Downregulation of circ_008018 protects against cerebral ischemia-reperfusion injury by targeting miR-99a.

Circular RNAs (circRNAs) are highly expressed in eukaryotic cells and regulate physiological and pathophysiological processes. However, the role of circRNAs in cerebral ischemia–reperfusion (I/R) injury remains largely unknown. In this study, we found that circ_008018 level was higher in the cortical tissue of mice with middle cerebral artery occlusion as compared to those in the sham group 24 h after reperfusion. Knockdown of circ_008018 attenuated cerebral I/R-induced brain tissue damage and neurological deficits in mice by inducing microRNA miR-99a overexpression. The decreased phosphorylation of Akt and glycogen synthase kinase 3β caused by I/R was partly reversed by circ_008018 silencing or miR-99a overexpression. Taken together, these results provide new insight into the mechanisms of apoptosis resulting from cerebral I/R injury and suggest that targeted inhibition of circ_008018 can protect against subsequent neurological damage.