Expression Profiles Of CircRNAs And MRNAs In Early Brain Injury Following Experimental Subarachnoid Hemorrhage

Background and objective:Subarachnoid hemorrhage?SAH?is a fatal neurovascular disease with high rates of disability and mortality.CircRNAs are extraordinarily enriched in the mammalian brain,well conserved in sequence and involved in many nervous system diseases.This study aims to detect the expression profiles of circRNAs and mRNAs in SAH brain tissue of mice by high-throughput sequencing.To explore possible biological functions of circRNAs in early brain injury?EBI?.To lay the foundation theory for the further studies on biomarkers and the investigation of regulatory mechanism of differentially expressed circRNAs following SAH.Methods:A total of 18 C57BL/6J male mice were randomly divided into control and SAH group?n=9 for each group?.SAH models were induced by endovascular perforation,twenty-four hours after operation,total RNAs of brain samples were extracted to construct the cDNA library.RNA-sequencing?RNA-seq?was carried out by Illumina HiSeq^TM2500 and followed by qRT-PCR for confirmation.Reads were aligned to the mouse transcriptome with Bowite2 to obtain expression profiles of circRNAs and mRNAs.Bioinformatics analysis for significantly differentially expressed circRNAs and mRNAs include GO analysis,KEGG pathway analysis,forecast targeted miRNAs of circRNAs and construction circRNA-miRNA-mRNA network.Results:A total of 26 circRNA transcripts?6 upregulated and 20 downregulated?and804 mRNA transcripts?396 upregulated and 408 downregulated?were significantly aberrantly expressed after SAH.Bioinformatics predicted that these26 circRNAs contain binding sites for many miRNAs.Gene ontology?GO?enrichment and Kyoto Encyclopedia of Genes and genomes?KEGG?analysis predicted that these differentially expressed mRNAs were mainly related to inflammatory and immune response,protein binding and extracellular region.In SAH model,GO and KEGG showed that most mRNAs originated from the parent genes of these circRNAs are involved in phosphorylation,protein binding and axon guidance.qRT-PCR analysis of 5 randomly selected circRNAs confirmed the accuracy of RNA-seq?circFoxj3,circSetbp1 and circ Sntg2 were up-regulated,while circArpp21 and circ2010111I01Rik were down-regulated?.Conclusion:CircRNAs and mRNAs were significantly differentially expressed between the SAH group and the control group of mice brain tissues.Differentially expressed circRNAs and mRNAs may be involved in various biological process including inflammatory and immune response,protein binding and axon guidance.CircRNAs may be a promising potential therapeutic target for the diagnosis,treatment and prognosis of SAH.To lay a foundation for further study on mechanism of circRNA in EBI following SAH.