ES micro-environment enhances stemness and inhibits apoptosis in human limbal stem cells via the maintenance of telomerase activity

PLoS One. 2013;8(1):e53576. doi: 10.1371/journal.pone.0053576. Epub 2013 Jan 11.

Abstract

Our previous work had found that telomerase rejuvenated in the cytoplasm of corneal epithelial cells cultured in embryonic stem cell-conditioned medium, the functional properties of stem-like corneal epithelial cells can be enhanced by co-culturing with embryonic stem cells (ESCs) via activation of the integrinβ1-FAK-PI3K/Akt signaling pathway. The goal of this study was to explore the potential molecular mechanisms of the ES micro-environment that enhance the stem cell-like phenotype and inhibit apoptosis in human limbal stem cells (LSC). The LSC were cultured in different media, either CnT-20 medium or CnT-20 +20% ES culture supernatant (ESC-CM). We observed that LSC cultured in ESC-CM had an increased proliferative capacity, greater serial passage capacity, higher colony-forming efficiency (CFE) and higher levels of stem cell-associated marker than those cultured in CnT-20. Compared with CnT-20, ESC-CM enhanced the undifferentiated status and inhibited apoptosis in the LSC by promoting the maintenance of telomerase activity, which could reduce the generation of reactive oxygen species (ROS), maintain the membrane potential (Δψm) at higher levels and reduce the expression of the p21 protein. Our findings indicated that ESC-CM system induced LSC to maintain a stem cell phenotype and inhibit the process of apoptosis. These effects might partially be achieved via the telomerase-p21-mitochondrial axis and the activation of the FAK/Wnt signaling pathways. This study may have high impact and clinic implication on the expansion of LSC in regenerative medicine, especially for ocular surface reconstruction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis* / drug effects
  • Cell Differentiation / drug effects
  • Cell Proliferation / drug effects
  • Cells, Cultured
  • Cellular Microenvironment* / drug effects
  • Colony-Forming Units Assay
  • Culture Media, Conditioned / pharmacology
  • Embryonic Stem Cells / cytology*
  • Embryonic Stem Cells / enzymology*
  • Focal Adhesion Protein-Tyrosine Kinases / metabolism
  • Humans
  • Limbus Corneae / cytology*
  • Mice
  • Models, Biological
  • RNA Interference / drug effects
  • Telomerase / metabolism*
  • Wnt Signaling Pathway / drug effects

Substances

  • Culture Media, Conditioned
  • Focal Adhesion Protein-Tyrosine Kinases
  • Telomerase

Grants and funding

This study was supported by Grant No. 2012AA020507 from the National High Technology Research and Development Program (863 program) of China, Grant No. 2011B090400353 from Guangdong Province e Ministry of Education Industry-University-Research Institute Collaboration Project of China, Grant No. 90035-3283310 from Sun Yat-Sen University 985 Project of China and the Fundamental Research Funds of State Key Laboratory of Ophthalmology of China. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.