miR-21, a potential therapeutic target of alleviating blood-brain barrier damage after traumatic brain injury

Traumatic brain injury (TBI) is a disease with high morbidity and leads to high rate of disability and mortality. The blood-brain barrier (BBB) damage is an important pathological change in brain after TBI, which impacts the development and prognosis of the disease. In our previous research, we have reported that miR-21-5p in neurons can exert an anti-apoptosis effect, and promote the restoration of injured BBB after TBI. Up-regulation of miR-21-5p level in brain can amplify the above functions of miR-21-5p, thus alleviate BBB damage and improve the prognosis of TBI. miR-21-3p, which is generated from pre-miR-21 at the same time with miR-21-5p, has been reported to play significant roles in regulating the expression of angiogenic factors, which can impact downstream immuno-inflammatory responses and cellular apoptosis. We made a summary of previous reports on miR-21-3p and inferred that miR-21-3p could influence the development of BBB damage after TBI. Taken together, miR-21 is a vital miRNA that impacts the restoration of traumatic BBB damage, thus it could be a potential therapeutic target for interventions in TBI.