Inhibition of MicroRNA-383 Ameliorates Injury After Focal Cerebral Ischemia via Targeting PPARγ.
BACKGROUND
Peroxisome proliferator-activated receptor gamma (PPARγ) plays a critical role in protecting against distinct brain damages, including ischemia. Our previous data have shown that the protein level of PPARγ is increased in the cortex after middle cerebral artery occlusion (MCAO); PPARγ up-regulation contributes to PPARγ activation and is effective in reducing ischemic damage to brain. However, the regulatory mechanism of PPARγ after focal cerebral ischemia in rats is still unclear. In this study, we evaluated the effect of microRNA on PPARγ in rats subjected to MCAO.


METHODS
Focal cerebral ischemia was established by surgical middle cerebral artery occlusion; the protein level of PPARγ 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 PPARγ 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 PPARγ 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 PPARγ, whereas mutation of the binding sites relived the repressive effect of miR-383.


CONCLUSIONS
Our study demonstrated that miR-383 may play a key role in focal cerebral ischemia by regulating PPARγ expression at the post-transcriptional level, and miR-383 may be a potential therapeutic target for stroke.
Department of Geriatrics, The Second affiliated Hospital of Harbin Medical University, Harbin, China.
Lichun
L
Pei
Songyan
S
Meng
Weigang
W
Yu
Qiujun
Q
Wang
Fangfang
F
Song
Lan
L
Ma
D000818:Animals; D000070416:Antagomirs / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002545:Brain Ischemia / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002339:Carotid Arteries / Q000473:pathology / Q000601:surgery; D002540:Cerebral Cortex / Q000378:metabolism* / Q000473:pathology; D054059:Coronary Occlusion / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008297:Male; D035683:MicroRNAs / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D047495:PPAR gamma / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D061251:Primary Cell Culture; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D020521:Stroke / Q000235:genetics* / Q000378:metabolism / Q000473:pathology
D000070416:Antagomirs; C000611600:MIRN383 microRNA, rat; D035683:MicroRNAs; D047495:PPAR gamma; D008156:Luciferases