title: Gingival fibroblasts as a promising source of induced pluripotent stem cells.
abstract: BACKGROUND
  Induced pluripotent stem (iPS) cells efficiently generated from accessible tissues have the potential for clinical applications. Oral gingiva, which is often resected during general dental treatments and treated as biomedical waste, is an easily obtainable tissue, and cells can be isolated from patients with minimal discomfort.
  
  
  RESULTS
  We herein demonstrate iPS cell generation from adult wild-type mouse gingival fibroblasts (GFs) via introduction of four factors (Oct3/4, Sox2, Klf4 and c-Myc; GF-iPS-4F cells) or three factors (the same as GF-iPS-4F cells, but without the c-Myc oncogene; GF-iPS-3F cells) without drug selection. iPS cells were also generated from primary human gingival fibroblasts via four-factor transduction. These cells exhibited the morphology and growth properties of embryonic stem (ES) cells and expressed ES cell marker genes, with a decreased CpG methylation ratio in promoter regions of Nanog and Oct3/4. Additionally, teratoma formation assays showed ES cell-like derivation of cells and tissues representative of all three germ layers. In comparison to mouse GF-iPS-4F cells, GF-iPS-3F cells showed consistently more ES cell-like characteristics in terms of DNA methylation status and gene expression, although the reprogramming process was substantially delayed and the overall efficiency was also reduced. When transplanted into blastocysts, GF-iPS-3F cells gave rise to chimeras and contributed to the development of the germline. Notably, the four-factor reprogramming efficiency of mouse GFs was more than 7-fold higher than that of fibroblasts from tail-tips, possibly because of their high proliferative capacity.
  
  
  CONCLUSIONS
  These results suggest that GFs from the easily obtainable gingival tissues can be readily reprogrammed into iPS cells, thus making them a promising cell source for investigating the basis of cellular reprogramming and pluripotency for future clinical applications. In addition, high-quality iPS cells were generated from mouse GFs without Myc transduction or a specific system for reprogrammed cell selection.
authors.affiliation: Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan. egu@dent.osaka-u.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Egusa
authors.forename: Keisuke
authors.initials: K
authors.lastname: Okita
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kayashima
authors.forename: Guannan
authors.initials: G
authors.lastname: Yu
authors.forename: Sho
authors.initials: S
authors.lastname: Fukuyasu
authors.forename: Makio
authors.initials: M
authors.lastname: Saeki
authors.forename: Takuya
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Shinya
authors.initials: S
authors.lastname: Yamanaka
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Yatani
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D046508:Culture Techniques; D005347:Fibroblasts / Q000166:cytology* / Q000378:metabolism; D015870:Gene Expression; D005881:Gingiva / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology* / Q000378:metabolism; D000090062:Kruppel-Like Factor 4; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D014157:Transcription Factors