title: Down-regulation of microRNA-223 promotes degranulation via the PI3K/Akt pathway by targeting IGF-1R in mast cells.
abstract: BACKGROUND
  Mast cells play a central role in allergic and inflammatory disorders by inducing degranulation and inflammatory mediator release. Recent reports have shown that miRNAs play an important role in inflammatory response regulation. Therefore, the role of miR-223 in mast cells was investigated.
  
  
  METHODS
  The expression of miR-223 was quantified by quantitative real-time polymerase chain reaction (qRT-PCR) in immunoglobulin E (IgE)-mediated mast cells. After successful miR-223 inhibition by transfection, degranulation was detected in IgE-mediated mast cells. The phosphorylation of IκB-α and Akt were examined using western blotting. NF-κB was tested using electrophoretic mobility shift assay. PI3K-inhibitor (LY294002) was used to investigate whether the PI3K/Akt pathway was essential for mast cell activation. The TargetScan database and a luciferase reporter system were used to identify whether insulin-like growth factor 1 receptor (IGF-1R) is a direct target of miR-223.
  
  
  RESULTS
  MiR-223 expression was up-regulated in IgE-mediated mast cells, whereas its down-regulation promoted mast cell degranulation. Levels of IκB-α and Akt phosphorylation as well as NF-κB were increased in miR-223 inhibitor cells. LY294002 could block the PI3K/Akt signaling pathway and rescue the promotion caused by suppressing miR-223 in mast cells. IGF-1R was identified as a direct target of miR-223.
  
  
  CONCLUSIONS
  These findings suggest that down-regulation of miR-223 promotes degranulation via the PI3K/Akt pathway by targeting IGF-1R in mast cells.
authors: Department of Respiratory Medicine, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing, China.
authors: Quan
authors: Q
authors: Wang
authors: Department of Respiratory Medicine, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing, China.
authors: De-Yu
authors: DY
authors: Zhao
authors: Department of Respiratory Medicine, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing, China.
authors: Hong
authors: H
authors: Xu
authors: Department of Pediatrics, Nanjing Maternal and Child Health Hospital of Nanjing Medical University, Nanjing, China.
authors: Hui
authors: H
authors: Zhou
authors: Department of Respiratory Medicine, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing, China.
authors: Qian-Yuan
authors: QY
authors: Yang
authors: Department of Respiratory Medicine, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing, China.
authors: Feng
authors: F
authors: Liu
authors: Department of Pediatrics, the Frist Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Guo-Ping
authors: GP
authors: Zhou
mesh_terms: D000818:Animals; D015550:Cell Degranulation / Q000187:drug effects; D002460:Cell Line; D002867:Chromones / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects; D007073:Immunoglobulin E / Q000378:metabolism; D008407:Mast Cells / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D035683:MicroRNAs / Q000378:metabolism*; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017526:Receptor, IGF Type 1 / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D015854:Up-Regulation
chemical_list: D002867:Chromones; D035683:MicroRNAs; D009025:Morpholines; D047428:Protein Kinase Inhibitors; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D007073:Immunoglobulin E; D019869:Phosphatidylinositol 3-Kinases; D017526:Receptor, IGF Type 1; D051057:Proto-Oncogene Proteins c-akt