Identifying the differentially expressed circRNAs and mRNAs in the subacute stage of spinal cord injury in mice by RNA-sequencing

Spinal cord injury (SCI) is a pathological condition that leading to serious nerve damage?disability and even death. Some scholars have divided the pathophysiology of SCI into primary mechanism and secondary mechanism. Secondary SCI can be divided into acute, subacute, and chronic stages, with the subacute stage lasting 2 days to 2 weeks after SCI. The subacute stage of SCI is a potentially critical time point for further study of SCI repair, which may play a significant role in the secondary SCI. Increasing evidence have revealed that circular RNAs (circRNAs) and mRNA are widely involved in the regulation of the pathological process of neurological diseases by sponging microRNAs (miRNAs). Nevertheless, the potential biological functions and regulatory mechanisms of circRNAs in the subacute stage of SCI remain unclear. We analyzed the expression and regulatory patterns of circRNAs and mRNAs in SCI mice models using RNA-sequencing. A total of 24 circRNAs and 372 mRNAs were identified to be differentially expressed, and found that circRNA02778, circRNA02370, and Ctsd were top up-regulated as well as circRNA05219 and Huwe1 were top down-regulated after SCI. Meanwhile, we identified multiple immune-related genes (Ptprc, Fcgr2b, Ccl2, Tlr7, Cxcl10, Cd28, Il10ra, Cd68, and Tlr3) related to SCI and found they were significantly upregulated after SCI, but the specific mechanisms by which they regulate SCI by mediating neuronal inflammatory and immune responses need to be further explored. These findings will contribute to elucidate the pathophysiology of SCI and provide effective therapeutic targets for SCI patients. Overall design: CircRNAs and mRNAs expression profiling analysis of RNA-sequencing data generated from six C57BL/6 male mice samples under two conditions: control (n = 3), and spinal cord injury (n = 3). Three control mice underwent a laminectomy at the T10 level without injury to the spinal cord, the other three experimental mice were placed on the NYU IMPACTOR MODEL-II spinal cord hitter platform after laminectomy at the T10 level, and the T10 spinal cord was hit with a hitting head weighing 10 grams to construct a SCI model. All the six mice were killed on the 4th day after surgery, and the spinal cord tissue about 4 cm long around the T10 level were collected for high-throughput RNA-sequencing.