SUSTAINED INCREASE IN DNMT1 AND DNMT3A EXPRESSION IN RESPONSE TO THE INITIAL PRECIPITATING INJURY IN LITHIUM-PILOCARPINE EPILEPTIC MODEL.

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

Modalidad virtual

Congreso; REUNIÓN DE SOCIEDADES DE BIOCIENCIAS 2020; 2020

SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC)

Retrospective studies have shown that temporal 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 epileptogenesis occur during this period. The lithium-pilocapine model presents most of the characteristics of human TLE in experimental animals, including an IPE followed by a latency period. Epigenetics changes in the latency period have been described. On the other hand, important astroglial genes, such as Kir4.1 which is involved in K+ homeostasis, are heavily epigenetically-regulated genes. In the present work we induced an 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 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 theexpression of DNMT1 and DNMT3a at 7- and 21-DPSE. 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