Oxidative stress may play an important role in the regulation of MMP activity. Augmented MMP activity may be involved in the development of ventricular remodelling in patients with coronary artery disease.

No abstract

Abstract-We demonstrated recently that plasma concentrations of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthase, are increased by high salt intake concomitantly with a decrease in plasma levels of NO in human hypertension. We investigated the effect of shear stress on ADMA release in 2 types of cells: transformed human umbilical vein endothelial cells (HUVECs; cell line ECV-304) and HUVECs. Exposure of ECV-304 cells and HUVECs to shear stress with the use of a cone-plate viscometer enhanced gene expression of protein arginine methyltransferase (PRMT-1), ADMA synthase. In HUVECs, the ratio of PRMT-1 to glyceraldehyde 3-phosphate dehydrogenase mRNA was increased by 2-fold by a shear stress of Ն15 dyne/cm 2 . A dominant-negative mutant of IB kinase ␣ and troglitazone at 8 mol/L, an activator of peroxisome proliferator-activated receptor ␥, abolished the shear stress-induced increase in PRMT-1 gene expression in parallel with the blockade of nuclear factor (NF)-B translocation into the nucleus. The activity of dimethylarginine dimethylaminohydrolase, the degradation enzyme of ADMA, was unchanged after shear stress Յ15 dyne/cm 2 and was enhanced by 1.48Ϯ0.06-fold (PϽ0.05) by shear stress at 25 dyne/cm 2 . The release of ADMA was increased by 1.64Ϯ0.10-fold (PϽ0.05) by shear stress at 15 dyne/cm 2 but was not affected by shear stress at 25 dyne/cm 2 . These results indicate that shear stress enhances gene expression of PRMT-1 and ADMA release via activation of the NF-B pathway. Shear stress at higher magnitudes facilitates the degradation of ADMA, thus returning ADMA release levels to baseline. Key Words: stress, mechanical Ⅲ endothelium Ⅲ gene expression Ⅲ arginine Ⅲ nitric oxide Ⅲ nitric oxide synthase N itric oxide (NO) contributes to vessel homeostasis by inhibiting vascular smooth muscle tone and growth, platelet aggregation, and leukocyte adhesion to the endothelium. 1 Altered biosynthesis of NO has been implicated in the pathogenesis of atherosclerosis, and it is possible that accumulation of endogenous asymmetric dimethylarginine (ADMA), an endogenous competitive inhibitor of NO synthase (NOS), underlies the reduced NO generation. We demonstrated recently that a high salt intake decreases the plasma concentrations of nitrite and nitrate (NO x ) concomitantly with an increase in plasma concentrations of ADMA in patients with essential hypertension. 2 A high salt intake causes a number of physiologic and pathologic effects, such as hemodynamic modulation, increased activity of the reninangiotensin-aldosterone system, and activation of the sympathetic nerve system. High salt intake-induced hemodynamic modulation includes augmentation of shear stress to the vascular wall, especially to endothelial cells, and we hypothesized that a high salt intake-induced decrease in plasma NO x levels might be caused by a shear stress-induced elevation of circulating ADMA.Vascular endothelial cells are capable of synthesizing ADMA, which is derived from the catabolism of proteins containi...

To clarify the physiological significance of the intranuclear speckled distribution, or foci formation, of liganded steroid receptors, the subnuclear distribution of green (GFP), yellow (YFP), and cyan (CFP) fluorescent protein-tagged receptors and coactivators was investigated. The foci formation of 5 alpha-dihydrotestosterone (DHT)-bound AR-GFP in COS7 cells was abolished by the cotransfection of a CBP Delta (118-2393) fragment eliciting a dominant negative effect on the transactivation capacity of the AR. The N-terminal AR fragment (AR-AF-1-YFP), which has a strong constitutive transactivation function, formed foci without DHT, whereas the C-terminal AR fragment (AR-AF-2-CFP), which has a quite low transactivation function, was distributed homogeneously even in the presence of DHT. The reporter gene assay showed a synergism between the transactivation functions of AR-AF-1 and AR-AF-2. This synergism was not reflected by the above two-dimensional imaging. In contrast, a three-dimensional imaging method clearly showed a difference in the intranuclear spatial distribution. The DHT-bound wild-type AR-GFP alone or AR-AF-1-YFP plus DHT-bound AR-AF-2-CFP was distributed as approximately 300 discrete spots in one nucleus, whereas AR-AF-1-YFP alone was distributed as one volume in a reticular pattern. Furthermore, not only AR but also the glucocorticoid receptor-YFP, ER alpha -GFP, and YFP-tagged SRC-1, TIF2, and CBP were found to be accumulated in identical spots in the presence of ligand. All of the above results indicate that CBP is one of the factors essential for foci formation of the AR, and may propose the hypothesis that transcriptionally activated steroid receptors, regardless of the type of receptor, are transferred to common compartments (foci) and form a complex with coactivators, and this process is essential to full transactivation.

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, is elevated in congestive heart failure (CHF) concomitantly with the higher levels of nitric oxide (NO) and cytokines. We investigated the association among ADMA, NO, and cytokines in human CHF. Blood was collected from 25 patients with acutely exacerbated chronic CHF (acute CHF, mean age 61 +/- 3 years), 23 patients with chronic compensated CHF (chronic CHF, mean age 62 +/- 2 years), and 26 control subjects (mean age 51 +/- 1 years). ADMA was measured by high-performance liquid chromatography. Tumor necrosis factor-alpha (TNF-alpha) was measured by enzyme-linked immunosorbent assay. Nitrate plus nitrite (NOx) was measured by the Griess method. The plasma levels of ADMA and TNF-Alpha were higher in patients with acute CHF than in those with chronic CHF and control subjects (both P < 0.05). The plasma level of NOx was higher in patients with chronic CHF than in those with acute CHF and control subjects (both P < 0.01). The plasma level of TNF-Alpha was positively correlated with that of ADMA in combination with patients with acute and chronic CHF (r = 0.31, P < 0.01). The plasma level of ADMA was, furthermore, negatively correlated with that of NOx (r = -0.29, P < 0.05). These findings indicate that ADMA is related to exacerbation of chronic CHF by suppression of the compensatory higher level of plasma NO.