Activin A maintains pluripotency of human embryonic stem cells in the absence of feeder layers

Stem Cells. 2005 Apr;23(4):489-95. doi: 10.1634/stemcells.2004-0279.


To date, all human embryonic stem cells (hESCs) available for research require unidentified soluble factors secreted from feeder layers to maintain the undifferentiated state and pluripotency. Activation of STAT3 by leukemia inhibitory factor is required to maintain "stemness" in mouse embryonic stem cells, but not in hESCs, suggesting the existence of alternate signaling pathways for self-renewal and pluripotency in human cells. Here we show that activin A is secreted by mouse embryonic feeder layers (mEFs) and that culture medium enriched with activin A is capable of maintaining hESCs in the undifferentiated state for >20 passages without the need for feeder layers, conditioned medium from mEFs, or STAT3 activation. hESCs retained both normal karyotype and markers of undifferentiated cells, including Oct-4, nanog, and TRA-1-60 and remained pluripotent, as shown by the in vivo formation of teratomas.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Activins / metabolism*
  • Animals
  • Antigens, Surface
  • Biomarkers / metabolism
  • Cell Culture Techniques
  • Cell Differentiation
  • Cells, Cultured
  • Culture Media
  • DNA-Binding Proteins / metabolism
  • Embryo, Mammalian / cytology*
  • Fibroblast Growth Factor 7 / metabolism
  • Glycoproteins / metabolism
  • Homeodomain Proteins / metabolism
  • Humans
  • Inhibin-beta Subunits / metabolism*
  • Karyotyping
  • Laminin / metabolism
  • Mice
  • Nanog Homeobox Protein
  • Niacinamide / metabolism
  • Octamer Transcription Factor-3 / metabolism
  • Pluripotent Stem Cells / cytology*
  • Pluripotent Stem Cells / metabolism
  • Proteoglycans
  • Teratoma / pathology


  • Antigens, Surface
  • Biomarkers
  • Culture Media
  • DNA-Binding Proteins
  • Glycoproteins
  • Homeodomain Proteins
  • Laminin
  • NANOG protein, human
  • Nanog Homeobox Protein
  • Octamer Transcription Factor-3
  • Proteoglycans
  • TRA-1-60 antigen, human
  • activin A
  • Activins
  • Fibroblast Growth Factor 7
  • Niacinamide
  • Inhibin-beta Subunits