Circ_0003170 aggravates human hippocampal neuron injuries by regulating the mir-421/ccl2 axis in cells models of epilepsy

Abstract

Emerging evidence proposes that circular RNAs (circRNAs) are involved in epilep-togenesis. This study aimed to investigate the role and the function mechanism of circ_0003170 in epilepsy models in vitro. Epilepsy models were established in human hippocampal neurons treated by magnesium-free (Mg2+-free) solution. The expression of circ_003170, miR-421 and C-C motif chemokine ligand 2 (CCL2) was detected by qRT-PCR. The putative interaction between miR-421 and circ_003170 or CCL2 was validated by dual-luciferase reporter assay and RIP assay. The protein level of CCL2 was detected by Western blot. Cell viability was detected by CCK-8 assay, and cell cycle and apoptosis were monitored by flow cytometry. The content of superoxide dismutase (SOD) and malondialdehyde (MDA) and the activity of caspase-3 were assessed using commercial kits. The results showed that circ_0003170 and CCL2 expression was enhanced, while miR-421 expression was declined in temporal lobe epilepsy serum specimens and Mg2+-free-induced neurons. circ_0003170 knockdown ameliorated Mg2+-free-induced cell cycle arrest, oxidative stress and apoptosis in neurons by enriching miR-421. Further analysis presented that miR-421 overexpression alleviated Mg2+-free-induced cell injuries by depleting CCL2. CCL2 overexpression reversed the effects of circ_0003170 knockdown. Overall, circ_0003170 knockdown ameliorated Mg2+-free-induced human hippocampal neuron injuries by mediating the miR-421/CCL2 axis.