title: Secretion Profile of Induced Pluripotent Stem Cell-Derived Retinal Pigment Epithelium During Wound Healing.
abstract: OBJECTIVE
  The purpose of this study was to characterize the secretion profile of induced pluripotent stem cell-derived retinal pigment epithelium (iPS-RPE) during wound healing. iPS-RPE was used to develop an in vitro wound healing model. We hypothesized that iPS-RPE secretes cytokines and growth factors which act in an autocrine manner to promote migration and proliferation of cells during wound healing.
  
  
  METHODS
  iPS-RPE was grown in transwells until fully confluent and pigmented. The monolayers were scratched to induce a wound. Levels of Ki-67, β-catenin, e-cadherin, n-cadherin, and S100A4 expression were analyzed by immunofluorescent labeling. Cell culture medium samples were collected from both the apical and basolateral sides of the transwells every 72 hours for 21 days. The medium samples were analyzed using multiplex ELISA to detect secreted growth factors and cytokines. The effects of conditioned medium on collagen gel contraction, cell proliferation, and migration were measured.
  
  
  RESULTS
  iPS-RPE underwent epithelial-mesenchymal transition (EMT) during wound healing as indicated by the translocation of β-catenin to the nucleus, cadherin switch, and expression of S100A4. GRO, GM-CSF, MCP-1, IL-6, and IL-8 were secreted by both the control and the wounded cell cultures. VEGF, FGF-2, and TGFβ expression were detected at higher levels after wounding than those in control. The proteins were found to be secreted in a polarized manner. The conditioned medium from wounded monolayers promoted collagen gel contraction, as well as proliferation and migration of ARPE 19 cells.
  
  
  CONCLUSIONS
  These results indicate that after the monolayer is wounded, iPS-RPE secretes proteins into the culture medium that promote increased proliferation, contraction, and migration.
authors.affiliation: Ocular Trauma Task Area US Army Institute of Surgical Research, Joint Base San Antonio-Fort Sam Houston, Texas, United States.
authors.forename: Whitney A
authors.initials: WA
authors.lastname: Greene
authors.affiliation: Ocular Trauma Task Area US Army Institute of Surgical Research, Joint Base San Antonio-Fort Sam Houston, Texas, United States.
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Burke
authors.affiliation: Ocular Trauma Task Area US Army Institute of Surgical Research, Joint Base San Antonio-Fort Sam Houston, Texas, United States.
authors.forename: Elaine D
authors.initials: ED
authors.lastname: Por
authors.affiliation: Ocular Trauma Task Area US Army Institute of Surgical Research, Joint Base San Antonio-Fort Sam Houston, Texas, United States.
authors.forename: Ramesh R
authors.initials: RR
authors.lastname: Kaini
authors.affiliation: Ocular Trauma Task Area US Army Institute of Surgical Research, Joint Base San Antonio-Fort Sam Houston, Texas, United States.
authors.forename: Heuy-Ching
authors.initials: HC
authors.lastname: Wang
mesh_terms: D049109:Cell Proliferation; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D058750:Epithelial-Mesenchymal Transition; D005131:Eye Injuries / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D012160:Retina / Q000293:injuries / Q000473:pathology; D055213:Retinal Pigment Epithelium / Q000378:metabolism / Q000473:pathology*; D014945:Wound Healing / Q000502:physiology*
chemical_list: D016207:Cytokines; D036341:Intercellular Signaling Peptides and Proteins