Search

Background Sepsis-induced acute lung injury (ALI) accounts for about 40% of ALI, accompanied by alveolar epithelial injury. The study aimed to reveal the role of circular RNA_0114428 (circ_0114428) in sepsis-induced ALI. Methods Human pulmonary alveolar epithelial cells (HPAEpiCs) were treated with lipopolysaccharide (LPS) to mimic a sepsis-induced ALI cell model. RNA expression of circ_0114428, miR-574-5p and Rho-associated coiled-coil containing protein kinase 2 (ROCK2) was detected by qRT-PCR. Protein expression was checked by Western blotting. Cell viability, proliferation and apoptosis were investigated by cell counting kit-8, 5-Ethynyl-29-deoxyuridine (EdU) and flow cytometry analysis, respectively. The levels of pro-inflammatory factors were detected by enzyme-linked immunosorbent assay (ELISA). Oxidative stress was analyzed by lipid peroxidation Malondialdehyde (MDA) and Superoxide Dismutase (SOD) activity detection assays. The interplay among circ_0114428, miR-574-5p and ROCK2 was identified by dual-luciferase reporter, RNA pull-down and RNA immunoprecipitation assays. Results Circ_0114428 and ROCK2 expression were significantly increased, but miR-574-5p was decreased in blood samples from sepsis patients and LPS-stimulated HPAEpiCs. LPS treatment led to decreased cell viability and proliferation and increased cell apoptosis, inflammation and oxidative stress; however, these effects were relieved after circ_0114428 knockdown. Besides, circ_0114428 acted as a miR-574-5p sponge and regulated LPS-treated HPAEpiC disorders through miR-574-5p. Meanwhile, ROCK2 was identified as a miR-574-5p target, and its silencing protected against LPS-induced cell injury. Importantly, circ_0114428 knockdown inhibited ROCK2 production by interacting with miR-574-5p. Conclusion Circ_0114428 knockdown protected against LPS-induced HPAEpiC injury through miR-574-5p/ROCK2 axis, providing a novel therapeutic target in sepsis-induced ALI. Keywords: ALI, circ_0114428, miR-574-5p, ROCK2, LPS, Author(s): Jing Zhao[sup.1], Qin Zhao[sup.2] and Qiuxia Duan[sup.3] Introduction Developing as a result of immune response to pathogen-induced infection, sepsis is a complicated disorder with a high mortality rate of [...]

We tested the hypothesis that ethanol consumption would aggravate the renal damage induced by cyclophosphamide (CYP). Male C57BL/6 J mice from control (n = 8) and CYP (n = 12) groups had free access to filtered water and standard rodent chow for 12 weeks. Then, 24 h before euthanasia mice received an intraperitoneal injection of saline or CYP (300 mg/kg). Mice from ethanol (n = 8) and CYP + ethanol (n = 12) groups had free access to increasing doses of ethanol for 12 weeks. Twentyfour hours before euthanasia, mice from ethanol and CYP + ethanol groups received an intraperitoneal injection of saline or CYP, respectively. Ethanol, CYP, or the association of both drugs augmented serum levels of creatinine and increased the levels of superoxide ([O.sup.*-.sub.2]) generation and thiobarbituric acid reactive substances in the renal cortex. Upregulation of Nox4 and increased activity of superoxide dismutase were detected in the renal cortex of mice treated with ethanol, CYP, or the combination of these drugs; however, these molecular alterations induced by CYP were not potentiated by ethanol consumption. Our findings revealed that chronic ethanol consumption had no potentiating effect on the nephrotoxic effects displayed by CYP. It is possible that the combination of these drugs showed no synergistic effect because they share the same molecular mechanisms of renal toxicity. Key words: ethanol, cyclophosphamide, kidney, reactive oxygen species, oxidative stress. Nous avons confronte l'hypothese selon laquelle la consommation d'ethanol aggraverait les dommages renaux engendres par la cyclophosphamide (CYP). Nous avons donne a des souris C57BL/6J males de groupes temoin (n = 8) et CYP (n = 12) acces a de l'eau filtree et de la moulee pour rongeur standard pendant 12 semaines. Puis, 24 h avant l'euthanasie des souris, nous avons procede a l'injection intraperitoneale d'une solution saline ou de CYP (300 mg/kg). Nous avons donne aux souris des groupes ethanol (n = 8) et CYP + ethanol (n = 12) acces a des doses croissantes d'ethanol sur 12 semaines. Vingtquatre heures avant l'euthanasie, nous avons procede a l'injection de solution saline ou de CYP dans les groupes ethanol et CYP + ethanol, respectivement. L'ethanol, la CYP ou l'association des deux entrainait une augmentation des taux de creatinine avec une augmentation de la production d'ions superoxydes ([O.sup.*-.sub.2]) et de derives reactifs de l'acide thiobarbiturique (TBARS) dans le cortex renal. Nous avons observe une regulation a la hausse de Nox4 et une augmentation de l'activite de la syperoxyde dismutase (SOD) dans le cortex renal des souris auxquelles etait administre de l'ethanol, de la CYP ou l'association des deux. Cependant, ces alterations moleculaires engendrees par la CYP n'etaient pas potentialisees par la consommation d'ethanol. Nos resultats ont revele que la consommation d'ethanol a long terme n'avait pas d'effet potentialisateur sur les effets nephrotoxiques affiches par la CYP. Il est possible que l'association de ces produits ne montrait aucun effet synergique parce que leur toxicite renale passe par les memes modes d'action moleculaires. [Traduit par la Redaction] Mots-cles: ethanol, cyclophosphamide, rein, derives reactifs de l'oxygene, stress oxydatif., Introduction Cyclophosphamide (CYP) is a chemotherapeutic agent widely used against cancer. CYP is an alkylating agent that exerts its pharmacological activity by binding to DNA and preventing its replication (Matz [...]

Resveratrol (RV), a polyphenolic component of red wine, has been shown to attenuate high blood pressure (BP) in spontaneously hypertensive rats (SHRs). We previously found that the enhanced expression of Gi[alpha] proteins plays a role in the pathogenesis of hypertension in SHRs. In the present study, we investigated whether this RV-induced decrease in BP in SHRs can be attributed to the ability of RV to inhibit the enhanced expression of Gi[alpha] proteins and the upstream signaling molecules implicated in the overexpression of Gi[alpha] proteins. Administration of RV (50 mg/kg per day) to prehypertensive 2-week-old SHRs for 6 weeks prevented the development of high BP and inhibited the enhanced expression of Gi[alpha] proteins, the enhanced levels of superoxide anion ([O.sub.2.sup.-]) and NADPH oxidase activity, the enhanced activation (phosphorylation) of c-Src and growth factor receptors, as well as the enhanced levels of extracellular signal-regulated kinase 1/2 (ERK1/2) and protein kinase B (Akt) exhibited by vascular smooth muscle cells isolated from SHRs. In conclusion, these results indicate that RV attenuates the development of high BP in SHRs through the inhibition of enhanced levels of Gi[alpha] proteins, oxidative stress, and the upstream signaling molecules that contribute to the overexpression of Gi[alpha] proteins. These findings suggest that RV could potentially be used as a therapeutic agent in the treatment of cardiovascular complications including hypertension. Key words: resveratrol, Gi[alpha] proteins, blood pressure, VSMC, SHR. Le resveratrol (RV), une composante polyphenolique du vin rouge, est decrit comme pouvant permettre d'attenuer l'augmentation de la tension arterielle (TA) chez le rat spontanement hypertendu (SHR). Nous avons precedemment observe que l'augmentation de l'expression des proteines Gi[alpha] joue un role dans la pathogenese de l'hypertension chez le rat SHR. Dans la presente etude, nous avons evalue si cette diminution de la TA engendree par le RV chez le rat SHR peut etre attribuee a la capacite du RV d'inhiber l'augmentation de l'expression des proteines Gi[alpha] et des molecules des voies de signalisation jouant un role en amont dans la surexpression des proteines Gi[alpha]. L'administration sur 6 semaines de RV(50 mg/kg par jour) prealablement a l'hypertension chez des rats SHR de 2 semaines permettait de prevenir l'apparition d'une TA elevee, ainsi d'inhiber l'augmentation de l'expression des proteines Gi[alpha], des taux d'anions superoxydes ([O.sub.2.sup.-]), de l'activite oxydative de la NADPH, de l'activation (phosphorylation) de la c-Src, avec une augmentation des taux des recepteurs de facteurs de croissance, d'ERK1/2 (pour << extracellular signal-regulated kinase 1/2 >>) et de la proteine kinase B (Akt) exprimes par des cellules musculaires lisses vasculaires isolees de rats SHR. En conclusion, ces resultats montrent que le RV permet d'attenuer l'augmentation de la TA chez le rat SHR par l'intermediaire d'une inhibition de l'augmentation des taux de proteines Gi[alpha], du stress oxydatif, ainsi que la hausse des molecules des voies de signalisation contribuant en amont a la surexpression des proteines Gi[alpha]. Ces resultats laissent entendre que le RV pourrait eventuellement etre utilise comme agent therapeutique dans le traitement de complications cardiovasculaires, y compris l'hypertension. [Traduit par la Redaction] Mots-cles: resveratrol, proteines Gi[alpha], tension arterielle, cellules musculaires lisses vasculaires, rat SHR., Introduction Heterotrimeric guanine nucleotide regulatory proteins (G proteins) regulate a variety of physiological functions--such as vascular tone and reactivity, cardiac contractility, and cell proliferation--through the activation of a variety of [...]

Extracellular superoxide dismutase (ECSOD or SOD3) is highly expressed in lungs and functions as a scavenger of [O.sub.2.sup.*-]. ECM fragmentation, which can be triggered by oxidative stress, participates in the pathogenesis of chronic obstructive pulmonary disease (COPD) through attracting inflammatory cells into the lungs. The level of SOD3 is significantly decreased in lungs of patients with COPD. However, the role of endogenous SOD3 in the development/progression of emphysema is unknown. We hypothesized that SOD3 protects against emphysema by attenuating oxidative fragmentation of ECM in mice. To test this hypothesis, SOD3-deficient, SOD3-transgenic, and WT C57BL/6J mice were exposed to cigarette smoke (CS) for 3 d (300 mg total particulate matter/[m.sup.3]) to 6 mo (100 mg/[m.sup.3] total particulate matter) or by intratracheal elastase injection. Airspace enlargement, lung inflammation, lung mechanical properties, and exercise tolerance were determined at different time points during CS exposure or after elastase administration. CS exposure and elastase administration caused airspace enlargement as well as impaired lung function and exercise capacity in SOD3-null mice, which were improved in mice overexpressing SOD3 and by pharmacological SOD mimetic. These phenomena were associated with SOD3-mediated protection against oxidative fragmentation of ECM, such as heparin sulfate and elastin, thereby attenuating lung inflammatory response. In conclusion, SOD3 attenuates emphysema and reduces oxidative fragmentation of ECM in mouse lung. Thus, pharmacological augmentation of SOD3 in the lung may have a therapeutic potential in the intervention of COPD/emphysema. antioxidants | cigarette smoke | chronic obstructive pulmonary disease | oxidants | glutathione doi/ 10.1073/pnas.1007625107

Oxidative stress plays an important role in the pathogenesis of anti-glomerular basement membrane antibody-induced glomerulonephritis (anti-GBMGN). Superoxide dismutase (SOD) is the first line of defense against oxidative stress by converting superoxide to hydrogen peroxide ([H.sub.2][O.sub.2]). We investigated the effect of the SOD mimetic drug tempol on anti-GBM-GN in mice. 129/svJ mice were challenged with rabbit anti-mouse-GBM sera to induce GN and subsequently divided into tempol (200 mg x [kg.sup.-1] x [day.sup.-1], orally) and vehicle-treated groups. Routine histology, SOD and catalase activities, malondialdehyde (MDA), [H.sub.2][O..sub.2], and immunohistochemical staining for neutrophils, lymphocytes, macrophages, p65-NF-[kappa]B, and osteopontin were performed. Mice with anti-GBM-GN had significantly reduced renal SOD and catalase activities and increased H202 and MDA levels. Unexpectedly, tempol administration exacerbated anti-GBM-GN as evidenced by intensification of proteinuria, the presence of severe crescentic GN with leukocyte influx, and accelerated mortality in the treated group. Tempol treatment raised SOD activity and [H.sub.2][O.sub.2] level in urine, upregulated p65-NF-[kappa]B and osteopontin in the kidney, but had no effect on renal catalase activity. Thus tempol aggravates antiGBM-GN by increasing production of [H.sub.2][O.sub.2] which is a potent NF-[kappa]B activator and as such can intensify inflammation and renal injury. This supposition is supported by increases seen in p65-NF-[kappa]B, osteopontin, and leukocyte influx in the kidneys of the tempol-treated group. oxidative stress; catalase; hydrogen peroxide; crescentic glomerulonephritis; NF-[kappa]B doi: 10.1152/ajprenal.00583.2009.

Nitric oxide synthase (NOS) depletion or inhibition reduces ventilator-induced lung injury (VILI), but the responsible mechanisms remain incompletely defined. The aim of this study was to elucidate the role of endothelial NOS, NOS3, in the pathogenesis of VILI in an in vivo mouse model. Wild-type and NOS3-deficient mice were ventilated with high-tidal volume ([HV.sub.T]; 40 ml/kg) for 4 h, with and without adding NO to the inhaled gas. Additional wild-type mice were pretreated with tetrahydrobiopterin and ascorbic acid, agents that can prevent NOS-generated superoxide production. Arterial blood gas tensions, histology, and lung mechanics were evaluated after 4 h of [HV.sub.T] ventilation. The concentration of protein, IgM, cytokines, malondialdehyde, and 8-isoprostane were measured in bronchoalveolar lavage fluid (BALF). Myeloperoxidase activity, total and oxidized glutathione levels, and NOS-derived superoxide production were measured in lung tissue homogenates. [HV.sub.T] ventilation induced VILI in wild-type mice, as reflected by decreased lung compliance, increased concentrations of protein and cytokines in BALF, and oxidative stress. All indices of VILI were ameliorated in NOS3-deficient mice. Augmenting pulmonary NO levels by breathing NO during mechanical ventilation did not increase lung injury in NOS3-deficient mice. [HV.sub.T] ventilation increased NOS-inhibitable superoxide production in lung extracts from wild-type mice but not in those from NOS3-deficient mice. Administration of tetrahydrobiopterin and ascorbic acid ameliorated VILI in wild-type mice. Our results indicate that NOS3 contributes to ventilator-induced lung injury via increased production of superoxide. superoxide; pulmonary edema; inflammation doi: 10.1152/ajplung.00341.2009.

ALS is a fatal motor neuron disease of adult onset. Neuroinflammation contributes to ALS disease progression; however, the inflammatory trigger remains unclear. We report that ALS--linked mutant superoxide dismutase 1 (SOD1) activates caspase-1 and IL-1[beta] in microglia. Cytoplasmic accumulation of mutant SOD1 was sensed by an ASC containing inflammasome and antagonized by autophagy, limiting caspase-1-mediated inflammation. Notably, mutant SOD1 induced IL-1[beta] correlated with amyloid-like misfolding and was independent of dismutase activity. Deficiency in caspase-1 or IL-1[beta] or treatment with recombinant IL-1 receptor antagonist (IL-1RA) extended the lifespan of G93A-SOD1 transgenic mice and attenuated inflammatory pathology. These findings identify microglial IL-1[beta] as a causative event of neuroinflammation and suggest IL-1 as a potential therapeutic target in ALS. caspase-1 | inflammasome | interleukin 1 | Lou Gehrig's disease | neurodegeneration doi/ 10.1073/pnas.1002396107

Inhaled nitric oxide is being evaluated as a preventative therapy for patients at risk for bronchopulmonary dysplasia (BPD). Nitric oxide (NO), in the presence of superoxide, forms peroxynitrite, which reacts with tyrosine residues on proteins to form 3-nitrotyrosine (3-NT). However, NO can also act as an antioxidant and was recently found to improve the oxidative balance in preterm infants. Thus, we tested the hypothesis that the addition of a therapeutically relevant concentration (10 ppm) of NO to a hyperoxic exposure would lead to decreased 3-NT formation in the lung. FVB mouse pups were exposed to either room air (21% [O.sub.2]) or >95% [O.sub.2] with or without 10 ppm NO within 24 h of birth. In the first set of studies, body weights and survival were monitored for 7 days, and exposure to >95% [O.sub.2] resulted in impaired weight gain and near 100% mortality by 7 days. However, the mortality occurred earlier in pups exposed to >95% [O.sub.2] + NO than in pups exposed to > 95% [O.sub.2] alone. In a second set of studies, lungs were harvested at 72 h. Immunohistochemistry of the lungs at 72 h revealed that the addition of NO decreased alveolar, bronchial, and vascular 3-NT staining in pups exposed to both room air and hyperoxia. The lung nitrite levels were higher in animals exposed to > 95% oxygen + NO than in animals exposed to >95% oxygen alone. The protein levels of myeloperoxidase, monocyte chemotactic protein-1, and intracellular adhesion molecule-1 were assessed after 72 h of exposure and found to be greatest in the lungs of pups exposed to > 95% [O.sub.2].This hyperoxia-induced protein expression was significantly attenuated by the addition of 10 ppm NO. We propose that in the presence of> 95% [O.sub.2], peroxynitrite formation results in protein nitration; however, adding excess NO to the > 95% [O.sub.2] exposure prevents 3-NT formation by NO reacting with peroxynitrite to produce nitrite and N [O.sub.2].We speculate that the decreased protein nitration observed with the addition of NO may be a potential mechanism limiting hyperoxic lung injury. Keywords Protein nitration * Peroxynitrite * Lung injury * Oxygen toxicity, Introduction Inhaled nitric oxide (iNO) is a selective pulmonary vasodilator approved for the treatment of term and near-term neonates with hypoxic respiratory failure associated with evidence of pulmonary hypertension. The [...]

Alzheimer's disease (AD) is a neurodegenerative disease characterized by impaired cognitive function and the deposition of extracellular amyloid plaques and intracellular tangles. Although the proximal cause of AD is not well understood, it is clear that amyloid-[beta](A[beta]) plays a critical role in AD pathology. Recent studies also implicate mitochondrial abnormalities in AD. We investigated this idea by crossing mice that overexpress mitochondrial superoxide dismutase (SOD-2) with the Tg2576 mouse model of AD that overexpresses the human amyloid precursor protein carrying the Swedish mutation (K670N:M671L). We found that overexpression of SOD-2 decreased hippocampal superoxide, prevented AD-related learning and memory deficits, and reduced A[beta] plaques. Interestingly, SOD-2 overexpression did not affect the absolute levels of A[[beta].sub.1-40] and A[[beta].sub.1-42], but did significantly reduce the A[[beta].sub.1-42] to A[[beta].sub.1-40] ratio, thereby shifting the balance toward a less amyloidogenic A[beta] composition. These findings directly link mitochondrial superoxide to AD pathology and demonstrate the beneficial effects of a mitochondrial anti-oxidant enzyme, hence offering significant therapeutic implications for AD. antioxidant | dementia | mitochondria | oxidative stress | reactive oxygen species

The long-term effects of uncoupled mitochondrial respiration by uncoupling protein-2 (UCP2) in mammalian physiology remain controversial. Here we show that increased mitochondrial uncoupling activity of different tissues predicts longer lifespan of rats compared with mice. UCP2 reduces reactive oxygen species (ROS) production and oxidative stress throughout the aging process in different tissues in mice. The absence of UCP2 shortens lifespan in wild-type mice, and the level of UCP2 positively correlates with the postnatal survival of superoxide dismutase-2 mutant animals. Thus UCP2 has a beneficial influence on cell and tissue function leading to increased lifespan. reactive oxygen species; mitochondria; superoxide dismutase-2; longevity; aging; fatty acid oxidation

Dysregulation in central nervous system (CNS) signaling that results in chronic sympathetic hyperactivity is now recognized to play a critical role in the pathogenesis of heart failure (HF) following myocardial infarction (MI). We recently demonstrated that adenovirus-mediated gene transfer of cytoplasmic superoxide dismutase (Ad-Cu/ZnSOD) to forebrain circumventricular organs, unique sensory structures that lack a blood-brain barrier and link peripheral blood-borne signals to central nervous system cardiovascular circuits, inhibits both the MI-induced activation of these central signaling pathways and the accompanying sympathoexcitation. Here, we tested the hypothesis that this forebrain-targeted reduction in oxidative stress translates into amelioration of the post-MI decline in myocardial function and increase in mortality. Adult C57BL/6 mice underwent left coronary artery ligation or sham surgery along with forebrain-targeted gene transfer of Ad-Cu/ZnSOD or a control vector. The results demonstrate marked MI-induced increases in superoxide radical formation in one of these forebrain regions, the subfornical organ (SFO). Ad-Cu/ZnSOD targeted to this region abolished the increased superoxide levels and led to significantly improved myocardial function compared with control vector-treated mice. This was accompanied by diminished levels of cardiomyocyte apoptosis in the Ad-Cu/ZnSOD but not the control vector-treated group. These effects of superoxide scavenging with Ad-Cu/ZnSOD in the forebrain paralleled increased post-MI survival rates compared with controls. This suggests that oxidative stress in the SFO plays a critical role in the deterioration of cardiac function following MI and underscores the promise of CNS-targeted antioxidant therapy for the treatment of MI-induced HF. heart failure; antioxidant gene therapy; survival; sympathetic nervous system

Matrix metalloprotease-9 (MMP-9) is increased in lung injury following hyperoxia exposure in neonatal mice, in association with impaired alveolar development. We studied the role of MMP-9 in the mechanism of hyperoxia-induced functional and histological changes in neonatal mouse lung. Reduced alveolarization with remodeling of ECM is a major morbidity component of oxidant injury in developing lung. MMP-9 mediates oxidant injury in developing lung causing altered lung remodeling. Five-day-old neonatal wild-type (WT) and MMP-9 (-/-) mice were exposed to hyperoxia for 8 days. The lungs were inflation fixed, and sections were examined for morphometry. The mean linear intercept and alveolar counts were evaluated. Immunohistochemistry for MMP-9 and elastin was performed. MMP-2, MMP-9, type I collagen, and tropoelastin were measured by Western blot analysis. Lung quasistatic compliance was studied in anaesthetized mice. MMP-2 and MMP-9 were significantly increased in lungs of WT mice exposed to hyperoxia compared with controls. Immunohistochemistry showed an increase in MMP-9 in mesenchyme and alveolar epithelium of hyperoxic lungs. The lungs of hyperoxia-exposed WT mice had less gas exchange surface area and were less compliant compared with room air-exposed WT and hyperoxia-exposed MMP-9 (-/-) mice. Type I collagen and tropoelastin were increased in hyperoxia-exposed WT with aberrant elastin staining. These changes were ameliorated in hyperoxia-exposed MMP-9 (-/-) mice. MMP-9 plays an important role in the structural changes consequent to oxygen-induced lung injury. Blocking MMP-9 activity may lead to novel therapeutic approaches in preventing bronchopulmonary dysplasia. morphometry; elastin; bronchopulmonary dysplasia

Insulin resistance is well established as an independent risk factor for the development of type 2 diabetes and cardiovascular atherosclerosis. Most studies have examined atherogenesis in models of severe insulin resistance or diabetes. However, by the time of diagnosis, individuals with type 2 diabetes already demonstrate a significant atheroma burden. Furthermore, recent studies suggest that, even in adolescence, insulin resistance is a progressive disorder that increases cardiovascular risk. In the present report, we studied early mechanisms of reduction in the bioavailability of the antiatheroscerotic molecule nitric oxide (NO) in very mild insulin resistance. Mice with haploinsufficiency for the insulin receptor (IRKO) are a model of mild insulin resistance with preserved glycemic control. We previously demonstrated that 2-mo, (Young) IRKO mice have preserved vasorelaxation responses to ACh. This remained the case at 4 mo of age. However, by 6 mo, despite no significant deterioration in glucose homeostasis (Adult), IRKO mice had marked blunting of ACh-mediated vasorelaxation [IRKO maximum contraction response ([E.sub.max]) 66 [+ or -] 5% vs. wild type 87 [+ or -] 4%, P < 0.01]. Despite the endothelial dysfunction demonstrated, aortic endothelial nitric oxide synthase (eNOS) mRNA levels were similar in Adult IRKO and wild-type mice, and, interestingly, aortic eNOS protein levels were increased, suggesting a compensatory upregulation in the IRKO. We then examined the potential role of reactive oxygen species in mediating early endothelial dysfunction. The superoxide dismutase mimetic Mn(III)tetrakis(1-methyl-4-pyridyl) porphyrin pentachloride (MnTMPyP) restored ACh relaxation responses in the Adult IRKO ([E.sub.max] to ACh with MnTMPyP 85 [+ or -] 5%). Dihydroethidium fluorescence of aortas and isolated coronary microvascular endothelial cells confirmed a substantial increase in endothelium-derived reactive oxygen species in IRKO mice. These data demonstrate that mild insulin resistance is a potent substrate for accelerated endothelial dysfunction and support a role for endothelial cell superoxide production as a mechanism underlying the early reduction in NO bioavailability. insulin resistance; endothelial function; superoxide; enos

Male Sprague-Dawley rats were maintained on a low-salt (LS) diet (0.4% NaCl) or changed to a high-salt (HS) diet (4% NaCl) for 3 days. Increases in intracellular [Ca.sup.2+] ([[[Ca.sup.2+]].sub.i]) in response to methacholine (10 [micro]M) and histamine (10 [micro]M) were significantly attenuated in aortic endothelial cells from rats fed a HS diet, whereas thapsigargin (10 [micro]M)-induced increases in [[[Ca.sup.2+]].sub.i] were unaffected. Methacholine-induced nitric oxide (NO) production was eliminated in endothelial cells of aortas from rats fed a HS diet. Low-dose ANG II infusion (5 ng x [kg.sup.-1] x [min.sup.-1] iv) for 3 days prevented impaired [[[Ca.sup.2+]].sub.i] signaling response to methacholine and histamine and restored methacholine-induced NO production in aortas from rats on a HS diet. Adding Tempol (500 [micro]M) to the tissue bath to scavenge superoxide anions increased NO release and caused [N.sup.[omega]]-nitro-L-arginine methyl ester-sensitive vascular relaxation in aortas from rats fed a HS diet but had no effect on methacholine-induced [Ca.sup.2+] responses. Chronic treatment with Tempol (1 mM) in the drinking water restored NO release, augmented vessel relaxation, and increased methacholine-induced [Ca.sup.2+] responses significantly in aortas from rats on a HS diet hut not in aortas from rats on a LS diet. These findings suggest that 1) agonist-induced [Ca.sup.2+] responses and NO levels are reduced in aortas of rats on a HS diet; 2) increased vascular superoxide levels contribute to NO destruction, and, eventually, to impaired [Ca.sup.2+] signaling in the vascular endothelial cells; and 3) reduced circulating ANG II levels during elevated dietary salt lead to elevated superoxide levels, impaired endothelial [Ca.sup.2+] signaling, and reduced NO production in the endothelium. endothelium; sodium; dietary salt intake; vascular relaxation; nitric oxide doi:10.1152/ajpheart.00692.2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.tips.2006.03.009 Byline: Maria Teresa CarrA[logical not] (a)(b), Giuliano Grignaschi (c), Caterina Bendotti (c) Abstract: Amyotrophic lateral sclerosis (ALS) is an incurable disease that arises from the progressive loss of motoneurons. Even when caused by a single gene defect, as in the case of mutations in the enzyme Cu-Zn superoxide dismutase (SOD1), ALS is the result of a complex cascade that involves crosstalk among motoneurons, glia and muscles, and evolves through the action of converging toxic mechanisms. Transgenic rodents that express human mutant SOD1 and develop a progressive paralytic disease are widely used to screen potential therapeutics. Treatments that interfere with a specific event in the neurotoxic cascade have been reported to produce a modest increase in rodent lifespan. Multi-intervention approaches, including novel methods to intercept the damage and to deliver molecules to vulnerable cells, have recently been shown to be more effective. Thus, new avenues for promising therapeutic approaches can be derived from multidrug treatments and/or the delivery of growth factors by viral vectors, in combination with exercise and/or diet regimens. Author Affiliation: (a) Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, Rome 00133, Italy (b) Fondazione Santa Lucia, Centro Europeo di Ricerca sul Cervello, Via del Fosso di Fiorano 64, 00143 Rome, Italy (c) Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, Via Eritrea 62, 20157 Milan, Italy

Hypertonicity activates the transcription factor tonicity-responsive enhancer/ osmotic response element binding protein (TonEBP/OREBP), resulting in increased expression of genes involved in osmoprotective accumulation of organic osmolytes, including glycine betaine, and in increased expression of osmoprotective heat shock proteins. Our previous studies showed that high NaCI increases reactive oxygen species (ROS), which contribute to activation of TonEBP/OREBP. Mitochondria are a major source of ROS. The purpose of the present study was to examine whether mitochondria produce the ROS that contribute to activation of TonEBP/OREBP. We inhibited mitochondrial ROS production in HEK293 cells with rotenone and myxothiazol, which inhibit mitochondrial complexes I and III, respectively. Rotenone (250 nM) and myxothiazol (12 nM) reduce high NaCl induced ROS over 40%, whereas apocynin (100 [micro]M), an inhibitor of NADPH oxidase, and allopurinol (100 [micro]M), an inhibitor of xanthine oxidase, have no significant effect. Rotenone and myxothiazol reduce high NaCl-induced increases in TonEBP/OREBP transcriptional activity (ORE/TonE reporter assay) and BGTI (betaine transporter) mRNA abundance ranging from 53 to 69%. They inhibit high NaCl induced TonEBP/OREBP transactivating activity, but not its nuclear translocation. Release of ATP into the medium on hypertonic stress has been proposed to be a signal that triggers cellular osmotic responses. However, we do not detect release of ATP into the medium or inhibition of high NaCl-induced ORE/TonE reporter activity by an ATPase, apyrase (20 U/ml), indicating that high NaCl-induced activation of TonEBP/OREBP is not mediated by release of ATP. We conclude that high NaCl increases mitochondrial ROS production, which contributes to the activation of TonEBP/OREBP by increasing its transactivating activity. superoxides; rotenone: myxothiazol: transactivation; nuclear translocation; ATP release

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.tips.2005.04.003 Byline: Pal Pacher (a), Richard Schulz (b), Lucas Liaudet (c), Csaba Szabo (d)(e)(f) Abstract: Dysregulation of nitric oxide (NO) and increased oxidative and nitrosative stress are implicated in the pathogenesis of heart failure. Peroxynitrite is a reactive oxidant that is produced from the reaction of nitric oxide with superoxide anion and impairs cardiovascular function through multiple mechanisms, including activation of matrix metalloproteinases (MMPs) and nuclear enzyme poly(ADP-ribose) polymerase (PARP). Recent studies suggest that the neutralization of peroxynitrite or pharmacological inhibition of MMPs and PARP are promising new approaches in the experimental therapy of various forms of myocardial injury. In this article, the role of nitrosative stress and downstream mechanisms, including activation of MMPs and PARP, in various forms of heart failure are discussed and novel emerging therapeutic strategies offered by neutralization of peroxynitrite and inhibition of MMPs and PARP in these pathophysiological conditions are reviewed. Author Affiliation: (a) National Institutes of Health, NIAAA, Laboratory of Physiological Studies, 5625 Fishers Lane MSC 9413, Room 2S24, Bethesda, MD 20892-9413, USA (b) Departments of Pharmacology and Pediatrics, Cardiovascular Research Group, University of Alberta, Edmonton, Alberta, Canada (c) Division of Critical Care, Department of Internal Medicine, University Hospital, Lausanne, Switzerland (d) Department of Surgery, UMD NJ-New Jersey Medical School, Newark, NJ 07103, USA (e) Department of Human Physiology and Clinical Experimental Research, Semmelweis University Medical School, Budapest, Hungary (f) Inotek Pharmaceuticals, Beverly, MA 01915, USA

Ageing and lifespan of organisms are determined by complicated interactions between their genetics and the environment, but the cellular mechanisms remain controversial; several studies suggest that cellular energy metabolism and [...]

The production of superoxide by phagocyte NADPH oxidase is crucial in the fight against infection with microorganisms. Its superoxide-producing cytochrome core comprises heterodimers of [p22.sup.phox] and [gp91.sup.phox], and inactivation of [...]