Requirement of leukemia inhibitory factor for establishing and maintaining embryonic stem cells in mice.

OBJECTIVE

To evaluate the necessity of leukemia inhibitory factor (LIF) in establishing and self-renewing embryonic stem cells (ESCs).

DESIGN

Prospective animal model study.

SETTING

Gamete and Stem Cell Biotechnology Laboratory, Seoul National University, Korea.

ANIMAL(S): F1 hybrid B6D2F1 mice.

INTERVENTION(S): 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.

MAIN OUTCOME MEASURE(S): Cell morphology, LIF concentration, and mRNA expression.

RESULT(S): 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.

CONCLUSION(S): 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.