H-Index
79
Scimago Lab
powered by Scopus
JCR
Clarivate
Analytics
15%
Acceptance
Rate
call: +1.631.470.9640
Mon-Fri 10 am - 2 pm EST

Logo

Medical Science Monitor Basic Research
AmJCaseRep

Annals
ISI-Home

eISSN: 1643-3750

Influence of miR-155 on Cell Apoptosis in Rats with Ischemic Stroke: Role of the Ras Homolog Enriched in Brain (Rheb)/mTOR Pathway

Guoping Xing, Zengxiang Luo, Chi Zhong, Xudong Pan, Xiaowei Xu

Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China (mainland)

Med Sci Monit 2016; 22:5141-5153

DOI: 10.12659/MSM.898980

Available online:

Published: 2016-12-27


#898980

BACKGROUND: We designed and carried out this study to examine the role of miR-155 and the Rheb/mTOR pathway in ischemic stroke. We also investigated how these two elements interact with each other and contribute to injuries resulting from ischemic stroke.
MATERIAL AND METHODS: We used both a middle cerebral artery occlusion rat model in vivo and an oxygen-glucose deprivation cell model in vitro to simulate the onset of ischemic stroke. miR-155 mimics, miR-155 inhibitors, and Rheb siRNA were transfected to alter the expression of miR-155 and Rheb. Infarct sizes were measured using magnetic resonance imaging (MRI) and triphenyltetrazolium chloride (TTC) staining; cell apoptosis rates were calculated using Annexin V-FITC/PI staining and flow cytometry. Levels of miR-155, Rheb, mTOR, and S6K were examined by RT-PCR, immunofluorescence, and western blot. We performed a luciferase activity assay so that the association between miR-155 and Rheb could be fully assessed.
RESULTS: We demonstrated that miR-155 bound the 3’-UTR of Rheb and suppressed Rheb expression. As suggested by animal models, significant cerebral infarct volumes and cell apoptosis were induced by increased expression of miR-155 and decreased expression of Rheb, mTOR, and p-S6K (P<0.05). miR-155 inhibitors exhibited protective effects on ischemic stroke, including down-regulation of infarction size in cerebral tissues in vivo and reduced apoptosis of BV2 cells in vitro with increased expression of Rheb, mTOR and p-S6K (P<0.05). These protective effects could be substantially antagonized by the transfection of Rheb siRNA (P<0.05).
CONCLUSIONS: Inhibition of miR-155 may play protective roles in ischemic stroke by phosphorylating S6K through the Rheb/mTOR pathway.

Keywords: Infarction, Middle Cerebral Artery, Stroke, TOR Serine-Threonine Kinases



Back