Author + information
- Received August 10, 1999
- Revision received June 16, 2000
- Accepted August 16, 2000
- Published online December 1, 2000.
- Rainer H Böger, MDa,
- Stefanie M Bode-Böger, MDa,
- Philip S Tsao, PhDa,
- Patrick S Lin, BSa,
- Jason R Chan, BSa and
- John P Cooke, MD, PhDa,* ()
- ↵*Reprint requests and correspondence to: Dr. John P. Cooke, Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305-5406
We sought to determine whether asymmetric dimethylarginine (ADMA) inhibits nitric oxide (NO) elaboration in cultured human endothelial cells and whether this is associated with the activation of oxidant-sensitive signaling mediating endothelial adhesiveness for monocytes.
Endothelial NO elaboration is impaired in hypercholesterolemia and atherosclerosis, which may be due to elevated concentrations of ADMA, an endogenous inhibitor of NO synthase.
Human umbilical vein endothelial cells (ECV 304) and human monocytoid cells (THP-1) were studied in a functional binding assay. Nitric oxide and superoxide anion (O2−) were measured by chemiluminescence; ADMA by high pressure liquid chromatography; monocyte chemotactic protein-1 (MCP-1) by ELISA and NF-κB by electromobility gel shift assay.
Incubation of endothelial cells with ADMA (0.1 μM to 100 μM) inhibited NO formation, which was reversed by coincubation with L-arginine (1 mM). The biologically inactive stereoisomer symmetric dimethylarginine did not inhibit NO release. Asymmetric dimethylarginine (10 μM) or native low-density lipoprotein cholesterol (100 mg/dL) increased endothelial O2− to the same degree. Asymmetric dimethylarginine also stimulated MCP-1 formation by endothelial cells. This effect was paralleled by activation of the redox-sensitive transcription factor NF-κB. Preincubation of endothelial cells with ADMA increased the adhesiveness of endothelial cells for THP-1 cells in a concentration-dependent manner. Asymmetric dimethylarginine-induced monocyte binding was diminished by L-arginine or by a neutralizing anti-MCP-1 antibody.
We concluded that the endogenous NO synthase inhibitor ADMA is synthesized in human endothelial cells. Asymmetric dimethylarginine increases endothelial oxidative stress and potentiates monocyte binding. Asymmetric dimethylarginine may be an endogenous proatherogenic molecule.
☆ Supported, in part, by a grant from the National Heart, Lung and Blood Institute (1R01-HL-58638) and the Tobacco-Related Disease Research Program. Dr. Böger is the recipient of a postdoctoral grant from the Boehringer Ingelheim foundation. Dr. Bode-Böger received a postdoctoral grant from the Deutsche Forschungsgemeinschaft. Dr. Tsao is the recipient of a National Service Research Award (1F32-HL-08779).
- Received August 10, 1999.
- Revision received June 16, 2000.
- Accepted August 16, 2000.
- American College of Cardiology