Figure 7

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 (Nox1) was involved in native low-density lipoprotein (nLDL)-induced superoxide generation and proliferation. (a) Human aortic smooth muscle cells (hAoSMCs) were trypsinized after the incubation of 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS; 100 μM) (as a Cl⁻ channel inhibitor) for 30 min, and lucigenin-dependent chemiluminescence was measured with or without nLDL stimulation. nLDL-induced superoxide generation was significantly blocked with DIDS incubation (* vs untreated, P<0.01; # vs nLDL, P<0.01). (b) Small interfering RNAs (siRNAs) against Nox1 and Nox2 were transfected into hAoSMCs (upper), respectively, and superoxide generation (middle) and cell proliferation (lower) were measured. Decreased Nox1 protein (by siRNA transfection) was associated with the prevention of nLDL-induced superoxide generation and cell proliferation; however, Nox2 was not involved in superoxide generation in nLDL-stimulated hAoSMCs. (c) Transfection of siRNA against NoxO1 prevented reactive oxygen species (ROS) generation in nLDL-stimulated vascular smooth muscle cells (VSMCs; * vs untreated, P<0.01; # vs nLDL, P<0.05).