Comparison of Different Systems for Chondrogenic Differentiation of Human Embryonic Stem Cells: The Effect of TGF-beta1

Abstract

In this study, we demonstrated the potential of hESCs to undergo chondrogenic differentiation under different culture environment and examined the effect of transforming growth factor beta1 (TGFbeta1). When undifferentiated hESCs were seeded directly as micromass without embryoid body (EB) formation (referred to as ESC-direct), the serum-free basic chondrogenic media alone (referred as control) was sufficient to induce chondrogenesis, indicated by increased expression of chondrogenic markers. With treatment of TGFbeta1, down-regulation of chondrogenic markers was observed. Further investigation demonstrated that TGFbeta1 prolonged the pluripotency markers Oct4 and Nanog during differentiation. In comparison, chondrogenesis in EB-derived micromass was not drastically affected by TGFbeta1. Furthermore, the study also showed that chondrogenesis in EB-derived micromass was exquisitely sensitive to cell seeding density. Extend of chondrogenesis was diminished with increased seeding density. Unlike mesenchymal stem cells, hESCs cultured as pellets did not undergo chondrogenesis with no detection of aggrecan or collagen II.