Identification of differentially expressed circRNAs in human temporal lobe epilepsy with hippocampal sclerosis ILAE type 1

Hippocampal sclerosis (HS) is the most common surgical pathology associated with temporal lobe epilepsy (TLE). However, the cause of TLE with or without HS remains unknown. Our current study aimed to illustrate the essential molecular mechanism that is potentially involved in the pathogenesis of TLE-HS and to shed light on the transcriptional changes associated with hippocampal sclerosis. Circular RNAs (circRNAs) are a novel class of non-coding RNA and stably conserved in mammalian brain tissues. However, the circRNA expression profile of HS ILAE type 1 is not completely understood. A total of 14 patients were identified as having the ILAE subtype, as determined by NeuN immunohistochemistry (ILAE type 1=7; no-HS=7). Next-generation sequencing and reverse transcription polymerase chain reaction technology was used to validate the selected circRNAs. In total, 133 circRNA transcripts were detected in this study, along with 96 circRNAs were upregulated and 37 circRNAs were downregulated expression in the type 1 group. A circRNA-mRNA co-expression network was constructed including 5 circRNAs(hsa_circ_0025349, hsa_circ_0002405, hsa_circ_0004805, hsa_circ_0032254, and hsa_circ_0032875) and three mRNAs (FYN, SELENBP1, and GRIPAP1) based on the normalized mRNA signal intensities. These results provide new insights into the neuron loss pathology and offer fundamental evidence as to why there is a good prognosis among patients with type 1 HS.