Effects of ADMA upon gene expression: an insight into the pathophysiological significance of raised plasma ADMA.
BACKGROUND
Asymmetric dimethylarginine (ADMA) is a naturally occurring inhibitor of nitric oxide synthesis that accumulates in a wide range of diseases associated with endothelial dysfunction and enhanced atherosclerosis. Clinical studies implicate plasma ADMA as a major novel cardiovascular risk factor, but the mechanisms by which low concentrations of ADMA produce adverse effects on the cardiovascular system are unclear.


RESULTS
We treated human coronary artery endothelial cells with pathophysiological concentrations of ADMA and assessed the effects on gene expression using U133A GeneChips (Affymetrix). Changes in several genes, including bone morphogenetic protein 2 inducible kinase (BMP2K), SMA-related protein 5 (Smad5), bone morphogenetic protein receptor 1A, and protein arginine methyltransferase 3 (PRMT3; also known as HRMT1L3), were confirmed by Northern blotting, quantitative PCR, and in some instances Western blotting analysis to detect changes in protein expression. To determine whether these changes also occurred in vivo, tissue from gene deletion mice with raised ADMA levels was examined. More than 50 genes were significantly altered in endothelial cells after treatment with pathophysiological concentrations of ADMA (2 microM). We detected specific patterns of changes that identify pathways involved in processes relevant to cardiovascular risk and pulmonary hypertension. Changes in BMP2K and PRMT3 were confirmed at mRNA and protein levels, in vitro and in vivo.


CONCLUSIONS
Pathophysiological concentrations of ADMA are sufficient to elicit significant changes in coronary artery endothelial cell gene expression. Changes in bone morphogenetic protein signalling, and in enzymes involved in arginine methylation, may be particularly relevant to understanding the pathophysiological significance of raised ADMA levels. This study identifies the mechanisms by which increased ADMA may contribute to common cardiovascular diseases and thereby indicates possible targets for therapies.
Smith
Caroline L
CL
Centre for Clinical Pharmacology and Therapeutics, Division of Medicine, University College London, London, United Kingdom. c.l.smith@ucl.ac.uk
Anthony
Shelagh
S
Hubank
Mike
M
Leiper
James M
JM
Vallance
Patrick
P
D001120:Arginine / Q000031:analogs & derivatives* / Q000502:physiology; D050197:Atherosclerosis / Q000235:genetics / Q000503:physiopathology*; D055396:Bone Morphogenetic Protein 2; D052005:Bone Morphogenetic Protein Receptors, Type I / Q000096:biosynthesis; D019485:Bone Morphogenetic Proteins / Q000096:biosynthesis; D002318:Cardiovascular Diseases / Q000235:genetics / Q000503:physiopathology; D018929:Cell Culture Techniques; D042783:Endothelial Cells; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000235:genetics / Q000503:physiopathology; D020411:Oligonucleotide Array Sequence Analysis; D011484:Protein-Arginine N-Methyltransferases / Q000096:biosynthesis; D051902:Smad5 Protein / Q000096:biosynthesis; D016212:Transforming Growth Factor beta / Q000096:biosynthesis
C525718:BMP2 protein, human; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; C497797:SMAD5 protein, human; D051902:Smad5 Protein; D016212:Transforming Growth Factor beta; C018524:N,N-dimethylarginine; D001120:Arginine; C413164:PRMT3 protein, human; D011484:Protein-Arginine N-Methyltransferases; C498211:BMPR1A protein, human; D052005:Bone Morphogenetic Protein Receptors, Type I