Fig. 1

FSCN1 expression is upregulated along with chondrocyte dedifferentiation and OA pathogenesis. a, b SOFG staining and IHC of FSCN1, Osteoarthritis Research Society International (OARSI) grades and quantification of FSCN1-positive cells (a), IF staining of FSCN1 (green) and Collagen type III (red) (b) in cartilage from intact (control) and damaged articular cartilage sections collected from OA patients (n = 8). c, d Safranin O/Fast Green (SOFG) staining, immunofluorescence (IF) staining of FSCN1, OARSI grades (c), western blot analysis of FSCN1, Collagen type II, MMP13, Collagen type I and III protein levels (d) in articular cartilage from mice with baseline or DMM-induced OA at 6- or 10-weeks post-surgery. The inset in each image is shown as a magnified image in the bottom row (n = 5). e IF staining and quantification of FSCN1 (green) and Collagen type III (red) in articular cartilage from mice with sham or DMM-induced OA at 6 weeks post-surgery (n = 5). SOFG staining and OARSI grades (f), IF staining of FSCN1 (green) and Collagen type III (red) (g) in cartilage from young (2-month-old) and aged (12-month-old) mice (n = 5). h-i. Optical microscopy, IF staining of FSCN1 (red) and phalloidin staining of F-actin structures (green) (h), western blot analysis of the protein level of FSCN1, Collagen type II, Sox9, Collagen type I and III protein levels (i) in mouse primary chondrocytes at passage 0 (P0) and passage 4 (P4) (n = 3). Scale bars, 50 μm. All data are presented as means ± SEM