Journal: JBMR Plus
Article Title: Sphingosine‐1‐Phosphate Modulates the Effect of Estrogen in Human Osteoblasts
doi: 10.1002/jbm4.10037
Figure Lengend Snippet: Short‐term effect of S1P or E2 on osteoblast estrogen receptors, SPHK activity, and MAPK pathways. ( A ) Effect of 24‐hour treatment with 1 μM S1P or 10 nM E2 on ER, S1PR, and SPHK1 mRNA expression. Note the concentration‐dependent increase in ERβ (ii), S1PR1 (iii), and SPHK1 (iv) mRNA expression. Expression of ERα mRNA (i) was unaffected. Effect of estradiol, 10 nM, on mRNAs for SPHK1 at 24 hours (iv). Real‐time PCR normalized to GAPDH, mean ± range, n = 2 (independent experiments with 2 to 4 replicates). * p < 0.05, ** p < 0.01 versus control. ( B ) Effect of (i) 200 nM or 1000 nM S1P or (ii) 10 nM estradiol on sphingosine kinase activity. S1P stimulated the production of fluorescently labeled S1P, reflecting sphingosine kinase activity in osteoblast lysates, after treatment for 15 minutes with unlabeled S1P, pmoles/min/mg protein. Effects of estradiol were similar; separate experiments with separate controls. Mean ± SEM, n = 3 ** p < 0.01 versus control. ( C ) On Western blot, SPHK1 protein production was increased at 24 hours by 10 nM estradiol, or the durable S1P receptor 1 agonist SEW2871, 1 μM. ( D ) Effect of S1P (100 nM) on AKT and ERK phosphorylation in h‐MSC in 5 and 15 minutes. S1P increased phospho‐AKT and phospho‐ERK at 15 minutes relative to AKT and ERK or to β‐actin. ( E ) S1P effect on AKT and ERK phosphorylation in hOB. S1P increased phospho‐AKT at 200 nM and 1000 nM S1P and slightly increase phospho‐ERK at 1000 nM. ( C – E ) Quantification of two ECL blot images normalized to equal total protein to eliminate artifacts of different loading or detection efficiency. * p < 0.05; ** p < 0.01, ns (not significant).
Article Snippet: The S1P receptor‐1 (S1PR1) agonist SEW2871 was from Tocris (Bristol, UK).
Techniques: Activity Assay, Expressing, Concentration Assay, Real-time Polymerase Chain Reaction, Control, Labeling, Western Blot, Phospho-proteomics