MicroRNA-15a/16-1 antagomir ameliorates ischemic brain injury in experimental stroke

Abstract

Background and Purpose

Dysregulation of the miR-15a/16-1 cluster in plasma has been reported in stroke patients as a potential biomarker for diagnostic and prognostic use. However, the essential role and therapeutic potential of the miR-15a/16-1 cluster in ischemic stroke are poorly understood. This study is aimed at investigating the regulatory role of the miR-15a/16-1 cluster in ischemic brain injury and insight mechanisms.

Methods

Adult male miR-15a/16-1 knockout and wild-type mice, or adult male C57 BL/6J mice injected via tail vein with the miR-15a/16-1 specific inhibitor (antagomir, 30 pmol/g), were subjected to 1h of middle cerebral artery occlusion (MCAO) and 72h of reperfusion. The neurological scores, brain infarct volume, brain water content, and neurobehavioral tests were then evaluated and analyzed. To explore underlying signaling pathways associated with alteration of miR-15a/16-1 activity, major pro-inflammatory cytokines were measured by qPCR or ELISA and anti-apoptotic proteins were examined by western blotting.

Results

Genetic deletion of the miR-15a/16-1 cluster or intravenous delivery of miR-15a/16-1 antagomir significantly reduced cerebral infarct size, decreased brain water content and improved neurological outcomes in stroke mice. Inhibition of miR-15a/16-1 significantly decreased the expression of the pro-inflammatory cytokines IL-6, MCP-1, VCAM-1 and TNF-α, and increased Bcl-2 and Bcl-w levels in the ischemic brain regions.

Conclusions

Our data indicate that pharmacological inhibition of the miR-15a/16-1 cluster reduces ischemic brain injury via both upregulation of anti-apoptotic proteins and suppression of pro-inflammatory molecules. These results suggest that the miR-15a/16-1 cluster is a novel therapeutic target for ischemic stroke.