title: MiRNA-424 protects against permanent focal cerebral ischemia injury in mice involving suppressing microglia activation.
abstract: OBJECTIVE
  We observed that microRNA-424 (miR-424) significantly decreased in an miRNA profile of circulating lymphocytes of patients with ischemic stroke. The present study focused on the potential and mechanism of miR-424 in protecting ischemic brain injury in mice.
  
  
  METHODS
  Cerebral ischemia was induced by middle cerebral artery occlusion in C57/BL6 mice. Cerebral infarction volume, neuronal apoptosis, and microglia activation were determined by 2,3,5-triphenyltetrazolium chloride staining, immunofluorescence, and Western blot. BV2 microglial cell activity, cell cycle, mRNA, and protein levels of miR-424 targets were accessed by enzyme-linked immunosorbent assay, flow cytometry, real-time polymerase chain reaction, and Western blot, respectively.
  
  
  RESULTS
  MiR-424 levels were decreased in the plasma of patients with acute ischemic stroke, as well as in mouse plasma and ipsilateral brain tissue at 4, 8, and 24 hours after ischemia, likewise, in the cortex, hippocampus, and basal ganglia, respectively, after 8-hour ischemia. Interestingly, pre- and post-treatment with overexpression of miR-424 both decreased cerebral infarction size and brain edema after middle cerebral artery occlusion. Meanwhile, lentiviral overexpression of miR-424 inhibited neuronal apoptosis and microglia activation, including suppressing ionized calcium binding adaptor molecule-1 immunoreactivity and protein level, and reduced tumor necrosis factor-α production. In vitro study demonstrated that miR-424 mimics caused G1 phase cell-cycle arrest, inhibited BV2 microglia activity, and reduced the mRNA and protein levels of CDC25A, cyclin D1, and CDK6 in BV2 microglial cells, which were upregulated in brain of middle cerebral artery occlusion mice.
  
  
  CONCLUSIONS
  MiR-424 overexpression lessened the ischemic brain injury through suppressing microglia activation by translational depression of key activators of G1/S transition, suggesting a novel miR-based intervention strategy for stroke.
authors.affiliation: Cerebrovascular Diseases Research Institute, Xuanwu Hospital of Capital Medical University, 45 Changchun St, Beijing 100053, People's Republic of China.
authors.forename: Haiping
authors.initials: H
authors.lastname: Zhao
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Gao
authors.forename: Rongliang
authors.initials: R
authors.lastname: Wang
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Liu
authors.forename: Zhi
authors.initials: Z
authors.lastname: Gao
authors.forename: Zhen
authors.initials: Z
authors.lastname: Tao
authors.forename: Changmin
authors.initials: C
authors.lastname: Xu
authors.forename: Juexian
authors.initials: J
authors.lastname: Song
authors.forename: Xunming
authors.initials: X
authors.lastname: Ji
authors.forename: Yumin
authors.initials: Y
authors.lastname: Luo
mesh_terms: D000368:Aged; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002545:Brain Ischemia / Q000378:metabolism / Q000473:pathology* / Q000517:prevention & control*; D016022:Case-Control Studies; D002453:Cell Cycle / Q000502:physiology*; D002478:Cells, Cultured; D004195:Disease Models, Animal; D006801:Humans; D066298:In Vitro Techniques; D020244:Infarction, Middle Cerebral Artery / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D007276:Injections, Intraventricular; D016086:Lentivirus / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D017628:Microglia / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged
chemical_list: C583176:MIRN424 microRNA, mouse; C554214:MIRN424 microrna, human; D035683:MicroRNAs
keywords: brain ischemia; cell cycle; miR-424; microglia