PPARγ regulates hypoxia-induced Nox4 expression in human pulmonary artery smooth muscle cells through NF-κB
PPARγ regulates hypoxia-induced Nox4 expression in human pulmonary artery smooth muscle cells through NF-κB
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DOI：
10.1152/ajplung.00090.2010
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发表时间：
2010-10-01
影响因子：
4.9
通讯作者：
Hart, C. Michael
中科院分区：
文献类型：
--
作者：
Lu, Xianghuai;Murphy, Tamara C.;Hart, C. Michael
Lu X，Murphy TC，Nanes MS，哈特CM.过氧化物酶体增殖物激活受体γ通过核因子-κ B调节缺氧诱导的人肺动脉平滑肌细胞Nox 4表达美国生理学杂志肺细胞分子生理学299：L559-L566，2010年。首次发表于2010年7月9日; doi：10.1152/ajplung.00090.2010。NADPH氧化酶是血管系统中产生超氧化物的主要来源。组成型活性Nox 4亚基在具有肺动脉高压的人类受试者和实验动物的肺中选择性上调，在血管壁细胞中高度表达。我们证明，罗格列酮，过氧化物酶体增殖物激活受体-γ（过氧化物酶体增殖物激活受体γ）的合成激动剂，减弱缺氧诱导的肺动脉高压，血管重塑，Nox 4诱导，和活性氧在小鼠肺中的产生。本研究探讨了人肺动脉平滑肌细胞（HPASMC）中过氧化物酶体增殖物激活受体γ（PPAR γ）调节的低氧诱导的Nox 4表达的分子机制。暴露于1%的氧72小时增加HPASMC的Nox 4基因表达和H2 O2的生产，这两个减少与罗格列酮治疗在最后24小时的缺氧暴露或治疗与小干扰RNA（siRNA）的Nox 4。缺氧还增加了HPASMC的增殖以及Nox 4启动子荧光素酶报告基因的活性，而罗格列酮可以减弱这些增加。染色质免疫沉淀分析表明，缺氧增加NF-κ B B亚基，p65，Nox 4启动子的结合，并通过罗格列酮治疗减弱。NF-κ B B在Nox 4调控中的作用进一步得到了证实，p65的过表达刺激了Nox 4启动子活性，而针对p50或p65的siRNA减弱了Nox 4启动子活性的缺氧刺激。这些结果为NF-κ B介导的HPASMC中Nox 4表达的刺激提供了新的证据，该刺激可由PPAR γ负调控。这些数据提供了对潜在机制的新见解，通过该机制，PPAR γ激活抑制Nox 4上调和肺血管壁中细胞的增殖，以改善肺动脉高压和响应缺氧的血管重塑。
Lu X, Murphy TC, Nanes MS, Hart CM. PPAR gamma regulates hypoxia-induced Nox4 expression in human pulmonary artery smooth muscle cells through NF-kappa B. Am J Physiol Lung Cell Mol Physiol 299: L559-L566, 2010. First published July 9, 2010; doi:10.1152/ajplung.00090.2010.-NADPH oxidases are a major source of superoxide production in the vasculature. The constitutively active Nox4 subunit, which is selectively upregulated in the lungs of human subjects and experimental animals with pulmonary hypertension, is highly expressed in vascular wall cells. We demonstrated that rosiglitazone, a synthetic agonist of the peroxisome proliferator-activated receptor-gamma (PPAR gamma), attenuated hypoxia-induced pulmonary hypertension, vascular remodeling, Nox4 induction, and reactive oxygen species generation in the mouse lung. The current study examined the molecular mechanisms involved in PPAR gamma-regulated, hypoxia-induced Nox4 expression in human pulmonary artery smooth muscle cells (HPASMC). Exposing HPASMC to 1% oxygen for 72 h increased Nox4 gene expression and H2O2 production, both of which were reduced by treatment with rosiglitazone during the last 24 h of hypoxia exposure or by treatment with small interfering RNA (siRNA) to Nox4. Hypoxia also increased HPASMC proliferation as well as the activity of a Nox4 promoter luciferase reporter, and these increases were attenuated by rosiglitazone. Chromatin immunoprecipitation assays demonstrated that hypoxia increased binding of the NF-kappa B subunit, p65, to the Nox4 promoter and that binding was attenuated by rosiglitazone treatment. The role of NF-kappa B in Nox4 regulation was further supported by demonstrating that overexpression of p65 stimulated Nox4 promoter activity, whereas siRNA to p50 or p65 attenuated hypoxic stimulation of Nox4 promoter activity. These results provide novel evidence for NF-kappa B-mediated stimulation of Nox4 expression in HPASMC that can be negatively regulated by PPAR gamma. These data provide new insights into potential mechanisms by which PPAR gamma activation inhibits Nox4 upregulation and the proliferation of cells in the pulmonary vascular wall to ameliorate pulmonary hypertension and vascular remodeling in response to hypoxia.