The Role of MicroRNA in Traumatic Brain Injury

Traumatic brain injury (TBI) is a public health problem that causes high mortality and disability worldwide. Secondary brain damage from this type of injury may cause brain edema, blood-brain barrier destruction, and neurological dysfunction. MicroRNAs (miRNAs) are a class of small non-coding RNAs that regulate gene expression at the post-transcriptional level and play vital roles in maintaining and regulating physiological function. Notably, studies suggest that miRNA levels are altered in the cerebral cortex and hippocampus of rats and mice after TBI. These miRNAs exhibit promoting or inhibiting effects on the formation of secondary brain damage, such as promotion of neuron regeneration and apoptosis, alleviation of leakage across the blood-brain barrier (BBB), disruption of intracellular transport, and decreasing the inflammatory response. miRNA levels are also altered in the blood and cerebral spinal fluid (CSF) of humans with TBI. Some special miRNAs in blood were used in clinical trials for TBI diagnosis and prognosis prediction. Treatment with miRNA agomirs or antagomirs alleviated the lesion volume and improved neurological deficits post-injury. We review the current progress of miRNA studies in TBI patients and animal models and identify the prospects and difficulties involved in the clinical applications of miRNAs.