Fig. 4. Decreased neo-cartilage deposition in C518F FN1 mutant chondrogenic pellets.

(A) Representative images of wild-type and FN1 mutant hiCPC-derived chondrogenic pellets categorized in groups 2 to 4 analyzed by hematoxylin and eosin (H&E), Alcian blue, fibronectin (FN1), collagen type I (COL I), and collagen type II (COL II). Scale bar, 200 μm. (B) Representative images of wild-type and FN1 mutant hiCPC-derived chondrogenic pellets categorized in group 1 analyzed by Alcian blue, fibronectin (FN1), and collagen type II (COL II). Scale bar, 200 μm. (C) Quantification of Alcian blue (AB) staining of Alcian blue–positive areas in wild-type and FN1 mutant hiCPC-derived chondrogenic pellets. (N = 3). (D) Dose-response reduction (Beta = −1.44, P = 2.8 × 10⁻²) of sGAG normalized to DNA in wild-type, FN1 heterozygous (Hetero), and homozygous (Homo) chondrogenic pellets analyzed by dimethylmethylene blue (N = 8). (E) Fibronectin concentration in conditioned medium from FN1 mutant pellets is decreased compared with wild-type, as determined by enzyme-linked immunosorbent assay (N = 3) . Data are means ± SD. P values were determined by generalized estimation equations, with experimental readout (relative Alcian blue intensity, sGAG/DNA, and fibronectin concentration) as dependent variable and genotype as covariate (sGAG/DNA) or factor (relative Alcian blue intensity and fibronectin concentration). *P < 0.05 and ***P < 0.005.