MicroRNA expression profiles in chronic epilepsy rats and neuroprotection from seizures by targeting miR-344a.

MicroRNA (miRNA) is believed to play a crucial role in the cause and treatment of epilepsy by controlling gene expression. However, it is still unclear how miRNA profiles change after multiple prolonged seizures and aggravation of brain injury in chronic epilepsy (CE). To investigate the role of miRNA in epilepsy, we utilized the CE rat models with pentylenetetrazol (PTZ) and miRNA profiles in the hippocampus. miRNA profiles were characterized using miRNA microarray analysis and were compared with the rats in the sham group, which received 0.9% physiological saline treatment at the same dose. Four up-regulated miRNAs (miR-139-3p, -770-5p, -127-5p, -331-3p) and 5 down-regulated miRNAs (miR-802-5p, -380-5p, -183-5p, -547-5p, -344a/-344a-5p) were found in the CE rats (fold change >1.5, <0.05). Three of the dysregulated miRNAs were validated by quantitative real-time polymerase chain reaction, which revealed an outcome consistent with the initial results of the miRNA microarray analyses. Then, miR-344a agomir was intracerebroventricularly injected and followed by PTZ induction of CE models to investigate the effect of miR-344a in chronic neocortical epileptogenesis. After miRNA-344a agomir and scramble treatment, results showed a restoration of seizure behavior and a reduction in neuron damage in the cortex in miRNA-334a agomir treated rats. These data suggest that miRNA-344a might have a small modulatory effect on seizure-induced apoptosis signaling pathways in the cortex.