Circular RNA expression profiles alter significantly after intracerebral hemorrhage in rats

Circular RNAs (circRNAs) are a class of covalently closed non-coding RNAs, and aberrant alteration of their expression patterns is studied in numerous diseases. This study aimed to investigate whether intracerebral hemorrhage (ICH) affected circRNA expression profiles in the rat brain. Adult male Sprague-Dawley rats were subjected to intrastriatal injection of autologous artery blood to establish the ICH model. The cerebral cortex around hematoma was collected to perform circRNA microarray at 6 h, 12 h and 24 h. Quantitative reverse transcription-PCR (qRT-PCR) was used to validate the results. Bioinformatic methods were applied to predict ceRNA network and perform enrichment analyses for parent genes at three time points and target mRNAs. 111, 1145, 1751 up-regulated and 47, 732, 1329 down-regulated circRNAs were detected in the cerebral cortex of rats at 6 h, 12 h and 24 h after ICH compared with sham group. Most were from exonic regions. 93 were up-regulated and 20 were down-regulated at all three time points. Microarray results of 3 circRNAs were confirmed via qRT-PCR. GO and KEGG analyses for parent genes showed transition from protein complex assembly, cell-cell adhesion and cAMP signaling pathway at 6 h to intracellular signal transduction, protein phosphorylation and glutamatergic synapse at 12 h and 24 h. A circRNA-miRNA-mRNA network was successfully predicted. Enrichment analyses of targeted mRNAs indicated transcriptional regulations and pathways including Rap1, Ras, MAPK, PI3K-Akt, TNF and Wnt signaling and pathways in cancer. This was the first study to demonstrate that ICH significantly altered the expression of circRNAs with promising targets for therapeutic intervention.