title: MicroRNA-124-mediated regulation of inhibitory member of apoptosis-stimulating protein of p53 family in experimental stroke.
abstract: OBJECTIVE
  p53-mediated neuronal death is a central pathway of stroke pathophysiology, but its mechanistic details remain unclear. Here, we identified a novel microRNA mechanism that downregulation of inhibitory member of the apoptosis-stimulating proteins of p53 family (iASPP) by the brain-specific microRNA-124 (miR-124) promotes neuronal death after cerebral ischemia.
  
  
  METHODS
  In a mouse model of focal permanent cerebral ischemia, the expression of iASPP and miR-124 was quantified by reverse transcription quantitative real-time polymerase chain reaction, immunofluorescence staining, and Western blot. Luciferase reporter assay was used to validate whether miR-124 can directly bind to the 3'-untranslated region of iASPP mRNA. To evaluate the role of miR-124, miR-124 mimic and its inhibitor were transfected into Neuro-2a cells and C57 mice.
  
  
  RESULTS
  There was no change in the iASPP mRNA level in cerebral ischemia. However, iASPP protein was remarkably decreased, with a concurrent elevation in miR-124 level. Furthermore, miR-124 can bind to the 3'-untranslated region of iASPP in 293T cells and downregulate its protein levels in Neuro-2a cells. In vivo, infusion of miR-124 decreased brain levels of iASPP, whereas inhibition of miR-124 enhanced iASPP levels and significantly reduced infarction in mouse focal cerebral ischemia.
  
  
  CONCLUSIONS
  These data demonstrate that p53-mediated neuronal cell death after stroke can be nontranscriptionally regulated by a novel mechanism involving suppression of endogenous cell death inhibitors by miR-124. Further dissection of microRNA regulatory mechanisms may lead to new therapeutic opportunities for preventing neuronal death after stroke.
authors.affiliation: Cerebrovascular Diseases Research Institute, Xuanwu Hospital of Capital Medical University, Key Laboratory of Neurodegenerative Diseases (Capital Medical University), Ministry of Education, Beijing, China.
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Liu
authors.forename: Fang
authors.initials: F
authors.lastname: Li
authors.forename: Shangfeng
authors.initials: S
authors.lastname: Zhao
authors.forename: Yumin
authors.initials: Y
authors.lastname: Luo
authors.forename: Jun
authors.initials: J
authors.lastname: Kang
authors.forename: Haiping
authors.initials: H
authors.lastname: Zhao
authors.forename: Feng
authors.initials: F
authors.lastname: Yan
authors.forename: Sijie
authors.initials: S
authors.lastname: Li
authors.forename: Xunming
authors.initials: X
authors.lastname: Ji
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism*; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000502:physiology*; D011897:Random Allocation; D012097:Repressor Proteins / Q000378:metabolism*; D020521:Stroke / Q000378:metabolism*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D035683:MicroRNAs; C540079:Mirn124 microRNA, mouse; C406964:Perp protein, mouse; C501916:Ppp1r13l protein, mouse; D012097:Repressor Proteins
keywords: ASPP; apoptosis; cerebral ischemia; iASPP; microRNAs