Therapeutic Target MicroRNA Identification Based on Circular RNA Expression Signature After Intracerebral Hemorrhage

We investigated circular RNA (circRNA) expression pattern from a rat intracerebral hemorrhage (ICH) model and tested therapeutic strategy. Hemorrhagic stroke was induced by stereotactic collagenase injection. Brain was harvested at 1, 3, and 7 days after ICH induction to study circRNA expression. Significantly altered circRNAs from microarray were examined by quantitative real-time polymerase chain reaction. Predicted target microRNA and nearby messenger RNA levels of significantly altered circRNAs were validated from previously published database. Therapeutic strategy based on potential target microRNA of significantly depressed circRNA was examined using in vitro and in vivo hemorrhagic model. Both significantly elevated/downregulated circRNA increased as time passed after ICH: 9, 159, and 704 circRNAs were significantly elevated, whereas 19, 276, and 656 circRNAs were significantly depressed at 1, 3 and 7 days after ICH induction, respectively, out of 13,298 studied circRNAs. The most elevated circRNAs were rno_circRNA_002714 and rno_circRNA_002715, which are located closely each other in chromosome 10, within exon sequence of glial fibrillary acidic protein. The most significantly downregulated circRNA was rno_circRNA_016465, which has several complementary sequences for miR-466b. The most commonly predicted microRNA response element of significantly depressed circRNAs was miR-466b. The antagonistic sequence against miR-466b significantly decreased neuronal cell death and improved neurological recovery in a hemorrhagic stroke model by upregulating insulin like growth factor receptors 1 and 2. This study illustrated dynamic circRNA expression pattern in a hemorrhagic stroke model, which correlated with microRNA and messenger RNA expression, suggesting the regulatory role of RNA dynamics in ICH.