title: Requirement of leukemia inhibitory factor for establishing and maintaining embryonic stem cells in mice.
abstract: OBJECTIVE
  To evaluate the necessity of leukemia inhibitory factor (LIF) in establishing and self-renewing embryonic stem cells (ESCs).
  
  
  METHODS
  Prospective animal model study.
  
  
  METHODS
  Gamete and Stem Cell Biotechnology Laboratory, Seoul National University, Korea.
  
  
  METHODS
  F1 hybrid B6D2F1 mice.
  
  
  METHODS
  Inner cell mass (ICM) cells of blastocysts were cultured or commercially available ESCs were maintained in LIF-free or LIF-containing medium on mouse embryonic fibroblast (MEF) feeder.
  
  
  METHODS
  Cell morphology, LIF concentration, and mRNA expression.
  
  
  RESULTS
  The MEFs themselves secreted 146.5-175.3 pg/mL LIF in LIF-free medium. The ICM cells formed ESC-like colonies on MEF feeder, and E14 and R1 ESCs were successfully maintained in LIF-free medium. Expression of the genes either mediating LIF function or regulating stemness was not altered significantly, and change in the growth of ESCs was not prominent in LIF-free medium. Neither mRNA expression of differentiation-related genes nor differentiation into embryoid body was changed in the ESCs.
  
  
  CONCLUSIONS
  Addition of LIF to culture medium is not necessary for establishing ICM-derived ESC-like colonies in the presence of fibroblast monolayer, and established ESCs can be maintained in an LIF-free medium.
authors.affiliation: Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea.
authors.forename: Jae Hee
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Clinical Research Institute, Seoul National University, Seoul, Korea.
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Lee
authors.affiliation: Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea.
authors.forename: Chae Hyun
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea.
authors.forename: Jun Hong
authors.initials: JH
authors.lastname: Park
authors.affiliation: Research Institute for Agriculture and Life Science, Seoul National University, Seoul, Korea.
authors.forename: Jae Yong
authors.initials: JY
authors.lastname: Han
authors.affiliation: Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea; Research Institute for Agriculture and Life Science, Seoul National University, Seoul, Korea. Electronic address: limjm@snu.ac.kr.
authors.forename: Jeong Mook
authors.initials: JM
authors.lastname: Lim
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian / Q000166:cytology; D053595:Embryonic Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D053605:Leukemia Inhibitory Factor / Q000378:metabolism / Q000494:pharmacology*; D051379:Mice; D008813:Mice, Inbred ICR; D023421:Models, Animal; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D053605:Leukemia Inhibitory Factor; D012333:RNA, Messenger