title: Activation of formyl peptide receptor-1 enhances restitution of human retinal pigment epithelial cell monolayer under electric fields.
abstract: OBJECTIVE
  This study aimed at identifying the expression of functional formyl peptide receptor (FPR)-1 in human retinal pigment epithelium (hRPE) cells and to evaluate the role of FPR in regulation of wound closure of the hRPE monolayer under electric fields (EFs).
  
  
  METHODS
  The expression of FPR in hRPE cells was analyzed with an immunofluoresence labeling assay and RT-PCR. Cultured wounded hRPE monolayers were exposed to EFs with free serum, 20%, serum, and a classical FPR agonist, N-formyl-Met-Leu-Phe (fMLF), respectively, for 3 hours. Cell monolayer migrations were traced using an image analyzer. Expressions of cell junction molecules were measured by RT-PCR, and the ultrastructure of cell junctions was observed with transmission electron microscopy (TEM).
  
  
  RESULTS
  The expression of functional FPR was observed and localized along actin filaments in cellular lamellipodia and filopodia. EFs and fMLF significantly increased the migration rates of the wounded RPE monolayer. The migrating distances of monolayers were 24.262 ± 6.82 μm, 40.243 ± 5.069 μm, and 56.926 ± 7.821 μm in cells with free serum, 20% serum, and fMLF under EFs at 3 hours, respectively (P < 0.01). The mRNA expressions of connexin 43(Cx43) and zonula occludens (ZO)-1 were detected in hRPE cells. TEM revealed that cell junctions formed between hRPE cells in the monolayer.
  
  
  CONCLUSIONS
  These results showed for the first time that functional FPR expresses in hRPE cells and that activation of FPR enhances migration of the wounded hRPE monolayer. The mRNA expressions and ultrastructures of cell junctions further demonstrated the RPE sheet as a monolayer migrating under EFs.
authors.affiliation: Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
authors.forename: Xiao-Guang
authors.initials: XG
authors.lastname: Zhang
authors.forename: Yan-Nian
authors.initials: YN
authors.lastname: Hui
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Huang
authors.forename: Hong-Jun
authors.initials: HJ
authors.lastname: Du
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.forename: Ji-Xian
authors.initials: JX
authors.lastname: Ma
mesh_terms: D000199:Actins / Q000378:metabolism; D015820:Cadherins / Q000235:genetics; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D018031:Connexin 43 / Q000235:genetics; D004574:Electromagnetic Fields; D019084:Fluorescent Antibody Technique, Indirect; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics; D046529:Microscopy, Electron, Transmission; D010750:Phosphoproteins / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D044042:Receptors, Formyl Peptide / Q000235:genetics / Q000378:metabolism*; D055213:Retinal Pigment Epithelium / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014019:Tissue Donors; D014945:Wound Healing / Q000502:physiology*; D062826:Zonula Occludens-1 Protein
chemical_list: D000199:Actins; D015820:Cadherins; D018031:Connexin 43; C469986:FPR1 protein, human; C500216:GJA1 protein, human; D008565:Membrane Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D044042:Receptors, Formyl Peptide; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein