title: [Effects of magnetic field on MAPK signaling pathways of human retinal pigment epithelial cells bound with beads in vitro].
abstract: OBJECTIVE
  To observe the changes of mitogen activated protein kinase (MAPK) signaling pathways of human retinal pigment epithelial cells( RPEs) bound with beads under stretch caused by the force from magnetic field in vitro.
  
  
  METHODS
  Ferric oxide microparticles, coAted with collagen, were added to dishes containing substrate-attached RPEs. After incubation, the cell layer bound with beads was laid in a magnetic field, the cells were stretched by the magnetic force. The activation status of the extracellular signal-regulated protein kinase (ERK), c-jun N-terminal kinase (JNK), and p38 in RPEs was determined over a time course from 3 to 30 minutes with western-blot analysis. To examine the role of p38 kinase in the response to stretching, cells were grown for 30 minutes in the presence or absence of inhibitor of p38 (SB203580). The changes of the expression of active p38 kinase were observed with fluorescence staining.
  
  
  RESULTS
  Total ERK, JNK, and p38 were detected in RPEs. Active ERK and p38 were detected but active JNK was not detected. Activation of ERK was unchanged during the time course. In contrast, p38 activation was barely detected in the normal cells, but this stress-activated protein kinase exhibited a robust activation after 5 minutes in the magnetic field. SB203580 blocked the p38 activation during stretch stimulation. The stretch stimulation also increased the fluorescence staining of active p38.
  
  
  CONCLUSIONS
  A magnetic field can affect RPEs bound with beads. The effect may be partially through p38 signaling pathway.
authors.affiliation: Institute of Ophthalmology, Xijing Hospital, the Fourth Military Medical University, Xi' an, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Hou
authors.forename: Yan-nian
authors.initials: YN
authors.lastname: Hui
authors.forename: Quan-hong
authors.initials: QH
authors.lastname: Han
authors.forename: Xiao-guang
authors.initials: XG
authors.lastname: Zhang
authors.forename: Dan
authors.initials: D
authors.lastname: Hu
authors.forename: Chang-mei
authors.initials: CM
authors.lastname: Guo
mesh_terms: D002478:Cells, Cultured; D004574:Electromagnetic Fields; D004847:Epithelial Cells / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects*; D015398:Signal Transduction; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases