Role of Circular RNAs in Traumatic Brain Injury and Spinal Cord Injury.

Circular RNAs (circRNAs) are a unique class of noncoding RNAs that are formed post-transcriptionally, unlike all other classes of ncRNAs that are transcribed from the genome. They are the only class of RNAs that are closed loops with no 5' and 3' ends. Recent studies showed that mammals form >100,000 unique circRNAs that contain only exons, only introns, or both exons and introns. circRNAs are formed and degraded by various mechanisms, which are specific to this class of RNAs. This review article discusses the functional significance of circRNAs in the pathophysiology of traumatic brain injury and spinal cord injury, with an emphasis on their functionality in controlling mechanisms such as inflammation, oxidative stress, apoptosis, autophagy, neuronal plasticity, neuroprotection, and functional recovery, which are all important for outcomes after an acute central nervous system injury.