Fluid flow shear stress stimulates human osteoblast proliferation and differentiation through multiple interacting and competing signal transduction pathways
Fluid flow shear stress stimulates human osteoblast proliferation and differentiation through multiple interacting and competing signal transduction pathways
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DOI：
10.1016/s8756-3282(02)00979-1
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发表时间：
2003-03-01
期刊：
影响因子：
4.1
通讯作者：
Lau, KHW
中科院分区：
文献类型：
--
作者：
Kapur, S;Baylink, DJ;Lau, KHW
本研究旨在评估几种信号通路在流体流动剪切应力诱导的正常人成骨细胞增殖和分化中的作用。我们评估了细胞外信号调节激酶（ERK）通路（PD98059和U0126）、一氧化氮合酶通路（N - ω - 硝基 - L - 精氨酸甲酯）、环氧化酶通路（吲哚美辛）或Gi/o通路（百日咳毒素[PTX]）的有效剂量选择性抑制剂对流动介导效应的影响。在20达因/平方厘米的条件下，30分钟的稳定流动剪切应力显著增加了[³H]胸苷掺入量（增殖的一个指标）、碱性磷酸酶活性（成骨细胞分化的一个指标）、ERK的磷酸化以及整合素β1的表达。PD98059、U0126和N - ω - 硝基 - L - 精氨酸甲酯完全阻断了剪切应力诱导的ERK磷酸化、[³H]胸苷掺入量和碱性磷酸酶的增加，但对整合素β1的表达没有影响，这表明ERK和一氧化氮合酶通路对于剪切应力诱导的正常人成骨细胞增殖和分化至关重要，并且每条通路都涉及ERK激活，但不涉及整合素β1的上调。吲哚美辛阻断了剪切应力诱导的成骨细胞增殖和分化以及整合素β1的上调，但不阻断ERK激活，这表明环氧化酶通路（即前列环素和/或前列腺素E₂）以不依赖ERK的方式介导剪切应力诱导的成骨细胞增殖。相比之下，PTX完全阻断了流动诱导的整合素β1表达增加，但对ERK磷酸化或[³H]胸苷掺入量的增加没有影响。PTX不仅没有抑制，反而显著增强了剪切应力对碱性磷酸酶活性的刺激作用，这表明一种对PTX敏感的信号通路可能在成骨细胞分化中起抑制作用。总之，本研究首次表明，成骨细胞中剪切应力的信号转导机制是复杂的，涉及多种依赖ERK和不依赖ERK的通路，并提供了间接证据表明可能存在一种对PTX敏感的通路，它与一种未知通路对正常人成骨细胞的分化具有协同作用。（C）2003年爱思唯尔科学（美国）。保留所有权利。
This study sought to assess the role of several signaling pathways in the fluid flow shear stress-induced proliferation and differentiation of normal human osteoblasts. We evaluated the effects of an effective dose of selective inhibitors of the extracellular signal-regulated kinases (ERK) pathway (PD98059 and U0126), the nitric oxide synthase pathway (N-omega-nitro-L-arginine methyl ester), the cyclo-oxygenase pathway (indomethacin), or the Gi/o pathway (pertussis toxin [PTX]) on the flow-mediated effects. A 30-min steady flow shear stress at 20 dynes/cm(2) increased significantly [H-3]thymidine incorporation (an indicator of proliferation), alkaline phosphatase activity (an index of osteoblast differentiation), phosphorylation of ERK, and expression of integrin beta1. PD98059, U0126, and N-omega-nitro-L-arginine methyl ester completely blocked the shear stress-induced increases in ERK phosphorylation, [H-3]thymidine incorporation, and alkaline phosphatase, but without an effect on integrin beta1 expression, indicating that the ERK and nitric oxide synthase pathways are essential for the shear stress-induced proliferation and differentiation of normal human osteoblasts and that each involves ERK activation but not integrin beta1 upregulation. Indomethacin blocked the shear stress-induced osteoblast proliferation and differentiation and integrin beta1 upregulation but not ERK activation, suggesting that the cyclo-oxygenase pathway (i.e., prostacyclin and/or prostaglandin E-2) mediates the shear stress-induced osteoblast proliferation in an ERK-independent manner. In contrast, PTX completely blocked the flow-induced increase in integrin beta1 expression but had no effect on the increase in the ERK phosphorylation or [H-3]thymidine incorporation. PTX not only did not inhibit but also significantly enhanced the stimulatory effect of shear stress on alkaline phosphatase activity, suggesting that a PTX-sensitive signaling pathway may have an inhibitory role in osteoblast differentiation. In summary, this study shows, for the first time, that the signal transduction mechanism of shear stress in osteoblasts is complex and involves multiple ERK-dependent and independent pathways, and provides circumstantial evidence that there may be a PTX-sensitive pathway that has completing effects with an unknown pathway on the differentiation of normal human osteoblasts. (C) 2003 Elsevier Science (USA). All rights reserved.