Human feeder cells support establishment and definitive endoderm differentiation of human embryonic stem cells.

Mouse embryonic fibroblasts (MEFs) have been extensively used as feeder cells to support the in vitro propagation of human embryonic stem cells (hESCs). However, owing to the risk of cross-contamination with animal or other unknown pathogens, the use of MEFs does not meet requirements for the clinical application of hESCs. Moreover, the actual role played by the feeders in the differentiation of hESCs is still unclear. In this study, human embryonic fibroblasts (HEFs) were used as feeder cells to support the establishment and undifferentiated growth of hESCs, and the capability of HEFs to induce the differentiation of definitive endoderm (DE) was evaluated. Three new hES cell lines were derived. These cell lines exhibited and maintained the common features of traditional hESCs after prolonged culture in vitro. Furthermore, DE differentiation of the newly established hES cell lines was performed using 100 ng/ml activin A, and the effects were compared among HEFs, MEFs, and feeder-free systems. On day 5 of induction, DE (SOX17(+)) cells appeared with comparable efficiency in both human and mouse feeder systems (85.0 +/- 8.9% and 78.7 +/- 3.4%, respectively). These levels were considerably superior to that obtained in the feeder-free system (22.7 +/- 5.6%). The SOX17(+) cells tended to differentiate into an endodermal lineage in vivo and could be further induced into glucagon and C-peptide double positive islet-like clusters in vitro. Our studies suggest that, in terms of therapeutic application, HEFs can be an effective substitute for MEFs for sustaining the derivation and DE differentiation of hESCs.