Transcription Factor TCF4 Maintains the Properties of Human Corneal Epithelial Stem Cells§

Authors

  • Rong Lu,

    1. Zhongshan Ophthalmic Center, State Key Laboratory of Ophthalmology, Sun Yat-Sen University, Guangzhou, People's Republic of China
    2. Ocular Surface Center, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA
    Search for more papers by this author
  • Yangluowa Qu,

    1. Ocular Surface Center, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA
    2. The Eye Institute, Xiamen University, Xiamen, People's Republic of China
    Search for more papers by this author
  • Jian Ge,

    Corresponding author
    1. Zhongshan Ophthalmic Center, State Key Laboratory of Ophthalmology, Sun Yat-Sen University, Guangzhou, People's Republic of China
    • Zhongshan Ophthalmic Center, State Key Laboratory of Ophthalmology, Sun Yat-Sen University, Guangzhou, People's Republic of China
    Search for more papers by this author
    • Telephone: +86 20 87333209; Fax: +86 20 87333271

  • Lili Zhang,

    1. Ocular Surface Center, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA
    2. Department of Ophthalmology, the Affiliated Hospital of Qingdao University Medical College, Qingdao, People's Republic of China
    Search for more papers by this author
  • Zhitao Su,

    1. Ocular Surface Center, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA
    Search for more papers by this author
  • Stephen C. Pflugfelder,

    1. Ocular Surface Center, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA
    Search for more papers by this author
  • De-Quan Li

    Corresponding author
    1. Ocular Surface Center, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA
    • Ocular Surface Center, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, 6565 Fannin Street, NC-205, Houston, Texas 77030, USA
    Search for more papers by this author
    • Telephone: 713-798-1123; Fax: 713-798-1457


  • Author contributions: R.L.: conception and design, provision of study material, collection and/or assembly of data, data analysis and interpretation, and manuscript writing; Y.Q.: provision of study material, collection and/or assembly of data, data analysis and interpretation, and manuscript writing; J.G.: conception and design, financial support, manuscript writing, and final approval of manuscript; L.Z. and Z.S.: provision of study material or patients and collection and/or assembly of data; S.C.P.: conception and design, financial support, and manuscript writing; and D.-Q.L.: conception and design, financial support, collection and/or assembly of data, data analysis and interpretation, manuscript writing, and final approval of manuscript.

  • Disclosure of potential conflicts of interest is found at the end of this article.

  • §

    First published online in STEM CELLSEXPRESS January 9, 2012.

Abstract

TCF4, a key transcription factor of Wnt signaling system, has been recently found to be essential for maintaining stem cells. However, its signaling pathway is not well elucidated. This study was to explore the functional roles and signaling pathway of TCF4 in maintaining adult stem cell properties using human corneal epithelial stem cells as a model. With immunofluorescent staining and real-time polymerase chain reaction, we observed that TCF4 was exclusively expressed in the basal layer of human limbal epithelium where corneal epithelial stem cells reside. TCF4 was found to be well colocalized with ABCG2 and p63, two recognized epithelial stem/progenitor cell markers. Using in vitro culture models of primary human corneal epithelial cells, we revealed that TCF4 mRNA and protein were upregulated by cells in exponential growth stage, and RNA interference by small interfering RNA-TCF4 (10-50 nM) transfection blocked TCF4 signaling and suppressed cell proliferation as measured by WST-1 assay. TCF4 silence was found to be accompanied by downregulated proliferation-associated factors p63 and survivin, as well as upregulated cyclin-dependent kinase inhibitor 1C (p57). By creating a wound healing model in vitro, we identified upregulation and activation of β-catenin/TCF4 with their protein translocation from cytoplasm to nuclei, as evaluated by reverse transcription-quantitative real-time polymerase chain reaction, immunostaining, and Western blotting. Upregulated p63/survivin and downregulated p57 were further identified to be TCF4 downstream molecules that promote cell migration and proliferation in wound healing process. These findings demonstrate that transcription factor TCF4 plays an important role in determining or maintaining the phenotype and functional properties of human corneal epithelial stem cells. STEM CELLS2012; 30:753–761

Ancillary