Fig. 1.

Chondrogenic Differentiation of human pluripotent stem cells. Human pluripotent stem cells were chondrogenically differentiated in a two-step process (A). Following mesoderm induction, a decrease in pluripotency markers Nanog, Oct3/4 and Sox2 was detected, while the primitive streak markers Brachyury, MIXL1 and KDR transiently upregulated after 36 h of differentiation. Upon chondrogenic differentiation, an increase in Col2A1 and ACAN was detected. Although Sox9 was upregulated during mesoderm induction, its expression remained steady during differentiation (B). Glycosaminoglycan-rich nodules were detected on day 14 (C). These nodules progressively matured into Safranin-O (D) and collagen type II (E)-positive aggregates. Data represent observations collected from experiments using the CY2 cell line; similar observations were made when using NCRM1, 604B1 and H9 cells. Statistical significance is represented as follows: *p < 0.05; **p < 0.01; ***p < 0.001; and ****p < 0.0001