Genomics of foam cells and nonfoamy macrophages from rabbits identifies arginase-I as a differential regulator of nitric oxide production

OBJECTIVE - Conversion of macrophages to foam cells is a critical step in the initiation and progression of atherosclerosis. We sought to identify genes differentially regulated in foam cells, since these are likely to include new targets for intervention. METHODS AND RESULTS - We used suppression subtraction hybridization to compare foam cells and nonfoamy macrophages isolated from subcutaneous granulomas of rabbits fed a cholesterol-rich or normal chow diet and confirmed upregulation of 3 genes, including matrix metalloproteinase-12 (mRNA 2.0-fold,

Bivariate constant stress degradation model: Led lighting system reliability estimation with two-stage modelling

10.1002/qre.1022Quality and Reliability Engineering International2581067-1084QREI

Zoledronate upregulates MMP-9 and -13 in rat vascular smooth muscle cells by inducing oxidative stress

PubMed ID: 27143852Background: Bisphosphonates, including zoledronate, target osteoclasts and are widely used in the treatment of osteoporosis and other bone resorption diseases, despite side effects that include damaging the stomach epithelium. Beneficial and adverse effects on other organ systems, including the cardiovascular system, have also been described and could impact on the use of bisphosphonates as therapeutic agents. Vascular smooth muscle cells (VSMCs) are major constituents of the normal vascular wall and have a key role in intimal thickening and atherosclerosis, in part by secreting MMPs that remodel the extracellular matrix and cleave cell surface proteins or secreted mediators. In this study, we investigated the effects of zoledronate on MMP expression. Methods: Rat VSMCs were stimulated by PDGF (50 ng/mL) plus TNF-? (10 ng/mL) or left unstimulated for a further 24 hours in serum-free medium. In other series of experiments, cells were pre-treated either with SC-514 (50 µM) or with apocynin (20 nM) for 2 hours, then zoledronate (100 µM) was added into 2% fetal calf serum containing medium for 24 hours. Results and discussion: Using isolated rat VSMCs in culture, zoledronate (100 µM) increased MMP-9 and -13 mRNA expressions but inhibited MMP-2 expression. MMP-9 and MMP-13 up-regulation was shown to depend on the NF-?B pathway; and this was activated by zoledronate. Furthermore, zoledronate elevated the levels of reactive oxygen species detected by either dichlorofluorescein in isolated VSMCs or lucigenin enhanced chemiluminescence in rat aortic rings in vitro. Apocynin, an inhibitor of NADPH oxidase, reversed NF-?B activation and MMP-9 and MMP-13 up-regulation by zoledronate. Conclusion: We conclude that zoledronate increases MMP-9 and MMP-13 expressions in rat VSMCs dependent upon stimulation of the NF-?B pathway by reactive oxygen species. Effects on MMP expression may contribute to the pharmacologic profile of bisphosphonates. © 2016 Arun et al.British Heart Foundation: CH95/001 University of Bristol Ege ÜniversitesiThe authors would like to thank Dr Goksel Gokce, Ege University Faculty of Pharmacy and Dr Steve White, University of Bristol for valuable help and expertise on oxidative stress measurements. MZA would also like to thank Prof Levent Ustunes for kind help and encouragement. This study was supported by the British Heart Foundation grant CH95/001. -

Exogenous Hydrogen Sulfide Inhibits Superoxide Formation, NOX-1 Expression and Rac 1 Activity in Human Vascular Smooth Muscle Cells

The activity of NADPH oxidase (NOX) is blocked by nitric oxide (NO). Hydrogen sulfide (H(2)S) is also produced by blood vessels. It is reasonable to suggest that H(2)S may have similar actions to NO on NOX. In order to test this hypothesis, the effect of sodium hydrosulfide (NaHS) on O(2)(-) formation, the expression of NOX-1 (a catalytic subunit of NOX) and Rac(1) activity (essential for full NOX activity) in isolated vascular smooth muscle cells (hVSMCs) was investigated. hVSMCs were incubated with the thromboxane A(2) analogue U46619 +/- NaHS for 1 or 16 h, and O(2)(-) formation, NOX-1 expression and Rac(1) activity were assessed. The possible interaction between H(2)S and NO was also studied by using an NO synthase inhibitor, L-NAME, and an NO donor, DETA-NONOate. The role of K(ATP) channels was studied by using glibenclamide. NaHS inhibited O(2)(-) formation following incubation of 1 h (IC(50), 30 nM) and 16 h (IC(50), 20 nM), blocked NOX-1 expression and inhibited Rac(1) activity. These inhibitory effects of NaHS were mediated by the cAMP-protein-kinase-A axis. Exogenous H(2)S prevents NOX-driven intravascular oxidative stress through an a priori inhibition of Rac(1) and downregulation of NOX-1 protein expression, an effect mediated by activation of the adenylylcyclase-cAMP-protein-kinase-G system by H(2)S

A selective matrix metalloproteinase-12 inhibitor retards atherosclerotic plaque development in apolipoprotein E-knockout mice

Objective-: Matrix metalloproteinase (MMP)-12 has been implicated in plaque progression and instability and is also amenable to selective inhibition. In this study, we investigated the influence of a greater than 10-fold selective synthetic MMP-12 inhibitor on plaque progression in the apolipoprotein E knockout mouse model of atherosclerosis. Methods and Results-: A phosphinic peptide (RXP470.1) that is a potent, selective murine MMP-12 inhibitor significantly reduced atherosclerotic plaque cross-sectional area by approximately 50% at 4 different vascular sites in male and female apolipoprotein E knockout mice fed a Western diet. Furthermore, RXP470.1 treatment resulted in less complex plaques with increased smooth muscle cell:macrophage ratio, less macrophage apoptosis, increased cap thickness, smaller necrotic cores, and decreased incidence of calcification. Additional in vitro and in vivo findings indicate that attenuated monocyte/macrophage invasion and reduced macrophage apoptosis probably underlie the beneficial effects observed on atherosclerotic plaque progression with MMP-12 inhibitor treatment. Conclusion-: Our data demonstrate that a selective MMP-12 inhibitor retards atherosclerosis development and results in a more fibrous plaque phenotype in mice. Our study provides proof of principle to motivate translational work on MMP-12 inhibitor therapy in humans. Copyright © 2011 American Heart Association. All rights reserved