Fig. 5: FGF19 mediates cell cycle arrest at G2 phase by activating FGFR4-p38/MAPK axis.

A Representative western blots showed that FGF19 (200 ng/ml) combined with KLB stimulation of chondrocytes causes changes in the expression of p-p38 for 6 h in the presence or absence of BLU9931 (5 μM). B Quantification analysis to confirm the protein changes in (A). C Representative IF images presenting chondrocytes pretreated with 5 μM BLU9931 for 2 h and stimulated with 200 ng/ml FGF19 and KLB for 6 h showed less nuclear translocation of p-p38 in comparison to the group treated solely with FGF19 and KLB. (Cytoskeleton, green; p-p38, red; Nucleus, blue). D Representative western blots showed that FGF19 (200 ng/ml) combined with KLB stimulation of chondrocytes causes changes in the expression of cdk1, cylinb1, chk1 and gadd45a in the presence or absence of SB203580 (10 μM). E Representative IF pictures presenting chondrocytes with higher cdk1 expression pretreated with 10 μM SB203580 for 2 h in the presence of 200 ng/ml FGF19 and KLB. Cytoskeleton, green; Cdk1, red; Nucleus, blue. F Quantification of the linear fluorescent intensity of cdk1 in chondrocytes shown in (E). G Representative IF pictures presenting chondrocytes with higher cylinb1 expression after pretreatment with 10 μM SB203580 for 2 h in the presence of 200 ng/ml FGF19 and KLB. Cytoskeleton, green; Cylinb1, red; Nucleus, blue. H Quantification of the linear fluorescent intensity of cylinb1 in chondrocytes shown in (G). The data in B, F and H are presented as the means ± SD, and the significant data presented in B were based on two-tailed Student’s t-tests. Experiments presented in A, C–E and G were based on at least three independent repeats (n ≥ 3).