title: Generation of functional cardiomyocytes from mouse induced pluripotent stem cells.
abstract: BACKGROUND
  Induced pluripotent stem (iPS) cells allow derivation of autologous differentiated cells for cell therapy. The purpose of this study was to compare the cardiac differentiation potential of mouse iPS cells with embryonic stem (ES) cells and demonstrate that they could produce functional cardiomyocytes.
  
  
  METHODS
  iPS cells were prepared from mouse embryonic fibroblasts by lentiviral mediated expression of four transcription factors (Oct4/Sox2/Klf4/C-myc). To induce cardiac cell differentiation, iPS-S-6 or D3-ES cells were induced to form embryoid bodies (EBs) using a two-medium culture protocol, then plated onto gelatin-coated plates and maintained in DMEM.
  
  
  RESULTS
  Following classification of the generation periods of contracting EBs into early (d8-d11), middle (d12-d15) and late (d16-20), iPS cells in the early period exhibited characteristics similar to ES cells. In iPS cells from the middle period group, the ratio of contracting EBs was significantly increased compared to ES cells, and the difference persisted in cells from the late period group (p<0.05). The percentage of contracting EBs formed from iPS and ES cells were 44.8% and 33.3%, respectively. In addition, iPS cell-derived cardiomyocytes exhibited mRNA expression of cardiac mesoderm markers such as GATA4 and NKX2.5, and cardiomyocyte markers such as α1s, α1c, α-MHC, β-MHC, Cx40, TnI, TnT, ANF and Hey2. Single cardiomyocytes exhibited typical cross-striated myofibrillar organization, and electrophysiological studies revealed functional cardiac-specific voltage-gated Na(+), Ca(2+) and K(+) channels.
  
  
  CONCLUSIONS
  These results demonstrate that functional cardiomyocytes can be generated from iPS cells, and suggest that these cells may be useful for the treatment of cardiovascular disease.
authors.affiliation: Mirae Biotech, Seoul 143-854, Republic of Korea.
authors.forename: Kyoung Ha
authors.initials: KH
authors.lastname: So
authors.forename: Young Joon
authors.initials: YJ
authors.lastname: Han
authors.forename: Hyo Young
authors.initials: HY
authors.lastname: Park
authors.forename: Jae Gon
authors.initials: JG
authors.lastname: Kim
authors.forename: Dong Jun
authors.initials: DJ
authors.lastname: Sung
authors.forename: Young Min
authors.initials: YM
authors.lastname: Bae
authors.forename: Byoung Chul
authors.initials: BC
authors.lastname: Yang
authors.forename: Soo Bong
authors.initials: SB
authors.lastname: Park
authors.forename: Sang Keun
authors.initials: SK
authors.lastname: Chang
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Kim
authors.forename: Se Pill
authors.initials: SP
authors.lastname: Park
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D002478:Cells, Cultured; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000502:physiology*; D000090062:Kruppel-Like Factor 4; D008564:Membrane Potentials / Q000502:physiology; D051379:Mice; D032383:Myocytes, Cardiac / Q000502:physiology*