Fig. 4
Effect of BMP pathway inhibition or PTHrP pulse treatment on endochondral marker expression
MSCs were subjected to chondrogenic induction for 28 days in the presence of CompA, LDN21 or received PTHrP pulse treatment. Expression levels of (A) hypertrophic and osteogenic marker genes, referred to the respective control cultures (dashed lines, n = 6 donors). (B) Western blotting of type II collagen and type X collagen extracted from 1 pellet per group. Representative results from one of four experiments (n = 4 donors) are shown. Please note, that pepsin digestion used for collagen extraction degrades all other proteins, so that typical loading controls cannot be provided. The image was cropped for conciseness as indicated and full-length blots are presented in supplementary Fig. S7. (C) Densitometric quantification of the Western blots in (B) (n = 4). (D) Alkaline phosphatase (ALP) activity was determined in culture supernatants in weekly intervals (n = 6 donors). Data are referred to respective control cultures (dashed lines) and shown as mean and standard deviation. (E) ALP activity on day 28 referred to respective control cultures (dashed lines). Box plots were generated as described in Fig. 3. * p ≤ 0.05 Mann-Whitney U test with Bonferroni correction compared to respective controls and between treatments