3-nitrotyrosine and Vasculitis

The heme-containing enzyme myeloperoxidase (MPO) is both present and active in inflammatory conditions. This enzyme is potentiated by its formation of multiple inflammatory mediators. The two most common mediators are the modified tyrosines: nitrotyrosine and 3-chlorotyrosine. Along with other modified tyrosines, these molecules have been found to be elevated in atherosclerosis, lung disease, sepsis, vasculitis, and other inflammatory diseases. By treating some of these diseases, the levels of modified tyrosines have been shown to decrease. There have been a wide range of animal models designed to study the in vivo effects of these tyrosine molecules. In addition, there are also several reports in the literature of the in vitro actions of modified tyrosine molecules demonstrated by various cell-culture models. The purpose of this review is to evaluate the clinical significance and biological functions of these modified tyrosine molecules in atherosclerosis as well as a variety of other inflammatory conditions. It is timely information because of their association with diseases as well as lack of overview of their molecular actions. This review will focus on the formation, clinical significance, and animal and cell-culture models of these important molecules.

Topics: Animals; Atherosclerosis; Endothelium, Vascular; Humans; Oxidative Stress; Tyrosine; Vasculitis

Indirect evidence implicates endothelial dysfunction in the pathogenesis of vascular diseases associated with obstructive sleep apnea (OSA). We investigated directly whether dysfunction and inflammation occur in vivo in the vascular endothelium of patients with OSA. The effects of continuous positive airway pressure (CPAP) therapy on endothelial function and repair capacity were assessed.. Thirty-two patients with newly diagnosed OSA and 15 control subjects were studied. Proteins that regulate basal endothelial nitric oxide (NO) production (endothelial NO synthase [eNOS] and phosphorylated eNOS) and inflammation (cyclooxygenase-2 and inducible NOS) and markers of oxidative stress (nitrotyrosine) were quantified by immunofluorescence in freshly harvested venous endothelial cells before and after 4 weeks of CPAP therapy. Vascular reactivity was measured by flow-mediated dilation. Circulating endothelial progenitor cell levels were quantified to assess endothelial repair capacity. Baseline endothelial expression of eNOS and phosphorylated eNOS was reduced by 59% and 94%, respectively, in patients with OSA compared with control subjects. Expression of both nitrotyrosine and cyclooxygenase-2 was 5-fold greater in patients with OSA than in control subjects, whereas inducible NOS expression was 56% greater. Expression of eNOS and phosphorylated eNOS significantly increased, whereas expression of nitrotyrosine, cyclooxygenase-2, and inducible NOS significantly decreased in patients who adhered to CPAP > or = 4 hours daily. Baseline flow-mediated dilation and endothelial progenitor cell levels were lower in patients than in control subjects, and both significantly increased in patients who adhered to CPAP > or = 4 hours daily.. OSA directly affects the vascular endothelium by promoting inflammation and oxidative stress while decreasing NO availability and repair capacity. Effective CPAP therapy is associated with the reversal of these alterations.

Topics: Adult; Biomarkers; Continuous Positive Airway Pressure; Cyclooxygenase 2; Endothelium, Vascular; Female; Humans; Hypoxia; Male; Middle Aged; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Oxidative Stress; Severity of Illness Index; Sleep Apnea, Obstructive; Treatment Outcome; Tyrosine; Vasculitis; Vasodilation; Veins

Obstructive sleep apnea (OSA) in children is associated with cardiovascular morbidity such as systemic and pulmonary hypertension. However, it remains unclear whether endothelial dysfunction occurs in pediatric OSA and whether it is reversible on effective treatment of OSA.. Consecutive nonobese children (aged 6 to 11 years) who were diagnosed with OSA after overnight polysomnography and control children matched on the basis of age, gender, ethnicity, and body mass index underwent blood draw the next morning for soluble CD40 ligand, asymmetric dimethylarginine (ADMA), and nitrotyrosine levels, as well as 2 iterations of 60-second cuff-occlusion tests for assessment of endothelial function. These tests were repeated 4 to 6 months after adenotonsillectomy. OSA children showed blunted reperfusion kinetics after release of occlusion, which completely normalized in 20 of 26 patients after adenotonsillectomy. All 6 children in whom no improvements occurred had a strong family history of cardiovascular disease (versus 2 of the remaining 20 patients; P<0.04). Plasma nitrotyrosine and ADMA levels were similar in OSA and control children; however, soluble CD40 ligand levels were higher in OSA children and were reduced after treatment, particularly in those with normalized hyperemic responses.. Postocclusive hyperemia is consistently blunted in children with OSA, and such altered endothelial function is reversible 4 to 6 months after treatment, particularly if a family history of cardiovascular disease is not present. Although no evidence for either nitric oxide-dependent oxidative/nitrosative stress or for the increased presence of the circulating nitric oxide synthase inhibitor ADMA was found in children with OSA, soluble CD40 ligand levels were increased in OSA and reflected the changes in endothelial function after treatment.

Topics: Adenoidectomy; Arginine; Body Weight; CD40 Ligand; Child; Endothelium, Vascular; Female; Humans; Hyperemia; Hypoxia; Male; Nitric Oxide; Polysomnography; Sleep Apnea, Obstructive; Tonsillectomy; Tyrosine; Vasculitis

Topics: Endothelium, Vascular; Humans; NF-kappa B; Nitric Oxide Synthase Type III; Oxidative Stress; Smoking; Tobacco Smoke Pollution; Tyrosine; Vasculitis

Atherosclerosis is a chronic inflammatory vascular disease driven by the subendothelial accumulation of macrophages. The mechanism regulating the inflammatory response in macrophages during atherogenesis remains unclear. Because microRNAs (miRNAs) play a crucial role in cellular signaling by posttranscriptional regulation of gene expression, we studied the miRNA expression profiles during the progression of atherosclerosis.. Using an miRNA real-time polymerase chain reaction array, we found that macrophage-derived miR-342-5p and miR-155 are selectively upregulated in early atherosclerotic lesions in Apoe(-/-) mice. miR-342-5p directly targets Akt1 through its 3'-untranslated region. Akt1 suppression by miR-342-5p induces proinflammatory mediators such as Nos2 and II6 in macrophages via the upregulation of miR-155. The local application of an miR-342-5p antagomir inhibits the development of atherosclerosis in partially ligated carotid arteries. In atherosclerotic lesions, the miR-342-5p antagomir upregulated Akt1 expression and suppressed the expression of miR-155 and Nos2. This reduced Nos2 expression was associated with a diminished generation of nitrotyrosine in the plaques. Furthermore, systemic treatment with an inhibitor of miR-342-5p reduced the progression of atherosclerosis in the aorta of Apoe(-/-) mice.. Macrophage-derived miR-342-5p promotes atherosclerosis and enhances the inflammatory stimulation of macrophages by suppressing the Akt1-mediated inhibition of miR-155 expression. Therefore, targeting miR-342-5p may offer a promising strategy to treat atherosclerotic vascular disease.

Topics: Animals; Aortic Diseases; Apolipoproteins E; Atherosclerosis; Bone Morphogenetic Protein Receptors, Type II; Carotid Stenosis; Chemokine CCL2; DEAD-box RNA Helicases; Disease Progression; Gene Expression Regulation; Interleukin-6; Macrophage Activation; Macrophages; Mice; Mice, Knockout; MicroRNAs; Nitric Oxide Synthase Type II; Oligonucleotides; Proto-Oncogene Proteins c-akt; Ribonuclease III; RNA, Antisense; Signal Transduction; Tyrosine; Up-Regulation; Vasculitis

The molecular mechanisms of the atheroprotective effect evoked by hormone replacement therapy in postmenopausal women is not well known. Recently, we have demonstrated enhanced activity of the ubiquitin-proteasome system in human atherosclerotic plaques and evidenced that it is associated with inflammatory-induced plaque rupture. Therefore, we hypothesized that hormone replacement therapy may exert the cardioprotective effects modulating the ubiquitin-proteasome activity. To investigate this possibility, this study examined the differences in inflammatory infiltration, as well as ubiquitin-proteasome activity, between asymptomatic carotid plaques of postmenopausal women with and without concomitant hormone replacement therapy. Plaques were obtained from 20 postmenopausal women treated with hormone replacement therapy (current users) and 32 nontreated women (never-users) enlisted to undergo carotid endarterectomy for extracranial high-grade (>70%) internal carotid artery stenosis. Plaques were analyzed for macrophages, T lymphocytes, human leukocyte antigen-DR+ cells, ubiquitin-proteasome system, nuclear factor kappaB, inhibitor of nuclear factor kappaBbeta, tumor necrosis factor-alpha, nitrotyrosine, matrix metalloproteinase-9, and collagen content (immunohistochemistry and ELISA). Compared with plaques from current users, plaques from never-users had more macrophages, T lymphocytes, and human leukocyte antigen-DR+ cells (P<0.001); more ubiquitin-proteasome activity, tumor necrosis factor-alpha, and nuclear factor kappaB (P<0.001); and more nitrotyrosine and matrix metalloproteinase-9 (P<0.001), along with a lesser collagen content and inhibitor of nuclear factor kappaBbeta levels (P<0.001). This study supports the hypothesis that hormone replacement therapy inhibits plaque ubiquitin-proteasome activity by decreasing oxidative stress generation in postmenopausal women. This effect, in turn, might contribute to plaque stabilization by inhibiting the activation of nuclear factor kappaB-dependent inflammation, responsible for plaque rupture.

Topics: Aged; Carotid Arteries; Carotid Artery Diseases; Down-Regulation; Endarterectomy, Carotid; Estrogen Replacement Therapy; Female; Humans; Middle Aged; NF-kappa B; Oxidative Stress; Postmenopause; Preoperative Care; Proteasome Endopeptidase Complex; Superoxides; Tyrosine; Ubiquitin; Vasculitis

Chronic, inappropriate (relative to dietary Na+) elevations in circulating aldosterone, such as occur in congestive heart failure, are accompanied by a proinflammatory vascular phenotype involving the coronary and systemic vasculature. An immunostimulatory state with activated peripheral blood mononuclear cells (PBMCs) precedes this phenotype and is induced by a fall in cytosolic free [Mg2+]i and subsequent Ca2+ loading of these cells and transduced by oxidative/nitrosative stress.. We sought to further validate this hypothesis in rats with aldosterone/1%NaCl treatment (ALDOST) by using several interventions as cotreatment: a Mg2+-supplemented diet; amlodipine, a CCB; and N-acetylcysteine, an antioxidant. Blood samples were obtained at weeks 1 to 4 of ALDOST to monitor [Mg2+]i, [Ca2+]I, and H2O2 production in PBMCs. Coronal ventricular sections were examined for invading inflammatory cells and 3-nitrotyrosine labeling, a marker of oxidative/nitrosative stress. In response to ALDOST and compared with untreated controls, we found an early and persistent reduction in [Mg2+]i with a subsequent rise in [Ca2+]i and H2O2 production, each of which was either attenuated or abrogated by the Mg2+-supplemented diet and by N-acetylcysteine, whereas amlodipine prevented Ca2+ loading and an altered redox state. Cotreatment with these interventions either markedly attenuated or prevented the appearance of the proinflammatory coronary vascular phenotype and the presence of 3-nitrotyrosine in invading inflammatory cells.. We suggest that the immunostimulatory state that appears during aldosteronism and leads to a proinflammatory coronary vascular phenotype is induced by a fall in [Mg2+]i with Ca2+ loading of PBMCs and is transduced by H2O2 production in these cells.

Topics: Acetylcysteine; Amlodipine; Animals; Biomarkers; Body Weight; Calcium; Dietary Supplements; Hydrogen Peroxide; Hyperaldosteronism; Leukocytes, Mononuclear; Magnesium; Male; Oxidation-Reduction; Oxidative Stress; Phenotype; Rats; Rats, Sprague-Dawley; Sodium Chloride, Dietary; Tyrosine; Vasculitis

NO in vivo has both beneficial and nonbeneficial effects depending on site and concentration. Peroxynitrite, resulting from the reaction of NO with superoxide radical, causes cellular damage. Nitrotyrosine, end product of NO's toxic effects on cellular proteins, is a stable compound that can be used to detect evidence of harmful quantities of NO. We sought to detect nitrotyrosine in coronary arterioles of DBA/2 mice injected intraperitoneally with Lactobacillus casei cell wall. The inflammatory response induced occurred in perivascular fashion and involved mainly macrophages. It was variable according to time points, being severe on days 10 and 14 and mild to moderate on days 3 and 7. Few basal inflammatory cells appeared in controls injected with phosphate-buffered saline. Western immunoblots of homogenized hearts on days 10 and 14 demonstrated specific nitrated proteins. Immunohistochemistry of frozen sections of diseased hearts showed positive immunoreactivity for nitrotyrosine in coronary arterioles at the same time points. These findings were absent in the controls. We also determined the expression of inducible nitric oxide synthase (iNOS) in controls on days 10 and 14. iNOS colocalized with nitrotyrosine in perivascular macrophages and coronary arterioles of treated mice. Additionally, aneurysms were found on day 10 and intracardiac hemorrhage with consequent death on day 14. These observations supply evidence that NO through its reactive product, peroxynitrite, and its antigen/tissue marker, nitrotyrosine, is directly involved in coronary arteritis and aneurysm development in mice models of Kawasaki disease (KD). This article shows that macrophages are central to this and bolsters the likelihood of L. casei being the cause of KD.

Topics: Aneurysm; Animals; Blotting, Western; Cell Wall; Coronary Vessels; Disease Models, Animal; Hemorrhage; Immunohistochemistry; Inflammation; Lacticaseibacillus casei; Macrophages; Male; Mice; Mucocutaneous Lymph Node Syndrome; Myocardium; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Peroxynitrous Acid; Thrombosis; Time Factors; Tyrosine; Vasculitis