Hou Chun-Han, Lin Jinn, Huang Shier-Chieg, Hou Sheng-Mou, Tang Chih-Hsin
Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.
J Cell Physiol. 2009 Jul;220(1):196-203. doi: 10.1002/jcp.21751.
It has been shown that ultrasound (US) stimulation accelerates fracture healing in the animal models and non-operatively clinical uses. Nitric oxide (NO) is a crucial early mediator in mechanically induced bone formation. Here we found that US-mediated inducible nitric oxide synthase (iNOS) expression was attenuated by Ras inhibitor (manumycin A), Raf-1 inhibitor (GW5074), MEK inhibitor (PD98059), NF-kappaB inhibitor (PDTC), and IkappaB protease inhibitor (TPCK). US-induced Ras activation was inhibited by manumycin A. Raf-1 phosphorylation at Ser(338) by US was inhibited by manumycin A and GW5074. US-induced MEK and ERK activation was inhibited by manumycin A, GW5074, and PD98059. Stimulation of preosteoblasts with US activated IkappaB kinase alpha/beta (IKK alpha/beta), IkappaBalpha phosphorylation, p65 phosphorylation at Ser(276), p65, and p50 translocation from the cytosol to the nucleus, and kappaB-luciferase activity. US-mediated an increase of IKK alpha/beta, IkappaBalpha, and p65 phosphorylation, kappaB-luciferase activity and p65 and p50 binding to the NF-kappaB element was inhibited by manumycin A, GW5074, and PD98059. Our results suggest that US increased iNOS expression in preosteoblasts via the Ras/Raf-1/MEK/ERK/IKKalphabeta and NF-kappaB signaling pathways.
研究表明，在动物模型和非手术临床应用中，超声（US）刺激可加速骨折愈合。一氧化氮（NO）是机械诱导骨形成过程中的关键早期介质。在此，我们发现US介导的诱导型一氧化氮合酶（iNOS）表达受到Ras抑制剂（马尼霉素A）、Raf-1抑制剂（GW5074）、MEK抑制剂（PD98059）、NF-κB抑制剂（PDTC）和IκB蛋白酶抑制剂（TPCK）的抑制。马尼霉素A抑制了US诱导的Ras激活。马尼霉素A和GW5074抑制了US诱导的Raf-1在Ser(338)位点的磷酸化。马尼霉素A、GW5074和PD98059抑制了US诱导的MEK和ERK激活。用US刺激前成骨细胞可激活IκB激酶α/β（IKKα/β）、IκBα磷酸化、p65在Ser(276)位点的磷酸化、p65以及p50从细胞质向细胞核的转位，以及κB-荧光素酶活性。马尼霉素A、GW5074和PD98059抑制了US介导的IKKα/β、IκBα和p65磷酸化、κB-荧光素酶活性以及p65和p50与NF-κB元件的结合增加。我们的结果表明，US通过Ras/Raf-1/MEK/ERK/IKKαβ和NF-κB信号通路增加前成骨细胞中iNOS的表达。
