title: Neural stem cells achieve and maintain pluripotency without feeder cells.
abstract: BACKGROUND
  Differentiated cells can be reprogrammed into pluripotency by transduction of four defined transcription factors. Induced pluripotent stem cells (iPS cells) are expected to be useful for regenerative medicine as well as basic research. Recently, the report showed that mouse embryonic fibroblasts (MEF) cells are not essential for reprogramming. However, in using fibroblasts as donor cells for reprogramming, individual fibroblasts that had failed to reprogram could function as feeder cells.
  
  
  RESULTS
  Here, we show that adult mouse neural stem cells (NSCs), which are not functional feeder cells, can be reprogrammed into iPS cells using defined four factors (Oct4, Sox2, Klf4, and c-Myc) under feeder-free conditions. The iPS cells, generated from NSCs expressing the Oct4-GFP reporter gene, could proliferate for more than two months (passage 20). Generated and maintained without feeder cells, these iPS cells expressed pluripotency markers (Oct4 and Nanog), the promoter regions of Oct4 and Nanog were hypomethylated, could differentiated into to all three germ layers in vitro, and formed a germline chimera. These data indicate that NSCs can achieve and maintain pluripotency under feeder-free conditions.
  
  
  CONCLUSIONS
  This study suggested that factors secreted by feeder cells are not essential in the initial/early stages of reprogramming and for pluripotency maintenance. This technology might be useful for a human system, as a feeder-free reprogramming system may help generate iPS cells of a clinical grade for tissue or organ regeneration.
authors: Department of Biomedical Science, Stem Cell and Developmental Biology, CHA University, Seoul, Republic of Korea.
authors: Hyun Woo
authors: HW
authors: Choi
authors: Jong Soo
authors: JS
authors: Kim
authors: Sol
authors: S
authors: Choi
authors: Hyo Jin
authors: HJ
authors: Jang
authors: Min Jung
authors: MJ
authors: Kim
authors: Youngsok
authors: Y
authors: Choi
authors: Hans R
authors: HR
authors: Schöler
authors: Hyung Min
authors: HM
authors: Chung
authors: Jeong Tae
authors: JT
authors: Do
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods*; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D065150:Cellular Reprogramming / Q000235:genetics / Q000502:physiology; D061252:Feeder Cells / Q000166:cytology / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D057026:Induced Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism; D000090062:Kruppel-Like Factor 4; D051379:Mice; D058953:Neural Stem Cells / Q000166:cytology* / Q000378:metabolism; D050814:Octamer Transcription Factor-3 / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D050814:Octamer Transcription Factor-3