BACKGROUND AND OBJECTIVE

Human induced pluripotent stem (iPS) cells, which have similar properties to human embryonic stem (hES) cells, have been generated from neonatal and adult human dermal fibroblasts by reprogramming. iPS cells have high pluripotency and differentiation potential, and may be a potential autologous stem cell source for future regenerative therapy.

MATERIAL AND METHODS

iPS cell lines from human gingival fibroblasts and, for the first time, from periodontal ligament fibroblasts, were generated by reprogramming using a retroviral transduction cocktail of OCT3/4, SOX2, KLF4 and c-MYC. iPS induction was investigated through expression of the embryonic stem cell markers SSEA4, OCT4, NANOG, GCTM-2, TG30 and TRA-1-60. Following in vitro differentiation, the expression of genes for differentiation markers for ectoderm (SOX1, PAX6), mesoderm [RUNX1, T(Brachyury)] and endoderm (GATA4, AFP) was assessed by real-time RT-PCR. The ability to form teratomas following implantation into mouse testes was assessed by histology.

RESULTS

Human gingival fibroblast- and periodontal ligament fibroblast-derived iPS cells showed similar characteristics to hES cells. Both sets of iPS cells displayed colony morphology comparable to that of hES cells and expressed the hES cell-associated cell-surface antigens, SSEA3, SSEA4, GCTM-2, TG30 (CD9) and Tra-1-60, and the hES cell marker genes, OCT4, NANOG and GDF3. These iPS cells showed differentiation potential to form embryoid bodies in vitro and expressed genes for endoderm, ectoderm and mesoderm. Teratoma formation following implantation into mouse testes was observed.

CONCLUSION

These results demonstrate that iPS cells can be successfully generated from adult human gingival and periodontal ligament fibroblasts.