Abstract 19048: Tissue-Specific Regulation of Phospholipase C Beta-3 by Asymmetric Dimethylarginine (ADMA)
Elevated concentrations of the endogenous NO synthase inhibitor ADMA correlate with endothelial dysfunction and increased cardiovascular risk. ADMA is degraded by the enzyme DDAH. DDAH1-transgenic (DDAH1) mice show an increased NO production and are protected against inflammatory responses in graft coronary artery disease and ischemia reperfusion injury. The aim of this study was to identify ADMA-regulated genes in aortic tissue. Microarray gene expression analyses were performed in aortic tissue of DDAH1 male mice, wild-type littermates (WT), and C57Bl/6 (C57) mice with or without chronic ADMA infusion (50 mg/kg/body weight) via osmotic minipumps. DDAH1 mice showed lower ADMA plasma concentrations (DDAH1 vs. WT; 0.52±0.04 vs. 0.68±0.05 μmol/l, p<0.05) determined by LC-MS/MS, whereas ADMA-treated animals presented high ADMA levels (C57 vs. C57+ADMA; 0.83±0.03 vs. 3.30±0.21 μmol/l, p<0.001). Chronic ADMA infusion and DDAH1 overexpression resulted in a significant up- and downregulation of genes, particularly involved in metabolism, cellular defense, transcriptional regulation, and signal transduction. We compared the gene array data of both groups with regard to conversely regulated genes, since these genes are most likely ADMA-dependent. 23 genes revealed a converse regulation, with 3 genes upregulated by ADMA and downregulated in DDAH1 mice. In particular, phospholipase C-beta 3 (PLC beta-3) gene expression presented a significant converse regulation in aortic tissue, which was confirmed by RT-PCR experiments (WT/C57 1.01±0.08, DDAH1 0.20±0.12, C57+ADMA 2.24±0.13). Interstingly, PLC beta-3 was regulated in a tissue-specific manner, since gene expression was not significantly altered in heart, liver, and kidney tissues. We identified ADMA-regulated genes in aortic tissue which are mainly involved in transcriptional regulation, metabolism, cellular defense, and signal transduction. Specifically, PLC beta 3, which plays an important role in the interaction of neutrophils and macrophages, demonstrated an ADMA-dependent and tissue-specific regulation. Further investigations are necessary to elucidate the underlying mechanisms of ADMA-dependent PLC beta-3 regulation in the context of cardiovascular disease.
- © 2010 by American Heart Association, Inc.