Sustained Increase in DNMT1/DNMT3a expression in response to initial precipitating injury in lithium-´pilocarpine epileptic model

DANTE GOMEZ CUAUTLE; ALBERTO JAVIER RAMOS; ALICIA ROSSI; VERONICA MURTA

Congreso; Reunión de Sociedades de Biociencias 2020; 2020

SAIC

Sustained increase in DNMT1 / DNMT3a expression in response to initial precipitating injury in lithium-pilocarpine epileptic model.Autores: Dante Gomez Cuautle, Alicia Rossi, Veronica Murta, Alberto Javier RamosRetrospective studies have shown that temporary lobe epilepsy (TLE) patients refer an initial precipitating event (IPE) during early childhood and a subsequent latency period in which seizures are absent. Latency period is a poorly studied subject in epilepsy, but it is proposed that essential steps in the epileptogenesis occur in this period. The lithium-pilocapine model of epilepsy represents most characteristics of human TLE in experimental animals, including an IPE followed by a latency period. Epigenetics changes in the latency period are starting to be described and the important astroglial genes, such as Kir4.1 involved in K+ homeostasis, are heavily epigenetically-regulated genes. We here induced and IPE (status epilepticus, SE) in male Wistar rats by administering 3 mEq/kg LiCl and 30 mg/kg pilocarpine. SE lasted for 20 min and then seizures were stopped with 20 mg/kg diazepam. Animals were sacrificed at 7 or 21 days post-SE (DPSE) and brains processed for biochemistry or fixed for immunofluorescence. We observed that Kir4.1 expression was reduced in the hippocampal and cortical astrocytes concomitantly with increased GFAP expression and reactive gliosis in these areas. Kir4.1 gene (KCNJ10) decreased mRNA was also shown by RT-PCR and we consistently noticed an increase in the expression of DNMT1 and DNMT3a at 7- and 21DPSE. By performing in silico analysis, we have also observed that proximal DNMT1 and DNMT3a promoters have consensus sites for NF-kB and Stat3 transcription factors that are known to be activated in reactive astrocytes. Considering published evidence regarding the participation of DNMT1 in the regulation of KCNJ10 in astrocytes, we here propose that the observed astroglial Kir4.1 downregulation induced by the SE-induced IPE is probably lying downstream of reactive astrogliosis, NF-kB/Stat3 activation and increased DNMT activity.Supported by grants: PICT 2017-2203; UBACYT; PIP CONICET 479.