Role of reactive oxygen species in the signalling cascade of cyclosporine A‐mediated up‐regulation of eNOS in vascular endothelial cells

Abstract

1. Cyclosporine A (CsA) increases eNOS mRNA expression in bovine cultured aortic endothelial cells (BAEC). As some effects of CsA may be mediated by reactive oxygen species (ROS), present experiments were devoted to test the hypothesis that the CsA-induced eNOS up-regulation could be dependent on an increased synthesis of ROS. 2. CsA induced a dose-dependent increase of ROS synthesis, with the two fluorescent probes used, DHR123 (CsA 1 microM: 305+/-7% over control) and H2DCFDA (CsA 1 microM: 178+/-6% over control). 3. Two ROS generating systems, xanthine plus xanthine oxidase (XXO) and glucose oxidase (GO), increased the expression of eNOS mRNA in BAEC, an effect which was maximal after 8 h of incubation (XXO: 168+/-21% of control values. GO: 208+/-18% of control values). The ROS-dependent increased eNOS mRNA expression was followed by an increase in eNOS activity. 4. The effect of CsA on eNOS mRNA expression was abrogated by catalase, and superoxide dismutase (SOD). In contrast, the antioxidant PDTC augmented eNOS mRNA expression, both in basal conditions and in the presence of CsA. 5. The potential participation of the transcription factor AP-1 was explored. Electrophoretic mobility shift assays were consistent with an increase in AP-1 DNA-binding activity in BAEC treated with CsA or glucose oxidase. 6. The present results support a role for ROS, particularly superoxide anion and hydrogen peroxide, as mediators of the CsA-induced eNOS mRNA up-regulation. Furthermore, they situate ROS as potential regulators of gene expression in endothelial cells, both in physiological and pathophysiological situations.

Hydrogen Peroxide Activates Endothelial Nitric-oxide Synthase through Coordinated Phosphorylation and Dephosphorylation via a Phosphoinositide 3-Kinase-dependent Signaling Pathway

“…Drummond et al (35) recently reported that treatment of aortic endothelial cells with H 2 O 2 resulted in increased expression of eNOS protein at the transcriptional level after 18 -24 h, and this increased protein expression resulted in enhanced NO bioactivity. Reactive oxygen species have also been reported to account for the ability of long term cyclosporin A treatment to stimulate eNOS mRNA and protein expression in aortic endothelial cells (36). In the current study, we examined the short term implications of H 2 O 2 on eNOS activity in PAECs.…”

Intracellular redox equilibrium is essential for the constitutive expression of AP-1 dependent genes in resting cells: Studies on TGF-β1 regulation

“…Unlike inducible genes, that are transcribed only when they are needed as a consequence of specific stimuli, constitutive genes are expressed continuously in cells, and it seems that they play significant roles in the maintenance of basic cell processes. Although the transcription level of constitutive genes seems to be rather constant, it has been reported that they can be also regulated by different stimuli, such as reactive oxygen species (ROS) (7,12,18,27,43). …”

Acetylation‐dependent regulation of mitochondrial ALDH2 activation by SIRT3 mediates acute ethanol‐induced eNOS activation

“…In addition, ethanol, as a small exogenous liposoluble molecule, can be metabolized by mitochondrial enzyme systems, accompanied by reactive oxygen species (ROS) generation. ROS have detrimental or beneficial effects on eNOS activation depending on its concentrations [5,6]. During ethanol exposure, ROS level is dependent on the capability of antioxidant systems to antagonize ROS generation.…”