Chemical Biology, Moscow State University, Leninskie Gori, 1, build. 40, Moscow 119992, Russia c Institute of Gene Biology, Russian Academy of Sciences, Vavilova str., 34/5, Moscow 119334, Russia abstract article info Article history: Received 26 January 2014 Received in revised form 23 September 2014 Accepted 26 September 2014 Available online 5 October 2014 Keywords: Audiogenic epilepsy Methyl enriched diet DNA methylation Audiogenic epilepsy proneness was analyzed in the progeny of rats from two strains (audiogenic seizure prone— strain “4”—and audiogenic seizure non-prone, strain “0”). Females were fed by a diet which contained substances enriched with methyl-groups during 1 week before mating (MED), during pregnancy period and 1 week after the delivery. This MED treatment resulted in a decrease of audiogenic seizure fit intensity, which was more evident in rats of strain “0”. Control rats of strain “4” displayed intense seizures (tonic seizure, 3.85 arbitrary units). Med “4” rats seizures were less intense (3.23, tonic seizure of lower intensity), control “0” strain rats demonstrated the seizure with mean 3.09 arbitrary units, “0” MED rats only 2.03 arbitrary unit intensity (only clonic seizures, significantly, p b 0.05, different from controls). Methyl-enriched diet resulted in the significant changes in methylation status of several genes (Cpne6, Gtf2i, Sctr,1 Sfmbt, Phe2). These genes among others were chosen for analysis as their expression was analyzed in other methylation study. These genes were hypermethylated after “epileptic tolerance”. Due to this procedure, the intensity of status epilepticus, produced by kainate in mice, decreased (Miller-Delaney et al., 2012). The modulation of audiogenic seizure intensity as the result of methyl-enriched diet during prenatal and early postnatal ontogeny was demonstrated for the first time. © 2014 Elsevier Inc. All rights reserved. 1. Introduction The genetic predisposition to seizure development was described both in humans (see EPICURE Consortium and EMINet Consortium, 2012; Helbig and Lowenstein, 2013) and in animals (Coppola and Moshé, 2012). As it was demonstrated the processes of brain develop- ment are also under epigenetic control, and it is now possible to analyze the role of epigenetic processes and namely the DNA methylation in epileptogenesis (Schatz et al., 1983; Lester et al., 2011; Hwang et al., 2013; Kobow et al., 2009; Kobow and Blümcke, 2011). The role of DNA methylation in epileptogenesis was investigated in animal experiments (see Sellinger et al., 1986; Tsankova et al., 2004; Miller-Delaney et al., 2012) and in clinic (Kobow and Blümcke, 2012). Gene MBD5 (the product -methyl-CpG binding domain protein 5) is the member of methyl-binding group of genes, and it probably participates in brain DNA methylation (Noh and Graham, 2012). The deletion of this gene, found in humans, was accompanied by severe CNS dysfunction, including seizures and developmental delay (Motobayashi et al., 2012). The patterns of gene expression, which are presumably determined (among other factors) by changes in epigenetic processes, vary in animal models of epilepsy (Kobow et al., 2013). Human brain DNA methylation and epilepsy are shown to be connected. Miller-Delaney et al. (2012) analyzed the effects of seizure preconditioning using status epilepticus (SE) model (seizures induced in C57BL/6 mice by intra-amygdala microinjections of kainic acid). The preconditioning procedure included i.p. injection of kainic acid before SE induction, which promoted seizure tolerance. Based on genome- wide DNA methylation analysis authors discovered changes in methylation status of 288 genes (in hippocampal tissue), and 15 genes from this group were differentially hypermethylated (in comparison to SE group) in the case when pre-conditioning + SE procedures were used. Most of these genes were “novel” and not known previously to be implicated in SE tolerance mechanisms. The study of epigenetic mechanisms involved in seizure development includes usually the comparison of brain DNA methylation patterns during seizures (or immediately after seizures) vs a normal state. Using this approach changes were found in the methylation level of several genes (Doyle and Sellinger, 1980; Sellinger et al., 1986). At the same time practically no data exist concerning the role of DNA Pharmacology, Biochemistry and Behavior 127 (2014) 21–26 ⁎ Corresponding author at: Biology Faculty, Moscow State University, Leninskie Gori, 1, build. 12, Russia. Tel.: +7 495 9394468; fax: +7 495 9392837. E-mail addresses: ingapoletaeva@mail.ru (I.I. Poletaeva), ashapkin@genebee.msu.su (V.V. Ashapkin). 1 Tel.: +7 495 9394468; fax: +7 495 9392837. 2 Tel.: +7 495 939 53 59. 3 Tel.: +7 499 1352541. http://dx.doi.org/10.1016/j.pbb.2014.09.018 0091-3057/© 2014 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Pharmacology, Biochemistry and Behavior journal homepage: www.elsevier.com/locate/pharmbiochembeh