McAllister Heart Institute, Department of Medicine, University of North Carolina, Chapel Hill, NC 27599-7005, USA.
Circulation. 2010 Feb 2;121(4):549-59. doi: 10.1161/CIRCULATIONAHA.109.908319. Epub 2010 Jan 18.
Despite a concerted effort by many laboratories, the critical subunits that participate in vascular smooth muscle cell (VSMC) NADPH oxidase function have yet to be elucidated. Given the potential therapeutic importance of cell-specific inhibition of NADPH oxidase, we investigated the role of Nox activator 1 (NoxA1), a homolog of p67phox, in VSMC NADPH oxidase function and atherosclerosis.
The presence of NoxA1 in mouse aortic VSMCs was confirmed by reverse-transcription polymerase chain reaction and sequencing. NoxA1/p47phox interaction after thrombin treatment was observed by immunoprecipitation/Western analysis of lysates from p47phox(-/-) VSMCs transfected with adenoviral HA-NoxA1 and Myc-p47phox. Infection with adenoviral NoxA1 significantly enhanced thrombin-induced reactive oxygen species generation in wild-type but not in p47phox(-/-) and Nox1(-/-) VSMCs. Thrombin-induced reactive oxygen species production and VSMC proliferation were significantly reduced after downregulation of NoxA1 with shRNA. Infection with NoxA1 shRNA but not scrambled shRNA significantly decreased thrombin-induced activation of the redox-sensitive protein kinases (Janus kinase 2, Akt, and p38 mitogen-activated protein kinase) in VSMCs. Adenovirus-mediated overexpression of NoxA1 in guidewire-injured mouse carotid arteries significantly increased superoxide production in medial VSMCs and enhanced neointimal hyperplasia. NoxA1 expression was significantly increased in aortas and atherosclerotic lesions of ApoE(-/-) mice compared with age-matched wild-type mice. Furthermore, in contrast to p67phox, immunoreactive NoxA1 is present in intimal and medial SMCs of human early carotid atherosclerotic lesions.
NoxA1 is the functional homolog of p67phox in VSMCs that regulates redox signaling and VSMC phenotype. These findings support the potential for modulation of NoxA1 expression as a viable approach for the treatment of vascular diseases.
尽管许多实验室都进行了协同努力，但参与血管平滑肌细胞 (VSMC) NADPH 氧化酶功能的关键亚基尚未阐明。鉴于细胞特异性抑制 NADPH 氧化酶的潜在治疗重要性，我们研究了 Nox 激活物 1 (NoxA1) 在 VSMC NADPH 氧化酶功能和动脉粥样硬化中的作用。
通过逆转录聚合酶链反应和测序证实了 NoxA1 在小鼠主动脉 VSMC 中的存在。通过免疫沉淀/Western 分析转染了腺病毒 HA-NoxA1 和 Myc-p47phox 的 p47phox(-/-) VSMC 裂解物，观察到血栓素处理后 NoxA1/p47phox 相互作用。感染腺病毒 NoxA1 可显著增强野生型 VSMC 中血栓素诱导的活性氧生成，但在 p47phox(-/-)和 Nox1(-/-) VSMC 中则不然。用 shRNA 下调 NoxA1 可显著降低血栓素诱导的 VSMC 增殖。感染 NoxA1 shRNA 而非乱序 shRNA 可显著降低 VSMC 中氧化还原敏感蛋白激酶（Janus 激酶 2、Akt 和 p38 丝裂原活化蛋白激酶）的血栓素诱导激活。在导丝损伤的小鼠颈总动脉中，腺病毒介导的 NoxA1 过表达可显著增加中膜 VSMC 中的超氧化物产生并增强新生内膜增生。与年龄匹配的野生型小鼠相比，ApoE(-/-) 小鼠的主动脉和动脉粥样硬化病变中 NoxA1 的表达明显增加。此外，与 p67phox 不同，免疫反应性 NoxA1 存在于人类早期颈动脉粥样硬化病变的内膜和中膜 SMC 中。
NoxA1 是 VSMC 中 p67phox 的功能同源物，可调节氧化还原信号和 VSMC 表型。这些发现支持调节 NoxA1 表达作为治疗血管疾病的可行方法。
