title: Fibroblast growth factor-peptide improves barrier function and proliferation in human keratinocytes after radiation.
abstract: OBJECTIVE
  Epidermal keratinocytes, which can be severely damaged after ionizing radiation (IR), are rapid turnover cells that function as a barrier, protecting the host from pathogenic invasion and fluid loss. We tested fibroblast growth factor-peptide (FGF-P), a small peptide derived from the receptor-binding domain of FGF-2, as a potential mitigator of radiation effects via proliferation and the barrier function of keratinocytes.
  
  
  METHODS
  Keratinocytes isolated from neonatal foreskin were grown on transwells. After being exposed to 0, 5, or 10 Gy IR, the cells were treated with a vehicle or FGF-P. The permeability of IR cells was assessed by using transepithelial electrical resistance (TEER) and a paracellular tracer flux of fluorescein isothiocyanate-conjugated bovine serum albumin (FITC-BSA) with Ussing chambers. The cell proliferation was measured with yellow tetrazolium salt (MTT) and tritiated thymidine ([3H]-TdR) assays. The phosphorylation of extracellular signal-regulated kinases (ERK) was measured in an enzyme-linked immunosorbent (ELISA)-like assay, and the proteins related to tight junctions (TJ) and adherens junctions (AJ) were examined with Western blotting. We used a mouse model to assess the ability of FGF-P to promote the healing of skin β burns created with a strontium applicator.
  
  
  RESULTS
  We found (1) FGF-P reduced the permeability of irradiated keratinocytes, as evidenced by increased TEER and decreased diffusion of FITC-BSA, both associated with the regulation of different proteins and levels of TJ and AJ; and (2) FGF-P enhanced the proliferation of irradiated keratinocytes, as evidenced by increased MTT activity and [3H]-TdR incorporation, which was associated with activation of the ERK pathway; and (3) FGF-P promoted the healing of skin β burns.
  
  
  CONCLUSIONS
  FGF-P enhances the barrier function, including up-regulation of TJ proteins, increases proliferation of human keratinocytes, and accelerates the healing of skin β burns. FGF-P is a promising mitigator that improves the proliferation and barrier function of keratinocytes after IR.
authors.affiliation: Department of Radiation Oncology, University of Rochester Medical Center, Rochester, New York 14642, USA.
authors.forename: Kunzhong
authors.initials: K
authors.lastname: Zhang
authors.forename: Yeping
authors.initials: Y
authors.lastname: Tian
authors.forename: Liangjie
authors.initials: L
authors.lastname: Yin
authors.forename: Mei
authors.initials: M
authors.lastname: Zhang
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Beck
authors.forename: Bingrong
authors.initials: B
authors.lastname: Zhang
authors.forename: Paul
authors.initials: P
authors.lastname: Okunieff
authors.forename: Lurong
authors.initials: L
authors.lastname: Zhang
authors.forename: Sadasivan
authors.initials: S
authors.lastname: Vidyasagar
mesh_terms: D000818:Animals; D002455:Cell Division; D002463:Cell Membrane Permeability / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D049109:Cell Proliferation; D004353:Drug Evaluation, Preclinical / Q000379:methods; D017097:Electric Impedance; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D008297:Male; D008565:Membrane Proteins / Q000032:analysis; D051379:Mice; D008807:Mice, Inbred BALB C; D010446:Peptide Fragments / Q000494:pharmacology*; D010766:Phosphorylation; D011833:Radiation Injuries, Experimental / Q000188:drug therapy; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D011897:Random Allocation; D012709:Serum Albumin / Q000493:pharmacokinetics; D019108:Tight Junctions / Q000378:metabolism; D014945:Wound Healing / Q000187:drug effects
chemical_list: C548915:FGF-P peptide; C518288:FITC-albumin; D008565:Membrane Proteins; D010446:Peptide Fragments; D011837:Radiation-Protective Agents; D012709:Serum Albumin; D016222:Fibroblast Growth Factor 2; D048049:Extracellular Signal-Regulated MAP Kinases; D016650:Fluorescein-5-isothiocyanate