Nitric Oxide is Involved in the Down-regulation of SOST Expression Induced by Mechanical Loading
Nitric Oxide is Involved in the Down-regulation of SOST Expression Induced by Mechanical Loading
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DOI：
10.1007/s00223-013-9821-8
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发表时间：
2014-04-01
影响因子：
4.2
通讯作者：
Klein-Nulend, Jenneke
中科院分区：
文献类型：
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作者：
Delgado-Calle, Jesus;Riancho, Jose A.;Klein-Nulend, Jenneke
机械刺激降低啮齿动物中sclerostin的表达。然而，很少有数据是关于人体系统中的物理刺激的影响。最近，我们观察到去甲基化剂AzadC诱导骨细胞中SOST表达。这使得我们在本研究中通过使AzadC处理的人骨细胞经受脉动流体流（PFF）来探索机械负荷对SOST表达的影响。PFF显著降低AzadC诱导的SOST表达。这种作用持续至少24小时，事实上，PFF处理后24小时的SOST表达低于PFF处理后1小时的SOST表达（PFF/静态比分别为0.47 +/- A 0.04对0.63 +/- A 0.03，p = 0.03）。PFF诱导的SOST表达减少不是由于SOST启动子甲基化谱的改变。然而，PFF刺激一氧化氮（NO）的合成，这似乎是必不可少的PFF对SOST表达的影响。事实上，NO合酶抑制剂1400 W阻止了PFF对SOST表达的影响。此外，NO供体SNAP降低SOST mRNA在骨器官培养。经历PFF的细胞的条件培养基（CM）在静态培养物中诱导SOST表达降低38 +/-Δ 4%（p = 0.03），并降低具有克隆的SOST启动子的报告载体的转录活性（静态-CM：1.47 +/-Δ 0.10对比PFF-CM：0.78 +/-Δ 0.09，p = 0.02）。这与PFF诱导的调节SOST的因子分泌一致。我们的研究结果表明，NO和其他可溶性因子参与PFF抑制SOST表达。
Mechanical stimulation reduces sclerostin expression in rodents. However, few data are available about the effect of physical stimuli in human systems. Recently we observed that the demethylating agent AzadC induces SOST expression in bone cells. This allowed us in this study to explore the effect of mechanical loading on SOST expression by subjecting AzadC-treated human bone cells to pulsating fluid flow (PFF). PFF significantly decreased the AzadC-induced expression of SOST. This effect persisted for at least 24 h, and in fact SOST expression was lower at 24 h after PFF treatment than at 1 h after PFF treatment (PFF/static ratio 0.47 +/- A 0.04 vs. 0.63 +/- A 0.03 respectively, p = 0.03). The PFF-induced decrease in SOST expression was not due to a change in the methylation profile of the SOST promoter. However, PFF stimulated nitric oxide (NO) synthesis, which appeared essential for the PFF effect on SOST expression. In fact, the NO synthase inhibitor 1400 W prevented the effect of PFF on SOST expression. Moreover, the NO-donor SNAP decreased SOST mRNA in bone organ cultures. The conditioned medium (CM) of cells subjected to PFF induced a 38 +/- A 4 % decrease in SOST expression (p = 0.03) in static cultures and diminished the transcriptional activity of reporter vectors with the cloned SOST promoter (Static-CM: 1.47 +/- A 0.10 vs. PFF-CM: 0.78 +/- A 0.09, p = 0.02). This is consistent with a PFF-induced secretion of factors that modulate SOST. Our results suggest that NO and other soluble factors are involved in the inhibition of SOST expression by PFF.