Involvement of NAD(P)H oxidase in the enhanced expression of cell adhesion molecules in the aorta of diabetic mice

The increased levels of cell adhesion molecules (CAM) have been identified in diabetic vasculatures, but the underlying mechanisms remain unclear. To determine the relationship among vascular production of superoxide, expression of CAM and diabetes, superoxide generation and expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E- and P-selectin in the aorta from control (C57BL/6J) and diabetic mice (ob/ob) were measured. In situ staining for superoxide using dihydroethidium showed an increased superoxide production in diabetic aorta in association with an enhanced NAD(P)H oxidase activity. Immunohistochemical analysis revealed that the endothelial expression of ICAM-1 (3.5 +/- 0.4) and VCAM-1 (3.8 +/- 0.3) in diabetic aorta was significantly higher than that in control aorta (0.9 +/- 0.5 and 1.6 +/- 0.3, respectively). Furthermore, there was a strong positive correlation (r = 0.89, p < 0.01 in ICAM-1 and r = 0.88, p < 0.01 in VCAM-1) between ICAM-1/VCAM-1 expression and vascular production of superoxide. The present data indicate that the increased production of superoxide via NAD(P)H oxidase may explain the enhanced expression of CAM in diabetic vasculatures.

Effects of statins on endothelium and signaling mechanisms

Endothelium dysfunction may result from increased production of reactive oxygen species and decreased availability of nitric oxide. Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (ie, statins) exert cholesterol-independent vasoprotective effects that are mediated, in part, through the inhibition of small G-proteins Rho and Rac. Rho negatively regulates endothelial nitric oxide synthase and Rac contributes to NAD(P)H-oxidase activation and superoxide production. Statins inhibit both Rho and Rac GTPase activity via inhibition of geranylgeranylation, which confers endothelial nitric oxide synthase upregulation and decreases superoxide production, respectively. Sudden discontinuation of statin therapy may have negative effects. Withdrawal of statin treatment leads to an overshoot activation of Rho and Rac with dramatic effects on nitric oxide bioavailability, NAD(P)H-oxidase activity, and superoxide production.

Circulating mononuclear cells in the obese are in a proinflammatory state

BACKGROUND

In view of the increase in plasma concentrations of proinflammatory mediators tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and C-reactive protein (CRP) in obesity, we investigated whether peripheral blood mononuclear cells (MNC) from obese subjects are in a proinflammatory state.

METHODS AND RESULTS

MNC were prepared from fasting blood samples of obese (n=16; body mass index [BMI]=37.7+/-5.0 kg/m2) and normal-weight control (n=16; BMI=23.8+/-1.9 kg/m2) subjects. Nuclear factor kappaB (NF-kappaB) binding to DNA in nuclear extracts was elevated (P<0.05) and the inhibitor of NFkappaB-beta (IkappaB-beta) was significantly lower (P<0.001) in the obese group. Reverse transcription-polymerase chain reaction revealed elevated levels of migration inhibitor factor (MIF), IL-6, TNF-alpha, and matrix metalloproteinase-9 (MMP-9) mRNA expression in the obese subjects (P<0.05). Plasma concentrations of MIF, IL-6, TNF-alpha, MMP-9, and CRP were also significantly higher. Plasma glucose, insulin, and free fatty acids (FFAs) were measured, and homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. Plasma FFA concentration related significantly to BMI, IL-6, and TNF-alpha mRNA expression and plasma CRP levels but not to HOMA-IR. On the other hand, the inflammatory mediators were significantly related to BMI and HOMA-IR.

CONCLUSIONS

These data show (1) for the first time that MNC in obesity are in a proinflammatory state with an increase in intranuclear NF-kappaB binding, a decrease in IkappaB-beta, and an increase in the transcription of proinflammatory genes regulated by NF-kappaB; (2) that plasma FFAs are a modulator of inflammation; and (3) that insulin resistance is a function of inflammatory mediators.

[Autosomal chronic granulomatous disease: case report and mutation analysis of two Brazilian siblings]

OBJECTIVE

To report the case of two siblings with chronic granulomatous disease. Chronic granulomatous disease is a primary immunodeficiency disorder characterized by abnormal microbicidal activity. Mutations in the p47-phox gene (NCF-1) are present in about 30% of the patients with chronic granulomatous disease; this group presents a better prognosis and later onset of recurrent infections as compared with the X-linked variant, present in about 56% of patients.

DESCRIPTION

Case 1 is a female presenting repeat infections since age 10, starting with impetigo followed by severe pneumonia six months later. The severity of the lung infection associated with liver abscess and the patient's resistance to treatment prompted laboratory investigation for immunodeficiency. The results of the nitroblue tetrazolium and superoxide release tests were consistent with a diagnosis of chronic granulomatous disease. The parents and siblings were assessed, revealing the presence of granulomatous disease in a brother (Case 2). He also presented repeat infections with impetigo at age 10, followed by pneumonia six months later, however in a non severe form. Single-strand conformational polymorphism analysis detected abnormal electrophoretic mobility of exon 2 of the NCF-1 gene. Sequence DNA analysis revealed a dinucleotide GT deletion in exon 2.

COMMENTS

It is important to evaluate the relatives of chronic granulomatous disease patients, even in the absence of typical clinical signs. Defining the mutation and its correlation with phenotype is important to provide appropriate genetic counseling and clinical prognosis.

Enhanced autoimmunity, arthritis, and encephalomyelitis in mice with a reduced oxidative burst due to a mutation in the Ncf1 gene

The Ncf1 gene was recently identified as a strong regulator of severe arthritis in rat. This finding was surprising, because the disease-promoting allele mediated a lower level of reactive oxygen species in NADPH oxidase-expressing cells. We have now investigated a splice mutation of the Ncf1 gene in B10.Q mice, causing a truncated and nonfunctional Ncf1 protein. We found that the mutated Ncf1 led to a more severe and chronic relapsing collagen-induced arthritis. Enhanced IgG and delayed-type hypersensitivity responses against type II collagen were seen, indicating increased activity of autoreactive T cells. Interestingly, female Ncf1-mutated mice spontaneously developed severe arthritis during the postpartum period. The arthritis was accompanied by an increased antibody response to type II collagen, with the same fine specificity as in collagen-induced arthritis. The enhancing effect of the mutated Ncf1 could also be shown to be more general in that it enhanced myelin oligodendrocyte glycoprotein protein-induced experimental autoimmune encephalomyelitis, a model for multiple sclerosis. These results show that Ncf1, a gene important for oxidative burst, regulates the susceptibility and severity of both arthritis and encephalomyelitis and modulates, directly or indirectly, the level of T cell-dependent autoimmune responses.

Chronic granulomatous disease caused by a deficiency in p47(phox) mimicking Crohn's disease

We describe 2 cases of autosomal recessive chronic granulomatous disease (CGD) in 2 sisters presenting with a picture consistent with inflammatory bowel disease. The index case is a 10-year-old girl with a history of refractory Crohn's colitis treated with aggressive immunosuppressive therapy whose course subsequently was complicated by central nervous system aspergillosis. Additional evaluation showed a diagnosis of CGD, an underlying immunodeficiency in which phagocytes fail to produce microbicidal reactive oxygen intermediates because of inherited defects in the reduced form of nicotinamide-adenine phosphate dinucleotide (NADPH) oxidase. The diagnosis of a typically X-linked inherited disease in our female patient suggested that she had 1 of the 3 less common autosomal recessive forms of the disease. This was confirmed by studies showing the absence of the p47(phox) subunit of NADPH oxidase in her neutrophils and the presence of a homozygous dinucleotide deletion in the neutrophil cytosolic factor 1 gene that encodes p47(phox). Additional analyses of members of the patient's immediate family showed the same homozygous mutation in 2 siblings, 1 of whom also developed chronic colitis consistent with a diagnosis of Crohn's disease. These 2 cases emphasize the importance of high clinical suspicion for an alternative diagnosis of immune deficiency in the setting of presumed inflammatory bowel disease and opportunistic infection.

Adrenomedullin Administration Immediately After Myocardial Infarction Ameliorates Progression of Heart Failure in Rats

Background— Adrenomedullin (AM) is expressed in cardiac tissue, and plasma AM levels increase in patients with acute myocardial infarction (MI). This study was performed to determine whether AM administration immediately after acute MI inhibits progression of heart failure in rats.

Methods and Results— Rats were infused with 1.0 μg/h IP AM or saline over 7 days immediately after MI inducted by left coronary ligation and were examined 9 weeks after MI. Compared with the saline infusion, AM infusion significantly improved survival (59% versus 81%; P <0.05) and body weight gain (32%; P <0.01) and reduced heart weight (−28%; P <0.01), lung weight (−26%; P <0.01), left ventricular (LV) end-diastolic pressure (11.4±2.0 versus 4.0±0.6 mm Hg, mean± SEM; P <0.01), collagen volume fraction of noninfarcted LV (−39%; P <0.05), and plasma levels of endogenous rat AM (−38%; P <0.05) without affecting infarct size. To investigate the mechanism of AM actions, another series of MI rats infused with AM were killed on day 7. AM infusion had no effect on organ weights and hemodynamic parameters on day 7 of MI but significantly reduced urinary excretion of isoprostane (−61%; P <0.01) and noninfarcted LV mRNA levels of ACE (−31%; P <0.05) and p22-phox (−30%; P <0.05).

Conclusions— AM administration during the early period of MI improved the survival and ameliorated progression of LV remodeling and heart failure. This beneficial effect was accompanied by reductions in oxidative stress and ACE mRNA expression in noninfarcted LV in the AM infusion period.

Effects of glucocorticoids on the respiratory burst of Chlamydia-primed THP-1 cells

We previously observed that the respiratory burst of human monocytes (THP-1 cell line) triggered by phorbol myristate acetate was strongly enhanced by a priming of the cells by Chlamydia pneumoniae [Biochem. Biophys. Res. Commun. 287 (2001) 781]. We describe here the modifications of the responses of Chlamydia-primed THP-1 cells to hydrocortisone (HCT) and methylprednisolone (MPL). HCT and MPL inhibited the production of the cytokines TNFalpha and IL-8. But HCT, which inhibited the respiratory burst in LPS-primed monocytes, paradoxically stimulated the phenomenon in Chlamydia-primed cells; MPL exerted no significant effect. Both glucocorticoids did not significantly modify the triggering effect of Chlamydia on NF-kappaB binding activity. On the expression of p22(phox), a protein subunit of the NADPH oxidase, HCT had an increasing and MPL a decreasing effect. Glucocorticoids thus had unexpected effects on the inflammatory response of Chlamydia-primed monocytes.

Effect of manidipine on gene expression and protein level of oxidative stress-related proteins: p22phox and HO-1: relevance for antihypertensive and anti-remodeling effects

Oxidative stress (OxSt) is a major damaging factor in arterial hypertension and its long-term complications. This is why considerable attention is paid to the possible effects of antihypertensive drugs on OxSt. Manidipine is a dihydropiridine calcium channel blocker with reported nephroprotective activities, but no information is available on its effect on OxSt and related mechanisms. This study assessed the effect of manidipine on normal subjects' monocyte gene and protein expression of OxSt-related proteins such as p22(phox), a NAD(P)H oxidase system subunit, critical in generating O2-, and heme oxygenase-1 (HO-1), induced by and protective from OxSt, and compared manidipine with the ACE inhibitor captopril and the calcium channel blocker nifedipine, in the presence and absence of sodium arsenite (NaAsO2) as an inducer of OxSt.Co-incubation of manidipine with NaAsO2 dose-dependently decreased p22(phox) mRNA production from basal: 0.87 +/- 0.1 d.u., 0.69 +/- 0.06 and 0.66 +/- 0.09 at 100, 300 and 500 nM respectively versus 0.99 +/- 0.2, P < 0.04, while HO-1 mRNA production was increased by the same concentrations of the drug: 0.87 +/- 0.1 d.u., 0.92 +/- 0.1, 0.98 +/- 0.1 respectively versus 0.63 +/- 0.07; P < 0.03. Monocyte p22(phox) mRNA production was reduced both by manidipine and captopril: 0.48 +/- 0.04 d.u. and 0.43 +/- 0.08, respectively versus 0.58 +/- 0.07, P < 0.006, while no changes were induced by nifedipine (0.61 +/- 0.07, P = ns). Manidipine increased monocyte HO-1 mRNA production (1.6 +/- 0.4 versus 1.2 +/- 0.4, P < 0.008), while nifedipine and captopril showed no effect (1.2 +/- 0.3 and 1.1 +/- 0.3, respectively). The effects of M on p22(phox) and HO-1 gene expression in the presence of OxSt were also paralleled by the same effects at protein level. In conclusion, manidipine decreases p22(phox) and increases HO-1 mRNA production and protein level. The manidipine-induced increase of HO-1 gene and protein expression seems to be a peculiar effect of this drug since it is not observed with captopril and nifedipine. This effect, together with the reduction of p22(phox) mRNA production, could play a role in its protective mechanism against OxSt.

Betaxolol stimulates eNOS production associated with LOX-1 and VEGF in Dahl salt-sensitive rats

OBJECTIVE

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) and vascular endothelial growth factor (VEGF) may play key roles in atherosclerosis, and have been shown to regulate nitric oxide (NO) production. However, the molecular mechanisms by which betaxolol, a specific beta 1-antagonist, stimulates endothelial NO synthase (eNOS) expression associated with LOX-1 and VEGF are unclear. We hypothesized that in the left ventricle of Dahl salt-sensitive (DS) rats, betaxolol reduces production of LOX-1 by suppressing NAD(P)H oxidase p47phox expression; betaxolol stimulates eNOS production associated with expression of VEGF and LOX-1; and betaxolol inhibits adhesion molecule and signal transduction, which may be involved in cardiovascular remodeling.

METHODS

After 5 weeks of feeding an 8% NaCl diet to 6-week-old DS rats (i.e. at 11 weeks of age), a distinct stage of concentric left ventricular hypertrophy was noted. Betaxolol (0.9 mg/kg per day) was administered to 6-week-old DS rats for 5 weeks until the onset of left ventricular hypertrophy stage.

RESULTS

Decreased expression of eNOS and VEGF in DS rats was increased by betaxolol. Upregulated LOX-1, NAD(P)H oxidase p47phox, intercellular and vascular cell adhesion molecule-1 expression and phosphorylations of p38 mitogen-activated protein kinase and p65 nuclear factor-kappa B activity were inhibited by betaxolol. Betaxolol administration resulted in significant improvement of cardiovascular remodeling and suppression of transforming growth factor-beta 1 and type I collagen expression.

CONCLUSIONS

These results suggest that cardioprotective effects of betaxolol may stimulate eNOS production associated with VEGF and LOX-1, and inhibit adhesion molecule and signal transduction in DS rats.

Vascular endothelial dysfunction and superoxide anion production in heart failure are p38 MAP kinase-dependent

OBJECTIVE

The mitogen-activated protein (MAP) kinase system, especially the p38 MAP kinase, is activated in chronic heart failure (CHF). However, the role of vascular p38 MAP kinase in CHF has not been analyzed yet.

METHODS AND RESULTS

In aortic rings from rats with CHF 10 weeks after myocardial infarction, acetylcholine-induced relaxation was attenuated (maximum relaxation, Rmax: 54+/-5%) compared to sham-operated animals (Rmax: 77+/-5%, p<0.01), while endothelium-independent relaxation elicited by sodium nitroprusside was not significantly changed. Aortic levels of phosphorylated p38 MAP kinase protein were significantly elevated in rats with CHF. In addition, phosphorylation of MAP kinase-activated protein kinase-2 (MAPKAPK-2), an index of p38 MAP kinase activity, was increased. Aortic superoxide anion generation was significantly enhanced in rats with CHF accompanied by elevation of the NAD(P)H oxidase subunit p47phox protein expression. Inhibition of p38 MAP kinase by treatment with the p38 MAP kinase inhibitor SB239063 (800 ppm in standard rat chow) reduced MAPKAPK-2 phosphorylation, preserved acetylcholine-induced relaxation (Rmax: 80+/-4%, p<0.01), and reduced vascular superoxide formation. SB239063 treatment did not affect blood pressure and left ventricular enddiastolic pressure. In aortic tissue from CHF animals treated with the angiotensin-converting enzyme (ACE) inhibitor trandolapril, p38 MAP kinase phosphorylation was significantly reduced.

CONCLUSIONS

Vascular p38 MAP kinase is markedly activated in rats with CHF. Chronic p38 MAP kinase inhibition with SB239063 prevented endothelial vasomotor dysfunction through reduction of superoxide anion production.

Effect of three triterpenoid compounds isolated from root bark of Aralia elata on stimulus-induced superoxide generation and tyrosyl phosphorylation and translocation of p47(phox) and p67(phox) to cell membrane in human neutrophil

BACKGROUND

Root bark of Aralia elata is used as a folk medicine for neurasthenia, rheumatism, diabetes, hepatitis virus and spasm of the stomach in China, Japan and Russia.

METHODS

The effect of three triterpenoid compounds isolated from root bark of A. elata on stimulus-induced superoxide generation and tyrosyl phosphorylation and translocation of p47(phox) and p67(phox) to cell membrane was investigated. The three compounds examined were Elatoside A, Elatoside C, and Tarasaponin V.

RESULTS

When the cells were preincubated with these compounds, the superoxide generation induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP) was suppressed in a low concentration range. However, the superoxide generation was significantly enhanced by 40 micromol/l triterpenoid, and was again suppressed in the higher concentration range. In the case of superoxide generation induced by phorbol 12-myristate 13-acetate (PMA), the compounds had no obvious effect on the superoxide generation in low concentration but suppressed that at 40 micromol/l. These compounds also efficiently suppressed the superoxide generation induced by arachidonic acid (AA) at 10 micromol/l. In parallel to the effect on the fMLP-induced superoxide generation, these compounds suppressed fMLP-induced tyrosyl phosphorylation and the translocation to membrane of cytosolic compounds, p47(phox) and p67(phox) at 10 and 80 micromol/l but not at 40 micromol/l.

CONCLUSIONS

Triterpenoid saponins examined in this study effect stimulus-induced superoxide generation and tyrosyl phosphorylation and translocation to membrane of p47(phox) and p67(phox) in a concentration-dependent manner, and may have some pharmaceutical applications.

Angiotensin-converting enzyme and p22phox polymorphisms and the risk of coronary heart disease in a low-risk Spanish population

OBJECTIVE

To evaluate the genetic contribution to myocardial infarction in a homogeneous Caucasian population (a Mediterranean Spanish population) with very low frequency of coronary heart disease (CHD).

DESIGN

We analyzed a total of 210 subjects, younger than 55 years, considered to be a low-risk population (104 cases of myocardial infarction and 106 control), and genotyped them (using polymerase chain reaction and sequencing) for the angiotensin-converting enzyme (ACE) insertion/deletion (ACE I/D) and for the C242T polymorphism of NADPH oxidase p22(phox). Also, we sequenced 23 alleles of the ACE gene (9 D and 14 I) for the region that includes the end of the intron 16 and the exon 17.

RESULTS

The ACE genotype-prevalence values for II, ID and DD were 4.81%, 28.85% and 66.34%, respectively, among the myocardial infarction patients, and 2.83%, 71.70% and 25.47% among controls. The statistical analysis comparing patients and controls revealed significant differences (chi(2)=25.09, P=0.00000055) between the two subpopulations. Also, we found a strong association between the genotype DD and the risk of suffering CHD (odds ratio (OR): 3.64; 95% CI: 2.37-8.07). The prevalence of the CC, TC and TT genotypes of p22(phox) gene among healthy controls proved to be 53.77%, 44.34% and 1.89%, while those of myocardial infarction were 58.65%, 39.42% and 1.93%, respectively. The association of C242T polymorphism of the p22(phox) gene with CHD was not statistically significant, (chi(2)=0.49, P=0.48). Logistic-regression analysis demonstrated that the independent risk factor for developing myocardial infarction was the DD genotype of ACE gene. Finally, our results indicate that alleles I and D of ACE gene are differentiated at three positions (nucleotide sites 14,480, 14,488 and 14,521) of which, the positions 14,480 and 14,488 were in absolute linkage disequilibrium.

CONCLUSIONS

Among subjects of a Mediterranean population with low risk for CHD, the presence of DD ACE genotype could be a risk factor for myocardial infarction, and we confirm the linkage disequilibrium between two nucleotide positions of the ACE gene and the polymorphism for an Alu insertion.

Enhancer-deleted retroviral vectors restore high levels of superoxide generation in a mouse model of CGD

BACKGROUND

Retroviral vectors possess many advantages for use in gene therapy protocols, especially within the haematopoietic system. A number of attendant problems, however, still limit their safety in clinical application. The effects of the enhancer present in the retroviral long terminal repeat (LTR) are a major concern for the clinical usage of such vectors, as they can exert a powerful regulatory influence on the genes that surround them.

METHODS

To improve the safety and widen the applicability of retroviral vectors for use in gene therapy we have developed an enhancer-deleted (Delta-LTR) retroviral vector that retained high titre and demonstrated transcriptional activity in myeloid cells.

RESULTS

When used to correct a mouse model of autosomal recessive chronic granulomatous disease, the Delta-LTR vectors gave acceptable levels of gene transfer to mouse bone marrow cells. Evidence for a slight preferential expression in myeloid cells was obtained with all the vectors studied. Nitroblue tetrazolium assay of superoxide generation in mouse bone marrow derived haematopoietic colonies revealed that transduction with Delta-LTR vectors could restore functional NADPH oxidase to cells from these animals. Superoxide assay of peripheral blood confirmed that, although relatively low numbers of cells were transduced, the Delta-LTR vector was capable of reconstituting very high levels of oxidase activity, comparable to that obtained from normal cells.

CONCLUSIONS

The Delta-LTR vector described here could provide the basis for a new generation of retroviral vectors with improved safety.

Endothelium-derived microparticles impair endothelial function in vitro

Endothelial cell dysfunction (ECD) is emerging as the common denominator for diverse and highly prevalent cardiovascular diseases. Recently, an increased number of procoagulant circulating endothelial microparticles (EMPs) has been identified in patients with acute myocardial ischemia, preeclampsia, and diabetes, which suggests that these particles represent a surrogate marker of ECD. Our previous studies showed procoagulant potential of endothelial microparticles and mobilization of microparticles by PAI-1. The aim of this study was to test the effects of isolated EMPs on the vascular endothelium. EMPs impaired ACh-induced vasorelaxation and nitric oxide production by aortic rings obtained from Sprague-Dawley rats in a concentration-dependent manner. This effect was accompanied by increased superoxide production by aortic rings and cultured endothelial cells that were coincubated with EMPs and was inhibited by a SOD mimetic and blunted by an endothelial nitric oxide synthase inhibitor. Superoxide was also produced by isolated EMP. In addition, p22(phox) subunit of NADPH-oxidase was detected in EMP. Our data strongly suggest that circulating EMPs directly affect the endothelium and thus not only act as a marker for ECD but also aggravate preexisting ECD.

Targeting of the dual oxidase 2 N-terminal region to the plasma membrane

Dual oxidase 2 (Duox2) is a cell surface glycoprotein that probably provides thyroperoxidase with the H2O2 required to catalyze thyroid hormone synthesis. No functional H2O2-generating system has yet been obtained after transfecting Duox2 into non-thyroid cell lines, because it is retained in the endoplasmic reticulum (ER). We investigated the level of maturation of various Duox2 truncated proteins in an attempt to identify the region of Duox2 responsible for its remaining in the ER. Duox2-Q686X mutant, corresponding to the N-terminal ectodomain including the first putative transmembrane domain, was expressed in different cell lines. Carbohydrate content analysis revealed that complex type-specific Golgi apparatus (GA) oligosaccharides were present on pig Duox2-Q686X, whereas human truncated Duox2 carried only high mannose-type sugar chains characteristic of the ER. Further characterization using surface biotinylation and flow cytometry assays indicated that pig Duox2-Q686X was present at the plasma membrane, whereas human Duox2-Q686X remained inside the cell. The replacement of the last 90 residues of the human Duox2-Q686X with the pig equivalent region allowed the chimerical peptide to reach the Golgi apparatus. Pig mutants containing the complete first intracellular loop with or without the second transmembrane domain accumulated in the ER. These findings show that 1) the human Duox2-Q686X region encompassing residues 596-685 prevents mutant exportation from the ER and 2) there is a pig Duox2 retention domain in the first intracellular loop. In addition, missense mutations of four cysteines (Cys-351, -370, -568, or -582) completely inhibited the emergence of pig Duox2-Q686X from the ER compartment, indicating their importance in Duox2 maturation.

p38 MAPK associated with stereoselective priming by grepafloxacin on O2- production in neutrophils

Grepafloxacin is an asymmetric fluoroquinolone derivative which possesses high tissue penetrability as well as strong, broad-spectrum antimicrobial activities. We recently found that grepafloxacin induced a priming effect on neutrophil respiratory burst induced by N-formylmethionylleucylphenylalanine. In this report, we elucidate the precise mechanism of the priming by grepafloxacin. The R(+) enantiomer of grepafloxacin induced a more potent priming effect than did S(-)-grepafloxacin. R(+)-Grepafloxacin also produced a more potent translocation of both p47- and p67-phox proteins to membrane fractions of neutrophils. Grepafloxacin-induced primed superoxide generation was significantly inhibited by pretreatment with PD169316 and SB203580, p38 mitogen-activated protein kinase (MAPK) inhibitors, but not with PD98059, a specific inhibitor of the upstream kinase that activates p44/42 MAPK, or SP600125, an inhibitor of stress-activated protein kinase/c-Jun N-terminal kinase (JNK). Grepafloxacin strongly phosphorylated p38 MAP kinase but not p44/42 MAPK or JNK. R(+)-Grepafloxacin showed more potent phosphorylation of p38 MAPK than did S(-)-grepafloxacin, in a time- and concentration-dependent manner. PD169316 significantly inhibited R(+)-grepafloxacin-induced translocation of p47-phox protein to the membrane fraction. Interestingly, grepafloxacin stereospecifically bound to the membrane fractions of neutrophils. These results strongly suggest that grepafloxacin stereospecifically primes neutrophil respiratory burst, and p38 MAPK activation is closely related to the grepafloxacin priming.

Simvastatin Prevents Load-Induced Protein Tyrosine Nitration in Overloaded Hearts

Hydroxymethylglutaryl-coenzyme A reductase inhibitors prevent load-induced left ventricular hypertrophy (LVH). Whether this effect is related to antioxidant properties of this class of drugs is poorly understood. The aim of the present report was to evaluate the regulation of nitrotyrosine production during the development of load-induced LVH and the effect of simvastatin treatment in this process. Rats were subjected to aortic constriction up to 15 days. LVH was evaluated by left/right ventricle mass ratio. Myocardial content of nitrotyrosine, nitric oxide synthase (NOS) isoforms, and phagocyte-type NAD(P)H-oxidase subunits (p67-phox and p22-phox) were analyzed by immunoblotting and immunohistochemistry assays. Another group of rats received treatment with either simvastatin or placebo for 15 days after the onset of pressure overload, and their hearts were also studied. Myocardial nitrotyrosine content was increased from 3 to 15 days of pressure overload in regions of cardiac myocytes in close apposition to myocardial stroma during LVH. Neuronal NOS (nNOS), inducible NOS (iNOS), and endothelial NOS (eNOS) isoforms had their expression increased in coronary vessels (nNOS and iNOS) and in myocardial stroma (eNOS) from day 3 to day 7 of aortic constriction. However, p67-phox and p22-phox expression was increased in cells of myocardial stroma in parallel to augmented myocardial nitrotyrosine content. Simvastatin treatment inhibited the increases in myocardial nitrotyrosine content and in p67-phox and p22-phox expression, and significantly reduced LVH. In conclusion, antioxidant properties of simvastatin might play a role in myocardial remodeling induced by pressure overload.

The effects of iron dextran on the oxidative stress in cardiovascular tissues of rats with chronic renal failure

BACKGROUND

Redox-active iron can promote oxidative stress and tissue injury by catalyzing hydroxyl radical generation and lipid peroxidation. Intravenous iron preparations are routinely administered in conjunction with erythropoietin to treat anemia in patients with chronic renal failure (CRF), a condition that is marked by oxidative stress and inflammation. This treatment frequently elevates iron burden, which can potentially intensify oxidative stress and, thus, cardiovascular disease in this population.

METHODS

We studied renal function and oxidative stress parameters in the cardiovascular tissues of CRF (5/6 nephrectomized) and sham-operated control rats 3 months after a single intravenous infusion of iron dextran (500 mg/kg).

RESULTS

Arterial pressure was equally elevated and creatinine clearance was equally reduced in both iron-treated and -untreated CRF groups. Iron administration significantly raised the blood hemoglobin, serum iron concentration, and transferrin saturation in both CRF and control groups. Iron administration resulted in a significant rise in plasma concentration of lipid peroxidation product, malondialdehyde in the CRF rats, and an insignificant rise in the control group. Plasma oxidized low-density lipoprotein (LDL) concentration was increased in the CRF groups, and was not affected by iron administrations. Iron administration raised nitrotyrosine abundance in the aorta of CRF but not in the control group. Left ventricular tissue abundance of p22(phox) subunit of NAD(P)H oxidase was elevated in CRF group and was not affected, whereas p67(phox) subunit abundance was raised by prior iron administration. Iron administration insignificantly lowered aorta p22(phox), but had no effect on p67(phox) subunit abundance in the treated CRF group. Previous iron administration significantly lowered superoxide dismutase and catalase abundance in the aorta and glutathione peroxidase in the left ventricle of CRF animals, but did not significantly change these parameters in the iron-treated control animals.

CONCLUSION

A single intravenous injection of iron dextran increased oxidative stress in the cardiovascular tissues in the CRF group, but not the control rats, pointing to heightened susceptibility to iron-mediated toxicity in CRF. However, administration of iron dextran did not adversely affect kidney function, and favorably affected hemoglobin concentration in rats with CRF induced by renal mass reduction. Further studies are needed to explore the effects of other parenteral iron preparations, repeated intravenous iron administration, and presence of comorbid conditions such as diabetes.

Insulin generates free radicals by an NAD(P)H, phosphatidylinositol 3'-kinase-dependent mechanism in human skin fibroblasts ex vivo

Oxidative stress may be involved in the development of vascular complications associated with diabetes; however, the molecular mechanism responsible for increased production of free radicals in diabetes remains uncertain. Therefore, we examined whether acute hyperinsulinemia increases the production of free radicals and whether this condition affects proliferative extracellular signal-regulated kinase (ERK-1 and -2) signaling in human fibroblasts in vitro. Insulin treatment significantly increased intracellular superoxide anion (O(2)(-)) production, an effect completely abolished by Tiron, a cell-permeable superoxide dismutase (SOD) mimetic and by polyethylene glycol (PEG)-SOD, but not by PEG catalase. Furthermore, insulin-induced O(2)(-) production was attenuated by the NAD(P)H inhibitor apocynin, but not by rotenone or oxypurinol. Inhibition of the phosphatidylinositol 3'-kinase (PI 3'-kinase) pathway with LY294002 blocked insulin-stimulated O(2)(-) production, suggesting a direct involvement of PI 3'-kinase in the activation of NAD(P)H oxidase. The insulin-induced free radical production led to membranous translocation of p47phox and markedly enhanced ERK-1 and -2 activation in human fibroblasts. In conclusion, these findings provided direct evidence that elevated insulin levels generate O(2)(-) by an NAD(P)H-dependent mechanism that involves the activation of PI 3'-kinase and stimulates ERK-1- and ERK-2-dependent pathways. This effect of insulin may contribute to the pathogenesis and progression of cardiovascular disease in the insulin resistance syndrome.

Platelet-derived exosomes of septic individuals possess proapoptotic NAD(P)H oxidase activity: A novel vascular redox pathway

OBJECTIVE

Vascular dysfunction in sepsis may involve apoptosis of vascular cells through redox signaling mechanisms, which are still poorly investigated. Platelets have been shown to produce reactive oxygen species and to release microparticles, related to thrombotic and inflammatory processes. The present study was undertaken to investigate whether, in severe sepsis, platelet-derived microparticles could produce reactive oxygen species through a phagocyte-type nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and if such particles may induce vascular cell apoptosis through a reactive oxygen species-dependent mechanism.

DESIGN

Experimental study.

SETTING

Molecular and cell biology laboratories related to tertiary hospitals.

SUBJECTS

Microparticles obtained from septic patients and from healthy individuals were investigated concerning their biochemical properties and their effects on vascular endothelial and smooth muscle cells in culture.

INTERVENTIONS

Microparticle surface antigens were studied by flow cytometry and the presence of NADPH oxidase subunits by Western blot analysis. Microparticle reactive oxygen species generation was investigated through superoxide dismutase-inhibitable cytochrome c reduction and 5 microM lucigenin chemiluminescence. The effects of microparticles on vascular cell apoptosis rates were analyzed by immunofluorescence microscopy based on annexin V-fluorescein 5(6)-isothiocyanate assay.

MEASUREMENTS AND MAIN RESULTS

Flow cytometry analysis of microparticles obtained from septic patients and healthy individuals showed a surface antigenic pattern similar to exosomes and strongly suggestive of platelet origin. Those microparticles also displayed the p22 and gp91 subunits of phagocyte-simile NADPH oxidase and exhibited intrinsic reactive oxygen species production. Incubation of endothelial and vascular smooth muscle cells with microparticles enhanced apoptosis rates. Reactive oxygen species generation and apoptosis-inducing activity were markedly greater with exosomes from septic individuals than with exosomes from healthy subjects. These effects were diminished by the addition of superoxide dismutase or the NADPH oxidase inhibitors diphenylene iodonium and phenilarsine oxide.

CONCLUSIONS

Platelet-derived exosome NADPH oxidase activity seems to contribute to vascular cell apoptosis and may represent a new vascular redox-signaling pathway involved in the pathophysiology of sepsis.

S-glutathiolation of Ras mediates redox-sensitive signaling by angiotensin II in vascular smooth muscle cells

Angiotensin II (AII) increases production of reactive oxygen species from NAD(P)H oxidase, a response that contributes to vascular hypertrophy. Here we show in cultured vascular smooth muscle cells that S-glutathiolation of the redox-sensitive Cys(118) on the small GTPase, Ras, plays a critical role in AII-induced hypertrophic signaling. AII simultaneously increased the Ras activity and the S-glutathiolation of Ras (GSS-Ras) detected by biotin-labeled GSH or mass spectrometry. Both the increase in activity and GSS-Ras was labile under reducing conditions, suggesting the essential nature of this thiol modification to Ras activation. Overexpression of catalase, a dominant-negative p47(phox), or glutaredoxin-1 decreased GSS-Ras, Ras activation, p38, and Akt phosphorylation and the induction of protein synthesis by AII. Furthermore, expression of a Cys(118) mutant Ras decreased AII-mediated p38 and Akt phosphorylation as well as protein synthesis. These results show that H(2)O(2) from NAD(P)H oxidase forms GSS-Ras on Cys(118) and increases its activity leading to p38 and Akt phosphorylation, which contributes to the induction of protein synthesis. This study suggests that GSS-Ras is a redox-sensitive signaling switch that participates in the cellular response to AII.

Oxidative stress in the pathogenesis of thoracic aortic aneurysm: protective role of statin and angiotensin II type 1 receptor blocker

OBJECTIVE

The pathogenesis of thoracic aortic aneurysms (TAA) is still unclear. A recent investigation indicated that angiotensin II, a potent activator of NADH/NADPH oxidase, plays an important role in aneurysmal formation. We investigated the potential role of p22phox-based NADH/NADPH oxidase in the pathogenesis of TAA.

METHODS

Human thoracic aneurysmal (n=40) and non-aneurysmal (control, n=39) aortic sections were examined, and the localization of p22phox, an essential component of the oxidase, and its expressional differences were investigated by immunohistochemistry and Western blot. In situ reactive oxygen species (ROS) generation was examined by the dihydroethidium method, and the impact of medical treatment on p22phox expression was investigated by multiple regression analysis.

RESULTS

In situ production of ROS and the expression of p22phox increased markedly in TAA throughout the wall, and Western blot confirmed the enhanced expression of p22phox. The expression was more intense in the regions where monocytes/macrophages accumulated. In these inflammatory regions, numerous chymase-positive mast cells and angiotensin converting enzyme-positive macrophages were present. Their localization closely overlapped the in situ activity of matrix metalloproteinase and the expression of p22phox. Multiple regression analysis revealed that medical treatment with statin and angiotensin II type 1 receptor blocker (ARB) suppressed p22phox expression in TAA.

CONCLUSION

Our findings indicate the role of p22phox-based NADH/NADPH oxidase and the local renin-angiotensin system in the pathogenesis of TAA. Statin and ARB might have inhibitory effects on the formation of aneurysms via the suppression of NADH/NADPH oxidase.

gp91phox-Containing NADPH Oxidase Mediates Endothelial Dysfunction in Renovascular Hypertension

Background— Isoforms of the NADPH oxidase contribute to vascular superoxide anion ( · O 2 − ) formation and limit NO bioavailability. We hypothesized that the endothelial gp91phox-containing NADPH oxidase is predominant in generating the O 2 − to scavenge endothelial NO and thus is responsible for the development of endothelial dysfunction.

Methods and Results— Endothelial dysfunction was studied in aortic rings from wild-type (WT) and gp91phox-knockout (gp91phox −/− ) mice with and without renovascular hypertension induced by renal artery clipping (2K1C). Hypertension induced by 2K1C was more severe in WT than in gp91phox −/− mice (158±2 versus 149±2 mm Hg; P <0.05). Endothelium-dependent relaxation to acetylcholine (ACh) was attenuated in rings from clipped WT but not from clipped gp91phox −/− mice. The reactive oxygen species (ROS) scavenger Tiron, PEG-superoxide dismutase, and the NADPH oxidase inhibitory peptide gp91ds-tat enhanced ACh-induced relaxation in aortae of clipped WT mice. Inhibition of protein kinase C, Rac, and the epidermal growth factor receptor kinase, elements involved in the activation of the NADPH oxidase, restored normal endothelium-dependent relaxation in vessels from clipped WT mice but had no effect on relaxations in those from gp91phox −/− mice. Relaxations to exogenous NO were attenuated in vessels from clipped WT but not clipped gp91phox −/− mice. After removal of the endothelium or treatment with PEG-superoxide dismutase, NO-induced relaxations were identical in vessels from clipped and sham-operated WT and gp91phox mice.

Conclusions— These data indicate that the formation of O 2 − by the endothelial gp91phox-containing NADPH oxidase accounts for the reduced NO bioavailability in the 2K1C model and contributes to the development of renovascular hypertension and endothelial dysfunction.

Salt intake, oxidative stress, and renal expression of NADPH oxidase and superoxide dismutase

The hypothesis that a high salt (HS) intake increases oxidative stress was investigated and was related to renal cortical expression of NAD(P)H oxidase and superoxide dismutase (SOD). 8-Isoprostane PGF(2alpha) and malonyldialdehyde were measured in groups (n = 6 to 8) of conscious rats during low-salt, normal-salt, or HS diets. NADPH- and NADH-stimulated superoxide anion (O(2)(.-)) generation was assessed by chemiluminescence, and expression of NAD(P)H oxidase and SOD were assessed with real-time PCR. Excretion of 8-isoprostane and malonyldialdehyde increased incrementally two- to threefold with salt intake (P < 0.001), whereas prostaglandin E(2) was unchanged. Renal cortical NADH- and NADPH-stimulable O(2)(.-) generation increased (P < 0.05) 30 to 40% with salt intake. Compared with low-salt diet, HS significantly (P < 0.005) increased renal cortical mRNA expression of gp91(phox) and p47(phox) and decreased expression of intracellular CuZn (IC)-SOD and mitochondrial (Mn)-SOD. Despite suppression of the renin-angiotensin system, salt loading enhances oxidative stress. This is accompanied by increased renal cortical NADH and NADPH oxidase activity and increased expression of gp91(phox) and p47(phox) and decreased IC- and Mn-SOD. Thus, salt intake enhances generation of O(2)(.-) accompanied by enhanced renal expression and activity of NAD(P)H oxidase with diminished renal expression of IC- and Mn-SOD.

A 5-week-old HIV-1–exposed girl with failure to thrive and diffuse nodular pulmonary infiltrates

A 5-week-old female infant with vertical HIV-1 exposure, progressive cough, and failure to thrive was given a diagnosis of bilateral diffuse nodular lung lesions. The child was without fever, leukocytosis, anemia, peripheral adenopathy, or hepatosplenomegaly, and the results of repeated blood tests for HIV-1 DNA were negative. A needle biopsy of the lungs revealed granulomatous inflammation and giant cells, with fungal organisms suggestive of Aspergillus species. A nitroblue tetrazolium dye test performed on the patient's blood specimen demonstrated absence of dye reduction, suggesting a diagnosis of chronic granulomatous disease. Further analysis revealed that the child had a deficiency of the p47(phox) component of the nicotinamide adenine dinucleotide phosphate oxidase system. Thus this child with vertical HIV-1 exposure and diffuse pulmonary nodules actually had an autosomal recessive form of chronic granulomatous disease. This case study clearly demonstrates that children with suspected HIV-1 infection might also need evaluation for primary immunodeficiency and that the clinical immunology laboratory is a powerful adjunct in coming to a correct diagnosis.

NAD(P)H Oxidase-derived H2O2 Signals Chloride Channel Activation in Cell Volume Regulation and Cell Proliferation

Cellular swelling triggers the activation of Cl(-) channels (volume-sensitive outwardly rectifying (VSOR) Cl(-) channels) in many cell types. Ensuing regulatory volume decrease has been considered the primary function of these channels. However, Cl(-) channels, which share functional properties with volume-sensitive Cl(-) channels, have been shown to be involved in other physiological processes, including cell proliferation and apoptosis, raising the question of their physiological roles and the signal transduction pathways involved in their activation. Here we report that exogenously applied H(2)O(2) elicited VSOR Cl(-) channel activation. Furthermore, activation of these channels was found to be coupled to NAD(P)H oxidase activity. Also, epidermal growth factor, known to increase H(2)O(2) production, activated Cl(-) channels with properties identical to swelling-sensitive Cl(-) channels. It is concluded that NAD(P)H oxidase-derived H(2)O(2) is the common signal transducing molecule that mediates the activation of these ubiquitously expressed anion channels under a variety of physiological conditions.

Cytoplasmic alkalization precedes reactive oxygen species production during methyl jasmonate- and abscisic acid-induced stomatal closure

Signaling events during abscisic acid (ABA) or methyl jasmonate (MJ)-induced stomatal closure were examined in Arabidopsis wild type, ABA-insensitive (ost1-2), and MJ-insensitive mutants (jar1-1) in order to examine a crosstalk between ABA and MJ signal transduction. Some of the experiments were performed on epidermal strips of Pisum sativum. Stomata of jar1-1 mutant plants are insensitive to MJ but are able to close in response to ABA. However, their sensitivity to ABA is less than that of wild-type plants. Reciprocally, the stomata of ost1-2 are insensitive to ABA but are able to close in response to MJ to a lesser extent compared to wild-type plants. Both MJ and ABA promote H(2)O(2) production in wild-type guard cells, while exogenous application of diphenylene iodonium (DPI) chloride, an inhibitor of NAD(P)H oxidases, results in the suppression of ABA- and MJ-induced stomatal closure. ABA elevates H(2)O(2) production in wild-type and jar1-1 guard cells but not in ost1-2, whereas MJ induces H(2)O(2) production in both wild-type and ost1-2 guard cells, but not in jar1-1. MJ-induced stomatal closing is suppressed in the NAD(P)H oxidase double mutant atrbohD/F and in the outward potassium channel mutant gork1. Furthermore, MJ induces alkalization in guard cell cytosol, and MJ-induced stomatal closing is inhibited by butyrate. Analyses of the kinetics of cytosolic pH changes and reactive oxygen species (ROS) production show that the alkalization of cytoplasm precedes ROS production during the stomatal response to both ABA and MJ. Our results further indicate that JAR1, as OST1, functions upstream of ROS produced by NAD(P)H oxidases and that the cytoplasmic alkalization precedes ROS production during MJ or ABA signal transduction in guard cells.

Effect of aldosterone and glycyrrhetinic acid on the protein expression of PAI-1 and p22(phox) in human mononuclear leukocytes

Aldosterone excess can produce heart and kidney fibrosis, which seem to be related to a direct effect of aldosterone at the level of specific receptors. We report a direct, mineralocorticoid-mediated effect on the protein expression of two markers of oxidative stress after incubation of mononuclear leukocytes with 1 x 10(-8) M aldosterone (p22(phox)/beta-actin = 1.38 +/- 0.05 and PAI-1/beta-actin = 1.80 +/- 0.05). The same effect was also found with 3 x 10(-5) M glycyrrhetinic acid, the principal constituent of licorice root (p22(phox)/beta-actin = 1.37 +/- 0.97 and PAI-1/beta-actin = 1.80 +/- 0.04). The effect of both aldosterone and glycyrrhetinic acid is blocked by incubation with added 1 x 10(-6) M of receptor-antagonist canrenone. Canrenone alone did not show any effect. PAI-1 related protein was also found using 4 x 10(-9) M aldosterone. Incubations with 1 x 10(-9) M for 3 hours as well as 1 x 10(-8) M aldosterone for 5, 10, and 20 minutes were ineffective for both proteins. These data support the previous finding of an involvement of mononuclear leukocytes in the pathogenesis of the oxidative stress induced by hyperaldosteronism. In addition, the results confirm our previous data on a direct effect of glycyrrhetinic acid at the level of mineralocorticoid receptors.

p22phox-derived superoxide mediates enhanced proliferative capacity of diabetic vascular smooth muscle cells

To investigate the mechanisms that contribute to the acceleration of atherosclerosis in diabetes, the role of NAD(P)H oxidase in the enhanced proliferative capacity of diabetic vascular smooth muscle cells (VSMC) was studied. VSMC from streptozotocin (STZ)-induced diabetic rat aorta had increased proliferative capacity and generated higher levels of superoxide in comparison with cells from control rats. Both the enhanced proliferation and superoxide generation in diabetic VSMC were significantly attenuated not only by tiron (1mM), a superoxide scavenger but also by diphenyleneiodonium (DPI; 10microM), an NAD(P)H oxidase inhibitor. Both the activity of NAD(P)H oxidase and p22phox expression were significantly increased in diabetic VSMC. Furthermore, inhibition of p22phox expression by transfection of antisense p22phox oligonucleotides into diabetic VSMC resulted in a decrease in superoxide generation, which was accompanied by a significant attenuation of cell proliferation. Based on these results, it is suggested that diabetes-associated increase in NAD(P)H oxidase activity via enhanced expression of p22phox contributes to augmented VSMC proliferation in diabetic rats.

Thermal treatment attenuates neointimal thickening with enhanced expression of heat-shock protein 72 and suppression of oxidative stress

BACKGROUND

The beneficial effects of thermal therapy have been reported in several cardiovascular diseases. However, it is unknown whether the thermal treatment has some beneficial roles against the development of atherosclerosis.

METHODS AND RESULTS

The inflammatory arterial lesion was introduced by placement of a polyethylene cuff on femoral arteries of male Sprague-Dawley rats for 4 weeks. Thermal-treated group underwent daily bathing in 41 degrees C hot water for 15 minutes. Neointimal thickening along with immunohistochemical expression of heat-shock proteins (HSPs), monocyte chemoattractant protein-1 (MCP-1), and NADPH oxidase were compared with those of a thermally untreated (Control) group. Morphometric analysis demonstrated a significant suppression of neointimal thickening in thermal-treated group compared with the Control group (intimal/medial area ratios, 0.01+/-0.01 versus 0.31+/-0.04, P<0.01). Expression of MCP-1 and infiltration of ED-positive cells were enhanced in the adventitial layer of Control. More importantly, expression of HSP72 in media was enhanced by thermal treatment. Expression of p22-phox, the major membrane subunit of NADPH oxidase, and MCP-1 was augmented in cuff-injured adventitia of the Control but not the thermal-treated groups.

CONCLUSIONS

Thermal treatment significantly attenuated infiltration of inflammatory cells in adventitia and suppressed neointimal thickening in cuff-injured arteries with the enhancement of HSP72 expression and suppression of oxidative stress.

Fc epsilon RI signaling of mast cells activates intracellular production of hydrogen peroxide: role in the regulation of calcium signals

Earlier studies, including our own, revealed that activation of mast cells is accompanied by production of reactive oxygen species (ROS) that help to mediate the release of the inflammatory mediators, including histamine and eicosanoids. However, little is known about the mechanisms of ROS production, including the species of oxidants produced. In this study we show that in both the RBL-2H3 mast cell line and bone marrow-derived mast cells, FcepsilonRI cross-linking stimulates intracellular oxidative burst, including hydrogen peroxide (H(2)O(2)) production, as defined with the oxidant-sensitive dyes dichlorofluorescein and scopoletin and the selective scavenger ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one). The oxidative burst was observed immediately after stimulation and was most likely due to an NAD(P)H oxidase. Experiments using selective pharmacological inhibitors demonstrated that activation of tyrosine kinases and phosphatidylinositol-3-kinase is required for induction of the oxidative burst. Blockade of the oxidative burst by diphenyleneiodonium impaired the release of preformed granular mediators, such as histamine and beta-hexosaminidase, and the secretion of newly synthesized leukotriene C(4), whereas selective scavenging H(2)O(2) by ebselen impaired leukotriene C(4) secretion, but not degranulation. Sustained elevation of cytosolic calcium through store-operated calcium entry was totally abolished when ROS production was blocked. In contrast, selective depletion of H(2)O(2) caused a considerable decrease and delay of the calcium response. Finally, tyrosine phosphorylation of phospholipase Cgamma and the linker for activation of T cells, an event required for calcium influx, was suppressed by diphenyleneiodonium and ebselen. These studies demonstrate that activation of the intracellular oxidative burst is an important regulatory mechanism of mast cell responses.

ROS-related enzyme expressions in endothelial cells regulated by tea polyphenols

OBJECTIVE

Elevation of reactive oxygen species (ROS), especially the level of superoxide is a key event in many forms of cardiovascular diseases. To study the mechanism of tea polyphenols against cardiovascular diseases, we observed the expressions of ROS-related enzymes in endothelial cells.

METHODS

Tea polyphenols were co-incubated with bovine carotid artery endothelial cells (BCAECs) in vitro and intracellular NADPH oxidase subunits p22phox and p67phox, SOD-1, and catalase protein were detected using Western blot method.

RESULTS

Tea polyphenols of 0.4 microg/mL and 4.0 microg/mL (from either green tea or black tea) down-regulated NADPH oxidase p22phox and p67phox expressions in a dose-negative manner (P < 0.05), and up-regulated the expressions of catalase (P < 0.05).

CONCLUSIONS

Tea polyphenols regulate the enzymes involved in ROS production and elimination in endothelial cells, and may be beneficial to the prevention of endothelial cell dysfunction and the development of cardiovascular diseases.

Anti-Inflammatory and Profibrinolytic Effect of Insulin in Acute ST-Segment–Elevation Myocardial Infarction

Background— The clinical benefits of insulin previously observed in acute ST-segment–elevation myocardial infarction (STEMI) may be partially explained by an anti-inflammatory effect. We assessed this potential effect of insulin in STEMI patients treated with fibrinolytics.

Methods and Results— Thirty-two patients receiving reteplase were randomly assigned infusions of either insulin at 2.5 U/h, dextrose, and potassium (GIK) or normal saline and potassium (C) for 48 hours. Plasma concentrations of high-sensitivity C-reactive protein (CRP), serum amyloid A (SAA), plasminogen activator inhibitor-1 (PAI-1), creatine kinase (CK), and CK-MB were measured at baseline and sequentially for 48 hours. Total p47 phox protein in mononuclear cells was measured in a subgroup of 13 subjects. Baseline CRP and SAA were significantly increased (2- to 4-fold) at 24 and 48 hours in each group ( P <0.01). However, in the insulin group, there was a significant ( P <0.05) attenuation of the absolute rise in concentration of CRP and SAA from baseline. The absolute increase of CRP and SAA was reduced by 40% (CRP) and 50% (SAA) at 24 hours and at 48 hours compared with the control group. The absolute increase in PAI-1 from baseline and the percentage increase in p47 phox over 48 hours were significantly ( P <0.05) lower in the insulin-treated group. CK-MB peaked earlier and tended to be lower in insulin-treated subjects, especially in patients with inferior MI.

Conclusions— Insulin has an anti-inflammatory and profibrinolytic effect in patients with acute MI. These effects may contribute to the clinical benefits of insulin in STEMI.

SATB1 makes a complex with p300 and represses gp91(phox) promoter activity

The expression of gp91(phox), the key component of the phagocyte NADPH oxidase, is regulated by various factors binding to its proximal promoter. Two nuclear matrix attachment region (MAR)-binding proteins, special AT-rich binding protein 1 (SATB1) and CCAAT displacement protein (CDP), have been reported as rare examples of gp91(phox) gene repressors. However, their individual roles and interactions with other factors in the promoter have not been elucidated in detail. We have focused on these two repressive proteins recognizing the bp -115 to bp -106 segment of the gene and obtained the following results: 1. SATB1 makes a complex, mainly with p300, regardless of the presence of DNA. 2. SATB1/p300 complex binding to the 5' upstream AT-rich region in the bp -115 to bp -106 segment represses the gp91(phox) promoter activity, and the repressed activity is partially released by CDP binding to the CCAAT element directly downstream of the AT-rich region. Our findings imply a novel role for p300 in SATB1-associated global transcription regulation.

NAD(P)H oxidase inhibitor prevents blood pressure elevation and cardiovascular hypertrophy in aldosterone-infused rats

Increased bioavailability of reactive oxygen species (ROS) has been implicated in the pathogenesis of mineralocorticoid hypertension. To find out the source of ROS, we evaluated the role of NAD(P)H oxidase in blood pressure (BP) elevation, cardiovascular hypertrophy, and fibrosis in aldosterone-salt rats. Aldosterone infusion (0.75 microg/h) significantly increased BP, which is attenuated by apocynin (1.5 mmol/L). Cardiac hypertrophy developed by aldosterone infusion was also normalized with apocynin. Greater mRNA for p22phox and NAD(P)H oxidase activity (more than twofold) in aorta of aldosterone-infused rats was reduced in apocynin-treated rats. Aldosterone infusion increased marginally procollagen I and III expression in LV compared to controls and apocynin decreased procollagen. Masson's Trichrome stain showed increased cardiac perivascular fibrosis, which was reduced by apocynin. These results suggest that NAD(P)H oxidase plays an important role in cardiovascular damage associated with mineralocorticoid hypertension.

[A case of Williams syndrome with p47-phox-deficient chronic granulomatous disease]

A 2-month-old boy with a characteristic elfin face was diagnosed as having Williams syndrome by means of specific fluorescence in situ hybridization (FISH) analysis for a chromosomal microdeletion located in 7q11.23. He was suspected to have immunodeficiency because of a persistent enlargement of axillary lymphnodes after immunization with Bacille Calmette-Guerin (BCG) vaccine since 7 month-old of age. The nitroblue tetrazolium test (NBT) and the chemiluminescence test revealed an absence of superoxide production. Western blotting and DNA sequence analysis confirmed the diagnosis of p47-phox-deficient autosomal recessive chronic granulomatous disease (CGD) (A47 degrees CGD). The predominant genetic defect in A47 degrees CGD was a GT deletion at the beginning of exon 2 in neutrophil cytosol factor 1 gene (NCF1) located in 7q11.23. It suggests that CGD in this patient resulted from the hemizygosity of recessive genetic mutation in NCF1 located at 7q11.23 associated with Williams syndrome. In such a disease with the chromosomal microdeletion like Williams syndrome, we should consider a combination with autosomal recessive diseases, the genes of which are located in the hemizygous region.

Nitric oxide synthase and NAD(P)H oxidase modulate coronary endothelial cell growth

Reactive oxygen species (ROS) including nitric oxide (NO) and superoxide anion (O(2)(-)) are associated with cell migration, proliferation and many growth-related diseases. The objective of this study was to determine whether there was a reciprocal relationship between rat coronary microvascular endothelial cell (CMEC) growth and activity/expressions (mRNA and protein) of endothelial NO synthase (eNOS) and NAD(P)H oxidase enzymes. Proliferating namely, 50% confluent CMEC possessed approximately threefold increased activity and expression of both enzymes compared to 100% confluent cells. Treatment of CMEC with an inhibitor of eNOS (L-NAME, 100 microM) increased cell proliferation as assessed via three independent methods, i.e. cell counting, determination of total cellular protein levels and [(3)H]-thymidine incorporation. Similarly, treatment of CMEC with pyrogallol (0.3-3 mM), a superoxide anion (O(2)(-)) generator, also increased CMEC growth while spermine NONOate (SpNO), a NO donor, significantly reduced cell growth. Co-incubation of CMEC with a cell permeable superoxide dismutase mimetic (Mn-III-tetrakis-4-benzoic acid-porphyrin; MnTBAP) plus either pyrogallol or NO did not alter cell number and DNA synthesis thereby dismissing the involvement of peroxynitrite (OONO(-)) in CMEC proliferation. Specific inhibitors of NAD(P)H oxidase but not other ROS-generating enzymes including cyclooxygenase and xanthine oxidase, attenuated cell growth. Transfection of CMEC with antisense p22-phox cDNA, a membrane-bound component of NAD(P)H oxidase, resulted in substantial reduction in [(3)H]-thymidine incorporation, total cellular protein levels and expression of p22-phox protein. These data demonstrate a cross-talk between CMEC growth and eNOS and NAD(P)H oxidase enzyme activity and expression, thus suggesting that the regulation of these enzymes may be critical in preventing the initiation and/or progression of coronary atherosclerosis.

Relation between development of nephropathy and the p22phox C242T and receptor for advanced glycation end product G1704T gene polymorphisms in type 2 diabetic patients

OBJECTIVE

The development of diabetic nephropathy is considered to be associated with oxidative stress. NADPH oxidase and the receptor for advanced glycation end products (RAGE) have attracted attention as mechanisms of generating oxidative stress. We studied the relation between the genotypes of the NADPH p22phox C242T and RAGE G1704T polymorphisms and the development of diabetic nephropathy in type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

Using a retrospective review of clinical data, we allocated 181 Japanese type 2 diabetic patients to one of two groups: patients without diabetic nephropathy (group N; n = 108) and patients developing diabetic nephropathy (group D; n = 73) for 10 years or more. The p22phox C242T and RAGE G1704T polymorphisms were examined by Taqman PCR methods.

RESULTS

The frequency of the p22phox CC genotype was significantly higher in group D than in group N (90 vs. 79%; P = 0.0427). The frequency of the RAGE GT + TT genotype was significantly higher in group D than in group N (26 vs. 13%; P = 0.0313). The frequency of the combination of p22phox CC and RAGE GT + TT genotypes was significantly higher in group D than in group N (22 vs. 8%; P = 0.0057). In multiple logistic regression analysis, systolic blood pressure, HbA(1c), triglycerides, and the combination of polymorphisms were shown to be independent variables.

CONCLUSIONS

These results suggest that assessment of the combination of NADPH p22phox C242T and RAGE G1704T polymorphisms may be useful in identifying the risk for developing diabetic nephropathy in type 2 diabetic patients.

Lack of evidence for association of high altitude pulmonary edema and polymorphisms of the NO pathway

One essential factor in the development of high altitude pulmonary edema (HAPE) is elevated pulmonary artery pressure, possibly due to a lack of nitric oxide (NO) in pulmonary vessels. NOS3 gene polymorphisms (G894T, T-786C, and CA-repeats > or =38) might be linked to decreased NO synthesis and increased susceptibility to HAPE, while the C242T polymorphism of the CYBA gene [encoding for the NAD(P)H oxidase subunit p22phox] may increase NO availability and thus convey resistance to HAPE. To test this hypothesis, we genotyped 51 mountaineers susceptible and 52 mountaineers not susceptible to HAPE. Genotyping revealed similar genotype frequencies of the G894T and the T-786C NOS3 polymorphism in both groups (G894T: susceptibles, 39.2% GG, 47.1% GT, 13.7% TT; nonsusceptibles, 48.0% GG, 44.0% GT, 8.0% TT; p = 0.54. T-786C: susceptibles, 45.1% TT, 39.2% TC, 15.7% CC; nonsusceptibles, 53.8% TT, 40.4% TC, 5.8% CC; p = 0.28). Genotype frequencies of the C242T CYBA polymorphism were 43.1% CC, 47.1 % CT, and 9.8% TT in HAPE susceptibles and 38.0% CC, 52.0 % CT, and 10.0% TT (p = 0.92) in nonsusceptibles. There was also no difference between the two groups in the number of CA repeats (p = 0.57), and individuals with > or =38 CA repeats were not more likely to develop HAPE (p = 1.0). Haplotype analysis for the NOS3 polymorphisms also revealed no association with HAPE. The results of this study suggest that none of these genetic variants plays a substantial role in the pathogenesis of HAPE in Caucasians, but does not exclude epistatic effects that might still involve the genetic systems studied here.

Inhibition of formyl-methionyl-leucyl-phenylalanine-stimulated respiratory burst in human neutrophils by adrenaline: inhibition of Phospholipase A2 activity but not p47phox phosphorylation and translocation

The polymorphonuclear neutrophil (PMN)-respiratory burst plays a key role in host defense and inflammatory reactions. Modulation of this key neutrophil function by endogenous agents and the mechanisms involved are poorly understood. This study was designed to analyze the mechanisms involved in the effect of adrenaline on neutrophil superoxide anions production. Using the superoxide dismutase (SOD)-inhibitable cytochrome c reduction assay, we report here that the beta-adrenergic agonist, adrenaline at physiologic concentrations (5-100 nM) inhibited formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated but not phorbol-myristate-acetate (PMA)-stimulated PMN superoxide anion production. The inhibitory effect of adrenaline runs in parallel with an increase in intracellular levels of cAMP which was reversed by the protein kinase A (PKA) inhibitor H-89, suggesting a role for PKA in mediating the inhibitory effect of adrenaline on fMLP-induced superoxide production. Adrenaline at physiological concentrations did not inhibit the fMLP-stimulated membrane translocation of the NADPH oxidase components p47phox and p67phox, nor the fMLP-stimulated phosphorylation of p47phox. However, adrenaline strongly depressed the activity of the cytosolic isoform of Phospholipase A(2) (cPLA(2)). We suggest that adrenaline inhibits fMLP induced superoxide production upstream of the NADPH oxidase via a mechanism involving PKA and cPLA(2).

Vascular oxidant stress enhances progression and angiogenesis of experimental atheroma

BACKGROUND

Although multiple pathological processes have been associated with oxidative stress, the causative relation between oxidative stress and arterial lesion progression remains unclear.

METHODS AND RESULTS

To test the effect of creating arterial wall oxidative stress, we compared progression of mouse carotid lesions induced by flow cessation in the wild-type (WT) versus transgenic mice (Tg(p22vsmc)), in which overexpression of p22phox, a critical component of NAD(P)H oxidase was targeted to smooth muscle cell (SMC). Compared with WT mice, arterial lesions grew significantly larger in Tg(p22vsmc) (P<0.001) and demonstrated elevated hydrogen peroxide (H2O2) and vascular endothelial growth factor (VEGF) levels at all time points examined (P<0.001, n=4 animals per time point), probably related to increased expression of hypoxia inducible factor (HIF)-1alpha via SMC oxidative stress in the Tg(p22vsmc) arteries, both basally (203+/-12% versus WT, P<0.001, n=3) and after lesion formation. Interestingly, Tg(p22vsmc) lesions were complicated by extensive neointimal angiogenesis. In vitro experiments confirmed SMCs isolated from Tg(p22vsmc) to be the source for increased H2O2, VEGF, and HIF-1alpha and their capacity to induce angiogenic cord-like structures when cocultured with endothelial cells. The antioxidant ebselen inhibited SMC activities in vitro and intralesion angiogenesis and lesion progression in vivo.

CONCLUSIONS

We have demonstrated a novel pathway by which oxidative stress can trigger in vivo an angiogenic switch associated with experimental plaque progression and angiogenesis. This pathway may be related to human atheroma progression and destabilization through intraplaque hemorrhage.

Nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) P22 Phox C242T gene polymorphism in type 1 diabetes

Type 1 diabetes is caused by the immune-mediated destruction of insulin-secreting pancreatic beta cells and is thought to be an autoimmune disease resulting from a complex interaction of genetic and environmental factors. In animal models of type 1 diabetes, macrophages and their products, superoxides, have central roles in the beta cell destruction, but in humans their roles remain unclear. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase produces superoxide in macrophages, and its essential component, p22 phox, is a critical enzyme for superoxide production. The C242T polymorphism in the p22 phox coding gene has been reported to be associated with reduced oxidase activity. We therefore investigated whether the p22 phox gene polymorphism affected the susceptibility to and clinical course of type 1 diabetes. We examined 287 Japanese type 1 diabetic patients and 425 unrelated nondiabetic subjects. In addition, we allocated the diabetic patients to the following three groups: (1) acute-onset type 1 diabetes with at least one autoantibody (GADA, IA-2, IAA); (2) acute-onset type 1 diabetes without autoantibodies; and (3) slow-onset type 1 diabetes with autoantibody. We could not find a significant difference in p22 phox genotype and T allele frequency between overall type 1 diabetic patients and control subjects. Regardless of the onset pattern and autoantibody positivity of type 1 diabetes, no difference in p22 phox genotype and T allele frequency was found among the groups. In conclusion, the p22 phox C242T gene polymorphism did not affect the susceptibility to and clinical course of Japanese type 1 diabetes.

Gender differences in superoxide generation in microvessels of hypertensive rats: role of NAD(P)H-oxidase

OBJECTIVE

This study is aimed to explore whether gender plays a role in the generation of nitric oxide (NO) and superoxide anion (O(2)(-)) in microvessels of hypertensive rats (SHR), as well as the potential mechanisms involved in these effects.

METHODS AND RESULTS

NO generation in mesenteric arterioles was evaluated by measuring NO synthase (NOS) activity and protein expression. Oxidative stress was studied in vivo in mesenteric arterioles from male and female SHR by hydroethidine microfluorography. Although we did not observe any sex-related differences in NO generation, we found that hydroethitine oxidation is markedly increased (30.9+/-2.4%) in male compared to female (12.3+/-2.5%; p<0.05), demonstrating a gender difference in O(2)(-) production. The treatment of mesenteries with DPI (NAD(P)H-oxidase inhibitor) and treatment of SHR with losartan [Angiotensin-II type 1 (AT-1) receptor antagonist] markedly reduced O(2)(-) production in male, while produced a minor effect in female, suggesting that overexpression/activity of AT-1 receptor and NAD(P)H-oxidase contribute for the sexual dimorphism in superoxide generation. Immunoblot analyses provide evidences of overexpression of the NAD(P)H-oxidase components p22(phox), gp91(phox), p47(phox) and p67(phox) in arterioles from male in comparison to female. Losartan treatment inhibited the overexpression of these subunits in male, without affecting the responses in female.

CONCLUSION

Taken together, our findings demonstrate that male SHR presents higher superoxide anion concentration under basal condition than does female. An AT-1-dependent overexpression of the NAD(P)H-oxidase components may account for the sexual dimorphism in oxidative stress, and may play an important role in the noted gender differences on incidence of cardiovascular disease.

Role of p22phox in angiotensin�II and platelet-derived growth factor AA induced activator protein 1 activation in vascular smooth muscle cells

Reactive oxygen species (ROS) are involved in the transcriptional response to angiotensin (ANG) II. In this setting the role of NAD(P)H oxidase, an important source of ROS as second messengers, is not completely understood. In particular in human cells detailed insights into this mechanism are lacking. We investigated the role of ANG II and platelet-derived growth factor (PDGF) AA induced ROS generation derived from p22phox-containing NAD(P)H oxidase in the activation of activator protein (AP) 1 in human vascular smooth muscle cells (SMCs). Both ANG II and PDGF AA induced ROS generation in SMCs which was angiotensin type 1 receptor and PDGF alpha receptor dependent. Specific inhibition of the p22phox subunit of the NAD(P)H oxidase using either p22phox neutralizing antibody or p22phox antisense oligodeoxynucleotides (ODNs) attenuated both ANG II and PDGF AA induced ROS generation. Furthermore, PDGF AA but not ANG II induced p22phox mRNA expression. ANG II and PDGF AA both activated the redox-sensitive transcription factor AP-1, which was inhibited by p22phox antisense ODNs. These findings demonstrate that AP-1 activation in human SMCs in response to ANG II and PDGF AA is mediated via generation of p22phox-dependent ROS. This highlights the crucial role of the p22phox-containing NAD(P)H oxidase in the ANG II and PDGF AA induced signal transduction pathway.

A possible involvement of plasma membrane NAD(P)H oxidase in the switch mechanism of the cell death mode from apoptosis to necrosis in menadione-induced cell injury

The effects of inhibitors of plasma membrane NADPH oxidase on menadione-induced cell injury processes were studied using human osteosarcoma 143B cells. The intracellular level of superoxide in the cells treated with menadione for 6 h reached a maximum followed by an abrupt decrease. The population of apoptotic cells detected by Annexin V and propidium iodide double staining also reached its maximum at 6 h of menadione-treatment while that of necrotic cells increased continuously reaching 90% of the total population at 9 h of the treatment. Pretreatment of the cells with inhibitors of NADPH oxidase, including diphenyliodonium chloride, apocynin, N-vanillylnonanamide and staurosporine was effective in lowering the menadione-induced elevations of superoxide, and also in the suppression of the switch of the cell death mode from apoptosis to necrosis in menadione-treated cells except for the case of staurosporine. These results strongly suggest that superoxide generated by NADPH oxidase, besides that generated by the mitochondria, may contribute to the remarkable increase in the intracellular level of superoxide in the cells treated with menadione for 6 h resulting in the switch from apoptosis to necrosis, although a direct evidence of the presence of active and inactive forms of NADPH oxidase in control and menadione-treated 143B cells is lacking at present.

Association of gene polymorphisms with coronary artery disease in individuals with or without nonfamilial hypercholesterolemia

A substantial proportion of individuals with coronary artery disease (CAD) has concomitant hypercholesterolemia. A large-scale association study was performed to identify separately genes that confer susceptibility to CAD in the absence or presence of nonfamilial hypercholesterolemia. The study population comprised 5248 unrelated Japanese individuals, including 3085 subjects with CAD (2350 men, 735 women) and 2163 controls (1329 men, 834 women). Among all study subjects, 2541 individuals (1688 men, 853 women) had nonfamilial hypercholesterolemia, and 2707 individuals (1991 men, 716 women) did not have this condition. The genotypes for 33 polymorphisms of 27 candidate genes were determined with a fluorescence- or colorimetry-based allele-specific DNA primer-probe assay system. Multivariate logistic regression analysis with adjustment for age, body mass index, and the prevalence of smoking, hypertension, diabetes mellitus, and hyperuricemia revealed that three polymorphisms [994G --> T (Val279Phe) in the platelet-activating factor acetylhydrolase gene, 242C --> T (His72Tyr) in the NADH/NADPH oxidase p22 phox gene, and 1100C --> T in the apolipoprotein C-III gene] were significantly associated with CAD in men with hypercholesterolemia. Genotyping of these three polymorphisms may prove informative for prediction of the genetic risk for CAD in men with nonfamilial hypercholesterolemia.