Fig. 2

FGF19 promotes the elongation of mitochondrial morphology by up-regulating the expression of mitochondrial fusion proteins. a RNA sequencing showing the change of mitochondrial metabolism-related genes in chondrocytes induced by FGF19 at 200 ng/ml in the presence of KLB (200 ng/ml). Three pairs of samples were obtained from three independent cell isolates (n = 3), namely, samples 1, 1′, 1′′and 1′′′, samples 2, 2′, 2′′and 2′′′, and samples 3, 3′, 3′′and 3′′′. The data were present as log2(FPKM + 1). FPKM, Fragments per kilobase of exon model per million mapped fragments. b Representative western blotting showing the expression changes of Opa1, Mfn1 and Mfn2 in chondrocytes induced by FGF19 at 200 ng/ml in the presence of KLB (200 ng/ml). The images were chosen based on three independent experiments (n = 3). c Quantification of Opa1, Mfn1 and Mfn2 by western blotting in b was performed to confirm these protein changes (n = 3). d Representative TEM images showing the changes of mitochondrial network’s morphology in chondrocytes induced by FGF19 at 200 ng/ml in the presence of KLB (200 ng/ml). The images were chosen based on three independent experiments (n = 3). Cyan arrows indicated the elongation of mitochondrial morphology. Schematic diagram illustrated that elongation was correlated with mitochondrial fusion. e Measurements of mitochondrial network’s morphology in d by Image J. Quantitative analyses of mitochondrial network’s morphology were based on three independent experiments (n = 3). The data in e were shown as box (from 25, 50 to 75%) and whisker (minimum to maximum values) plots. The significant difference analysis in c and e was based on Student T-test