Journal: The Journal of Biological Chemistry
Article Title: Involvement of mitogen- and stress-activated protein kinase 1 in BMP-6–induced chondrocyte differentiation
doi: 10.1016/j.jbc.2024.107806
Figure Lengend Snippet: Phosphorylation of MSK1 via the p38 kinase pathway upon BMP-6 stimulation in ATDC5 cells. A , phosphorylation of MSK1 (Ser376) and MSK1 (Ser360) by BMP-6. ATDC5 cells were stimulated with 25 ng/ml BMP-6 for the indicated times. The total cell lysates were then used for Western blot analyses. The total expression levels of phospho-MSK1 (Ser376), phospho-MSK1 (Ser360), MSK1, phospho-ERK1/2 (Thr202/Tyr204), phospho-p38 (Thr180/Tyr182), phospho-JNK (Thr183/Tyr185), phospho-Smad1/5, and β-actin are indicated in the upper, second, third, fourth, fifth, sixth, seventh , and bottom panels , respectively. The intensity of the bands for phospho-MSK1 (Ser376) and phospho-MSK1 (Ser360) was normalized to the intensity of the band corresponding to MSK1. Relative intensity was calculated with respect to the 1-h treatment of cells with BMP-6. B , Inhibition of BMP-6-induced MSK1 phosphorylation by dorsomorphin, a BMP type I receptor kinase inhibitor. ATDC5 cells were pretreated with 10 μM dorsomorphin for 1 h. Thereafter, cells were stimulated with 25 ng/ml BMP-6 for the indicated times. The total cell lysates were used for Western blot analyses. The total expression levels of phospho-MSK1 (Ser376), phospho-MSK1 (Ser360), MSK1, phospho-CREB (Ser133), phospho-Smad1/5, Smad5, and β-actin are indicated in the upper, second, third, fourth, fifth, sixth , and bottom panels , respectively. The intensity of the bands for phospho-MSK1 (Ser376) and phospho-MSK1 (Ser360) was normalized to the intensity of the band corresponding to MSK1. The intensity of the band for phospho-CREB (Ser133) was normalized to the intensity of the band corresponding to β-actin. Relative intensity was calculated with respect to the 1-h treatment of cells with BMP-6 in the absence of dorsomorphin. C , Involvement of the ERK pathway in the phosphorylation of MSK1 by BMP-6. ATDC5 cells were pretreated with 20 μM U0126 1 h before stimulation with 25 ng/ml BMP-6 for the indicated times. The total expression levels of phospho-MSK1 (Ser376), phospho-MSK1 (Ser360), MSK1, phospho-CREB (Ser133), phospho-ERK1/2 (Thr202/Tyr204), ERK1/2, phospho-Smad1/5, Smad5, and β-actin are indicated in the upper, second, third, fourth, fifth, sixth, seventh, eighth , and bottom panels , respectively. The intensity of the bands for phospho-MSK1 (Ser376) and phospho-MSK1 (Ser360) was normalized to the intensity of the band corresponding to MSK1. The intensity of the band for phospho-CREB (Ser133) was normalized to the intensity of the band corresponding to β-actin. Relative intensity was calculated with respect to the 1-h treatment of cells with BMP-6 in the absence of U0126. D , decrease in BMP-6-induced phosphorylation of MSK1 in the presence of the p38 kinase inhibitor. ATDC5 cells pretreated with 10 μM SB203580, a p38 kinase inhibitor, for 1 h were stimulated with 25 ng/ml BMP-6 for the indicated times. The total expression levels of phospho-MSK1 (Ser376), phospho-MSK1 (Ser360), MSK1, phospho-CREB (Ser133), phospho-p38 (Thr180/Tyr182), p38, phospho-Smad1/5, Smad5, and β-actin are indicated in the upper, second, third, fourth, fifth, sixth, seventh, eighth , and bottom panels , respectively. The intensity of the bands for phospho-MSK1 (Ser376) and phospho-MSK1 (Ser360) was normalized to the intensity of the band corresponding to MSK1. The intensity of the band for phospho-CREB (Ser133) was normalized to the intensity of the band corresponding to β-actin. Relative intensity was calculated with respect to the 1-h treatment of cells with BMP-6 in the absence of SB203580. A-D , white and black arrowheads indicate phospho-MSK1 (Ser376)-specific and nonspecific bands, respectively. E , decrease in BMP-6-mediated phospho-CREB (Ser133) expression by the MSK1 kinase inhibitor, SB747651A. ATDC5 cells were cultured with 10 μM SB747651A for 1 h. Prior to preparation of the total lysates, 25 ng/ml BMP-6 was added to the culture media for the indicated times. The total expression levels of phospho-CREB (Ser133), phospho-p38 (Thr180/Tyr182), phospho-Smad1/5, Smad5, and β-actin are indicated in the upper, second, third, fourth , and bottom panels , respectively. The intensity of the band for phospho-CREB (Ser133) was normalized to the intensity of the band corresponding to β-actin. Relative intensity was calculated with respect to the 1-h treatment of cells with BMP-6 in the absence of SB747651A. F , chondrogenic differentiation of ATDC5 cells by BMP-6 in the presence of kinase inhibitors. ATDC5 cells cultured at a high density were stimulated with 25 ng/ml BMP-6 in the presence (+) or absence (−) of kinase inhibitors (20 μM U0126, 10 μM SB203580, 10 μM SB747651A, or 10 μM dorsomorphin). Two weeks later, the cells were stained with Alcian blue. Representative images are shown. The intensity of the area stained with Alcian blue was measured using ImageQuant TL. The relative intensity of the stained area was calculated with respect to the 1-h treatment of cells with BMP-6 alone. G , representative images of ex vivo chondrogenic differentiation of mouse metatarsal bones induced by BMP-6 in the presence of kinase inhibitors. Each mouse metatarsal bone was cultured with or without 25 ng/ml BMP-6 for 7 days, either in the absence or presence of kinase inhibitors (20 μM U0126, 10 μM SB203580, 10 μM SB747651A, or 10 μM dorsomorphin). Then, each bone was stained with Alcian blue and Alizarin Red S. Two representative images are shown in each treatment. a , proliferative chondrocytes; b , clear zone represented as hypertrophic chondrocytes; c , chondrocyte matrix calcified by mature hypertrophic chondrocytes stained with alizarin red S. H , relative area of chondrocyte differentiation in mouse metatarsal bones induced by BMP-6 in the presence of kinase inhibitors. The total areas of chondrocyte differentiation (a + b + c) were measured. The total areas of chondrocyte differentiation (a + b + c) were measured using ImageJ. Asterisks indicate significant differences. BMP, bone morphogenetic protein; CREB, cAMP-response element-binding protein; MSK, mitogen- and stress-activated protein kinase; ND; not determined.
Article Snippet: The intensity of each band was measured using ImageQuant TL analysis software (Cytiva) after each gel image was captured with the ImageQuant LAS 4000 mini (Amersham).
Techniques: Phospho-proteomics, Western Blot, Expressing, Inhibition, Cell Culture, Staining, Ex Vivo, Binding Assay