microRNA s (9, 138, 181A, 221, and 222) and mesial temporal lobe epilepsy in developing brains

Background: Recently, microRNAs (miRNAs) have attracted much attention as novel players in the pathogenesis of mesial temporal lobe epilepsy (MTLE) in mature and developing brains. This study aimed to investigate the expression dynamics of miR-9, miR-138, miR-181a, miR-221, and miR-222 in the hippocampus of an immature rat model during the three stages of MTLE development and in children with MTLE. Methodology: qPCR was used to measure expression levels during the three stages of MTLE development (2 h, 3, and 8 weeks after induction of lithium-pilocarpine status epilepticus, representing the acute, latent, and chronic stages, respectively. Expression levels were also measured in hippocampi obtained from children with MTLE and normal controls. Results: In the rat model, miR-9 was significantly upregulated during the acute and chronic stages relative to controls, but not during the latent stage. MiR-138, miR-221 and miR-222 were all downregulated during all three stages of MTLE development. MiR-181a was downregulated during the acute stage, upregulated during the chronic stage, and unaltered during the latent stage. In children, miR-9 and miR-181a were upregulated, while miR-138, miR-221, and miR-222 were downregulated. Conclusion: Modulation of these miRNAs may be a new strategy in designing antiepileptic and anticonvulsant therapies for the developing brain.