期刊
JOURNAL OF VASCULAR RESEARCH
卷 50, 期 5, 页码 410-420出版社
KARGER
DOI: 10.1159/000354225
关键词
Endothelial cells; Endothelial nitric oxide synthase; ERK; Hydrogen peroxide; Oxidative stress; Reactive oxygen species; ROCK
资金
- Codan
- Pfizer
- AstraZeneca
- Apotekerfonden
- McKinney Moller og hustrus fond til almene formal
- Astra Florida Bolding
- Bernhard and Marie Klein Foundation
Background: Hydrogen peroxide (H2O2) is produced in vessels during ischemia/reperfusion and during inflammation, both leading to vascular dysfunction. We investigated cellular pathways involved in endothelial nitric oxide synthase (eNOS) phosphorylation at Threonine 495 (Thr(495)) in human umbilical vein endothelial cells (HUVECs) exposed to H2O2. Methods: HUVECs were exposed to 400 mu m H2O2 for 30 min. Phosphorylation at Thr(495) was assessed by Western blotting and reactive oxygen species (ROS) monitored by flow cytometry. Protein kinase C (PKC) pathways were investigated by pretreatment with PKC-beta inhibitor ruboxistaurin or pan-PKC inhibitor GF109203X. In addition, we investigated ROCK and ERK pathways by MEKK1/2 inhibitor U0126 and ROCK inhibitor Y27632. Results: H2O2 increased eNOS phosphorylation at Thr(495) (to 176% vs. control (100%), p < 0.001) along with increased mitochondrial ROS formation (from 19.7 to 45.3%, p < 0.01). This rise in phosphorylation could be prevented by U0126 and Y27632 in a dose-dependent manner, but did not result in lowered mitochondrial ROS formation. Conversely, addition of the antioxidant N-acetyl-L-cysteine only prevented mitochondrial ROS formation but did not prevent phosphorylation of eNOS Thr(495). Conclusion: H2O2-mediated phosphorylation of eNOS Thr(495) is mediated by ROCK and ERK activity, but not by PKC, and is uncoupled from mitochondrial ROS signaling. Furthermore, ERK inhibition increased mitochondrial ROS formation. (C) 2013 S. Karger AG, Basel
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