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Stem Cells International
Volume 2016, Article ID 1947157, 13 pages
Research Article

Investigation of the Cell Surface Proteome of Human Periodontal Ligament Stem Cells

1Colgate Australian Clinical Dental Research Centre, School of Dentistry, University of Adelaide, Adelaide, SA 50052, Australia
2Laboratory of Tissue Regeneration and Immunology and Department of Periodontics, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, School of Stomatology, Capital Medical University, Beijing 1000443, China
3School of Medicine, Faculty of Health Sciences, University of Adelaide, Adelaide, SA 50054, Australia
4Oral Microbiology, School of Dentistry, University of Adelaide, Adelaide, SA 50055, Australia
5Mesenchymal Stem Cell Laboratory, School of Medicine, Faculty of Health Sciences, University of Adelaide, Adelaide, SA 50056, Australia
6South Australian Health and Medical Research Institute, Adelaide, SA 5000, Australia

Received 27 May 2016; Accepted 3 July 2016

Academic Editor: Athina Bakopoulou

Copyright © 2016 Jimin Xiong et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The present study examined the cell surface proteome of human periodontal ligament stem cells (PDLSC) compared to human fibroblasts. Cell surface proteins were prelabelled with CyDye before processing to extract the membrane lysates, which were separated using 2D electrophoresis. Selected differentially expressed protein “spots” were identified using Mass spectrometry. Four proteins were selected for validation: CD73, CD90, Annexin A2, and sphingosine kinase 1 previously associated with mesenchymal stem cells. Flow cytometric analysis found that CD73 and CD90 were highly expressed by human PDLSC and gingival fibroblasts but not by keratinocytes, indicating that these antigens could be used as potential markers for distinguishing between mesenchymal cells and epithelial cell populations. Annexin A2 was also found to be expressed at low copy number on the cell surface of human PDLSC and gingival fibroblasts, while human keratinocytes lacked any cell surface expression of Annexin A2. In contrast, sphingosine kinase 1 expression was detected in all the cell types examined using immunocytochemical analysis. These proteomic studies form the foundation to further define the cell surface protein expression profile of PDLSC in order to better characterise this cell population and help develop novel strategies for the purification of this stem cell population.