Differential effects of domoic acid and E. coli lipopolysaccharide on tumor necrosis factor-alpha, transforming growth factor-beta1 and matrix metalloproteinase-9 release by rat neonatal microglia: evaluation of the direct activation hypothesis.

The excitatory amino acid domoic acid is the causative agent of amnesic shellfish poisoning in humans. The in vitro effects of domoic acid on rat neonatal brain microglia were compared with E. coli lipopolysaccharide (LPS), a known activator of microglia mediator release over a 4 to 24 hour observation period.

New strategies in drug discovery.

Gene identification followed by determination of the expression of genes in a given disease and understanding of the function of the gene products is central to the drug discovery process. The ability to associate a specific gene with a disease can be attributed primarily to the extraordinary progress that has been made in the areas of gene sequencing and information technologies. Selection and validation of novel molecular targets have become of great importance in light of the abundance of new potential therapeutic drug targets that have emerged from human gene sequencing.

New developments in the use of beta-blockers for the management of heart failure.

Chronic heart failure (HF) has become a significant healthcare problem in the US. The number of new cases per year continues to grow steadily due to an ageing population and improved survival from acute coronary syndromes. As a consequence, the management of HF patients is of great importance.

Cathepsin S expression is up-regulated following balloon angioplasty in the hypercholesterolemic rabbit.

Objective: Neointimal development following balloon angioplasty involves many factors including smooth muscle cell (SMC) migration and proliferation and extracellular matrix (ECM) remodeling. Further, in hypercholesterolemic (HC) conditions, there is an influx of macrophage foam cells (FCs) into the restenotic lesion, which also involves degradation of the basement membrane and surrounding ECM. The ECM remodeling that occurs during restenosis has been shown to be mediated by various proteases.

Activation of peroxisome proliferator-activated receptor-alpha protects the heart from ischemia/reperfusion injury.

Background: Peroxisome proliferator-activated receptor-alpha (PPAR-alpha) is expressed in the heart and regulates genes involved in myocardial fatty acid oxidation (FAO). The role of PPAR-alpha in acute ischemia/reperfusion myocardial injury remains unclear.

Methods And Results: The coronary arteries of male mice were ligated for 30 minutes.

Structure of the C-terminally truncated human ProMMP9, a gelatin-binding matrix metalloproteinase.

The X-ray crystal structure of the proform of human matrix metalloproteinase MMP9 has been solved to 2.5 A resolution. The construct includes the prodomain, the catalytic domain and three FnII (fibronectin type II) domains.

Myocardial protection from ischemia/reperfusion injury by targeted deletion of matrix metalloproteinase-9.

Objective: Matrix metalloproteinase-9 (MMP-9) activity is up regulated in the heart subjected to ischemic insult. Whether increased MMP-9 activity contributes to acute myocardial injury after ischemia-reperfusion remains unknown. To investigate the role of MMP-9 in myocardial infarction, we utilized a MMP-9 knockout mouse.

Effect of a short-term in vitro exposure to the marine toxin domoic acid on viability, tumor necrosis factor-alpha, matrix metalloproteinase-9 and superoxide anion release by rat neonatal microglia.

Background: The excitatory amino acid domoic acid, a glutamate and kainic acid analog, is the causative agent of amnesic shellfish poisoning in humans. No studies to our knowledge have investigated the potential contribution to short-term neurotoxicity of the brain microglia, a cell type that constitutes circa 10% of the total glial population in the brain. We tested the hypothesis that a short-term in vitro exposure to domoic acid, might lead to the activation of rat neonatal microglia and the concomitant release of the putative neurotoxic mediators tumor necrosis factor-alpha (TNF-alpha), matrix metalloproteinases-2 and-9 (MMP-2 and -9) and superoxide anion (O2-).

Upregulated expression of human membrane type-5 matrix metalloproteinase in kidneys from diabetic patients.

Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that degrade the extracellular matrix (ECM). The membrane-type matrix metalloproteinases (MT-MMPs) are a new family of MMPs that differ from other MMPs in that they have a transmembrane domain that anchors them to the cell surface. MT-MMPs have been shown to function as receptors and activators for other MMPs and to localize extracellular matrix proteolysis at the pericellular region.

Matrix metalloproteinase expression in cardiac myocytes following myocardial infarction in the rabbit.

Myocardial infarction (MI), leads to cardiac remodeling, thinning of the ventricle wall, ventricular dilation, and heart failure, and is a leading cause of death. Interactions between the contractile elements of the cardiac myocytes and the extracellular matrix (ECM) help maintain myocyte alignment required for the structural and functional integrity of the heart. Following MI, reorganization of the ECM and the myocytes occurs, contributing to loss of heart function.

Metalloproteinase increases in the injured rat spinal cord.

Up-regulation of matrix metalloproteinases MMP-9 and MMP-2 after injury to the spinal cord (SCI) is demonstrated. MMP-9 activity maximized at 12-24 h, and MMP-2 rose at 5 days post-injury. MMP-3 was not detectable by zymographic analysis, so its level of expression was, at most, very low.

SB 239063, a p38 MAPK inhibitor, reduces neutrophilia, inflammatory cytokines, MMP-9, and fibrosis in lung.

The effects of a second generation p38 mitogen-activated protein kinase (MAPK) inhibitor, SB 239063 [trans-1-(4-hydroxycyclohexyl)-4-(4-fluorophenyl)-5-(2-methoxypyridim idi n-4-yl)imidazole; IC(50) = 44 nM vs. p38 alpha], were assessed in models that represent different pathological aspects of chronic obstructive pulmonary disease (COPD) [airway neutrophilia, enhanced cytokine formation and increased matrix metalloproteinase (MMP)-9 activity] and in a model of lung fibrosis. Airway neutrophil infiltration and interleukin (IL)-6 levels, assessed by bronchoalveolar lavage 48 h after lipopolysaccharide (LPS) inhalation, were inhibited dose dependently by 3-30 mg/kg of SB 239063 given orally twice a day.

Application of in vivo and ex vivo magnetic resonance imaging for evaluation of tranilast on neointima formation following balloon angioplasty of the rat carotid artery.

Objective: Recent studies suggest that tranilast inhibits a variety of agents implicated in neointimal growth and restenosis in experimental animal models and humans. We report here a study evaluating the efficacy of tranilast in the rat carotid artery balloon angioplasty model, a model that mimics many aspects of the percutaneous transluminal angioplasty procedure in humans. Efficacy was determined based on in vivo and ex vivo magnetic resonance imaging (MRI) as well as by histomorphometry.

Expression of interleukin-1beta, interleukin-1 receptor, and interleukin-1 receptor antagonist mRNA in rat carotid artery after balloon angioplasty.

Interleukin-1beta (IL-1beta) is a pleiotropic cytokine capable of inducing smooth muscle activation and leukocyte recruitment in restenosis and atherosclerosis. Our present study investigated the expression of IL-1beta, IL-1 receptor antagonist (IL-1ra), and IL-1 receptor (IL-1RI and IL-1RII) mRNA in carotid artery after balloon angioplasty using semiquantitative reverse transcription/polymerase chain reaction (RT/PCR) and Northern analysis. Time course studies revealed that IL-1beta mRNA was rapidly induced at 6 h (30-fold increase over control, P < 0.

Human urotensin-II is a potent vasoconstrictor and agonist for the orphan receptor GPR14.

Urotensin-II (U-II) is a vasoactive 'somatostatin-like' cyclic peptide which was originally isolated from fish spinal cords, and which has recently been cloned from man. Here we describe the identification of an orphan human G-protein-coupled receptor homologous to rat GPR14 and expressed predominantly in cardiovascular tissue, which functions as a U-II receptor. Goby and human U-II bind to recombinant human GPR14 with high affinity, and the binding is functionally coupled to calcium mobilization.

Escherichia coli lipopolysaccharide potentiation and inhibition of rat neonatal microglia superoxide anion generation: correlation with prior lactic dehydrogenase, nitric oxide, tumor necrosis factor-alpha, thromboxane B2, and metalloprotease release.

The effects of lipopolysaccharide (LPS) on the central nervous system, one of the first organs to be affected by sepsis, are still incompletely understood. Rat microglia (BMphi) constitute the main leukocyte-dependent source of reactive oxygen species in the central nervous system. The in vitro effect of LPS on agonist-stimulated superoxide (O2-) generation from BMphi appears controversial.

TL1, a novel tumor necrosis factor-like cytokine, induces apoptosis in endothelial cells. Involvement of activation of stress protein kinases (stress-activated protein kinase and p38 mitogen-activated protein kinase) and caspase-3-like protease.

TL1 is a recently discovered novel member of the tumor necrosis factor (TNF) cytokine family. TL1 is abundantly expressed in endothelial cells, but its function is not known. The present study was undertaken to explore whether TL1 induces apoptosis in endothelial cells and, if so, to explore its mechanism of action.

Factor XIIIa cross-links lipoprotein(a) with fibrinogen and is present in human atherosclerotic lesions.

During the development of atherosclerotic lesions, lipoprotein(a) [Lp(a)], a highly atherogenic lipoprotein, accumulates within fibrin clots attached to blood vessel walls. As Lp(a) accumulates within the fibrin clot with time, fatty streaks are formed that develop into occlusive atherosclerotic plaques. It is not understood, however, which mechanisms are involved in the binding of Lp(a) to fibrin and, hence, the stable incorporation of Lp(a) into the fibrin clot.

Matrix metalloproteinase expression increases after cerebral focal ischemia in rats: inhibition of matrix metalloproteinase-9 reduces infarct size.

Background And Purpose: Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that degrade the extracellular matrix and are implicated in numerous pathological conditions including atherosclerosis, inflammation, and tumor growth and metastasis. In the brain, the endothelial cell wall, strengthened by tight junctions, defines the blood-brain barrier (BBB). The extracellular matrix molecules constitute the basement membrane underlying the vasculature and play a critical role in maintaining the integrity of the BBB.

Staurosporine-induced apoptosis in cardiomyocytes: A potential role of caspase-3.

Cardiomyocyte apoptosis has been demonstrated in animal models of cardiac injury as well as in patients with congestive heart failure or acute myocardial infarction. Therefore, apoptosis has been proposed as an important process in cardiac remodeling and progression of myocardial dysfunction. However, the mechanisms underlying cardiac apoptosis are poorly understood.

Carvedilol inhibits endothelin-1 biosynthesis in cultured human coronary artery endothelial cells.

Carvedilol, a multiple action neurohumoral antagonist, has been reported recently to significantly reduce mortality in congestive heart failure (CHF) patients. In addition to being a beta-adrenoceptor antagonist, one of the unique aspects of the biological effects of carvedilol is that it is also a potent antioxidant with antimitogenic properties. As there is a significant correlation between plasma immunoreactive endothelin-1 (ET-1) levels and the severity of CHF, the present study was designed to determine the effects of carvedilol on ET-1 biosynthesis in cultured human coronary artery endothelial cells (HCAECs).

Possible involvement of stress-activated protein kinase signaling pathway and Fas receptor expression in prevention of ischemia/reperfusion-induced cardiomyocyte apoptosis by carvedilol.

Carvedilol, a new vasodilating beta-adrenoceptor antagonist and a potent antioxidant, produces a high degree of cardioprotection in a variety of experimental models of ischemic cardiac injury. Recent clinical studies in patients with heart failure have demonstrated that carvedilol reduces morbidity and mortality and inhibits cardiac remodeling. The present study was designed to explore whether the protective effects of carvedilol on the ischemic myocardium include inhibition of apoptosis of cardiomyocytes and, if so, to determine its mechanism of action.

T cell adhesion to endothelial cells and extracellular matrix is modulated upon transendothelial cell migration.

During inflammation, T cells transmigrate from the bloodstream into perivascular tissues. As T cells transmigrate, they undergo a series of attachments to and detachments from the endothelium and then extravasate into the extracellular matrix (ECM). T cell migration into the ECM involves a number of mechanisms that influence cell-ECM interactions.

Expression of 14-3-3 gamma in injured arteries and growth factor- and cytokine-stimulated human vascular smooth muscle cells.

One of the most critical cellular events in disease states such as vascular restenosis is the cytokine-induced activation of vascular smooth muscle cells (VSMCs) resulting in intimal thickening. Identification of the molecular mechanisms of VSMC activation is crucial in understanding the initiation of vascular restenosis. In this report, we show that one 14-3-3 protein family isoform, gamma, is transcriptionally up-regulated in rat carotid arteries after balloon angioplasty.

Cleavage of type I procollagen by C- and N-proteinases is more rapid if the substrate is aggregated with dextran sulfate or polyethylene glycol.

The enzymes procollagen C- and N-proteinases specifically cleave carboxyl- and amino-terminal propeptides of procollagens. After cleavage of the propeptides, the resulting collagens self-assemble into fibrils. In most previous experiments with the enzymes, the substrate was monomeric type I procollagen.