FIGURE 7.

Fgf9 stabilizes Ptgs2 partially through ERK activation and increased CUGbp2 protein. A, graph of the -fold difference for Ptgs2 and CUGbp2 mRNA following a 3-h treatment of cMSCs with an ERK kinase inhibitor, PD98059 (100 or 300 μm), or 0% serum. B, reducing immunoblot of PD98059-treated cMSCs probed for actin (loading control), phosphorylated ERK, and CUGbp2. C, graph of the quantification of B showing the ratio of CUGbp2/actin protein quantity in cMSCs treated by serum starvation or with PD98059. Base line (1.00) was the ratio of cMSCs grown in 10% serum. D, graph of the -fold difference in CUGbp2 mRNA in cMSCs lentivirally transfected with control shRNA or CUGbp2 shRNAs compared with vector control. E, reducing immunoblot of cMSCs transfected with vector control, control shRNA, or CUGbp2 shRNA showing specific knockdown of CUGbp2 protein. F, graph of the -fold difference for Ptgs2 mRNA in cMSCs transfected with control shRNA and CUGbp2 shRNA versus vector control. Shown is a reducing immunoblot of cMSCs treated with 10% serum, 0% serum, or 0% serum plus Fgf9 (250 ng/ml) (G) and quantification of the ratio of CUGbp2/actin in these cells (H). Base line (1.00) was the ratio of cMSCs grown in 10% serum. Immunoblots and quantifications are representative of three independent experiments. A, D, and F, the asterisks show comparison of data with -fold difference in cells grown in 10% serum. Statistical analysis was performed by Student's t test: *, p < 0.05; **, p < 0.01.