Inhibition of MicroRNA-383 Ameliorates Injury After Focal Cerebral Ischemia via Targeting PPARγ

Background: Peroxisome proliferator-activated receptor gamma (PPAR.) plays a critical role in protecting against distinct brain damages, including ischemia. Our previous data have shown that the protein level of PPAR. is increased in the cortex after middle cerebral artery occlusion (MCAO); PPAR gamma up-regulation contributes to PPAR. activation and is effective in reducing ischemic damage to brain. However, the regulatory mechanism of PPAR. after focal cerebral ischemia in rats is still unclear. In this study, we evaluated the effect of microRNA on PPAR. in rats subjected to MCAO. Methods: Focal cerebral ischemia was established by surgical middle cerebral artery occlusion; the protein level of PPAR. was detected by Western blotting; the level of microRNA-383 (miR-383) was quantified by real-time PCR; the neurological outcomes were defined by infarct volume and neurological deficits. Luciferase assay was used to identify the luciferase activities of PPAR. and miR-383. Results: We showed here that miR-383 level was down-regulated in the ischemic hemisphere of rats 24h after MCAO. Overexpression of miR-383 by miR-383 agomir increased infarct volume and aggravated neurological damage. Administration of miR-383 antagomir had the opposite effects. Furthermore, we found that PPAR. protein was down-regulated by miR-383 overexpression, and up-regulated by miR-383 inhibition both in rat model of MCAO and in primary culture cells. Finally, we found that miR-383 suppressed the luciferase activity of the vector carrying the 3'UTR of PPAR., whereas mutation of the binding sites relived the repressive effect of miR-383. Conclusion: Our study demonstrated that miR-383 may play a key role in focal cerebral ischemia by regulating PPAR. expression at the post-transcriptional level, and miR-383 may be a potential therapeutic target for stroke. (C) 2016 The Author(s) Published by S. Karger AG, Basel