Hebchen Dana Maureen, Spaeth Manuela, Müller Niklas, Schröder Katrin
Institute for Cardiovascular Physiology, Goethe University Frankfurt, 60298 Frankfurt, Germany.
German Center of Cardiovascular Research (DZHK), Partner Site RheinMain, 60596 Frankfurt, Germany.
Antioxidants (Basel). 2024 Sep 14;13(9):1113. doi: 10.3390/antiox13091113.
The Nox1-centered NADPH oxidase complex facilitates the transfer of electrons from intracellular NADPH across the cell membrane to extracellular molecular oxygen, resulting in the formation of superoxide. The complex is comprised of two membrane-bound subunits, namely Nox1 and p22phox, and the cytosolic subunits, namely NoxA1 and NoxO1. The presence of NoxO1 facilitates the proximity of all components, thereby enabling the complex to exhibit constitutive activity. Despite the theoretical sufficiency of all subunits in a 1:1 ratio, the precise composition of the Nox1-centered NADPH oxidase remains unknown. Analyses of mRNA expression in different cell lines revealed an unequal expression of the components, with an excess of NoxO1. Furthermore, plasmid-based overexpression of individual components of the Nox1-centered NADPH oxidase resulted in an excess of NoxO1 mRNA. The objective of this study was to analyze the ability of NoxO1 to control the level of ROS formation by the Nox1 complex. To this end, we generated Hek293 cells for constitutive expression of Nox1 and NoxA1, which were then transfected with increasing concentrations of NoxO1. The data presented herein suggests that ROS formation by the Nox1-centered NADPH oxidase is dependent on the concentration of NoxO1. A surplus of NoxO1 has been observed to exert control over the activity of the complex in accordance with a dose-dependent mechanism. We thus conclude that the ratio of Nox1, NoxA1, and NoxO1 complexes does not adhere to a 1:1 ratio. Conversely, the availability of NoxO1 serves to regulate the formation of ROS by the Nox1-centered NADPH oxidase.
以Nox1为中心的NADPH氧化酶复合物促进电子从细胞内的NADPH穿过细胞膜转移到细胞外的分子氧，从而形成超氧化物。该复合物由两个膜结合亚基，即Nox1和p22phox，以及胞质亚基，即NoxA1和NoxO1组成。NoxO1的存在促进了所有组分的接近，从而使该复合物表现出组成型活性。尽管所有亚基理论上以1:1的比例就足够了，但以Nox1为中心的NADPH氧化酶的精确组成仍然未知。对不同细胞系中mRNA表达的分析显示各组分表达不均，NoxO1过量。此外，以质粒为基础对以Nox1为中心的NADPH氧化酶的各个组分进行过表达导致NoxO1 mRNA过量。本研究的目的是分析NoxO1控制Nox1复合物形成ROS水平的能力。为此，我们构建了组成型表达Nox1和NoxA1的Hek293细胞，然后用浓度递增的NoxO1进行转染。本文给出的数据表明，以Nox1为中心的NADPH氧化酶形成ROS取决于NoxO1的浓度。已观察到过量的NoxO1根据剂量依赖性机制对复合物活性进行控制。因此我们得出结论，Nox1、NoxA1和NoxO1复合物的比例并不遵循1:1的比例。相反，NoxO1的可用性用于调节以Nox1为中心的NADPH氧化酶形成ROS。
