title: Assessment of heat shock protein (HSP60, HSP72, HSP90, and HSC70) expression in cultured limbal stem cells following air lifting.
abstract: OBJECTIVE
  The aim of this study is to create an ex vivo model to examine the expression of major heat-shock protein (HSP) families; HSP60, HSP72, and HSP90, and heat-shock cognate 70 (HCS70) at the mRNA and protein level in differentiating corneal cells from limbal stem cells (LSC) following air exposure.
  
  
  METHODS
  Limbal biopsies taken from cadaveric normal human limbus were cultivated as explants on human amniotic membrane (HAM) and plastic dish (PD). Corneal differentiation was induced by air lifting for 16 days. The expression of putative LSC markers (P63 and ATP-binding cassette G2 [ABCG2]), corneal markers (keratin 3 [K3/12] and connexin 43 [CX43]), and HSP60, HSP72, HSP90, and HSC70 were tested by RT-PCR, immunofluorescence, and flow cytometry pre- and post-air exposure. Fresh limbal and corneal tissues were used as control groups.
  
  
  RESULTS
  Air lifting induced corneal differentiation with a decrease in the number of P63(+) cells and an increase in the number of K3(+)/CX43(+) cells, which characterized transient amplifying cells (TACs). Moreover, denuded HAM provided a superior niche for LSC proliferation and phenotype maintenance in vitro. Additionally, we have evidence that expressions of HSC70 as well as HSP72 were enhanced through corneal differentiation and HSP90 post-air lifting in vitro and in vivo. HSP60, however, was not detected in either LSC or corneal cells, in vivo and in vitro.
  
  
  CONCLUSIONS
  These results suggest that corneal differentiation following air exposure may regulate HSP72 and HSC70 expression. In addition, HSP72 and HSP90 may protect LSC and corneal cells against oxidative stress.
authors.affiliation: Department of Regenerative Medicine, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran. mebrahimi@royaninstitute.org
authors.forename: Marzeih
authors.initials: M
authors.lastname: Ebrahimi
authors.forename: Parvaneh
authors.initials: P
authors.lastname: Mohammadi
authors.forename: Arezoo
authors.initials: A
authors.lastname: Daryadel
authors.forename: Hossein
authors.initials: H
authors.lastname: Baharvand
mesh_terms: D000328:Adult; D000388:Air; D000650:Amnion / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D048430:Cell Shape; D002478:Cells, Cultured; D018031:Connexin 43 / Q000378:metabolism; D005786:Gene Expression Regulation; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D053558:Keratin-3 / Q000378:metabolism; D017770:Lifting; D008027:Light; D016850:Limbus Corneae / Q000166:cytology*; D012542:Scattering, Radiation; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D018031:Connexin 43; D006360:Heat-Shock Proteins; D053558:Keratin-3
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