SSa ameliorates the Glu uptaking capacity of astrocytes in epilepsy via AP-1 /miR-155/GLAST

Background: Neuronal glutamate(Glu) release has been reported to mediate the neuronal injury of epilepsy, while Saikosaponin a (Ssa) was shown to ameliorate the epilepsy that induced by pentylenetetrazol (PIL). However, potential interactions between glutamate release and Ssa has not been fully identified. Methods: Herein, PTZ-induced rat model were established to evaluate the neuron injury, while Ssa was used to treat the model rat. Rat astrocytes were isolated and induced by PTZ to construct cell models of epilepsy, real-time PCR and western blot were used to determine genes' expression. Luciferase reporter assay were performed to validate the relationship between miR-155-5p and glutamate aspartate transporter (GLAST). The level of Glu was sampled for HPLC measurement. Results: Ssa treatment could decrease the level of Glu in hippocampus of rat. PTZ-induced astrocytes pretreated with Ssa significantly decreased the expression of AP-1 and miR-155, but increased the expression of GLAST, furthermore, PIL stimulation enables astrocytes to uptake large amount of extra cellular Glu. AP-1 could bind with the promoter of miR-155 to promote its transcription. MiR-155 tragets GLAST to govern its expression. Conclusion: Ssa treatment played pivotal roles in PTZ-induced epilepsy by promoting the expression of GLAT1 and uptaking of Glu, which was mediated by the expression of AP-1 and miR-155. (C) 2017 Published by Elsevier Inc.