Reactive oxygen species derived from Nox4 mediate BMP2 gene transcription and osteoblast differentiation.
Reactive oxygen species derived from Nox4 mediate BMP2 gene transcription and osteoblast differentiation.
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DOI：
10.1042/bj20100357
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发表时间：
2011-01-15
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影响因子：
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通讯作者：
Ghosh-Choudhury N
中科院分区：
文献类型：
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作者：
Mandal CC;Ganapathy S;Gorin Y;Mahadev K;Block K;Abboud HE;Harris SE;Ghosh-Choudhury G;Ghosh-Choudhury N
BMP-2（骨形态发生蛋白-2）促进成骨细胞前体细胞分化为形成健康骨的成熟成骨细胞。在本研究中，我们证明了BMP-2诱导成骨细胞分化的新机制。抗氧化剂NAC（N-乙酰-L-半胱氨酸）和黄素蛋白酶NAD（P）H氧化酶抑制剂DPI（diphenyleneiodonium）阻止BMP-2刺激的小鼠2 T3前成骨细胞碱性磷酸酶表达和矿化骨结节形成。BMP-2引起ROS（活性氧）的快速产生，伴随着NAD（P）H氧化酶的活化增加。NAC和DPI分别抑制BMP-2诱导的ROS产生和NAD（P）H氧化酶活性。NAD（P）H氧化酶显示结构相似的催化亚基（Nox 1 -5），在各种细胞中具有差异表达。我们证明，2 T3前成骨细胞主要表达NAD（P）H氧化酶的Nox 4同种型。为了扩展这一发现，我们测试了Nox 4的功能效应。腺病毒介导的显性负性Nox 4表达抑制BMP-2诱导的碱性磷酸酶表达。BMP-2促进BMP-2的表达以维持成骨细胞表型。NAC和DPI可显著抑制BMP-2刺激的BMP-2 mRNA和蛋白表达，这是由于降低了BMP-2基因的转录。显性负性Nox 4也模仿NAC和DPI的这种作用。我们的研究结果提供了一个新的信号通路连接BMP-2刺激的Nox 4衍生的生理活性氧BMP-2的表达和成骨细胞分化的第一个证据。
BMP-2 (bone morphogenetic protein-2) promotes differentiation of osteoblast precursor cells to mature osteoblasts that form healthy bone. In the present study, we demonstrate a novel mechanism of BMP-2-induced osteoblast differentiation. The antioxidant NAC (N-acetyl-L-cysteine) and the flavoprotein enzyme NAD(P)H oxidase inhibitor DPI (diphenyleneiodonium) preventedBMP-2-stimulated alkaline phosphatase expression and mineralized bone nodule formation inmouse 2T3 pre-osteoblasts. BMP-2 elicited a rapid generation of ROS (reactive oxygen species) concomitant with increased activation of NAD(P)H oxidase. NAC and DPI inhibited BMP-2-induced ROS production and NAD(P)H oxidase activity respectively. NAD(P)H oxidases display structurally similar catalytic subunits (Nox1–5) with differential expression in various cells. We demonstrate that 2T3 pre-osteoblasts predominantly express the Nox4 isotype of NAD(P)H oxidase. To extend this finding, we tested the functional effects of Nox4. Adenovirus-mediated expression of dominant-negative Nox4 inhibited BMP-2-induced alkaline phosphatase expression. BMP-2 promotes expression of BMP-2 for maintenance of the osteoblast phenotype. NAC and DPI significantly blocked BMP-2-stimulated expression of BMP2 mRNA and protein due to a decrease in BMP2 gene transcription. Dominant-negative Nox4 also mimicked this effect of NAC and DPI. Our results provide the first evidence for a new signalling pathway linking BMP-2-stimulated Nox4-derived physiological ROS to BMP-2 expression and osteoblast differentiation.