title: Direct reprogramming of rat neural precursor cells and fibroblasts into pluripotent stem cells.
abstract: BACKGROUND
  Given the usefulness of rats as an experimental system, an efficient method for generating rat induced pluripotent stem (iPS) cells would provide researchers with a powerful tool for studying human physiology and disease. Here, we report direct reprogramming of rat neural precursor (NP) cells and rat embryonic fibroblasts (REF) into iPS cells by retroviral transduction using either three (Oct3/4, Sox2, and Klf4), four (Oct3/4, Sox2, Klf4, and c-Myc), or five (Oct3/4, Sox2, Klf4, c-Myc, and Nanog) genes.
  
  
  RESULTS
  iPS cells were generated from both NP and REF using only three (Oct3/4, Sox2, and Klf4) genes without c-Myc. Two factors were found to be critical for efficient derivation and maintenance of rat iPS cells: the use of rat instead of mouse feeders, and the use of small molecules specifically inhibiting mitogen-activated protein kinase and glycogen synthase kinase 3 pathways. In contrast, introduction of embryonic stem cell (ESC) extracts induced partial reprogramming, but failed to generate iPS cells. However, when combined with retroviral transduction, this method generated iPS cells with significantly higher efficiency. Morphology, gene expression, and epigenetic status confirmed that these rat iPS cells exhibited ESC-like properties, including the ability to differentiate into all three germ layers both in vitro and in teratomas. In particular, we found that these rat iPS cells could differentiate to midbrain-like dopamine neurons with a high efficiency.
  
  
  CONCLUSIONS
  Given the usefulness of rats as an experimental system, our optimized method would be useful for generating rat iPS cells from diverse tissues and provide researchers with a powerful tool for studying human physiology and disease.
authors.affiliation: Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, United States of America.
authors.forename: Mi-Yoon
authors.initials: MY
authors.lastname: Chang
authors.forename: Dohoon
authors.initials: D
authors.lastname: Kim
authors.forename: Chun-Hyung
authors.initials: CH
authors.lastname: Kim
authors.forename: Hoon-Chul
authors.initials: HC
authors.lastname: Kang
authors.forename: Eungi
authors.initials: E
authors.lastname: Yang
authors.forename: Jung-Il
authors.initials: JI
authors.lastname: Moon
authors.forename: Sanghyeok
authors.initials: S
authors.lastname: Ko
authors.forename: Junpil
authors.initials: J
authors.lastname: Park
authors.forename: Kyung-Soon
authors.initials: KS
authors.lastname: Park
authors.forename: Kyung-Ah
authors.initials: KA
authors.lastname: Lee
authors.forename: Dong-Youn
authors.initials: DY
authors.lastname: Hwang
authors.forename: Young
authors.initials: Y
authors.lastname: Chung
authors.forename: Robert
authors.initials: R
authors.lastname: Lanza
authors.forename: Kwang-Soo
authors.initials: KS
authors.lastname: Kim
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D053595:Embryonic Stem Cells / Q000166:cytology*; D044127:Epigenesis, Genetic; D005347:Fibroblasts / Q000166:cytology*; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology*; D000090062:Kruppel-Like Factor 4; D051379:Mice; D009474:Neurons / Q000166:cytology*; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012190:Retroviridae / Q000235:genetics; D013301:Streptolysins / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse; C000715469:Klf4 protein, rat; D000090062:Kruppel-Like Factor 4; D016271:Proto-Oncogene Proteins c-myc; D013301:Streptolysins; C025964:streptolysin O