Hilenski Lula L, Clempus Roza E, Quinn Mark T, Lambeth J David, Griendling Kathy K
Division of Cardiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
Arterioscler Thromb Vasc Biol. 2004 Apr;24(4):677-83. doi: 10.1161/01.ATV.0000112024.13727.2c. Epub 2003 Dec 11.
Reactive oxygen species (ROS) that act as signaling molecules in vascular smooth muscle cells (VSMC) and contribute to growth, hypertrophy, and migration in atherogenesis are produced by multi-subunit NAD(P)H oxidases. Nox1 and Nox4, two homologues to the phagocytic NAD(P)H subunit gp91phox, both generate ROS in VSMC but differ in their response to growth factors. We hypothesize that the opposing functions of Nox1 and Nox4 are reflected in their differential subcellular locations.
We used immunofluorescence to visualize the NAD(P)H subunits Nox1, Nox4, and p22phox in cultured rat and human VSMC. Optical sectioning using confocal microscopy showed that Nox1 is co-localized with caveolin in punctate patches on the surface and along the cellular margins, whereas Nox4 is co-localized with vinculin in focal adhesions. These immunocytochemical distributions are supported by membrane fractionation experiments. Interestingly, p22phox, a membrane subunit that interacts with the Nox proteins, is found in surface labeling and in focal adhesions in patterns similar to Nox1 and Nox4, respectively.
The differential roles of Nox1 and Nox4 in VSMC may be correlated with their differential compartmentalization in specific signaling domains in the membrane and focal adhesions.
多亚基烟酰胺腺嘌呤二核苷酸磷酸（NAD(P)H）氧化酶可产生作为血管平滑肌细胞（VSMC）信号分子并参与动脉粥样硬化发生过程中生长、肥大和迁移的活性氧（ROS）。Nox1和Nox4是吞噬细胞NAD(P)H亚基gp91phox的两个同源物，二者均可在VSMC中产生活性氧，但对生长因子的反应不同。我们推测Nox1和Nox4相反的功能反映在它们不同的亚细胞定位上。
我们使用免疫荧光技术观察培养的大鼠和人类VSMC中NAD(P)H亚基Nox1、Nox4和p22phox。利用共聚焦显微镜进行光学切片显示，Nox1与小窝蛋白共定位于细胞表面和细胞边缘的点状斑块中，而Nox4与纽蛋白共定位于黏着斑中。这些免疫细胞化学分布得到了膜分离实验的支持。有趣的是，与Nox蛋白相互作用的膜亚基p22phox分别以与Nox1和Nox4相似的模式出现在表面标记物和黏着斑中。
Nox1和Nox4在VSMC中的不同作用可能与其在膜和黏着斑中特定信号域的不同区室化有关。
