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Sample records for activated nitric oxide

  1. Enhanced colonic nitric oxide generation and nitric oxide synthase activity in ulcerative colitis and Crohn's disease.

    PubMed Central

    Rachmilewitz, D; Stamler, J S; Bachwich, D; Karmeli, F; Ackerman, Z; Podolsky, D K

    1995-01-01

    Recent studies have suggested that nitric oxide (NO.), the product of nitric oxide synthase in inflammatory cells, may play a part in tissue injury and inflammation through its oxidative metabolism. In this study the colonic generation of oxides of nitrogen (NOx) and nitric oxide synthase activity was determined in ulcerative colitis and Crohn's disease. Colonic biopsy specimens were obtained from inflammatory bowel disease patients and from normal controls. Mucosal explants were cultured in vitro for 24 hours and NOx generation was determined. Nitric oxide synthase activity was monitored by the conversion of [3H]-L-arginine to citrulline. Median NOx generation by inflamed colonic mucosa of patients with active ulcerative colitis and Crohn's colitis was 4.2- and 8.1-fold respectively higher than that by normal human colonic mucosa. In ulcerative colitis and Crohn's colitis nitric oxide synthase activity was 10.0- and 3.8-fold respectively higher than in normal subjects. Colonic NOx generation is significantly decreased by methylprednisolone and ketotifen. The decrease in NOx generation by cultured colonic mucosa induced by methylprednisolone suggests that NO synthase activity is induced during the culture and the steroid effect may contribute to its therapeutic effect. Enhanced colonic NOx generation by stimulated nitric oxide synthase activity in ulcerative colitis and Crohn's disease may contribute to tissue injury. PMID:7541008

  2. Dexmedetomidine inhibits vasoconstriction via activation of endothelial nitric oxide synthase

    PubMed Central

    Nong, Lidan; Ma, Jue; Zhang, Guangyan; Deng, Chunyu; Mao, Songsong; Li, Haifeng

    2016-01-01

    Despite the complex vascular effects of dexmedetomidine (DEX), its actions on human pulmonary resistance arteries remain unknown. The present study tested the hypothesis that DEX inhibits vascular tension in human pulmonary arteries through the endothelial nitric oxide synthase (eNOS) mediated production of nitric oxide (NO). Pulmonary artery segments were obtained from 62 patients who underwent lung resection. The direct effects of DEX on human pulmonary artery tension and changes in vascular tension were determined by isometric force measurements recorded on a myograph. Arterial contractions caused by increasing concentrations of serotonin with DEX in the presence or absence of L-NAME (endothelial nitric oxide synthase inhibitor), yohimbine (α2-adrenoceptor antagonist) and indomethacin (cyclooxygenase inhibitor) as antagonists were also measured. DEX had no effect on endothelium-intact pulmonary arteries, whereas at concentrations of 10–8~10–6 mol/L, it elicited contractions in endothelium-denuded pulmonary arteries. DEX (0.3, 1, or 3×10–9 mmol/L) inhibited serotonin-induced contraction in arteries with intact endothelium in a dose-dependent manner. L-NAME and yohimbine abolished DEX-induced inhibition, whereas indomethacin had no effect. No inhibitory effect was observed in endothelium-denuded pulmonary arteries. DEX-induced inhibition of vasoconstriction in human pulmonary arteries is mediated by NO production induced by the activation of endothelial α2-adrenoceptor and nitric oxide synthase.

  3. Dexmedetomidine inhibits vasoconstriction via activation of endothelial nitric oxide synthase

    PubMed Central

    Nong, Lidan; Ma, Jue; Zhang, Guangyan; Deng, Chunyu; Mao, Songsong; Li, Haifeng

    2016-01-01

    Despite the complex vascular effects of dexmedetomidine (DEX), its actions on human pulmonary resistance arteries remain unknown. The present study tested the hypothesis that DEX inhibits vascular tension in human pulmonary arteries through the endothelial nitric oxide synthase (eNOS) mediated production of nitric oxide (NO). Pulmonary artery segments were obtained from 62 patients who underwent lung resection. The direct effects of DEX on human pulmonary artery tension and changes in vascular tension were determined by isometric force measurements recorded on a myograph. Arterial contractions caused by increasing concentrations of serotonin with DEX in the presence or absence of L-NAME (endothelial nitric oxide synthase inhibitor), yohimbine (α2-adrenoceptor antagonist) and indomethacin (cyclooxygenase inhibitor) as antagonists were also measured. DEX had no effect on endothelium-intact pulmonary arteries, whereas at concentrations of 10–8~10–6 mol/L, it elicited contractions in endothelium-denuded pulmonary arteries. DEX (0.3, 1, or 3×10–9 mmol/L) inhibited serotonin-induced contraction in arteries with intact endothelium in a dose-dependent manner. L-NAME and yohimbine abolished DEX-induced inhibition, whereas indomethacin had no effect. No inhibitory effect was observed in endothelium-denuded pulmonary arteries. DEX-induced inhibition of vasoconstriction in human pulmonary arteries is mediated by NO production induced by the activation of endothelial α2-adrenoceptor and nitric oxide synthase. PMID:27610030

  4. Dexmedetomidine inhibits vasoconstriction via activation of endothelial nitric oxide synthase.

    PubMed

    Nong, Lidan; Ma, Jue; Zhang, Guangyan; Deng, Chunyu; Mao, Songsong; Li, Haifeng; Cui, Jianxiu

    2016-09-01

    Despite the complex vascular effects of dexmedetomidine (DEX), its actions on human pulmonary resistance arteries remain unknown. The present study tested the hypothesis that DEX inhibits vascular tension in human pulmonary arteries through the endothelial nitric oxide synthase (eNOS) mediated production of nitric oxide (NO). Pulmonary artery segments were obtained from 62 patients who underwent lung resection. The direct effects of DEX on human pulmonary artery tension and changes in vascular tension were determined by isometric force measurements recorded on a myograph. Arterial contractions caused by increasing concentrations of serotonin with DEX in the presence or absence of L-NAME (endothelial nitric oxide synthase inhibitor), yohimbine (α2-adrenoceptor antagonist) and indomethacin (cyclooxygenase inhibitor) as antagonists were also measured. DEX had no effect on endothelium-intact pulmonary arteries, whereas at concentrations of 10(-8)~10(-6) mol/L, it elicited contractions in endothelium-denuded pulmonary arteries. DEX (0.3, 1, or 3×10(-9) mmol/L) inhibited serotonin-induced contraction in arteries with intact endothelium in a dose-dependent manner. L-NAME and yohimbine abolished DEX-induced inhibition, whereas indomethacin had no effect. No inhibitory effect was observed in endothelium-denuded pulmonary arteries. DEX-induced inhibition of vasoconstriction in human pulmonary arteries is mediated by NO production induced by the activation of endothelial α2-adrenoceptor and nitric oxide synthase. PMID:27610030

  5. Nitric oxide

    Integrated Risk Information System (IRIS)

    Nitric oxide ; CASRN 10102 - 43 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  6. Nitric oxide mediates caerulein-induced suppression of locomotor activity.

    PubMed

    Volke, V; Soosaar, A; Kõks, S; Bourin, M; Männistö, P T; Vasar, E

    1996-08-01

    Caerulein, a non-selective agonist of cholecystokinin (CCK) receptors, is shown to suppress locomotor activity in rodents via stimulation of CCK(A) receptors. In the present study we examined the possible involvement of nitric oxide (NO) in caerulein-induced hypolocomotion in rats. Caerulein (10 microg/kg) markedly decreased the horizontal and vertical components of locomotor activity in rats measured in dark motility boxes. Pretreatment with a nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME), at 5 mg/kg i.p., abolished the inhibiting action of caerulein on the horizontal activity, but did not affect the reduced frequency of rearing. The other doses of L-NAME (1, 10 and 20 mg/kg) were ineffective against caerulein. As L-NAME at this dose range does not stimulate locomotor activity, it is likely that NO is involved in the motor suppressant effect of systemically administered caerulein.

  7. Antioxidant and nitric oxide inhibition activities of Thai medicinal plants.

    PubMed

    Makchuchit, Sunita; Itharat, Arunporn; Tewtrakul, Supinya

    2010-12-01

    Nineteen Thai medicinal plants used in Thai traditional medicine preparation to treat colds, asthma and fever were studied for their antioxidant and NO inhibitory activities. Three extracts were obtained from each plant. First extract obtained by macerating the plant part in 95% ethanol (Et) residue was boiled in water, where water extract (EW) was obtained. The third extract (HW) was obtained by boiling each plant in water similar to that of Thai traditional medicine practice. These extracts were tested for their antioxidant activity using DPPH assay, and anti-inflammatory activity by determination of inhibitory activity on lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW 264.7 cell lines using Griess reagent. Results indicated that Et, EW and HW of Syzygium aromaticum showed the highest antioxidant activity (EC50 = 6.56, 4.73 and 5.30 microg/ml, respectively). Et of Atractylodes lancea exhibited the most potent inhibitory activity on lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW 264.7 cells, with IC50 value of 9.70 microg/ml, followed by Et of Angelica sinensis and Cuminum cyminum (IC50 = 12.52 and 13.56 microg/ml, respectively) but water extract (EW, HW) of all plants were apparently inactive. These results of anti-inflammatory activity of these plants correspond with the traditional use for fever; cold, allergic-related diseases and inflammatory-related diseases. PMID:21294419

  8. Pterins inhibit nitric oxide synthase activity in rat alveolar macrophages.

    PubMed Central

    Jorens, P. G.; van Overveld, F. J.; Bult, H.; Vermeire, P. A.; Herman, A. G.

    1992-01-01

    1. The synthesis of nitrite and citrulline from L-arginine by immune-stimulated rat alveolar macrophages and the modulation of this synthesis were studied. 2,4-Diamino-6-hydroxypyrimidine (DAHP), 6R-5,6,7,8-tetrahydro-L-biopterin (BH4) and L-sepiapterin were potent inhibitors of the recombinant interferon-gamma induced production of nitrogen oxides in intact cultured cells with I50 values for BH4 and L-sepiapterin of approximately 10 microM. They were equally effective in inhibiting the induced production of citrulline. This inhibitory effect was concentration-dependent for all three modulators investigated. 2. The inhibitory effects were not dependent on incubation times of either 24 or 48 h, on the immune-stimulus used (lipopolysaccharide, interferon-gamma), or whether these stimuli were added during or after the induction period. 3. Pterin-6-carboxylic acid (PCA), which cannot be converted into BH4, and methotrexate (MTX), which inhibits dihydrofolatereductase but not de novo biosynthesis of BH4, did not change the production of nitrite. 4. The data indicate that DAHP, an inhibitor of the de novo biosynthesis of the co-factor BH4, blocks the nitric oxide synthase activity in intact cells. Since the pterins BH4 and L-sepiapterin blocked the L-arginine dependent production of nitrite and citrulline, the activity of nitric oxide synthase in phagocytic cells may be regulated by metabolic endproducts of the de novo biosynthesis of BH4. PMID:1281717

  9. Nitric oxide inhibition strategies

    PubMed Central

    Wong, Vivian (Wai Chong); Lerner, Ethan

    2015-01-01

    Nitric oxide is involved in many physiologic processes. There are efforts, described elsewhere in this volume, to deliver nitric oxide to tissues as a therapy. Nitric oxide also contributes to pathophysiologic processes. Inhibiting nitric oxide or its production can thus also be of therapeutic benefit. This article addresses such inhibitory strategies. PMID:26634146

  10. Nitric oxide in the bovine oviduct: influence on contractile activity and nitric oxide synthase isoforms localization.

    PubMed

    Yilmaz, O; Całka, J; Bukowski, R; Zalecki, M; Wasowicz, K; Jaroszewski, J J; Markiewicz, W; Bulbul, A; Ucar, M

    2012-04-15

    The oviducts of 64 Holstein cows in luteal (early I, early II and late) and follicular phases were evaluated to determine the protein expression and mRNA transcription of different nitric oxide synthase isoforms (eNOS, iNOS, nNOS) as well as the effect of nitric oxide (NO) on spontaneous contractility in vitro. The expression patterns of nitric oxide synthase (NOS) isoforms in isthmus and ampulla (n = 6 for each phase) were determined by immunohistochemistry, reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot analysis. In the contractility studies, longitudinal and circular isolated strips of isthmus and ampulla (n = 10 for each phase) of oviducts located ipsilateral to the luteal structure or preovulatory follicle were treated as follows: a) L-arginine, an endogenous NO donor (10(-8) to 10(-3)m), b) N(ω)-nitro-L-arginine methyl ester (L-NAME), a NOS inhibitor (10(-5)m) and L-arginine (10(-3)m), c) methylene blue (MB), an inhibitor of soluble guanylate (10(-5)m) and L-arginine (10(-3)m) and d) sodium nitroprusside (SNP), an exogenous NO donor (10(-8) to 10(-4)m). Immunohistochemical evaluation revealed that endothelial NOS (eNOS) expression detected in epithelial layer of isthmus and ampulla was strong in early I luteal phase, moderate in follicular phase and weak in other phases. Neuronal NOS (nNOS) immunoreactivity was strong in isthmus and moderate in ampulla, and staining of nerve fibers was observed mostly in early I luteal and follicular phases. All eNOS, nNOS and inducible NOS (iNOS) isoforms were detected by RT-PCR. eNOS and iNOS proteins were evident, whereas nNOS was undetectable by Western blot analysis in the tissue examined. L-arginine applied alone or after L-NAME did not alter or increase the contractile tension of the strips in most tissues examined. However, L-arginine applied after MB increased contractile tension in the strips of ampulla and longitudinal isthmus from early I luteal phase and circular isthmus from

  11. Visualisation of nitric oxide generated by activated murine macrophages.

    PubMed

    Leone, A M; Furst, V W; Foxwell, N A; Cellek, S; Moncada, S

    1996-04-01

    We have visualised the release and approximate diffusion profile of nitric oxide (NO) from activated murine macrophages using a high transmission microscope coupled to a high sensitivity photon counting camera. The images generated by NO were cell-associated and spread over an area of approximately 175 micrometers from the activated macrophage. The signals obtained were dependent on the presence of exogenous L-arginine in the medium and followed a time course similar to that previously described for the generation of NO by the inducible form of NO synthase. The light signal was attenuated by the inhibitor of NO synthase, N omega-nitro-L-arginine methyl ester. Studies using superoxide-deficient macrophages further confirmed that the signals detected were generated by NO rather than reactive oxygen intermediates. PMID:8660339

  12. Natural Product Nitric Oxide Chemistry: New Activity of Old Medicines

    PubMed Central

    Jiang, Hong; Torregrossa, Ashley C.; Parthasarathy, Deepa K.; Bryan, Nathan S.

    2012-01-01

    The use of complementary and alternative medicine (CAM) as a therapy and preventative care measure for cardiovascular diseases (CVD) may prove to be beneficial when used in conjunction with or in place of conventional medicine. However, the lack of understanding of a mechanism of action of many CAMs limits their use and acceptance in western medicine. We have recently recognized and characterized specific nitric oxide (NO) activity of select alternative and herbal medicines that may account for many of their reported health benefits. The ability of certain CAM to restore NO homeostasis both through enhancing endothelial production of NO and by providing a system for reducing nitrate and nitrite to NO as a compensatory pathway for repleting NO bioavailability may prove to be a safe and cost-effective strategy for combating CVD. We will review the current state of science behind NO activity of herbal medicines and their effects on CVD. PMID:22548122

  13. Flavone inhibits nitric oxide synthase (NOS) activity, nitric oxide production and protein S-nitrosylation in breast cancer cells

    SciTech Connect

    Zhu, Wenzhen; Yang, Bingwu; Fu, Huiling; Ma, Long; Liu, Tingting; Chai, Rongfei; Zheng, Zhaodi; Zhang, Qunye; Li, Guorong

    2015-03-13

    As the core structure of flavonoids, flavone has been proved to possess anticancer effects. Flavone's growth inhibitory functions are related to NO. NO is synthesized by nitric oxide synthase (NOS), and generally increased in a variety of cancer cells. NO regulates multiple cellular responses by S-nitrosylation. In this study, we explored flavone-induced regulations on nitric oxide (NO)-related cellular processes in breast cancer cells. Our results showed that, flavone suppresses breast cancer cell proliferation and induces apoptosis. Flavone restrains NO synthesis by does-dependent inhibiting NOS enzymatic activity. The decrease of NO generation was detected by fluorescence microscopy and flow cytometry. Flavone-induced inhibitory effect on NOS activity is dependent on intact cell structure. For the NO-induced protein modification, flavone treatment significantly down-regulated protein S-nitrosylation, which was detected by “Biotin-switch” method. The present study provides a novel, NO-related mechanism for the anticancer function of flavone. - Highlights: • Flavone inhibits proliferation and induces apoptosis in MCF-7 cells. • Flavone decreases nitric oxide production by inhibiting NOS enzymatic activity in breast cancer cells. • Flavone down-regulates protein S-nitrosylation.

  14. Biosynthesis of nitric oxide activates iron regulatory factor in macrophages.

    PubMed

    Drapier, J C; Hirling, H; Wietzerbin, J; Kaldy, P; Kühn, L C

    1993-09-01

    Biosynthesis of nitric oxide (NO) from L-arginine modulates activity of iron-dependent enzymes, including mitochondrial acontiase, an [Fe-S] protein. We examined the effect of NO on the activity of iron regulatory factor (IRF), a cytoplasmic protein which modulates both ferritin mRNA translation and transferrin receptor mRNA stability by binding to specific mRNA sequences called iron responsive elements (IREs). Murine macrophages were activated with interferon-gamma and lipopolysaccharide to induce NO synthase activity and cultured in the presence or absence of NG-substituted analogues of L-arginine which served as selective inhibitors of NO synthesis. Measurement of the nitrite concentration in the culture medium was taken as an index of NO production. Mitochondria-free cytosols were then prepared and aconitase activity as well as IRE binding activity and induction of IRE binding activity were correlated and depended on NO synthesis after IFN-gamma and/or LPS stimulation. Authentic NO gas as well as the NO-generating compound 3-morpholinosydnonimine (SIN-1) also conversely modulated aconitase and IRE binding activities of purified recombinant IRF. These results provide evidence that endogenously produced NO may modulate the post-transcriptional regulation of genes involved in iron homeostasis and support the hypothesis that the [Fe-S] cluster of IRF mediates iron-dependent regulation. PMID:7504626

  15. Protein kinase D activity controls endothelial nitric oxide synthesis.

    PubMed

    Aicart-Ramos, Clara; Sánchez-Ruiloba, Lucía; Gómez-Parrizas, Mónica; Zaragoza, Carlos; Iglesias, Teresa; Rodríguez-Crespo, Ignacio

    2014-08-01

    Vascular endothelial growth factor (VEGF) regulates key functions of the endothelium, such as angiogenesis or vessel repair in processes involving endothelial nitric oxide synthase (eNOS) activation. One of the effector kinases that become activated in endothelial cells upon VEGF treatment is protein kinase D (PKD). Here, we show that PKD phosphorylates eNOS, leading to its activation and a concomitant increase in NO synthesis. Using mass spectrometry, we show that the purified active kinase specifically phosphorylates recombinant eNOS on Ser1179. Treatment of endothelial cells with VEGF or phorbol 12,13-dibutyrate (PDBu) activates PKD and increases eNOS Ser1179 phosphorylation. In addition, pharmacological inhibition of PKD and gene silencing of both PKD1 and PKD2 abrogate VEGF signaling, resulting in a clear diminished migration of endothelial cells in a wound healing assay. Finally, inhibition of PKD in mice results in an almost complete disappearance of the VEGF-induced vasodilatation, as monitored through determination of the diameter of the carotid artery. Hence, our data indicate that PKD is a new regulatory kinase of eNOS in endothelial cells whose activity orchestrates mammalian vascular tone. PMID:24928905

  16. Nitric oxide induces caspase activity in boar spermatozoa.

    PubMed

    Moran, J M; Madejón, L; Ortega Ferrusola, C; Peña, F J

    2008-07-01

    Nitric oxide (NO) is a highly reactive free radical that plays a key role in intra- and intercellular signaling. Production of radical oxygen species and an apoptotic-like phenomenon have recently been implicated in cryodamage during sperm cryopreservation. The objective of the present study was to evaluate the effect of sodium nitroprusside (SNP), an NO donor, on boar sperm viability. Semen samples were pooled from four boars that were routinely used for artificial insemination. Flow cytometry was used to compare semen incubated with SNP to control semen. Specifically, NO production was measured using the NO indicator dye diaminofluorescein diacetate, and caspase activity was determined using the permeable pan-caspase inhibitor Z-VAD linked to FITC. SNP induced a significant increase in the percentage of sperm cells showing caspase activity, from 9.3% in control samples to 76.2% in SNP-incubated samples (P<0.01). This study suggests that NO is a major free radical involved in boar sperm damage. PMID:18433854

  17. NOpiates: Novel Dual Action Neuronal Nitric Oxide Synthase Inhibitors with μ-Opioid Agonist Activity

    PubMed Central

    2012-01-01

    A novel series of benzimidazole designed multiple ligands (DMLs) with activity at the neuronal nitric oxide synthase (nNOS) enzyme and the μ-opioid receptor was developed. Targeting of the structurally dissimilar heme-containing enzyme and the μ-opioid GPCR was predicated on the modulatory role of nitric oxide on μ-opioid receptor function. Structure–activity relationship studies yielded lead compound 24 with excellent nNOS inhibitory activity (IC50 = 0.44 μM), selectivity over both endothelial nitric oxide synthase (10-fold) and inducible nitric oxide synthase (125-fold), and potent μ-opioid binding affinity, Ki = 5.4 nM. The functional activity as measured in the cyclic adenosine monosphospate secondary messenger assay resulted in full agonist activity (EC50 = 0.34 μM). This work represents a novel approach in the development of new analgesics for the treatment of pain. PMID:24900459

  18. Sympathetic activation and nitric oxide function in early hypertension

    PubMed Central

    Okamoto, Luis E.; Diedrich, André; Choi, Leena; Robertson, David; Farley, Ginnie; Paranjape, Sachin; Biaggioni, Italo

    2012-01-01

    The purpose of this study was to determine if tonic restrain of blood pressure by nitric oxide (NO) is impaired early in the development of hypertension. Impaired NO function is thought to contribute to hypertension, but it is not clear if this is explained by direct effects of NO on vascular tone or indirect modulation of sympathetic activity. We determined the blood pressure effect of NO synthase inhibition with Nω-monomethyl-l-arginine (l-NMMA) during autonomic blockade with trimethaphan to eliminate baroreflex buffering and NO modulation of autonomic tone. In this setting, impaired NO modulation of vascular tone would be reflected as a blunted pressor response to l-NMMA. We enrolled a total of 66 subjects (39 ± 1.3 yr old, 30 females), 20 normotensives, 20 prehypertensives (blood pressure between 120/80 and 140/90 mmHg), 17 hypertensives, and 9 smokers (included as “positive” controls of impaired NO function). Trimethaphan normalized blood pressure in hypertensives, suggesting increased sympathetic tone contributing to hypertension. In contrast, l-NMMA produced similar increases in systolic blood pressure in normal, prehypertensive, and hypertensive subjects (31 ± 2, 32 ± 2, and 30 ± 3 mmHg, respectively), whereas the response of smokers was blunted (16 ± 5 mmHg, P = 0.012). Our results suggest that sympathetic activity plays a role in hypertension. NO tonically restrains blood pressure by ∼30 mmHg, but we found no evidence of impaired modulation by NO of vascular tone contributing to the early development of hypertension. If NO deficiency contributes to hypertension, it is likely to be through its modulation of the autonomic nervous system, which was excluded in this study. PMID:22287587

  19. Nitric oxide and thiol redox regulation of Janus kinase activity

    PubMed Central

    Duhé, Roy J.; Evans, Gerald A.; Erwin, Rebecca A.; Kirken, Robert A.; Cox, George W.; Farrar, William L.

    1998-01-01

    The activation of Janus kinases (JAKs) is crucial for propagation of the proliferative response initiated by many cytokines. The proliferation of various cell lines, particularly those of hematopoietic origin, is also modulated by mediators of oxidative stress such as nitric oxide and thiol redox reagents. Herein we demonstrate that nitric oxide and other thiol oxidants can inhibit the autokinase activity of rat JAK2 in vitro, presumably through oxidation of crucial dithiols to disulfides within JAK2. The reduced form of JAK2 is the most active form, and the oxidized JAK2 form is inactive. Nitric oxide pretreatment of quiescent Ba/F3 cells also inhibits the interleukin 3-triggered in vivo activation of JAK2, a phenomenon that correlates with inhibited proliferation. Furthermore, we observed that the autokinase activity of JAK3 responds in a similar fashion to thiol redox reagents in vitro and to nitric oxide donors in vivo. We suggest that the thiol redox regulation of JAKs may partially explain the generally immunosuppressive effects of nitric oxide and of other thiol oxidants. PMID:9419340

  20. Biochemistry of nitric oxide and its redox-activated forms.

    PubMed

    Stamler, J S; Singel, D J; Loscalzo, J

    1992-12-18

    Nitric oxide (NO.), a potentially toxic molecule, has been implicated in a wide range of biological functions. Details of its biochemistry, however, remain poorly understood. The broader chemistry of nitrogen monoxide (NO) involves a redox array of species with distinctive properties and reactivities: NO+ (nitrosonium), NO., and NO- (nitroxyl anion). The integration of this chemistry with current perspectives of NO biology illuminates many aspects of NO biochemistry, including the enzymatic mechanism of synthesis, the mode of transport and targeting in biological systems, the means by which its toxicity is mitigated, and the function-regulating interaction with target proteins.

  1. Lipopolysaccharide induces nitric oxide synthase expression and platelet-activating factor increases nitric oxide production in human fetal membranes in culture

    PubMed Central

    Seyffarth, Gunter; Nelson, Paul N; Dunmore, Simon J; Rodrigo, Nalinda; Murphy, Damian J; Carson, Ray J

    2004-01-01

    Background Platelet-activating factor and nitric oxide may be involved in the initiation of human labour as inflammatory mediators. The aim of this study was to test whether platelet-activating factor and lipopolysaccharide were able to induce nitric oxide synthase expression and stimulate the production of nitric oxide in human fetal membrane explants in culture. Methods Fetal membranes were collected from Caesarean sections at term. RNA was extracted from membranes and subjected to a qualitative RT-PCR to assess the baseline expression of iNOS. Discs of fetal membranes were cultured for 24 hours in the presence of platelet-activating factor at a dose range of 0.1 nanomolar – 1 micomolar or 1 microgram/ml lipopolysaccharide. Nitric oxide production was measured via nitrite ions in the culture medium and mRNA for iNOS was detected by RT-PCR. Results Culturing the membrane discs in medium containing serum induced nitric oxide synthase expression and platelet-activating factor significantly stimulated the production of nitric oxide under these conditions. When cultured without serum inducible nitric oxide synthase expression was induced by lipopolysaccharide, but not by platelet-activating factor. Conclusion Platelet-activating factor may have a role in the initiation of labour, at term or preterm, via the increased local production of nitric oxide as an inflammatory mediator. In this model of intrauterine infection, lipopolysaccharide was found to induce iNOS expression by fetal membranes, and this mechanism could be involved in preterm labour. PMID:15191613

  2. Mitochondrial oxidant stress in locus coeruleus is regulated by activity and nitric oxide synthase

    PubMed Central

    Sanchez–Padilla, J.; Guzman, J.N.; Ilijic, E.; Kondapalli, J.; Galtieri, D.J.; Yang, B.; Schieber, S.; Oertel, W.; Wokosin, D.; Schumacker, P. T.; Surmeier, D. J.

    2014-01-01

    Summary Loss of noradrenergic locus coeruleus (LC) neurons is a prominent feature of aging–related neurodegenerative diseases, like Parkinson’s disease (PD). The basis of this vulnerability is not understood. To explore possible physiological determinants, LC neurons were studied using electrophysiological and optical approaches in ex vivo mouse brain slices. These studies revealed that autonomous activity in LC neurons was accompanied by oscillations in dendritic Ca2+ concentration attributable to opening of L–type Ca2+ channels. This oscillation elevated mitochondrial oxidant stress and was attenuated by inhibition of nitric oxide synthase. The relationship between activity and stress was malleable, as arousal and carbon dioxide, each increased the spike rate, but differentially affected mitochondrial oxidant stress. Oxidant stress also was increased in an animal model of PD. Thus, our results point to activity–dependent Ca2+ entry and a resulting mitochondrial oxidant stress as factors contributing to the vulnerability of LC neurons. PMID:24816140

  3. Nitric oxide directly activates calcium-dependent potassium channels in vascular smooth muscle.

    PubMed

    Bolotina, V M; Najibi, S; Palacino, J J; Pagano, P J; Cohen, R A

    1994-04-28

    Nitric oxide is the major endothelium-derived relaxing factor (EDRF), and it is thought to relax smooth muscle cells by stimulation of guanylate cyclase, accumulation of its product cyclic GMP, and cGMP-dependent modification of several intracellular processes, including activation of potassium channels through cGMP-dependent protein kinase. Here we present evidence that both exogenous nitric oxide and native EDRF can directly activate single Ca(2+)-dependent K+ channels (K+Ca) in cell-free membrane patches without requiring cGMP. Under conditions when guanylate cyclase was inhibited by methylene blue, considerable relaxation of rabbit aorta to nitric oxide persisted which was blocked by charybdotoxin, a specific inhibitor of K+Ca channels. These studies demonstrate a novel direct action of nitric oxide on K+Ca channels. PMID:7512692

  4. Nitric Oxide Measurement from Purified Enzymes and Estimation of Scavenging Activity by Gas Phase Chemiluminescence Method.

    PubMed

    Kumari, Aprajita; Gupta, Alok Kumar; Mishra, Sonal; Wany, Aakanksha; Gupta, Kapuganti Jagadis

    2016-01-01

    In plants, nitrate reductase (NR) is a key enzyme that produces nitric oxide (NO) using nitrite as a substrate. Lower plants such as algae are shown to have nitric oxide synthase enzyme and higher plants contain NOS activity but enzyme responsible for NO production in higher plants is subjected to debate. In plant nitric oxide research, it is very important to measure NO very precisely in order to determine its functional role. A significant amount of NO is being scavenged by various cell components. The net NO production depends in production minus scavenging. Here, we describe methods to measure NO from purified NR and inducible nitric oxide synthase from mouse (iNOS), we also describe a method of measure NO scavenging by tobacco cell suspensions and mitochondria from roots. PMID:27094408

  5. Effect of Zen Meditation on serum nitric oxide activity and lipid peroxidation.

    PubMed

    Kim, Do-Hoon; Moon, Yoo-Sun; Kim, Hee-Sung; Jung, Jun-Sub; Park, Hyung-Moo; Suh, Hong-Won; Kim, Yung-Hi; Song, Dong-Keun

    2005-02-01

    This study was designed to investigate the effect of Zen Meditation on serum nitric oxide activity (NO) and oxidative stress (lipid peroxidation). The experimental group included 20 subjects who had practiced the Zen Meditation program in Meditation Center located in Seoul, South Korea. The control group included 20 subjects who did not practice any formal stress management technique and were age and sex matched with experimental group. To provide an assessment of nitric oxide production, the serum level of nitrate/nitrite was determined using the Griess reagent. Malondialdehyde (MDA) concentration was measured as a convenient index of lipid peroxidation by thiobarbituric acid (TBA) method. Meditation group showed a significant higher level of serum nitrate+nitrite concentration and a significant reduced level of serum malondialdehyde (MDA) than control group. A comprehensive randomized controlled trial should be performed to prove the causal relationship between meditation and level of nitric oxide or oxidative stress in reducing cardiovascular risk factors.

  6. Effect of Nitric Oxide on the Antifungal Activity of Oxidative Stress and Azoles Against Candida albicans.

    PubMed

    Li, De-Dong; Yang, Chang-Chun; Liu, Ping; Wang, Yan; Sun, Yan

    2016-06-01

    Nitric oxide (NO) is a small molecule with a wide range of biological activities in mammalian and bacteria. However, the role of NO in fungi, especially Candida albicans, is not clear. In this study, we confirmed the generation of endogenous NO in C. albicans, and found that the production of endogenous NO in C. albicans was associated with nitric oxide synthase pathway. Our results further indicated that the production of endogenous NO in C. albicans was reduced under oxidative stress such as menadione or H2O2 treatment. Meanwhile, exogenous NO donor, sodium nitroprusside (SNP), synergized with H2O2 against C. albicans. Interestingly, SNP could inhibit the antifungal effect of azoles against C. albicans in vitro, suggesting that NO might be involved in the resistance of C. albicans to antifungals. Collectively, this study demonstrated the production of endogenous NO in C. albicans, and indicated that NO may play an important role in the response of C. albicans to oxidative stress and azoles. PMID:27570314

  7. Inhaled nitric oxide decreases pulmonary endothelial nitric oxide synthase expression and activity in normal newborn rat lungs

    PubMed Central

    Hua-Huy, Thông; Duong-Quy, Sy; Pham, Hoa; Pansiot, Julien; Mercier, Jean-Christophe; Baud, Olivier

    2016-01-01

    Inhaled nitric oxide (iNO) is commonly used in the treatment of very ill pre-term newborns. Previous studies showed that exogenous NO could affect endothelial NO synthase (eNOS) activity and expression in vascular endothelial cell cultures or adult rat models, but this has never been fully described in newborn rat lungs. We therefore aimed to assess the effects of iNO on eNOS expression and activity in newborn rats. Rat pups, post-natal day (P) 0 to P7, and their dams were placed in a chamber containing NO at 5 ppm (iNO-5 ppm group) or 20 ppm (iNO-20 ppm group), or in room air (control group). Rat pups were sacrificed at P7 and P14 for evaluation of lung eNOS expression and activity. At P7, eNOS protein expression in total lung lysates, in bronchial and arterial sections, was significantly decreased in the iNO-20 ppm versus control group. At P14, eNOS expression was comparable among all three groups. The amounts of eNOS mRNA significantly differed at P7 between the iNO-20 ppm and control groups. NOS activity decreased in the iNO-20 ppm group at P7 and returned to normal levels at P14. There was an imbalance between superoxide dismutase and NOS activities in the iNO-20 ppm group at P7. Inhalation of NO at 20 ppm early after birth decreases eNOS gene transcription, protein expression and enzyme activity. This decrease might account for the rebound phenomenon observed in patients treated with iNO.

  8. Synthesis, Nitric Oxide Release, and Anti-Leukemic Activity of Glutathione-Activated Nitric Oxide Prodrugs: Structural Analogues of PABA/NO, an Anti-Cancer Lead Compound

    PubMed Central

    Chakrapani, Harinath; Wilde, Thomas C.; Citro, Michael L.; Goodblatt, Michael M.; Keefer, Larry K.; Saavedra, Joseph E.

    2008-01-01

    Diazeniumdiolate anions and their prodrug forms are reliable sources of nitric oxide (NO) that have generated interest as promising therapeutic agents. A number of structural analogues of O2-(2,4-dinitro-5-(4-(N-methylamino)benzoyloxy)phenyl) 1-(N,N-dimethylamino)diazen-1-ium-1,2-diolate (PABA/NO), an anti-cancer lead compound that is designed to release NO upon activation by glutathione, were prepared. The nitric oxide release patterns of these O2-(2,4-dinitrophenyl) diazeniumdiolates in the presence of glutathione were tested and it was found that in the absence of competing pathways, these compounds release nearly quantitative amounts of NO. The ability of PABA/NO and its structural analogues to inhibit human leukemia cell proliferation was determined and it was found that compounds releasing elevated amounts of NO displayed superior cytotoxic effects. PMID:18060792

  9. Nitric oxide production by chicken macrophages activated by Acemannan, a complex carbohydrate extracted from Aloe vera.

    PubMed

    Karaca, K; Sharma, J M; Nordgren, R

    1995-03-01

    Cultures of normal chicken spleen cells and HD11 line cells produce nitric oxide (NO) in response to Acemannan, a complex carbohydrate derived from the Aloe vera plant. Neither cell type produced detectable amounts of NO in response to similar concentrations of yeast mannan, another complex carbohydrate. Nitric oxide production was dose dependent and inhibitable by the nitric oxide synthase inhibitor NG-methyl-L-arginine. In addition, the production of NO was inhibited by preincubation of ACM with concanavalin A in a dose-dependent manner. These results suggest that ACM-induced NO synthesis may be mediated through macrophage mannose receptors, and macrophage activation may be accountable for some of the immunomodulatory effects of ACM in chickens.

  10. Treatment of activated carbon to enhance catalytic activity for reduction of nitric oxide with ammonia

    SciTech Connect

    Ku, B.J.; Rhee, H.K. . Dept. of Chemical Engineering); Lee, J.K.; Park, D. )

    1994-11-01

    Catalytic activity of activated carbon treated with various techniques was examined in a fixed bed reactor for the reduction of nitric oxide with ammonia at 150 C. Activated carbon derived from coconut shell impregnated with an aqueous solution of ammonium sulfate, further treated with sulfuric acid, dried at 120 C, and then heated in an inert gas stream at 400 C, showed the highest catalytic activity within the range of experimental conditions. The enhancement of catalytic activity of modified activated carbon could be attributed to the increase in the amount of oxygen function groups which increased the adsorption site for ammonia. Catalytic activity of activated carbons depended on the surface area and the oxygen content as well.

  11. Staphylococcal exotoxins stimulate nitric oxide-dependent murine macrophage tumoricidal activity.

    PubMed Central

    Fast, D J; Shannon, B J; Herriott, M J; Kennedy, M J; Rummage, J A; Leu, R W

    1991-01-01

    The staphylococcal exotoxins toxic shock syndrome toxin 1 (TSST-1) and enterotoxin B were tested for their ability to stimulate murine peritoneal macrophages (PM) for tumoricidal activity. Both toxins were found to stimulate oil-elicited, gamma interferon-primed PM monolayers to kill nonadherent P815 tumor targets. The mechanism of killing of toxin-stimulated tumoricidal activity involved the production of nitric oxide, as nitrite could be demonstrated in culture fluids, and NG-monomethyl-L-arginine, an inhibitor of nitric oxide production, abrogated toxin-stimulated tumoricidal activity. TSST-1 stimulated the secretion of tumor necrosis factor by PM monolayers in the presence and absence of gamma interferon. The mechanism of toxin-stimulated tumoricidal activity was also determined to be independent of the production of reactive oxygen intermediates in that TSST-1 failed to stimulate H2O2 production by PM. These results demonstrate that the staphylococcal exotoxins are capable of stimulating macrophage production of nitric oxide for tumor cytotoxicity and suggest that the nitric oxide thus produced may subsequently play a role in the pathogenesis of the diseases caused by these toxins. PMID:1908828

  12. Extract of Meretrix meretrix Linnaeus induces angiogenesis in vitro and activates endothelial nitric oxide synthase

    NASA Astrophysics Data System (ADS)

    Liu, Ming; Wei, Jianteng; Wang, Hui; Ding, Lili; Zhang, Yuyan; Lin, Xiukun

    2012-09-01

    Meretrix meretrix Linnaeus has long been used as traditional Chinese medicine in oriental medicine. The angiogentic activity of the extract of M. meretrix was investigated in this study, using human umbilical vein endothelial cells (HUVECs). Extract of M. meretrix Linnaeus (AFG-25) was prepared with acetone and ethanol precipitation, and further separated by Sephadex G-25 column. The results show that AFG-25 promoted proliferation, migration, and capillary-like tube formation in HUVECs, and in the presence of eNOS inhibitor NMA, the tube formation induced by AFG-25 is inhibited significantly. Moreover, AFG-25 could also promote the activation of endothelial nitric oxide synthase (eNOS) and the resultant elevation of nitric oxide (NO) production. The results suggested that M. meretrix contains active ingredients with angiogentic activity and eNOS/NO signal pathway is in part involved in the proangiogenesis effect induced by AFG-25.

  13. Nitric oxide as an antioxidant

    SciTech Connect

    Kanner, J.; Harel, S.; Granit, R. )

    1991-08-15

    Benzoate monohydroxy compounds, and in particular salicylate, were produced during interaction of ferrous complexes with hydrogen peroxide (Fenton reaction) in a N2 environment. These reactions were inhibited when Fe complexes were flushed, prior to the addition in the model system, by nitric oxide. Methionine oxidation to ethylene by Fenton reagents was also inhibited by nitric oxide. Myoglobin in several forms such as metmyoglobin, oxymyoglobin, and nitric oxide-myoglobin were interacted with an equimolar concentration of hydrogen peroxide. Spectra changes in the visible region and the changes in membrane (microsomes) lipid peroxidation by the accumulation of thiobarbituric acid-reactive substances (TBA-RS) were determined. The results showed that metmyoglobin and oxymyoglobin were activated by H2O2 to ferryl myoglobin, which initiates membrane lipid peroxidation; but not nitric oxide-myoglobin, which, during interaction with H2O2, did not form ferryl but metmyoglobin which only poorly affected lipid peroxidation. It is assumed that nitric oxide, liganded to ferrous complexes, acts to prevent the prooxidative reaction of these complexes with H2O2.

  14. Influence of nitric oxide on antitumor activity of photodynamic therapy: laser systems for PDT

    NASA Astrophysics Data System (ADS)

    Evtushenko, V. A.; Zagrebelnaya, G. V.; Soldatov, Anatoly N.; Kondakova, I. V.; Shumeiko, Alexei S.

    2004-05-01

    Photodynamic therapy (PDT) is a promising therapeutic modality used for the cancer treatment. The principle of PDT is based on the formation of singlet oxygen and other activated oxygen metabolites that result in apoptotic tumor cell death. However, the resistance of some tumors to radiation therapy is recorded. The search for the chemical agents, therefore, which are able to enhance the antitumor activity of radiation therapy and induce the tumor cell apoptosis is of great importance. The use of pharmacologic agents such as donors of nitric oxide (NO) or modulators of NO-synthase may be one of the approaches to improve the therapeutic efficiency of PDT. The aim of our study was to evaluate the feasibility of using nitric oxide in combination with PDT for enhancing the induction of tumor cell apoptosis.

  15. Nitric oxide synthase expression, enzyme activity and NO production during angiogenesis in the chick chorioallantoic membrane

    PubMed Central

    Pipili-Synetos, Eva; Kritikou, Sosanna; Papadimitriou, Evangelia; Athanassiadou, Aglaia; Flordellis, C; Maragoudakis, M E

    2000-01-01

    In order to elucidate further the role of nitric oxide (NO) as an endogenous antiangiogenic mediator, mRNA expression of inducible nitric oxide synthase (iNOS), enzyme activity and production of NO were determined in the chick chorioallantoic membrane (CAM), an in vivo model of angiogenesis. In this model, maximum angiogenesis is reached between days 9–12 of chick embryo development. After that period, vascular density remains constant. Inducible NO synthase (iNOS) mRNA expression, determined by reverse transcriptase polymerase chain reaction (RT–PCR), increased from the 8th day reaching a maximum (70% increase) at days 10–11. NO synthase activity, determined as citrulline formation in the presence of calcium, also increased from day 8 reaching a maximum around day 10 (100% increase). Similar results were obtained in the absence of calcium suggesting that the NOS determined was the inducible form. Nitric oxide production, determined as nitrites, increased from day 8 reaching a maximum around day 10 (64% increase) and remaining stable at day 13. Finally, the bacterial lipopolysaccharide LPS (which activates transcriptionally iNOS), inhibited dose dependently angiogenesis in the CAM. These results in connection with previous findings from this laboratory, showing that NO inhibits angiogenesis in the CAM, suggest that increases in iNOS expression, enzyme activity and NO production closely parallel the progression of angiogenesis in the CAM, thus providing an endogenous brake to control this process. PMID:10694222

  16. Hyperhomocysteinaemia in rats is associated with erectile dysfunction by impairing endothelial nitric oxide synthase activity.

    PubMed

    Jiang, Weijun; Xiong, Lei; Bin Yang; Li, Weiwei; Zhang, Jing; Zhou, Qing; Wu, Qiuyue; Li, Tianfu; Zhang, Cui; Zhang, Mingchao; Xia, Xinyi

    2016-05-25

    To investigate the effect of hyperhomocysteinaemia (HHCy) on penile erectile function in a rat model, a methionine-rich diet was used in which erectile function, the reproductive system, and nitric oxide synthase were characterized. The intracavernous pressure, apomorphine experiments, measurement of oxidative stress, hematoxylin and eosin staining, immunohistochemistry analysis, reverse transcription-polymerase chain reactions and measurement of endothelial nitric oxide synthase activity were utilized. Our results showed that erections in the middle-dose, high-dose, and interference (INF) groups were significantly lower than the control (P < 0.05). INF group, being fed with vitamins B and folic acid, demonstrated markedly improved penile erections compared with the middle-dose group (P < 0.05). HHCy-induced eNOS and phospho-eNOS protein expression was reduced and the antioxidant effect was markedly impaired. The data of the present data provide evidence that HHCy is a vascular risk factor for erectile dysfunction by impairing cavernosa endothelial nitric oxide synthase activity. Intake of vitamins B can alleviate this abnormality.

  17. Hyperhomocysteinaemia in rats is associated with erectile dysfunction by impairing endothelial nitric oxide synthase activity

    PubMed Central

    Jiang, Weijun; Xiong, Lei; Bin Yang; Li, Weiwei; Zhang, Jing; Zhou, Qing; Wu, Qiuyue; Li, Tianfu; Zhang, Cui; Zhang, Mingchao; Xia, Xinyi

    2016-01-01

    To investigate the effect of hyperhomocysteinaemia (HHCy) on penile erectile function in a rat model, a methionine-rich diet was used in which erectile function, the reproductive system, and nitric oxide synthase were characterized. The intracavernous pressure, apomorphine experiments, measurement of oxidative stress, hematoxylin and eosin staining, immunohistochemistry analysis, reverse transcription-polymerase chain reactions and measurement of endothelial nitric oxide synthase activity were utilized. Our results showed that erections in the middle-dose, high-dose, and interference (INF) groups were significantly lower than the control (P < 0.05). INF group, being fed with vitamins B and folic acid, demonstrated markedly improved penile erections compared with the middle-dose group (P < 0.05). HHCy-induced eNOS and phospho-eNOS protein expression was reduced and the antioxidant effect was markedly impaired. The data of the present data provide evidence that HHCy is a vascular risk factor for erectile dysfunction by impairing cavernosa endothelial nitric oxide synthase activity. Intake of vitamins B can alleviate this abnormality. PMID:27221552

  18. Featured Article: Differential regulation of endothelial nitric oxide synthase phosphorylation by protease-activated receptors in adult human endothelial cells

    PubMed Central

    Tillery, Lakeisha C; Epperson, Tenille A; Eguchi, Satoru

    2016-01-01

    Protease-activated receptors have been shown to regulate endothelial nitric oxide synthase through the phosphorylation of specific sites on the enzyme. It has been established that PAR-2 activation phosphorylates eNOS-Ser-1177 and leads to the production of the potent vasodilator nitric oxide, while PAR-1 activation phosphorylates eNOS-Thr-495 and decreases nitric oxide production in human umbilical vein endothelial cells. In this study, we hypothesize a differential coupling of protease-activated receptors to the signaling pathways that regulates endothelial nitric oxide synthase and nitric oxide production in primary adult human coronary artery endothelial cells. Using Western Blot analysis, we showed that thrombin and the PAR-1 activating peptide, TFLLR, lead to the phosphorylation of eNOS-Ser-1177 in human coronary artery endothelial cells, which was blocked by SCH-79797 (SCH), a PAR-1 inhibitor. Using the nitrate/nitrite assay, we also demonstrated that the thrombin- and TFLLR-induced production of nitric oxide was inhibited by SCH and L-NAME, a NOS inhibitor. In addition, we observed that TFLLR, unlike thrombin, significantly phosphorylated eNOS-Thr-495, which may explain the observed delay in nitric oxide production in comparison to that of thrombin. Activation of PAR-2 by SLIGRL, a PAR-2 specific ligand, leads to dual phosphorylation of both catalytic sites but primarily regulated eNOS-Thr-495 phosphorylation with no change in nitric oxide production in human coronary artery endothelial cells. PAR-3, known as the non-signaling receptor, was activated by TFRGAP, a PAR-3 mimicking peptide, and significantly induced the phosphorylation of eNOS-Thr-495 with minimal phosphorylation of eNOS-Ser-1177 with no change in nitric oxide production. In addition, we confirmed that PAR-mediated eNOS-Ser-1177 phosphorylation was Ca2+-dependent using the Ca2+ chelator, BAPTA, while eNOS-Thr-495 phosphorylation was mediated via Rho kinase using the ROCK inhibitor, Y-27632

  19. Featured Article: Differential regulation of endothelial nitric oxide synthase phosphorylation by protease-activated receptors in adult human endothelial cells.

    PubMed

    Tillery, Lakeisha C; Epperson, Tenille A; Eguchi, Satoru; Motley, Evangeline D

    2016-03-01

    Protease-activated receptors have been shown to regulate endothelial nitric oxide synthase through the phosphorylation of specific sites on the enzyme. It has been established that PAR-2 activation phosphorylates eNOS-Ser-1177 and leads to the production of the potent vasodilator nitric oxide, while PAR-1 activation phosphorylates eNOS-Thr-495 and decreases nitric oxide production in human umbilical vein endothelial cells. In this study, we hypothesize a differential coupling of protease-activated receptors to the signaling pathways that regulates endothelial nitric oxide synthase and nitric oxide production in primary adult human coronary artery endothelial cells. Using Western Blot analysis, we showed that thrombin and the PAR-1 activating peptide, TFLLR, lead to the phosphorylation of eNOS-Ser-1177 in human coronary artery endothelial cells, which was blocked by SCH-79797 (SCH), a PAR-1 inhibitor. Using the nitrate/nitrite assay, we also demonstrated that the thrombin- and TFLLR-induced production of nitric oxide was inhibited by SCH and L-NAME, a NOS inhibitor. In addition, we observed that TFLLR, unlike thrombin, significantly phosphorylated eNOS-Thr-495, which may explain the observed delay in nitric oxide production in comparison to that of thrombin. Activation of PAR-2 by SLIGRL, a PAR-2 specific ligand, leads to dual phosphorylation of both catalytic sites but primarily regulated eNOS-Thr-495 phosphorylation with no change in nitric oxide production in human coronary artery endothelial cells. PAR-3, known as the non-signaling receptor, was activated by TFRGAP, a PAR-3 mimicking peptide, and significantly induced the phosphorylation of eNOS-Thr-495 with minimal phosphorylation of eNOS-Ser-1177 with no change in nitric oxide production. In addition, we confirmed that PAR-mediated eNOS-Ser-1177 phosphorylation was Ca(2+)-dependent using the Ca(2+) chelator, BAPTA, while eNOS-Thr-495 phosphorylation was mediated via Rho kinase using the ROCK inhibitor, Y-27632

  20. Nitric Oxide (NO) Generation from Heme/Copper Assembly Mediated Nitrite Reductase Activity

    PubMed Central

    Hematian, Shabnam; Siegler, Maxime A.

    2014-01-01

    Nitric oxide (NO) as a cellular signaling molecule and vasodilator regulates a range of physiological and pathological processes. Nitrite (NO2−) is recycled in vivo to generate nitric oxide, particularly in physiologic hypoxia and ischemia. The cytochrome c oxidase (CcO) binuclear hemea3/CuB active site is one entity known to be responsible for cellular nitrite conversion to nitric oxide. We recently reported that a partially reduced heme/Cu assembly reduces nitrite ion, producing NO; the heme serves as the reductant and cupric ion provides a Lewis Acid interaction with nitrite, facilitating nitrite (N−O) bond cleavage (Hematian et al., J Am Chem Soc 134:18912–18915, 2012). To further investigate this nitrite reductase (NIR) chemistry, copper(II)-nitrito complexes with tri-and tetra-dentate ligands were used in this study, where either O,O'-bidentate or O-unidentate modes of nitrite binding to the cupric center are present. To study the role of the reducing ability of the ferrous heme center, two different tetraarylporphyrinate-iron(II) complexes, one with electron donating para-methoxy peripheral substituents, (TMPP)FeII, and the other with electron withdrawing 2,6-difluorophenyl substituents, (F8)FeII, were employed. The results show that differing nitrite coordination modes to copper(II) ion leads to varying kinetic behavior. Here, also, the ferrous heme is in all cases the source of the reducing equivalent required to take nitrite to nitric oxide, but the reduction ability of the heme center does not play a key role in the observed overall reaction rate. Based on our observations, reaction mechanisms are proposed and discussed in terms of heme/Cu heterobinuclear structures. PMID:24430198

  1. NADPH-diaphorase activity and nitric oxide synthase isoforms in the trophoblast of Calomys callosus

    PubMed Central

    MORAES, NECI; ZAGO, DOUGLAS; GAGIOTI, SONIA; HOSHIDA, MARA SANDRA; BEVILACQUA, ESTELA

    2001-01-01

    The pattern of expression of a variety of placental nitric oxide synthase isoforms has contributed to elucidating the regulatory mechanisms of nitric oxide (NO) synthesis during gestation. The maintenance of vascular tone, attenuation of vasoconstriction, prevention of platelet and leukocyte adhesion to the trophoblast surface, and possible participation in uterine blood flow seem to be the main functions of NO generated at the fetal-maternal interface in humans and mice. Extending this knowledge to other rodent species commonly used as laboratory animals, in this study we focus on NADPH-diaphorase activity and the distribution of nitric oxide synthase isoforms (NOS) in the trophoblast cells of Calomys callosus during different phases of pregnancy. NADPH-diaphorase activity was evaluated cytochemically and the presence of NOS isoforms detected by immunohistochemistry. These techniques were performed on pre- and postimplantation embryos in situ and in vitro, as well as in placentae on d 14 and 18 of pregnancy. Neither NADPH-diaphorase activity nor inducible or endothelial NOS isoforms were found in pre-implanting embryos except after culturing for at least 48 h, when some of the embryonic cells were positive for the diaphorase reaction. On d 6·5 of pregnancy, trophoblast cells showed intense diaphorase activity both in situ and under in vitro conditions. A positive reaction was also found in the different placental trophoblast cells on d 14 and 18 of pregnancy. The inducible NOS (iNOS) isoform, but not the endothelial isoform, was immunodetected in trophoblast cells from the placenta and from postimplantation embryos in situ and under in vitro conditions. These results strongly suggest the production of NO by the iNOS isoform in the trophoblast of Calomys callosus after embryo implantation. The data also emphasise a possible role for the trophoblast in producing and releasing cytotoxic molecules at the fetal-maternal interface. PMID:11327206

  2. Nitric Oxide Is a Signal for NNR-Mediated Transcription Activation in Paracoccus denitrificans

    PubMed Central

    Van Spanning, Rob J. M.; Houben, Edith; Reijnders, Willem N. M.; Spiro, Stephen; Westerhoff, Hans V.; Saunders, Neil

    1999-01-01

    By using the ′lacZ gene, the activities of the nirI, nirS, and norC promoters were assayed in the wild type and in NNR-deficient mutants of Paracoccus denitrificans grown under various growth conditions. In addition, induction profiles of the three promoters in response to the presence of various nitrogenous oxides were determined. Transcription from the three promoters required the absence of oxygen and the presence both of the transcriptional activator NNR and of nitric oxide. The activity of the nnr promoter itself was halved after the cells had been switched from aerobic respiration to denitrification. This response was apparently not a result of autoregulation or of regulation by FnrP, since the nnr promoter was as active in the wild-type strain as it was in NNR- or FnrP-deficient mutants. PMID:10383987

  3. Arginase Activity in Mitochondria - an Interfering Factor in Nitric Oxide Synthase Activity Assays

    PubMed Central

    Venkatakrishnan, Priya; Nakayasu, Ernesto S.; Almeida, Igor C.; Miller, R. Timothy

    2009-01-01

    Previously, in tightly controlled studies, using three independent, yet complementary techniques, we refuted the claim that a mitochondrial nitric oxide synthase (mtNOS) isoform exists within pure, rat liver mitochondria (MT). Of those techniques, the NOS-catalyzed [14C]-L-arginine to [14C]-L-citrulline conversion assay (NOS assay) with MT samples indicated a weak, radioactive signal that was NOS-independent [1]. Aliquots of samples from the NOS assays were then extracted with acetone, separated by high performance thin-layer chromatography (HPTLC) and exposed to autoradiography. Results obtained from these samples showed no radioactive band for L-citrulline. However, a fast-migrating, diffuse, radioactive band was observed in the TLC lanes loaded with MT samples. In this manuscript, we identify and confirm that this radioactive signal in MT samples is due to the arginase-catalyzed conversion of [14C]-L-arginine to [14C]-urea. The current results, in addition to reconfirming the absence of NOS activity in rat liver MT, also show the need to include arginase inhibitors in studies using MT samples in order to avoid confounding results when using NOS activity assays. (Supported by ES 011982 & 2G12RR008124 to RTM & UTEP, respectively). PMID:19896461

  4. Arginase activity in mitochondria - An interfering factor in nitric oxide synthase activity assays

    SciTech Connect

    Venkatakrishnan, Priya; Nakayasu, Ernesto S.; Almeida, Igor C.; Miller, R.T.

    2010-04-09

    Previously, in tightly controlled studies, using three independent, yet complementary techniques, we refuted the claim that a mitochondrial nitric oxide synthase (mtNOS) isoform exists within pure, rat liver mitochondria (MT). Of those techniques, the NOS-catalyzed [{sup 14}C]-L-arginine to [{sup 14}C]-L-citrulline conversion assay (NOS assay) with MT samples indicated a weak, radioactive signal that was NOS-independent . Aliquots of samples from the NOS assays were then extracted with acetone, separated by high performance thin-layer chromatography (HPTLC) and exposed to autoradiography. Results obtained from these samples showed no radioactive band for L-citrulline. However, a fast-migrating, diffuse, radioactive band was observed in the TLC lanes loaded with MT samples. In this manuscript, we identify and confirm that this radioactive signal in MT samples is due to the arginase-catalyzed conversion of [{sup 14}C]-L-arginine to [{sup 14}C]-urea. The current results, in addition to reconfirming the absence of NOS activity in rat liver MT, also show the need to include arginase inhibitors in studies using MT samples in order to avoid confounding results when using NOS activity assays.

  5. Potentiation of osteoclast bone-resorption activity by inhibition of nitric oxide synthase.

    PubMed Central

    Kasten, T P; Collin-Osdoby, P; Patel, N; Osdoby, P; Krukowski, M; Misko, T P; Settle, S L; Currie, M G; Nickols, G A

    1994-01-01

    We have examined the effects of modulating nitric oxide (NO) levels on osteoclast-mediated bone resorption in vitro and the effects of nitric oxide synthase (NOS) inhibitors on bone mineral density in vivo. Diaphorase-based histochemical staining for NOS activity of bone sections or highly enriched osteoclast cultures suggested that osteoclasts exhibit substantial NOS activity that may account for basal NO production. Chicken osteoclasts were cultured for 36 hr on bovine bone slices in the presence or absence of the NO-generating agent sodium nitroprusside or the NOS inhibitors N-nitro-L-arginine methyl ester and aminoguanidine. Nitroprusside markedly decreased the number of bone pits and the average pit area in comparison with control cultures. On the other hand, NOS inhibition by N-nitro-L-arginine methyl ester or aminoguanidine dramatically increased the number of bone pits and the average resorption area per pit. In a model of osteoporosis, aminoguanidine potentiated the loss of bone mineral density in ovariectomized rats. Aminoguanidine also caused a loss of bone mineral density in the sham-operated rats. Inhibition of NOS activity in vitro and in vivo resulted in an apparent potentiation of osteoclast activity. These findings suggest that endogenous NO production in osteoclast cultures may regulate resorption activity. The modulation of NOS and NO levels by cells within the bone microenvironment may be a sensitive mechanism for local control of osteoclast bone resorption. Images PMID:7513424

  6. An electrogenic nitric oxide reductase.

    PubMed

    Al-Attar, Sinan; de Vries, Simon

    2015-07-22

    Nitric oxide reductases (Nors) are members of the heme-copper oxidase superfamily that reduce nitric oxide (NO) to nitrous oxide (N₂O). In contrast to the proton-pumping cytochrome oxidases, Nors studied so far have neither been implicated in proton pumping nor have they been experimentally established as electrogenic. The copper-A-dependent Nor from Bacillus azotoformans uses cytochrome c₅₅₁ as electron donor but lacks menaquinol activity, in contrast to our earlier report (Suharti et al., 2001). Employing reduced phenazine ethosulfate (PESH) as electron donor, the main NO reduction pathway catalyzed by Cu(A)Nor reconstituted in liposomes involves transmembrane cycling of the PES radical. We show that Cu(A)Nor reconstituted in liposomes generates a proton electrochemical gradient across the membrane similar in magnitude to cytochrome aa₃, highlighting that bacilli using Cu(A)Nor can exploit NO reduction for increased cellular ATP production compared to organisms using cNor. PMID:26149211

  7. Nitric oxide inhibitory activity of monogalactosylmonoacylglycerols from a freshwater microalgae Chlorella sorokiniana.

    PubMed

    Banskota, Arjun H; Stefanova, Roumiana; Gallant, Pamela; Osborne, Jane A; Melanson, Ronald; O'Leary, Stephen J B

    2013-01-01

    Chemical investigation of the freshwater microalgae Chlorella sorokiniana led to the isolation of a new monogalactosylmonoacylglycerol, namely, (2S)-1-O-(7Z,10Z-hexadecadienoyl)-3-O-β-D-galactopyranosylglycerol (1) together with a known glycolipid (2S)-1-O-(7Z,10Z,13Z-hexadecatrienoyl)-3-O-β-D-galactopyranosylglycerol (2). Both monogalactosylmonoacylglycerols showed dose-dependent nitric oxide (NO) inhibitory activity against lipopolysaccharide-induced NO production in RAW264.7 macrophage cells suggesting their possible use as anti-inflammatory agents. PMID:22703524

  8. A bioassay for brassinosteroid activity based on the in vitro fluorimetric detection of nitric oxide production.

    PubMed

    Tossi, Vanesa E; Acebedo, Sofía L; Cassia, Raúl O; Lamattina, Lorenzo; Galagovsky, Lydia R; Ramírez, Javier A

    2015-10-01

    Recent studies have shown that low concentrations of brassinolide induce a rapid generation of nitric oxide in mesophyll cells of maize leaves, which can be easily detected by fluorimetric methods. In this work we describe a series of natural and synthetic brassinosteroids that are able to trigger in vitro NO production in tomato cells that exhibits dose-response behavior. We propose that this effect can be used to develop a new rapid and very sensitive bioassay for brassinosteroid activity that offers several advantages when compared to the current methodologies.

  9. Antileishmanial Activity and Inducible Nitric Oxide Synthase Activation by RuNO Complex

    PubMed Central

    Kawakami, Natalia Yoshie; Fortes dos Santos Thomazelli, Ana Paula; Tomiotto-Pellissier, Fernanda; Kian, Danielle; Megumi Yamauchi, Lucy; Gouveia Júnior, Florêncio S.; de França Lopes, Luiz Gonzaga; Cecchini, Rubens; Nazareth Costa, Idessânia; Jerley Nogueira da Silva, Jean

    2016-01-01

    Parasites of the genus Leishmania are capable of inhibiting effector functions of macrophages. These parasites have developed the adaptive ability to escape host defenses; for example, they inactivate the NF-κB complex and suppress iNOS expression in infected macrophages, which are responsible for the production of the major antileishmanial substance nitric oxide (NO), favoring then its replication and successful infection. Metal complexes with NO have been studied as potential compounds for the treatment of certain tropical diseases, such as ruthenium compounds, known to be exogenous NO donors. In the present work, the compound cis-[Ru(bpy)2SO3(NO)]PF6, or RuNO, showed leishmanicidal activity directly and indirectly on promastigote forms of Leishmania (Leishmania) amazonensis. In addition, treatment with RuNO increased NO production by reversing the depletion of NO caused by Leishmania. We also found increased expression of Akt, iNOS, and NF-κB in infected and treated macrophages. These results demonstrated that RuNO was able to kill the parasite by NO release and modulate the transcriptional capacity of the cell. PMID:27795620

  10. Cytochrome cb-type nitric oxide reductase with cytochrome c oxidase activity from Paracoccus denitrificans ATCC 35512.

    PubMed

    Fujiwara, T; Fukumori, Y

    1996-04-01

    A highly active nitric oxide reductase was purified from Paracoccus denitrificans ATCC 35512, formerly named Thiosphaera pantotropha, which was anaerobically cultivated in the presence of nitrate. The enzyme was composed of two subunits with molecular masses of 34 and 15 kDa and contained two hemes b and one heme c per molecule. Copper was not found in the enzyme. The spectral properties suggested that one of the two hemes b and heme c were in six-coordinated low-spin states and another heme b was in a five-coordinated high-spin state and reacted with carbon monoxide. The enzyme showed high cytochrome c-nitric oxide oxidoreductase activity and formed nitrous oxide from nitric oxide with the expected stoichiometry when P. denitrificans ATCC 35512 ferrocytochrome c-550 was used as the electron donor. The V max and Km values for nitric oxide were 84 micromol of nitric oxide per min/mg of protein and 0.25 microM, respectively. Furthermore, the enzyme showed ferrocytochrome c-550-O2 oxidoreductase activity with a V max of 8.4 micromol of O2 per min/mg of protein and a Km value of 0.9 mM. Both activities were 50% inhibited by about 0.3 mM KCN. PMID:8606159

  11. Pterostilbene, an Active Constituent of Blueberries, Stimulates Nitric Oxide Production via Activation of Endothelial Nitric Oxide Synthase in Human Umbilical Vein Endothelial Cells.

    PubMed

    Park, Seong Hoon; Jeong, Sun-Oh; Chung, Hun-Teag; Pae, Hyun-Ock

    2015-09-01

    Endothelial dysfunction, a key process in development of cardiovascular diseases, is largely due to reduced nitric oxide (NO) derived from endothelial NO synthase (eNOS). Resveratrol has been reported to stimulate NO production via estrogen receptor α (ERα) activation in endothelial cells. Here, we investigated whether two natural methylated analogs of resveratrol, pterostilbene (Pts) and trans-3,5,4'-trimethoxystilbene (TMS), similarly to resveratrol, could influence endothelial NO release in human umbilical vein endothelial cells (HUVECs). In HUVECs exposed to Pts or TMS, NO production and phosphorylation of eNOS, protein kinase B (Akt), and ERα were measured by using a fluorimetric NO assay kit and Western blot analysis, respectively. Dimethylated Pts, but not trimethylated TMS, stimulated dose-dependent NO production via eNOS phosphorylation. Pts also stimulated dose-dependent phosphorylation of Akt, but not of ERα. NO production and eNOS phosphorylation in response to Pts were significantly abolished by the phosphoinositide 3-kinase (PI3K)/Akt inhibitor LY294002, but not by the ERα antagonist ICI182780. Our results suggest that Pts, but not TMS, is capable of inducing eNOS phosphorylation and the subsequent NO release, presumably, by activating PI3K/Akt pathway. The potential efficacy of Pts, an active constituent of blueberries, may aid in the prevention of cardiovascular diseases characterized by endothelial dysfunction.

  12. Evaluation of antioxidant activity and inhibitory effect on nitric oxide production of some common vegetables.

    PubMed

    Bor, Jung-Yi; Chen, Hui-Yin; Yen, Gow-Chin

    2006-03-01

    The objectives of this study were to study the antioxidant activities and nitric oxide (NO) scavenging effects of vegetables in vitro systems and to study the inhibitory effects of vegetables on the NO production and NO-induced DNA damage in RAW 264.7 macrophage. The results indicated that water extracts from Indian lotus, Jew's ear, shiitake, eggplant, and winter mushroom showed stronger antioxidant activity and free-radical-scavenging ability than that of other vegetable extracts. The scavenging effects of vegetable extracts on NO derived from sodium nitroprusside (SNP) were in decreasing order of water spinach > Indian lotus > eggplant and garland chrysanthemum. In the macrophage model system, the water extracts from fresh daylily flower, sponge gourd, pea sprout, and eggplant exhibited over 80% inhibition on NO generation stimulated by lipopolysaccharide. The extract from fresh daylily flower that expressed the strongest inhibition on NO production was attributed to the ability to reduce the inducible nitric oxide synthase (iNOS) induction. However, the extracts from pea sprout and eggplant suppressed the NO production by scavenging on NO and inactivating toward iNOS enzyme. In addition, the water extracts from fresh daylily flower, sponge gourd, pea sprout, and eggplant also showed over 40% inhibitory effect on DNA damage induced by SNP in RAW 264.7 macrophage. The data also indicated that eggplant and pea sprout extracts contained higher total phenolic compounds, anthocyanins, and ascorbic acids and appeared to be responsible for their antioxidant activities and scavenging effects on NO derived from SNP. PMID:16506819

  13. Nitric oxide synthases in pregnant rat uterus.

    PubMed

    Farina, M; Ribeiro, M L; Franchi, A

    2001-03-01

    The conversion of [14C]arginine into [14C]citrulline as an indicator of nitric oxide synthesis was studied in uteri isolated from rats on different days of gestation, after labour and during dioestrus. Nitric oxide synthesis was present in uterine tissues isolated at each stage of gestation and also in tissues collected during dioestrus and after labour. Expression of neuronal nitric oxide synthase was not detectable at any of the stages studied. Endothelial nitric oxide synthase was present at all the stages studied, but there was a significant increase on day 13 of gestation and a decrease thereafter, with the lowest expression recorded on the day after labour. Inducible nitric oxide synthase expression in rat uteri increased substantially during pregnancy, with the highest expression on day 13 of gestation; expression decreased at term and after labour. The changes in expression of inducible nitric oxide synthase were coincident with the changes in nitric oxide synthase activity in uteri treated with aminoguanidine. Thus, these findings indicate that an increase in expression of inducible nitric oxide synthase in the uterus may be important for maintenance of uterine quiescence during pregnancy and its decrease near the time of labour could have an effect on the start of uterine contractility. PMID:11226066

  14. Nitric oxide (NO) expression during annual reproductive activity in buffalo epididymis: a histochemical and immunocytochemical study.

    PubMed

    Scala, Gaetano; Maruccio, Lucianna

    2012-07-01

    The buffalo is one of the few domestic animals that has a seasonal mating cycle, influenced by the photoperiod. It is known that the photoperiod regulates gonadal function probably via the pineal and/or hypothalamus-pituitary axis. Moreover, the hypothalamus (melatonin) and gonads influence the production of the signaling transmitter nitric oxide (NO), suggesting that the NO may have an important role in the regulation of gonadotropin-releasing hormone secretion. This further suggests the hypothesis that NO in the epididymis has an important role in the maturation of spermatozoa and their motility and posterior fertilization capacity. The aim of the present study is to investigate the seasonal variations in the morphology of the epididymis by means histochemical and immunocytochemical techniques. We used the NADPH-d, nitric oxide synthase (NOS) I and NOS III to clarify the relationship between epididymis function and NO signaling activity. The results of this work show that NO is present in the caput of epididymis during short photoperiods, i.e., periods of maximum gonadal activity (winter) and absent during long photoperiods, i.e., periods of gonadal regression according to the previously described role of NO in spermatozoa capacitation and motility in the caput epididymis.

  15. [Nitric oxide production in plants].

    PubMed

    Małolepsza, Urszula

    2007-01-01

    There are still many controversial observations and opinions on the cellular/subcellular localization and sources of endogenous nitric oxide synthesis in plant cells. NO can be produced in plants by non-enzymatic and enzymatic systems depending on plant species, organ or tissue as well as on physiological state of the plant and changing environmental conditions. The best documented reactions in plant that contribute to NO production are NO production from nitrite as a substrate by cytosolic (cNR) and membrane bound (PM-NR) nitrate reductases (NR), and NO production by several arginine-dependent nitric oxide synthase-like activities (NOS). The latest papers indicate that mitochondria are an important source of arginine- and nitrite-dependent NO production in plants. There are other potential enzymatic sources of NO in plants including xanthine oxidoreductase, peroxidase, cytochrome P450. PMID:18399354

  16. Circadian variation in the effects of nitric oxide synthase inhibitors on body temperature, feeding and activity in rats.

    PubMed

    Kamerman, Peter; Mitchell, Duncan; Laburn, Helen

    2002-02-01

    We have investigated whether there is circadian variation in the effects of nitric oxide synthase inhibitors on body temperature, physical activity and feeding. We used nocturnally active Sprague-Dawley rats, housed at approximately 24 degrees C with a 12:12 h light:dark cycle (lights on 07:00 hours) and provided with food and water ad libitum. Nitric oxide synthesis was inhibited by intraperitoneal injection of the unspecific nitric oxide synthase inhibitor N-nitro- L-arginine methyl ester ( L-NAME, 100, 50, 25, 10 mg/kg), or the relatively selective inducible nitric oxide synthase inhibitor aminoguanidine (100, 50 mg/kg), during the day ( approximately 09:00 hours) or night ( approximately 21:00 hours). Body temperature and physical activity were measured using radiotelemetry, while food intake was calculated by weighing each animal's food before as well as 12 and 24 h after each injection. We found that daytime injection of L-NAME and aminoguanidine had no effect on daytime body temperature. However, daytime injection of both drugs did decrease nocturnal food intake ( P<0.05) and activity ( P<0.05). When injected at night, L-NAME reduced night-time body temperature ( P<0.01), activity ( P<0.05) and food intake ( P<0.05) in a dose-dependent manner, but night-time injection of aminoguanidine inhibited only night-time activity ( P<0.05). The effects of nitric oxide synthase inhibition on body temperature, feeding and activity therefore are primarily a consequence of inhibiting constitutively expressed nitric oxide synthase, and are subject to circadian variation.

  17. Nitric Oxide Participation in the Fungicidal Mechanism of Gamma Interferon-Activated Murine Macrophages against Paracoccidioides brasiliensis Conidia

    PubMed Central

    Gonzalez, Angel; de Gregori, Waldemar; Velez, Diana; Restrepo, Angela; Cano, Luz E.

    2000-01-01

    Paracoccidioidomycosis, a systemic mycosis restricted to Latin America and produced by the dimorphic fungus Paracoccidioides brasiliensis, is probably acquired by inhalation of conidia produced by the mycelial form. The macrophage (Mφ) represents the major cell defense against this pathogen; when activated with gamma interferon (IFN-γ), murine Mφs kill the fungus by an oxygen-independent mechanism. Our goal was to determine the role of nitric oxide in the fungicidal effect of Mφs on P. brasiliensis conidia. The results revealed that IFN-γ-activated murine Mφs inhibited the conidium-to-yeast transformation process in a dose-dependent manner; maximal inhibition was observed in Mφs activated with 50 U/ml and incubated for 96 h at 37°C. When Mφs were activated with 150 to 200 U of cytokine per ml, the number of CFU was 70% lower than in nonactivated controls, indicating that there was a fungicidal effect. The inhibitory effect was reversed by the addition of anti-IFN-γ monoclonal antibodies. Activation by IFN-γ also enhanced Mφ nitric oxide production, as revealed by increasing NO2 values (8 ± 3 μM in nonactivated Mφs versus 43 ± 13 μM in activated Mφs). The neutralization of IFN-γ also reversed nitric oxide production at basal levels (8 ± 5 μM). Additionally, we found that there was a significant inverse correlation (r = −0.8975) between NO2− concentration and transformation of P. brasiliensis conidia. Additionally, treatment with any of the three different nitric oxide inhibitors used (arginase, NG-monomethyl-l-arginine, and aminoguanidine), reverted the inhibition of the transformation process with 40 to 70% of intracellular yeast and significantly reduced nitric oxide production. These results show that IFN-γ-activated murine Mφs kill P. brasiliensis conidia through the l-arginine–nitric oxide pathway. PMID:10768942

  18. Expression of inducible nitric oxide synthase by stimulated macrophages correlates with their antihistoplasma activity.

    PubMed Central

    Lane, T E; Otero, G C; Wu-Hsieh, B A; Howard, D H

    1994-01-01

    The antihistoplasma activity of recombinant murine gamma interferon (rMuIFN-gamma)-treated macrophages of the RAW 264.7 cell line depends on the generation of nitric oxide (NO.) from L-arginine. Macrophages of the P388D1 cell line treated with rMuIFN-gamma do not produce NO. or inhibit the intracellular growth of Histoplasma capsulatum. NO. is generated by the inducible enzyme nitric oxide synthase (iNOS) formed by stimulated macrophages. Northern (RNA) blot analysis of RAW 264.7 cells revealed the expression of iNOS mRNA after exposure to rMuIFN-gamma. In contrast, rMuIFN-gamma-treated P388D1 cells did not produce detectable levels of iNOS. These data suggest that the failure of P388D1 cells to generate NO. and to restrict the intracellular growth of H. capsulatum is due to a lack of expression of iNOS following treatment with rMuIFN-gamma. Images PMID:7510670

  19. Activity and expression of nitric oxide synthase in pork skeletal muscles.

    PubMed

    Liu, Rui; Li, Yu-pin; Zhang, Wan-gang; Fu, Qing-quan; Liu, Nian; Zhou, Guang-hong

    2015-01-01

    The objective of this study was to investigate the biochemical changes of nitric oxide synthase (NOS) in pork skeletal muscles during postmortem storage. Longissimus thoracis (LT), psoas major (PM) and semimembranosus (SM) muscles of pork were removed immediately after slaughter and stored under vacuum condition at 4°C for 0, 1 and 3d. Results showed that all three muscles exhibited NOS activity until 1d while SM muscle retained NOS activity after 3d of storage. The content of nNOS in SM muscle was stable across 3d of storage while decreased intensity of nNOS was detected at 1 and 3d of aging in PM and LT muscles due to the degradation of calpain. Immunostaining showed that nNOS was located at not only sarcolemma but also cytoplasm at 0 and 1d of storage. Our data suggest that postmortem muscles possess NOS activity and nNOS expression depends on muscle type.

  20. Detection of nitric oxide pollution

    NASA Technical Reports Server (NTRS)

    Chackerian, C., Jr.; Weisbach, M. F.

    1973-01-01

    Studies of absorption spectra enhancement of certain atomic and molecular species inserter in dye-laser cavities have indicated that nitric oxide can be determined at low concentrations. Absorption coefficient of small amounts of nitric oxide in intra-laser-cavity absorption cell containing helium is enhanced by more than two orders of magnitude.

  1. Nitric oxide activation by distal redox modulation in tetranuclear iron nitrosyl complexes.

    PubMed

    de Ruiter, Graham; Thompson, Niklas B; Lionetti, Davide; Agapie, Theodor

    2015-11-11

    A series of tetranuclear iron complexes displaying a site-differentiated metal center was synthesized. Three of the metal centers are coordinated to our previously reported ligand, based on a 1,3,5-triarylbenzene motif with nitrogen and oxygen donors. The fourth (apical) iron center is coordinatively unsaturated and appended to the trinuclear core through three bridging pyrazolates and an interstitial μ4-oxide moiety. Electrochemical studies of complex [LFe3(PhPz)3OFe][OTf]2 revealed three reversible redox events assigned to the Fe(II)4/Fe(II)3Fe(III) (-1.733 V), Fe(II)3Fe(III)/Fe(II)2Fe(III)2 (-0.727 V), and Fe(II)2Fe(III)2/Fe(II)Fe(III)3 (0.018 V) redox couples. Combined Mössbauer and crystallographic studies indicate that the change in oxidation state is exclusively localized at the triiron core, without changing the oxidation state of the apical metal center. This phenomenon is assigned to differences in the coordination environment of the two metal sites and provides a strategy for storing electron and hole equivalents without affecting the oxidation state of the coordinatively unsaturated metal. The presence of a ligand-binding site allowed the effect of redox modulation on nitric oxide activation by an Fe(II) metal center to be studied. Treatment of the clusters with nitric oxide resulted in binding of NO to the apical iron center, generating a {FeNO}(7) moiety. As with the NO-free precursors, the three reversible redox events are localized at the iron centers distal from the NO ligand. Altering the redox state of the triiron core resulted in significant change in the NO stretching frequency, by as much as 100 cm(-1). The increased activation of NO is attributed to structural changes within the clusters, in particular, those related to the interaction of the metal centers with the interstitial atom. The differences in NO activation were further shown to lead to differential reactivity, with NO disproportionation and N2O formation performed by the more

  2. A connecting hinge represses the activity of endothelial nitric oxide synthase.

    PubMed

    Haque, Mohammad Mahfuzul; Panda, Koustubh; Tejero, Jesús; Aulak, Kulwant S; Fadlalla, Mohammed Adam; Mustovich, Anthony T; Stuehr, Dennis J

    2007-05-29

    In mammals, endothelial nitric oxide synthase (eNOS) has the weakest activity, being one-tenth and one-sixth as active as the inducible NOS (iNOS) and the neuronal NOS (nNOS), respectively. The basis for this weak activity is unclear. We hypothesized that a hinge element that connects the FMN module in the reductase domain but is shorter and of unique composition in eNOS may be involved. To test this hypothesis, we generated an eNOS chimera that contained the nNOS hinge and two mutants that either eliminated (P728IeNOS) or incorporated (I958PnNOS) a proline residue unique to the eNOS hinge. Incorporating the nNOS hinge into eNOS increased NO synthesis activity 4-fold, to an activity two-thirds that of nNOS. It also decreased uncoupled NADPH oxidation, increased the apparent K(m)O(2) for NO synthesis, and caused a faster heme reduction. Eliminating the hinge proline had similar, but lesser, effects. Our findings reveal that the hinge is an important regulator and show that differences in its composition restrict the activity of eNOS relative to other NOS enzymes.

  3. Steroid hormones augment nitric oxide synthase activity and expression in rat uterus.

    PubMed

    Ogando, D; Farina, M; Ribeiro, M L; Perez Martinez, S; Cella, M; Rettori, V; Franchi, A

    2003-01-01

    Nitric oxide (NO) is synthesized in a variety of tissues, including rat uterus, from L-arginine by NO synthase (NOS), of which there are three isoforms, namely neuronal, endothelial and inducible NOS (nNOS, eNOS and iNOS, respectively). Nitric oxide is an important regulator of the biology and physiology of the organs of the reproductive system, including the uterus. Some studies have shown increased variation in NO production and NOS expression during the oestrous cycle. However, the factors that regulate NO production in the uterus remain unclear. Therefore, in the present study, we investigated the effect of sex steroids on NOS expression and activity in the ovariectomized rat uterus. Ovariectomized rats received progesterone (4 mg per rat) or 17beta-oestradiol (1 microg per rat). All rats were killed 18 h after treatment. Both progesterone and oestradiol were able to augment NOS activity. The effect of oestradiol was abolished by pre-incubation with 500 micro M aminoguanidine, an iNOS inhibitor, or by coadministration of oestradiol with 3 mg kg(-1) dexamethasone, but the effect of progesterone was not affected by these treatments. Uterine nNOS, eNOS and iNOS protein levels were assessed using Western blots. Ovariectomized rat uteri expressed iNOS and eNOS. Progesterone increased the expression of eNOS and iNOS, whereas oestradiol increased iNOS expression only. These results suggest that oestradiol and progesterone are involved in the regulation of NOS expression and activity during pregnancy and implantation in the rat. PMID:14588184

  4. [The evolutionary role of nitric oxide in circadian activity and defense of the organism from cosmic rays].

    PubMed

    Iamshanov, V A

    2009-01-01

    The cosmic rays are one of the constantly acting factors influencing on genetic apparatus and depending from sun activity, which have the circadian rhythm. The nature creates a number of mechanisms, which defend the organism from cosmic rays and free radicals as consequence. However, the malfunctions of these mechanisms damage the genetic apparatus, accelerate the aging and bring to a number of illnesses. It is supposed that to neutralise the free radicals as cosmic rays consequence the organism uses its own free radicals, which have the physiological functions, for example, the nitric oxide. To limit the nitric oxide production, the mechanism of melatonin formation is used, which has a circadian rhythm.

  5. Active site cysteine-null glyceraldehyde-3-phosphate dehydrogenase (GAPDH) rescues nitric oxide-induced cell death.

    PubMed

    Kubo, Takeya; Nakajima, Hidemitsu; Nakatsuji, Masatoshi; Itakura, Masanori; Kaneshige, Akihiro; Azuma, Yasu-Taka; Inui, Takashi; Takeuchi, Tadayoshi

    2016-02-29

    Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a homotetrameric enzyme involved in a key step of glycolysis, also has a role in mediating cell death under nitrosative stress. Our previous reports suggest that nitric oxide-induced intramolecular disulfide-bonding GAPDH aggregation, which occurs through oxidation of the active site cysteine (Cys-152), participates in a mechanism to account for nitric oxide-induced death signaling in some neurodegenerative/neuropsychiatric disorders. Here, we demonstrate a rescue strategy for nitric oxide-induced cell death accompanied by GAPDH aggregation in a mutant with a substitution of Cys-152 to alanine (C152A-GAPDH). Pre-incubation of purified wild-type GAPDH with C152A-GAPDH under exposure to nitric oxide inhibited wild-type GAPDH aggregation in a concentration-dependent manner in vitro. Several lines of structural analysis revealed that C152A-GAPDH extensively interfered with nitric oxide-induced GAPDH-amyloidogenesis. Overexpression of doxycycline-inducible C152A-GAPDH in SH-SY5Y neuroblastoma significantly rescued nitric oxide-induced death, concomitant with the decreased formation of GAPDH aggregates. Further, both co-immunoprecipitation assays and simulation models revealed a heterotetramer composed of one dimer each of wild-type GAPDH and C152A-GAPDH. These results suggest that the C152A-GAPDH mutant acts as a dominant-negative molecule against GAPDH aggregation via the formation of this GAPDH heterotetramer. This study may contribute to a new therapeutic approach utilizing C152A-GAPDH against brain damage in nitrosative stress-related disorders.

  6. Jujuboside B Reduces Vascular Tension by Increasing Ca2+ Influx and Activating Endothelial Nitric Oxide Synthase

    PubMed Central

    Zhao, Yixiu; Zhang, Xin; Li, Jiannan; Bian, Yu; Sheng, Miaomiao; Liu, Bin; Fu, Zidong; Zhang, Yan; Yang, Baofeng

    2016-01-01

    Jujuboside B has been reported to have protective effect on many cardiovascular diseases. However, the effects of Jujuboside B on vascular tension and endothelial function are unknown. The present study investigated the effects of Jujuboside B on reducing vascular tension, protecting endothelial function and the potential mechanisms. The tension of isolated rat thoracic aorta ring was measured by Wire myograph system. The concentration of nitric oxide (NO) and the activity of endothelial nitric oxide synthase (eNOS) in human aortic endothelial cells (HAECs) were determined by Griess reagent method and enzyme-linked immune sorbent assay. The protein levels of eNOS and p-eNOS at Serine-1177 were determined by western blot analysis. Intracellular Ca2+ concentration in HAECs was measured by laser confocal imaging microscopy. Results showed that Jujuboside B reduced the tension of rat thoracic aorta rings with intact endothelium in a dose-dependent manner. L-NAME, KN93, EGTA, SKF96365, iberiotoxin and glibenclamide significantly attenuated Jujuboside B-induced vasodilation in endothelium-intact tissues. In contrast, indometacin and 4-DAMP had no such effects. Jujuboside B also promoted NO generation and increased eNOS activity, which were attenuated by L-NAME, EGTA and SKF96365. Moreover, Jujuboside B increased intracellular Ca2+ concentration dose-dependently, which was inhibited by EGTA and SKF96365. Besides, Jujuboside B induced a rapid Ca2+ influx instantaneously after depleting intracellular Ca2+ store, which was significantly inhibited by SKF96365. In conclusion, this study preliminarily confirmed that Jujuboside B reduced vascular tension endothelium-dependently. The underlying mechanisms involved that Jujuboside B increased extracellular Ca2+ influx through endothelial transient receptor potential cation (TRPC) channels, phosphorylated eNOS and promoted NO generation in vascular endothelial cells. In addition, Jujuboside B-induced vasodilation involved

  7. Jujuboside B Reduces Vascular Tension by Increasing Ca2+ Influx and Activating Endothelial Nitric Oxide Synthase.

    PubMed

    Zhao, Yixiu; Zhang, Xin; Li, Jiannan; Bian, Yu; Sheng, Miaomiao; Liu, Bin; Fu, Zidong; Zhang, Yan; Yang, Baofeng

    2016-01-01

    Jujuboside B has been reported to have protective effect on many cardiovascular diseases. However, the effects of Jujuboside B on vascular tension and endothelial function are unknown. The present study investigated the effects of Jujuboside B on reducing vascular tension, protecting endothelial function and the potential mechanisms. The tension of isolated rat thoracic aorta ring was measured by Wire myograph system. The concentration of nitric oxide (NO) and the activity of endothelial nitric oxide synthase (eNOS) in human aortic endothelial cells (HAECs) were determined by Griess reagent method and enzyme-linked immune sorbent assay. The protein levels of eNOS and p-eNOS at Serine-1177 were determined by western blot analysis. Intracellular Ca2+ concentration in HAECs was measured by laser confocal imaging microscopy. Results showed that Jujuboside B reduced the tension of rat thoracic aorta rings with intact endothelium in a dose-dependent manner. L-NAME, KN93, EGTA, SKF96365, iberiotoxin and glibenclamide significantly attenuated Jujuboside B-induced vasodilation in endothelium-intact tissues. In contrast, indometacin and 4-DAMP had no such effects. Jujuboside B also promoted NO generation and increased eNOS activity, which were attenuated by L-NAME, EGTA and SKF96365. Moreover, Jujuboside B increased intracellular Ca2+ concentration dose-dependently, which was inhibited by EGTA and SKF96365. Besides, Jujuboside B induced a rapid Ca2+ influx instantaneously after depleting intracellular Ca2+ store, which was significantly inhibited by SKF96365. In conclusion, this study preliminarily confirmed that Jujuboside B reduced vascular tension endothelium-dependently. The underlying mechanisms involved that Jujuboside B increased extracellular Ca2+ influx through endothelial transient receptor potential cation (TRPC) channels, phosphorylated eNOS and promoted NO generation in vascular endothelial cells. In addition, Jujuboside B-induced vasodilation involved

  8. Characterization of nitric oxide synthase activity in sheep urinary tract: functional implications.

    PubMed Central

    García-Pascual, A.; Costa, G.; Labadia, A.; Persson, K.; Triguero, D.

    1996-01-01

    1. To define further the role of nitric oxide (NO) in urinary tract function, we have measured the presence of nitric oxide synthase (NOS) activity, and its relationship with functional NO-mediated responses to electrical field stimulation (EFS) in the urethra, the detrusor and the ureter from sheep. NOS activity was assayed by the conversion of L-[14C]-arginine to L-[14C]-citrulline. Endogenous production of citrulline was confirmed by thin layer chromatography. 2. NOS enzymatic activity was detected in the cytosolic fraction from tissue homogenates with the following regional distribution (pmol citrulline mg-1 protein min-1): urethra (33 +/- 3.3), detrusor (13.1 +/- 1.1) and ureter (1.5 +/- 0.2). No activity was detected in the particulate fraction of any region. 3. NOS activity was dependent on Ca(2+)-calmodulin and required exogenously added NADPH and tetrahydrobyoptein (BH4) for maximal activity. Exclusion of calmodulin from the incubation mixture did not modify NOS activity, but it was significantly reduced in the presence of the calmodulin antagonist, calmidazolium, suggesting the presence of enough endogenous calmodulin to sustain the observed NOS activity. 4. NOS activity was inhibited to a greater extent by NG-nitro-L-arginine (L-NOARG) and its methyl ester (L-NAME) than by NG-monomethyl-L-arginine (L-NMMA), while 7-nitroindazole (7-NI) was a weak inhibitor and L-cannavine had no effect. 5. Citrulline formation could be inhibited by superoxide dismutase in an oxyhaemoglobin-sensitive manner, suggesting feedback inhibition of NOS by NO. 6. EFS induced prominent NO-mediated relaxations in the urethra while minor or no responses were observed in the detrusor and the ureter, respectively. Urethral relaxations to EFS were inhibited by NOS inhibitors with the rank order of potency: L-NOARG = L-NAME > 7-NI > L-NMMA. 7. In conclusion, we have demonstrated the presence of NO-synthesizing enzymatic activity in the sheep urinary tract which shows similar

  9. Nitric oxide and cancer

    PubMed Central

    Muntané, Jordi; la Mata, Manuel De

    2010-01-01

    Nitric oxide (NO) is a lipophilic, highly diffusible and short-lived physiological messenger which regulates a variety of important physiological responses including vasodilation, respiration, cell migration, immune response and apoptosis. NO is synthesized by three differentially gene-encoded NO synthase (NOS) in mammals: neuronal NOS (nNOS or NOS-1), inducible NOS (iNOS or NOS-2) and endothelial NOS (eNOS or NOS-3). All isoforms of NOS catalyze the reaction of L-arginine, NADPH and oxygen to NO, L-citrulline and NADP. NO may exert its cellular action by cGMP-dependent as well as by cGMP-independent pathways including postranslational modifications in cysteine (S-nitrosylation or S-nitrosation) and tyrosine (nitration) residues, mixed disulfide formation (S-nitrosoglutathione or GSNO) or promoting further oxidation protein stages which have been related to altered protein function and gene transcription, genotoxic lesions, alteration of cell-cycle check points, apoptosis and DNA repair. NO sensitizes tumor cells to chemotherapeutic compounds. The expression of NOS-2 and NOS-3 has been found to be increased in a variety of human cancers. The multiple actions of NO in the tumor environment is related to heterogeneous cell responses with particular attention in the regulation of the stress response mediated by the hypoxia inducible factor-1 and p53 generally leading to growth arrest, apoptosis or adaptation. PMID:21161018

  10. Biotransformation of nitric oxide

    SciTech Connect

    Yoshida, K.; Kasama, K.

    1987-08-01

    Previous investigations into the health effects of nitrogen oxides (NO/sub x/) have mostly been conducted with special reference to nitrogen dioxide (NO/sub 2/) and its direct effects on the respiratory system, while the study of nitric oxide (NO) has been disregarded. The authors carried out a study on NO by exposing rats and mice to /sup 15/NO or administering /sup 15/N-nitrite and /sup 15/N-nitrate to these animals by IP injection in order to elucidate the metabolic fate of NO. The results of their study and previous findings led them to assume that the major metabolic path of inhaled NO is as follows: inhaled NO reacts with hemoglobin, forming nitrosyl-hemoglobin (NOHb), and from NOHb, nitrate (NO/sub 2//sup -/ and nitrate (NO/sub 3//sup -/) are generated. Major quantities of NO/sub 3//sup -/ are discharged into the urine and a certain amount is discharged into the oral cavity through the salivary glands and transformed to NO/sub 2//sup -/. Part of this NO/sub 2//sup -/ is converted to N/sub 2/ gas in the stomach. Nitrate in the intestine is partly reduced to ammonia (NH/sub 3/) through NO/sub 2//sup -/, reabsorbed into the body, and converted to urea. Most of the metabolites of inhaled NO are excreted rapidly from the body within 48 hr.

  11. Nitric oxide releasing acetaminophen (nitroacetaminophen).

    PubMed

    Moore, P K; Marshall, M

    2003-05-01

    The nitric oxide releasing derivative of acetaminophen (nitroacetaminophen) exhibits potent anti-inflammatory and anti-nociceptive activity in a variety of animal models. On a mol for mol basis nitroacetaminophen is some 3-20 times more potent than acetaminophen. Nitroacetaminophen exhibits little or no hepatotoxicity following administration in rat or mouse and indeed protects against the hepatotoxic activity of acetaminophen. Nitroacetaminophen does not affect blood pressure or heart rate of anaesthetised rats but has similar potency to acetaminophen as an anti-pyretic agent. The enhanced anti-inflammatory and anti-nociceptive activity of nitroacetaminophen and the reduced hepatotoxicity in these animal models is likely to be secondary to the slow release of nitric oxide from the molecule. As yet the precise molecular mechanism(s) underlying these actions of nitroacetaminophen are not clear. Evidence for inhibition of cytokine-directed formation of pro-inflammatory molecule production (e.g. COX-2, iNOS) by an effect on the NF-kappaB transduction system and/or nitrosylation (and thence inhibition) of caspase enzyme activity has been reported. Data described in this review indicate that the profile of pharmacological activity of nitroacetaminophen and acetaminophen are markedly different. The possibility that nitroacetaminophen could be an attractive alternative to acetaminophen in the clinic is discussed. PMID:12846444

  12. [Physical activity and endothelial dysfunction in type 2 diabetic patients: the role of nitric oxide and oxidative stress].

    PubMed

    Brinkmann, Christian; Schwinger, Robert H G; Brixius, Klara

    2011-06-01

    Type 2 diabetic patients have an increased level of systemic free radicals, which severely restrict the bioavailability of endothelium-derived nitric oxide (NO) and thus contribute to the development of an endothelial dysfunction. This review analyses the influence of physical training on molecular development mechanisms of the endothelial dysfunction and determines the significance of regular physical exercise for the endothelial function in type 2 diabetic patients. Systematic training reinforces the endogenic antioxidative capacity and results in a reduction in oxidative stress. Training - also combined with a change in diet - furthermore reduces hyperglycaemic blood sugar levels, thus curbing a major source of free radicals in diabetes. Moreover, physical exercise enhances vascular NO synthesis through an increased availability/activity of endothelial NO synthases (eNOS). Endurance, as well as resistance training with submaximal intensity or a combination of both forms of training is suitable to effectively improve the endothelial function in type 2 diabetic patients in the long term. PMID:21360292

  13. Signalling pathway involved in nitric oxide synthase type II activation in chondrocytes: synergistic effect of leptin with interleukin-1

    PubMed Central

    Otero, Miguel; Lago, Rocío; Lago, Francisca; Reino, Juan Jesús Gomez; Gualillo, Oreste

    2005-01-01

    The objective of the present study was to investigate the effect of leptin, alone or in combination with IL-1, on nitric oxide synthase (NOS) type II activity in vitro in human primary chondrocytes, in the mouse chondrogenic ATDC5 cell line, and in mature and hypertrophic ATDC5 differentiated chondrocytes. For completeness, we also investigated the signalling pathway of the putative synergism between leptin and IL-1. For this purpose, nitric oxide production was evaluated using the Griess colorimetric reaction in culture medium of cells stimulated over 48 hours with leptin (800 nmol/l) and IL-1 (0.025 ng/ml), alone or combined. Specific pharmacological inhibitors of NOS type II (aminoguanidine [1 mmol/l]), janus kinase (JAK)2 (tyrphostin AG490 and Tkip), phosphatidylinositol 3-kinase (PI3K; wortmannin [1, 2.5, 5 and 10 μmol/l] and LY294002 [1, 2.5, 5 and 10 μmol/l]), mitogen-activated protein kinase kinase (MEK)1 (PD098059 [1, 5, 10, 20 and 30 μmol/l]) and p38 kinase (SB203580 [1, 5, 10, 20 and 30 μmol/l]) were added 1 hour before stimulation. Nitric oxide synthase type II mRNA expression in ATDC5 chondrocytes was investigated by real-time PCR and NOS II protein expression was analyzed by western blot. Our results indicate that stimulation of chondrocytes with IL-1 results in dose-dependent nitric oxide production. In contrast, leptin alone was unable to induce nitric oxide production or expression of NOS type II mRNA or its protein. However, co-stimulation with leptin and IL-1 resulted in a net increase in nitric oxide concentration over IL-1 challenge that was eliminated by pretreatment with the NOS II specific inhibitor aminoguanidine. Pretreatment with tyrphostin AG490 and Tkip (a SOCS-1 mimetic peptide that inhibits JAK2) blocked nitric oxide production induced by leptin/IL-1. Finally, wortmannin, LY294002, PD098059 and SB203580 significantly decreased nitric oxide production. These findings were confirmed in mature and hypertrophic ATDC5 chondrocytes, and

  14. Nitric oxide fumigation stimulates flavonoid and phenolic accumulation and enhances antioxidant activity of mushroom.

    PubMed

    Dong, Jufang; Zhang, Ming; Lu, Li; Sun, Lina; Xu, Maojun

    2012-12-01

    The effects of nitric oxide (NO) on antioxidant activity and contents of phenolics and flavonoids in mushroom Russula griseocarnosa were investigated. Freshly harvested mushrooms were fumigated with 0, 10, 20 and 30μLL(-1) NO at 20°C for 2h and then taken to examine the antioxidant activities using assays of reducing power, chelating effect on ferrous ions, scavenging effect on hydroxyl free radicals, and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. The results showed that the antioxidant activities of the mushrooms fumigated with NO were significantly increased when compared to the controls. Moreover, NO fumigation significantly enhanced phenolic and flavonoid contents and stimulated the activities of phenylalanine ammonia-lyase and chalcone synthase. The results indicated that NO fumigation might have potential application for enhancing the bioactive compounds and improving antioxidant activities in the mushrooms. Furthermore, the data suggested that the NO-induced phenolic and flavonoid accumulation was due to the activation of the biosynthetic pathways in the mushrooms.

  15. Cytotoxic and Nitric Oxide Inhibition Activities of Propolis Extract along with Microencapsulation by Complex Coacervation.

    PubMed

    Onbas, Rabia; Kazan, Aslihan; Nalbantsoy, Ayse; Yesil-Celiktas, Ozlem

    2016-09-01

    In this study, cytotoxicity of ethanol extract of propolis (EEP) originating from Sivas, Turkey was screened against several cancer cell lines, namely PC-3, U87MG, A-549, mPANC96, CaCo-2, MCF-7, HeLa, MDA-MB-231 and a non-tumor cell line HEK293 by MTT assay. The inhibition levels of inducible nitric oxide synthase (iNOS) were also determined by using RAW 264.7 macrophage cells following lipopolysaccharide (LPS) treatment. EEP exhibited significant cytotoxic nitric oxide inhibition activities with an IC50 value of 0.1 ± 0.1 μg/ml indicating a high potential as an anti-inflammatory agent. In spite of these promising results and the fact that propolis is a highly nutritive substance, its low solubility and bitter taste limit the applications as a natural supplement. Encapsulation might serve as a good strategy in order to overcome these problems. Complex coacervation was applied where the main focus was on surfactant type, polymer ratio (alginate:gelatin), stirring rate and concentration of core material. The mean particle size of unloaded microparticles were 22.62 μm obtained with gelatin:alginate ratio of 1:1 at a stirring rate of 1400 rpm with 2 ml of 1 % (w/v) sodium carboxymethyl cellulose (Na-CMC), whereas addition of EEP at a concentration of 100 mg/ml increased the mean particle size to 36.44 μm and yielded an encapsulation efficiency of 98.77 %. The cytotoxicities of EEP loaded microparticles were also assessed both on MCF-7 and MDA-MB-231 where similar results were achieved as free EEP which can enhance the possible use of propolis extract in the industry as a natural supplement. PMID:27380456

  16. 49 CFR 173.337 - Nitric oxide.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Nitric oxide. 173.337 Section 173.337... SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.337 Nitric oxide. (a) Nitric oxide must be... valve and valve seat that will not deteriorate in contact with nitric oxide. Cylinders or valves may...

  17. Enhancing effect of oxygen radical scavengers on murine macrophage anticryptococcal activity through production of nitric oxide

    PubMed Central

    TOHYAMA, M.; KAWAKAMI, K.; FUTENMA, M.; SAITO, A.

    1996-01-01

    We examined the roles of reactive nitrogen intermediates (RNI) and reactive oxygen intermediates (ROI) in interferon-gamma (IFN-γ)-induced cryptococcostatic activity of murine peritoneal macrophages using NG-monomethyl-L-arginine (L-NMMA), a competitive inhibitor of RNI synthesis, and superoxide dismutase (SOD) and catalase, oxygen radical scavengers. IFN-γ-activated macrophages produced nitric oxide (NO) in a dose-dependent manner, as measured by increased nitrite concentration in the culture supernatant. IFN-γ also enhanced the suppressive effect on cryptococcal growth in a similar dose-dependent manner. The induction of killing activity and NO production by an optimal dose of IFN-γ (100 U/ml) was virtually suppressed by 500 μM L-NMMA. These results confirmed the importance of the RNI-mediated effector mechanism in anticryptococcal activity of macrophages. SOD and catalase significantly enhanced the cryptococcostatic activity of macrophages induced by a suboptimal dose of IFN-γ (20 U/ml). The augmenting effect of these reagents was mediated by NO, since they potentiated the production of NO by macrophages and their effects were totally blocked by L-NMMA. Our results indicate that the IFN-γ-induced anticryptococcal activity of macrophages is dependent mostly on RNI, and suggest that the ROI system down-regulates the effector mechanism for cryptococcostasis by suppressing the RNI system. PMID:8608643

  18. Long-term aerobic exercise increases redox-active iron through nitric oxide in rat hippocampus.

    PubMed

    Chen, Qian; Xiao, De-Sheng

    2014-01-30

    Adult hippocampus is highly vulnerable to iron-induced oxidative stress. Aerobic exercise has been proposed to reduce oxidative stress but the findings in the hippocampus are conflicting. This study aimed to observe the changes of redox-active iron and concomitant regulation of cellular iron homeostasis in the hippocampus by aerobic exercise, and possible regulatory effect of nitric oxide (NO). A randomized controlled study was designed in the rats with swimming exercise treatment (for 3 months) and/or an unselective inhibitor of NO synthase (NOS) (L-NAME) treatment. The results from the bleomycin-detectable iron assay showed additional redox-active iron in the hippocampus by exercise treatment. The results from nonheme iron content assay, combined with the redox-active iron content, showed increased storage iron content by exercise treatment. NOx (nitrate plus nitrite) assay showed increased NOx content by exercise treatment. The results from the Western blot assay showed decreased ferroportin expression, no changes of TfR1 and DMT1 expressions, increased IRP1 and IRP2 expression, increased expressions of eNOS and nNOS rather than iNOS. In these effects of exercise treatment, the increased redox-active iron content, storage iron content, IRP1 and IRP2 expressions were completely reversed by L-NAME treatment, and decreased ferroportin expression was in part reversed by L-NAME. L-NAME treatment completely inhibited increased NOx and both eNOS and nNOS expression in the hippocampus. Our findings suggest that aerobic exercise could increase the redox-active iron in the hippocampus, indicating an increase in the capacity to generate hydroxyl radicals through the Fenton reactions, and aerobic exercise-induced iron accumulation in the hippocampus might mainly result from the role of the endogenous NO.

  19. [Does nitric oxide stress exist?].

    PubMed

    Torreilles, J; Guérin, M C

    1995-01-01

    Ten years ago, the term "oxidative stress" (sigma -O2) was created to define oxidative damage inflicted to the organism. This definition brings together processes involving reactive oxygen species production and action such as free radical production during univalent reduction of oxygen within mitochondria, activation of NADPH-dependent oxidase system on the membrane surface of neutrophils, flavoprotein-catalyzed redox cycling of xenobiotics and exposure to chemical and physical agents in the environment. Since the discovery of the nitric oxide biosynthetic pathway, the deleterious effects of uncontrolled nitric oxide generation are generally classified as oxidative stress. Indeed, products of the reaction of NO and superoxide lead to oxidants such as peroxinitrite, nitrogen dioxide and hydroxyl radical, which are involved in mechanisms of cell-mediated immune reactions and defence of the intracellular environment against microbiol invasion. However NO can also regulate many biological reactions and signal transduction pathways that lead to a variety of physiological responses such as blood pressure, neurotransmission, platelet aggregation, endothelin generation or smooth muscle cell proliferation. Then the uncontrolled NO production can lead to a variety of physiological and pathophysiological responses similar to a Nitric Oxide Stress: activation of guanylate cyclase and production of cGMP: overstimulation of the inducible L-arginine to L-citrulline and NO pathway by bactericidal endotoxins and cytokines has been shown to promote undesired increases in vasodilatation, which may account for hypotension in septic shock and cytokine therapy. stimulation of auto-ADP-ribosylation and modification of SH-groups of glyceraldehyde-3-phosphate dehydrogenase in a cGMP-independent mechanism: by this way, NO in excess can strongly inhibits this important glycolytic enzyme and reduce the cellular energy production. inhibition of ribonucleotide reductase: extensive inhibition

  20. Spectroscopic measurement of cortical nitric oxide release induced by ascending activation.

    PubMed

    Espinosa, N; Cudeiro, J; Mariño, J

    2015-01-29

    The transition from sleep to the awake state is regulated by the activation of subcortical nuclei of the brainstem (BS) and basal forebrain (BF), releasing acetylcholine and glutamate throughout the cortex and inducing a tonic state of neural activity. It has been suggested that such activation is also mediated by the massive and diffuse cortical release of nitric oxide (NO). In this work we have combined the spectroscopic measurement of NO levels in the somatosensory cortex of the cat through its marker methemoglobin, as well as two other hemodynamic markers (oxyhemoglobin--oxyHb--and deoxyhemoglobin--deoxyHb), together with the electrical stimulation of BS and BF--to induce an experimental transition from a sleep-like state to an awake-like mode. The results show an increase of NO levels either after BS or BF activation. The response induced by BS stimulation was biphasic in the three studied markers, and lasted for up to 30s. The changes induced by BF were monophasic lasting for up to 20s. The systemic blockade of NO production abolished the observed responses to BS whereas responses to BF stimulation were much less affected. These results indicate a crucial role for NO in the neuronal activation induced by the ascending systems. PMID:25463513

  1. Antioxidant and nitric oxide production inhibitory activities of galacturonyl hydroxamic acid.

    PubMed

    Liu, Yuh-Hwa; Lin, Shyr-Yi; Lee, Chi-Ching; Hou, Wen-Chi

    2008-07-01

    The self-prepared pectin hydroxamic acid has been reported to have antioxidant activities [Yang, S. S., Cheng, K. D., Lin, Y. S., Liu, Y. W., & Hou, W. C. (2004). Pectin hydroxamic acids exhibit antioxidant activities in vitro. Journal of Agricultural and Food Chemistry, 52, 4270-4273]. In this study, the galacturonic acid (GalA), the monomer unit of the pectin polymer, was esterified with acidic methanol (1N HCl) at 4°C with gentle stirring for 5days to get galacturonic acid methyl ester which was further reacted with alkaline hydroxylamine to get galacturonyl hydroxamic acid (GalA-NHOH). The GalA-NHOH was used to test the antioxidant and antiradical activities in the comparison with GalA. The scavenging activities of GalA-NHOH against DPPH radicals (half-inhibition concentration, IC50, was 82μM), hydroxyl radicals detected by electron spin resonance (IC50 was 0.227nM in the comparison with Trolox of 0.433μM), superoxide radicals (IC50 was 830μM) were determined. The protection activities of GalA-NHOH against hydroxyl radicals-mediated calf thymus DNA damages, linoleic acid peroxidation and peroxynitrite-mediated dihydrorhodamine 123 oxidations were also investigated. It was found that the GalA-NHOH exhibited dose-dependently antioxidant activity and few or none was found in GalA. The GalA-NHOH was used to evaluate the suppressed activity of nitric oxide (NO) productions of RAW264.7 cells in the presence of lipopolysaccharide (LPS, 100ng/ml) as inducers. It was found that GalA-NHOH (0.02-0.1mg/ml) could dose-dependently suppress the NO productions (expressed as nitrite concentrations) in RAW264.7 cells without significant cytotoxicity.

  2. Nitric Oxide Homeostasis in Neurodegenerative Diseases.

    PubMed

    Hannibal, Luciana

    2016-01-01

    The role of nitric oxide in the pathogenesis and progression of neurodegenerative illnesses such as Parkinson's and Alzheimer's diseases has become prominent over the years. Increased activity of the enzymes that produce reactive oxygen species, decreased activity of antioxidant enzymes and imbalances in glutathione pools mediate and mark the neurodegenerative process. Much of the oxidative damage of proteins is brought about by the overproduction of nitric oxide by nitric oxide synthases (NOS) and its subsequent reactivity with reactive oxygen species. Proteomic methods have advanced the field tremendously, by facilitating the quantitative assessment of differential expression patterns and oxidative modifications of proteins and alongside, mapping their non-canonical functions. As a signaling molecule involved in multiple biochemical pathways, the level of nitric oxide is subject to tight regulation. All three NOS isoforms display aberrant patterns of expression in Alzheimer's disease, altering intracellular signaling and routing oxidative stress in directions that are uncompounded. This review discusses the prime factors that control nitric oxide biosynthesis, reactivity footprints and ensuing effects in the development of neurodegenerative diseases.

  3. Nitric oxide and nitric oxide synthase in Huntington's disease.

    PubMed

    Deckel, A W

    2001-04-15

    Nitric oxide (NO) is a biologically active inorganic molecule produced when the semiessential amino acid l-arginine is converted to l-citrulline and NO via the enzyme nitric oxide synthase (NOS). NO is known to be involved in the regulation of many physiological processes, such as control of blood flow, platelet adhesion, endocrine function, neurotransmission, neuromodulation, and inflammation, to name only a few. During neuropathological conditions, the production of NO can be either protective or toxic, dependent on the stage of the disease, the isoforms of NOS involved, and the initial pathological event. This paper reviews the properties of NO and NOS and the pathophysiology of Huntington's disease (HD). It discusses ways in which NO and NOS may interact with the protein product of HD and reviews data implicating NOS in the neuropathology of HD. This is followed by a synthesis of current information regarding how NO/NOS may contribute to HD-related pathology and identification of areas for potential future research. PMID:11288139

  4. Nitric oxide and nitric oxide synthase in Huntington's disease.

    PubMed

    Deckel, A W

    2001-04-15

    Nitric oxide (NO) is a biologically active inorganic molecule produced when the semiessential amino acid l-arginine is converted to l-citrulline and NO via the enzyme nitric oxide synthase (NOS). NO is known to be involved in the regulation of many physiological processes, such as control of blood flow, platelet adhesion, endocrine function, neurotransmission, neuromodulation, and inflammation, to name only a few. During neuropathological conditions, the production of NO can be either protective or toxic, dependent on the stage of the disease, the isoforms of NOS involved, and the initial pathological event. This paper reviews the properties of NO and NOS and the pathophysiology of Huntington's disease (HD). It discusses ways in which NO and NOS may interact with the protein product of HD and reviews data implicating NOS in the neuropathology of HD. This is followed by a synthesis of current information regarding how NO/NOS may contribute to HD-related pathology and identification of areas for potential future research.

  5. Activation of Endothelial Nitric Oxide (eNOS) Occurs through Different Membrane Domains in Endothelial Cells.

    PubMed

    Tran, Jason; Magenau, Astrid; Rodriguez, Macarena; Rentero, Carles; Royo, Teresa; Enrich, Carlos; Thomas, Shane R; Grewal, Thomas; Gaus, Katharina

    2016-01-01

    Endothelial cells respond to a large range of stimuli including circulating lipoproteins, growth factors and changes in haemodynamic mechanical forces to regulate the activity of endothelial nitric oxide synthase (eNOS) and maintain blood pressure. While many signalling pathways have been mapped, the identities of membrane domains through which these signals are transmitted are less well characterized. Here, we manipulated bovine aortic endothelial cells (BAEC) with cholesterol and the oxysterol 7-ketocholesterol (7KC). Using a range of microscopy techniques including confocal, 2-photon, super-resolution and electron microscopy, we found that sterol enrichment had differential effects on eNOS and caveolin-1 (Cav1) colocalisation, membrane order of the plasma membrane, caveolae numbers and Cav1 clustering. We found a correlation between cholesterol-induced condensation of the plasma membrane and enhanced high density lipoprotein (HDL)-induced eNOS activity and phosphorylation suggesting that cholesterol domains, but not individual caveolae, mediate HDL stimulation of eNOS. Vascular endothelial growth factor (VEGF)-induced and shear stress-induced eNOS activity was relatively independent of membrane order and may be predominantly controlled by the number of caveolae on the cell surface. Taken together, our data suggest that signals that activate and phosphorylate eNOS are transmitted through distinct membrane domains in endothelial cells.

  6. Activation of Endothelial Nitric Oxide (eNOS) Occurs through Different Membrane Domains in Endothelial Cells.

    PubMed

    Tran, Jason; Magenau, Astrid; Rodriguez, Macarena; Rentero, Carles; Royo, Teresa; Enrich, Carlos; Thomas, Shane R; Grewal, Thomas; Gaus, Katharina

    2016-01-01

    Endothelial cells respond to a large range of stimuli including circulating lipoproteins, growth factors and changes in haemodynamic mechanical forces to regulate the activity of endothelial nitric oxide synthase (eNOS) and maintain blood pressure. While many signalling pathways have been mapped, the identities of membrane domains through which these signals are transmitted are less well characterized. Here, we manipulated bovine aortic endothelial cells (BAEC) with cholesterol and the oxysterol 7-ketocholesterol (7KC). Using a range of microscopy techniques including confocal, 2-photon, super-resolution and electron microscopy, we found that sterol enrichment had differential effects on eNOS and caveolin-1 (Cav1) colocalisation, membrane order of the plasma membrane, caveolae numbers and Cav1 clustering. We found a correlation between cholesterol-induced condensation of the plasma membrane and enhanced high density lipoprotein (HDL)-induced eNOS activity and phosphorylation suggesting that cholesterol domains, but not individual caveolae, mediate HDL stimulation of eNOS. Vascular endothelial growth factor (VEGF)-induced and shear stress-induced eNOS activity was relatively independent of membrane order and may be predominantly controlled by the number of caveolae on the cell surface. Taken together, our data suggest that signals that activate and phosphorylate eNOS are transmitted through distinct membrane domains in endothelial cells. PMID:26977592

  7. Macrophage activation: role of toll-like receptors, nitric oxide, and nuclear factor kappa B.

    PubMed

    Billack, Blase

    2006-10-15

    Macrophages play an important role in host-defense and inflammation. In response to an immune challenge, macrophages become activated and produce proinflammatory mediators that contribute to nonspecific immunity. The mediators released by activated macrophages include: superoxide anion; reactive nitrogen intermediates, such as nitric oxide and peroxynitrite; bioactive lipids; and cytokines. Although essential to the immune response, overproduction of certain macrophage-derived mediators during an immune challenge or inflammatory response can result in tissue injury and cellular death. The present report is focused on understanding some of the molecular mechanisms used by macrophages to produce reactive nitrogen intermediates in response to immunostimulatory agents such as heat shock protein 60 and bacterial lipopolysaccharide. The role of Toll-like receptors and transcription factors such as nuclear factor kappa B (NFkappaB) in the innate immune response is also described. A basic understanding of the underlying molecular mechanisms responsible for macrophage activation should serve as a foundation for novel drug development aimed at modulating macrophage activity.

  8. Mechanical perturbations trigger endothelial nitric oxide synthase activity in human red blood cells

    PubMed Central

    Nagarajan, Shunmugan; Raj, Rajendran Kadarkarai; Saravanakumar, Venkatesan; Balaguru, Uma Maheswari; Behera, Jyotirmaya; Rajendran, Vinoth Kumar; Shathya, Yogarajan; Ali, B. Mohammed Jaffar; Sumantran, Venil; Chatterjee, Suvro

    2016-01-01

    Nitric oxide (NO), a vascular signaling molecule, is primarily produced by endothelial NO synthase. Recently, a functional endothelial NO synthase (eNOS) was described in red blood cells (RBC). The RBC-eNOS contributes to the intravascular NO pool and regulates physiological functions. However the regulatory mechanisms and clinical implications of RBC-eNOS are unknown. The present study investigated regulation and functions of RBC-eNOS under mechanical stimulation. This study shows that mechanical stimuli perturb RBC membrane, which triggers a signaling cascade to activate the eNOS. Extracellular NO level, estimated by the 4-Amino-5-Methylamino-2′, 7′-Difluorofluorescein Diacetate probe, was significantly increased under mechanical stimuli. Immunostaining and western blot studies confirmed that the mechanical stimuli phosphorylate the serine 1177 moiety of RBC-eNOS, and activates the enzyme. The NO produced by activation of RBC-eNOS in vortexed RBCs promoted important endothelial functions such as migration and vascular sprouting. We also show that mechanical perturbation facilitates nitrosylation of RBC proteins via eNOS activation. The results of the study confirm that mechanical perturbations sensitize RBC-eNOS to produce NO, which ultimately defines physiological boundaries of RBC structure and functions. Therefore, we propose that mild physical perturbations before, after, or during storage can improve viability of RBCs in blood banks. PMID:27345770

  9. Naphthoquinones and Bioactive Compounds from Tobacco as Modulators of Neuronal Nitric Oxide Synthase Activity

    PubMed Central

    Venkatakrishnan, Priya; Gairola, C. Gary; Castagnoli, Neal; Miller, R. Timothy

    2009-01-01

    Studies were conducted with extracts of several varieties of tobacco in search of neuronal nitric oxide synthase (nNOS) inhibitors which may be of value in the treatment of stroke. Current therapies do not directly exploit modulation of nNOS activity due to poor selectivity of the currently available nNOS inhibitors. The properties of a potentially novel nNOS inhibitor(s) derived from tobacco extracts, and the concentration-dependent, modulatory effects of the tobacco-derived naphthoquinone compound, 2, 3, 6-trimethyl-1, 4-naphthoquinone (TMN), on nNOS activity were investigated, using 2-methyl-1, 4-naphthoquinone (menadione) as a control. Up to 31μM, both TMN and menadione stimulated nNOS-catalyzed L-citrulline production. However, at higher concentrations of TMN (62.5-500 μM), the stimulation was lost in a concentration-dependent manner. With TMN, the loss of stimulation did not decrease beyond the control activity. With menadione (62.5-500 μM), the loss of stimulation surpassed that of the control (78 ± 0.01%), indicating a complete inhibition of nNOS activity. This study suggests that potential nNOS inhibitors are present in tobacco, most of which remain to be identified. PMID:19367663

  10. Active chlorine and nitric oxide formation from chemical rocket plume afterburning

    NASA Astrophysics Data System (ADS)

    Leone, D. M.; Turns, S. R.

    Chlorine and oxides of nitrogen (NO(x)) released into the atmosphere contribute to acid rain (ground level or low-altitude sources) and ozone depletion from the stratosphere (high-altitude sources). Rocket engines have the potential for forming or activating these pollutants in the rocket plume. For instance, H2/O2 rockets can produce thermal NO(x) in their plumes. Emphasis, in the past, has been placed on determining the impact of chlorine release on the stratosphere. To date, very little, if any, information is available to understand what contribution NO(x) emissions from ground-based engine testing and actual rocket launches have on the atmosphere. The goal of this work is to estimate the afterburning emissions from chemical rocket plumes and determine their local stratospheric impact. Our study focuses on the space shuttle rocket motors, which include both the solid rocket boosters (SRB's) and the liquid propellant main engines (SSME's). Rocket plume afterburning is modeled employing a one-dimensional model incorporating two chemical kinetic systems: chemical and thermal equilibria with overlayed nitric oxide chemical kinetics (semi equilibrium) and full finite-rate chemical kinetics. Additionally, the local atmospheric impact immediately following a launch is modeled as the emissions diffuse and chemically react in the stratosphere.

  11. Active chlorine and nitric oxide formation from chemical rocket plume afterburning

    NASA Technical Reports Server (NTRS)

    Leone, D. M.; Turns, S. R.

    1994-01-01

    Chlorine and oxides of nitrogen (NO(x)) released into the atmosphere contribute to acid rain (ground level or low-altitude sources) and ozone depletion from the stratosphere (high-altitude sources). Rocket engines have the potential for forming or activating these pollutants in the rocket plume. For instance, H2/O2 rockets can produce thermal NO(x) in their plumes. Emphasis, in the past, has been placed on determining the impact of chlorine release on the stratosphere. To date, very little, if any, information is available to understand what contribution NO(x) emissions from ground-based engine testing and actual rocket launches have on the atmosphere. The goal of this work is to estimate the afterburning emissions from chemical rocket plumes and determine their local stratospheric impact. Our study focuses on the space shuttle rocket motors, which include both the solid rocket boosters (SRB's) and the liquid propellant main engines (SSME's). Rocket plume afterburning is modeled employing a one-dimensional model incorporating two chemical kinetic systems: chemical and thermal equilibria with overlayed nitric oxide chemical kinetics (semi equilibrium) and full finite-rate chemical kinetics. Additionally, the local atmospheric impact immediately following a launch is modeled as the emissions diffuse and chemically react in the stratosphere.

  12. Inhibition of Inducible Nitric Oxide Synthase Expression by a Novel Small Molecule Activator of the Unfolded Protein Response

    PubMed Central

    Symons, Kent T; Massari, Mark E; Dozier, Sara J; Nguyen, Phan M; Jenkins, David; Herbert, Mark; Gahman, Timothy C; Noble, Stewart A; Rozenkrants, Natasha; Zhang, Yan; Rao, Tadimeti S; Shiau, Andrew K; Hassig, Christian A

    2008-01-01

    The transcription of inducible nitric oxide synthase (iNOS) is activated by a network of proinflammatory signaling pathways. Here we describe the identification of a small molecule that downregulates the expression of iNOS mRNA and protein in cytokine-activated cells and suppresses nitric oxide production in vivo. Mechanistic analysis suggests that this small molecule, erstressin, also activates the unfolded protein response (UPR), a signaling pathway triggered by endoplasmic reticulum stress. Erstressin induces rapid phosphorylation of eIF2α and the alternative splicing of XBP-1, hallmark initiating events of the UPR. Further, erstressin activates the transcription of multiple genes involved in the UPR. These data suggest an inverse relationship between UPR activation and iNOS mRNA and protein expression under proinflammatory conditions. PMID:20161838

  13. Endogenous nitric oxide accumulation is involved in the antifungal activity of Shikonin against Candida albicans

    PubMed Central

    Liao, Zebin; Yan, Yu; Dong, Huaihuai; Zhu, Zhenyu; Jiang, Yuanying; Cao, Yingying

    2016-01-01

    The aim of the present study was to investigate the role of nitric oxide (NO) in the antifungal activity of Shikonin (SK) against Candida albicans (C. albicans) and to clarify the underlying mechanism. The results showed that the NO donors S-nitrosoglutathione (GSNO) and L-arginine could enhance the antifungal activity of SK, whereas the NO production inhibitor Nω-nitro-L-arginine methyl ester (L-NAME) attenuated antifungal action. Using the fluorescent dye 3-amino,4-aminomethyl-2′, 7-difluorescein, diacetate (DAF-FM DA), we found that the accumulation of NO in C. albicans was increased markedly by SK in a time- and dose-dependent manner. In addition, the results of real-time reverse transcription-PCR (RT-PCR) demonstrated that the transcription level of YHB1 in C. albicans was greatly increased upon incubation of SK. Consistently, the YHB1-null mutant (yhb1Δ/Δ) exhibited a higher susceptibility to SK than wild-type cells. In addition, although the transcription level of CTA4 in C. albicans was not significantly changed when exposed to SK, the CTA4-null mutant (cta4Δ/Δ) was more susceptible to SK. Collectively, SK is the agent found to execute its antifungal activity directly via endogenous NO accumulation, and NO-mediated damage is related to the suppression of YHB1 and the function of CTA4. PMID:27530748

  14. Activity and expression of nitric oxide synthase in pork skeletal muscles.

    PubMed

    Liu, Rui; Li, Yu-pin; Zhang, Wan-gang; Fu, Qing-quan; Liu, Nian; Zhou, Guang-hong

    2015-01-01

    The objective of this study was to investigate the biochemical changes of nitric oxide synthase (NOS) in pork skeletal muscles during postmortem storage. Longissimus thoracis (LT), psoas major (PM) and semimembranosus (SM) muscles of pork were removed immediately after slaughter and stored under vacuum condition at 4°C for 0, 1 and 3d. Results showed that all three muscles exhibited NOS activity until 1d while SM muscle retained NOS activity after 3d of storage. The content of nNOS in SM muscle was stable across 3d of storage while decreased intensity of nNOS was detected at 1 and 3d of aging in PM and LT muscles due to the degradation of calpain. Immunostaining showed that nNOS was located at not only sarcolemma but also cytoplasm at 0 and 1d of storage. Our data suggest that postmortem muscles possess NOS activity and nNOS expression depends on muscle type. PMID:25280359

  15. Nitric oxide mediates N-methyl-D-aspartate receptor-induced activation of p21ras.

    PubMed

    Yun, H Y; Gonzalez-Zulueta, M; Dawson, V L; Dawson, T M

    1998-05-12

    N-methyl-D-aspartate (NMDA) glutamate receptor-mediated increases in intracellular calcium are thought to play a critical role in synaptic plasticity. The mechanisms by which changes in cytoplasmic calcium transmit the glutamate signal to the nucleus, which is ultimately important for long-lasting neuronal responses, are poorly understood. We show that NMDA receptor stimulation leads to activation of p21(ras) (Ras) through generation of nitric oxide (NO) via neuronal NO synthase. The competitive NO synthase inhibitor, L-nitroarginine methyl ester, prevents Ras activation elicited by NMDA and this effect is competitively reversed by the NO synthase substrate, L-arginine. NMDA receptor stimulation fails to activate Ras in neuronal cultures from mice lacking neuronal NO synthase. NMDA-induced Ras activation occurs through a cGMP-independent pathway as 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one (ODQ), a potent and selective inhibitor of guanylyl cyclase, has no effect on NMDA receptor-induced activation of Ras, and the cell-permeable cGMP analog, 8Br-cGMP, does not activate Ras. Furthermore, NO directly activates immunoprecipitated Ras from neurons. NMDA also elicits tyrosine phosphorylation of extracellular signal-regulated kinases, a downstream effector pathway of Ras, through a NO/non-cGMP dependent mechanism, thus supporting the physiologic relevance of endogenous NO regulation of Ras. These results suggest that Ras is a physiologic target of endogenously produced NO and indicates a signaling pathway for NMDA receptor activation that may be important for long-lasting neuronal responses.

  16. Nitric oxide synthase domain interfaces regulate electron transfer and calmodulin activation.

    PubMed

    Smith, Brian C; Underbakke, Eric S; Kulp, Daniel W; Schief, William R; Marletta, Michael A

    2013-09-17

    Nitric oxide (NO) produced by NO synthase (NOS) participates in diverse physiological processes such as vasodilation, neurotransmission, and the innate immune response. Mammalian NOS isoforms are homodimers composed of two domains connected by an intervening calmodulin-binding region. The N-terminal oxidase domain binds heme and tetrahydrobiopterin and the arginine substrate. The C-terminal reductase domain binds FAD and FMN and the cosubstrate NADPH. Although several high-resolution structures of individual NOS domains have been reported, a structure of a NOS holoenzyme has remained elusive. Determination of the higher-order domain architecture of NOS is essential to elucidate the molecular underpinnings of NO formation. In particular, the pathway of electron transfer from FMN to heme, and the mechanism through which calmodulin activates this electron transfer, are largely unknown. In this report, hydrogen-deuterium exchange mass spectrometry was used to map critical NOS interaction surfaces. Direct interactions between the heme domain, the FMN subdomain, and calmodulin were observed. These interaction surfaces were confirmed by kinetic studies of site-specific interface mutants. Integration of the hydrogen-deuterium exchange mass spectrometry results with computational docking resulted in models of the NOS heme and FMN subdomain bound to calmodulin. These models suggest a pathway for electron transfer from FMN to heme and a mechanism for calmodulin activation of this critical step.

  17. Nitric oxide synthase domain interfaces regulate electron transfer and calmodulin activation

    PubMed Central

    Smith, Brian C.; Underbakke, Eric S.; Kulp, Daniel W.; Schief, William R.; Marletta, Michael A.

    2013-01-01

    Nitric oxide (NO) produced by NO synthase (NOS) participates in diverse physiological processes such as vasodilation, neurotransmission, and the innate immune response. Mammalian NOS isoforms are homodimers composed of two domains connected by an intervening calmodulin-binding region. The N-terminal oxidase domain binds heme and tetrahydrobiopterin and the arginine substrate. The C-terminal reductase domain binds FAD and FMN and the cosubstrate NADPH. Although several high-resolution structures of individual NOS domains have been reported, a structure of a NOS holoenzyme has remained elusive. Determination of the higher-order domain architecture of NOS is essential to elucidate the molecular underpinnings of NO formation. In particular, the pathway of electron transfer from FMN to heme, and the mechanism through which calmodulin activates this electron transfer, are largely unknown. In this report, hydrogen–deuterium exchange mass spectrometry was used to map critical NOS interaction surfaces. Direct interactions between the heme domain, the FMN subdomain, and calmodulin were observed. These interaction surfaces were confirmed by kinetic studies of site-specific interface mutants. Integration of the hydrogen–deuterium exchange mass spectrometry results with computational docking resulted in models of the NOS heme and FMN subdomain bound to calmodulin. These models suggest a pathway for electron transfer from FMN to heme and a mechanism for calmodulin activation of this critical step. PMID:24003111

  18. Venous gas emboli and exhaled nitric oxide with simulated and actual extravehicular activity.

    PubMed

    Karlsson, Lars L; Blogg, S Lesley; Lindholm, Peter; Gennser, Mikael; Hemmingsson, Tryggve; Linnarsson, Dag

    2009-10-01

    The decompression experienced due to the change in pressure from a space vehicle (1013hPa) to that in a suit for extravehicular activity (EVA) (386hPa) was simulated using a hypobaric chamber. Previous ground-based research has indicated around a 50% occurrence of both venous gas emboli (VGE) and symptoms of decompression illness (DCI) after similar decompressions. In contrast, no DCI symptoms have been reported from past or current space activities. Twenty subjects were studied using Doppler ultrasound to detect any VGE during decompression to 386hPa, where they remained for up to 6h. Subjects were supine to simulate weightlessness. A large number of VGE were found in one subject at rest, who had a recent arm fracture; a small number of VGE were found in another subject during provocation with calf contractions. No changes in exhaled nitric oxide were found that can be related to either simulated EVA or actual EVA (studied in a parallel study on four cosmonauts). We conclude that weightlessness appears to be protective against DCI and that exhaled NO is not likely to be useful to monitor VGE.

  19. Measurement of Fractional Exhaled Nitric Oxide as a Marker of Disease Activity in Inflammatory Bowel Disease

    PubMed Central

    Ikonomi, Erkanda; Rothstein, Robin D.; Ehrlich, Adam C.; Friedenberg, Frank K.

    2016-01-01

    Background and Aims Definitive diagnosis of IBD requires endoscopic and pathologic confirmation. These tools are also used to classify disease activity. Our aim was to determine if the fractional exhaled nitric oxide (FeNO) could be utilized to screen for IBD and assess for disease activity. Methods We matched weighted IBD cases and controls from the 2009–2010 NHANES dataset. All subjects underwent measurement of FeNO using standardized techniques. We assessed for potential confounders for FeNO measurement including age, height, and asthma. For IBD subjects, we used the presence of diarrhea, fatigue, and weight loss as a proxy for IBD activity. Laboratory parameters examined to estimate disease activity included anemia (≤ 10 g/dl), iron deficiency (ferritin ≤ 20 ng/ml), hypoalbuminemia (≤ 3.2 g/dl), and CRP (≥ 1.1 mg/dl). Results The weighted sample represented 199,414,901 subjects. The weighted prevalence of IBD was 2,084,895 (1.0%). IBD subjects had nearly the same FeNO level as those without IBD (17.0 ± 16.2 vs. 16.7 ± 14.5 ppb). The odds of a FeNO > 25 ppb was half (OR=0.501; 95% CI 0.497–0.504) for subjects with IBD compared to those without IBD after controlling for confounders. The AUROC curve for FeNO was 0.47 (0.35–0.59). FeNO levels were not higher in patients with laboratory values suggestive of active disease. FeNO levels were higher in IBD patients with diarrhea, rectal urgency, and fatigue but were lower in those with unintentional weight loss. Conclusion Measurement of FeNO does not appear to be useful to screen for IBD or assess disease activity. PMID:27398403

  20. Nitric oxide-releasing poly(lactic-co-glycolic acid)-polyethylenimine nanoparticles for prolonged nitric oxide release, antibacterial efficacy, and in vivo wound healing activity.

    PubMed

    Nurhasni, Hasan; Cao, Jiafu; Choi, Moonjeong; Kim, Il; Lee, Bok Luel; Jung, Yunjin; Yoo, Jin-Wook

    2015-01-01

    Nitric oxide (NO)-releasing nanoparticles (NPs) have emerged as a wound healing enhancer and a novel antibacterial agent that can circumvent antibiotic resistance. However, the NO release from NPs over extended periods of time is still inadequate for clinical application. In this study, we developed NO-releasing poly(lactic-co-glycolic acid)-polyethylenimine (PEI) NPs (NO/PPNPs) composed of poly(lactic-co-glycolic acid) and PEI/diazeniumdiolate (PEI/NONOate) for prolonged NO release, antibacterial efficacy, and wound healing activity. Successful preparation of PEI/NONOate was confirmed by proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, and ultraviolet/visible spectrophotometry. NO/PPNPs were characterized by particle size, surface charge, and NO loading. The NO/PPNPs showed a prolonged NO release profile over 6 days without any burst release. The NO/PPNPs exhibited potent bactericidal efficacy against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa concentration-dependently and showed the ability to bind on the surface of the bacteria. We also found that the NO released from the NO/PPNPs mediates bactericidal efficacy and is not toxic to healthy fibroblast cells. Furthermore, NO/PPNPs accelerated wound healing and epithelialization in a mouse model of a MRSA-infected wound. Therefore, our results suggest that the NO/PPNPs presented in this study could be a suitable approach for treating wounds and various skin infections.

  1. Nitric oxide-releasing poly(lactic-co-glycolic acid)-polyethylenimine nanoparticles for prolonged nitric oxide release, antibacterial efficacy, and in vivo wound healing activity

    PubMed Central

    Nurhasni, Hasan; Cao, Jiafu; Choi, Moonjeong; Kim, Il; Lee, Bok Luel; Jung, Yunjin; Yoo, Jin-Wook

    2015-01-01

    Nitric oxide (NO)-releasing nanoparticles (NPs) have emerged as a wound healing enhancer and a novel antibacterial agent that can circumvent antibiotic resistance. However, the NO release from NPs over extended periods of time is still inadequate for clinical application. In this study, we developed NO-releasing poly(lactic-co-glycolic acid)-polyethylenimine (PEI) NPs (NO/PPNPs) composed of poly(lactic-co-glycolic acid) and PEI/diazeniumdiolate (PEI/NONOate) for prolonged NO release, antibacterial efficacy, and wound healing activity. Successful preparation of PEI/NONOate was confirmed by proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, and ultraviolet/visible spectrophotometry. NO/PPNPs were characterized by particle size, surface charge, and NO loading. The NO/PPNPs showed a prolonged NO release profile over 6 days without any burst release. The NO/PPNPs exhibited potent bactericidal efficacy against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa concentration-dependently and showed the ability to bind on the surface of the bacteria. We also found that the NO released from the NO/PPNPs mediates bactericidal efficacy and is not toxic to healthy fibroblast cells. Furthermore, NO/PPNPs accelerated wound healing and epithelialization in a mouse model of a MRSA-infected wound. Therefore, our results suggest that the NO/PPNPs presented in this study could be a suitable approach for treating wounds and various skin infections. PMID:25960648

  2. Nitric oxide-releasing poly(lactic-co-glycolic acid)-polyethylenimine nanoparticles for prolonged nitric oxide release, antibacterial efficacy, and in vivo wound healing activity.

    PubMed

    Nurhasni, Hasan; Cao, Jiafu; Choi, Moonjeong; Kim, Il; Lee, Bok Luel; Jung, Yunjin; Yoo, Jin-Wook

    2015-01-01

    Nitric oxide (NO)-releasing nanoparticles (NPs) have emerged as a wound healing enhancer and a novel antibacterial agent that can circumvent antibiotic resistance. However, the NO release from NPs over extended periods of time is still inadequate for clinical application. In this study, we developed NO-releasing poly(lactic-co-glycolic acid)-polyethylenimine (PEI) NPs (NO/PPNPs) composed of poly(lactic-co-glycolic acid) and PEI/diazeniumdiolate (PEI/NONOate) for prolonged NO release, antibacterial efficacy, and wound healing activity. Successful preparation of PEI/NONOate was confirmed by proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, and ultraviolet/visible spectrophotometry. NO/PPNPs were characterized by particle size, surface charge, and NO loading. The NO/PPNPs showed a prolonged NO release profile over 6 days without any burst release. The NO/PPNPs exhibited potent bactericidal efficacy against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa concentration-dependently and showed the ability to bind on the surface of the bacteria. We also found that the NO released from the NO/PPNPs mediates bactericidal efficacy and is not toxic to healthy fibroblast cells. Furthermore, NO/PPNPs accelerated wound healing and epithelialization in a mouse model of a MRSA-infected wound. Therefore, our results suggest that the NO/PPNPs presented in this study could be a suitable approach for treating wounds and various skin infections. PMID:25960648

  3. C-Type Natriuretic Peptide Induces Anti-contractile Effect Dependent on Nitric Oxide, Oxidative Stress, and NPR-B Activation in Sepsis

    PubMed Central

    Pernomian, Laena; Prado, Alejandro F.; Silva, Bruno R.; Azevedo, Aline; Pinheiro, Lucas C.; Tanus-Santos, José E.; Bendhack, Lusiane M.

    2016-01-01

    Aims: To evaluate the role of nitric oxide, reactive oxygen species (ROS), and natriuretic peptide receptor-B activation in C-type natriuretic peptide-anti-contractile effect on Phenylephrine-induced contraction in aorta isolated from septic rats. Methods and Results: Cecal ligation and puncture (CLP) surgery was used to induce sepsis in male rats. Vascular reactivity was conducted in rat aorta and resistance mesenteric artery (RMA). Measurement of survival rate, mean arterial pressure (MAP), plasma nitric oxide, specific protein expression, and localization were evaluated. Septic rats had a survival rate about 37% at 4 h after the surgery, and these rats presented hypotension compared to control-operated (Sham) rats. Phenylephrine-induced contraction was decreased in sepsis. C-type natriuretic peptide (CNP) induced anti-contractile effect in aortas. Plasma nitric oxide was increased in sepsis. Nitric oxide-synthase but not natriuretic peptide receptor-B expression was increased in septic rat aortas. C-type natriuretic peptide-anti-contractile effect was dependent on nitric oxide-synthase, ROS, and natriuretic peptide receptor-B activation. Natriuretic peptide receptor-C, protein kinase-Cα mRNA, and basal nicotinamide adenine dinucleotide phosphate (NADPH)-dependent ROS production were lower in septic rats. Phenylephrine and CNP enhanced ROS production. However, stimulated ROS production was low in sepsis. Conclusion: CNP induced anti-contractile effect on Phenylephrine contraction in aortas from Sham and septic rats that was dependent on nitric oxide-synthase, ROS, and natriuretic peptide receptor-B activation. PMID:27445832

  4. Activation of the Escherichia coli SoxRS-regulon by nitric oxide and its physiological donors.

    PubMed

    Vasil'eva, S V; Stupakova, M V; Lobysheva, I I; Mikoyan, V D; Vanin, A F

    2001-09-01

    Activation of the Escherichia coli SoxRS-regulon by nitric oxide (NO) and its physiological donors (S-nitrosothiol (GS-NO) and dinitrosyl iron complexes with glutathione (DNIC(glu)) and cysteine (DNIC(cys)) ligands) has been studied. To elucidate the molecular mechanisms of signal transduction via nitrosylation of Fe-S-centers in SoxR, the ability of pure NO and NO-producing agents to activate the SoxRS-regulon in E. coli cells bearing a soxS::lacZ operon (promoter) fusion has been compared. EPR spectroscopy of whole cells has been used to monitor the formation of inducible protein-DNIC complexes. DNIC(cys), GS-NO, and pure NO appeared to be potent inducers of soxS expression, whereas DNIC(glu) was considerably less efficient. Thus, lower in vitro stability of DNIC(cys) was in contrast with its higher biological activity. Pretreatment of the cells with o-phenanthroline, a chelating agent for iron, prevented soxS expression by GS-NO. Treatment of intact E. coli cells with DNIC, GS-NO, and NO at equimolar concentration 150 microM resulted in formation of a single EPR-detectable DNIC-type signal with g = 2.03. The initial stage in the SoxR transcription activity is supposed to include two steps: first, DNIC primers are formed from exogenous NO and free iron, and then these DNIC disintegrate SoxR [2Fe-2S] clusters and thus activate SoxRS-regulon transcription. PMID:11703180

  5. [Nitric oxide and nitric oxide synthase related to male reproduction].

    PubMed

    Ji, Jiajia; Zhao, Yanfang; Chen, Guoyuan

    2007-09-01

    Nitric oxide (NO) may be a kind of signal molecule which may have multiplicate physiological function such as secondary messenger, neurotransmitter and effect molecule. NO may play a crucial role in organism. The production of NO can not get away from nitric oxide synthase (NOS) which may distribute in almost all kind of organs of male reproductive system. NO and NOS may have the function of bifunctional regulation for reproduction. In this paper, the regulatory function of NO and NOS on male reproductive system were reviewed.

  6. Calcium-activated potassium channels in cultured human endothelial cells are not directly modulated by nitric oxide.

    PubMed

    Haburcák, M; Wei, L; Viana, F; Prenen, J; Droogmans, G; Nilius, B

    1997-04-01

    Nitric oxide has been proposed to directly activated large conductance Ca(2+)-dependent K+ channels (BKCa) [Bolotina V.M., Najibi S., Palacino J.J., Pagano P.J., Cohen R.A. Nitric oxide directly activates calcium-dependent potassium channels in vascular smooth muscle. Nature 1994; 368: 850-853]. The nitric oxide (NO) donor S-nitrosocysteine (SNOC) was used to evaluate a possible direct modulation of BKCa by NO in EAhy926 (EA cells), a cultured human umbilical vein derived endothelial cell line, using the whole-cell, cell-attached and inside-out configuration of the patch-clamp technique, together with simultaneous amperometric measurement of NO and the concentration of free intracellular calcium [Ca2+]i. BKCa channels with a large conductance of approximately 190 pS, voltage-dependent activation and a reversal potential close to -80 mV have been identified in EA cells. Exposure of EA cells in the experimental chamber to 1 mM SNOC delivered approximately 5 microM NO, as recorded by an amperometric probe in situ. SNOC produced a modest increases in [Ca2+]i that was insufficient to activate BKCa channels. NO alone neither activated BKCa channels directly nor modulated preactivated BKCa channels in EA cells. These results do not support a direct modulatory effect of NO on large conductance BKCa channels in cultured endothelial cells. PMID:9160165

  7. Nitric oxide and nitric oxide-generating agents induce a reversible inactivation of protein kinase C activity and phorbol ester binding.

    PubMed

    Gopalakrishna, R; Chen, Z H; Gundimeda, U

    1993-12-25

    Since S-nitrosylation of protein thiols is one of the cellular regulatory mechanisms induced by nitric oxide (NO), and since protein kinase C (PKC) has critical thiol residues which influence its kinase activity, we have determined whether NO could regulate this enzyme. Initial studies were carried out with purified PKC and the NO-generating agent S-nitrosocysteine. This agent decreased phosphotransferase activity of PKC in a Ca(2+)- and oxygen-dependent manner with an IC50 of 75 microM. Phorbol ester binding was affected partially only at higher concentrations (> 100 microM) of S-nitrosocysteine. This inactivation of PKC was blocked by the NO scavenger oxyhemoglobin or reversed by dithiothreitol. It is likely that NO initially induced an S-nitrosylation of vicinal thiols, which were then oxidized to form an intramolecular disulfide. Other NO-generating agents such as S-nitroso-N-acetylpenicillamine and sodium nitroprusside, as well as authentic NO gas, induced similar types of PKC modifications. In intact B16 melanoma cells treated with S-nitrosocysteine a rapid decrease in PKC activity in both cytosol and membrane was observed. Unlike in experiments with purified PKC, in intact cells treated with S-nitrosocysteine the phorbol ester binding also decreased to a rate equal to that of PKC activity. These modifications were readily reversed by treating the homogenates with dithiothreitol in test tubes or by removing the NO-generating source from intact cells. To determine whether the limited amounts of NO generated within the intact cells could induce this type of PKC modification, the macrophage cell line IC-21 was treated with lipopolysacharide and Ca2+ ionophore A23187 to induce the NO production. With an increase in generation of NO (3-12-h period) in these cells, a parallel and irreversible decrease in PKC activity and phorbol ester binding was observed. A specific inhibitor for NO synthase, NG-monomethyl-L-arginine, inhibited both the production of NO and PKC

  8. Effect of nitric oxide on mitochondrial respiratory activity of human articular chondrocytes

    PubMed Central

    Maneiro, E; Lopez-Armada, M; de Andres, M C; Carames, B; Martin, M; Bonilla, A; del Hoyo, P; Galdo, F; Arenas, J; Blanco, F

    2005-01-01

    Objective: To investigate the effect of nitric oxide (NO) on mitochondrial activity and its relation with the apoptosis of human articular chondrocytes. Materials and methods: Mitochondrial function was evaluated by analysing respiratory chain enzyme complexes, citrate synthase (CS) activities, and mitochondrial membrane potential (Δψm). The activities of the mitochondrial respiratory chain (MRC) complexes (complex I: NADH CoQ1 reductase, complex II: succinate dehydrogenase, complex III: ubiquinol cytochrome c reductase, complex IV: cytochrome c oxidase) and CS were measured in human articular chondrocytes isolated from normal cartilage. The Δψm was measured by 5,5',6,6'-tetracholoro-1,1',3,3'-tetraethylbenzimidazole carbocyanide iodide (JC-1) using flow cytometry. Apoptosis was analysed by flow cytometry. The mRNA expression of caspases was analysed by ribonuclease protection analysis and the detection of protein synthesis by western blotting. Sodium nitroprusside (SNP) was used as an NO compound donor. Results: SNP at concentrations higher than 0.5 mmol/l for 24 hours induced cellular changes characteristic of apoptosis. SNP elicited mRNA expression of caspase-3 and caspase-7 and down regulated bcl-2 synthesis in a dose and time dependent manner. Furthermore, 0.5 mM SNP induced depolarisation of the mitochondrial membrane at 5, 12, and 24 hours. Analysis of the MRC showed that at 5 hours, 0.5 mM SNP reduced the activity of complex IV by 33%. The individual inhibition of mitochondrial complex IV with azide modified the Δψm and induced apoptosis. Conclusions: This study suggests that the effect of NO on chondrocyte survival is mediated by its effect on complex IV of the MRC. PMID:15708893

  9. Enhanced mucosal permeability and nitric oxide synthase activity in jejunum of mast cell deficient mice

    PubMed Central

    Komatsu, S; Grisham, M; Russell, J; Granger, D

    1997-01-01

    Background—Recent reports have described a modulating influence of nitric oxide (NO) on intestinal mucosal permeability and have implicated a role for mast cells in this NO mediated process. 
Aims—To assess further the contribution of mast cells to the mucosal permeability changes elicited by the NO synthase (NOS) inhibitor NG-nitro-L-arginine methylester (L-NAME), using mast cell deficient (W/WV) and mast cell replete mice (+/+). 
Methods—Chromium-51 EDTA clearance (from blood to jejunal lumen), jejunal NOS and myeloperoxidase (MPO) activities, and plasma nitrate/nitrite levels were monitored. 
Results—The increased EDTA clearance elicited by intraluminal L-NAME in W/WV mice (4.4-fold) was significantly greater than the response observed in control (+/+) mice (1.8-fold). The exacerbated response in W/Wv mice was greatly attenuated by pretreatment with either dexamethasone (1.3-fold) or the selective inducible NOS inhibitor, aminoguanidine (1.4-fold), and partially attenuated by the mast cell stabiliser, lodoxamide (2.9-fold). Jejunal inducible NOS activity was significantly higher in W/WV than in +/+ mice, while jejunal MPO was lower in W/WV mice than in +/+ mice, suggesting that the higher inducible NOS in W/WV does not result from the recruitment of inflammatory cells into the gut. The higher inducible NOS activity in the jejunum of W/WV was significantly reduced by dexamethasone treatment. 
Conclusions—Our results suggest that mast cells normally serve to inhibit inducible NOS activity tonically in the gut and that inhibitors of NOS elicit a larger permeability response when this tonic inhibitory influence is released by mast cell depletion. 

 Keywords: aminoguanidine; c-kit; dexamethasone; epithelium; neutrophils PMID:9414970

  10. Endoplasmic Reticulum Stress-Sensing Mechanism Is Activated in Entamoeba histolytica upon Treatment with Nitric Oxide

    PubMed Central

    Santi-Rocca, Julien; Smith, Sherri; Weber, Christian; Pineda, Erika; Hon, Chung-Chau; Saavedra, Emma; Olivos-García, Alfonso; Rousseau, Sandrine; Dillies, Marie-Agnès; Coppée, Jean-Yves; Guillén, Nancy

    2012-01-01

    The Endoplasmic Reticulum stores calcium and is a site of protein synthesis and modification. Changes in ER homeostasis lead to stress responses with an activation of the unfolded protein response (UPR). The Entamoeba histolytica endomembrane system is simple compared to those of higher eukaryotes, as a canonical ER is not observed. During amoebiasis, an infection of the human intestine and liver by E. histolytica, nitric oxide (NO) triggers an apoptotic-like event preceded by an impairment of energy production and a loss of important parasite pathogenic features. We address the question of how this ancient eukaryote responds to stress induced by immune components (i.e. NO) and whether stress leads to ER changes and subsequently to an UPR. Gene expression analysis suggested that NO triggers stress responses marked by (i) dramatic up-regulation of hsp genes although a bona fide UPR is absent; (ii) induction of DNA repair and redox gene expression and iii) up-regulation of glycolysis-related gene expression. Enzymology approaches demonstrate that NO directly inhibits glycolysis and enhance cysteine synthase activity. Using live imaging and confocal microscopy we found that NO dramatically provokes extensive ER fragmentation. ER fission in E. histolytica appears as a protective response against stress, as it has been recently proposed for neuron self-defense during neurologic disorders. Chronic ER stress is also involved in metabolic diseases including diabetes, where NO production reduces ER calcium levels and activates cell death. Our data highlighted unique cellular responses of interest to understand the mechanisms of parasite death during amoebiasis. PMID:22384074

  11. Introducing a 2-His-1-Glu Nonheme Iron Center into Myoglobin Confers Nitric Oxide Reductase Activity

    SciTech Connect

    Y Lin; N Yeung; Y Gao; K Miner; L Lei; H Robinson; Y Lu

    2011-12-31

    A conserved 2-His-1-Glu metal center, as found in natural nonheme iron-containing enzymes, was engineered into sperm whale myoglobin by replacing Leu29 and Phe43 with Glu and His, respectively (swMb L29E, F43H, H64, called Fe{sub B}Mb(-His)). A high resolution (1.65 {angstrom}) crystal structure of Cu(II)-CN{sup -}-Fe{sub B}Mb(-His) was determined, demonstrating that the unique 2-His-1-Glu metal center was successfully created within swMb. The Fe{sub B}Mb(-His) can bind Cu, Fe, or Zn ions, with both Cu(I)-Fe{sub B}Mb(-His) and Fe(II)-Fe{sub B}Mb(-His) exhibiting nitric oxide reductase (NOR) activities. Cu dependent NOR activity was significantly higher than that of Fe in the same metal binding site. EPR studies showed that the reduction of NO to N{sub 2}O catalyzed by these two enzymes resulted in different intermediates; a five-coordinate heme-NO species was observed for Cu(I)-Fe{sub B}Mb(-His) due to the cleavage of the proximal heme Fe-His bond, while Fe(II)-Fe{sub B}Mb(-His) remained six-coordinate. Therefore, both the metal ligand, Glu29, and the metal itself, Cu or Fe, play crucial roles in NOR activity. This study presents a novel protein model of NOR and provides insights into a newly discovered member of the NOR family, gNOR.

  12. Introducing a 2-His-1-Glu Nonheme Iron Center into Myoglobin Confers Nitric Oxide Reductase Activity

    SciTech Connect

    Lin, Y.W.; Robinson, H.; Yeung, N.; Gao, Y.-G.; Miner, K. D.; Lei, L.; Lu, Y.

    2010-07-28

    A conserved 2-His-1-Glu metal center, as found in natural nonheme iron-containing enzymes, was engineered into sperm whale myoglobin by replacing Leu29 and Phe43 with Glu and His, respectively (swMb L29E, F43H, H64, called Fe{sub B}Mb(-His)). A high resolution (1.65 {angstrom}) crystal structure of Cu(II)-CN?-Fe{sub B}Mb(-His) was determined, demonstrating that the unique 2-His-1-Glu metal center was successfully created within swMb. The Fe{sub B}Mb(-His) can bind Cu, Fe, or Zn ions, with both Cu(I)-Fe{sub B}Mb(-His) and Fe(II)-Fe{sub B}Mb(-His) exhibiting nitric oxide reductase (NOR) activities. Cu dependent NOR activity was significantly higher than that of Fe in the same metal binding site. EPR studies showed that the reduction of NO to N{sub 2}O catalyzed by these two enzymes resulted in different intermediates; a five-coordinate heme-NO species was observed for Cu(I)-Fe{sub B}Mb(-His) due to the cleavage of the proximal heme Fe-His bond, while Fe(II)-Fe{sub B}Mb(-His) remained six-coordinate. Therefore, both the metal ligand, Glu29, and the metal itself, Cu or Fe, play crucial roles in NOR activity. This study presents a novel protein model of NOR and provides insights into a newly discovered member of the NOR family, gNOR.

  13. Analytical Chemistry of Nitric Oxide

    PubMed Central

    Hetrick, Evan M.

    2013-01-01

    Nitric oxide (NO) is the focus of intense research, owing primarily to its wide-ranging biological and physiological actions. A requirement for understanding its origin, activity, and regulation is the need for accurate and precise measurement techniques. Unfortunately, analytical assays for monitoring NO are challenged by NO’s unique chemical and physical properties, including its reactivity, rapid diffusion, and short half-life. Moreover, NO concentrations may span pM to µM in physiological milieu, requiring techniques with wide dynamic response ranges. Despite such challenges, many analytical techniques have emerged for the detection of NO. Herein, we review the most common spectroscopic and electrochemical methods, with special focus on the fundamentals behind each technique and approaches that have been coupled with modern analytical measurement tools or exploited to create novel NO sensors. PMID:20636069

  14. Effect of nitric oxide on μ-calpain activation, protein proteolysis, and protein oxidation of pork during post-mortem aging.

    PubMed

    Li, Yu-pin; Liu, Rui; Zhang, Wan-gang; Fu, Qing-quan; Liu, Nian; Zhou, Guang-hong

    2014-06-25

    The aim of the current research was to examine the influence of nitric oxide (NO) on calpain activation, protein proteolysis, and oxidation in post-mortem pork. Five longissimus muscles were removed from carcass after slaughter, and samples were incubated with water, nitric oxide synthase (NOS) inhibitor, or NO donor for 24 h at 4 °C. The samples were taken out and then stored under 4 °C for 1, 4, and 7 d. Results showed that autolysis of μ-calpain increased by incubation with NOS inhibitor after storage for 1 d (P<0.05). Degradation of titin and nebulin increased by treatment of NOS inhibitor among three treatments (P<0.05). Higher levels of protein oxidation were observed after samples incubated with NO donor than treatment of NOS inhibitor (P<0.05). These data indicated that NO could participate in regulating calpain activation and its proteolysis activity during post-mortem aging.

  15. Experimental colitis is ameliorated by inhibition of nitric oxide synthase activity.

    PubMed Central

    Rachmilewitz, D; Karmeli, F; Okon, E; Bursztyn, M

    1995-01-01

    Enhanced nitric oxide (NO) generation by stimulated NO synthase (NOS) activity may, through its oxidative metabolism contribute to tissue injury in experimental colitis. In this study the possible amelioration of experimental colitis by NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NOS activity, was evaluated. Colitis was induced in rats by intracolonic administration of 30 mg trinitrobenzene sulphonic acid (TNB) dissolved in 0.25 ml 50% ethanol or by flushing the colon of capsaicin pretreated rats with 2 ml of 5% acetic acid. In several experiments, L-NAME 0.1 mg/ml was added to the drinking water at the time of colitis induction with TNB or seven days before acetic acid treatment. Rats were killed at various time intervals after induction of colitis. A 10 cm distal colonic segment was isolated, weighed, lesion area measured, and explants organ cultured for 24 hours for determination of NO generation by the Greiss reaction. The rest of the mucosa was scraped for determination of myeloperoxidase and NOS activities and leukotriene generation. In TNB treated rats mean arterial pressure was also determined up to 72 hours after damage induction, with or without cotreatment with nitroprusside. L-NAME significantly decreased the extent of tissue injury in TNB treated rats. Seven days after TNB treatment lesion area was reduced by 55%, colonic weight by 37%, and myeloperoxidase and NOS activity by 59% and 42%, respectively. Acetic acid induced colitis in capsaicin pretreated rats was also significantly decreased by L-NAME. Twenty four hours after acetic acid treatment lesion area was reduced by 61%, colonic weight by 21% and NOS activity by 39%. Mean (SEM) arterial blood pressure in TNB+L-NAME treated rats was 37.6 (8.1) mm Hg higher than in TNB treated rats, an effect that was only partially abolished by nitroprusside. These results show that inhibition of NO synthesis by an L-arginine analogue significantly ameliorates the extent of tissue injury in two

  16. Role of Nitric Oxide in the Chemistry and Anticancer Activity of Etoposide (VP-16,213)

    PubMed Central

    Sinha, Birandra K.; Bhattacharjee, Suchandra; Chatterjee, Saurabh; Jiang, JinJie; Motten, Ann G.; Kumar, Ashutosh; Espey, Michael Graham; Mason, Ronald P.

    2013-01-01

    Originally identified as an innate cytotoxin, nitric oxide (•NO) formation in tumors can influence chemotherapy and exacerbate cancer progression. Here, we examined the hypothesis that •NO generation contributes to cancer cell drug resistance towards the widely used anticancer drug Etoposide (VP-16). The UV-V is spectrum of VP-16 was not changed by exposure of VP-16 to •NO in aqueous buffer. In contrast, reddish-orange compound(s) characteristic of o-quinone- and nitroso-VP-16, were readily generated in a hydrophobic medium (chloroform) in an oxygen-dependent manner. Similar products were also formed when the VP-16 radical, generated from VP-16 and horseradish peroxidase/H2O2, was exposed directly to •NO in chloroform in the presence of oxygen. Separation and spectral analysis of VP-16 reaction extracts by electron spin resonance and UV-Vis indicated generation of the phenoxy radical and the o-quinone of VP-16, as well as putative nitroxide, iminoxyl and other nitrogen oxide intermediates. Nitric oxide products of VP-16 displayed significantly diminished topoisomerase II-dependent cleavage of DNA and cytotoxicity to human HL-60 leukemia cells. LPS-mediated induction of nitric oxide synthase in murine macrophages resulted in VP-16 resistance compared to Raw cells. Furthermore, •NO products derived from iNOS rapidly reacted with VP-16 leading to decreased DNA damage and cytotoxicity. Together, these observations suggest that formation of •NO in tumors (associated macrophages) can contribute to VP-16 resistance via detoxification of VP-16. PMID:23402364

  17. Activation of protease calpain by oxidized and glycated LDL increases the degradation of endothelial nitric oxide synthase

    PubMed Central

    Dong, Yunzhou; Wu, Yong; Wu, Mingyuan; Wang, Shuangxi; Zhang, Junhua; Xie, Zhonglin; Xu, Jian; Song, Ping; Wilson, Kenneth; Zhao, Zhengxing; Lyons, Timothy; Zou, Ming-Hui

    2009-01-01

    Oxidation and glycation of low-density lipoprotein (LDL) promote vascular injury in diabetes; however, the mechanisms underlying this effect remain poorly defined. The present study was conducted to determine the effects of ‘heavily oxidized’ glycated LDL (HOG-LDL) on endothelial nitric oxide synthase (eNOS) function. Exposure of bovine aortic endothelial cells with HOG-LDL reduced eNOS protein levels in a concentration- and time-dependent manner, without altering eNOS mRNA levels. Reduced eNOS protein levels were accompanied by an increase in intracellular Ca2+, augmented production of reactive oxygen species (ROS) and induction of Ca2+-dependent calpain activity. Neither eNOS reduction nor any of these other effects were observed in cells exposed to native LDL. Reduction of intracellular Ca2+ levels abolished eNOS reduction by HOG-LDL, as did pharmacological or genetic through calcium channel blockers or calcium chelator BAPTA or inhibition of NAD(P)H oxidase (with apocynin) or inhibition of calpain (calpain 1-specific siRNA). Consistent with these results, HOG-LDL impaired acetylcholine-induced endothelium-dependent vasorelaxation of isolated mouse aortas, and pharmacological inhibition of calpain prevented this effect. HOG-LDL may impair endothelial function by inducing calpain-mediated eNOS degradation in a ROS- and Ca2+-dependent manner. PMID:18624772

  18. YC-1 potentiates cAMP-induced CREB activation and nitric oxide production in alveolar macrophages

    SciTech Connect

    Hwang, Tsong-Long; Tang, Ming-Chi; Kuo, Liang-Mou; Chang, Wen-De; Chung, Pei-Jen; Chang, Ya-Wen; Fang, Yao-Ching

    2012-04-15

    Alveolar macrophages play significant roles in the pathogenesis of several inflammatory lung diseases. Increases in exhaled nitric oxide (NO) are well documented to reflect disease severity in the airway. In this study, we investigated the effect of 3-(5′-hydroxymethyl-2′-furyl)-1-benzyl indazole (YC-1), a known activator of soluble guanylyl cyclase, on prostaglandin (PG)E{sub 1} (a stable PGE{sub 2} analogue) and forskolin (a adenylate cyclase activator) induced NO production and inducible NO synthase (iNOS) expression in rat alveolar macrophages (NR8383). YC-1 did not directly cause NO production or iNOS expression, but drastically potentiated PGE{sub 1}- or forskolin-induced NO production and iNOS expression in NR8383 alveolar macrophages. Combination treatment with YC-1 and PGE{sub 1} significantly increased phosphorylation of the cAMP response element-binding protein (CREB), but not nuclear factor (NF)-κB activation. The combined effect on NO production, iNOS expression, and CREB phosphorylation was reversed by a protein kinase (PK)A inhibitor (H89), suggesting that the potentiating functions were mediated through a cAMP/PKA signaling pathway. Consistent with this, cAMP analogues, but not the cGMP analogue, caused NO release, iNOS expression, and CREB activation. YC-1 treatment induced an increase in PGE{sub 1}-induced cAMP formation, which occurred through the inhibition of cAMP-specific phosphodiesterase (PDE) activity. Furthermore, the combination of rolipram (an inhibitor of PDE4), but not milronone (an inhibitor of PDE3), and PGE{sub 1} also triggered NO production and iNOS expression. In summary, YC-1 potentiates PGE{sub 1}-induced NO production and iNOS expression in alveolar macrophages through inhibition of cAMP PDE activity and activation of the cAMP/PKA/CREB signaling pathway. Highlights: ► YC-1 potentiated PGE1-induced iNOS expression in alveolar macrophages. ► The combination of YC-1 and PGE1 increased CREB but not NFκB activation.

  19. Mangiferin Prevents Guinea Pig Tracheal Contraction via Activation of the Nitric Oxide-Cyclic GMP Pathway

    PubMed Central

    Vieira, Aline B.; Coelho, Luciana P.; Insuela, Daniella B. R.; Carvalho, Vinicius F.; dos Santos, Marcelo H.; Silva, Patricia MR.; Martins, Marco A.

    2013-01-01

    Previous studies have described the antispasmodic effect of mangiferin, a natural glucoside xanthone (2-C-β-Dgluco-pyranosyl-1,3,6,7-tetrahydroxyxanthone) that is present in mango trees and other plants, but its mechanism of action remains unknown. The aim of this study was to examine the potential contribution of the nitric oxide-cyclic GMP pathway to the antispasmodic effect of mangiferin on isolated tracheal rings preparations. The functional effect of mangiferin on allergic and non-allergic contraction of guinea pig tracheal rings was assessed in conventional organ baths. Cultured tracheal rings were exposed to mangiferin or vehicle, and nitric oxide synthase (NOS) 3 and cyclic GMP (cGMP) levels were quantified using western blotting and enzyme immunoassays, respectively. Mangiferin (0.1–10 µM) inhibited tracheal contractions induced by distinct stimuli, such as allergen, histamine, 5-hydroxytryptamine or carbachol, in a concentration-dependent manner. Mangiferin also caused marked relaxation of tracheal rings that were precontracted by carbachol, suggesting that it has both anti-contraction and relaxant properties that are prevented by removing the epithelium. The effect of mangiferin was inhibited by the nitric oxide synthase inhibitor, Nω-nitro-L-arginine methyl ester (L-NAME) (100 µM), and the soluble guanylate cyclase inhibitor, 1H-[1], [2], [4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) (10 µM), but not the adenylate cyclase inhibitor, 9-(tetrahydro-2-furyl)adenine (SQ22536) (100 µM). The antispasmodic effect of mangiferin was also sensitive to K+ channel blockers, such as tetraethylammonium (TEA), glibenclamide and apamin. Furthermore, mangiferin inhibited Ca2+-induced contractions in K+ (60 mM)-depolarised tracheal rings preparations. In addition, mangiferin increased NOS3 protein levels and cGMP intracellular levels in cultured tracheal rings. Finally, mangiferin-induced increase in cGMP levels was abrogated by co-incubation with either ODQ or L

  20. Effect of carbenoxolone on the biological activity of nitric oxide: relation to gastroprotection.

    PubMed Central

    Dembinska-Kiec, A.; Pallapies, D.; Simmet, T.; Peskar, B. M.; Peskar, B. A.

    1991-01-01

    1. The interactions between carbenoxolone and nitric oxide (NO) were examined by investigating their effects on human platelet aggregation, on rat aortic strips precontracted by phenylephrine and on protection of rat gastric mucosa against ethanol-induced injury. 2. Carbenoxolone (100-300 microM) caused a significant and concentration-dependent potentiation of rat peritoneal neutrophil (RPN)- 3-morpholino-syndnonimine (SIN-1)- or iloprost-induced inhibition of platelet aggregation. Higher concentrations (500 microM) of carbenoxolone alone markedly inhibited platelet aggregation. Pretreatment with carbenoxolone (100-300 microM) antagonized the reversal of the RPN- or SIN-1-induced antiaggregatory effect by oxyhaemoglobin (10 microM). 3. Rat aortic strips with intact endothelium precontracted by phenylephrine (0.1-0.3 microM) were relaxed by carbenoxolone (100-300 microM) in a concentration-dependent manner. Relaxations were abolished by mechanical removal of the endothelium or by incubation with methylene blue (10 microM) or NG-nitro-L-arginine (L-NNA, 100 microM). Sodium nitroprusside (10 nM)-induced relaxations of endothelium-denuded rat aortic strips were potentiated by carbenoxolone (100 microM). . The carbenoxolone (200 mg kg-1, p.o.)-induced gastroprotection against ethanol was antagonized by L-NNA (5-40 mg kg-1) in a dose-dependent manner. Pretreatment of rats with indomethacin (10 mg kg-1, s.c.) increased the effect of L-NNA. 5. The results suggest that the activity of carbenoxolone in the experimental systems tested is due to phosphodiesterase inhibition, although radical scavenging properties of the drug could contribute to some of the effects observed. In the rat gastric mucosa both increased prostaglandin levels and effects on the NO system could contribute to the protective action of carbenoxolone. PMID:1725764

  1. Nitric oxide activates leak K+ currents in the presumed cholinergic neuron of basal forebrain.

    PubMed

    Kang, Youngnam; Dempo, Yoshie; Ohashi, Atsuko; Saito, Mitsuru; Toyoda, Hiroki; Sato, Hajime; Koshino, Hisashi; Maeda, Yoshinobu; Hirai, Toshihiro

    2007-12-01

    Learning and memory are critically dependent on basal forebrain cholinergic (BFC) neuron excitability, which is modulated profoundly by leak K(+) channels. Many neuromodulators closing leak K(+) channels have been reported, whereas their endogenous opener remained unknown. We here demonstrate that nitric oxide (NO) can be the endogenous opener of leak K(+) channels in the presumed BFC neurons. Bath application of 1 mM S-nitroso-N-acetylpenicillamine (SNAP), an NO donor, induced a long-lasting hyperpolarization, which was often interrupted by a transient depolarization. Soluble guanylyl cyclase inhibitors prevented SNAP from inducing hyperpolarization but allowed SNAP to cause depolarization, whereas bath application of 0.2 mM 8-bromoguanosine-3',5'-cyclomonophosphate (8-Br-cGMP) induced a similar long-lasting hyperpolarization alone. These observations indicate that the SNAP-induced hyperpolarization and depolarization are mediated by the cGMP-dependent and -independent processes, respectively. When examined with the ramp command pulse applied at -70 mV under the voltage-clamp condition, 8-Br-cGMP application induced the outward current that reversed at K(+) equilibrium potential (E(K)) and displayed Goldman-Hodgkin-Katz rectification, indicating the involvement of voltage-independent K(+) current. By contrast, SNAP application in the presumed BFC neurons either dialyzed with the GTP-free internal solution or in the presence of 10 muM Rp-8-bromo-beta-phenyl-1,N(2)-ethenoguanosine 3',5'-cyclic monophosphorothioate sodium salt, a protein kinase G (PKG) inhibitor, induced the inward current that reversed at potentials much more negative than E(K) and close to the reversal potential of Na(+)-K(+) pump current. These observations strongly suggest that NO activates leak K(+) channels through cGMP-PKG-dependent pathway to markedly decrease the excitability in BFC neurons, while NO simultaneously causes depolarization by the inhibition of Na(+)-K(+) pump through ATP

  2. Modulation of haem oxygenase-1 expression by nitric oxide and leukotrienes in zymosan-activated macrophages

    PubMed Central

    Vicente, Ana María; Guillén, María Isabel; Alcaraz, María José

    2001-01-01

    Phagocytosis of unopsonized zymosan by RAW 264.7 macrophages upregulated protein expression of haem oxygenase-1 (HO-1), inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2) in a time- and concentration-dependent manner. In the presence of zymosan, exogenous prostaglandin E2 (PGE2) did not exert significant effects on the expression of these three enzymes. In contrast, exogenous leukotriene B4 (LTB4) and LTC4 in the nanomolar range inhibited HO-1 and iNOS expression, as well as nitrite accumulation. The COX inhibitors indomethacin and NS398 weakly inhibited HO-1 expression but had no effect on iNOS and COX-2 expression or nitrite. In contrast, the 5-lipoxygenase (5-LO) inhibitor ZM 230,487 significantly decreased HO-1, iNOS and nitrite, which were not affected by zileuton. Dexamethasone showed an inhibitory effect on HO-1 expression induced by zymosan. ZM 230,487 but not zileuton, inhibited the shift due to nuclear factor-κB (NF-κB), whereas they did not modify activator protein-1 (AP-1) binding. Our results suggest that inhibition of NF-κB binding could mediate the effects of ZM 230,487 on the modulation of HO-1 and iNOS protein expression. NOS inhibition by L-NG-nitroarginine methyl ester (L-NAME) or 1400 W abolished nitrite production and strongly reduced HO-1 expression. These results show an induction of HO-1 protein expression by zymosan phagocytosis in macrophages, with a positive modulatory role for endogenous NO and a negative regulation by exogenous LTs, likely dependent on the reduction of iNOS expression and NO production. PMID:11454666

  3. Resveratrol Induces Hepatic Mitochondrial Biogenesis Through the Sequential Activation of Nitric Oxide and Carbon Monoxide Production

    PubMed Central

    Kim, Seul-Ki; Joe, Yeonsoo; Zheng, Min; Kim, Hyo Jeong; Yu, Jae-Kyoung; Cho, Gyeong Jae; Chang, Ki Churl; Kim, Hyoung Kyu; Han, Jin; Ryter, Stefan W.

    2014-01-01

    Abstract Aims: Nitric oxide (NO) can induce mitochondrial biogenesis in cultured cells, through increased guanosine 3′,5′-monophosphate (cGMP), and activation of peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α). We sought to determine the role of NO, heme oxygenase-1 (HO-1), and its reaction product (carbon monoxide [CO]) in the induction of mitochondrial biogenesis by the natural antioxidant resveratrol. Results: S-nitroso-N-acetylpenicillamine (SNAP), an NO donor, induced mitochondrial biogenesis in HepG2 hepatoma cells, and in vivo, through stimulation of PGC-1α. NO-induced mitochondrial biogenesis required cGMP, and was mimicked by the cGMP analogue (8-bromoguanosine 3′,5′-cyclic monophosphate [8-Br-cGMP]). Activation of mitochondrial biogenesis by SNAP required HO-1, as it could be reversed by genetic interference of HO-1; and by treatment with the HO inhibitor tin-protoporphyrin-IX (SnPP) in vitro and in vivo. Cobalt protoporphyrin (CoPP)-IX, an HO-1 inducing agent, stimulated mitochondrial biogenesis in HepG2 cells, which could be reversed by the CO scavenger hemoglobin. Application of CO, using the CO-releasing molecule-3 (CORM-3), stimulated mitochondrial biogenesis in HepG2 cells, in a cGMP-dependent manner. Both CoPP and CORM-3-induced mitochondrial biogenesis required NF-E2-related factor-2 (Nrf2) activation and phosphorylation of Akt. The natural antioxidant resveratrol induced mitochondrial biogenesis in HepG2 cells, in a manner dependent on NO biosynthesis, cGMP synthesis, Nrf2-dependent HO-1 activation, and endogenous CO production. Furthermore, resveratrol preserved mitochondrial biogenesis during lipopolysaccharides-induced hepatic inflammation in vivo. Innovation and Conclusions: The complex interplay between endogenous NO and CO production may underlie the mechanism by which natural antioxidants induce mitochondrial biogenesis. Strategies aimed at improving mitochondrial biogenesis may be used as therapeutics

  4. Low concentrations of salicylic acid delay methyl jasmonate-induced leaf senescence by up-regulating nitric oxide synthase activity.

    PubMed

    Ji, Yingbin; Liu, Jian; Xing, Da

    2016-09-01

    In plants, extensive efforts have been devoted to understanding the crosstalk between salicylic acid (SA) and jasmonic acid (JA) signaling in pathogen defenses, but this crosstalk has scarcely been addressed during senescence. In this study, the effect of SA application on methyl jasmonate (MeJA)-induced leaf senescence was assessed. We found that low concentrations of SA (1-50 μM) played a delayed role against the senescence promoted by MeJA. Furthermore, low concentrations of SA enhanced plant antioxidant defenses and restricted reactive oxygen species (ROS) accumulation in MeJA-treated leaves. When applied simultaneously with MeJA, low concentrations of SA triggered a nitric oxide (NO) burst, and the elevated NO levels were linked to the nitric oxide associated 1 (NOA1)-dependent pathway via nitric oxide synthase (NOS) activity. The ability of SA to up-regulate plant antioxidant defenses, reduce ROS accumulation, and suppress leaf senescence was lost in NO-deficient Atnoa1 plants. In a converse manner, exogenous addition of NO donors increased the plant antioxidant capacity and lowered the ROS levels in MeJA-treated leaves. Taken together, the results indicate that SA at low concentrations counteracts MeJA-induced leaf senescence through NOA1-dependent NO signaling and strengthening of the antioxidant defense. PMID:27440938

  5. Overexpressed neuroglobin raises threshold for nitric oxide-induced impairment of mitochondrial respiratory activities and stress signaling in primary cortical neurons.

    PubMed

    Singh, Shilpee; Zhuo, Ming; Gorgun, Falih M; Englander, Ella W

    2013-08-01

    Surges of nitric oxide compromise mitochondrial respiration primarily by competitive inhibition of oxygen binding to cytochrome c oxidase (complex IV) and are particularly injurious in neurons, which rely on oxidative phosphorylation for all their energy needs. Here, we show that transgenic overexpression of the neuronal globin protein, neuroglobin, helps diminish protein nitration, preserve mitochondrial function and sustain ATP content of primary cortical neurons challenged by extended nitric oxide exposure. Specifically, in transgenic neurons, elevated neuroglobin curtailed nitric oxide-induced alterations in mitochondrial oxygen consumption rates, including baseline oxygen consumption, consumption coupled with ATP synthesis, proton leak and spare respiratory capacity. Concomitantly, activation of genes involved in sensing and responding to oxidative/nitrosative stress, including the early-immediate c-Fos gene and the phase II antioxidant enzyme, heme oxygenase-1, was diminished in neuroglobin-overexpressing compared to wild-type neurons. Taken together, these differences reflect a lesser insult produced by similar concentrations of nitric oxide in neuroglobin-overexpressing compared to wild-type neurons, suggesting that abundant neuroglobin buffers nitric oxide and raises the threshold of nitric oxide-mediated injury in neurons.

  6. Clonidine-induced nitric oxide-dependent vasorelaxation mediated by endothelial α2-adrenoceptor activation

    PubMed Central

    Figueroa, Xavier F; Poblete, M Inés; Boric, Mauricio P; Mendizábal, Victoria E; Adler-Graschinsky, Edda; Huidobro-Toro, J Pablo

    2001-01-01

    To assess the involvement of endothelial α2-adrenoceptors in the clonidine-induced vasodilatation, the mesenteric artery of Sprague Dawley rats was cannulated and perfused with Tyrode solution (2 ml min−1). We measured perfusion pressure, nitric oxide (NO) in the perfusate using chemiluminescence, and tissue cyclic GMP by RIA.In phenylephrine-precontracted mesenteries, clonidine elicited concentration-dependent vasodilatations associated to a rise in luminal NO. One hundred nM rauwolscine or 100 μM Lω-nitro-L-arginine antagonized the clonidine-induced vasodilatation. Guanabenz, guanfacine, and oxymetazoline mimicked the clonidine-induced vasorelaxation.In non-contracted mesenteries, 100 nM clonidine elicited a maximal rise of NO (123±13 pmol); associated to a peak in tissue cyclic GMP. Endothelium removal, Lω-nitro-L-arginine, or rauwolscine ablated the rise in NO. One hundred nM aminoclonidine, guanfacine, guanabenz, UK14,304 and oxymetazoline mimicked the clonidine-induced surge of NO. Ten μM ODQ obliterated the clonidine-induced vasorelaxation and the associated tissue cyclic GMP accumulation; 10 – 100 nM sildenafil increased tissue cyclic GMP accumulation without altering the clonidine-induced NO release.α2-Adrenergic blockers antagonized the clonidine-induced rise in NO. Consistent with a preferential α2D-adrenoceptor activation, the KBs for yohimbine, rauwolscine, phentolamine, WB-4101, and prazosin were: 6.8, 24, 19, 165, and 1489 nM, respectively.Rat pretreatment with 100 mg kg−1 6-hydroxydopamine reduced 95% tissue noradrenaline and 60% neuropeptide Y. In these preparations, 100 nM clonidine elicited a rise of 91.9±15.5 pmol NO. Perfusion with 1 μM guanethidine or 1 μM guanethidine plus 1 μM atropine did not modify the NO surge evoked by 100 nM clonidine.Clonidine and congeners activate endothelial α2D-adrenoceptors coupled to the L-arginine pathway, suggesting that the antihypertensive action of

  7. TRPV4 activation mediates flow-induced nitric oxide production in the rat thick ascending limb

    PubMed Central

    Garvin, Jeffrey L.

    2014-01-01

    Nitric oxide (NO) regulates renal function. Luminal flow stimulates NO production in the thick ascending limb (TAL). Transient receptor potential vanilloid 4 (TRPV4) is a mechano-sensitive channel activated by luminal flow in different types of cells. We hypothesized that TRPV4 mediates flow-induced NO production in the rat TAL. We measured NO production in isolated, perfused rat TALs using the fluorescent dye DAF FM. Increasing luminal flow from 0 to 20 nl/min stimulated NO from 8 ± 3 to 45 ± 12 arbitrary units (AU)/min (n = 5; P < 0.05). The TRPV4 antagonists, ruthenium red (15 μmol/l) and RN 1734 (10 μmol/l), blocked flow-induced NO production. Also, luminal flow did not increase NO production in the absence of extracellular calcium. We also studied the effect of luminal flow on NO production in TALs transduced with a TRPV4shRNA. In nontransduced TALs luminal flow increased NO production by 47 ± 17 AU/min (P < 0.05; n = 5). Similar to nontransduced TALs, luminal flow increased NO production by 39 ± 11 AU/min (P < 0.03; n = 5) in TALs transduced with a control negative sequence-shRNA while in TRPV4shRNA-transduced TALs, luminal flow did not increase NO production (Δ10 ± 15 AU/min; n = 5). We then tested the effect of two different TRPV4 agonists on NO production in the absence of luminal flow. 4α-Phorbol 12,13-didecanoate (1 μmol/l) enhanced NO production by 60 ± 11 AU/min (P < 0.002; n = 7) and GSK1016790A (10 ηmol/l) increased NO production by 52 ± 15 AU/min (P < 0.03; n = 5). GSK1016790A (10 ηmol/l) did not stimulate NO production in TRPV4shRNA-transduced TALs. We conclude that activation of TRPV4 channels mediates flow-induced NO production in the rat TAL. PMID:24966090

  8. Inhibitory effects of indole α-lipoic acid derivatives on nitric oxide production in LPS/IFNγ activated RAW 264.7 macrophages.

    PubMed

    Karabay, Arzu Zeynep; Koc, Aslı; Gurkan-Alp, A Selen; Buyukbingol, Zeliha; Buyukbingol, Erdem

    2015-04-01

    Alpha-lipoic acid (α-lipoic acid) is a potent antioxidant compound that has been shown to possess anti-inflammatory effects. RAW 264.7 macrophages produce various inflammatory mediators such as nitric oxide, IL-1β, IL-6 and TNF-alpha upon activation with LPS (Lipopolysaccharide) and IFNγ (interferon gamma). In this study, the effect of 12 synthetic indole α-lipoic acid derivatives on nitric oxide production and iNOS (inducible nitric oxide synthase) protein expression in LPS/IFNγ activated RAW 264.7 macrophages was determined. Cell proliferation, nitric oxide levels and iNOS protein expression were examined with thiazolyl blue tetrazolium blue test, griess assay and western blot, respectively. Our results showed that all of the indole α-lipoic acid derivatives showed significant inhibitory effects on nitric oxide production and iNOS protein levels (p < 0.05). The most active compounds were identified as compound I-4b, I-4e and II-3b. In conclusion, these indole α-lipoic acid derivatives may have the potential for treatment of inflammatory conditions related with high nitric oxide production.

  9. Role of phosphatase activity of soluble epoxide hydrolase in regulating simvastatin-activated endothelial nitric oxide synthase

    PubMed Central

    Hou, Hsin-Han; Liao, Yi-Jen; Hsiao, Sheng-Huang; Shyue, Song-Kun; Lee, Tzong-Shyuan

    2015-01-01

    Soluble epoxide hydrolase (sEH) has C-terminal epoxide hydrolase and N-terminal lipid phosphatase activity. Its hydrolase activity is associated with endothelial nitric oxide synthase (eNOS) dysfunction. However, little is known about the role of sEH phosphatase in regulating eNOS activity. Simvastatin, a clinical lipid-lowering drug, also has a pleiotropic effect on eNOS activation. However, whether sEH phosphatase is involved in simvastatin-activated eNOS activity remains elusive. We investigated the role of sEH phosphatase activity in simvastatin-mediated activation of eNOS in endothelial cells (ECs). Simvastain increased the phosphatase activity of sEH, which was diminished by pharmacological inhibitors of sEH phosphatase. In addition, pharmacological inhibition of sEH phosphatase or overexpressing the inactive phosphatase domain of sEH enhanced simvastatin-induced NO bioavailability, tube formation and phosphorylation of eNOS, Akt, and AMP-activated protein kinase (AMPK). In contrast, overexpressing the phosphatase domain of sEH limited the simvastatin-increased NO biosynthesis and eNOS phosphorylation at Ser1179. Simvastatin evoked epidermal growth factor receptor–c-Src–increased Tyr phosphorylation of sEH and formation of an sEH–Akt–AMPK–eNOS complex, which was abolished by the c-Src kinase inhibitor PP1 or c-Src dominant-negative mutant K298M. These findings suggest that sEH phosphatase activity negatively regulates simvastatin-activated eNOS by impeding the Akt–AMPK–eNOS signaling cascade. PMID:26304753

  10. Role of phosphatase activity of soluble epoxide hydrolase in regulating simvastatin-activated endothelial nitric oxide synthase.

    PubMed

    Hou, Hsin-Han; Liao, Yi-Jen; Hsiao, Sheng-Huang; Shyue, Song-Kun; Lee, Tzong-Shyuan

    2015-08-25

    Soluble epoxide hydrolase (sEH) has C-terminal epoxide hydrolase and N-terminal lipid phosphatase activity. Its hydrolase activity is associated with endothelial nitric oxide synthase (eNOS) dysfunction. However, little is known about the role of sEH phosphatase in regulating eNOS activity. Simvastatin, a clinical lipid-lowering drug, also has a pleiotropic effect on eNOS activation. However, whether sEH phosphatase is involved in simvastatin-activated eNOS activity remains elusive. We investigated the role of sEH phosphatase activity in simvastatin-mediated activation of eNOS in endothelial cells (ECs). Simvastain increased the phosphatase activity of sEH, which was diminished by pharmacological inhibitors of sEH phosphatase. In addition, pharmacological inhibition of sEH phosphatase or overexpressing the inactive phosphatase domain of sEH enhanced simvastatin-induced NO bioavailability, tube formation and phosphorylation of eNOS, Akt, and AMP-activated protein kinase (AMPK). In contrast, overexpressing the phosphatase domain of sEH limited the simvastatin-increased NO biosynthesis and eNOS phosphorylation at Ser1179. Simvastatin evoked epidermal growth factor receptor-c-Src-increased Tyr phosphorylation of sEH and formation of an sEH-Akt-AMPK-eNOS complex, which was abolished by the c-Src kinase inhibitor PP1 or c-Src dominant-negative mutant K298M. These findings suggest that sEH phosphatase activity negatively regulates simvastatin-activated eNOS by impeding the Akt-AMPK-eNOS signaling cascade.

  11. [A study on the activity of nitric oxide in alveolar macrophages from patients with lung cancer].

    PubMed

    Hu, C; Li, G; Wu, E

    1998-01-01

    Nitrite and nitrate (NO2-/NO2-) in the bronchus alveolar lavage fluid (BALF) and the supernatants of incubated alveolar macrophages (AMs) from patients with primary lung cancer were measured by copper-coated cadmium reduction and Griess method. Mrna expression of AM induced nitric oxide synthase (iNOS) were analyzed by RT-PCR. There was NO2-/NO2- in BALF either from lung cancer patients or from control subjects. When compared with control group and the nontumor-bearing lung, the level of NO2-/NO2-was lower in BALF from the tumor-bearing lung [5.18+/-1.1 vs 2.47+/-0.67nmol x mg protein-1 (P< 0.01); 4.65+/- 2.46 vs 2.47+/- 0.67nmol x mg protein-1(P< 0.01)]. We also found a lower level of NO2-/NO2- in the supernatants of incubated AMs from the lung of cancer patients than from control and nontumor-bearing lung [95.03+/- 21.76 vs 63.37+/- 17.58nmol (P< 0.01); 85.61+/- 16.70 vs 63.37+/- 17.58nmol (P< 0.05)]. No significant difference existed between the MRNA expression of AM iNOS in lung cancer patients (69%) and that of control subjects (91%). After the AMs were stimulated with granulocyte-macrophage colony stimulating factor (GM-CSF), the level of NO2-/NO2- in the supernatants was significantly increased (P< 0.01); while the mRNA expression of AM iNOS from patients with lung cancer resulted in an increase of 16.85+/- 7.58% vs 33.38+/- 8.21% of control group (P< 0.05). These observation suggest that some defects of antitumor function occur in the AMs at the tumor region. GM-CSF can stimulate AMs and thus potentiate their NO activity.

  12. Triterpenoic Acids from Apple Pomace Enhance the Activity of the Endothelial Nitric Oxide Synthase (eNOS).

    PubMed

    Waldbauer, Katharina; Seiringer, Günter; Nguyen, Dieu Linh; Winkler, Johannes; Blaschke, Michael; McKinnon, Ruxandra; Urban, Ernst; Ladurner, Angela; Dirsch, Verena M; Zehl, Martin; Kopp, Brigitte

    2016-01-13

    Pomace is an easy-accessible raw material for the isolation of fruit-derived compounds. Fruit consumption is associated with health-promoting effects, such as the prevention of cardiovascular disease. Increased vascular nitric oxide (NO) bioavailability, for example, due to an enhanced endothelial nitric oxide synthase (eNOS) activity, could be one molecular mechanism mediating this effect. To identify compounds from apple (Malus domestica Borkh.) pomace that have the potential to amplify NO bioavailability via eNOS activation, a bioassay-guided fractionation of the methanol/water (70:30) extract has been performed using the (14)C-L-arginine to (14)C-L-citrulline conversion assay (ACCA) in the human endothelium-derived cell line EA.hy926. Phytochemical characterization of the active fractions was performed using the spectrophotometric assessment of the total phenolic content, as well as TLC, HPLC-DAD-ELSD, and HPLC-MS analyses. Eleven triterpenoic acids, of which one is a newly discovered compound, were identified as the main constituents in the most active fraction, accompanied by only minor contents of phenolic compounds. When tested individually, none of the tested compounds exhibited significant eNOS activation. Nevertheless, cell stimulation with the reconstituted compound mixture restored eNOS activation, validating the potential of apple pomace as a source of bioactive components.

  13. Ginsenoside Rg3 increases nitric oxide production via increases in phosphorylation and expression of endothelial nitric oxide synthase: Essential roles of estrogen receptor-dependent PI3-kinase and AMP-activated protein kinase

    SciTech Connect

    Hien, Tran Thi; Kim, Nak Doo; Pokharel, Yuba Raj; Oh, Seok Jeong; Lee, Moo Yeol; Kang, Keon Wook

    2010-08-01

    We previously showed that ginsenosides increase nitric oxide (NO) production in vascular endothelium and that ginsenoside Rg3 (Rg3) is the most active one among ginseng saponins. However, the mechanism for Rg3-mediated nitric oxide production is still uncertain. In this study, we determined whether Rg3 affects phosphorylation and expression of endothelial nitric oxide synthase (eNOS) in ECV 304 human endothelial cells. Rg3 increased both the phosphorylation and the expression of eNOS in a concentration-dependent manner and a maximal effect was found at 10 {mu}g/ml of Rg3. The enzyme activities of phosphatidylinositol 3-kinase (PI3-kinase), c-Jun N-terminal kinase (JNK), and p38 kinase were enhanced as were estrogen receptor (ER)- and glucocorticoid receptor (GR)-dependent reporter gene transcriptions in Rg3-treated endothelial cells. Rg3-induced eNOS phosphorylation required the ER-mediated PI3-kinase/Akt pathway. Moreover, Rg3 activates AMP-activated protein kinase (AMPK) through up-regulation of CaM kinase II and Rg3-stimulated eNOS phosphorylation was reversed by AMPK inhibition. The present results provide a mechanism for Rg3-stimulated endothelial NO production.

  14. Nitric oxide reburning with methane

    SciTech Connect

    Kumpaty, S.K.; Subramanian, K.

    1996-12-31

    This paper deals with initial findings from the ongoing, three-year DOE program that began on 02/01/1995. The program involves computer simulation studies to aid in planning and conducting a series of experiments that will extend the knowledge of reburning process. The objective of this work is to find nitric oxide reduction effectiveness for various reburning fuels and identify both homogeneous and heterogeneous reaction mechanisms characterizing NO reduction.

  15. Effect of nitric oxide on mitochondrial activity of human synovial cells

    PubMed Central

    2011-01-01

    Background Nitric oxide (NO) is a messenger implicated in the destruction and inflammation of joint tissues. Cartilage and synovial membrane from patients with rheumatoid arthritis (RA) and osteoarthritis (OA) have high levels of NO. NO is known to modulate various cellular pathways and, thus, inhibit the activity of the mitochondrial respiratory chain (MRC) of chondrocytes and induce the generation of reactive oxygen species (ROS) and cell death in multiple cell types. For these reasons, and because of the importance of the synovial membrane in development of OA pathology, we investigated the effects of NO on survival, mitochondrial function, and activity of fibroblastic human OA synovial cells. Methods Human OA synovia were obtained from eight patients undergoing hip joint replacement. Sodium nitroprusside (SNP) was used as a NO donor compound and cell viability was evaluated by MTT assays. Mitochondrial function was evaluated by analyzing the mitochondrial membrane potential (Δψm) with flow cytometry using the fluorofore DePsipher. ATP levels were measured by luminescence assays, and the activities of the respiratory chain complexes (complex I: NADH CoQ1 reductase, complex II: succinate dehydrogenase, complex III: ubiquinol-cytochrome c reductase, complex IV: cytochrome c oxidase) and citrate synthase (CS) were measured by enzymatic assay. Protein expression analyses were performed by western blot. Results SNP at a concentration of 0.5 mM induced cell death, shown by the MTT method at different time points. The percentages of viable cells at 24, 48 and 72 hours were 86.11 ± 4.9%, 74.31 ± 3.35%, and 43.88 ± 1.43%, respectively, compared to the basal level of 100% (*p < 0.05). SNP at 0.5 mM induced depolarization of the mitochondrial membrane at 12 hours with a decrease in the ratio of polarized cells (basal = 2.48 ± 0.28; SNP 0.5 mM = 1.57 ± 0.11; *p < 0.01). The time course analyses of treatment with SNP at 0.5 mM demonstrated that treatment reliably and

  16. AMP-activated protein kinase (AMPK) regulates the insulin-induced activation of the nitric oxide synthase in human platelets.

    PubMed

    Fleming, Ingrid; Schulz, Christian; Fichtlscherer, Birgit; Kemp, Bruce E; Fisslthaler, Beate; Busse, Rudi

    2003-11-01

    Little is known about the signaling cascades that eventually regulate the activity of the endothelial nitric oxide synthase (eNOS) in platelets. Here, we investigated the effects of insulin on the phosphorylation and activation of eNOS in washed human platelets and in endothelial cells. Insulin activated the protein kinase Akt in cultured endothelial cells and increased the phosphorylation of eNOS on Ser(1177) but failed to increase endothelial cyclic GMP levels or to elicit the relaxation of endothelium-intact porcine coronary arteries. In platelets, insulin also elicited the activation of Akt as well as the phosphorylation of eNOS and initiated NO production which was associated with increased cyclic GMP levels and the inhibition of thrombin-induced aggregation. The insulin-induced inhibition of aggregation was accompanied by a decreased Ca(2+) response to thrombin and was also prevented by N(omega) nitro-L-arginine. In platelets, but not in endothelial cells, insulin induced the activation of the AMP-activated protein kinase (AMPK), a metabolic stress-sensing kinase which was sensitive to the phosphatidylinositol 3-kinase (PI3-K) inhibitor wortmannin and the AMPK inhibitor iodotubercidin. Moreover, the insulin-mediated inhibition of thrombin-induced aggregation was prevented by iodotubercidin. Insulin-independent activation of the AMPK using 5-aminoimidazole-4-carboxamide ribonucleoside, increased platelet eNOS phosphorylation, increased cyclic GMP levels and attenuated platelet aggregation. These results highlight the differences in the signal transduction cascade activated by insulin in endothelial cells and platelets, and demonstrate that insulin stimulates the formation of NO in human platelets, in the absence of an increase in Ca(2+), by acti-vating PI3-K and AMPK which phosphorylates eNOS on Ser(1177).

  17. A Comparison of the Effects of Neuronal Nitric Oxide Synthase and Inducible Nitric Oxide Synthase Inhibition on Cartilage Damage

    PubMed Central

    Gokay, Nevzat Selim; Yilmaz, Ibrahim; Demiroz, Ahu Senem; Gokce, Alper; Dervisoglu, Sergülen; Gokay, Banu Vural

    2016-01-01

    The objective of this study was to investigate the effects of selective inducible nitric oxide synthase and neuronal nitric oxide synthase inhibitors on cartilage regeneration. The study involved 27 Wistar rats that were divided into five groups. On Day 1, both knees of 3 rats were resected and placed in a formalin solution as a control group. The remaining 24 rats were separated into 4 groups, and their right knees were surgically damaged. Depending on the groups, the rats were injected with intra-articular normal saline solution, neuronal nitric oxide synthase inhibitor 7-nitroindazole (50 mg/kg), inducible nitric oxide synthase inhibitor amino-guanidine (30 mg/kg), or nitric oxide precursor L-arginine (200 mg/kg). After 21 days, the right and left knees of the rats were resected and placed in formalin solution. The samples were histopathologically examined by a blinded evaluator and scored on 8 parameters. Although selective neuronal nitric oxide synthase inhibition exhibited significant (P = 0.044) positive effects on cartilage regeneration following cartilage damage, it was determined that inducible nitric oxide synthase inhibition had no statistically significant effect on cartilage regeneration. It was observed that the nitric oxide synthase activation triggered advanced arthrosis symptoms, such as osteophyte formation. The fact that selective neuronal nitric oxide synthase inhibitors were observed to have mitigating effects on the severity of the damage may, in the future, influence the development of new agents to be used in the treatment of cartilage disorders. PMID:27382570

  18. Inhibition of nitric oxide production in lipopolysaccharide-activated RAW 264.7 macrophages by Jeju plant extracts

    PubMed Central

    Yang, Eun-Jin; Yim, Eun-Young; Song, Gwanpil; Kim, Gi-Ok; Hyun, Chang-Gu

    2009-01-01

    Nitric oxide (NO) produced in large amounts by inducible nitric oxide synthase (iNOS) is known to be responsible for the vasodilation and hypotension observed during septic shock and inflammation. Thus, inhibitors of iNOS may be useful candidates for the treatment of inflammatory diseases accompanied by the overproduction of NO. In this study, we prepared alcoholic extracts of Jeju plants and screened them for their inhibitory activity against NO production in lipopolysaccharide (LPS)-activated macrophages. Among the 260 kinds of plant extract tested, 122 extracts showed potent inhibitory activity towards NO production by more than 25% at a concentration of 100 µg/mL. Plants such as Malus sieboldii, Vaccinium oldhamii, Corylus hallaisanensis, Carpinus laxiflora, Styrax obassia, and Securinega suffruticosa showed the most potent inhibition (above 70%) at a concentration of 100 µg/mL. The cytotoxic effects of the plant extracts were determined by colorimetric MTT assays and most plant extracts exhibited only moderate cytotoxicity at 100 µg/mL. Therefore, these plants should be considered promising candidates for the further purification of bioactive compounds and would be useful for the treatment of inflammatory diseases accompanying overproduction of NO. PMID:21217861

  19. Chitosan and blueberry treatment induces arginase activity and inhibits nitric oxide production during acetaminophen-induced hepatotoxicity

    PubMed Central

    Ozcelik, Eda; Uslu, Sema; Burukoglu, Dilek; Musmul, Ahmet

    2014-01-01

    Background: Liver diseases have become a major problem of the worldwide. More than 50% of all cases of liver failure can be attributed to drugs. Among these, acetaminophen is the most common cause. Objective: The aim of this study was to investigate the the hepatoprotective effects of blueberry and chitosan on tissue arginase activity, ornithine and nitric oxide levels during the acetaminophen-induced hepatotoxicity. Materials and Methods: Acetaminophen (250 mg/kg body weight per day), blueberry (60 mg/kg body weight per day) and, chitosan (200 mg/kg body weight per day) were administered to the rats by oral gavage during the experimental period. Results: Blueberry and chitosan significantly decreased liver arginase activity and ornithine levelsand and increased nitric oxide levels. Glutathione levels were remarkably increased by chitosan and blueberry treatments. Conclusion: The results of the present study indicate that blueberry and chitosan effectively protected against the acetaminophen-induced hepatotoxicity. The hepatoprotective effect afforded by blueberry and chitosan can be attributed to its antioxidant and anti-inflammatory activities. PMID:24991095

  20. Interplay between mitogen-activated protein kinase and nitric oxide in brassinosteroid-induced pesticide metabolism in Solanum lycopersicum.

    PubMed

    Yin, Yan-Ling; Zhou, Yue; Zhou, Yan-Hong; Shi, Kai; Zhou, Jie; Yu, Yunlong; Yu, Jing-Quan; Xia, Xiao-Jian

    2016-10-01

    Nitric oxide (NO) and mitogen-activated protein kinase (MPK) play important roles in brassinosteroid (BR)-induced stress tolerance, however, their functions in BR-induced pesticides metabolism remain unclear. Here, we showed that MPK activity and transcripts of SlMPK1 and SlMPK2 were induced by chlorothalonil (CHT), a widely used fungicide, in tomato leaves. However, cosilencing of SlMPK1/2 compromised the 24-epibrassinolide (EBR)-induced upregulation of detoxification genes and CHT metabolism in tomato leaves. In addition, cosilencing of SlMPK1/2 inhibited the accumulation of S-nitrosothiol (SNO), the reservoir of nitric oxide (NO) in plants, whereas tungstate, the inhibitor of nitrate reductase (NR), blocked EBR-induced SNO accumulation and MPK activity. Inhibiting the accumulation of NO by cPTIO, the specific scavenger and tungstate abolished the EBR-induced upregulation of detoxification genes, glutathione accumulation and CHT metabolism. The results showed that MPK and NR-dependent NO were involved in BR-induced CHT metabolism. Notably, there was a positive crosstalk between the MPK and NO production. PMID:27236431

  1. Median eminence nitric oxide signaling.

    PubMed

    Prevot, V; Bouret, S; Stefano, G B; Beauvillain, J

    2000-11-01

    It is becoming increasingly clear that nitric oxide (NO), an active free radical formed during the conversion of arginine to citrulline by the enzyme NO synthase (NOS), is a critical neurotransmitter and biological mediator of the neuroendocrine axis. Current evidence suggests that NO modulates the activity of both the hypothalamic-pituitary-gonadal axis and the hypothalamic-pituitary-adrenal axis. Supporting this hypothesis is the finding that the highest expression of neuronal NOS in the brain is found within the hypothalamus in areas where the cell bodies of the neurons from the different neuroendocrine systems are located. In this regard, the influence of neuronal NO on the regulation of the neuroendocrine neural cell body activity has been well-documented whereas little is known about NO signaling that directly modulates neurohormonal release into the pituitary portal vessels from the neuroendocrine terminals within the median eminence, the common termination field of the adenohypophysiotropic systems. Studies in rat suggest that NO is an important factor controlling both gonadotropin-releasing hormone (GnRH) and corticotropin-releasing hormone (CRH) release at the median eminence. The recent use of amperometric NO detection from median eminence fragments coupled to the use of selective NOS inhibitors demonstrated that a major source of NO at the median eminence might be endothelial in origin rather than neuronal. The present article reviews the recent progress in identifying the origin and the role of the NO produced at the median eminence in the control of neurohormonal release. We also discuss the potential implications of the putative involvement of the median eminence endothelial cells in a neurovascular regulatory process for hypothalamic neurohormonal signaling.

  2. Use-dependent loss of active sympathetic neurogenic vasodilation after nitric oxide synthase inhibition in conscious rats. Evidence for the presence of preformed stores of nitric oxide-containing factors

    NASA Technical Reports Server (NTRS)

    Davisson, R. L.; Shaffer, R. A.; Johnson, A. K.; Lewis, S. J.

    1996-01-01

    In this study, we examined whether air-jet stress-induced active sympathetic hindlimb vasodilation in conscious rats involves the release of preformed stores of nitric oxide-containing factors. We determined the effects of repeated episodes of air-jet stress (six episodes given 5 minutes apart) on mean arterial pressure and vascular resistances in the mesenteric bed and intact and sympathetically denervated hindlimb beds of conscious rats treated with saline or the nitric oxide synthesis inhibitor N omega-nitro-L-arginine methyl ester (L-NAME, 25 mumol/kg IV). In saline-treated rats, air-jet stress produced alerting behavior, minor changes in blood pressure, pronounced mesenteric vaso-constriction, and immediate and marked vasodilation in the sympathetically intact hindlimb but a minor vasodilation in the sympathetically denervated hindlimb. Each air-jet stress produced virtually identical responses. In L-NAME-treated rats, the first air-jet stress produced vasodilator responses in the sympathetically intact and sympathetically denervated hindlimbs that were similar to those in the saline-treated rats. However, each subsequent air-jet stress produced progressively smaller vasodilator responses in the sympathetically intact but not the sympathetically denervated hindlimb. There was no loss of air-jet stress-induced alerting behavior or mesenteric vasoconstriction, suggesting that L-NAME did not interfere with the central processing of the air-jet or the resultant changes in autonomic nerve activity. The progressive diminution of air-jet stress-induced vasodilation in the intact hindlimb of L-NAME-treated rats may be due to the use-dependent depletion of preformed stores of nitric oxide-containing factors that cannot be replenished in the absence of nitric oxide synthesis.

  3. Variation of D-region nitric-oxide density with solar activity and season at the dip equator

    NASA Technical Reports Server (NTRS)

    Chakrabarty, D. K.; Pakhomov, S. V.; Beig, G.

    1989-01-01

    To study the solar control on electron density (N sub e) in the equatorial D region, a program was initiated with Soviet collaboration in 1979. A total of 31 rockets were launched during the high solar activity period, and 47 rockets during the low solar activity period, from Thumba to measure the N sub e profiles. Analysis of the data shows that the average values of N sub e for the high solar activity period are higher by a factor of about 2 to 3 compared to the low solar activity values. It was found that a single nitric oxide density, (NO), profile cannot reproduce all the observed N sub e profiles. An attempt was made to reproduce theoretically the observed N sub e profiles by introducing variation in (NO) for the different solar activity periods and seasons.

  4. The Effect of Anandamide on Uterine Nitric Oxide Synthase Activity Depends on the Presence of the Blastocyst

    PubMed Central

    Sordelli, Micaela S.; Beltrame, Jimena S.; Burdet, Juliana; Zotta, Elsa; Pardo, Romina; Cella, Maximiliano; Franchi, Ana M.; Ribeiro, Maria Laura

    2011-01-01

    Nitric oxide production, catalyzed by nitric oxide synthase (NOS), should be strictly regulated to allow embryo implantation. Thus, our first aim was to study NOS activity during peri-implantation in the rat uterus. Day 6 inter-implantation sites showed lower NOS activity (0.19±0.01 pmoles L-citrulline mg prot−1 h−1) compared to days 4 (0.34±0.03) and 5 (0.35±0.02) of pregnancy and to day 6 implantation sites (0.33±0.01). This regulation was not observed in pseudopregnancy. Both dormant and active blastocysts maintained NOS activity at similar levels. Anandamide (AEA), an endocannabinoid, binds to cannabinoid receptors type 1 (CB1) and type 2 (CB2), and high concentrations are toxic for implantation and embryo development. Previously, we observed that AEA synthesis presents an inverted pattern compared to NOS activity described here. We adopted a pharmacological approach using AEA, URB-597 (a selective inhibitor of fatty acid amide hydrolase, the enzyme that degrades AEA) and receptor selective antagonists to investigate the effect of AEA on uterine NOS activity in vitro in rat models of implantation. While AEA (0.70±0.02 vs 0.40±0.04) and URB-597 (1.08±0.09 vs 0.83±0.06) inhibited NOS activity in the absence of a blastocyst (pseudopregnancy) through CB2 receptors, AEA did not modulate NOS on day 5 pregnant uterus. Once implantation begins, URB-597 decreased NOS activity on day 6 implantation sites via CB1 receptors (0.25±0.04 vs 0.40±0.05). While a CB1 antagonist augmented NOS activity on day 6 inter-implantation sites (0.17±0.02 vs 0.27±0.02), a CB2 antagonist decreased it (0.17±0.02 vs 0.12±0.01). Finally, we described the expression and localization of cannabinoid receptors during implantation. In conclusion, AEA levels close to and at implantation sites seems to modulate NOS activity and thus nitric oxide production, fundamental for implantation, via cannabinoid receptors. This modulation depends on the presence of the blastocyst. These data

  5. N-Methyl-d-Aspartate Receptor and Neuronal Nitric Oxide Synthase Activation Mediate Bilirubin-Induced Neurotoxicity

    PubMed Central

    Brito, Maria A; Vaz, Ana R; Silva, Sandra L; Falcão, Ana S; Fernandes, Adelaide; Silva, Rui FM; Brites, Dora

    2010-01-01

    Hyperbilirubinemia may lead to neurotoxicity and neuronal death. Although the mechanisms of nerve cell damage by unconjugated bilirubin (UCB) appear to involve a disruption of the redox status and excitotoxicity, the contribution of nitric oxide (NO·) and of N-methyl-d-aspartate (NMDA) glutamate receptors is unclear. We investigated the role of NO· and NMDA glutamate receptors in the pathways of nerve cell demise by UCB. Neurons were incubated with 100 μmol/L UCB, in the presence of 100 μmol/L human serum albumin for 4 h at 37ºC, alone or in combination with N-ω-nitro-l-arginine methyl ester (l-NAME) (an inhibitor of neuronal nitric oxide synthase [nNOS]), hemoglobin (an NO· scavenger) or (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801) (an NMDA-receptor antagonist). Exposure to UCB led to increased expression of nNOS and production of both NO· and cyclic guanosine 3′,5′-monophosphate (cGMP), along with protein oxidation and depletion of glutathione. These events concurred for cell dysfunction and death and were counteracted by l-NAME. Moreover, the UCB-induced loss of neuronal viability was abolished by hemoglobin, whereas the activation of nNOS and production of both NO· and cGMP were counteracted by MK-801, resulting in significant protection from cell dysfunction and death. These results reinforce the involvement of oxidative stress by showing that nerve cell damage by UCB is mediated by NO· and therefore is counteracted by NO· inhibitors or scavengers. Our findings strongly suggest that the activation of nNOS and neurotoxicity occur through the engagement of NMDA receptors. These data reveal a role for overstimulation of glutamate receptors in mediating oxidative damage by UCB. PMID:20593111

  6. AMP-activated protein kinase and nitric oxide regulate the glucose sensitivity of ventromedial hypothalamic glucose-inhibited neurons.

    PubMed

    Murphy, Beth Ann; Fakira, Kurt A; Song, Zhentao; Beuve, Annie; Routh, Vanessa H

    2009-09-01

    The mechanisms by which glucose regulates the activity of glucose-inhibited (GI) neurons in the ventromedial hypothalamus (VMH) are largely unknown. We have previously shown that AMP-activated protein kinase (AMPK) increases nitric oxide (NO) production in VMH GI neurons. We hypothesized that AMPK-mediated NO signaling is required for depolarization of VMH GI neurons in response to decreased glucose. In support of our hypothesis, inhibition of neuronal nitric oxide synthase (nNOS) or the NO receptor soluble guanylyl cyclase (sGC) blocked depolarization of GI neurons to decreased glucose from 2.5 to 0.7 mM or to AMPK activation. Conversely, activation of sGC or the cell-permeable analog of cGMP, 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP), enhanced the response of GI neurons to decreased glucose, suggesting that stimulation of NO-sGC-cGMP signaling by AMPK is required for glucose sensing in GI neurons. Interestingly, the AMPK inhibitor compound C completely blocked the effect of sGC activation or 8-Br-cGMP, and 8-Br-cGMP increased VMH AMPKalpha2 phosphorylation. These data suggest that NO, in turn, amplifies AMPK activation in GI neurons. Finally, inhibition of the cystic fibrosis transmembrane regulator (CFTR) Cl(-) conductance blocked depolarization of GI neurons to decreased glucose or AMPK activation, whereas decreased glucose, AMPK activation, and 8-Br-cGMP increased VMH CFTR phosphorylation. We conclude that decreased glucose triggers the following sequence of events leading to depolarization in VMH GI neurons: AMPK activation, nNOS phosphorylation, NO production, and stimulation of sGC-cGMP signaling, which amplifies AMPK activation and leads to closure of the CFTR. PMID:19570894

  7. Polyphenols from the stems of Morus alba and their inhibitory activity against nitric oxide production by lipopolysaccharide-activated microglia.

    PubMed

    Rivière, Céline; Krisa, Stéphanie; Péchamat, Laurent; Nassra, Merian; Delaunay, Jean-Claude; Marchal, Axel; Badoc, Alain; Waffo-Téguo, Pierre; Mérillon, Jean-Michel

    2014-09-01

    Neuroinflammatory processes are involved in the pathogenesis of many neurodegenerative disorders. Microglial cells, the main immune cells of the central nervous system, represent a target of interest to search for naturally occurring anti-inflammatory products. In this study, we evaluated the anti-inflammatory properties of polyphenols obtained from the stems of Morus alba. This edible species, known as white mulberry, is frequently studied because of its traditional use in Asian medicine and its richness in different types of polyphenols, some of which are known to be phytoalexins. One new coumarin glycoside, isoscopoletin 6-(6-O-β-apiofuranosyl-β-glucopyranoside) (1) was mainly isolated by CPC (centrifugal partition chromatography) from this plant, together with seven known polyphenols (2-8). Their structures were established on the basis of spectroscopic analyses including extensive 2D NMR studies. The eight isolated compounds were evaluated for their inhibitory activities on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 microglial cells. The absence of cell toxicity is checked by a MTT assay.

  8. Binding of nitrite and its reductive activation to nitric oxide at biomimetic copper centers.

    PubMed

    Monzani, E; Anthony, G J; Koolhaas, A; Spandre, A; Leggieri, E; Casella, L; Gullotti, M; Nardin, G; Randaccio, L; Fontani, M; Zanello, P; Reedijk, J

    2000-04-01

    analyzed. The mechanism of reductive activation of nitrite to nitric oxide by the Cu(I) complexes of 1-bb, 2-bb, and ddah has been studied. The reaction requires two protons per molecule of nitrite and Cu(I). Kinetic experiments show that the reaction is first order in [Cu(I)] and [H+] and exhibits saturation behavior with respect to nitrite concentration. The kinetic data show that [Cu(2-bb)]+ is more efficient than [Cu(1-bb)]+ and [Cu(ddah)]+ in reducing nitrite. PMID:10819470

  9. Evaluation of antibacterial activity of nitric oxide-releasing polymeric particles against Staphylococcus aureus and Escherichia coli from bovine mastitis.

    PubMed

    Cardozo, Viviane F; Lancheros, Cesar A C; Narciso, Adélia M; Valereto, Elaine C S; Kobayashi, Renata K T; Seabra, Amedea B; Nakazato, Gerson

    2014-10-01

    Bovine mastitis is a serious veterinary disease that causes great loss to the dairy industry worldwide. It is a major infectious disease and is difficult to manage and control. Furthermore, emerging multidrug resistant bacteria that cause mastitis have complicated such management. The free radical nitric oxide (NO) is a potent antimicrobial agent. Thus, the aims of this study were to prepare and evaluate the antibacterial activity of nitric oxide-releasing polymeric particles against Staphylococcus aureus (MBSA) and Escherichia coli (MBEC), which were isolated from bovine mastitis. Fifteen MBSA isolates and fifteen MBEC were collected from subclinical and clinical bovine mastitis. Biocompatible polymeric particles composed of alginate/chitosan or chitosan/sodium tripolyphosphate (TPP) were prepared and used to encapsulate mercaptosuccinic acid (MSA), which is a thiol-containing molecule. Nitrosation of thiol groups of MSA-containing particles formed S-nitroso-MSA particles, which are NO donors. The NO release kinetics from the S-nitroso-MSA particles showed sustained and controlled NO release over several hours. The antibacterial activity of NO-releasing particles was evaluated by incubating the particles with an MBSA multi-resistant strain, which is responsible for bovine mastitis. The minimum inhibitory concentration for S-nitroso-MSA-alginate/chitosan particles against MBSA ranged from 125 μg/mL to 250 μg/mL. The results indicate that NO-releasing polymeric particles are an interesting approach to combating bacteria resistance in bovine mastitis treatment and prevention.

  10. Nitric oxide in marine photosynthetic organisms.

    PubMed

    Kumar, Amit; Castellano, Immacolata; Patti, Francesco Paolo; Palumbo, Anna; Buia, Maria Cristina

    2015-05-01

    Nitric oxide is a versatile and powerful signaling molecule in plants. However, most of our understanding stems from studies on terrestrial plants and very little is known about marine autotrophs. This review summarizes current knowledge about the source of nitric oxide synthesis in marine photosynthetic organisms and its role in various physiological processes under normal and stress conditions. The interactions of nitric oxide with other stress signals and cross talk among secondary messengers are also highlighted.

  11. Release of nitric oxide during the T cell-independent pathway of macrophage activation

    SciTech Connect

    Beckerman, K.P.; Rogers, H.W.; Corbett, J.A.; Schreiber, R.D.; McDaniel, M.L.; Unanue, E.R. )

    1993-02-01

    Immunodeficient mice are remarkably resistant to Listeria monocytogenes (LM) infection. The authors examined the role that nitric oxide (NO) plays in the CB-17/lcr SCID (SCID) response to LM. SCID spleen cells produced large quantities of NO (as measured by nitrite formation) when incubated in the presence of heat-killed LM. NO produced large quantities of nitrite in response to LM, but only in the presence of IFN-[gamma]. The production of NO induced by LM was not affected by neutralizing antibodies to TNF or IL-1. The production of NO was inhibited by addition of either of two inhibitors of NO synthase, N[sup G]-monomethyl arginine, or aminoguanidine. In a different situation, NK cells that were stimulated by TNF and Listeria products to release IFN-[gamma] did not produce NO. Macrophages cultured with IFN-[gamma] killed live LM. This increased killing of LM was significantly inhibited by amino-guanidine. In vivo, administration of aminoguanidine resulted in a marked increase in the mortality and spleen bacterial loads of LM-infected SCID or immunocompetent control mice. It is concluded that NO is a critical effector molecule of T cell-independent natural resistence of LM as studied in the SCID mouse, and that the NO-mediated response is essential for both SCID and immunocompetent host to survive after LM infection. 37 refs., 7 figs.

  12. Novel effects of nitric oxide

    NASA Technical Reports Server (NTRS)

    Davis, K. L.; Martin, E.; Turko, I. V.; Murad, F.

    2001-01-01

    Nitric oxide (NO), a simple free radical gas, elicits a surprisingly wide range of physiological and pathophysiological effects. NO interacts with soluble guanylate cyclase to evoke many of these effects. However, NO can also interact with molecular oxygen and superoxide radicals to produce reactive nitrogen species that can modify a number of macromolecules including proteins, lipids, and nucleic acids. NO can also interact directly with transition metals. Here, we have reviewed the non--3',5'-cyclic-guanosine-monophosphate-mediated effects of NO including modifications of proteins, lipids, and nucleic acids.

  13. Involvement of Nitric Oxide on Calcium Mobilization and Arachidonic Acid Pathway Activation during Platelet Aggregation with different aggregating agonists

    PubMed Central

    Banerjee, Debipriya; Mazumder, Sahana; Kumar Sinha, Asru

    2016-01-01

    Platelet aggregation by different aggregating agonists is essential in the normal blood coagulation process, the excess of which caused acute coronary syndrome (ACS). In all cases, the activation of arachidonic acid by cycloxygenase was needed for the synthesis of thromboxane A2 (TXA2) but the mechanism of arachidonic acid release in platelets remains obscure. Studies were conducted to determine the role of nitric oxide (NO), if any, on the release of arachidonic acid in platelets. The cytosolic Ca2+ was visualized and quantitated by fluorescent spectroscopy by using QUIN-2. NO was measured by methemoglobin method. Arachidonic acid was determined by HPLC. TXA2 was measured as ThromboxaneB2 (TXB2) by ELISA. Treatment of platelets in platelet-rich plasma (PRP) with different aggregating agents resulted in the inhibition of nitric oxide synthase (NOS) which inhibited the production of NO synthesis and increased TXA2 synthesis. Furthermore, the treatment of washed PRP with different platelet aggregating agents resulted in the increase of [Ca2+] in nM ranges. In contrast, the pre-treatment of washed PRP with aspirin increased platelet NO level and inhibited the Ca2+ mobilization and TXA2 synthesis. These results indicated that the aggregation of platelets by different aggregating agonists was caused by the cytosolic Ca2+ mobilization due to the inhibition of NOS. PMID:27127451

  14. Vascular oxidative stress, nitric oxide and atherosclerosis.

    PubMed

    Li, Huige; Horke, Sven; Förstermann, Ulrich

    2014-11-01

    In the vascular wall, reactive oxygen species (ROS) are produced by several enzyme systems including NADPH oxidase, xanthine oxidase, uncoupled endothelial nitric oxide synthase (eNOS) and the mitochondrial electron transport chain. On the other hand, the vasculature is protected by antioxidant enzyme systems, including superoxide dismutases, catalase, glutathione peroxidases and paraoxonases, which detoxify ROS. Cardiovascular risk factors such as hypercholesterolemia, hypertension, and diabetes mellitus enhance ROS generation, resulting in oxidative stress. This leads to oxidative modification of lipoproteins and phospholipids, mechanisms that contribute to atherogenesis. In addition, oxidation of tetrahydrobiopterin may cause eNOS uncoupling and thus potentiation of oxidative stress and reduction of eNOS-derived NO, which is a protective principle in the vasculature. This review summarizes the latest advances in the role of ROS-producing enzymes, antioxidative enzymes as well as NO synthases in the initiation and development of atherosclerosis.

  15. Phenylephrine activates eNOS Ser 1177 phosphorylation and nitric oxide signaling in renal hypertensive rat aorta.

    PubMed

    Silva, Bruno R; Pernomian, Laena; Grando, Marcella D; Bendhack, Lusiane M

    2014-09-01

    The endothelial nitric oxide synthase (eNOS) plays an important role in the control of the vascular tone. This work aimed to evaluate the role of an α1-adrenoceptor agonist phenylephrine (PE) on eNOS activity and downstream signaling pathway activation in normotensive (2K) and renal hypertensive (2K-1C) intact-endothelium rat aortas. Concentration-effect curves were performed for PE in intact-endothelium aortas from 2K and 2K-1C rats, in the absence of or in the presence of NOS or soluble guanylyl cyclase (sGC) inhibitor. Intact endothelium aortas were stimulated with PE in organ chambers and eNOS Ser(1177)/Thr(495) phosphorylation expression was evaluated by western blot. Nitric Oxide (NO) production was evaluated in isolated endothelial cells from 2K and 2K-1C rat aortas by flow-cytometry using NO selective fluorescent probe, DAF-2DA. The sGC activity/expression was also evaluated. PE-induced contractile response is lower in 2K-1C than in 2K intact-endothelium rat aorta. This is due to higher eNOS Ser(1177) phosphorylation in 2K-1C, which induces the eNOS overactivation. It was abolished by NOS or sGC inhibition. Phenylephrine reduces NO production in 2K as compared to the basal level, but it is not modified in 2K-1C. In PE-stimulated endothelial cells, the NO production is higher in 2K-1C than in 2K. Phenylephrine induces higher cGMP production in 2K-1C than in 2K, despite the lower expression of sGC in 2K-1C. Our results suggest that alpha1-adrenoceptor activation contributes to the increased activity of the enzyme eNOS by Ser(1177) phosphorylation in 2K-1C intact-endothelium aorta, which consequently decreases PE-induced contractile response.

  16. Inducible Nitric Oxide Synthase Deficiency Impairs Matrix Metalloproteinase-9 Activity and Disrupts Leukocyte Migration in Hepatic Ischemia/Reperfusion Injury

    PubMed Central

    Hamada, Takashi; Duarte, Sergio; Tsuchihashi, Seiichiro; Busuttil, Ronald W.; Coito, Ana J.

    2009-01-01

    Matrix metalloproteinase 9 (MMP-9) is a critical mediator of leukocyte migration in hepatic ischemia/reperfusion (I/R) injury. To test the relevance of inducible nitric oxide synthase (iNOS) expression on the regulation of MMP-9 activity in liver I/R injury, our experiments included both iNOS-deficient mice and mice treated with ONO-1714, a specific iNOS inhibitor. The inability of iNOS-deficient mice to generate iNOS-derived nitric oxide (NO) profoundly inhibited MMP-9 activity and depressed leukocyte migration in livers after I/R injury. While macrophages expressed both iNOS and MMP-9 in damaged wild-type livers, neutrophils expressed MMP-9 and were virtually negative for iNOS; however, exposure of isolated murine neutrophils and macrophages to exogenous NO increased MMP-9 activity in both cell types, suggesting that NO may activate MMP-9 in leukocytes by either autocrine or paracrine mechanisms. Furthermore, macrophage NO production through the induction of iNOS was capable of promoting neutrophil transmigration across fibronectin in a MMP-9-dependent manner. iNOS expression in liver I/R injury was also linked to liver apoptosis, which was reduced in the absence of MMP-9. These results suggest that MMP-9 activity induced by iNOS-derived NO may also lead to detachment of hepatocytes from the extracellular matrix and cell death, in addition to regulating leukocyte migration across extracellular matrix barriers. These data provide evidence for a novel mechanism by which MMP-9 can mediate iNOS-induced liver I/R injury. PMID:19443702

  17. Granulocytic Myeloid Derived Suppressor Cells Expansion during Active Pulmonary Tuberculosis Is Associated with High Nitric Oxide Plasma Level

    PubMed Central

    El Daker, Sary; Sacchi, Alessandra; Tempestilli, Massimo; Carducci, Claudia; Goletti, Delia; Vanini, Valentina; Colizzi, Vittorio; Lauria, Francesco Nicola; Martini, Federico; Martino, Angelo

    2015-01-01

    Tuberculosis (TB) is still the principal cause of death caused by a single infectious agent, and the balance between the bacillus and host defense mechanisms reflects the different manifestations of the pathology. The aim of this work was to study the role of myeloid-derived suppressor cells (MDSCs) during active pulmonary tuberculosis at the site of infection. We observed an expansion of MDSCs in the lung and blood of patients with active TB, which are correlated with an enhanced amount of nitric oxide in the plasma. We also found that these cells have the remarkable ability to suppress T-cell response, suggesting an important role in the modulation of the immune response against TB. Interestingly, a trend in the diminution of MDSCs was found after an efficacious anti-TB therapy, suggesting that these cells may be used as a potential biomarker for monitoring anti-TB therapy efficacy. PMID:25879532

  18. Cadinane sesquiterpenes from Curcuma phaeocaulis with their inhibitory activities on nitric oxide production in RAW 264.7 cells.

    PubMed

    Ma, Jianghao; Wang, Ying; Liu, Yue; Gao, Suyu; Ding, Liqin; Zhao, Feng; Chen, Lixia; Qiu, Feng

    2015-06-01

    Four new cadinane-type sesquiterpenes named phacadinanes A-D (1-4) were isolated from the rhizomes of Curcuma phaeocaulis. Their structures were elucidated by 1D and 2D NMR, as well as accurate mass measurements. Compound 4 was the first example of a rare 4,5-seco-cadinane sesquiterpene isolated from the Zingiberaceae family. Furthermore, inhibitory effects of the isolated compounds on nitric oxide production in LPS-activated macrophages were evaluated. Compounds 1 and 2 showed strong inhibitory activities on NO production with IC50 values of 3.88±0.58 and 2.25±0.71 μM, respectively. A possible biogenetic pathway for 4,5-seco-cadinane sesquiterpene (4) was postulated.

  19. Prenylated flavonoids from the heartwood of Artocarpus communis with inhibitory activity on lipopolysaccharide-induced nitric oxide production.

    PubMed

    Han, Ah-Reum; Kang, You-Jin; Windono, Tri; Lee, Sang Kook; Seo, Eun-Kyoung

    2006-04-01

    A new prenylated chalcone, 3' ',3' '-dimethylpyrano[3',4']2,4,2'-trihydroxychalcone (1), was isolated from the heartwood of Artocarpus communis. Two flavonoid derivatives, (-)-cycloartocarpin (9) and (-)-cudraflavone A (10), were isolated as new isomers. In addition, eight known flavonoids, isobacachalcone (2), morachalcone A (3), gemichalcones B (4) and C (5), artocarpin (6), cudraflavone C (7), licoflavone C (8), and (2S)-euchrenone a(7) (11), were isolated and identified from this plant for the first time. Compounds 1-4, 6, and 11 exhibited potent inhibitory activity on nitric oxide production in RAW264.7 LPS-activated mouse macrophage cells with IC(50) values of 18.8, 6.4, 16.4, 9.3, 18.7, and 12.3 microM, respectively. The structure of compound 1 was elucidated by spectroscopic data analysis, including 1D and 2D NMR experiments.

  20. Nitric oxide activity in the human coronary circulation. Impact of risk factors for coronary atherosclerosis.

    PubMed Central

    Quyyumi, A A; Dakak, N; Andrews, N P; Husain, S; Arora, S; Gilligan, D M; Panza, J A; Cannon, R O

    1995-01-01

    The bioavailability of nitric oxide (NO) in the human coronary circulation at rest and after acetylcholine (ACH)-induced vasodilation was investigated in 32 patients with angiographically normal coronary arteries. The effects of intracoronary L-NG monomethyl arginine (L-NMMA) were investigated at rest and after ACH, sodium nitroprusside, and adenosine. L-NMMA (64 mumol/min) increased resting coronary vascular resistance by 22% (P < 0.001), reduced distal epicardial coronary artery diameter by 12.6% (P < 0.001), and inhibited ACH-induced coronary epicardial and microvascular vasodilation. These effects were reversed with intracoronary L-arginine. L-NMMA did not inhibit dilation in response to sodium nitroprusside and adenosine. 23 patients were exposed to one or more coronary risk factors. The vasoconstrictor effect of L-NMMA on the epicardial and microvessels was greater in patients free of risk factors: Coronary vascular resistance was 36% higher in patients without risks, compared to 17% higher in patients with risks (P < 0.05). Both epicardial and microvascular dilator effects of ACH were greater in patients without risk factors, and the inhibition of these effects by L-NMMA was also greater in patients without risk factors. Thus: (a) NO contributes importantly to resting epicardial and coronary microvascular tone, (b) coronary vascular dilation in response to ACH is predominantly due to increased production of NO, and (c) despite the absence of angiographic evidence of atherosclerosis, exposure to coronary risk factors is associated with reduced resting and stimulated bioavailability of NO from the human coronary circulation. PMID:7706483

  1. Nitric Oxide Mediated Transcriptome Profiling Reveals Activation of Multiple Regulatory Pathways in Arabidopsis thaliana.

    PubMed

    Hussain, Adil; Mun, Bong-Gyu; Imran, Qari M; Lee, Sang-Uk; Adamu, Teferi A; Shahid, Muhammad; Kim, Kyung-Min; Yun, Byung-Wook

    2016-01-01

    Imbalance between the accumulation and removal of nitric oxide and its derivatives is a challenge faced by all plants at the cellular level, and is especially important under stress conditions. Exposure of plants to various biotic and abiotic stresses causes rapid changes in cellular redox tone potentiated by the rise in reactive nitrogen species that serve as signaling molecules in mediating defensive responses. To understand mechanisms mediated by these signaling molecules, we performed a large-scale analysis of the Arabidopsis transcriptome induced by nitrosative stress. We generated an average of 84 and 91 million reads from three replicates each of control and 1 mM S-nitrosocysteine (CysNO)-infiltrated Arabidopsis leaf samples, respectively. After alignment, more than 95% of all reads successfully mapped to the reference and 32,535 genes and 55,682 transcripts were obtained. CysNO infiltration caused differential expression of 6436 genes (3448 up-regulated and 2988 down-regulated) and 6214 transcripts (3335 up-regulated and 2879 down-regulated) 6 h post-infiltration. These differentially expressed genes were found to be involved in key physiological processes, including plant defense against various biotic and abiotic stresses, hormone signaling, and other developmental processes. After quantile normalization of the FPKM values followed by student's T-test (P < 0.05) we identified 1165 DEGs (463 up-regulated and 702 down-regulated) with at least 2-folds change in expression after CysNO treatment. Expression patterns of selected genes involved in various biological pathways were verified using quantitative real-time PCR. This study provides comprehensive information about plant responses to nitrosative stress at transcript level and would prove helpful in understanding and incorporating mechanisms associated with nitrosative stress responses in plants.

  2. Nitric Oxide Mediated Transcriptome Profiling Reveals Activation of Multiple Regulatory Pathways in Arabidopsis thaliana

    PubMed Central

    Hussain, Adil; Mun, Bong-Gyu; Imran, Qari M.; Lee, Sang-Uk; Adamu, Teferi A.; Shahid, Muhammad; Kim, Kyung-Min; Yun, Byung-Wook

    2016-01-01

    Imbalance between the accumulation and removal of nitric oxide and its derivatives is a challenge faced by all plants at the cellular level, and is especially important under stress conditions. Exposure of plants to various biotic and abiotic stresses causes rapid changes in cellular redox tone potentiated by the rise in reactive nitrogen species that serve as signaling molecules in mediating defensive responses. To understand mechanisms mediated by these signaling molecules, we performed a large-scale analysis of the Arabidopsis transcriptome induced by nitrosative stress. We generated an average of 84 and 91 million reads from three replicates each of control and 1 mM S-nitrosocysteine (CysNO)-infiltrated Arabidopsis leaf samples, respectively. After alignment, more than 95% of all reads successfully mapped to the reference and 32,535 genes and 55,682 transcripts were obtained. CysNO infiltration caused differential expression of 6436 genes (3448 up-regulated and 2988 down-regulated) and 6214 transcripts (3335 up-regulated and 2879 down-regulated) 6 h post-infiltration. These differentially expressed genes were found to be involved in key physiological processes, including plant defense against various biotic and abiotic stresses, hormone signaling, and other developmental processes. After quantile normalization of the FPKM values followed by student's T-test (P < 0.05) we identified 1165 DEGs (463 up-regulated and 702 down-regulated) with at least 2-folds change in expression after CysNO treatment. Expression patterns of selected genes involved in various biological pathways were verified using quantitative real-time PCR. This study provides comprehensive information about plant responses to nitrosative stress at transcript level and would prove helpful in understanding and incorporating mechanisms associated with nitrosative stress responses in plants. PMID:27446194

  3. Nitric Oxide Mediated Transcriptome Profiling Reveals Activation of Multiple Regulatory Pathways in Arabidopsis thaliana.

    PubMed

    Hussain, Adil; Mun, Bong-Gyu; Imran, Qari M; Lee, Sang-Uk; Adamu, Teferi A; Shahid, Muhammad; Kim, Kyung-Min; Yun, Byung-Wook

    2016-01-01

    Imbalance between the accumulation and removal of nitric oxide and its derivatives is a challenge faced by all plants at the cellular level, and is especially important under stress conditions. Exposure of plants to various biotic and abiotic stresses causes rapid changes in cellular redox tone potentiated by the rise in reactive nitrogen species that serve as signaling molecules in mediating defensive responses. To understand mechanisms mediated by these signaling molecules, we performed a large-scale analysis of the Arabidopsis transcriptome induced by nitrosative stress. We generated an average of 84 and 91 million reads from three replicates each of control and 1 mM S-nitrosocysteine (CysNO)-infiltrated Arabidopsis leaf samples, respectively. After alignment, more than 95% of all reads successfully mapped to the reference and 32,535 genes and 55,682 transcripts were obtained. CysNO infiltration caused differential expression of 6436 genes (3448 up-regulated and 2988 down-regulated) and 6214 transcripts (3335 up-regulated and 2879 down-regulated) 6 h post-infiltration. These differentially expressed genes were found to be involved in key physiological processes, including plant defense against various biotic and abiotic stresses, hormone signaling, and other developmental processes. After quantile normalization of the FPKM values followed by student's T-test (P < 0.05) we identified 1165 DEGs (463 up-regulated and 702 down-regulated) with at least 2-folds change in expression after CysNO treatment. Expression patterns of selected genes involved in various biological pathways were verified using quantitative real-time PCR. This study provides comprehensive information about plant responses to nitrosative stress at transcript level and would prove helpful in understanding and incorporating mechanisms associated with nitrosative stress responses in plants. PMID:27446194

  4. Nitric oxide fumigation for postharvest pest control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitric oxide fumigation is effective against all arthropod pests at various life stages tested. Nine insect pests at various life stages and bulb mites were subjected to nitric oxide fumigation treatments under ultralow oxygen conditions of =50 ppm O2 in 1.9L glass jars as fumigation chambers. The ...

  5. Association of renal injury with increased oxygen free radical activity and altered nitric oxide metabolism in chronic experimental hemosiderosis.

    PubMed

    Zhou, X J; Laszik, Z; Wang, X Q; Silva, F G; Vaziri, N D

    2000-12-01

    NOS expressions when compared with the control and Fe-depleted rats that showed comparable values. In conclusion, chronic iron overload resulted in iron deposition in the glomeruli and proximal tubules with various renal lesions and evidence of increased ROS activity, enhanced ROS-mediated inactivation, and sequestration of NO and compensatory up-regulation of renal eNOS and iNOS expressions. However, iron depletion was associated with reduced MDA and tissue nitrotyrosine abundance, increased urinary NOx excretion, normal nitric oxide synthase (NOS) expression, and absence of renal injury. These findings point to the possible role of ROS in chronic iron overload-induced renal injury.

  6. Ginseng, sex behavior, and nitric oxide.

    PubMed

    Murphy, Laura L; Lee, Tony Jer-Fu

    2002-05-01

    In Asia, ginseng is commonly included in herbals used for the treatment of sexual dysfunction. Recent studies in laboratory animals have shown that both Asian and American forms of ginseng enhance libido and copulatory performance. These effects of ginseng may not be due to changes in hormone secretion, but to direct effects of ginseng, or its ginsenoside components, on the central nervous system and gonadal tissues. Indeed, there is good evidence that ginsenosides can facilitate penile erection by directly inducing the vasodilatation and relaxation of penile corpus cavernosum. Moreover, the effects of ginseng on the corpus cavernosum appear to be mediated by the release and/or modification of release of nitric oxide from endothelial cells and perivascular nerves. Treatment with American ginseng also affects the central nervous system and has been shown to significantly alter the activity of hypothalamic catecholamines involved in the facilitation of copulatory behavior and hormone secretion. Recent findings that ginseng treatment decreased prolactin secretion also suggested a direct nitric oxide-mediated effect of ginseng at the level of the anterior pituitary. Thus, animal studies lend growing support for the use of ginseng in the treatment of sexual dysfunction and provide increasing evidence for a role of nitric oxide in the mechanism of ginsenoside action. PMID:12076988

  7. Diabetes-induced activation of system y+ and nitric oxide synthase in human endothelial cells: association with membrane hyperpolarization.

    PubMed Central

    Sobrevia, L; Cesare, P; Yudilevich, D L; Mann, G E

    1995-01-01

    1. The activity of the human endothelial cell L-arginine transporter (system y+) has been correlated with cGMP production (index of nitric oxide) and prostacyclin (PGI2) release in umbilical vein endothelial cells cultured from normal or gestational diabetic pregnancies. 2. In non-diabetic and diabetic cells, transport of L-arginine was Na+ and pH independent, inhibited by other cationic L-arginine analogues and unaffected by neutral amino acids. 3. Diabetes was associated with an increased Vmax for saturable L-arginine transport (4.6 +/- 0.13 vs. 9.9 +/- 0.5 pmol (microgram protein)-1 min-1, P < 0.01), but had no effect on initial rates of transport for L-serine, L-citrulline, L-leucine or 2-deoxyglucose. 4. In non-diabetic and diabetic cells, elevated K+ resulted in a concentration-dependent inhibition in the initial rates of transport for L-arginine and the membrane potential-sensitive probe tetra[3H]phenylphosphonium (TPP+). 5. When resting membrane potential was measured using the whole-cell patch voltage clamp technique, diabetic cells were hyperpolarized (-78 +/- 0.3 mV) compared with non-diabetic cells (-70 +/- 0.04 mV, P < 0.04). Accumulation of [3H]TPP+ was also increased in diabetic compared with non-diabetic cells. 6. Basal intracellular cGMP levels were elevated 2.5-fold in diabetic cells, and L-NAME (100 microM), an inhibitor of nitric oxide synthase, abolished basal cGMP accumulation in non-diabetic and diabetic cells. 7. Histamine (10 microM) had no effect on L-arginine transport but evoked significant increases in cGMP in non-diabetic and diabetic cells, which were completely inhibited by L-NAME but unaffected by superoxide dismutase. 8. Basal and histamine-stimulated PGI2 release was decreased markedly in diabetic cells. 9. Our findings demonstrate that gestational diabetes is associated with phenotypic changes in fetal endothelial cells, which result in a membrane hyperpolarization, activation of the human endothelial cell L-arginine transporter

  8. Two Dimensional Polymer That Generates Nitric Oxide.

    DOEpatents

    McDonald, William F.; Koren, Amy B.

    2005-10-04

    A polymeric composition that generates nitric oxide and a process for rendering the surface of a substrate nonthrombogenic by applying a coating of the polymeric composition to the substrate are disclosed. The composition comprises: (1) a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, and (ii) a crosslinking agent containing functional groups capable of reacting with the amino groups; and (2) a plurality of nitric oxide generating functional groups associated with the crosslinked chemical combination. Once exposed to a physiological environment, the coating generates nitric oxide thereby inhibiting platelet aggregation. In one embodiment, the nitric oxide generating functional groups are provided by a nitrated compound (e.g., nitrocellulose) imbedded in the polymeric composition. In another embodiment, the nitric oxide generating functional groups comprise N2O2- groups covalently bonded to amino groups on the polymer.

  9. New ambuic acid derivatives from the solid culture of Pestalotiopsis neglecta and their nitric oxide inhibitory activity

    PubMed Central

    Qi, Qiu-Yue; Li, Er-Wei; Han, Jun-Jie; Pei, Yun-Fei; Ma, Ke; Bao, Li; Huang, Ying; Zhao, Feng; Liu, Hong-Wei

    2015-01-01

    Four new ambuic acid derivatives (1–4), and four known derivatives (5–8), were isolated from the solid culture of a plant pathogenic fungus Pestalotiopsis neglecta. Their structures were elucidated by extensive NMR experiments. The absolute configuration of the C-16 secondary alcohol in 1 was deduced via the CD data of the in situ formed [Rh2(OCOCF3)4] complex with the acetonide derivative of 1. The absolute configuration in 3 was assigned by comparison of the experimental and simulated electronic circular dichroism (ECD) spectrum. The NMR data of compound 5 was reported for the first time. In the nitric oxide (NO) inhibition assay, compounds 4, 6 and 7 showed inhibitory activity against the NO production in the lipopolysaccharide (LPS)-induced macrophage with IC50 values of 88.66, 11.20, and 20.80 µM, respectively. PMID:25989228

  10. Water-soluble two-photon absorbing nitrosyl complex for light-activated therapy through nitric oxide release.

    PubMed

    Zheng, Qingdong; Bonoiu, Adela; Ohulchanskyy, Tymish Y; He, Guang S; Prasad, Paras N

    2008-01-01

    A water-soluble nitrosyl complex with large two-photon absorption was synthesized by incorporating a two-photon absorbing chromophore with tetra(ethylene glycol) units, into the Roussin's red salt. The nitrosyl complex exhibits quenched emission due to energy transfer from the two-photon chromophore to the Roussin's red salt. The nitric oxide (NO) release induced by one- or two-photon irradiation was detected by EPR spectroscopy with a chemical probe, the Fe(II)- N-(dithiocarbamoyl)- N-methyl- d-glucamine (Fe-MGD) complex. Increased one- or two-photon excited fluorescence, with a concomitant photochemical release of NO, was observed upon one- or two-photon light irradiation. With the observed light-dependent cytotoxicity against cancer cells of the water-soluble nitrosyl complex, it was demonstrated that two-photon-functionalized nitrosyl complexes can be effective NO donors for light-activated treatment.

  11. Stereospecific inhibition of nitric oxide production in macrophage cells by flavanonols: Synthesis and the structure-activity relationship.

    PubMed

    Jiang, Wen-Jun; Ishiuchi, Kan'ichiro; Furukawa, Megumi; Takamiya, Tomoko; Kitanaka, Susumu; Iijima, Hiroshi

    2015-11-01

    To explore the structure-activity relationships on the inhibitory activity of flavanonols against nitric oxide (NO) production in inflammatory cells, we synthesized 19 flavanonols which shared a common 3,5,7-trihydroxychroman scaffold. A range of substitutions was included in the B ring in order to investigate the structure-activity relationship. We also succeeded in isolating stereoisomers from 16 of the flavanonols using chiral column chromatography. The inhibitory effects of these compounds on NO production were examined in RAW 264.7 cells (a murine macrophage-like cell line), which were activated by lipopolysaccharide (LPS). We only observed inhibitory activity against NO production in (2R,3R) stereoisomers, while the inhibitory activities of (2S,3S) stereoisomers were significantly weaker. We also evaluated the free radical scavenging potential of the flavanonols using 1,1-diphenyl-2-picrylhydrazyl (DPPH). Each stereoisomer indicated the equivalent DPPH scavenging potential as expected. The radical scavenging activity was not correlated with the inhibitory activity against NO. The inhibition of NO production by flavanonols is stereospecific and cannot simply be explained by their radical scavenging activity. We propose the possible existence of a 'target' molecule for flavanonols which is involved in the production and/or regulation of NO in RAW 264.7 cells.

  12. Endothelial and Neuronal Nitric Oxide Activate Distinct Pathways on Sympathetic Neurotransmission in Rat Tail and Mesenteric Arteries.

    PubMed

    Sousa, Joana Beatriz; Vieira-Rocha, Maria Sofia; Arribas, Silvia M; González, Maria Carmen; Fresco, Paula; Diniz, Carmen

    2015-01-01

    Nitric oxide (NO) seems to contribute to vascular homeostasis regulating neurotransmission. This work aimed at assessing the influence of NO from different sources and respective intracellular pathways on sympathetic neurotransmission, in two vascular beds. Electrically-evoked [3H]-noradrenaline release was assessed in rat mesenteric and tail arteries in the presence of NO donors or endothelial/neuronal nitric oxide synthase (NOS) inhibitors. The influence of NO on adenosine-mediated effects was also studied using selective antagonists for adenosine receptors subtypes. Location of neuronal NOS (nNOS) was investigated by immunohistochemistry (with specific antibodies for nNOS and for Schwann cells) and Confocal Microscopy. Results indicated that: 1) in mesenteric arteries, noradrenaline release was reduced by NO donors and it was increased by nNOS inhibitors; the effect of NO donors was only abolished by the adenosine A1 receptors antagonist; 2) in tail arteries, noradrenaline release was increased by NO donors and it was reduced by eNOS inhibitors; adenosine receptors antagonists were devoid of effect; 3) confocal microscopy showed nNOS staining in adventitial cells, some co-localized with Schwann cells. nNOS staining and its co-localization with Schwann cells were significantly lower in tail compared to mesenteric arteries. In conclusion, in mesenteric arteries, nNOS, mainly located in Schwann cells, seems to be the main source of NO influencing perivascular sympathetic neurotransmission with an inhibitory effect, mediated by adenosine A1 receptors activation. Instead, in tail arteries endothelial NO seems to play a more relevant role and has a facilitatory effect, independent of adenosine receptors activation.

  13. Endothelial and Neuronal Nitric Oxide Activate Distinct Pathways on Sympathetic Neurotransmission in Rat Tail and Mesenteric Arteries

    PubMed Central

    Sousa, Joana Beatriz; Vieira-Rocha, Maria Sofia; Arribas, Silvia M.; González, Maria Carmen; Fresco, Paula; Diniz, Carmen

    2015-01-01

    Nitric oxide (NO) seems to contribute to vascular homeostasis regulating neurotransmission. This work aimed at assessing the influence of NO from different sources and respective intracellular pathways on sympathetic neurotransmission, in two vascular beds. Electrically-evoked [3H]-noradrenaline release was assessed in rat mesenteric and tail arteries in the presence of NO donors or endothelial/neuronal nitric oxide synthase (NOS) inhibitors. The influence of NO on adenosine-mediated effects was also studied using selective antagonists for adenosine receptors subtypes. Location of neuronal NOS (nNOS) was investigated by immunohistochemistry (with specific antibodies for nNOS and for Schwann cells) and Confocal Microscopy. Results indicated that: 1) in mesenteric arteries, noradrenaline release was reduced by NO donors and it was increased by nNOS inhibitors; the effect of NO donors was only abolished by the adenosine A1 receptors antagonist; 2) in tail arteries, noradrenaline release was increased by NO donors and it was reduced by eNOS inhibitors; adenosine receptors antagonists were devoid of effect; 3) confocal microscopy showed nNOS staining in adventitial cells, some co-localized with Schwann cells. nNOS staining and its co-localization with Schwann cells were significantly lower in tail compared to mesenteric arteries. In conclusion, in mesenteric arteries, nNOS, mainly located in Schwann cells, seems to be the main source of NO influencing perivascular sympathetic neurotransmission with an inhibitory effect, mediated by adenosine A1 receptors activation. Instead, in tail arteries endothelial NO seems to play a more relevant role and has a facilitatory effect, independent of adenosine receptors activation. PMID:26075386

  14. Endothelial and Neuronal Nitric Oxide Activate Distinct Pathways on Sympathetic Neurotransmission in Rat Tail and Mesenteric Arteries.

    PubMed

    Sousa, Joana Beatriz; Vieira-Rocha, Maria Sofia; Arribas, Silvia M; González, Maria Carmen; Fresco, Paula; Diniz, Carmen

    2015-01-01

    Nitric oxide (NO) seems to contribute to vascular homeostasis regulating neurotransmission. This work aimed at assessing the influence of NO from different sources and respective intracellular pathways on sympathetic neurotransmission, in two vascular beds. Electrically-evoked [3H]-noradrenaline release was assessed in rat mesenteric and tail arteries in the presence of NO donors or endothelial/neuronal nitric oxide synthase (NOS) inhibitors. The influence of NO on adenosine-mediated effects was also studied using selective antagonists for adenosine receptors subtypes. Location of neuronal NOS (nNOS) was investigated by immunohistochemistry (with specific antibodies for nNOS and for Schwann cells) and Confocal Microscopy. Results indicated that: 1) in mesenteric arteries, noradrenaline release was reduced by NO donors and it was increased by nNOS inhibitors; the effect of NO donors was only abolished by the adenosine A1 receptors antagonist; 2) in tail arteries, noradrenaline release was increased by NO donors and it was reduced by eNOS inhibitors; adenosine receptors antagonists were devoid of effect; 3) confocal microscopy showed nNOS staining in adventitial cells, some co-localized with Schwann cells. nNOS staining and its co-localization with Schwann cells were significantly lower in tail compared to mesenteric arteries. In conclusion, in mesenteric arteries, nNOS, mainly located in Schwann cells, seems to be the main source of NO influencing perivascular sympathetic neurotransmission with an inhibitory effect, mediated by adenosine A1 receptors activation. Instead, in tail arteries endothelial NO seems to play a more relevant role and has a facilitatory effect, independent of adenosine receptors activation. PMID:26075386

  15. Cerivastatin activates endothelial calcium-activated potassium channels and thereby modulates endothelial nitric oxide production and cell proliferation.

    PubMed

    Kuhlmann, Christoph Rüdiger Wolfram; Gast, Christine; Li, Fang; Schäfer, Matthias; Tillmanns, Harald; Waldecker, Bernd; Wiecha, Johannes

    2004-04-01

    Statins are known to counteract the process of arteriosclerosis by exerting direct pleiotropic effects on vascular endothelium. The aim of this study was to investigate a possible effect of cerivastatin on endothelial Ca(2+)-activated K+ channels (BK(Ca)) and to assess their contribution to cerivastatin-mediated changes of endothelial nitric oxide (NO) production and proliferation. Membrane potential was measured using bis-1,3-dibutylbarbituric acid-trimethine oxonol-fluorescence imaging. Patch-clamp recordings of BK(Ca) were performed on cultured human umbilical vein endothelial cells. NO production was measured using 4,5-diaminofluorescein-fluorescence imaging and a [(3)H]cGMP RIA. Proliferation was analyzed by means of cell counts and [(3)H]thymidine incorporation (TI). Cerivastatin (0.001 to 0.05 micromol/L) caused a significant membrane hyperpolarization (n = 30; P < 0.05). This effect was abolished using the BK(Ca) inhibitor iberiotoxin (IBX; 100 nmol/L). The addition of mevalonate (500 micromol/L) blocked the BK(Ca) activation induced by cerivastatin (n = 19; P < 0.05). Endothelial cGMP level was increased by acetylcholine (ACh; 1 micromol/L). The combination of ACh and cerivastatin additionally increased cGMP levels, with a maximum at 0.03 micromol/L cerivastatin (84%; n = 10, P < 0.01). ACh-induced increase of cGMP-level was significantly reduced by IBX (n = 10, P < 0.01) as it was with all combined administrations of ACh and cerivastatin. 4,5-Diaminofluorescein-fluorescence measurements revealed a significant increase of NO levels by cerivastatin, which was abolished by IBX (n = 30; P < 0.05). Cell counts and TI demonstrated significant inhibition of human umbilical vein endothelial cell proliferation with a maximum at 0.03 micro mol/L (cell count, -32.2%; TI, -70%; n = 12; P < 0.01). These data show that cerivastatin activates endothelial BK(Ca), which plays an important role in the signaling of cerivastatin-mediated endothelial NO production and

  16. Nitric oxide in liver diseases.

    PubMed

    Iwakiri, Yasuko; Kim, Moon Young

    2015-08-01

    Nitric oxide (NO) and its derivatives play important roles in the physiology and pathophysiology of the liver. Despite its diverse and complicated roles, certain patterns of the effect of NO on the pathogenesis and progression of liver diseases are observed. In general, NO derived from endothelial NO synthase (eNOS) in liver sinusoidal endothelial cells (LSECs) is protective against disease development, while inducible NOS (iNOS)-derived NO contributes to pathological processes. This review addresses the roles of NO in the development of various liver diseases with a focus on recently published articles. We present here two recent advances in understanding NO-mediated signaling - nitrated fatty acids (NO2-FAs) and S-guanylation - and conclude with suggestions for future directions in NO-related studies on the liver. PMID:26027855

  17. NITRIC OXIDE IN LIVER DISEASES

    PubMed Central

    Iwakiri, Yasuko; Kim, Moon Young

    2015-01-01

    Nitric oxide (NO) and its derivatives play important roles in the physiology and pathophysiology of the liver. Despite its diverse and complicated roles, certain patterns of the effect of NO on the pathogenesis and progression of liver diseases are observed. In general, NO derived from endothelial NO synthase (eNOS) in liver sinusoidal endothelial cells (LSECs) is protective against disease development, while inducible NOS (iNOS)-derived NO contributes to pathological processes. This review addresses the roles of NO in the development of various liver diseases with a focus on recently published articles. We present here two recent advances in understanding NO-mediated signaling, nitrated fatty acids and S-guanylation, and conclude with suggestions on future directions of NO-related studies on the liver. PMID:26027855

  18. Exhaled nitric oxide in sarcoidosis

    PubMed Central

    Wilsher, M; Fergusson, W; Milne, D; Wells, A

    2005-01-01

    Background: Increased production of nitric oxide (NO) by the lower respiratory tract is viewed as a marker of airway inflammation in asthma and bronchiectasis. NO is a potentially important immune modulator, inhibiting the release of several key pro-inflammatory cytokines. As sarcoidosis is characterised by granulomatous airway inflammation, we hypothesised that exhaled NO levels might be raised in sarcoidosis and correlate with the morphological extent and functional severity of disease. Methods: Fifty two patients with sarcoidosis (29 men) of mean age 42 years underwent thin section computed tomography (CT), pulmonary function tests, and measurement of exhaled NO. Results: Exhaled NO levels (median 6.8 ppb, range 2.4–21.8) did not differ significantly from values in 44 control subjects, and were not related to the extent of individual CT abnormalities or the level of pulmonary function impairment. Conclusion: Exhaled NO levels are not increased in pulmonary sarcoidosis. PMID:16244094

  19. Nanocarriers for Nitric Oxide Delivery

    PubMed Central

    Saraiva, Juliana; Marotta-Oliveira, Samantha S.; Cicillini, Simone Aparecida; Eloy, Josimar de Oliveira; Marchetti, Juliana Maldonado

    2011-01-01

    Nitric oxide (NO) is a promising pharmaceutical agent that has vasodilative, antibacterial, and tumoricidal effects. To study the complex and wide-ranging roles of NO and to facilitate its therapeutic use, a great number of synthetic compounds (e.g., nitrosothiols, nitrosohydroxyamines, N-diazeniumdiolates, and nitrosyl metal complexes) have been developed to chemically stabilize and release NO in a controlled manner. Although NO is currently being exploited in many biomedical applications, its use is limited by several factors, including a short half-life, instability during storage, and potential toxicity. Additionally, efficient methods of both localized and systemic in vivo delivery and dose control are needed. One strategy for addressing these limitations and thus increasing the utility of NO donors is based on nanotechnology. PMID:21869934

  20. Neutralizing a Surface Charge on the FMN Subdomain Increases the Activity of Neuronal Nitric-oxide Synthase by Enhancing the Oxygen Reactivity of the Enzyme Heme-Nitric Oxide Complex*

    PubMed Central

    Haque, Mohammad Mahfuzul; Fadlalla, Mohammed; Wang, Zhi-Qiang; Ray, Sougata Sinha; Panda, Koustubh; Stuehr, Dennis J.

    2009-01-01

    Nitric-oxide synthases (NOSs) are calmodulin-dependent flavoheme enzymes that oxidize l-Arg to nitric oxide (NO) and l-citrulline. Their catalytic behaviors are complex and are determined by their rates of heme reduction (kr), ferric heme-NO dissociation (kd), and ferrous heme-NO oxidation (kox). We found that point mutation (E762N) of a conserved residue on the enzyme's FMN subdomain caused the NO synthesis activity to double compared with wild type nNOS. However, in the absence of l-Arg, NADPH oxidation rates suggested that electron flux through the heme was slower in E762N nNOS, and this correlated with the mutant having a 60% slower kr. During NO synthesis, little heme-NO complex accumulated in the mutant, compared with ∼50–70% of the wild-type nNOS accumulating as this complex. This suggested that the E762N nNOS is hyperactive because it minimizes buildup of an inactive ferrous heme-NO complex during NO synthesis. Indeed, we found that kox was 2 times faster in the E762N mutant than in wild-type nNOS. The mutational effect on kox was independent of calmodulin. Computer simulation and experimental measures both indicated that the slower kr and faster kox of E762N nNOS combine to lower its apparent Km,O2 for NO synthesis by at least 5-fold, which in turn increases its V/Km value and enables it to be hyperactive in steady-state NO synthesis. Our work underscores how sensitive nNOS activity is to changes in the kox and reveals a novel means for the FMN module or protein-protein interactions to alter nNOS activity. PMID:19473991

  1. Inorganic nitrite attenuates NADPH oxidase-derived superoxide generation in activated macrophages via a nitric oxide-dependent mechanism.

    PubMed

    Yang, Ting; Peleli, Maria; Zollbrecht, Christa; Giulietti, Alessia; Terrando, Niccolo; Lundberg, Jon O; Weitzberg, Eddie; Carlström, Mattias

    2015-06-01

    Oxidative stress contributes to the pathogenesis of many disorders, including diabetes and cardiovascular disease. Immune cells are major sources of superoxide (O2(∙-)) as part of the innate host defense system, but exaggerated and sustained O2(∙-) generation may lead to progressive inflammation and organ injuries. Previous studies have proven organ-protective effects of inorganic nitrite, a precursor of nitric oxide (NO), in conditions manifested by oxidative stress and inflammation. However, the mechanisms are still not clear. This study aimed at investigating the potential role of nitrite in modulating NADPH oxidase (NOX) activity in immune cells. Mice peritoneal macrophages or human monocytes were activated by lipopolysaccharide (LPS), with or without coincubation with nitrite. O2(∙-) and peroxynitrite (ONOO(-)) formation were detected by lucigenin-based chemiluminescence and fluorescence techniques, respectively. The intracellular NO production was measured by DAF-FM DA fluorescence. NOX isoforms and inducible NO synthase (iNOS) expression were detected by qPCR. LPS increased both O2(∙-) and ONOO(-) production in macrophages, which was significantly reduced by nitrite (10µmol/L). Mechanistically, the effects of nitrite are (1) linked to increased NO generation, (2) similar to that observed with the NO donor DETA-NONOate, and (3) can be abolished by the NO scavenger carboxy-PTIO or by the xanthine oxidase (XO) inhibitor febuxostat. Nox2 expression was increased in activated macrophages, but was not influenced by nitrite. However, nitrite attenuated LPS-induced upregulation of iNOS expression. Similar to that observed in mice macrophages, nitrite also reduced O2(∙-) generation in LPS-activated human monocytes. In conclusion, XO-mediated reduction of nitrite attenuates NOX activity in activated macrophages, which may modulate the inflammatory response. PMID:25724690

  2. Neuroprotective effect of allicin against traumatic brain injury via Akt/endothelial nitric oxide synthase pathway-mediated anti-inflammatory and anti-oxidative activities.

    PubMed

    Chen, Wei; Qi, Jun; Feng, Feng; Wang, Mao-de; Bao, Gang; Wang, Tuo; Xiang, Mu; Xie, Wan-Fu

    2014-03-01

    Allicin, one of the main biologically active compounds derived from garlic, has been shown to exert various anti-oxidative and anti-inflammatory activities in in vitro and in vivo studies. Here, we sought to investigate the potential neuroprotective effects of allicin against traumatic brain injury (TBI) in rats. We found that allicin treatment (10 and 50mg/kg, not 1mg/kg) significantly reduced brain edema and motor functional deficits, as well as apoptotic neuronal cell death in injured cortex. These protective effects could be observed even if the administration was delayed to 4h after injury. Moreover, allicin treatment decreased the expression levels of MDA and protein carbonyl, preserved the endogenous antioxidant enzyme activities, and suppressed the expression of inflammatory cytokines. The results of Western blot analysis showed that allicin increased the phosphorylation of Akt and endothelial nitric oxide synthase (eNOS). Blocking Akt/eNOS pathway activation by specific inhibitor LY294002 (10μL, 10mmol/L) or L-NIO (0.5mg/kg) partly reversed the protective effects of allicin and its anti-inflammatory activities. The allicin induced anti-oxidative activity was partly prevented by LY294002, but not L-NIO. In summary, our data strongly suggested that allicin treatment at an appropriate dose can exert protective effect against TBI through Akt/eNOS pathway-mediated anti-inflammatory and anti-oxidative activities.

  3. Expression of natriuretic peptides, nitric oxide synthase, and guanylate cyclase activity in frog mesonephros during the annual cycle.

    PubMed

    Fenoglio, Carla; Visai, Livia; Addario, Concetta; Gerzeli, Giuseppe; Milanesi, Gloria; Vaccarone, Rita; Barni, Sergio

    2004-06-01

    Natriuretic peptides (NPs), a family of structurally related hormones and nitric oxide (NO), generated by nitric oxide synthase (NOS), are believed to be involved in the regulation of fluid balance and sodium homeostasis. Differential expression and regulation of these factors depend on both physiological and pathological conditions. Both NPs and NO act in target organs through the activation of guanylate cyclase (GC) and the generation of guanosine 3',5'-cyclic monophosphate (cGMP), which is considered a common messenger for the action of these factors. The present study was designed to investigate--by histochemical methods--the expression of some NPs (proANP and ANP) and isoforms of NOS (neuronal NOS, nNOS, and inducible NOS, iNOS) in the mesonephros of Rana esculenta in different periods of the year including hibernation, to evaluate possible seasonal changes in their expression. We also studied the enzyme activity of NOS-related nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) and of GC. The experiments were performed on pieces of kidney of R. esculenta collected in their natural environment during active and hibernating life. The study was carried out using immunohistochemical techniques to demonstrate proANP, ANP, and some NOS isoforms. Antigen capture by enzyme linked immunosorbent assay (ELISA) was also performed to determine the presence of NPs in the frog kidney extract. Enzyme histochemistry was used to demonstrate the NOS-related NADPHd activity at light microscopy; GC activity was visualized at the electron microscope, using cerium as capture agent. The application of the immunohistochemical techniques demonstrated that frog mesonephros tubules express different patterns of distribution and/or expression of ANP and NOS during the annual cycle. Comparing the results obtained on active and hibernating frogs has provided interesting data; the NOS/NADPHd and GC activities showed some variations as well. Furthermore, the presence of NPs in

  4. Antioxidant activity, inhibition of nitric oxide overproduction, and in vitro antiproliferative effect of maple sap and syrup from Acer saccharum.

    PubMed

    Legault, Jean; Girard-Lalancette, Karl; Grenon, Carole; Dussault, Catherine; Pichette, André

    2010-04-01

    Antioxidant activity, inhibition of nitric oxide (NO) overproduction, and antiproliferative effect of ethyl acetate extracts of maple sap and syrup from 30 producers were evaluated in regard to the period of harvest in three different regions of Québec, Canada. Oxygen radical absorbance capacity (ORAC) values of maple sap and syrup extracts are, respectively, 12 +/- 6 and 15 +/- 5 micromol of Trolox equivalents (TE)/mg. The antioxidant activity was also confirmed by a cell-based assay. The period of harvest has no statistically significant incidence on the antioxidant activity of both extracts. The antioxidant activity of pure maple syrup was also determined using the ORAC assay. Results indicate that the ORAC value of pure maple syrup (8 +/- 2 micromol of TE/mL) is lower than the ORAC value of blueberry juice (24 +/- 1 micromol of TE/mL) but comparable to the ORAC values of strawberry (10.7 +/- 0.4 micromol of TE/mL) and orange (10.8 +/- 0.5 micromol of TE/mL) juices. Maple sap and syrup extracts showed to significantly inhibit lipopolysaccharide-induced NO overproduction in RAW264.7 murine macrophages. Maple syrup extract was significantly more active than maple sap extract, suggesting that the transformation of maple sap into syrup increases NO inhibition activity. The highest NO inhibition induced by the maple syrup extracts was observed at the end of the season. Moreover, darker maple syrup was found to be more active than clear maple syrup, suggesting that some colored oxidized compounds could be responsible in part for the activity. Finally, maple syrup extracts (50% inhibitory concentration = 42 +/- 6 microg/mL) and pure maple syrup possess a selective in vitro antiproliferative activity against cancer cells.

  5. Glycoconjugates isolated from Trypanosoma cruzi but not from Leishmania species membranes trigger nitric oxide synthesis as well as microbicidal activity in IFN-gamma-primed macrophages.

    PubMed

    Camargo, M M; Andrade, A C; Almeida, I C; Travassos, L R; Gazzinelli, R T

    1997-12-15

    In the present study, we investigated the role of glycosylphosphatidylinositol-anchored mucin-like glycoproteins (GPI-mucins) from Trypanosoma cruzi trypomastigotes in triggering the synthesis of nitric oxide as well as the microbicidal activity in murine macrophages. Our results show that GPI-mucins isolated from trypomastigote membranes are potent inducers of nitric oxide synthesis by IFN-gamma-primed macrophages, even at concentrations as low as 10 ng/ml. Our data also indicate the important role of glycosylphosphatidylinositol anchors from GPI-mucins as the second signal responsible for induction of nitric oxide synthesis by macrophages. To further investigate the role of these parasite molecules in inducing parasiticidal function, we cultured macrophages in the presence or absence of trypomastigote GPI-mucins and/or IFN-gamma and then infected these cells with either Leishmania spp. or T. cruzi. IFN-gamma was sufficient to induce microbial activity in macrophages infected with T. cruzi trypomastigotes. In contrast, killing of different species of Leishmania was further enhanced when macrophages exposed to IFN-gamma were also costimulated with trypomastigote-derived GPI-mucins. Our results also indicate that different glycolipids obtained from Leishmania major or Leishmania donovani (i.e., lipophosphoglycans or glycoinositolphospholipids) were unable to potentiate nitric oxide synthesis and/or microbicidal activity displayed by IFN-gamma-primed macrophages.

  6. Aldosterone increases kidney tubule cell oxidants through calcium-mediated activation of NADPH oxidase and nitric oxide synthase.

    PubMed

    Queisser, Nina; Schupp, Nicole; Stopper, Helga; Schinzel, Reinhard; Oteiza, Patricia I

    2011-12-01

    Chronic hyperaldosteronism has been associated with an increased cancer risk. We recently showed that aldosterone causes an increase in cell oxidants, DNA damage, and NF-κB activation. This study investigated the mechanisms underlying aldosterone-induced increase in cell oxidants in kidney tubule cells. Aldosterone caused an increase in both reactive oxygen and reactive nitrogen (RNS) species. The involvement of the activation of NADPH oxidase in the increase in cellular oxidants was demonstrated by the inhibitory action of the NADPH oxidase inhibitors DPI, apocynin, and VAS2870 and by the migration of the p47 subunit to the membrane. NADPH oxidase activation occurred as a consequence of an increase in cellular calcium levels and was mediated by protein kinase C. The prevention of RNS increase by BAPTA-AM, W-7, and L-NAME indicates a calcium-calmodulin activation of NOS. A similar pattern of effects of the NADPH oxidase and NOS inhibitors was observed for aldosterone-induced DNA damage and NF-κB activation, both central to the pathogenesis of chronic aldosteronism. In summary, this paper demonstrates that aldosterone, via the mineralocorticoid receptor, causes an increase in kidney cell oxidants, DNA damage, and NF-κB activation through a calcium-mediated activation of NADPH oxidase and NOS. Therapies targeting calcium, NOS, and NADPH oxidase could prevent the adverse effects of hyperaldosteronism on kidney function as well as its potential oncogenic action.

  7. Melatonin and its precursors scavenge nitric oxide

    SciTech Connect

    Noda, Y.; Mori, A.; Liburdy, R.; Packer, L.

    1998-12-01

    Nitric oxide (NO) scavenging activity of melatonin, N-acetyl-5-hydroxytryptamine, serotonin, 5-hydroxytryptophan and L-tryptophan was examined by the Griess reaction using flow injection analysis. 1-Hydroxy-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl-1-triazene(NOC-7) was used as NO generator. The Griess reagent stoichiometrically reacts with NO2-, which was converted by a cadmium-copper reduction column from the stable end products of NO oxidation. Except for tryptophan, all the compounds examined scavenged NO in a dose-dependent manner. Melatonin, which has a methoxy group in the 5-position and an acetyl side chain, exhibited the most potent scavenging activity among the compounds tested. Serotonin, N-acetyl-5-hydroxytryptamine, and 5-hydroxytryptophan, respectively, showed moderate scavenging activity compared to melatonin. Tryptophan, which has neither a methoxy nor a hydroxyl group in the 5-position, exhibited the least NO scavenging activity.

  8. Production of nitric oxide using a microwave plasma torch and its application to fungal cell differentiation

    NASA Astrophysics Data System (ADS)

    Na, Young Ho; Kumar, Naresh; Kang, Min-Ho; Cho, Guang Sup; Choi, Eun Ha; Park, Gyungsoon; Uhm, Han Sup

    2015-03-01

    The generation of nitric oxide by a microwave plasma torch is proposed for its application to cell differentiation. A microwave plasma torch was developed based on basic kinetic theory. The analytical theory indicates that nitric oxide density is nearly proportional to oxygen molecular density and that the high-temperature flame is an effective means of generating nitric oxide. Experimental data pertaining to nitric oxide production are presented in terms of the oxygen input in units of cubic centimeters per minute. The apparent length of the torch flame increases as the oxygen input increases. The various levels of nitric oxide are observed depending on the flow rate of nitrogen gas, the mole fraction of oxygen gas, and the microwave power. In order to evaluate the potential of nitric oxide as an activator of cell differentiation, we applied nitric oxide generated from the microwave plasma torch to a model microbial cell (Neurospora crassa: non-pathogenic fungus). Germination and hyphal differentiation of fungal cells were not dramatically changed but there was a significant increase in spore formation after treatment with nitric oxide. In addition, the expression level of a sporulation related gene acon-3 was significantly elevated after 24 h upon nitric oxide treatment. Increase in the level of nitric oxide, nitrite and nitrate in water after nitric oxide treatment seems to be responsible for activation of fungal sporulation. Our results suggest that nitric oxide generated by plasma can be used as a possible activator of cell differentiation and development.

  9. Melatonin and nitric oxide modulate glutathione content and glutathione reductase activity in sunflower seedling cotyledons accompanying salt stress.

    PubMed

    Kaur, Harmeet; Bhatla, Satish C

    2016-09-30

    The present findings demonstrate significant modulation of total glutathione content, reduced glutathione (GSH) content, oxidized glutathione (GSSG) content, GSH/GSSG ratio and glutathione reductase (GR; EC 1.6.4.2) activity in dark-grown seedling cotyledons in response to salt-stress (120 mM NaCl) in sunflower (Helianthus annuus L.) seedlings. A differential spatial distribution of GR activity (monitored by confocal laser scanning microscopic (CLSM) imaging) is also evident. Melatonin and nitric oxide (NO) differentially ameliorate salt stress effect by modulating GR activity and GSH content in seedling cotyledons. Total glutathione content (GSH + GSSG) exhibit a seedling age-dependent increase in the cotyledons, more so in salt-stressed conditions and when subjected to melatonin treatment. Seedlings raised in presence of 15 μM of melatonin exhibit significant increase in GR activity in cotyledon homogenates (10,000 g supernatant) coinciding with significant increase in GSH content. GSSG content and GSH/GSSG ratio also increased due to melatonin treatment. A correlation is thus evident in NaCl-sensitized modulation of GSH content and GR activity by melatonin. GSH content is down regulated by NO provided as 250 μM of sodium nitroprusside (SNP) although total glutathione content remained in similar range. A reversal of response (enhanced total glutathione accumulation) by NO scavenger (cPTIO) highlights the critical role of NO in modulating glutathione homeostasis. SNP lowers the activity of hydroxyindole-O-methyltransferase (HIOMT) - a regulatory enzyme in melatonin biosynthesis in control seedlings whereas its activity is upregulated in salt-stressed seedling cotyledons. Melatonin content of seedling cotyledons is also modulated by NO. NO and melatonin thus seem to modulate GR activity and GSH content during seedling growth under salt stress. PMID:27432590

  10. Nitric oxide changes its role as a modulator of respiratory motor activity during development in the bullfrog (Rana catesbeiana).

    PubMed

    Hedrick, Michael S; Chen, Anna K; Jessop, Kristy L

    2005-10-01

    Nitric oxide (NO) is a unique chemical messenger that has been shown to play a role in the modulation of breathing in amphibians and other vertebrates. In the post-metamorphic tadpole and adult amphibian brainstem, NO, acting via the neuronal isoform of nitric oxide synthase (nNOS), is excitatory to the generation of lung burst activity. In this study, we examine the modulation of breathing by NO during development of the amphibian brainstem. Isolated brainstem preparations from pre-metamorphic and late-stage post-metamorphic tadpoles (Rana catesbeiana) were used to determine the role of NO in modulating central respiratory neural activity. Respiratory neural activity was monitored with suction electrodes recording extracellular activity of cranial nerve rootlets that innervate respiratory musculature. Brainstems were superfused with an artificial cerebrospinal fluid (aCSF) at 20-22 degrees C containing l-nitroarginine (l-NA; 1-10 mM), a non-selective NOS inhibitor. In pre-metamorphic tadpoles, l-NA increased fictive gill ventilation frequency and amplitude, and increased lung burst frequency. By contrast, l-NA applied to the post-metamorphic tadpole brainstem had little effect on fictive buccal activity, but significantly decreased lung burst frequency and the frequency of lung burst episodes. These data indicate that early in development, NO provides a tonic inhibitory input to gill and lung burst activity, but as development progresses, NO provides an excitatory input to lung ventilation. This changing role for NO coincides with the shift in importance in the different respiratory modes during development in amphibians; that is, pre-metamorphic tadpoles rely predominantly on gill ventilation whereas post-metamorphic tadpoles have lost the gills and are obligate air-breathers primarily using lungs for gas exchange. We hypothesize that NO provides a tonic input to the respiratory CPG during development and this changing role reflects the modulatory influence of NO

  11. Rapid nontranscriptional activation of endothelial nitric oxide synthase mediates increased cerebral blood flow and stroke protection by corticosteroids

    PubMed Central

    Limbourg, Florian P.; Huang, Zhihong; Plumier, Jean-Christophe; Simoncini, Tommaso; Fujioka, Masayuki; Tuckermann, Jan; Schütz, Günther; Moskowitz, Michael A.; Liao, James K.

    2002-01-01

    Many cellular responses to corticosteroids involve the transcriptional modulation of target genes by the glucocorticoid receptor (GR). A rapid, non-nuclear effect of GR was found to mediate neuroprotection. High-dose corticosteroids (20 mg/kg intraperitoneally), given within 2 hours of transient cerebral ischemia, acutely increased endothelial nitric oxide synthase (eNOS) activity, augmented regional cerebral blood flow (CBF) by 40% to 50%, and reduced cerebral infarct size by 32%. These neuroprotective effects of corticosteroids were abolished by the GR antagonist RU486 and by inhibition of phosphatidylinositol 3-kinase (PI3K), and were absent in eNOS–/– mice. To determine the mechanism by which GR activated eNOS, we measured the effect of corticosteroids on PI3K and the protein kinase Akt. In a ligand-dependent manner, GR activated PI3K and Akt in vitro and in vivo caused NO-dependent vasodilation, which was blocked by cotreatment with RU486 or the PI3K inhibitor LY294002 but not by transcriptional inhibitors. Indeed, a mutant GR, which cannot dimerize and bind to DNA, still activated PI3K and Akt in response to corticosteroids. These findings indicate that non-nuclear GR rapidly activates eNOS through the PI3K/Akt pathway and suggest that this mechanism mediates the acute neuroprotective effects of corticosteroids through augmentation of CBF. PMID:12464678

  12. S-2-amino-5-(2-nitroimidazol-1-yl)pentanoic acid: a model for potential bioreductively activated prodrugs for inhibitors of nitric oxide synthase (NOS) activity.

    PubMed

    Ulhaq, S; Naylor, M A; Chinje, E C; Threadgill, M D; Stratford, I J

    1997-01-01

    Treatment of 1,1-dimethylethyl S-(2-1,1-dimethylethoxycarbonylamino)-5-bromopentanoate with 1-potassio-2-nitroimidazole, followed by deprotection, afforded S-2-amino-5-(2-nitroimidazol-1-yl)pentanoic acid, which was reduced to S-2-amino-5-(2-aminoimidazol-1-yl)pentanoic acid. This aminoimadazole inhibited rat brain nitric oxide synthase (NOS) activity 3.2 times more potently than did the nitro analogue. Thus S-2-amino-5-(2-nitroimidazol-1-yl)pentanoic acid is a potent prodrug which may be bioreductively activated to a NOS inhibitor in hypoxic solid tumours.

  13. The energy-conserving nitric-oxide-reductase system in Paracoccus denitrificans. Distinction from the nitrite reductase that catalyses synthesis of nitric oxide and evidence from trapping experiments for nitric oxide as a free intermediate during denitrification.

    PubMed

    Carr, G J; Page, M D; Ferguson, S J

    1989-02-15

    1. A Clark-type electrode that responds to nitric oxide has been used to show that cytoplasmic membrane vesicles of Paracoccus denitrificans have a nitric-oxide reductase activity. Nitrous oxide is the reaction product. NADH, succinate or isoascorbate plus 2,3,5,6-tetramethyl-1,4-phenylene diamine can act as reductants. The NADH-dependent activity is resistant to freezing of the vesicles and thus the NADH:nitric-oxide oxidoreductase activity of stored frozen vesicles provides a method for calibrating the electrode by titration of dissolved nitric oxide with NADH. The periplasmic nitrite reductase and nitrous-oxide reductase enzymes are absent from the vesicles which indicates that nitric-oxide reductase is a discrete enzyme associated with the denitrification process. This conclusion was supported by the finding that nitric-oxide reductase activity was absent from both membranes prepared from aerobically grown P. denitrificans and bovine heart submitochondrial particles. 2. The NADH: nitric-oxide oxidoreductase activity was inhibited by concentrations of antimycin or myxothiazol that were just sufficient to inhibit the cytochrome bc1 complex of the ubiquinol--cytochrome-c oxidoreductase. The activity was deduced to be proton translocating by the observations of: (a) up to 3.5-fold stimulation upon addition of an uncoupler; and (b) ATP synthesis with a P:2e ratio of 0.75. 3. Nitrite reductase of cytochrome cd1 type was highly purified from P. denitrificans in a new, high-yield, rapid two- or three-step procedure. This enzyme catalysed stoichiometric synthesis of nitric oxide. This observation, taken together with the finding that the maximum rate of NADH:nitric-oxide oxidoreductase activity catalysed by the vesicles was comparable with that of NADH:nitrate-oxidoreductase, is consistent with a role for nitric-oxide reductase in the physiological conversion of nitrate or nitrite to dinitrogen gas. 4. Intact cells of P. denitrificans also reduced nitric oxide in an

  14. Genistein activates endothelial nitric oxide synthase in broiler pulmonary arterial endothelial cells by an Akt-dependent mechanism

    PubMed Central

    Yang, Ying; Nie, Wei; Yuan, Jianmin; Zhang, Bingkun; Wang, Zhong

    2010-01-01

    Deregulation of endothelial nitric oxide synthase (eNOS) plays an important role in the development of multiple cardiovascular diseases. Our recent study demonstrated that genistein supplementation attenuates pulmonary arterial hypertension in broilers by restoration of endothelial function. In this study, we investigated the molecular mechanism by using broiler pulmonary arterial endothelial cells (PAECs). Our results showed that genistein stimulated a rapid phosphorylation of eNOS at Ser1179 which was associated with activation of eNOS/NO axis. Further study indicated that the activation of eNOS was not mediated through estrogen receptors or tyrosine kinase inhibition, but via a phosphatidylinositol 3-kinase (PI3K)/Akt-dependent signaling pathway, as the eNOS activity and related NO release were largely abolished by pharmacological inhibitors of PI3K or Akt. Thus, our findings revealed a critical function of Akt in mediating genistein-stimulated eNOS activity in PAECs, partially accounting for the beneficial effects of genistein on the development of cardiovascular diseases observed in animal models. PMID:20926919

  15. Histochemical assessment of nitric oxide synthase activity in aortic endothelial cells of streptozotocin-induced diabetic rats.

    PubMed

    Shafiei, M; Nobakht, M; Fattahi, M; Kohneh-Shahri, L; Mahmoudian, M

    2003-12-01

    Impaired endothelium-dependent relaxation of blood vessels is a common feature in diabetes, but the exact underlying mechanisms have not yet been clarified. In present study, endothelium-dependent vasorelaxation of aortic rings were evaluated in vitro in streptozotocin (STZ)-induced diabetic and age-matched control rats. Moreover, nitric oxide synthase (NOS) activity of aortic endothelial cells was assessed in both diabetic and healthy rats using histochemical staining for nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase activity. The results showed a significant decrease of endothelium-dependent relaxation in response to acetylcholine (ACh) in diabetic rings, compared with controls, that was accompanied by a remarkable attenuation of NOS activity in diabetic sections of rat aorta stained for NADPH-diaphorase. Furthermore, a membrane disruption of some endothelial cells was also observed in all diabetic sections. It can be concluded that a decrease in NOS activity together with a disruption of endothelial cell membrane play a major role in endothelial dysfunction observed in diabetes.

  16. Endothelial nitric oxide synthase regulates N-Ras activation on the Golgi complex of antigen-stimulated T cells

    PubMed Central

    Ibiza, Sales; Pérez-Rodríguez, Andrea; Ortega, Ángel; Martínez-Ruiz, Antonio; Barreiro, Olga; García-Domínguez, Carlota A.; Víctor, Víctor M.; Esplugues, Juan V.; Rojas, José M.; Sánchez-Madrid, Francisco; Serrador, Juan M.

    2008-01-01

    Ras/ERK signaling plays an important role in T cell activation and development. We recently reported that endothelial nitric oxide synthase (eNOS)-derived NO regulates T cell receptor (TCR)-dependent ERK activation by a cGMP-independent mechanism. Here, we explore the mechanisms through which eNOS exerts this regulation. We have found that eNOS-derived NO positively regulates Ras/ERK activation in T cells stimulated with antigen on antigen-presenting cells (APCs). Intracellular activation of N-, H-, and K-Ras was monitored with fluorescent probes in T cells stably transfected with eNOS-GFP or its G2A point mutant, which is defective in activity and cellular localization. Using this system, we demonstrate that eNOS selectively activates N-Ras but not K-Ras on the Golgi complex of T cells engaged with APC, even though Ras isoforms are activated in response to NO from donors. We further show that activation of N-Ras involves eNOS-dependent S-nitrosylation on Cys118, suggesting that upon TCR engagement, eNOS-derived NO directly activates N-Ras on the Golgi. Moreover, wild-type but not C118S N-Ras increased TCR-dependent apoptosis, suggesting that S-nitrosylation of Cys118 contributes to activation-induced T cell death. Our data define a signaling mechanism for the regulation of the Ras/ERK pathway based on the eNOS-dependent differential activation of N-Ras and K-Ras at specific cell compartments. PMID:18641128

  17. Nitrite-dependent nitric oxide production pathway: implications for involvement of active nitrogen species in photoinhibition in vivo.

    PubMed

    Yamasaki, H

    2000-10-29

    Air pollution studies have shown that nitric oxide (NO), a gaseous free radical, is a potent photosynthetic inhibitor that reduces CO2 uptake activity in leaves. It is now recognized that NO is not only an air pollutant but also an endogenously produced metabolite, which may play a role in regulating plant cell functions. Although many studies have suggested the presence of mammalian-type NO synthase (NOS) in plants, the source of NO is still not clear. There has been a number of studies indicating that plant cells possess a nitrite-dependent NO production pathway which can be distinguished from the NOS-mediated reaction. Nitrate reductase (NR) has been recently found to be capable of producing NO through one-electron reduction of nitrite using NAD(P)H as an electron donor. This review focuses on current understanding of the mechanism for the nitrite-dependent NO production in plants. Impacts of NO produced by NR on photosynthesis are discussed in association with photo-oxidative stress in leaves.

  18. Hydrogen Peroxide–Mediated Activation of MAP Kinase 6 Modulates Nitric Oxide Biosynthesis and Signal Transduction in Arabidopsis[w

    PubMed Central

    Wang, Pengcheng; Du, Yanyan; Li, Yuan; Ren, Dongtao; Song, Chun-Peng

    2010-01-01

    Nitric oxide (NO) is a bioactive molecule that functions in numerous physiological and developmental processes in plants, including lateral root development. In this study, we used biochemical and genetic approaches to analyze the function of Arabidopsis thaliana mitogen-activated protein kinase 6 (MPK6) in the regulation of NO synthesis in response to hydrogen peroxide (H2O2) during lateral root development. In both mpk6 mutants studied, H2O2-induced NO synthesis and nitrate reductase (NR) activity were decreased dramatically. Furthermore, one NR isoform, NIA2, was required for the MPK6-mediated production of NO induced by H2O2. Notably, NIA2 interacted physically with MPK6 in vitro and in vivo and also served as a substrate of MPK6. Phosphorylation of NIA2 by MPK6 led to an increase in NR activity, and Ser-627 was identified as the putative phosphorylation site on NIA2. Phenotypical analysis revealed that mpk6-2 and mpk6-3 seedlings produce more and longer lateral roots than wild-type plants did after application of the NO donor sodium nitroprusside or H2O2. These data support strongly a function of MPK6 in modulating NO production and signal transduction in response to H2O2 during Arabidopsis root development. PMID:20870959

  19. Cerebral nitric oxide represses choroid plexus NFκB-dependent gateway activity for leukocyte trafficking

    PubMed Central

    Baruch, Kuti; Kertser, Alexander; Porat, Ziv; Schwartz, Michal

    2015-01-01

    Chronic neuroinflammation is evident in brain aging and neurodegenerative disorders and is often associated with excessive nitric oxide (NO) production within the central nervous system (CNS). Under such conditions, increased NO levels are observed at the choroid plexus (CP), an epithelial layer that forms the blood–cerebrospinal fluid barrier (BCSFB) and serves as a selective gateway for leukocyte entry to the CNS in homeostasis and following injury. Here, we hypothesized that elevated cerebral NO levels interfere with CP gateway activity. We found that induction of leukocyte trafficking determinants by the CP and sequential leukocyte entry to the CSF are dependent on the CP epithelial NFκB/p65 signaling pathway, which was inhibited upon exposure to NO. Examining the CP in 5XFAD transgenic mouse model of Alzheimer's disease (AD-Tg) revealed impaired ability to mount an NFκB/p65-dependent response. Systemic administration of an NO scavenger in AD-Tg mice alleviated NFκB/p65 suppression at the CP and augmented its gateway activity. Together, our findings identify cerebral NO as a negative regulator of CP gateway activity for immune cell trafficking to the CNS. PMID:25940071

  20. Exploration of the active site of neuronal nitric oxide synthase by the design and synthesis of pyrrolidinomethyl 2-aminopyridine derivatives.

    PubMed

    Ji, Haitao; Delker, Silvia L; Li, Huiying; Martásek, Pavel; Roman, Linda J; Poulos, Thomas L; Silverman, Richard B

    2010-11-11

    Neuronal nitric oxide synthase (nNOS) represents an important therapeutic target for the prevention of brain injury and the treatment of various neurodegenerative disorders. A series of trans-substituted amino pyrrolidinomethyl 2-aminopyridine derivatives (8-34) was designed and synthesized. A structure-activity relationship analysis led to the discovery of low nanomolar nNOS inhibitors ((±)-32 and (±)-34) with more than 1000-fold selectivity for nNOS over eNOS. Four enantiomerically pure isomers of 3'-[2''-(3'''-fluorophenethylamino)ethoxy]pyrrolidin-4'-yl}methyl}-4-methylpyridin-2-amine (4) also were synthesized. It was found that (3'R,4'R)-4 can induce enzyme elasticity to generate a new "hot spot" for ligand binding. The inhibitor adopts a unique binding mode, the same as that observed for (3'R,4'R)-3'-[2''-(3'''-fluorophenethylamino)ethylamino]pyrrolidin-4'-yl}methyl}-4-methylpyridin-2-amine ((3'R,4'R)-3) (J. Am. Chem. Soc. 2010, 132 (15), 5437 - 5442). On the basis of structure-activity relationships of 8-34 and different binding conformations of the cis and trans isomers of 3 and 4, critical structural requirements of the NOS active site for ligand binding are revealed.

  1. NOS1-derived nitric oxide promotes NF-κB transcriptional activity through inhibition of suppressor of cytokine signaling-1

    PubMed Central

    Baig, Mirza Saqib; Zaichick, Sofia V.; Mao, Mao; de Abreu, Andre L.; Bakhshi, Farnaz R.; Hart, Peter C.; Saqib, Uzma; Deng, Jing; Chatterjee, Saurabh; Block, Michelle L.; Vogel, Stephen M.; Malik, Asrar B.; Consolaro, Marcia E.L.; Christman, John W.; Minshall, Richard D.

    2015-01-01

    The NF-κB pathway is central to the regulation of inflammation. Here, we demonstrate that the low-output nitric oxide (NO) synthase 1 (NOS1 or nNOS) plays a critical role in the inflammatory response by promoting the activity of NF-κB. Specifically, NOS1-derived NO production in macrophages leads to proteolysis of suppressor of cytokine signaling 1 (SOCS1), alleviating its repression of NF-κB transcriptional activity. As a result, NOS1−/− mice demonstrate reduced cytokine production, lung injury, and mortality when subjected to two different models of sepsis. Isolated NOS1−/− macrophages demonstrate similar defects in proinflammatory transcription on challenge with Gram-negative bacterial LPS. Consistently, we found that activated NOS1−/− macrophages contain increased SOCS1 protein and decreased levels of p65 protein compared with wild-type cells. NOS1-dependent S-nitrosation of SOCS1 impairs its binding to p65 and targets SOCS1 for proteolysis. Treatment of NOS1−/− cells with exogenous NO rescues both SOCS1 degradation and stabilization of p65 protein. Point mutation analysis demonstrated that both Cys147 and Cys179 on SOCS1 are required for its NO-dependent degradation. These findings demonstrate a fundamental role for NOS1-derived NO in regulating TLR4-mediated inflammatory gene transcription, as well as the intensity and duration of the resulting host immune response. PMID:26324446

  2. Satellite cell activation in stretched skeletal muscle and the role of nitric oxide and hepatocyte growth factor.

    PubMed

    Tatsumi, Ryuichi; Liu, Xiaosong; Pulido, Antonio; Morales, Mark; Sakata, Tomowa; Dial, Sharon; Hattori, Akihito; Ikeuchi, Yoshihide; Allen, Ronald E

    2006-06-01

    In the present study, we examined the roles of hepatocyte growth factor (HGF) and nitric oxide (NO) in the activation of satellite cells in passively stretched rat skeletal muscle. A hindlimb suspension model was developed in which the vastus, adductor, and gracilis muscles were subjected to stretch for 1 h. Satellite cells were activated by stretch determined on the basis of 5-bromo-2'-deoxyuridine (BrdU) incorporation in vivo. Extracts from stretched muscles stimulated BrdU incorporation in freshly isolated control rat satellite cells in a concentration-dependent manner. Extracts from stretched muscles contained the active form of HGF, and the satellite cell-activating activity could be neutralized by incubation with anti-HGF antibody. The involvement of NO was investigated by administering nitro-L-arginine methyl ester (L-NAME) or the inactive enantiomer N(G)-nitro-D-arginine methyl ester HCl (D-NAME) before stretch treatment. In vivo activation of satellite cells in stretched muscle was not inhibited by D-NAME but was inhibited by L-NAME. The activity of stretched muscle extract was abolished by L-NAME treatment but could be restored by the addition of HGF, indicating that the extract was not inhibitory. Finally, NO synthase activity in stretched and unstretched muscles was assayed in muscle extracts immediately after 2-h stretch treatment and was found to be elevated in stretched muscle but not in stretched muscle from L-NAME-treated rats. The results of these experiments demonstrate that stretching muscle liberates HGF in a NO-dependent manner, which can activate satellite cells.

  3. [Progesterone and nitric oxide systems].

    PubMed

    Wieser, F; Gruber, D M; Tschugguel, W; Huber, J C

    1997-01-01

    Sexual steroids play an established role in the mechanisms concerning reproduction, ovulation, menstruation and onset of labour. However, sexual steroids are also involved in extragenital mechanisms, which were described for both oestrogen, and progesterone. Progesterone and its mechanisms of signal transduction still remain to be fully understood. However, there is evidence, that nitric oxide (NO) seems to be an important mediator in these mechanisms. NO, the molecule, which was described to exist in acid rain, was elected the molecule of the year 1992 from the American Academy of Science. NO is a short-lived molecule, which is involved in many reactions as an modulating transmitter due to its high diffusibility and its polarity. NO regulates the immune response of mononuclear cells, contractility of smooth muscle cells and neuronal transmission of non-adrenergic and non-cholinergic nerves. Additionally it was found, that NO may be important in the regulation of menstruation, the maintenance of uterine quiescence as well as the initiation of labour and the maturation of the uterine cervix.

  4. Nitric oxide regulates vascular adaptive mitochondrial dynamics.

    PubMed

    Miller, Matthew W; Knaub, Leslie A; Olivera-Fragoso, Luis F; Keller, Amy C; Balasubramaniam, Vivek; Watson, Peter A; Reusch, Jane E B

    2013-06-15

    Cardiovascular disease risk factors, such as diabetes, hypertension, dyslipidemia, obesity, and physical inactivity, are all correlated with impaired endothelial nitric oxide synthase (eNOS) function and decreased nitric oxide (NO) production. NO-mediated regulation of mitochondrial biogenesis has been established in many tissues, yet the role of eNOS in vascular mitochondrial biogenesis and dynamics is unclear. We hypothesized that genetic eNOS deletion and 3-day nitric oxide synthase (NOS) inhibition in rodents would result in impaired mitochondrial biogenesis and defunct fission/fusion and autophagy profiles within the aorta. We observed a significant, eNOS expression-dependent decrease in mitochondrial electron transport chain (ETC) protein subunits from complexes I, II, III, and V in eNOS heterozygotes and eNOS null mice compared with age-matched controls. In response to NOS inhibition with NG-nitro-L-arginine methyl ester (L-NAME) treatment in Sprague Dawley rats, significant decreases were observed in ETC protein subunits from complexes I, III, and IV as well as voltage-dependent anion channel 1. Decreased protein content of upstream regulators of mitochondrial biogenesis, cAMP response element-binding protein and peroxisome proliferator-activated receptor-γ coactivator-1α, were observed in response to 3-day L-NAME treatment. Both genetic eNOS deletion and NOS inhibition resulted in decreased manganese superoxide dismutase protein. L-NAME treatment resulted in significant changes to mitochondrial dynamic protein profiles with decreased fusion, increased fission, and minimally perturbed autophagy. In addition, L-NAME treatment blocked mitochondrial adaptation to an exercise intervention in the aorta. These results suggest that eNOS/NO play a role in basal and adaptive mitochondrial biogenesis in the vasculature and regulation of mitochondrial turnover. PMID:23585138

  5. Nitric oxide-activated hydrogen sulfide is essential for cadmium stress response in bermudagrass (Cynodon dactylon (L). Pers.).

    PubMed

    Shi, Haitao; Ye, Tiantian; Chan, Zhulong

    2014-01-01

    Nitric oxide (NO) and hydrogen sulfide (H2S) are important gaseous molecules, serving as important secondary messengers in plant response to various biotic and abiotic stresses. However, the interaction between NO and H2S in plant stress response was largely unclear. In this study, endogenous NO and H2S were evidently induced by cadmium stress treatment in bermudagrass, and exogenous applications of NO donor (sodium nitroprusside, SNP) or H2S donor (sodium hydrosulfide, NaHS) conferred improved cadmium stress tolerance. Additionally, SNP and NaHS treatments alleviated cadmium stress-triggered plant growth inhibition, cell damage and reactive oxygen species (ROS) burst, partly via modulating enzymatic and non-enzymatic antioxidants. Moreover, SNP and NaHS treatments also induced the productions of both NO and H2S in the presence of Cd. Interestingly, combined treatments with inhibitors and scavengers of NO and H2S under cadmium stress condition showed that NO signal could be blocked by both NO and H2S inhibitors and scavengers, while H2S signal was specifically blocked by H2S inhibitors and scavengers, indicating that NO-activated H2S was essential for cadmium stress response. Taken together, we assigned the protective roles of endogenous and exogenous NO and H2S in bermudagrass response to cadmium stress, and speculated that NO-activated H2S might be essential for cadmium stress response in bermudagrass.

  6. The volatile oil of Nardostachyos Radix et Rhizoma induces endothelial nitric oxide synthase activity in HUVEC cells.

    PubMed

    Maiwulanjiang, Maitinuer; Bi, Cathy W C; Lee, Pinky S C; Xin, Guizhong; Miernisha, Abudureyimu; Lau, Kei M; Xiong, Aizhen; Li, Ning; Dong, Tina T X; Aisa, Haji A; Tsim, Karl W K

    2015-01-01

    Nardostahyos Radix et Rhizoma (NRR; the root and rhizome of Nardostachys jatamansi DC.) is a widely used medicinal herb. Historically, NRR is being used for the treatment of cardiovascular and neurological diseases. To search for active ingredients of NRR, we investigated the vascular benefit of NRR volatile oil in (i) the vasodilation in rat aorta ring, and (ii) the release of nitric oxide (NO) and the phosphorylation of endothelial NO synthase (eNOS) in cultured human umbilical vein endothelial cells (HUVECs). By measuring the fluorescence signal in cultures, application of NRR volatile oil resulted in a rapid activation of NO release as well as the phosphorylation of eNOS: both inductions were markedly reduced by L-NAME. In parallel, the phosphorylation level of Akt kinase was markedly increased by the oil treatment, which was partially attenuated by PI3K/Akt inhibitor LY294002. This inhibitor also blocked the NRR-induced NO production and eNOS phosphorylation. In HUVECs, application of NRR volatile oil elevated the intracellular Ca(2+) level, and BAPTA-AM, a Ca(2+) chelator, reduced the Ca(2+) surge: the blockage were also applied to NRR-induced eNOS phosphorylation and NO production. These findings suggested the volatile oil of NRR was the major ingredient in triggering the vascular dilatation, and which was mediated via the NO production. PMID:25643147

  7. Nitric oxide mediates angiogenesis induced in vivo by platelet-activating factor and tumor necrosis factor-alpha.

    PubMed Central

    Montrucchio, G.; Lupia, E.; de Martino, A.; Battaglia, E.; Arese, M.; Tizzani, A.; Bussolino, F.; Camussi, G.

    1997-01-01

    We evaluated the role of an endogenous production of nitric oxide (NO) in the in vitro migration of endothelial cells and in the in vivo angiogenic response elicited by platelet-activating factor (PAF), tumor necrosis factor-alpha (TNF), and basic fibroblast growth factor (bFGF). The NO synthase inhibitor, N omega-nitro-L-arginine-methyl ester (L-NAME), but not its enantiomer D-NAME, prevented chemotaxis of endothelial cells induced in vitro by PAF and by TNF. The motogenic activity of TNF was also inhibited by WEB 2170, a specific PAF-receptor antagonist. In contrast, chemotaxis induced by bFGF was not prevented by L-NAME or by WEB 2170. Angiogenesis was studied in vivo in a murine model in which Matrigel was used as a vehicle for the delivery of mediators. In this model, the angiogenesis induced by PAF and TNF was inhibited by WEB 2170 and L-NAME but not by D-NAME. In contrast, angiogenesis induced by bFGF was not affected by L-NAME or by WEB 2170. TNF, but not bFGF, induced PAF synthesis within Matrigel. These results suggest that NO mediates the angiogenesis induced by PAF as well as that induced by TNF, which is dependent on the production of PAF. In contrast, the angiogenic effect of bFGF appears to be both PAF and NO independent. Images Figure 3 Figure 4 PMID:9250168

  8. The Volatile Oil of Nardostachyos Radix et Rhizoma Induces Endothelial Nitric Oxide Synthase Activity in HUVEC Cells

    PubMed Central

    Maiwulanjiang, Maitinuer; Bi, Cathy W. C.; Lee, Pinky S. C.; Xin, Guizhong; Miernisha, Abudureyimu; Lau, Kei M.; Xiong, Aizhen; Li, Ning; Dong, Tina T. X.; Aisa, Haji A.; Tsim, Karl W. K.

    2015-01-01

    Nardostahyos Radix et Rhizoma (NRR; the root and rhizome of Nardostachys jatamansi DC.) is a widely used medicinal herb. Historically, NRR is being used for the treatment of cardiovascular and neurological diseases. To search for active ingredients of NRR, we investigated the vascular benefit of NRR volatile oil in (i) the vasodilation in rat aorta ring, and (ii) the release of nitric oxide (NO) and the phosphorylation of endothelial NO synthase (eNOS) in cultured human umbilical vein endothelial cells (HUVECs). By measuring the fluorescence signal in cultures, application of NRR volatile oil resulted in a rapid activation of NO release as well as the phosphorylation of eNOS: both inductions were markedly reduced by L-NAME. In parallel, the phosphorylation level of Akt kinase was markedly increased by the oil treatment, which was partially attenuated by PI3K/Akt inhibitor LY294002. This inhibitor also blocked the NRR-induced NO production and eNOS phosphorylation. In HUVECs, application of NRR volatile oil elevated the intracellular Ca2+ level, and BAPTA-AM, a Ca2+ chelator, reduced the Ca2+ surge: the blockage were also applied to NRR-induced eNOS phosphorylation and NO production. These findings suggested the volatile oil of NRR was the major ingredient in triggering the vascular dilatation, and which was mediated via the NO production. PMID:25643147

  9. Caveolin-1 mediates endotoxin inhibition of endothelin-1-induced endothelial nitric oxide synthase activity in liver sinusoidal endothelial cells.

    PubMed

    Kwok, Willson; Lee, Sang Ho; Culberson, Cathy; Korneszczuk, Katarzyna; Clemens, Mark G

    2009-11-01

    Endothelin-1 (ET-1) plays a key role in the regulation of endothelial nitric oxide synthase (eNOS) activation in liver sinusoidal endothelial cells (LSECs). In the presence of endotoxin, an increase in caveolin-1 (Cav-1) expression impairs ET-1/eNOS signaling; however, the molecular mechanism is unknown. The objective of this study was to investigate the molecular mechanism of Cav-1 in the regulation of LPS suppression of ET-1-mediated eNOS activation in LSECs by examining the effect of caveolae disruption using methyl-beta-cyclodextrin (CD) and filipin. Treatment with 5 mM CD for 30 min increased eNOS activity (+255%, P < 0.05). A dose (0.25 microg/ml) of filipin for 30 min produced a similar effect (+111%, P < 0.05). CD induced the perinuclear localization of Cav-1 and eNOS and stimulated NO production in the same region. Readdition of 0.5 mM cholesterol to saturate CD reversed these effects. Both the combined treatment with CD and ET-1 (CD + ET-1) and with filipin and ET-1 stimulated eNOS activity; however, pretreatment with endotoxin (LPS) abrogated these effects. Following LPS pretreatment, CD + ET-1 failed to stimulate eNOS activity (+51%, P > 0.05), which contributed to the reduced levels of eNOS-Ser1177 phosphorylation and eNOS-Thr495 dephosphorylation, the LPS/CD-induced overexpression and translocation of Cav-1 in the perinuclear region, and the increased perinuclear colocalization of eNOS with Cav-1. These results supported the hypothesis that Cav-1 mediates the action of endotoxin in suppressing ET-1-mediated eNOS activation and demonstrated that the manipulation of caveolae produces significant effects on ET-1-mediated eNOS activity in LSECs.

  10. Stimulation of calcium-sensing receptors induces endothelium-dependent vasorelaxations via nitric oxide production and activation of IKCa channels

    PubMed Central

    Greenberg, Harry Z.E.; Shi, Jian; Jahan, Kazi S.; Martinucci, Matthew C.; Gilbert, Steven J.; Vanessa Ho, W.-S.; Albert, Anthony P.

    2016-01-01

    Stimulation of vascular calcium-sensing receptors (CaSRs) is reported to induce both constrictions and relaxations. However, cellular mechanisms involved in these responses remain unclear. The present study investigates the effect of stimulating CaSRs on vascular contractility and focuses on the role of the endothelium, nitric oxide (NO) and K+ channels in these responses. In wire myography studies, increasing [Ca2 +]o from 1 mM to 6 mM induced concentration-dependent relaxations of methoxamine pre-contracted rabbit mesenteric arteries. [Ca2 +]o-induced relaxations were dependent on a functional endothelium, and were inhibited by the negative allosteric CaSR modulator Calhex-231. [Ca2 +]o-induced relaxations were reduced by inhibitors of endothelial NO synthase, guanylate cyclase, and protein kinase G. CaSR activation also induced NO production in freshly isolated endothelial cells (ECs) in experiments using the fluorescent NO indicator DAF-FM. Pre-treatment with inhibitors of large (BKCa) and intermediate (IKCa) Ca2 +-activated K+ channels (iberiotoxin and charybdotoxin), and Kv7 channels (linopirdine) also reduced [Ca2 +]o-induced vasorelaxations. Increasing [Ca2 +]o also activated IKCa currents in perforated-patch recordings of isolated mesenteric artery ECs. These findings indicate that stimulation of CaSRs induces endothelium-dependent vasorelaxations which are mediated by two separate pathways involving production of NO and activation of IKCa channels. NO stimulates PKG leading to BKCa activation in vascular smooth muscle cells, whereas IKCa activity contributes to endothelium-derived hyperpolarisations. PMID:26772767

  11. CD18/ICAM-1-dependent oxidative NF-kappaB activation leading to nitric oxide production in rat Kupffer cells cocultured with syngeneic hepatoma cells.

    PubMed Central

    Kurose, I; Saito, H; Miura, S; Ebinuma, H; Higuchi, H; Watanabe, N; Zeki, S; Nakamura, T; Takaishi, M; Ishii, H

    1997-01-01

    Previous studies have indicated that nitric oxide (NO) released from Kupffer cells modulates biological viability of cocultured hepatoma cells. This study was designed to evaluate the mechanisms by which Kupffer cells synthesize and release NO in reponse to cocultured hepatoma cells. Kupffer cells isolated from male Wistar rats were cocultured with rat hepatoma cell line, AH70 cells. The sum of nitrite and nitrate levels increased in the culture medium of Kupffer cells with AH70 cells as compared with those of Kupffer cells or AH70 cells alone. Increased expressions of iNOS and iNOS mRNA in Kupffer cells cocultured with AH70 cells were detected by an immunofluorescence staining and a fluorescence in situ hybridization study, respectively. A fluorescence in situ DNA-protein binding assay revealed that NF-kappaB activation occurs in Kupffer cells and activated NF-kappaB moved into the nuclei preceding to an increased production of NO. Oxidative stress indicated by dichlorofluorescein fluorescence was observed in Kupffer cells cocultured with AH70 cells. An increased calcium mobilization indicated as increased fluo-3-associated fluorescence was also induced in Kupffer cells after coculture with AH70 cells. Monoclonal antibodies directed against rat CD18 and ICAM-1, as well as TMB-8, a calcium inhibitor, prevented the calcium mobilization, active oxygen production, and NF-kappaB activation in addition to the increased production of NO. Pyrrolidine dithiocarbamate, an inhibitor of oxidative NF-kappaB activation, diphenylene iodonium, an NADPH oxidase inhibitor, and quinacrine, a phospholipase A2 inhibitor, significantly attenuated the increase in dichlorofluorescein fluorescence, NF-kappaB activation, and NO production. Therefore, this study suggests that CD18/ICAM-1-dependent cell-to-cell interaction with hepatoma cells causes calcium mobilization and oxidative activation of NF-kappaB, which may lead to the increased production of NO in Kupffer cells. PMID:9062344

  12. Elucidation of Danzhixiaoyao Wan and Its Constituent Herbs on Antioxidant Activity and Inhibition of Nitric Oxide Production

    PubMed Central

    Banbury, Linda K.; Leach, David N.

    2007-01-01

    Danzhixiaoyao Wan (DW) is a common 10 herbs formulation in China for regulating several clinical conditions affecting women. This research tried to explain one of DW's functions, purging heat, using in vitro pharmacological analyses. The whole formulation and each single herb of DW were compared based on antioxidant activity with the oxygen radical absorbance capacity (ORAC) assay, and for their inhibitory effect (IE) on nitric oxide (NO) production by lipopolysaccharide (LPS)-activated RAW 264.7 macrophages with the Griess assay. The results showed that DW as a whole formulation had both antioxidant activity and an IE on NO production, while the individual herb component of DW varied in their ORAC values and inhibition of NO production. The ORAC value of the whole DW was 450 μmol TE g−1. The order of antioxidant (ORAC) activity of the single herbs was: Mentha haplocalyx (1352 μmol TE g−1) > Glycyrrhiza uralensis (1184 μmol TE g−1) > Gardenia jasminoides (1129 μmol TE g−1) > Paeonia suffruticosa (465 μmol TE g−1), with the contributions being additive rather than synergistic. The production of nitrite by stimulated RAW 264.7 murine macrophages (unstimulated: 0.5 ± 0.1 μM versus LPS: 38.9 ± 2.3 μM) was significantly inhibited (P < 0.05) by M. haplocalyx, G. jasminoides, Bupleurum chinense and Paeonia lactiflora. DW as a whole had an IE on NO production, but this was not significant. The single herb M. haplocalyx had the highest ORAC value and the highest IE on NO production, followed by G. jasminoides. Both of these herbs have the ‘purging heat’ property in the theory of traditional Chinese medicine and this property of the samples may be correlated with the antioxidant activity and IE on NO production. PMID:18227909

  13. Generation of nitric oxide from nitrite by carbonic anhydrase: a possible link between metabolic activity and vasodilation.

    PubMed

    Aamand, Rasmus; Dalsgaard, Thomas; Jensen, Frank B; Simonsen, Ulf; Roepstorff, Andreas; Fago, Angela

    2009-12-01

    In catalyzing the reversible hydration of CO2 to bicarbonate and protons, the ubiquitous enzyme carbonic anhydrase (CA) plays a crucial role in CO2 transport, in acid-base balance, and in linking local acidosis to O2 unloading from hemoglobin. Considering the structural similarity between bicarbonate and nitrite, we hypothesized that CA uses nitrite as a substrate to produce the potent vasodilator nitric oxide (NO) to increase local blood flow to metabolically active tissues. Here we show that CA readily reacts with nitrite to generate NO, particularly at low pH, and that the NO produced in the reaction induces vasodilation in aortic rings. This reaction occurs under normoxic and hypoxic conditions and in various tissues at physiological levels of CA and nitrite. Furthermore, two specific inhibitors of the CO2 hydration, dorzolamide and acetazolamide, increase the CA-catalyzed production of vasoactive NO from nitrite. This enhancing effect may explain the known vasodilating effects of these drugs and indicates that CO2 and nitrite bind differently to the enzyme active site. Kinetic analyses show a higher reaction rate at high pH, suggesting that anionic nitrite participates more effectively in catalysis. Taken together, our results reveal a novel nitrous anhydrase enzymatic activity of CA that would function to link the in vivo main end products of energy metabolism (CO2/H+) to the generation of vasoactive NO. The CA-mediated NO production may be important to the correlation between blood flow and metabolic activity in tissues, as occurring for instance in active areas of the brain. PMID:19820197

  14. Exogenous nitric oxide inhibits Rho-associated kinase activity in patients with angina pectoris: a randomized controlled trial.

    PubMed

    Maruhashi, Tatsuya; Noma, Kensuke; Fujimura, Noritaka; Kajikawa, Masato; Matsumoto, Takeshi; Hidaka, Takayuki; Nakashima, Ayumu; Kihara, Yasuki; Liao, James K; Higashi, Yukihito

    2015-07-01

    The RhoA/Rho-associated kinase (ROCK) pathway has a key physiological role in the pathogenesis of atherosclerosis. Increased ROCK activity is associated with cardiovascular diseases. Endogenous nitric oxide (NO) has an anti-atherosclerotic effect, whereas the exogenous NO-mediated cardiovascular effect still remains controversial. The purpose of this study was to evaluate the effect of exogenous NO on ROCK activity in patients with angina pectoris. This is a prospective, open-label, randomized, controlled study. A total of 30 patients with angina pectoris were randomly assigned to receive 40 mg day(-1) of isosorbide mononitrate (n=15, 12 men and 3 women, mean age of 63±12 years, isosorbide mononitrate group) or conventional treatment (n=15, 13 men and 2 women, mean age of 64±13 years, control group) for 12 weeks. ROCK activity in peripheral leukocytes was measured by western blot analysis. ROCK activities at 4 and 12 weeks after treatment were decreased in the isosorbide mononitrate group (0.82±0.33 at 0 week, 0.62±0.20 at 4 weeks, 0.61±0.19 at 12 weeks, n=15 in each group, P<0.05, respectively) but not altered in the control group. ROCK1 and ROCK2 expression levels were similar in all treatment periods in the two groups. These findings suggest that the administration of exogenous NO can inhibit ROCK activity, indicating that the usage of exogenous NO could have a protective effect in patients with angina pectoris.

  15. Remote ischemia preconditioning increases red blood cell deformability through red blood cell-nitric oxide synthase activation.

    PubMed

    Grau, Marijke; Kollikowski, Alexander; Bloch, Wilhelm

    2016-09-12

    Remote ischemia preconditioning (rIPC), short cycles of ischemia (I) and reperfusion (R) of a region remote from the heart, protects against myocardial I/R injury. This effect is triggered by endothelial derived nitric oxide (NO) production. Red blood cells (RBC) are also capable of NO production and it is hypothesized that the beneficial effect of rIPC in terms of cardioprotection is strengthened by increased RBC dependent NO production and improved RBC function after rIPC maneuver. For this purpose, twenty male participants were subjected to four cycles of no-flow ischemia with subsequent reactive hyperemia within the forearm. Blood sampling and measurement of blood pressures and heart rate were carried out pre intervention, after each cycle and 15 min post intervention at both the non-treated and treated arm. These are the first results that show improved RBC deformability in the treated arm after rIPC cycles 1- 4 caused by significantly increased RBC-NO synthase activation. This in turn was associated to increased NO production in both arms after rIPC cycles 3 + 4. Also, systolic and diastolic blood pressures were decreased after rIPC. The findings lead to the conclusion that the cardioprotective effects associated with rIPC include improvement of the RBC-NOS/NO signaling in RBC.

  16. Fo Shou San, an Ancient Chinese Herbal Decoction, Protects Endothelial Function through Increasing Endothelial Nitric Oxide Synthase Activity

    PubMed Central

    Bi, Cathy W. C.; Xu, Li; Tian, Xiao Yu; Liu, Jian; Zheng, Ken Y. Z.; Lau, Chi Wai; Lau, David T. W.; Choi, Roy C. Y.; Dong, Tina T. X.; Huang, Yu; Tsim, Karl W. K.

    2012-01-01

    Fo Shou San (FSS) is an ancient herbal decoction comprised of Chuanxiong Rhizoma (CR; Chuanxiong) and Angelicae Sinensis Radix (ASR; Danggui) in a ratio of 2∶3. Previous studies indicate that FSS promotes blood circulation and dissipates blood stasis, thus which is being used widely to treat vascular diseases. Here, we aim to determine the cellular mechanism for the vascular benefit of FSS. The treatment of FSS reversed homocysteine-induced impairment of acetylcholine (ACh)-evoked endothelium-dependent relaxation in aortic rings, isolated from rats. Like radical oxygen species (ROS) scavenger tempol, FSS attenuated homocysteine-stimulated ROS generation in cultured human umbilical vein endothelial cells (HUVECs), and it also stimulated the production of nitric oxide (NO) as measured by fluorescence dye and biochemical assay. In addition, the phosphorylation levels of both Akt kinase and endothelial NO synthases (eNOS) were markedly increased by FSS treatment, which was abolished by an Akt inhibitor triciribine. Likewise, triciribine reversed FSS-induced NO production in HUVECs. Finally, FSS elevated intracellular Ca2+ levels in HUVECs, and the Ca2+ chelator BAPTA-AM inhibited the FSS-stimulated eNOS phosphorylation. The present results show that this ancient herbal decoction benefits endothelial function through increased activity of Akt kinase and eNOS; this effect is causally via a rise of intracellular Ca2+ and a reduction of ROS. PMID:23284736

  17. Vascular nitric oxide: Beyond eNOS.

    PubMed

    Zhao, Yingzi; Vanhoutte, Paul M; Leung, Susan W S

    2015-10-01

    As the first discovered gaseous signaling molecule, nitric oxide (NO) affects a number of cellular processes, including those involving vascular cells. This brief review summarizes the contribution of NO to the regulation of vascular tone and its sources in the blood vessel wall. NO regulates the degree of contraction of vascular smooth muscle cells mainly by stimulating soluble guanylyl cyclase (sGC) to produce cyclic guanosine monophosphate (cGMP), although cGMP-independent signaling [S-nitrosylation of target proteins, activation of sarco/endoplasmic reticulum calcium ATPase (SERCA) or production of cyclic inosine monophosphate (cIMP)] also can be involved. In the blood vessel wall, NO is produced mainly from l-arginine by the enzyme endothelial nitric oxide synthase (eNOS) but it can also be released non-enzymatically from S-nitrosothiols or from nitrate/nitrite. Dysfunction in the production and/or the bioavailability of NO characterizes endothelial dysfunction, which is associated with cardiovascular diseases such as hypertension and atherosclerosis. PMID:26499181

  18. [6]-Gingerol inhibits nitric oxide synthesis in activated J774.1 mouse macrophages and prevents peroxynitrite-induced oxidation and nitration reactions.

    PubMed

    Ippoushi, Katsunari; Azuma, Keiko; Ito, Hidekazu; Horie, Hideki; Higashio, Hisao

    2003-11-14

    Reactive nitrogen species (RNS), such as nitric oxide (NO) and its derivatives, e.g. peroxynitrite (ONOO-), have been proposed as being able to influence signal transduction and cause DNA damage, contributing to carcinogenic processes. In this study, the effect of [6]-gingerol, a pungent phenolic compound present in ginger (Zingiber officinale Roscoe), on NO synthesis in lipopolysaccharide (LPS)-activated J774.1 macrophages was tested, and the protective ability of this compound against peroxynitrite-mediated oxidation and nitration reactions were evaluated. [6]-Gingerol exhibited dose-dependent inhibition of NO production and significant reduction of inducible NO synthase (iNOS) in LPS-stimulated J774.1 cells. Moreover, [6]-gingerol effectively suppressed peroxynitrite-induced oxidation of dichlorodihydrofluorescein, oxidative single strand breaks in supercoiled pTZ 18U plasmid DNA, and formation of 3-nitrotyrosine in bovine serum albumin (BSA) and J774.1 cells. Our results indicate that [6]-gingerol is a potent inhibitor of NO synthesis and also an effective protector against peroxynitrite-mediated damage. PMID:14572883

  19. Modulation of Kv3 potassium channels expressed in CHO cells by a nitric oxide-activated phosphatase

    PubMed Central

    Moreno, Herman; de Miera, Eleazar Vega-Saenz; Nadal, Marcela S; Amarillo, Yimy; Rudy, Bernardo

    2001-01-01

    Voltage-gated K+ channels containing Kv3 subunits play specific roles in the repolarization of action potentials. Kv3 channels are expressed in selective populations of CNS neurons and are thought to be important in facilitating sustained and/or repetitive high frequency firing. Regulation of the activity of Kv3 channels by neurotransmitters could have profound effects on the repetitive firing characteristics of those neurons. Kv3 channels are found in several neuronal populations in the CNS that express nitric oxide synthases (NOSs). We therefore investigated whether Kv3 channels are modulated by the signalling gas nitric oxide (NO). We found that Kv3.1 and Kv3.2 currents are potentially suppressed by D-NONOate and other NO donors. The effects of NO on these currents are mediated by the activation of guanylyl cyclase (GC), since they are prevented by Methylene Blue, an inhibitor of GC, and by ODQ, a specific inhibitor of the soluble form of GC. Moreover, application of 8-Br-cGMP, a permeant analogue of cGMP, also blocked Kv3.1 and Kv3.2 currents. KT5283, a cGMP-dependent protein kinase (PKG) blocker, prevented the inhibition of Kv3.1 and Kv3.2 currents by D-NONOate and 8-Br-cGMP. This indicates that activation of PKG as a result of the increase in intracellular cGMP levels produced by D-NONOate or 8-Br-cGMP is necessary for channel block. Although the effects of NO on Kv3.1 and Kv3.2 channels require PKG activity, two observations suggest that they are not mediated by phosphorylation of channel proteins: (a) the reagents affect both Kv3.2 and Kv3.1 channels, although only Kv3.2 proteins have a putative PKA-PKG phosphorylation site, and (b) mutation of the PKA-PKG phosphorylation site in Kv3.2 does not interfere with the effects of NO or cGMP. The inhibitory effects of NO and cGMP on Kv3.1 and Kv3.2 currents appear to be mediated by the activation of serine-threonine phosphatase, since they are blocked by low doses of okadaic acid. Furthermore, direct intracellular

  20. Protection by Nitric Oxide Donors of Isolated Rat Hearts Is Associated with Activation of Redox Metabolism and Ferritin Accumulation

    PubMed Central

    Grievink, Hilbert; Zeltcer, Galina; Drenger, Benjamin; Berenshtein, Eduard; Chevion, Mordechai

    2016-01-01

    Preconditioning (PC) procedures (ischemic or pharmacological) are powerful procedures used for attaining protection against prolonged ischemia and reperfusion (I/R) injury, in a variety of organs, including the heart. The detailed molecular mechanisms underlying the protection by PC are however, complex and only partially understood. Recently, an ‘iron-based mechanism’ (IBM), that includes de novo ferritin synthesis and accumulation, was proposed to explain the specific steps in cardioprotection generated by IPC. The current study investigated whether nitric oxide (NO), generated by exogenous NO-donors, could play a role in the observed IBM of cardioprotection by IPC. Therefore, three distinct NO-donors were investigated at different concentrations (1–10 μM): sodium nitroprusside (SNP), 3-morpholinosydnonimine (SIN-1) and S-nitroso-N-acetylpenicillamine (SNAP). Isolated rat hearts were retrogradely perfused using the Langendorff configuration and subjected to prolonged ischemia and reperfusion with or without pretreatment by NO-donors. Hemodynamic parameters, infarct sizes and proteins of the methionine-centered redox cycle (MCRC) were analyzed, as well as cytosolic aconitase (CA) activity and ferritin protein levels. All NO-donors had significant effects on proteins involved in the MCRC system. Nonetheless, pretreatment with 10 μM SNAP was found to evoke the strongest effects on Msr activity, thioredoxin and thioredoxin reductase protein levels. These effects were accompanied with a significant reduction in infarct size, increased CA activity, and ferritin accumulation. Conversely, pretreatment with 2 μM SIN-1 increased infarct size and was associated with slightly lower ferritin protein levels. In conclusion, the abovementioned findings indicate that NO, depending on its bio-active redox form, can regulate iron metabolism and plays a role in the IBM of cardioprotection against reperfusion injury. PMID:27447933

  1. Protection by Nitric Oxide Donors of Isolated Rat Hearts Is Associated with Activation of Redox Metabolism and Ferritin Accumulation.

    PubMed

    Grievink, Hilbert; Zeltcer, Galina; Drenger, Benjamin; Berenshtein, Eduard; Chevion, Mordechai

    2016-01-01

    Preconditioning (PC) procedures (ischemic or pharmacological) are powerful procedures used for attaining protection against prolonged ischemia and reperfusion (I/R) injury, in a variety of organs, including the heart. The detailed molecular mechanisms underlying the protection by PC are however, complex and only partially understood. Recently, an 'iron-based mechanism' (IBM), that includes de novo ferritin synthesis and accumulation, was proposed to explain the specific steps in cardioprotection generated by IPC. The current study investigated whether nitric oxide (NO), generated by exogenous NO-donors, could play a role in the observed IBM of cardioprotection by IPC. Therefore, three distinct NO-donors were investigated at different concentrations (1-10 μM): sodium nitroprusside (SNP), 3-morpholinosydnonimine (SIN-1) and S-nitroso-N-acetylpenicillamine (SNAP). Isolated rat hearts were retrogradely perfused using the Langendorff configuration and subjected to prolonged ischemia and reperfusion with or without pretreatment by NO-donors. Hemodynamic parameters, infarct sizes and proteins of the methionine-centered redox cycle (MCRC) were analyzed, as well as cytosolic aconitase (CA) activity and ferritin protein levels. All NO-donors had significant effects on proteins involved in the MCRC system. Nonetheless, pretreatment with 10 μM SNAP was found to evoke the strongest effects on Msr activity, thioredoxin and thioredoxin reductase protein levels. These effects were accompanied with a significant reduction in infarct size, increased CA activity, and ferritin accumulation. Conversely, pretreatment with 2 μM SIN-1 increased infarct size and was associated with slightly lower ferritin protein levels. In conclusion, the abovementioned findings indicate that NO, depending on its bio-active redox form, can regulate iron metabolism and plays a role in the IBM of cardioprotection against reperfusion injury. PMID:27447933

  2. Coagulase-Negative Staphylococci Favor Conversion of Arginine into Ornithine despite a Widespread Genetic Potential for Nitric Oxide Synthase Activity

    PubMed Central

    Sánchez Mainar, María; Weckx, Stefan

    2014-01-01

    Within ecosystems that are poor in carbohydrates, alternative substrates such as arginine may be of importance to coagulase-negative staphylococci (CNS). However, the versatility of arginine conversion in CNS remains largely uncharted. Therefore, a set of 86 strains belonging to 17 CNS species was screened for arginine deiminase (ADI), arginase, and nitric oxide synthase (NOS) activities, in view of their ecological relevance. In fermented meats, for instance, ADI could improve bacterial competitiveness, whereas NOS may serve as an alternative nitrosomyoglobin generator to nitrate and nitrite curing. About 80% of the strains were able to convert arginine, but considerable inter- and intraspecies heterogeneity regarding the extent and mechanism of conversion was found. Overall, ADI was the most commonly employed pathway, resulting in mixtures of ornithine and small amounts of citrulline. Under aerobic conditions, which are more relevant for skin-associated CNS communities, several strains shifted toward arginase activity, leading to the production of ornithine and urea. The obtained data indeed suggest that arginase occurs relatively more in CNS isolates from a dairy environment, whereas ADI seems to be more abundant in strains from a fermented meat background. With some exceptions, a reasonable match between phenotypic ADI and arginase activity and the presence of the encoding genes (arcA and arg) was found. With respect to the NOS pathway, however, only one strain (Staphylococcus haemolyticus G110) displayed phenotypic NOS-like activity under aerobic conditions, despite a wide prevalence of the NOS-encoding gene (nos) among CNS. Hence, the group of CNS displays a strain- and condition-dependent toolbox of arginine-converting mechanisms with potential implications for competitiveness and functionality. PMID:25281381

  3. iNOS-Derived Nitric Oxide Stimulates Osteoclast Activity and Alveolar Bone Loss in Ligature-Induced Periodontitis in Rats

    PubMed Central

    Herrera, Bruno S.; Martins-Porto, Rodrigo; Maia-Dantas, Aline; Campi, Paula; Spolidorio, Luis C.; Costa, Soraia K.P.; Van Dyke, Thomas E.; Gyurko, Robert; Muscara, Marcelo N.

    2012-01-01

    Background Inflammatory stimuli activate inducible nitric oxide synthase (iNOS) in a variety of cell types, including osteoclasts (OC) and osteoblasts, resulting in sustained NO production. In this study, we evaluate the alveolar bone loss in rats with periodontitis under long-term iNOS inhibition, and the differentiation and activity of OC from iNOS-knockout (KO) mice in vitro. Methods Oral aminoguanidine (an iNOS inhibitor) or water treatment was started 2 weeks before induction of periodontitis. Rats were sacrificed 3, 7, or 14 days after ligature placement, and alveolar bone loss was evaluated. In vitro OC culture experiments were also performed to study the differentiation of freshly isolated bone marrow cells from both iNOS KO and wild-type C57BL/6 mice. OC were counted 6 days later after tartrate-resistant acid phosphatase staining (a marker of osteoclast identity), and bone resorption activity was assessed by counting the number of resorption pits on dentin disks. Results Rats with ligature showed progressive and significant alveolar bone loss compared to sham animals, and aminoguanidine treatment significantly inhibited ligature-induced bone loss at 7 and 14 days after the induction. In comparison to bone marrow cells from wild-type mice, cells from iNOS KO mice showed decreased OC growth and the resulting OC covered a smaller culture dish area and generated fewer resorption pit counts. Conclusion Our results demonstrate that iNOS inhibition prevents alveolar bone loss in a rat model of ligature-induced periodontitis, thus confirming that iNOS-derived NO plays a crucial role in the pathogenesis of periodontitis, probably by stimulating OC differentiation and activity. PMID:21417589

  4. Nitric oxide regulation of monkey myometrial contractility

    PubMed Central

    Kuenzli, Karri A; Buxton, Iain L O; Bradley, Michael E

    1998-01-01

    We evaluated the effect of the nitric oxide (NO) donor CysNO (S-nitroso-L-cysteine) and endogenous NO upon spontaneous contractility in non-pregnant cynomolgus monkeys. We also assessed the role of intracellular guanosine 3′,5′-cyclic monophosphate ([cyclic GMP]i) as a second messenger for NO in monkey uterine smooth muscle.CysNO reduced spontaneous contractility by 84% (P<0.05) at maximal concentrations, and significantly elevated [cyclic GMP]i (P<0.05). However, increases in [cyclic GMP]i were not required for CysNO-induced relaxations; CysNO inhibited contractile activity despite the complete inhibition of guanylyl cyclase by methylene blue or LY83,583.Analogues of cyclic GMP had no significant effect upon spontaneous contractile activity. L-arginine produced a 62% reduction in spontaneous activity (P<0.05) while D-arginine had no effect. The competitive nitric oxide synthase (NOS) inhibitor Nω-nitro-L-arginine (L-NOARG) not only blocked L-arginine-induced relaxations, but also significantly increased spontaneous contractile activity when added alone (P<0.05); the inactive D-enantiomer of NOARG had no such effect.While both endogenous NO and the NO donor CysNO relax monkey myometrium, this effect is not causally related to CysNO-induced elevations in [cyclic GMP]i. The failure of cyclic GMP analogues to alter monkey uterine smooth muscle tension also argues against a role for [cyclic GMP]i in the regulation of uterine contractility. Not only do these findings argue for the existence of a functionally-relevant NOS in the monkey uterus, but increases in contractile activity seen in the presence of NOS inhibitors suggest a role for NO in the moment-to-moment regulation of contractile activity in this organ. PMID:9630344

  5. Nitric oxide synthase activity in blood vessels of spontaneously hypertensive rats: antioxidant protection by gamma-tocotrienol.

    PubMed

    Newaz, M A; Yousefipour, Z; Nawal, N; Adeeb, N

    2003-09-01

    Involvement of free radicals and nitric oxide (NO) has long been implicated to the pathogenesis of essential hypertension. Several studies using antioxidants as the radical scavenger have shown to confer protection against free radical mediated diseases. This study is designed to investigate the role of antioxidant gamma-tocotrienol on endothelial nitric oxide synthase (NOS) activity in spontaneously hypertensive rats (SHR). SHR's were divided into four groups namely untreated SHR (HC), treatment with 15 mg gamma-tocotrienol/kg diet (gammal), 30 mg gamma-tocotrienol/kg diet (gamma2) and 150 mg gamma-tocotrienol/kg diet (gamma3) and studied for three months. Wister Kyoto (WKY) rats were used as the control (C). Blood pressure was recorded every fortnightly by tail plethysmography. Animals were sacrificed and NOS activity in blood vessels was measured by [3H]arginine radioactive assay. Nitrite concentration in plasma was determined by Greis assay and lipid peroxides in the blood vessels by spectrofluorometry. This study showed that gamma-tocotrienol significantly reduced systolic blood pressure (SBP) in SHRs with a maximum reduction in group treated with gamma-tocotrienol 15 mg/kg diet (HC: 210 +/- 9 mmHg, gammal:123 +/- 19 mmHg). Blood vessels from untreated SHR showed a reduced NOS activity compare to that of WKY rats (C: 1.54 +/- 0.26 pmol/mg protein, HC: 0.87 +/- 0.23 pmol/mg protein; p<0.001). Gamma-tocotrienol improves NOS activity in all the groups with more significance in group gamma2 (p<0.001) and gamma3 (p<0.05). Plasma level of nitrite was reduced in SHR from 55 +/- 3 microM/ml in WKY to 26+/-2 muM/ml (p<0.001). Plasma nitrite level was reversed by treatment with gamma-tocotrienol. (gammal: p<0.001, gamma2: p<0.005, gamma3: p<0.001, respectively). In all the treatment groups, NOS activity showed significant negative correlation with blood pressure (gammal: r=-0.716, p<0.05; gamma2: r=-0.709, p<0.05; gamma3: r=-0.789, p<0.05). For plasma nitrite, although

  6. Interleukin-12 gene-expression of macrophages is regulated by nitric oxide.

    PubMed

    Rothe, H; Hartmann, B; Geerlings, P; Kolb, H

    1996-07-01

    Interleukin-12 is a heterodimeric cytokine, mainly produced by macrophages. In our present study we demonstrate that interleukin-12 expression is regulated by nitric oxide. Incubation of the macrophage cell line IC 21 with interferon-gamma gave rise to both interleukin-12 p40 mRNA and nitric oxide production. The concurrent addition of the nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine inhibited nitrite production and in parallel completely suppressed interleukin-12 p40 mRNA formation. This indicated that endogenous nitric oxide synthase activity was required for IL-12 p40 gene expression. Exposure of the cells towards the nitric oxide generating compounds nitroprusside or S-nitroso-N-acetyl-penicillamine induced interleukin-12 p40 mRNA. Maximal mRNA levels were induced with nitric oxide donors at 1 microM concentration. We conclude that nitric oxide may exert an autoregulatory and paracrine control of interleukin-12 gene expression. PMID:8694804

  7. Neural mechanisms in nitric-oxide-deficient hypertension

    NASA Technical Reports Server (NTRS)

    Sander, M.; Victor, R. G.; Blomqvist, C. G. (Principal Investigator)

    1999-01-01

    Nitric oxide is hypothesized to be an inhibitory modulator of central sympathetic nervous outflow, and deficient neuronal nitric oxide production to cause sympathetic overactivity, which then contributes to nitric-oxide-deficient hypertension. The biochemical and neuroanatomical basis for this concept revolves around nitric oxide modulation of glutamatergic neurotransmission within brainstem vasomotor centers. The functional consequence of neuronal nitric oxide in blood pressure regulation is, however, marked by an apparent conflict in the literature. On one hand, conscious animal studies using sympathetic blockade suggest a significant role for neuronal nitric oxide deficiency in the development of nitric-oxide-deficient hypertension, and on the other hand, there is evidence against such a role derived from 'knock-out' mice lacking nitric-oxide synthase 1, the major source of neuronal nitric oxide.

  8. Puerarin activates endothelial nitric oxide synthase through estrogen receptor-dependent PI3-kinase and calcium-dependent AMP-activated protein kinase

    SciTech Connect

    Hwang, Yong Pil; Kim, Hyung Gyun; Hien, Tran Thi; Jeong, Myung Ho; Jeong, Tae Cheon; Jeong, Hye Gwang

    2011-11-15

    The cardioprotective properties of puerarin, a natural product, have been attributed to the endothelial nitric oxide synthase (eNOS)-mediated production of nitric oxide (NO) in EA.hy926 endothelial cells. However, the mechanism by which puerarin activates eNOS remains unclear. In this study, we sought to identify the intracellular pathways underlying eNOS activation by puerarin. Puerarin induced the activating phosphorylation of eNOS on Ser1177 and the production of NO in EA.hy926 cells. Puerarin-induced eNOS phosphorylation required estrogen receptor (ER)-mediated phosphatidylinositol 3-kinase (PI3K)/Akt signaling and was reversed by AMP-activated protein kinase (AMPK) and calcium/calmodulin-dependent kinase II (CaMKII) inhibition. Importantly, puerarin inhibited the adhesion of tumor necrosis factor (TNF)-{alpha}-stimulated monocytes to endothelial cells and suppressed the TNF-{alpha} induced expression of intercellular cell adhesion molecule-1. Puerarin also inhibited the TNF-{alpha}-induced nuclear factor-{kappa}B activation, which was attenuated by pretreatment with N{sup G}-nitro-L-arginine methyl ester, a NOS inhibitor. These results indicate that puerarin stimulates eNOS phosphorylation and NO production via activation of an estrogen receptor-mediated PI3K/Akt- and CaMKII/AMPK-dependent pathway. Puerarin may be useful for the treatment or prevention of endothelial dysfunction associated with diabetes and cardiovascular disease. -- Highlights: Black-Right-Pointing-Pointer Puerarin induced the phosphorylation of eNOS and the production of NO. Black-Right-Pointing-Pointer Puerarin activated eNOS through ER-dependent PI3-kinase and Ca{sup 2+}-dependent AMPK. Black-Right-Pointing-Pointer Puerarin-induced NO was involved in the inhibition of NF-kB activation. Black-Right-Pointing-Pointer Puerarin may help for prevention of vascular dysfunction and diabetes.

  9. Polymeric Coatings that Mimic the Endothelium: Combining Nitric Oxide Release with Surface-Bound Active Thrombomodulin and Heparin

    PubMed Central

    Wu, Biyun; Gerlitz, Bruce; Grinnell, Brian W.; Meyerhoff, Mark E.

    2007-01-01

    Multi-functional bilayer polymeric coatings are prepared with both controlled nitric oxide (NO) release and surface-bound active thrombomodulin (TM) alone or in combination with immobilized heparin. The outer-layer is made of CarboSil, a commercially available copolymer of silicone rubber (SR) and polyurethane (PU). The CarboSil is either carboxylated or aminated via an allophanate reaction with a diisocyanate compound followed by a urea-forming reaction between the generated isocyanate group of the polymer and the amine group of an amino acid (glycine), an oligopeptide (triglycine) or a diamine. The carboxylated CarboSil can then be used to immobilize TM through the formation of an amide bond between the surface carboxylic acid groups and the lysine residues of TM. Aminated CarboSil can also be employed to initially couple heparin to the surface, and then the carboxylic acid groups on heparin can be further used to anchor TM. Both surface-bound TM and heparin’s activity are evaluated by chromogenic assays and found to be at clinically significant levels. The underlying NO release layer is made with another commercial SR-PU copolymer (PurSil) mixed with a lipophilic NO donor (N-diazeniumdiolated dibutylhexanediamine (DBHD/N2O2)). The NO release rate can be tuned by changing the thickness of top coatings, and the duration of NO release at physiologically relevant levels can be as long as 2 weeks. The combination of controlled NO release as well as immobilized active TM and heparin from/on the same polymeric surface mimics the highly thromboresistant endothelium layer. Hence, such multifunctional polymer coatings should provide more blood-compatible surfaces for biomedical devices. PMID:17597201

  10. Nitric oxide and mitochondria in metabolic syndrome

    PubMed Central

    Litvinova, Larisa; Atochin, Dmitriy N.; Fattakhov, Nikolai; Vasilenko, Mariia; Zatolokin, Pavel; Kirienkova, Elena

    2015-01-01

    Metabolic syndrome (MS) is a cluster of metabolic disorders that collectively increase the risk of cardiovascular disease. Nitric oxide (NO) plays a crucial role in the pathogeneses of MS components and is involved in different mitochondrial signaling pathways that control respiration and apoptosis. The present review summarizes the recent information regarding the interrelations of mitochondria and NO in MS. Changes in the activities of different NO synthase isoforms lead to the formation of metabolic disorders and therefore are highlighted here. Reduced endothelial NOS activity and NO bioavailability, as the main factors underlying the endothelial dysfunction that occurs in MS, are discussed in this review in relation to mitochondrial dysfunction. We also focus on potential therapeutic strategies involving NO signaling pathways that can be used to treat patients with metabolic disorders associated with mitochondrial dysfunction. The article may help researchers develop new approaches for the diagnosis, prevention and treatment of MS. PMID:25741283

  11. ACTIVATION OF VASCULAR ENDOTHELIAL NITRIC OXIDE SYNTHASE AND HEME OXYGENASE-1 EXPRESSION BY ELECTROPHILIC NITRO-FATTY ACIDS

    PubMed Central

    Khoo, Nicholas K.H.; Rudolph, Volker; Cole, Marsha P.; Golin-Bisello, Franca; Schopfer, Francisco J.; Woodcock, Steven R.; Batthyany, Carlos; Freeman, Bruce A.

    2010-01-01

    Reactive oxygen species mediate a decrease in nitric oxide (NO) bioavailability and endothelial dysfunction, with secondary oxidized and nitrated byproducts of these reactions contributing to the pathogenesis of numerous vascular diseases. While oxidized lipids and lipoproteins exacerbate inflammatory reactions in the vasculature, in stark contrast the nitration of polyunsaturated fatty acids and complex lipids yield electrophilic products that exhibit pluripotent anti-inflammatory signaling capabilities acting via both cGMP-dependent and -independent mechanisms. Herein we report that nitro-oleic acid (OA-NO2) treatment increases expression of endothelial nitric oxide synthase (eNOS) and heme oxygenase 1 (HO-1) in the vasculature, thus transducing vascular protective effects associated with enhanced NO production. Administration of OA-NO2 via osmotic pump results in a significant increase in eNOS and HO-1 mRNA in mouse aortas. Moreover, HPLC-MS/MS analysis showed that NO2-FAs are rapidly metabolized in cultured endothelial cells (ECs) and treatment with NO2-FAs stimulated the phosphorylation of eNOS at Ser1179. These post-translational modifications of eNOS, in concert with elevated eNOS gene expression, contributed to an increase in endothelial NO production. In aggregate, OA-NO2-induced eNOS and HO-1 expression by vascular cells can induce beneficial effects on endothelial function and provide a new strategy for treating various vascular inflammatory and hypertensive disorders. PMID:19857569

  12. Involvement of nitric oxide through endocannabinoids release in microglia activation during the course of CNS regeneration in the medicinal leech.

    PubMed

    Arafah, Karim; Croix, Dominique; Vizioli, Jacopo; Desmons, Annie; Fournier, Isabelle; Salzet, Michel

    2013-04-01

    The medicinal leech is notable for its capacity to regenerate its central nervous system (CNS) following mechanical trauma. Using an electrochemical nitric oxide (NO)-selective electrode to measure NO levels, we found that the time course of NO release in the injured leech CNS is partially under the control of endocannabinoids, namely, N-arachidonyl ethanolamide (AEA) and 2-arachidonyl glycerol (2-AG). Relative quantification of these endocannabinoids was performed by stable isotope dilution (2AGd8 and AAEd8) coupled to mass spectrometry in course of regeneration process or adenosine triphosphate (ATP) treatment. Data show that 2-AG levels rose to a maximum about 30 min after injury or ATP treatment, and returned to baseline levels 4 h after injury. In same conditions, AEA levels also rapidly (within 5 min) dropped after injury or ATP treatment to the nerve cord, but did not fully return to baseline levels within 4 h of injury. In correlation with these data, chemoattraction activities of endocannabinoids on isolated leech microglial cells have been shown in vitro and in vivo reflecting that control over NO production is accompanied by the controlled chemoattraction of microglia directed from the periphery to the lesion site for neuronal repair purposes. Taken together, our results show that in the leech, after injury concurrent with ATP production, purinergic receptor activation, NO production, microglia recruitment, and accumulation to lesion site, a fine imbalance occurs in the endocannabinoid system. These events can bring explanations about the ability of the leech CNS to regenerate after a trauma and the key role of endocannabinoids in this phenomenon. PMID:23355252

  13. Paeonia japonica, Houttuynia cordata, and Aster scaber water extracts induce nitric oxide and cytokine production by lipopolysaccharide-activated macrophages.

    PubMed

    Kim, Jin; Park, Chang-Shin; Lim, Yunsook; Kim, Hyun-Sook

    2009-04-01

    Natural products are increasingly recognized as potential targets for drug discovery and development. We previously reported that Paeonia japonica, Houttuynia cordata, and Aster scaber enhanced macrophage activation both in vitro and in vivo. In the present study we investigated the immunomodulating effects of these plants on lipopolysacharide (LPS)-stimulated macrophages. An aqueous extract of each plant was administered to female BALB/c mice every other day for 4 weeks. Peritoneal macrophages were then collected and incubated to examine the immunoreactivity of macrophages against LPS at different time points. The expression levels of inducible nitric oxide (NO) synthetase (iNOS), cyclooxygenase (COX)-2, and inhibitory factor kappaB alpha (IkappaBalpha) proteins and the production of NO metabolite (nitrite), prostaglandin (PG) E(2), and the pro-inflammatory cytokines interleukin-1beta, interleukin-6, and tumor necrosis factor-alpha were determined in the activated macrophages treated with extracts from each plant individually or combined. High levels of pro-inflammatory cytokines were produced by A. scaber-, P. japonica-, and H. cordata-treated macrophages following 24 hours of LPS stimulation. P. japonica, H. cordata, and A. scaber treatment also induced the production of nitrate by LPS-treated macrophages. Induction of iNOS mRNA and protein was also different in each group. PGE(2) secretion was up-regulated by all extract-treated macrophages at early time points; however, no significant differences were observed between the groups by 8 hours post-LPS stimulation. Treatment with A. scaber extract resulted in the highest levels of IkappaBalpha degradation. Our findings illustrate that the natural plant products P. japonica, H. cordata, and A. scaber may enhance immune function by modulating ex vivo pro-inflammatory cytokine and NO production as well as the expression of iNOS and COX-2.

  14. Retinoic acid activates human inducible nitric oxide synthase gene through binding of RAR{alpha}/RXR{alpha} heterodimer to a novel retinoic acid response element in the promoter

    SciTech Connect

    Zou Fang; Liu Yan; Liu Li; Wu Kailang; Wei Wei; Zhu Ying . E-mail: yingzhu@whu.edu.cn; Wu Jianguo . E-mail: wu9988@vip.sina.com

    2007-04-06

    Human inducible nitric oxide synthase (hiNOS) catalyzes nitric oxide (NO) which has a significant effect on tumor suppression and cancer therapy. Here we revealed the detailed molecular mechanism involved in the regulation of hiNOS expression induced by retinoic acid (RA). We showed that RAR{alpha}/RXR{alpha} heterodimer was important in hiNOS promoter activation, hiNOS protein expression, and NO production. Serial deletion and site-directed mutation analysis revealed two half-sites of retinoic acid response element (RARE) spaced by 5 bp located at -172 to -156 in the hiNOS promoter. EMSA and ChIP assays demonstrated that RAR{alpha}/RXR{alpha} directly bound to this RARE of hiNOS promoter. Our results suggested the identification of a novel RARE in the hiNOS promoter and the roles of the nuclear receptors (RAR{alpha}/RXR{alpha}) in the induction of hiNOS by RA.

  15. Superoxide reactivates nitric oxide-inhibited catalase.

    PubMed

    Kim, Y S; Han, S

    2000-12-01

    Catalase binds nitric oxide (NO) to generate ferricatalase-NO, an inhibited form of the enzyme. Superoxide (O2-) is also an inactivator of the enzyme. We found, however, that O2- efficiently converted the inhibited ferricatalase-NO to the active ferricatalase without producing detectable intermediates. The reaction slowed down when O2- was disproportionated to H2O2 and O2 by superoxide dismutase, but H2O2 could displace the heme-bound NO slowly to regenerate ferricatalase. Reactivation was observed even under simultaneous generation of NO and O2-, suggesting that ferricatalase-NO reacts with O2- fast enough to compete with the rapid reaction of O2- and NO. Formation of peroxynitrite by the simultaneous generation of NO and O2- was only partially inhibited by ferricatalase, presumably due to slow binding of NO to catalase in comparison with the reaction of NO and O2-. PMID:11209763

  16. Nitric Oxide and Respiratory Helminthic Diseases

    PubMed Central

    Muro, Antonio; Pérez-Arellano, José-Luís

    2010-01-01

    Nitric oxide (NO) is a very simple molecule that displays very important functions both in helminths (mainly those involved in respiratory pathology) and in mammalian hosts. In this paper we review four issues related to interaction of NO and lung helminthic diseases. Firstly, we evaluated data available on the NO synthesis and release by helminths and their biological role. Next, we summarized the effect of antigens obtained from different phases of the biological cycle on NO production by host mammalian cells (mainly from human sources). Thirdly, we revised the evaluation of NO on the biological activities and/or the viability of respiratory helminths. Lastly, the deleterious consequences of increased production of NO during helminthic human infection are detailed. PMID:20169170

  17. Chemical constituents of malagasy Liverworts. 6. A myltaylane caffeate with nitric oxide inhibitory activity from Bazzania nitida.

    PubMed

    Harinantenaina, Liva; Asakawa, Yoshinori

    2007-05-01

    The phytochemical investigation of the Malagasy liverwort, Bazzania nitida, led to the isolation of (+)-(lS,4R)-7-hydroxycalamenene (1), together with a new myltayl-4(12)-ene-2-caffeate (2). Although cyclomyltaylane sesquiterpenoids have been known to be present in Bazzania species, this is the second isolation of myltaylane-type sesuiterpenoids from the genus. Biosynthetically, myltaylane sesquiterpenoids are proposed to be derived from chamigrene with a route different from those of cyclomyltaylanoids. The chemosystematics of Bazzania species is also discussed. Compound 2 showed potent inhibition of nitric oxide in LPS-induced RAW 264.7 cells (IC50 = 6.3 microM).

  18. Canine leishmaniasis in Southern Italy: a role for nitric oxide released from activated macrophages in asymptomatic infection?

    PubMed Central

    Panaro, Maria A; Brandonisio, Olga; de Caprariis, Donato; Cavallo, Pasqua; Cianciulli, Antonia; Mitolo, Vincenzo; Otranto, Domenico

    2008-01-01

    Background Human and canine leishmaniasis (CanL) by Leishmania infantum is endemic in Italy, with a high percentage of infected asymptomatic animals. However, the immune response mechanisms underlying the clinical presentation of CanL have not been fully investigated. Among leishmanicidal molecules produced by activated macrophages, nitric oxide (NO) produced by an inducible NO synthase seems to play an important protective role, but no conclusive data are available. Therefore, NO released by cultured macrophages from dogs with natural Leishmania infection living in an endemic area for CanL was evaluated. Methods On the basis of one year's clinical and laboratory follow-up, 22 dogs infected by Leishmania infantum were identified and grouped as: asymptomatic dogs (n = 13) and dogs with symptoms of leishmaniasis (n = 9). Each animal was bled twice at 4-month intervals and macrophage and lymphocyte cultures were obtained from peripheral blood mononuclear cells. Supernatants of L. infantum-infected macrophage cultures, with or without addition of autologous lymphocytes, were assayed for NO production by Griess reaction for nitrites. Results In the first months of the infection the levels of NO in supernatants of Leishmania-infected macrophages were higher in symptomatic than in asymptomatic dogs, but they were significantly increased in the latter group eight months after the diagnosis of infection. Furthermore, NO release significantly decreased in the presence of autologous lymphocytes in both groups of animals. Conclusion These results suggest that NO may be involved in the long-term protection of dogs against natural Leishmania infection and in the clinical presentation of canine leishmaniasis in the Mediterranean area. PMID:18471289

  19. Antimycobacterial and nitric oxide production inhibitory activities of Ocotea notata from Brazilian restinga.

    PubMed

    Costa, Isabela Francisca Borges; Calixto, Sanderson Dias; Heggdorne de Araujo, Marlon; Konno, Tatiana Ungaretti Paleo; Tinoco, Luzineide Wanderley; Guimarães, Denise Oliveira; Lasunskaia, Elena B; Leal, Ivana Ramos Correa; Muzitano, Michelle Frazão

    2015-01-01

    The genus Ocotea (Lauraceae) is distributed mainly in tropical and subtropical regions. Some species of this genus as O. puberula and O. quixos have been described in the literature, showing antibacterial activity. And Ocotea macrophylla showed anti-inflammatory activity with inhibition of COX-1, COX-2, and LOX-5. The purpose of this study was the phytochemical investigation of the plant species Ocotea notata from Restinga Jurubatiba National Park, Macaé, RJ, Brazil, and the search for antimycobacterial fractions and compounds. The crude extract was evaluated for antimycobacterial activity and presented 95.75 ± 2.53% of growth inhibition at 100 µg/mL. Then, it was subjected to a liquid-liquid partition and subsequently was chemically investigated by HPLC, revealing the major presence of flavonoids. In this process the partition fractions hexane, ethyl acetate, and butanol are shown to be promising in the antimycobacterial assay. In addition, ethyl acetate fraction was chromatographed and afforded two flavonoids identified by MS and NMR as afzelin and isoquercitrin. The isolated flavonoids afzelin and isoquercitrin were evaluated for their antimycobacterial activity and for their ability to inhibit NO production by macrophages stimulated by LPS; both flavonoids isoquercitrin (Acet22) and afzelin (Acet32) were able to inhibit the production of NO by macrophages. The calculated IC50 of Acet22 and Acet32 was 1.03 and 0.85 µg/mL, respectively.

  20. Antimycobacterial and Nitric Oxide Production Inhibitory Activities of Ocotea notata from Brazilian Restinga

    PubMed Central

    Costa, Isabela Francisca Borges; Calixto, Sanderson Dias; Heggdorne de Araujo, Marlon; Konno, Tatiana Ungaretti Paleo; Tinoco, Luzineide Wanderley; Guimarães, Denise Oliveira; Lasunskaia, Elena B.; Leal, Ivana Ramos Correa; Muzitano, Michelle Frazão

    2015-01-01

    The genus Ocotea (Lauraceae) is distributed mainly in tropical and subtropical regions. Some species of this genus as O. puberula and O. quixos have been described in the literature, showing antibacterial activity. And Ocotea macrophylla showed anti-inflammatory activity with inhibition of COX-1, COX-2, and LOX-5. The purpose of this study was the phytochemical investigation of the plant species Ocotea notata from Restinga Jurubatiba National Park, Macaé, RJ, Brazil, and the search for antimycobacterial fractions and compounds. The crude extract was evaluated for antimycobacterial activity and presented 95.75 ± 2.53% of growth inhibition at 100 µg/mL. Then, it was subjected to a liquid-liquid partition and subsequently was chemically investigated by HPLC, revealing the major presence of flavonoids. In this process the partition fractions hexane, ethyl acetate, and butanol are shown to be promising in the antimycobacterial assay. In addition, ethyl acetate fraction was chromatographed and afforded two flavonoids identified by MS and NMR as afzelin and isoquercitrin. The isolated flavonoids afzelin and isoquercitrin were evaluated for their antimycobacterial activity and for their ability to inhibit NO production by macrophages stimulated by LPS; both flavonoids isoquercitrin (Acet22) and afzelin (Acet32) were able to inhibit the production of NO by macrophages. The calculated IC50 of Acet22 and Acet32 was 1.03 and 0.85 µg/mL, respectively. PMID:25789338

  1. Arginase reciprocally regulates nitric oxide synthase activity and contributes to endothelial dysfunction in aging blood vessels

    NASA Technical Reports Server (NTRS)

    Berkowitz, Dan E.; White, Ron; Li, Dechun; Minhas, Khalid M.; Cernetich, Amy; Kim, Soonyul; Burke, Sean; Shoukas, Artin A.; Nyhan, Daniel; Champion, Hunter C.; Hare, Joshua M.

    2003-01-01

    BACKGROUND: Although abnormal L-arginine NO signaling contributes to endothelial dysfunction in the aging cardiovascular system, the biochemical mechanisms remain controversial. L-arginine, the NO synthase (NOS) precursor, is also a substrate for arginase. We tested the hypotheses that arginase reciprocally regulates NOS by modulating L-arginine bioavailability and that arginase is upregulated in aging vasculature, contributing to depressed endothelial function. METHODS AND RESULTS: Inhibition of arginase with (S)-(2-boronoethyl)-L-cysteine, HCl (BEC) produced vasodilation in aortic rings from young (Y) adult rats (maximum effect, 46.4+/-9.4% at 10(-5) mol/L, P<0.01). Similar vasorelaxation was elicited with the additional arginase inhibitors N-hydroxy-nor-L-arginine (nor-NOHA) and difluoromethylornithine (DFMO). This effect required intact endothelium and was prevented by 1H-oxadiazole quinoxalin-1-one (P<0.05 and P<0.001, respectively), a soluble guanylyl cyclase inhibitor. DFMO-elicited vasodilation was greater in old (O) compared with Y rat aortic rings (60+/-6% versus 39+/-6%, P<0.05). In addition, BEC restored depressed L-arginine (10(-4) mol/L)-dependent vasorelaxant responses in O rings to those of Y. Arginase activity and expression were increased in O rings, whereas NOS activity and cyclic GMP levels were decreased. BEC and DFMO suppressed arginase activity and restored NOS activity and cyclic GMP levels in O vessels to those of Y. CONCLUSIONS: These findings demonstrate that arginase modulates NOS activity, likely by regulating intracellular L-arginine availability. Arginase upregulation contributes to endothelial dysfunction of aging and may therefore be a therapeutic target.

  2. Nitric oxide/cGMP/PKG signaling pathway activated by M1-type muscarinic acetylcholine receptor cascade inhibits Na+-activated K+ currents in Kenyon cells.

    PubMed

    Hasebe, Masaharu; Yoshino, Masami

    2016-06-01

    The interneurons of the mushroom body, known as Kenyon cells, are essential for the long-term memory of olfactory associative learning in some insects. Some studies have reported that nitric oxide (NO) is strongly related to this long-term memory in Kenyon cells. However, the target molecules and upstream and downstream NO signaling cascades are not completely understood. Here we analyzed the effect of the NO signaling cascade on Na(+)-activated K(+) (KNa) channel activity in Kenyon cells of crickets (Gryllus bimaculatus). We found that two different NO donors, S-nitrosoglutathione (GSNO) and S-nitroso-N-acetyl-dl-penicillamine (SNAP), strongly suppressed KNa channel currents. Additionally, this inhibitory effect of GSNO on KNa channel activity was diminished by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase (sGC), and KT5823, an inhibitor of protein kinase G (PKG). Next, we analyzed the role of ACh in the NO signaling cascade. ACh strongly suppressed KNa channel currents, similar to NO donors. Furthermore, this inhibitory effect of ACh was blocked by pirenzepine, an M1 muscarinic ACh receptor antagonist, but not by 1,1-dimethyl-4-diphenylacetoxypiperidinium iodide (4-DAMP) and mecamylamine, an M3 muscarinic ACh receptor antagonist and a nicotinic ACh receptor antagonist, respectively. The ACh-induced inhibition of KNa channel currents was also diminished by the PLC inhibitor U73122 and the calmodulin antagonist W-7. Finally, we found that ACh inhibition was blocked by the nitric oxide synthase (NOS) inhibitor N(G)-nitro-l-arginine methyl ester (l-NAME). These results suggested that the ACh signaling cascade promotes NO production by activating NOS and NO inhibits KNa channel currents via the sGC/cGMP/PKG signaling cascade in Kenyon cells. PMID:26984419

  3. Thyroid disorders and nitric oxide in cardiovascular adaptation to hypovolemia.

    PubMed

    Ogonowski, Natalia; Piro, Giselle; Pessah, Déborah; Arreche, Noelia; Puchulu, Bernardita; Balaszczuk, Ana M; Fellet, Andrea L

    2016-08-01

    This study aimed to investigate whether nitric oxide participates in the cardiovascular function and haemodynamic adaptation to acute haemorrhage in animals with thyroid disorders. Sprague-Dawley rats aged 2months old treated with T3 (hyper, 20μg/100g body weight) or 0.02% methimazole (hypo, w/v) during 28days were pre-treated with N(G) nitro-l-arginine methyl ester (L-NAME) and submitted to 20% blood loss. Heart function was evaluated by echocardiography. Measurements of arterial blood pressure, heart rate, nitric oxide synthase activity and protein levels were performed. We found that hypo decreased fractional shortening and ejection fraction and increased left ventricle internal diameter. Hyper decreased ventricle diameter and no changes in cardiac contractility. Haemorrhage elicited a hypotension of similar magnitude within 10min. Then, this parameter was stabilized at about 30-40min and maintained until finalized, 120min. L-NAME rats showed that the immediate hypotension would be independent of nitric oxide. Nitric oxide synthase inhibition blunted the changes of heart rate induced by blood loss. Hyper and hypo had lower atrial enzyme activity associated with a decreased enzyme isoform in hypo. In ventricle, hyper and hypo had a higher enzyme activity, which was not correlated with changes in protein levels. Haemorrhage induced an increased heart nitric oxide production. We concluded that thyroid disorders were associated with hypertrophic remodelling which impacted differently on cardiac function and its adaptation to a hypovolemia. Hypovolemia triggered a nitric oxide synthase activation modulating the heart function to maintain haemodynamic homeostasis. This involvement depends on a specific enzyme isoform, cardiac chamber and thyroid state.

  4. Nitric oxide and receptors for VIP and PACAP in cutaneous active vasodilation during heat stress in humans.

    PubMed

    Kellogg, Dean L; Zhao, Joan L; Wu, Yubo; Johnson, John M

    2012-11-01

    VPAC2 receptors sensitive to vasoactive intestinal polypeptide (VIP) and pituitary adenylyl cyclase activating polypeptide (PACAP), PAC1 receptors sensitive to PACAP, and nitric oxide (NO) generation by NO synthase (NOS) are all implicated in cutaneous active vasodilation (AVD) through incompletely defined mechanisms. We hypothesized that VPAC2/PAC1 receptor activation and NO are synergistic and interdependent in AVD and tested our hypothesis by examining the effects of VPAC2/PAC1 receptor blockade with and without NOS inhibition during heat stress. The VPAC2/PAC1 antagonist, pituitary adenylate cyclase activating peptide 6-38 (PACAP6-38) and the NOS inhibitor, N(G)-nitro-l-arginine methyl ester (l-NAME) were administered by intradermal microdialysis. PACAP6-38, l-NAME, a combination of PACAP6-38 and l-NAME, or Ringer's solution alone were perfused at four separate sites. Skin blood flow was monitored by laser-Doppler flowmetry at each site. Body temperature was controlled with water-perfused suits. Blood pressure was monitored by Finapres, and cutaneous vascular conductance (CVC) calculated (CVC = laser-Doppler flowmetry/mean arterial pressure). The protocol began with a 5- to 10-min baseline period without antagonist perfusion, followed by perfusion of PACAP6-38, l-NAME, or combined PACAP6-38 and l-NAME at the different sites in normothermia (45 min), followed by 3 min of whole body cooling. Whole body heating was then performed to induce heat stress and activate AVD. Finally, 58 mM sodium nitroprusside were perfused at all sites to effect maximal vasodilation for normalization of blood flow data. No significant differences in CVC (normalized to maximum) were found among Ringer's PACAP6-38, l-NAME, or combined antagonist sites during normothermia (P > 0.05 among sites) or cold stress (P > 0.05 among sites). CVC responses at all treated sites were attenuated during AVD (P < 0.05 vs. Ringer's). Attenuation was greater at l-NAME and combined PACAP6-38- and l

  5. Potential of Inducible Nitric Oxide Synthase as a Therapeutic Target for Allergen-Induced Airway Hyperresponsiveness: A Critical Connection to Nitric Oxide Levels and PARP Activity

    PubMed Central

    Ghonim, Mohamed A.; Pyakurel, Kusma; Mishra, Anil

    2016-01-01

    Although expression of inducible NO synthase (iNOS) in the lungs of asthmatics and associated nitrosative damage are established, iNOS failed as a therapeutic target for blocking airway hyperresponsiveness (AHR) and inflammation in asthmatics. This dichotomy calls for better strategies with which the enzyme is adequately targeted. Here, we confirm iNOS expression in the asthmatic lung with concomitant protein nitration and poly(ADP-ribose) polymerase (PARP) activation. We show, for the first time, that iNOS is highly expressed in peripheral blood mononuclear cells (PBMCs) of asthmatics with uncontrolled disease, which did not correspond to protein nitration. Selective iNOS inhibition with L-NIL protected against AHR upon acute, but not chronic, exposure to ovalbumin or house dust mite (HDM) in mice. Supplementation of NO by nitrite administration significantly blocked AHR in chronically HDM-exposed mice that were treated with L-NIL. Protection against chronic HDM exposure-induced AHR by olaparib-mediated PARP inhibition may be associated with the partial but not the complete blockade of iNOS expression. Indeed, L-NIL administration prevented olaparib-mediated protection against AHR in chronically HDM-exposed mice. Our study suggests that the amount of iNOS and NO are critical determinants in the modulation of AHR by selective iNOS inhibitors and renews the potential of iNOS as a therapeutic target for asthma. PMID:27524861

  6. Potential of Inducible Nitric Oxide Synthase as a Therapeutic Target for Allergen-Induced Airway Hyperresponsiveness: A Critical Connection to Nitric Oxide Levels and PARP Activity.

    PubMed

    Ibba, Salome' V; Ghonim, Mohamed A; Pyakurel, Kusma; Lammi, Matthew R; Mishra, Anil; Boulares, A Hamid

    2016-01-01

    Although expression of inducible NO synthase (iNOS) in the lungs of asthmatics and associated nitrosative damage are established, iNOS failed as a therapeutic target for blocking airway hyperresponsiveness (AHR) and inflammation in asthmatics. This dichotomy calls for better strategies with which the enzyme is adequately targeted. Here, we confirm iNOS expression in the asthmatic lung with concomitant protein nitration and poly(ADP-ribose) polymerase (PARP) activation. We show, for the first time, that iNOS is highly expressed in peripheral blood mononuclear cells (PBMCs) of asthmatics with uncontrolled disease, which did not correspond to protein nitration. Selective iNOS inhibition with L-NIL protected against AHR upon acute, but not chronic, exposure to ovalbumin or house dust mite (HDM) in mice. Supplementation of NO by nitrite administration significantly blocked AHR in chronically HDM-exposed mice that were treated with L-NIL. Protection against chronic HDM exposure-induced AHR by olaparib-mediated PARP inhibition may be associated with the partial but not the complete blockade of iNOS expression. Indeed, L-NIL administration prevented olaparib-mediated protection against AHR in chronically HDM-exposed mice. Our study suggests that the amount of iNOS and NO are critical determinants in the modulation of AHR by selective iNOS inhibitors and renews the potential of iNOS as a therapeutic target for asthma. PMID:27524861

  7. Nitric Oxide Synthase and Breast Cancer: Role of TIMP-1 in NO-mediated Akt Activation

    PubMed Central

    Ridnour, Lisa A.; Barasch, Kimberly M.; Windhausen, Alisha N.; Dorsey, Tiffany H.; Lizardo, Michael M.; Yfantis, Harris G.; Lee, Dong H.; Switzer, Christopher H.; Cheng, Robert Y. S.; Heinecke, Julie L.; Brueggemann, Ernst; Hines, Harry B.; Khanna, Chand; Glynn, Sharon A.; Ambs, Stefan; Wink, David A.

    2012-01-01

    Prediction of therapeutic response and cancer patient survival can be improved by the identification of molecular markers including tumor Akt status. A direct correlation between NOS2 expression and elevated Akt phosphorylation status has been observed in breast tumors. Tissue inhibitor matrix metalloproteinase-1 (TIMP-1) has been proposed to exert oncogenic properties through CD63 cell surface receptor pathway initiation of pro-survival PI3k/Akt signaling. We employed immunohistochemistry to examine the influence of TIMP-1 on the functional relationship between NOS2 and phosphorylated Akt in breast tumors and found that NOS2-associated Akt phosphorylation was significantly increased in tumors expressing high TIMP-1, indicating that TIMP-1 may further enhance NO-induced Akt pathway activation. Moreover, TIMP-1 silencing by antisense technology blocked NO-induced PI3k/Akt/BAD phosphorylation in cultured MDA-MB-231 human breast cancer cells. TIMP-1 protein nitration and TIMP-1/CD63 co-immunoprecipitation was observed at NO concentrations that induced PI3k/Akt/BAD pro-survival signaling. In the survival analysis, elevated tumor TIMP-1 predicted poor patient survival. This association appears to be mainly restricted to tumors with high NOS2 protein. In contrast, TIMP-1 did not predict poor survival in patient tumors with low NOS2 expression. In summary, our findings suggest that tumors with high TIMP-1 and NOS2 behave more aggressively by mechanisms that favor Akt pathway activation. PMID:22957045

  8. Involvement of nitric oxide pathways in short term modulation of tyrosine hydroxylase activity by endothelins 1 and 3 in the rat anterior hypothalamus.

    PubMed

    Morgazo, Carolina; Perfume, Guadalupe; Legaz, Guillermina; di Nunzio, Andrea; Hope, Sandra I; Bianciotti, Liliana G; Vatta, Marcelo S

    2005-09-01

    The ability of endothelins 1 and 3 (ET-1 and ET-3) to reduce neuronal norepinephrine release through ETB receptor activation involving nitric oxide (NO) pathways in the rat anterior hypothalamus region (AHR) was previously reported. In the present work, we studied the effects of ET-1 and -3 on tyrosine hydroxylase (TH) activity and the possible involvement of NO pathways. Results showed that ET-1 and -3 (10 nM) diminished TH activity in AHR and this effect was blocked by a selective ETB receptor antagonist (100 nM BQ-788), but not by a ET(A) receptor antagonist (BQ-610). To confirm these results, 1 microM IRL-1620 (ET(B) agonist) reduced TH activity whereas 300 nM sarafotoxin S6b falled to modify it. N(omega)-Nitro-L-arginine methyl ester (10 microM), 7-nitroindazole (10 microM), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-ona (10 microM), KT5823 (2 microM), inhibitors of nitric oxide synthase, neuronal nitric oxide synthase, NO-sensitive-guanylyl cyclase, and protein kinase G, respectively, did not modify the reduction of TH activity produced by ETs. In addition, both 100 microM sodium nitroprusside and 50 microM 8-bromoguanosine-3',5'-cyclic monophosphate (NO donor and guanosine-3',5'-cyclic monophosphate analog, respectively) diminished TH activity. Present results showed that ET-1 and ET-3 diminished TH activity through the activation of ET(B) receptors involving the NO/guanosine-3',5'-cyclic monophosphate/protein kinase G pathway. Taken jointly present and previous results it can be concluded that both ETs play an important role as modulators of norepinephrine neurotransmission in the rat AHR.

  9. Ethylene mediates brassinosteroid-induced stomatal closure via Gα protein-activated hydrogen peroxide and nitric oxide production in Arabidopsis.

    PubMed

    Shi, Chenyu; Qi, Cheng; Ren, Hongyan; Huang, Aixia; Hei, Shumei; She, Xiaoping

    2015-04-01

    Brassinosteroids (BRs) are essential for plant growth and development; however, whether and how they promote stomatal closure is not fully clear. In this study, we report that 24-epibrassinolide (EBR), a bioactive BR, induces stomatal closure in Arabidopsis (Arabidopsis thaliana) by triggering a signal transduction pathway including ethylene synthesis, the activation of Gα protein, and hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) production. EBR initiated a marked rise in ethylene, H(2)O(2) and NO levels, necessary for stomatal closure in the wild type. These effects were abolished in mutant bri1-301, and EBR failed to close the stomata of gpa1 mutants. Next, we found that both ethylene and Gα mediate the inductive effects of EBR on H(2)O(2) and NO production. EBR-triggered H(2)O(2) and NO accumulation were canceled in the etr1 and gpa1 mutants, but were strengthened in the eto1-1 mutant and the cGα line (constitutively overexpressing the G protein α-subunit AtGPA1). Exogenously applied H(2)O(2) or sodium nitroprusside (SNP) rescued the defects of etr1-3 and gpa1 or etr1 and gpa1 mutants in EBR-induced stomatal closure, whereas the stomata of eto1-1/AtrbohF and cGα/AtrbohF or eto1-1/nia1-2 and cGα/nia1-2 constructs had an analogous response to H(2)O(2) or SNP as those of AtrbohF or Nia1-2 mutants. Moreover, we provided evidence that Gα plays an important role in the responses of guard cells to ethylene. Gα activator CTX largely restored the lesion of the etr1-3 mutant, but ethylene precursor ACC failed to rescue the defects of gpa1 mutants in EBR-induced stomatal closure. Lastly, we demonstrated that Gα-activated H(2)O(2) production is required for NO synthesis. EBR failed to induce NO synthesis in mutant AtrbohF, but it led to H(2)O(2) production in mutant Nia1-2. Exogenously applied SNP rescued the defect of AtrbohF in EBR-induced stomatal closure, but H(2)O(2) did not reverse the lesion of EBR-induced stomatal closure in Nia1-2. Together, our

  10. Induction of nitric oxide synthase activity by toxic shock syndrome toxin 1 in a macrophage-monocyte cell line.

    PubMed Central

    Zembowicz, A; Vane, J R

    1992-01-01

    Toxic shock syndrome toxin 1 (TSST-1) is a Mr 22,000 protein produced by Staphylococcus aureus. It is thought to be the cause of toxic shock syndrome. We investigated the hypothesis that TSST-1 induces nitric oxide (NO) synthase and that the NO formed may be involved in the pathogenesis of toxic shock syndrome. We used the murine monocyte-macrophage cell line J744.2 that responds to TSST-1 and also expresses NO synthase activity upon immunological stimulation. J774.2 macrophages stimulated with TSST-1 (10-100 nM) generated nitrite, a breakdown product of NO, and induced concentration-dependent elevations of cGMP in the pig kidney epithelial cell line (LLC-PK1). This latter effect was due to the generation of L-arginine-derived NO for it was (i) abolished by oxyhemoglobin (10 microM), a scavenger of NO, or by methylene blue (10 microM), an inhibitor of NO-activated guanylate cyclase; (ii) potentiated by superoxide dismutase (100 units/ml), which prolongs the life of NO; (iii) inhibited by NG-monomethyl-L-arginine (0.3 mM), an inhibitor of NO synthase; (iv) significantly decreased when L-arginine (0.4 mM) in the medium was replaced by D-arginine (0.4 mM). Moreover, TSST-1 (100 nM) enhanced the activity of cytosolic NO synthase in J774.2 cells. Hydrocortisone (1 microM) but not indomethacin (5 micrograms/ml) or salicylic acid (5 micrograms/ml) prevented the generation of NO2- and the increases in cGMP levels in LLC-PK1 cells induced by J774.2 cells stimulated with TSST-1. The effects of hydrocortisone were partially reversed by coincubation with RU 486 (1 microM), an antagonist of glucocorticoid receptors. Thus, TSST-1 and perhaps other exotoxins produced by Gram-positive bacteria induce NO synthase and the increased NO formation may contribute to toxic shock syndrome and possibly to changes in the immune responses that accompany infection. PMID:1372433

  11. BIOGENIC NITRIC OXIDE EMISSIONS FROM CROPLAND SOILS

    EPA Science Inventory

    Emissions of nitric oxide (NO) were determined during late spring and summer 1995 and the spring of 1996 from four agricultural soils on which four different crops were grown. These agricultural soils were located at four different sites throughout North Carolina. Emission rates ...

  12. Inhibitory effects of sesquiterpenes from bay leaf on nitric oxide production in lipopolysaccharide-activated macrophages: structure requirement and role of heat shock protein induction.

    PubMed

    Matsuda, H; Kagerura, T; Toguchida, I; Ueda, H; Morikawa, T; Yoshikawa, M

    2000-04-21

    The methanolic extract from the leaves of Laurus nobilis (bay leaf, laurel) was found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-activated mouse peritoneal macrophages. Through bioassay-guided separation, fourteen known sesquiterpenes were isolated from the active fraction and were examined for ability to inhibit the NO production. Seven sesquiterpene lactones (costunolide, dehydrocostus lactone, eremanthine, zaluzanin C, magnolialide, santamarine and spirafolide) potently inhibited LPS-induced NO production (IC50 = 1.2 approximately 3.8 microM). Other sesquiterpene constituents also showed the inhibitory activity (IC50 > or = 21 microM), but their inhibitory activities were less than those of sesquiterpene lactones. Alpha-methylene-gamma-butyrolactone also showed inhibitory activity (IC50 = 9.6 microM), while mokko lactone and watsonol A etc., reductants of the alpha-methylene-gamma-butyrolactone moiety by NaBH4 or DIBAL, and a 2-mercaptoethanol adduct of dehydrocostus lactone showed little activity (IC50 > or = 18 microM). These results indicated that the alpha-methylene-gamma-butyrolactone moiety is important for the activity. Furthermore, costunolide and dehydrocostus lactone inhibited inducible nitric oxide synthase (iNOS) induction in accordance with induction of heat shock protein 72 (HSP 72). These results suggested that, as one of their mechanisms of action, sesquiterpene lactones induce HSP 72 thereby preventing nuclear factor-kappaB activation followed by iNOS induction.

  13. Sepiapterin attenuates 1-methyl-4-phenylpyridinium-induced apoptosis in neuroblastoma cells transfected with neuronal NOS: role of tetrahydrobiopterin, nitric oxide, and proteasome activation.

    PubMed

    Shang, Tiesong; Kotamraju, Srigiridhar; Zhao, Hongtao; Kalivendi, Shasi V; Hillard, Cecilia J; Kalyanaraman, B

    2005-10-15

    In this study, we investigated the molecular mechanism of toxicity of 1-methyl-4-phenylpyridinium (MPP+), an ultimate toxic metabolite of a mitochondrial neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, that causes parkinsonism in experimental animals and humans. Using wild-type and human neuronal nitric oxide synthase (nNOS) stably transfected neuroblastoma cells (SH-SY5Y), we showed that nNOS overexpression in SH-SY5Y cells greatly enhanced proteasome activity and mitigated MPP+-induced apoptosis. During MPP+-induced oxidative stress, intracellular BH4 levels decreased, resulting in nNOS "uncoupling" (i.e., switching from nitric oxide to superoxide generation). Increasing the intracellular BH4 levels by sepiapterin supplementation restored the nNOS activity, inhibited superoxide formation, increased proteasome activity, decreased protein ubiquitination, and attenuated apoptosis in MPP+-treated cells. Implications of BH4 depletion in dopaminergic cells and sepiapterin supplementation to augment the striatal nNOS activity in the pathogenesis mechanism and treatment of Parkinson disease are discussed. PMID:16198233

  14. Apple fruit responses following exposure to nitric oxide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exogenous nitric oxide (.NO) applied as gas or generated from .NO releasing compounds has physiological activity in cut apple fruit tissues. Studies were conducted to characterize .NO production by whole fruit as well as to assess responses of whole fruit to exogenous .NO. .NO and ethylene product...

  15. Internally applied endotoxin and the activation of BK channels in cerebral artery smooth muscle via a nitric oxide-like pathway.

    PubMed

    Hoang, L M; Mathers, D A

    1998-01-01

    1. In this study the role of nitric oxide synthase (NOS) in the acute activation of large conductance, Ca2+-activated K+ channels (BK channels) by internally applied E. coli lipopolysaccharide (LPS, endotoxin) was examined in vascular smooth muscle cells. 2. Cerebrovascular smooth muscle cells (CVSMCs) were enzymatically dispersed from the middle, posterior communicating and posterior cerebral arteries of adult Wistar rats and maintained at 4 degrees C for 2-4 days before recording with standard patch-clamp techniques. 3. Acute application of LPS (100 microg ml(-1)) to inside-out patches of CVSMC membrane isolated in a cell-free environment rapidly and reversibly increased the open probability, Po of BK channels in these patches by 3.3+/-0.30 fold. 4. Acute application of the nitric oxide (NO) donor sodium nitroprusside (SNP, 100 microM) to inside-out patches of CVSMC membrane, studied in the presence of intact cells, also reversibly increased Po, by some 1.8+/-0.2 fold over control. 5. Kinetic analysis showed that both LPS and SNP increased Po by accelerating the rate of BK channel reopening, rather than by retarding the closure of open channels. 6. Neither LPS nor SNP altered the reversal potential or conductance of BK channels. 7. The NOS substrate L-arginine (1 microM) potentiated the acute activation of BK channels by LPS, while the synthetic enantiomer D-arginine (1 microM) inhibited the action of LPS on BK channels. 8. The acute activation of BK channels by LPS was suppressed by pre-incubation of cells with N(omega)-nitro-L-arginine (50 microM) or N(omega)-nitro-L-arginine methyl ester (1 mM), two competitive antagonists of nitric oxide synthases. N(omega)-nitro-D-arginine (50 microM), a poor inhibitor of NOS in in vitro assays, had no effect on BK channel activation by LPS. 9. These results indicate that excised, inside-out patches of CVSMC membrane exhibit a NOS-like activity which is acutely activated when LPS is present at the cytoplasmic membrane

  16. Internally applied endotoxin and the activation of BK channels in cerebral artery smooth muscle via a nitric oxide-like pathway

    PubMed Central

    Hoang, L M; Mathers, D A

    1998-01-01

    In this study the role of nitric oxide synthase (NOS) in the acute activation of large conductance, Ca2+-activated K+ channels (BK channels) by internally applied E. coli lipopolysaccharide (LPS, endotoxin) was examined in vascular smooth muscle cells.Cerebrovascular smooth muscle cells (CVSMCs) were enzymatically dispersed from the middle, posterior communicating and posterior cerebral arteries of adult Wistar rats and maintained at 4°C for 2–4 days before recording with standard patch-clamp techniques.Acute application of LPS (100 μg ml−1) to inside-out patches of CVSMC membrane isolated in a cell-free environment rapidly and reversibly increased the open probability, Po of BK channels in these patches by 3.3±0.30 fold.Acute application of the nitric oxide (NO) donor sodium nitroprusside (SNP, 100 μM) to inside-out patches of CVSMC membrane, studied in the presence of intact cells, also reversibly increased Po, by some 1.8±0.2 fold over control.Kinetic analysis showed that both LPS and SNP increased Po by accelerating the rate of BK channel reopening, rather than by retarding the closure of open channels.Neither LPS nor SNP altered the reversal potential or conductance of BK channels.The NOS substrate L-arginine (1 μM) potentiated the acute activation of BK channels by LPS, while the synthetic enantiomer D-arginine (1 μM) inhibited the action of LPS on BK channels.The acute activation of BK channels by LPS was suppressed by pre-incubation of cells with Nω-nitro-L-arginine (50 μM) or Nω-nitro-L-arginine methyl ester (1  mM), two competitive antagonists of nitric oxide synthases. Nω-nitro-D-arginine (50 μM), a poor inhibitor of NOS in in vitro assays, had no effect on BK channel activation by LPS.These results indicate that excised, inside-out patches of CVSMC membrane exhibit a NOS-like activity which is acutely activated when LPS is present at the cytoplasmic membrane surface. Possible relationships between this novel mechanism

  17. Nitric Oxide Suppresses β-Cell Apoptosis by Inhibiting the DNA Damage Response.

    PubMed

    Oleson, Bryndon J; Broniowska, Katarzyna A; Naatz, Aaron; Hogg, Neil; Tarakanova, Vera L; Corbett, John A

    2016-08-01

    Nitric oxide, produced in pancreatic β cells in response to proinflammatory cytokines, plays a dual role in the regulation of β-cell fate. While nitric oxide induces cellular damage and impairs β-cell function, it also promotes β-cell survival through activation of protective pathways that promote β-cell recovery. In this study, we identify a novel mechanism in which nitric oxide prevents β-cell apoptosis by attenuating the DNA damage response (DDR). Nitric oxide suppresses activation of the DDR (as measured by γH2AX formation and the phosphorylation of KAP1 and p53) in response to multiple genotoxic agents, including camptothecin, H2O2, and nitric oxide itself, despite the presence of DNA damage. While camptothecin and H2O2 both induce DDR activation, nitric oxide suppresses only camptothecin-induced apoptosis and not H2O2-induced necrosis. The ability of nitric oxide to suppress the DDR appears to be selective for pancreatic β cells, as nitric oxide fails to inhibit DDR signaling in macrophages, hepatocytes, and fibroblasts, three additional cell types examined. While originally described as the damaging agent responsible for cytokine-induced β-cell death, these studies identify a novel role for nitric oxide as a protective molecule that promotes β-cell survival by suppressing DDR signaling and attenuating DNA damage-induced apoptosis. PMID:27185882

  18. Nitric Oxide Synthases in Heart Failure

    PubMed Central

    Carnicer, Ricardo; Crabtree, Mark J.; Sivakumaran, Vidhya

    2013-01-01

    Abstract Significance: The regulation of myocardial function by constitutive nitric oxide synthases (NOS) is important for the maintenance of myocardial Ca2+ homeostasis, relaxation and distensibility, and protection from arrhythmia and abnormal stress stimuli. However, sustained insults such as diabetes, hypertension, hemodynamic overload, and atrial fibrillation lead to dysfunctional NOS activity with superoxide produced instead of NO and worse pathophysiology. Recent Advances: Major strides in understanding the role of normal and abnormal constitutive NOS in the heart have revealed molecular targets by which NO modulates myocyte function and morphology, the role and nature of post-translational modifications of NOS, and factors controlling nitroso-redox balance. Localized and differential signaling from NOS1 (neuronal) versus NOS3 (endothelial) isoforms are being identified, as are methods to restore NOS function in heart disease. Critical Issues: Abnormal NOS signaling plays a key role in many cardiac disorders, while targeted modulation may potentially reverse this pathogenic source of oxidative stress. Future Directions: Improvements in the clinical translation of potent modulators of NOS function/dysfunction may ultimately provide a powerful new treatment for many hearts diseases that are fueled by nitroso-redox imbalance. Antioxid. Redox Signal. 18, 1078–1099. PMID:22871241

  19. Oxidized LDL at low concentration promotes in-vitro angiogenesis and activates nitric oxide synthase through PI3K/Akt/eNOS pathway in human coronary artery endothelial cells

    SciTech Connect

    Yu, Shan; Wong, Siu Ling; Lau, Chi Wai; Huang, Yu; Yu, Cheuk-Man

    2011-04-01

    Research highlights: {yields} Low-concentration oxidized LDL enhances angiogenesis through nitric oxide (NO). {yields} Oxidized LDL increases intracellular NO levels via eNOS phosphorylation. {yields} Akt/PI3K signaling mediates oxidized LDL-induced eNOS phosphorylation. -- Abstract: It has long been considered that oxidized low-density lipoprotein (oxLDL) causes endothelial dysfunction and is remarkably related to the development of atherosclerosis. However, the effect of oxLDL at very low concentration (<10 {mu}g/ml) on the endothelial cells remains speculative. Nitric oxide (NO) has a crucial role in the endothelial cell function. In this study, we investigated the effect of oxLDL at low concentration on NO production and proliferation, migration, tube formation of the human coronary artery endothelial cells (HCAEC). Results showed that oxLDL at 5 {mu}g/ml enhanced HCAEC proliferation, migration and tube formation. These phenomena were accompanied by an increased intracellular NO production. L-NAME (a NOS inhibitor), LY294002 and wortmannin (PI3K inhibitors) could abolish oxLDL-induced angiogenic effects and prevent NO production in the HCAEC. The phosphorylation of Akt, PI3K and eNOS were up-regulated by oxLDL, which was attenuated by LY294002. Our results suggested that oxLDL at low concentration could promote in-vitro angiogenesis and activate nitric oxide synthesis through PI3K/Akt/eNOS pathway in HCAEC.

  20. Nitric oxide synthase and nitric oxide alterations in chronically stressed rats: a model for nitric oxide in major depressive disorder.

    PubMed

    Gao, Shang-Feng; Lu, Yun-Rong; Shi, Li-Gen; Wu, Xue-Yan; Sun, Bo; Fu, Xin-Yan; Luo, Jian-Hong; Bao, Ai-Min

    2014-09-01

    Nitric oxide (NO) and NO synthase-1 (NOS1) are involved in the stress response and in depression. We compared NOS-NO alterations in rats exposed to chronic unpredictable stress (CUS) with alterations in major depressive disorder (MDD) in humans. In the hypothalamus of male CUS rats we determined NOS activity, and in the paraventricular nucleus (PVN) we determined NOS1-immunoreactive (ir) cell densities and co-localization of NOS1 with stress-related neuropeptides corticotropin-releasing hormone (CRH), vasopressin (AVP) or oxytocin (OXT). We measured plasma NO levels and cortisol in male medicine-naïve MDD patients and plasma NO and corticosterone (CORT) in CUS rats. In the CUS rat total NOS activity in the hypothalamus (P=0.018) and NOS1-ir cell density in the PVN were both significantly decreased (P=0.018), while NOS1 staining was mainly expressed in OXT-ir neurons in this nucleus. Interestingly, plasma NO levels were significantly increased both in male CUS rats (P=0.001) and in male MDD patients (P<0.001). Plasma CORT levels were increased in male CUS rats (P=0.001), while male MDD patients did not show a significant change in cortisol levels. In conclusion, the changes in plasma and hypothalamic NOS-NO of CUS rats and MDD were similar. The male CUS rat model may thus help us with our investigation of the mechanism underlying NOS-NO alterations in depression.

  1. Nitric oxide is involved in heat-induced HSP70 accumulation.

    PubMed

    Malyshev IYu; Manukhina, E B; Mikoyan, V D; Kubrina, L N; Vanin, A F

    1995-08-21

    Heat shock potentiated the nitric oxide production (EPR assay) in the liver, kidney, heart, spleen, intestine, and brain. The heat shock-induced sharp transient increase in the rate of nitric oxide production preceded the accumulation of heat shock proteins (HSP70) (Western blot analysis) as measured in the heart and liver. In all organs the nitric oxide formation was completely blocked by the NO-synthase inhibitor N omega-nitro-L-arginine (L-NNA). L-NNA also markedly attenuated the heat shock-induced accumulation of HSP70. The results suggests that nitric oxide is involved in the heat shock-induced activation of HSP70 synthesis. PMID:7544743

  2. The involvement of nitric oxide in the hemodynamic and metabolic activities of the brain and small intestine

    NASA Astrophysics Data System (ADS)

    Tolmasov, M.; Barbiro-Michaely, E.; Mayevsky, A.

    2009-02-01

    Nitric oxide is a mediator in many physiological processes including vasodilatation of blood vessels, neurotransmission and prevention of platelet aggregation. It has also a role in the pathophysiology of sepsis, hemorrhagic shock, various traumatic events and critical conditions involved with circulatory abnormalities. The last one is accompanied by blood flow redistribution and is considered to be the putative cause of altered oxygen metabolism in various pathophysiological conditions. The present study tested the involvement of NO in the brain as a vital organ versus the small intestine, a less vital organ using the non-specific nitric oxide synthase inhibitor L-NAME and exogenous NO donor - nitrite. The parameters that were simultaneously monitored in both organs included mean arterial blood pressure (MAP), tissue blood flow (TBF), using laser Doppler flowmetery and NADH fluorescence using the fluorometric technique. Three groups were tested. Group 1 - L-NAME +nitrite, group 2 - control L-NAME and group 3 - control nitrite. Following LNAME, MAP significantly increased and remained elevated through the entire experiment. TBF decreased in both organs with full recovery in the brain and no recovery in the intestine, whereas NADH showed no significant changes. Nitrite alone had no significant effect on the parameters in any of the organs. In group 1 the infusion of nitrite decreased the level of elevated MAP earlier induced by L-NAME. Nitrite also recovered the reduced TBF in the brain whereas it had no beneficial effect on intestinal blood flow indicating for its regulatory role in the brain but not in the intestine.

  3. Nitric oxide releasing material adsorbs more fibrinogen.

    PubMed

    Lantvit, Sarah M; Barrett, Brittany J; Reynolds, Melissa M

    2013-11-01

    One mechanism of the failure of blood-contacting devices is clotting. Nitric oxide (NO) releasing materials are seen as a viable solution to the mediation of surface clotting by preventing platelet activation; however, NO's involvement in preventing clot formation extends beyond controlling platelet function. In this study, we evaluate NO's effect on factor XII (fibrinogen) adsorption and activation, which causes the initiation of the intrinsic arm of the coagulation cascade. This is done by utilizing a model plasticized poly(vinyl) chloride (PVC), N-diazeniumdiolate system and looking at the adsorption of fibrinogen, an important clotting protein, to these surfaces. The materials have been prepared in such a way to eliminate changes in surface properties between the control (plasticized PVC) and composite (NO-releasing) materials. This allows us to isolate NO release and determine the effect on the adsorption of fibrinogen, to the material surface. Surprisingly, it was found that an NO releasing material with a surface flux of 17.4 ± 0.5 × 10(-10) mol NO cm(-2) min(-1) showed a significant increase in the amount of fibrinogen adsorbed to the material surface compared to one with a flux of 13.0 ± 1.6 × 10(-10) mol NO cm(-2) min(-1) and the control (2334 ± 496, 226 ± 99, and 103 ±31% fibrinogen adsorbed of control, respectively). This study suggests that NO's role in controlling clotting is extended beyond platelet activation. PMID:23554300

  4. Activation of nuclear factor erythroid 2-related factor 2 coordinates dimethylarginine dimethylaminohydrolase/PPAR-γ/endothelial nitric oxide synthase pathways that enhance nitric oxide generation in human glomerular endothelial cells.

    PubMed

    Luo, Zaiming; Aslam, Shakil; Welch, William J; Wilcox, Christopher S

    2015-04-01

    Dimethylarginine dimethylaminohydrolase (DDAH) degrades asymmetric dimethylarginine, which inhibits nitric oxide (NO) synthase (NOS). Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcriptional factor that binds to antioxidant response elements and transcribes many antioxidant genes. Because the promoters of the human DDAH-1 and DDAH-2, endothelial NOS (eNOS) and PPAR-γ genes contain 2 to 3 putative antioxidant response elements, we hypothesized that they were regulated by Nrf2/antioxidant response element. Incubation of human renal glomerular endothelial cells with the Nrf2 activator tert-butylhydroquinone (20 μmol·L(-1)) significantly (P<0.05) increased NO and activities of NOS and DDAH and decreased asymmetric dimethylarginine. It upregulated genes for hemoxygenase-1, eNOS, DDAH-1, DDAH-2, and PPAR-γ and partitioned Nrf2 into the nucleus. Knockdown of Nrf2 abolished these effects. Nrf2 bound to one antioxidant response element on DDAH-1 and DDAH-2 and PPAR-γ promoters but not to the eNOS promoter. An increased eNOS and phosphorylated eNOS (P-eNOSser-1177) expression with tert-butylhydroquinone was prevented by knockdown of PPAR-γ. Expression of Nrf2 was reduced by knockdown of PPAR-γ, whereas PPAR-γ was reduced by knockdown of Nrf2, thereby demonstrating 2-way positive interactions. Thus, Nrf2 transcribes HO-1 and other genes to reduce reactive oxygen species, and DDAH-1 and DDAH-2 to reduce asymmetric dimethylarginine and PPAR-γ to increase eNOS and its phosphorylation and activity thereby coordinating 3 pathways that enhance endothelial NO generation. PMID:25691623

  5. Nitric oxide stress and activation of AMP-activated protein kinase impair β-cell sarcoendoplasmic reticulum calcium ATPase 2b activity and protein stability

    PubMed Central

    Tong, X; Kono, T; Evans-Molina, C

    2015-01-01

    The sarcoendoplasmic reticulum Ca2+ ATPase 2b (SERCA2b) pump maintains a steep Ca2+ concentration gradient between the cytosol and ER lumen in the pancreatic β-cell, and the integrity of this gradient has a central role in regulated insulin production and secretion, maintenance of ER function and β-cell survival. We have previously demonstrated loss of β-cell SERCA2b expression under diabetic conditions. To define the mechanisms underlying this, INS-1 cells and rat islets were treated with the proinflammatory cytokine interleukin-1β (IL-1β) combined with or without cycloheximide or actinomycin D. IL-1β treatment led to increased inducible nitric oxide synthase (iNOS) gene and protein expression, which occurred concurrently with the activation of AMP-activated protein kinase (AMPK). IL-1β led to decreased SERCA2b mRNA and protein expression, whereas time-course experiments revealed a reduction in protein half-life with no change in mRNA stability. Moreover, SERCA2b protein but not mRNA levels were rescued by treatment with the NOS inhibitor l-NMMA (NG-monomethyl l-arginine), whereas the NO donor SNAP (S-nitroso-N-acetyl-d,l-penicillamine) and the AMPK activator AICAR (5-aminoimidazole-4-carboxamide ribonucleotide) recapitulated the effects of IL-1β on SERCA2b protein stability. Similarly, IL-1β-induced reductions in SERCA2b expression were rescued by pharmacological inhibition of AMPK with compound C or by transduction of a dominant-negative form of AMPK, whereas β-cell death was prevented in parallel. Finally, to determine a functional relationship between NO and AMPK signaling and SERCA2b activity, fura-2/AM (fura-2-acetoxymethylester) Ca2+ imaging experiments were performed in INS-1 cells. Consistent with observed changes in SERCA2b expression, IL-1β, SNAP and AICAR increased cytosolic Ca2+ and decreased ER Ca2+ levels, suggesting congruent modulation of SERCA activity under these conditions. In aggregate, these results show that SERCA2b protein

  6. Nitric oxide methods in seed biology.

    PubMed

    Bethke, Paul C; Libourel, Igor G L; Vitecek, Jan; Jones, Russell L

    2011-01-01

    The ubiquitous signaling molecule nitric oxide (NO) plays an important role in seed biology. Experiments with this biologically important gas require special provisions because NO in aerobic environments is readily converted into other oxides of nitrogen. In this chapter, we describe methods for the application of NO as a gas, and through the use of NO-donor compounds. We included information on the removal or reduction of NO with NO scavengers. Methods for detecting NO using NO-reactive fluorescent probes, and an apparatus incorporating an oxidizer column are also described.

  7. Nitric oxide production and nitric oxide synthase immunoreactivity in Naegleria fowleri.

    PubMed

    Rojas-Hernández, Saúl; Rodríguez-Monroy, Marco A; Moreno-Fierros, Leticia; Jarillo-Luna, Adriana; Carrasco-Yepez, Marisela; Miliar-García, Angel; Campos-Rodríguez, Rafael

    2007-07-01

    Free-living ameba Naegleria fowleri produces an acute and fatal infectious disease called primary amebic meningoencephalitis (PAM), whose pathophysiological mechanism is largely unknown. The aim of this study was to investigate the role of nitric oxide (NO) in PAM. Although NO has a cytotoxic effect on various parasites, it is produced by others as part of the pathology, as is the case with Entamoeba histolytica. To test for the production of NO, we analyzed whether antibodies against mammalian NO synthase isoforms (neuronal, inducible, and endothelial) presented immunoreactivity to N. fowleri proteins. We found that the trophozoites produced NO in vitro. The Western blot results, which showed N. fowleri trophozoites, contained proteins that share epitopes with the three described mammalian NOS, but have relative molecular weights different than those described in the literature, suggesting that N. fowleri may contain undescribed NOS isoforms. Moreover, we found that trophozoites reacted to the NOS2 antibody, in amebic cultures as well as in the mouse brain infected with N. fowleri, suggesting that nitric oxide may participate in the pathogenesis of PAM. Further research aimed at determining whether N. fowleri contains active novel NOS isoforms could lead to the design of new therapies against this parasite.

  8. Hypotension and reduced nitric oxide-elicited vasorelaxation in transgenic mice overexpressing endothelial nitric oxide synthase.

    PubMed Central

    Ohashi, Y; Kawashima, S; Hirata, K i; Yamashita, T; Ishida, T; Inoue, N; Sakoda, T; Kurihara, H; Yazaki, Y; Yokoyama, M

    1998-01-01

    Nitric oxide (NO), constitutively produced by endothelial nitric oxide synthase (eNOS), plays a major role in the regulation of blood pressure and vascular tone. We generated transgenic mice overexpressing bovine eNOS in the vascular wall using murine preproendothelin-1 promoter. In transgenic lineages with three to eight transgene copies, bovine eNOS-specific mRNA, protein expression in the particulate fractions, and calcium-dependent NOS activity were confirmed by RNase protection assay, immunoblotting, and L-arginine/citrulline conversion. Immunohistochemical studies revealed that eNOS protein was predominantly localized in the endothelial cells of aorta, heart, and lung. Blood pressure was significantly lower in eNOS-overexpressing mice than in control littermates. In the transgenic aorta, basal NO release (estimated by Nomega-nitro-L-arginine-induced facilitation of the contraction by prostaglandin F2alpha) and basal cGMP levels (measured by enzyme immunoassay) were significantly increased. In contrast, relaxations of transgenic aorta in response to acetylcholine and sodium nitroprusside were significantly attenuated, and the reduced vascular reactivity was associated with reduced response of cGMP elevation to these agents as compared with control aortas. Thus, our novel mouse model of chronic eNOS overexpression demonstrates that, in addition to the essential role of eNOS in blood pressure regulation, tonic NO release by eNOS in the endothelium induces the reduced vascular reactivity to NO-mediated vasodilators, providing several insights into the pathogenesis of nitrate tolerance. PMID:9854041

  9. Involvement of major components from Sporothrix schenckii cell wall in the caspase-1 activation, nitric oxide and cytokines production during experimental sporotrichosis.

    PubMed

    Gonçalves, Amanda Costa; Maia, Danielle Cardoso Geraldo; Ferreira, Lucas Souza; Monnazzi, Luis Gustavo Silva; Alegranci, Pâmela; Placeres, Marisa Campos Polesi; Batista-Duharte, Alexander; Carlos, Iracilda Zeppone

    2015-02-01

    Sporotrichosis is a chronic infection caused by the dimorphic fungus Sporothrix schenckii, involving all layers of skin and the subcutaneous tissue. The role of innate immune toll-like receptors 2 and 4 in the defense against this fungus has been reported, but so far, there were no studies on the effect of cell wall major components over the cytosolic oligo-merization domain (NOD)-like receptors, important regulators of inflammation and responsible for the maturation of IL-1β and IL-18, whose functions are dependents of the caspase-1 activation, that can participate of inflammasome. It was evaluated the percentage of activation of caspase-1, the production of IL-1β, IL-18, IL-17, IFN-γ and nitric oxide in a Balb/c model of S. schenckii infection. It was observed a decreased activity of caspase-1 during the fourth and sixth weeks of infection accompanied by reduced secretion of the cytokines IL-1β, IL-18 and IL-17 and high production of nitric oxide. IFN-γ levels were elevated during the entire time course of infection. This temporal reduction in caspase-1 activity coincides exactly with the reported period of fungal burden associated with a transitory immunosuppression induced by this fungus and detected in similar infection models. These results indicate the importance of interaction between caspase-1, cytokines IL-1β and IL-18 in the host defense against S. schenckii infection, suggesting a participation the inflammasome in this response.

  10. Biphasic effect of IL-1beta on the activity of argininosuccinate synthetase in Caco-2 cells. Involvement of nitric oxide production.

    PubMed

    Brasse-Lagnel, Carole; Lavoinne, Alain; Fairand, Alain; Vavasseur, Karine; Deniel, Nicolas; Husson, Annie

    2006-06-01

    The expression of the argininosuccinate synthetase gene (ASS), the limiting enzyme of arginine synthesis, was previously shown to be rapidly induced by a short-term (4 h) exposure to IL-1beta in Caco-2 cells [Biochimie, 2005, 403-409]. The present report shows that, by contrast, a long-term (24 h) exposure to IL-1beta inhibited the ASS activity despite an increase in both specific mRNA level and protein amount, demonstrating a post-translational effect. Concerning the mechanism involved, we demonstrate that the inhibiting effect is linked to the production of nitric oxide (NO) induced by IL-1beta. Indeed, the inhibiting effect of IL-1beta was totally blocked in the presence of l-NMMA, an inhibitor of the inducible nitric oxide synthase, or by culturing the cells in an arginine-deprived medium. Moreover, a decrease in the ASS activity was induced by culturing the cells in the presence of SNAP, a NO donor. Conversely, blocking the action of NO by antioxidant agents, the stimulatory effect of IL-1beta on ASS activity was restored, as measured at 24 h. Finally, such an inhibiting effect of NO on ASS activity may be related, at least in part, to S-nitrosylation of the protein. The physiological relevance of the antagonistic effects of IL-1beta and NO on ASS is discussed.

  11. Nitric oxide induces heat-shock protein 70 expression in vascular smooth muscle cells via activation of heat shock factor 1.

    PubMed Central

    Xu, Q; Hu, Y; Kleindienst, R; Wick, G

    1997-01-01

    Current data suggest that nitric oxide (NO) is a double-edged sword that could result in relaxation and/or cytotoxicity of vascular smooth muscle cells (SMCs) via cGMP- dependent or -independent signal pathways. Stress or heat shock proteins (hsps) have been shown to be augmented in arterial SMCs during acute hypertension and atherosclerosis, both conditions that are believed to correlate with disturbed NO production. In the present study, we demonstrate that NO generated from sodium nitroprusside (SNP), S-nitroso-N-acetylpenicillamine, and spermine/nitric oxide complex leads to hsp70 induction in cultured SMCs. Western blot analysis demonstrated that hsp70 protein expression peaked between 6 and 12 h after treatment with SNP, and elevated protein levels were preceded by induction of hsp70 mRNA within 3 h. Induction of hsp70 mRNA was associated with the activation of heat shock transcription factor 1 (HSF1), suggesting that the response was regulated at the transcriptional level. HSF1 activation was completely blocked by hemoglobin, dithiothreitol, and cycloheximide, suggesting that the protein damage and nascent polypeptide formation induced by NO may initiate this activation. Furthermore, SMCs pretreated with heat shock (42 degrees C) for 30 min were significantly protected from death induced by NO. Thus, we provide evidence that NO induces hsp70 expression in SMCs via HSF1 activation. Induction of hsp70 could be important in protecting SMCs from injury resulting from NO stimulation. PMID:9276725

  12. Vascular nitric oxide: formation and function

    PubMed Central

    Jin, Richard C; Loscalzo, Joseph

    2010-01-01

    Nitric oxide (NO) is a structurally simple, highly versatile molecule that was originally discovered over 30 years ago as an endothelium-derived relaxing factor. In addition to its vasorelaxing effects, NO is now recognized as a key determinant of vascular health, exerting antiplatelet, antithrombotic, and anti-inflammatory properties within the vasculature. This short-lived molecule exerts its inhibitory effect on vascular smooth muscle cells and platelets largely through cyclic guanosine monophosphate-dependent mechanisms, resulting in a multitude of molecular effects by which platelet activation and aggregation are prevented. The biosynthesis of NO occurs via the catalytic activity of NO synthase, an oxidoreductase found in many cell types. NO insufficiency can be attributed to limited substrate/cofactor availability as well as interactions with reactive oxygen species. Impaired NO bioavailability represents the central feature of endothelial dysfunction, a common abnormality found in many vascular diseases. In this review, we present an overview of NO synthesis and biochemistry, discuss the mechanisms of action of NO in regulating platelet and endothelial function, and review the effects of vascular disease states on NO bioavailability. PMID:21572574

  13. Endothelial nitric oxide synthase in the microcirculation.

    PubMed

    Shu, Xiaohong; Keller, T C Stevenson; Begandt, Daniela; Butcher, Joshua T; Biwer, Lauren; Keller, Alexander S; Columbus, Linda; Isakson, Brant E

    2015-12-01

    Endothelial nitric oxide synthase (eNOS, NOS3) is responsible for producing nitric oxide (NO)--a key molecule that can directly (or indirectly) act as a vasodilator and anti-inflammatory mediator. In this review, we examine the structural effects of regulation of the eNOS enzyme, including post-translational modifications and subcellular localization. After production, NO diffuses to surrounding cells with a variety of effects. We focus on the physiological role of NO and NO-derived molecules, including microvascular effects on vessel tone and immune response. Regulation of eNOS and NO action is complicated; we address endogenous and exogenous mechanisms of NO regulation with a discussion of pharmacological agents used in clinical and laboratory settings and a proposed role for eNOS in circulating red blood cells.

  14. Effect of endogenous nitric oxide on mitochondrial respiration of rat hepatocytes in vitro and in vivo

    SciTech Connect

    Stadler, J.; Curran, R.D.; Ochoa, J.B.; Harbrecht, B.G.; Hoffman, R.A.; Simmons, R.L.; Billiar, T.R. )

    1991-02-01

    Nitric oxide, a highly reactive radical, was recently identified as an intermediate of L-arginine metabolism in mammalian cells. We have shown that nitric oxide synthesis is induced in vitro in cultured hepatocytes by supernatants from activated Kupffer cells or in vivo by injecting rats with nonviable Corynebacterium parvum. In both cases, nitric oxide biosynthesis in hepatocytes was associated with suppression of total protein synthesis. This study attempts to determine the effect of nitric oxide biosynthesis on the activity of specific hepatocytic mitochondrial enzymes and to determine whether inhibition of protein synthesis is caused by suppression of energy metabolism. Exposure of hepatocytes to supernatants from activated Kupffer cells led to a 30% decrease of aconitase (Krebs cycle) and complex I (mitochondrial electron transport chain) activity. Using NG-monomethyl-L-arginine, an inhibitor of nitric oxide synthesis, we demonstrated that the inhibition of mitochondrial aconitase activity was due, in part, to the action of nitric oxide. In contrast, in vivo nitric oxide synthesis of hepatocytes from Corynebacterium parvum-treated animals had no effect on mitochondrial respiration. This suggests that inhibition of protein synthesis by nitric oxide is not likely to be mediated by inhibition of energy metabolism.

  15. Nitric oxide: a regulator of eukaryotic initiation factor 2 kinases.

    PubMed

    Tong, Lingying; Heim, Rachel A; Wu, Shiyong

    2011-06-15

    Generation of nitric oxide (NO(•)) can upstream induce and downstream mediate the kinases that phosphorylate the α subunit of eukaryotic initiation factor 2 (eIF2α), which plays a critical role in regulating gene expression. There are four known eIF2α kinases (EIF2AKs), and NO(•) affects each one uniquely. Whereas NO(•) directly activates EIF2AK1 (HRI), it indirectly activates EIF2AK3 (PERK). EIF2AK4 (GCN2) is activated by depletion of l-arginine, which is used by nitric oxide synthase (NOS) during the production of NO(•). Finally EIF2AK2 (PKR), which can mediate inducible NOS expression and therefore NO(•) production, can also be activated by NO(•). The production of NO(•) and activation of EIF2AKs coordinately regulate physiological and pathological events such as innate immune response and cell apoptosis. PMID:21463677

  16. Structural insights into the role of iron-histidine bond cleavage in nitric oxide-induced activation of H-NOX gas sensor proteins.

    PubMed

    Herzik, Mark A; Jonnalagadda, Rohan; Kuriyan, John; Marletta, Michael A

    2014-10-01

    Heme-nitric oxide/oxygen (H-NOX) binding domains are a recently discovered family of heme-based gas sensor proteins that are conserved across eukaryotes and bacteria. Nitric oxide (NO) binding to the heme cofactor of H-NOX proteins has been implicated as a regulatory mechanism for processes ranging from vasodilation in mammals to communal behavior in bacteria. A key molecular event during NO-dependent activation of H-NOX proteins is rupture of the heme-histidine bond and formation of a five-coordinate nitrosyl complex. Although extensive biochemical studies have provided insight into the NO activation mechanism, precise molecular-level details have remained elusive. In the present study, high-resolution crystal structures of the H-NOX protein from Shewanella oneidensis in the unligated, intermediate six-coordinate and activated five-coordinate, NO-bound states are reported. From these structures, it is evident that several structural features in the heme pocket of the unligated protein function to maintain the heme distorted from planarity. NO-induced scission of the iron-histidine bond triggers structural rearrangements in the heme pocket that permit the heme to relax toward planarity, yielding the signaling-competent NO-bound conformation. Here, we also provide characterization of a nonheme metal coordination site occupied by zinc in an H-NOX protein.

  17. Structural insights into the role of iron–histidine bond cleavage in nitric oxide-induced activation of H-NOX gas sensor proteins

    PubMed Central

    Herzik, Mark A.; Jonnalagadda, Rohan; Kuriyan, John; Marletta, Michael A.

    2014-01-01

    Heme-nitric oxide/oxygen (H-NOX) binding domains are a recently discovered family of heme-based gas sensor proteins that are conserved across eukaryotes and bacteria. Nitric oxide (NO) binding to the heme cofactor of H-NOX proteins has been implicated as a regulatory mechanism for processes ranging from vasodilation in mammals to communal behavior in bacteria. A key molecular event during NO-dependent activation of H-NOX proteins is rupture of the heme–histidine bond and formation of a five-coordinate nitrosyl complex. Although extensive biochemical studies have provided insight into the NO activation mechanism, precise molecular-level details have remained elusive. In the present study, high-resolution crystal structures of the H-NOX protein from Shewanella oneidensis in the unligated, intermediate six-coordinate and activated five-coordinate, NO-bound states are reported. From these structures, it is evident that several structural features in the heme pocket of the unligated protein function to maintain the heme distorted from planarity. NO-induced scission of the iron–histidine bond triggers structural rearrangements in the heme pocket that permit the heme to relax toward planarity, yielding the signaling-competent NO-bound conformation. Here, we also provide characterization of a nonheme metal coordination site occupied by zinc in an H-NOX protein. PMID:25253889

  18. Near infrared radiation protects against oxygen-glucose deprivation-induced neurotoxicity by down-regulating neuronal nitric oxide synthase (nNOS) activity in vitro.

    PubMed

    Yu, Zhanyang; Li, Zhaoyu; Liu, Ning; Jizhang, Yunneng; McCarthy, Thomas J; Tedford, Clark E; Lo, Eng H; Wang, Xiaoying

    2015-06-01

    Near infrared radiation (NIR) has been shown to be neuroprotective against neurological diseases including stroke and brain trauma, but the underlying mechanisms remain poorly understood. In the current study we aimed to investigate the hypothesis that NIR may protect neurons by attenuating oxygen-glucose deprivation (OGD)-induced nitric oxide (NO) production and modulating cell survival/death signaling. Primary mouse cortical neurons were subjected to 4 h OGD and NIR was applied at 2 h reoxygenation. OGD significantly increased NO level in primary neurons compared to normal control, which was significantly ameliorated by NIR at 5 and 30 min post-NIR. Neither OGD nor NIR significantly changed neuronal nitric oxide synthase (nNOS) mRNA or total protein levels compared to control groups. However, OGD significantly increased nNOS activity compared to normal control, and this effect was significantly diminished by NIR. Moreover, NIR significantly ameliorated the neuronal death induced by S-Nitroso-N-acetyl-DL-penicillamine (SNAP), a NO donor. Finally, NIR significantly rescued OGD-induced suppression of p-Akt and Bcl-2 expression, and attenuated OGD-induced upregulation of Bax, BAD and caspase-3 activation. These results suggest NIR may protect against OGD at least partially through reducing NO production by down-regulating nNOS activity, and modulating cell survival/death signaling.

  19. Nitric oxide protects neuroblastoma cells from apoptosis induced by serum deprivation through cAMP-response element-binding protein (CREB) activation.

    PubMed

    Ciani, Elisabetta; Guidi, Sandra; Della Valle, Giuliano; Perini, Giovanni; Bartesaghi, Renata; Contestabile, Antonio

    2002-12-20

    The transcription factor cAMP-response element-binding protein (CREB) mediates survival in many cells, including neurons. Recently, death of cerebellar granule neurons due to nitric oxide (NO) deprivation was shown to be accompanied by down-regulation of CREB activity (). We now provide evidence that overproduction of endogenous NO or supplementation with exogenous NO renders SK-N-BE human neuroblastoma cells more resistant to apoptosis induced by serum deprivation. Parental cells underwent apoptosis after 24 h of serum deprivation, an outcome largely absent in clones overexpressing human neuronal nitric oxide synthase (nNOS). This protective effect was reversed by the inhibition of NOS itself or soluble guanylyl cyclase, pointing at cGMP as an intermediate effector of NO-mediated rescue. A slow-releasing NO donor protected parental cells to a significant extent, thus confirming the survival effect of NO. The impaired viability of serum-deprived parental cells was accompanied by a strong decrease of CREB phosphorylation and transcriptional activity, effects significantly attenuated in nNOS-overexpressing clones. To confirm the role of CREB in survival, the ectopic expression of CREB and/or protein kinase A largely counteracted serum deprivation-induced cell death of SK-N-BE cells, whereas transfection with a CREB negative mutant was ineffective. These experiments indicate that CREB activity is an important step for NO-mediated survival in neuronal cells.

  20. Nitric oxide protects neuroblastoma cells from apoptosis induced by serum deprivation through cAMP-response element-binding protein (CREB) activation.

    PubMed

    Ciani, Elisabetta; Guidi, Sandra; Della Valle, Giuliano; Perini, Giovanni; Bartesaghi, Renata; Contestabile, Antonio

    2002-12-20

    The transcription factor cAMP-response element-binding protein (CREB) mediates survival in many cells, including neurons. Recently, death of cerebellar granule neurons due to nitric oxide (NO) deprivation was shown to be accompanied by down-regulation of CREB activity (). We now provide evidence that overproduction of endogenous NO or supplementation with exogenous NO renders SK-N-BE human neuroblastoma cells more resistant to apoptosis induced by serum deprivation. Parental cells underwent apoptosis after 24 h of serum deprivation, an outcome largely absent in clones overexpressing human neuronal nitric oxide synthase (nNOS). This protective effect was reversed by the inhibition of NOS itself or soluble guanylyl cyclase, pointing at cGMP as an intermediate effector of NO-mediated rescue. A slow-releasing NO donor protected parental cells to a significant extent, thus confirming the survival effect of NO. The impaired viability of serum-deprived parental cells was accompanied by a strong decrease of CREB phosphorylation and transcriptional activity, effects significantly attenuated in nNOS-overexpressing clones. To confirm the role of CREB in survival, the ectopic expression of CREB and/or protein kinase A largely counteracted serum deprivation-induced cell death of SK-N-BE cells, whereas transfection with a CREB negative mutant was ineffective. These experiments indicate that CREB activity is an important step for NO-mediated survival in neuronal cells. PMID:12368293

  1. Endogenous nitric oxide generation in protoplast chloroplasts.

    PubMed

    Tewari, Rajesh Kumar; Prommer, Judith; Watanabe, Masami

    2013-01-01

    KEY MESSAGE : NO generation is studied in the protoplast chloroplasts. NO, ONOO ( - ) and ROS (O ( 2 ) ( - ) and H ( 2 ) O ( 2 ) ) are generated in chloroplasts. Nitric oxide synthase-like protein appears to be involved in NO generation. Nitric oxide stimulates chlorophyll biosynthesis and chloroplast differentiation. The present study was conducted to better understand the process of NO generation in the leaf chloroplasts and protoplasts. NO, peroxynitrite and superoxide anion were investigated in the protoplasts and isolated chloroplasts using specific dyes, confocal laser scanning and light microscopy. The level of NO was highest after protoplast isolation and subsequently decreased during culture. Suppression of NO signal in the presence of PTIO, suggests that diaminofluorescein-2 diacetate (DAF-2DA) detected NO. Detection of peroxynitrite, a reaction product of NO and superoxide anion, further suggests NO generation. Moreover, generation of NO and peroxynitrite in the chloroplasts of wild-type Arabidopsis and their absence or weak signals in the leaf-derived protoplasts of Atnoa1 mutants confirmed the reactivity of DAF-2DA and aminophenyl fluorescein to NO and peroxynitrite, respectively. Isolated chloroplasts also showed signal of NO. Suppression of NO signal in the presence of 100 μM nitric oxide synthase inhibitors [L-NNA, Nω-nitro-L-arginine and PBIT, S,S'-1,3-phenylene-bis(1,2-ethanediyl)-bis-isothiourea] revealed that nitric oxide synthase-like system is involved in NO synthesis. Suppression of NO signal in the protoplasts isolated in the presence of cycloheximide suggests de novo synthesis of NO generating protein during the process of protoplast isolation. Furthermore, the lack of inhibition of NO production by sodium tungstate (250 μM) and inhibition by L-NNA, and PBIT suggest involvement NOS-like protein, but not nitrate reductase, in NO generation in the leaf chloroplasts and protoplasts.

  2. Nitric oxide and the control of reproduction.

    PubMed

    Dixit, V D; Parvizi, N

    2001-01-31

    The free radical gas, nitric oxide is now known to be an important biological messenger in animals. Signal transmission by a gas that is produced by one cell, penetrates through membranes and regulates the function of another cell, represents new principles for signalling in biological systems. Nitric oxide is synthesised from L-arginine by enzyme nitric oxide synthase, which exists in multiple isoforms in a wide range of mammalian cells. Studies conducted in recent years point at a strong influence of NO in a wide range of reproductive functions. It is implicated in the control of gonadotrophin secretion at both hypothalamic and hypophyseal levels, LH surge mechanism, sexual behaviour, estradiol synthesis, follicle survival and ovulation. While considerable work lies ahead in unravelling the role of NO at the peripheral, cellular and molecular level in the domestic animal reproduction, findings presented in this review provide a general overview of growing appreciation of NO as a vital molecule controlling hypothalamic-pituitary-gonadal (HPG) axis.

  3. Biological nitric oxide signalling: chemistry and terminology

    PubMed Central

    Heinrich, Tassiele A; da Silva, Roberto S; Miranda, Katrina M; Switzer, Christopher H; Wink, David A; Fukuto, Jon M

    2013-01-01

    Biological nitrogen oxide signalling and stress is an area of extreme clinical, pharmacological, toxicological, biochemical and chemical research interest. The utility of nitric oxide and derived species as signalling agents is due to their novel and vast chemical interactions with a variety of biological targets. Herein, the chemistry associated with the interaction of the biologically relevant nitrogen oxide species with fundamental biochemical targets is discussed. Specifically, the chemical interactions of nitrogen oxides with nucleophiles (e.g. thiols), metals (e.g. hemeproteins) and paramagnetic species (e.g. dioxygen and superoxide) are addressed. Importantly, the terms associated with the mechanisms by which NO (and derived species) react with their respective biological targets have been defined by numerous past chemical studies. Thus, in order to assist researchers in referring to chemical processes associated with nitrogen oxide biology, the vernacular associated with these chemical interactions is addressed. PMID:23617570

  4. Nitric oxide negatively regulates mammalian adult neurogenesis

    NASA Astrophysics Data System (ADS)

    Packer, Michael A.; Stasiv, Yuri; Benraiss, Abdellatif; Chmielnicki, Eva; Grinberg, Alexander; Westphal, Heiner; Goldman, Steven A.; Enikolopov, Grigori

    2003-08-01

    Neural progenitor cells are widespread throughout the adult central nervous system but only give rise to neurons in specific loci. Negative regulators of neurogenesis have therefore been postulated, but none have yet been identified as subserving a significant role in the adult brain. Here we report that nitric oxide (NO) acts as an important negative regulator of cell proliferation in the adult mammalian brain. We used two independent approaches to examine the function of NO in adult neurogenesis. In a pharmacological approach, we suppressed NO production in the rat brain by intraventricular infusion of an NO synthase inhibitor. In a genetic approach, we generated a null mutant neuronal NO synthase knockout mouse line by targeting the exon encoding active center of the enzyme. In both models, the number of new cells generated in neurogenic areas of the adult brain, the olfactory subependyma and the dentate gyrus, was strongly augmented, which indicates that division of neural stem cells in the adult brain is controlled by NO and suggests a strategy for enhancing neurogenesis in the adult central nervous system.

  5. Role of Nitric Oxide in the Regulation of Renin and Vasopressin Secretion

    NASA Technical Reports Server (NTRS)

    Reid, Ian A.

    1994-01-01

    Research during recent years has established nitric oxide as a unique signaling molecule that plays important roles in the regulation of the cardiovascular, nervous, immune, and other systems. Nitric oxide has also been implicated in the control of the secretion of hormones by the pancreas, hypothalamus, and anterior pituitary gland, and evidence is accumulating that it contributes to the regulation of the secretion of renin and vasopressin, hormones that play key roles in the control of sodium and water balance. Several lines of evidence have implicated nitric oxide in the control of renin secretion. The enzyme nitric oxide synthase is present in vascular and tubular elements of the kidney, particularly in cells of the macula densa, a structure that plays an important role in the control of renin secretion. Guanylyl cyclase, a major target for nitric oxide, is also present in the kidney. Drugs that inhibit nitric oxide synthesis generally suppress renin release in vivo and in vitro, suggesting a stimulatory role for the L-arginine/nitric oxide pathway in the control of renin secretion. Under some conditions, however, blockade of nitric oxide synthesis increases renin secretion. Recent studies indicate that nitric oxide not only contributes to the regulation of basal renin secretion, but also participates in the renin secretory responses to activation of the renal baroreceptor, macula densa, and beta adrenoceptor mechanisms that regulate renin secretion. Histochemical and immunocytochemical studies have revealed the presence of nitric oxide synthase in the supraoptic and paraventricular nuclei of the hypothalamus and in the posterior pituitary gland. Colocalization of nitric oxide synthase and vasopressin has been demonstrated in some hypothalamic neurons. Nitric oxide synthase activity in the hypothalamus and pituitary is increased by maneuvers known to stimulate vasopressin secretion, including salt loading and dehydration, Administration of L-arginine and nitric

  6. Role of nitric oxide in parasitic infections.

    PubMed Central

    James, S L

    1995-01-01

    Nitric oxide is produced by a number of different cell types in response to cytokine stimulation and thus has been found to play a role in immunologically mediated protection against a growing list of protozoan and helminth parasites in vitro and in animal models. The biochemical basis of its effects on the parasite targets appears to involve primarily inactivation of enzymes crucial to energy metabolism and growth, although it has other biologic activities as well. NO is produced not only by macrophages and macrophage-like cells commonly associated with the effector arm of cell-mediated immune reactivity but also by cells commonly considered to lie outside the immunologic network, such as hepatocytes and endothelial cells, which are intimately involved in the life cycle of a number of parasites. NO production is stimulated by gamma interferon in combination with tumor necrosis factor alpha or other secondary activation signals and is regulated by a number of cytokines (especially interleukin-4, interleukin-10, and transforming growth factor beta) and other mediators, as well as through its own inherent inhibitory activity. The potential for design of prevention and/or intervention approaches against parasitic infection (e.g., vaccination or combination chemo- and immunotherapy strategies) on the basis of induction of cell-mediated immunity and NO production appears to be great, but the possible pathogenic consequences of overproduction of NO must be taken into account. Moreover, more research on the role and regulation of NO in human parasitic infection is needed before its possible clinical relevance can be determined. PMID:8531884

  7. Octacalcium phosphate crystals directly stimulate expression of inducible nitric oxide synthase through p38 and JNK mitogen-activated protein kinases in articular chondrocytes

    PubMed Central

    Ea, Hang-Korng; Uzan, Benjamin; Rey, Christian; Lioté, Frédéric

    2005-01-01

    Basic calcium phosphate (BCP) crystals, including hydroxyapatite, octacalcium phosphate (OCP) and carbonate-apatite, have been associated with severe osteoarthritis and several degenerative arthropathies. Most studies have considered the chondrocyte to be a bystander in the pathogenesis of calcium crystal deposition disease, assuming that synovial cell cytokines were the only triggers of chondrocyte activation. In the present study we identified direct activation of articular chondrocytes by OCP crystals, which are the BCP crystals with the greatest potential for inducing inflammation. OCP crystals induced nitric oxide (NO) production and inducible nitric oxide synthase (NOS) mRNA expression by isolated articular chondrocytes and cartilage fragments, in a dose-dependent manner and with variations over time. OCP crystals also induced IL-1β mRNA expression. Using pharmacological and cytokine inhibitors, we observed that OCP crystals induced NO production and inducible NOS mRNA activation were regulated at both the transcriptional and the translational levels; were independent from IL-1β gene activation; and involved p38 and c-Jun amino-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathways, as further confirmed by OCP crystal-induced p38 and JNK MAPK phosphorylation. Taken together, our data suggest that the transcriptional inducible NOS response to OCP crystals involved both the p38 and the JNK MAPK pathways, probably under the control of activator protein-1. NO, a major mediator of cartilage degradation, can be directly produced by BCP crystals in chondrocytes. Together with synovial activation, this direct mechanism may be important in the pathogenesis of destructive arthropathies triggered by microcrystals. PMID:16207333

  8. A Zebrafish Drug-Repurposing Screen Reveals sGC-Dependent and sGC-Independent Pro-Inflammatory Activities of Nitric Oxide.

    PubMed

    Wittmann, Christine; Reischl, Markus; Shah, Asmi H; Kronfuss, Eva; Mikut, Ralf; Liebel, Urban; Grabher, Clemens

    2015-01-01

    Tissue injury and infection trigger innate immune responses. However, dysregulation may result in chronic inflammation and is commonly treated with corticosteroids and non-steroidal anti-inflammatory drugs. Unfortunately, long-term administration of both therapeutic classes can cause unwanted side effects. To identify alternative immune-modulatory compounds we have previously established a novel screening method using zebrafish larvae. Using this method we here present results of an in vivo high-content drug-repurposing screen, identifying 63 potent anti-inflammatory drugs that are in clinical use for other indications. Our approach reveals a novel pro-inflammatory role of nitric oxide. Nitric oxide affects leukocyte recruitment upon peripheral sensory nervous system or epithelial injury in zebrafish larvae both via soluble guanylate cyclase and in a soluble guanylate cyclase -independent manner through protein S-nitrosylation. Together, we show that our screening method can help to identify novel immune-modulatory activities and provide new mechanistic insights into the regulation of inflammatory processes.

  9. Nitric Oxide Mediates the Stress Response Induced by Diatom Aldehydes in the Sea Urchin Paracentrotus lividus

    PubMed Central

    Romano, Giovanna; Costantini, Maria; Buttino, Isabella; Ianora, Adrianna; Palumbo, Anna

    2011-01-01

    Diatoms are ubiquitous and abundant primary producers that have been traditionally considered as a beneficial food source for grazers and for the transfer of carbon through marine food webs. However, many diatom species produce polyunsaturated aldehydes that disrupt development in the offspring of grazers that feed on these unicellular algae. Here we provide evidence that production of the physiological messenger nitric oxide increases after treatment with the polyunsaturated aldehyde decadienal in embryos of the sea urchin Paracentrotus lividus. At high decadienal concentrations, nitric oxide mediates initial apoptotic events leading to loss of mitochondrial functionality through the generation of peroxynitrite. At low decadienal concentrations, nitric oxide contributes to the activation of hsp70 gene expression thereby protecting embryos against the toxic effects of this aldehyde. When nitric oxide levels were lowered by inhibiting nitric oxide synthase activity, the expression of hsp70 in swimming blastula decreased and the proportion of abnormal plutei increased. However, in later pluteus stages nitric oxide was no longer able to exert this protective function: hsp70 and nitric oxide synthase expression decreased with a consequent increase in the expression of caspase-8. Our findings that nitric oxide production increases rapidly in response to a toxic exogenous stimulus opens new perspectives on the possible role of this gas as an important messenger to environmental stress in sea urchins and for understanding the cellular mechanisms underlying toxicity during diatom blooms. PMID:22022485

  10. Nitric oxide mediates the stress response induced by diatom aldehydes in the sea urchin Paracentrotus lividus.

    PubMed

    Romano, Giovanna; Costantini, Maria; Buttino, Isabella; Ianora, Adrianna; Palumbo, Anna

    2011-01-01

    Diatoms are ubiquitous and abundant primary producers that have been traditionally considered as a beneficial food source for grazers and for the transfer of carbon through marine food webs. However, many diatom species produce polyunsaturated aldehydes that disrupt development in the offspring of grazers that feed on these unicellular algae. Here we provide evidence that production of the physiological messenger nitric oxide increases after treatment with the polyunsaturated aldehyde decadienal in embryos of the sea urchin Paracentrotus lividus. At high decadienal concentrations, nitric oxide mediates initial apoptotic events leading to loss of mitochondrial functionality through the generation of peroxynitrite. At low decadienal concentrations, nitric oxide contributes to the activation of hsp70 gene expression thereby protecting embryos against the toxic effects of this aldehyde. When nitric oxide levels were lowered by inhibiting nitric oxide synthase activity, the expression of hsp70 in swimming blastula decreased and the proportion of abnormal plutei increased. However, in later pluteus stages nitric oxide was no longer able to exert this protective function: hsp70 and nitric oxide synthase expression decreased with a consequent increase in the expression of caspase-8. Our findings that nitric oxide production increases rapidly in response to a toxic exogenous stimulus opens new perspectives on the possible role of this gas as an important messenger to environmental stress in sea urchins and for understanding the cellular mechanisms underlying toxicity during diatom blooms. PMID:22022485

  11. Investigation of the role of nitric oxide and cyclic GMP in both the activation and inhibition of human neutrophils

    PubMed Central

    Wanikiat, P; Woodward, D F; Armstrong, R A

    1997-01-01

    The aim of this study was to establish the role of nitric oxide (NO) and cyclic GMP in chemotaxis and superoxide anion generation (SAG) by human neutrophils, by use of selective inhibitors of NO and cyclic GMP pathways. In addition, inhibition of neutrophil chemotaxis by NO releasing compounds and increases in neutrophil nitrate/nitrite and cyclic GMP levels were examined. The ultimate aim of this work was to resolve the paradox that NO both activates and inhibits human neutrophils. A role for NO as a mediator of N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced chemotaxis was supported by the finding that the NO synthase (NOS) inhibitor L-NMMA (500 μM) inhibited chemotaxis; EC50 for fMLP 28.76±5.62 and 41.13±4.77 pmol/106 cells with and without L-NMMA, respectively. Similarly the NO scavenger carboxy-PTIO (100 μM) inhibited chemotaxis; EC50 for fMLP 19.71±4.23 and 31.68±8.50 pmol/106 cells with and without carboxy-PTIO, respectively. A role for cyclic GMP as a mediator of chemotaxis was supported by the finding that the guanylyl cyclase inhibitor LY 83583 (100 μM) completely inhibited chemotaxis and suppressed the maximal response; EC50 for fMLP 32.53±11.18 and 85.21±15.14 pmol/106 cells with and without LY 83583, respectively. The same pattern of inhibition was observed with the G-kinase inhibitor KT 5823 (10 μM); EC50 for fMLP 32.16±11.35 and >135 pmol/106 cells with and without KT 5823, respectively. The phosphatase inhibitor, 2,3-diphosphoglyceric acid (DPG) (100 μM) which inhibits phospholipase D, attenuated fMLP-induced chemotaxis; EC50 for fMLP 19.15±4.36 and 61.52±16.2 pmol/106 cells with and without DPG, respectively. Although the NOS inhibitors L-NMMA and L-canavanine (500 μM) failed to inhibit fMLP-induced SAG, carboxy-PTIO caused significant inhibition (EC50 for fMLP 36.15±7.43 and 86.31±14.06 nM and reduced the maximal response from 22.14±1.5 to 9.8±1.6 nmol O2−/106 cells/10 min with and without

  12. In-vitro susceptibility of hydatid cysts of Echinococcus granulosus to nitric oxide and the effect of the laminated layer on nitric oxide production.

    PubMed

    Steers, N J; Rogan, M T; Heath, S

    2001-08-01

    Murine hydatid cysts of Echinococcus granulosus were incubated in vitro in the presence of nitric oxide produced from S-nitroso-N-acetylpenicillamine (SNAP) or interferon-gamma activated peritoneal macrophages. In both situations, evidence of cyst damage and death was observed by microscopy in over 77% of cysts after 3 days, indicating that intact hydatid cysts could be susceptible to a Th1 driven macrophage attack. A crude extract of the laminated layer from cysts was found to be able to reduce the production of nitric oxide from activated macrophages in vitro and in vivo and this may have been due to phagocytosis of laminated layer fragments by the macrophages. The results indicate that, although cysts may be susceptible to the effects of nitric oxide, the laminated layer may be involved in downregulating nitric oxide production.

  13. Inhaled nitric oxide in chronic obstructive lung disease

    SciTech Connect

    Tiihonen, J.; Hakola, P.; Paanila, J.; Turtiainen . Dept. of Forensic Psychiatry)

    1993-01-30

    During an investigation of the effect of nitric oxide on the pulmonary circulation the authors had the opportunity to give nitric oxide to a patient with longstanding obstructive airway disease, with successful results. A 72-year-old man with chronic obstructive pulmonary disease was referred to the institution for assessment of pulmonary vascular reactivity to acetylcholine and nitric oxide. Acetylcholine was infused into the main pulmonary artery followed 15 min later by an inhalation of 80 parts per million (ppm) nitric oxide. Heart rate and systemic arterial and pulmonary arterial pressures were continuously monitored. Throughout the study the inspired oxygen concentration was kept constant at 98%. Nitrogen dioxide and nitric oxide concentrations were monitored while nitric oxide was delivered. The infusion of acetylcholine resulted in a small increase in pulmonary artery pressure and pulmonary vascular resistance. Nitric oxide produced a substantial fall in pulmonary artery pressure and pulmonary vascular resistance with a concomitant increase in systemic arterial oxygen tension. These results suggest that endothelium-dependent relaxation of the pulmonary vasculature was impaired in the patient and that exogenous nitric oxide was an effective pulmonary vasodilator. In-vitro investigation of explanted airways disease suggests not only that endothelium-dependent pulmonary artery relaxation is impaired but also that the dysfunction is related to pre-existing hypoxemia and hypercapnia. Nitric oxide inhibits proliferation of cultured vascular smooth muscle cells and might alter the pulmonary vascular remodeling characteristic of patients with chronic obstructive airways disease.

  14. Processes regulating nitric oxide emissions from soils.

    PubMed

    Pilegaard, Kim

    2013-07-01

    Nitric oxide (NO) is a reactive gas that plays an important role in atmospheric chemistry by influencing the production and destruction of ozone and thereby the oxidizing capacity of the atmosphere. NO also contributes by its oxidation products to the formation of acid rain. The major sources of NO in the atmosphere are anthropogenic emissions (from combustion of fossil fuels) and biogenic emission from soils. NO is both produced and consumed in soils as a result of biotic and abiotic processes. The main processes involved are microbial nitrification and denitrification, and chemodenitrification. Thus, the net result is complex and dependent on several factors such as nitrogen availability, organic matter content, oxygen status, soil moisture, pH and temperature. This paper reviews recent knowledge on processes forming NO in soils and the factors controlling its emission to the atmosphere. Schemes for simulating these processes are described, and the results are discussed with the purpose of scaling up to global emission.

  15. Processes regulating nitric oxide emissions from soils.

    PubMed

    Pilegaard, Kim

    2013-07-01

    Nitric oxide (NO) is a reactive gas that plays an important role in atmospheric chemistry by influencing the production and destruction of ozone and thereby the oxidizing capacity of the atmosphere. NO also contributes by its oxidation products to the formation of acid rain. The major sources of NO in the atmosphere are anthropogenic emissions (from combustion of fossil fuels) and biogenic emission from soils. NO is both produced and consumed in soils as a result of biotic and abiotic processes. The main processes involved are microbial nitrification and denitrification, and chemodenitrification. Thus, the net result is complex and dependent on several factors such as nitrogen availability, organic matter content, oxygen status, soil moisture, pH and temperature. This paper reviews recent knowledge on processes forming NO in soils and the factors controlling its emission to the atmosphere. Schemes for simulating these processes are described, and the results are discussed with the purpose of scaling up to global emission. PMID:23713124

  16. Processes regulating nitric oxide emissions from soils

    PubMed Central

    Pilegaard, Kim

    2013-01-01

    Nitric oxide (NO) is a reactive gas that plays an important role in atmospheric chemistry by influencing the production and destruction of ozone and thereby the oxidizing capacity of the atmosphere. NO also contributes by its oxidation products to the formation of acid rain. The major sources of NO in the atmosphere are anthropogenic emissions (from combustion of fossil fuels) and biogenic emission from soils. NO is both produced and consumed in soils as a result of biotic and abiotic processes. The main processes involved are microbial nitrification and denitrification, and chemodenitrification. Thus, the net result is complex and dependent on several factors such as nitrogen availability, organic matter content, oxygen status, soil moisture, pH and temperature. This paper reviews recent knowledge on processes forming NO in soils and the factors controlling its emission to the atmosphere. Schemes for simulating these processes are described, and the results are discussed with the purpose of scaling up to global emission. PMID:23713124

  17. Laminar shear flow increases hydrogen sulfide and activates a nitric oxide producing signaling cascade in endothelial cells.

    PubMed

    Huang, Bin; Chen, Chang-Ting; Chen, Chi-Shia; Wang, Yun-Ming; Hsieh, Hsyue-Jen; Wang, Danny Ling

    2015-09-01

    Laminar shear flow triggers a signaling cascade that maintains the integrity of endothelial cells (ECs). Hydrogen sulfide (H2S), a new gasotransmitter is regarded as an upstream regulator of nitric oxide (NO). Whether the H2S-generating enzymes are correlated to the enzymes involved in NO production under shear flow conditions remains unclear as yet. In the present study, the cultured ECs were subjected to a constant shear flow (12 dyn/cm(2)) in a parallel flow chamber system. We investigated the expression of three key enzymes for H2S biosynthesis, cystathionine-γ-lyase (CSE), cystathionine-β-synthase (CBS), and 3-mercapto-sulfurtransferase (3-MST). Shear flow markedly increased the level of 3-MST. Shear flow enhanced the production of H2S was determined by NBD-SCN reagent that can bind to cysteine/homocystein. Exogenous treatment of NaHS that can release gaseous H2S, ECs showed an increase of phosphorylation in Akt(S473), ERK(T202/Y204) and eNOS(S1177). This indicated that H2S can trigger the NO-production signaling cascade. Silencing of CSE, CBS and 3-MST genes by siRNA separately attenuated the phosphorylation levels of Akt(S473) and eNOS(S1177) under shear flow conditions. The particular mode of shear flow increased H2S production. The interplay between H2S and NO-generating enzymes were discussed in the present study. PMID:26212441

  18. Nitric oxide and plant iron homeostasis.

    PubMed

    Buet, Agustina; Simontacchi, Marcela

    2015-03-01

    Like all living organisms, plants demand iron (Fe) for important biochemical and metabolic processes. Internal imbalances, as a consequence of insufficient or excess Fe in the environment, lead to growth restriction and affect crop yield. Knowledge of signals and factors affecting each step in Fe uptake from the soil and distribution (long-distance transport, remobilization from old to young leaves, and storage in seeds) is necessary to improve our understanding of plant mineral nutrition. In this context, the role of nitric oxide (NO) is discussed as a key player in maintaining Fe homeostasis through its cross talk with hormones, ferritin, and frataxin and the ability to form nitrosyl-iron complexes.

  19. Process-driven bacterial community dynamics are key to cured meat colour formation by coagulase-negative staphylococci via nitrate reductase or nitric oxide synthase activities.

    PubMed

    Sánchez Mainar, María; Leroy, Frédéric

    2015-11-01

    The cured colour of European raw fermented meats is usually achieved by nitrate-into-nitrite reduction by coagulase-negative staphylococci (CNS), subsequently generating nitric oxide to form the relatively stable nitrosomyoglobin pigment. The present study aimed at comparing this classical curing procedure, based on nitrate reductase activity, with a potential alternative colour formation mechanism, based on nitric oxide synthase (NOS) activity, under different acidification profiles. To this end, meat models with and without added nitrate were fermented with cultures of an acidifying strain (Lactobacillus sakei CTC 494) and either a nitrate-reducing Staphylococcus carnosus strain or a rare NOS-positive CNS strain (Staphylococcus haemolyticus G110), or by relying on the background microbiota. Satisfactory colour was obtained in the models prepared with added nitrate and S. carnosus. In the presence of nitrate but absence of added CNS, however, cured colour was only obtained when L. sakei CTC 494 was also omitted. This was ascribed to the pH dependency of the emerging CNS background microbiota, selecting for nitrate-reducing Staphylococcus equorum strains at mild acidification conditions but for Staphylococcus saprophyticus strains with poor colour formation capability when the pH decrease was more rapid. This reliance of colour formation on the composition of the background microbiota was further explored by a side experiment, demonstrating the heterogeneity in nitrate reduction of a set of 88 CNS strains from different species. Finally, in all batches prepared with S. haemolyticus G110, colour generation failed as the strain was systematically outcompeted by the background microbiota, even when imposing milder acidification profiles. Thus, when aiming at colour formation through CNS metabolism, technological processing can severely interfere with the composition and functionality of the meat-associated CNS communities, for both nitrate reductase and NOS activities

  20. Activated Macrophages as a Novel Determinant of Tumor Cell Radioresponse: The Role of Nitric Oxide-Mediated Inhibition of Cellular Respiration and Oxygen Sparing

    SciTech Connect

    Jiang Heng; De Ridder, Mark; Verovski, Valeri N.; Sonveaux, Pierre; Jordan, Benedicte F.; Law, Kalun; Monsaert, Christinne; Van den Berge, Dirk L.; Verellen, Dirk; Feron, Olivier; Gallez, Bernard; Storme, Guy A.

    2010-04-15

    Purpose: Nitric oxide (NO), synthesized by the inducible nitric oxide synthase (iNOS), is known to inhibit metabolic oxygen consumption because of interference with mitochondrial respiratory activity. This study examined whether activation of iNOS (a) directly in tumor cells or (b) in bystander macrophages may improve radioresponse through sparing of oxygen. Methods and Materials: EMT-6 tumor cells and RAW 264.7 macrophages were exposed to bacterial lipopolysaccharide plus interferon-gamma, and examined for iNOS expression by reverse transcription polymerase chain reaction, Western blotting and enzymatic activity. Tumor cells alone, or combined with macrophages were subjected to metabolic hypoxia and analyzed for radiosensitivity by clonogenic assay, and for oxygen consumption by electron paramagnetic resonance and a Clark-type electrode. Results: Both tumor cells and macrophages displayed a coherent picture of iNOS induction at transcriptional/translational levels and NO/nitrite production, whereas macrophages showed also co-induction of the inducible heme oxygenase-1, which is associated with carbon monoxide (CO) and bilirubin production. Activation of iNOS in tumor cells resulted in a profound oxygen sparing and a 2.3-fold radiosensitization. Bystander NO-producing, but not CO-producing, macrophages were able to block oxygen consumption by 1.9-fold and to radiosensitize tumor cells by 2.2-fold. Both effects could be neutralized by aminoguanidine, a metabolic iNOS inhibitor. An improved radioresponse was clearly observed at macrophages to tumor cells ratios ranging between 1:16 to 1:1. Conclusions: Our study is the first, as far as we are aware, to provide evidence that iNOS may induce radiosensitization through oxygen sparing, and illuminates NO-producing macrophages as a novel determinant of tumor cell radioresponse within the hypoxic tumor microenvironment.

  1. Process-driven bacterial community dynamics are key to cured meat colour formation by coagulase-negative staphylococci via nitrate reductase or nitric oxide synthase activities.

    PubMed

    Sánchez Mainar, María; Leroy, Frédéric

    2015-11-01

    The cured colour of European raw fermented meats is usually achieved by nitrate-into-nitrite reduction by coagulase-negative staphylococci (CNS), subsequently generating nitric oxide to form the relatively stable nitrosomyoglobin pigment. The present study aimed at comparing this classical curing procedure, based on nitrate reductase activity, with a potential alternative colour formation mechanism, based on nitric oxide synthase (NOS) activity, under different acidification profiles. To this end, meat models with and without added nitrate were fermented with cultures of an acidifying strain (Lactobacillus sakei CTC 494) and either a nitrate-reducing Staphylococcus carnosus strain or a rare NOS-positive CNS strain (Staphylococcus haemolyticus G110), or by relying on the background microbiota. Satisfactory colour was obtained in the models prepared with added nitrate and S. carnosus. In the presence of nitrate but absence of added CNS, however, cured colour was only obtained when L. sakei CTC 494 was also omitted. This was ascribed to the pH dependency of the emerging CNS background microbiota, selecting for nitrate-reducing Staphylococcus equorum strains at mild acidification conditions but for Staphylococcus saprophyticus strains with poor colour formation capability when the pH decrease was more rapid. This reliance of colour formation on the composition of the background microbiota was further explored by a side experiment, demonstrating the heterogeneity in nitrate reduction of a set of 88 CNS strains from different species. Finally, in all batches prepared with S. haemolyticus G110, colour generation failed as the strain was systematically outcompeted by the background microbiota, even when imposing milder acidification profiles. Thus, when aiming at colour formation through CNS metabolism, technological processing can severely interfere with the composition and functionality of the meat-associated CNS communities, for both nitrate reductase and NOS activities

  2. Nitric oxide synthases: structure, function and inhibition.

    PubMed Central

    Alderton, W K; Cooper, C E; Knowles, R G

    2001-01-01

    This review concentrates on advances in nitric oxide synthase (NOS) structure, function and inhibition made in the last seven years, during which time substantial advances have been made in our understanding of this enzyme family. There is now information on the enzyme structure at all levels from primary (amino acid sequence) to quaternary (dimerization, association with other proteins) structure. The crystal structures of the oxygenase domains of inducible NOS (iNOS) and vascular endothelial NOS (eNOS) allow us to interpret other information in the context of this important part of the enzyme, with its binding sites for iron protoporphyrin IX (haem), biopterin, L-arginine, and the many inhibitors which interact with them. The exact nature of the NOS reaction, its mechanism and its products continue to be sources of controversy. The role of the biopterin cofactor is now becoming clearer, with emerging data implicating one-electron redox cycling as well as the multiple allosteric effects on enzyme activity. Regulation of the NOSs has been described at all levels from gene transcription to covalent modification and allosteric regulation of the enzyme itself. A wide range of NOS inhibitors have been discussed, interacting with the enzyme in diverse ways in terms of site and mechanism of inhibition, time-dependence and selectivity for individual isoforms, although there are many pitfalls and misunderstandings of these aspects. Highly selective inhibitors of iNOS versus eNOS and neuronal NOS have been identified and some of these have potential in the treatment of a range of inflammatory and other conditions in which iNOS has been implicated. PMID:11463332

  3. Lipoteichoic Acid-Induced Nitric Oxide Production Depends on the Activation of Platelet-Activating Factor Receptor and Jak21

    PubMed Central

    Han, Seung Hyun; Kim, Je Hak; Seo, Ho Seong; Martin, Michael H.; Chung, Gook-Hyun; Michalek, Suzanne M.; Nahm, Moon H.

    2006-01-01

    NO production by macrophages in response to lipoteichoic acid (LTA) and a synthetic lipopeptide (Pam3CSK4) was investigated. LTA and Pam3CSK4 induced the production of both TNF-α and NO. Inhibitors of platelet-activating factor receptor (PAFR) blocked LTA- or Pam3CSK4-induced production of NO but not TNF-α. Jak2 tyrosine kinase blocked LTA-induced production of NO but not TNF-α. PAFR inhibition blocked phosphorylation of Jak2 and STAT1, a key factor for expressing inducible NO synthase. In addition, LTA did not induce IFN-β expression, and p38 mitogen-activated protein serine kinase was necessary for LTA-induced NO production but not for TNF-α production. These findings suggest that Gram-positive bacteria induce NO production using a PAFR signaling pathway to activate STAT1 via Jak2. This PAFR/Jak2/STAT1 signaling pathway resembles the IFN-β, type I IFNR/Jak/STAT1 pathway described for LPS. Consequently, Gram-positive and Gram-negative bacteria appear to have different but analogous mechanisms for NO production. PMID:16365452

  4. Downregulation of inducible nitric oxide synthase (iNOS) expression is implicated in the antiviral activity of acetylsalicylic acid in HCV-expressing cells.

    PubMed

    Ríos-Ibarra, Clara Patricia; Lozano-Sepulveda, Sonia; Muñoz-Espinosa, Linda; Rincón-Sánchez, Ana Rosa; Cordova-Fletes, Carlos; Rivas-Estilla, Ana María G

    2014-12-01

    Previously, we described that acetylsalicylic acid (ASA) decreases HCV expression, but the mechanisms involved have not been clearly established. We evaluated the participation of inducible nitric oxide synthase (iNOS) in the regulation of HCV-RNA induced by ASA. Huh7 cells expressing non-structural HCV proteins were exposed to 4 mM ASA and incubated at the same times we reported HCV downregulation (24-72 h), and iNOS mRNA and protein levels were then measured by real-time PCR and Western blot, respectively. Nitric oxide levels were measured at the same time. Inhibition of iNOS mRNA by small interfering RNAs (siRNA) and activation of the iNOS gene promoter by ASA treatment were evaluated. In Huh7 replicon cells treated with ASA, we found decreased levels of iNOS mRNA, iNOS protein and nitrosylated protein levels at 48-72 h. ASA exposure also reduced the transactivation of the iNOS promoter in HCV replicon cells at 48 h, and this was partly due to the decrease in the affinity of transcription factor C/EBP-β for its binding site in the iNOS promoter. siRNA silencing of iNOS decreased HCV-RNA expression (65 %) and potentiated the antiviral effect (80 %) of ASA compared with control cells. ASA reduces iNOS expression by downregulating promoter activity, mRNA and protein levels at the same time that it decreases HCV expression. These findings suggest that the antiviral activity of ASA is mediated partially through the modulation of iNOS.

  5. Extract from Ribes nigrum leaves in vitro activates nitric oxide synthase (eNOS) and increases CD39 expression in human endothelial cells.

    PubMed

    Luzak, Boguslawa; Boncler, Magdalena; Rywaniak, Joanna; Dudzinska, Dominika; Rozalski, Marek; Krajewska, Urszula; Balcerczak, Ewa; Podsedek, Anna; Redzynia, Malgorzata; Watala, Cezary

    2014-12-01

    The aim of the present study was to evaluate whether blackcurrant leaf extract (BLE) modulates endothelium antithrombotic function, namely increases the expression/activity of ADPase (CD39) and augments the production of nitric oxide in human umbilical vein endothelial cells (HUVEC). It was found that BLE with proanthocyanidins (60 % of the total polyphenol content) increased the CD39-positive endothelial cell fraction (up to 10 % for 2.5 μg/ml, and up to 33 % for 15 μg/ml, p < 0.05 or less) in a concentration-dependent manner, and enhanced endothelial nitric oxide synthase (eNOS) activation (T495 phosphorylation decreased by 31 ± 6 % for 2.5 μg/ml and 48 ± 6 % for 15 μg/ml; S1177 phosphorylation increased by 13 ± 3 % for 2.5 μg/ml and 18 ± 7 % for 15 μg/ml, compared to untreated cells, p < 0.05 or less). Additionally, incubation for 24 or 48 h with BLE at a lower range of polyphenol concentrations, significantly increased cell viability with a maximal effect at 2.5 μg/ml (viability increased by 24.8 ± 1.0 % for 24 h and by 32.5 ± 2.7 % for 48-h time incubation, p < 0.0001). The increased CD39 expression and the increased eNOS activation in HUVEC can be regarded as the beneficial markers of the improvement of antiplatelet action of endothelial cells. Unexpectedly, these assumptions were not confirmed in the experimental model of platelet-endothelial cell interactions. These observations lead to the conclusion that BLE may improve endothelial cell viability at low physiological concentrations without affecting the antiplatelet action of endothelium. PMID:25407137

  6. Novel role of the nitrite transporter NirC in Salmonella pathogenesis: SPI2-dependent suppression of inducible nitric oxide synthase in activated macrophages.

    PubMed

    Das, Priyanka; Lahiri, Amit; Lahiri, Ayan; Chakravortty, Dipshikha

    2009-08-01

    Activation of macrophages by interferon gamma (IFN-gamma) and the subsequent production of nitric oxide (NO) are critical for the host defence against Salmonella enterica serovar Typhimurium infection. We report here the inhibition of IFN-gamma-induced NO production in RAW264.7 macrophages infected with wild-type Salmonella. This phenomenon was shown to be dependent on the nirC gene, which encodes a potential nitrite transporter. We observed a higher NO output from IFN-gamma-treated macrophages infected with a nirC mutant of Salmonella. The nirC mutant also showed significantly decreased intracellular proliferation in a NO-dependent manner in activated RAW264.7 macrophages and in liver, spleen and secondary lymph nodes of mice, which was restored by complementing the gene in trans. Under acidified nitrite stress, a twofold more pronounced NO-mediated repression of SPI2 was observed in the nirC knockout strain compared to the wild-type. This enhanced SPI2 repression in the nirC knockout led to a higher level of STAT-1 phosphorylation and inducible nitric oxide synthase (iNOS) expression than seen with the wild-type strain. In iNOS knockout mice, the organ load of the nirC knockout strain was similar to that of the wild-type strain, indicating that the mutant is exclusively sensitive to the host nitrosative stress. Taken together, these results reveal that intracellular Salmonella evade killing in activated macrophages by downregulating IFN-gamma-induced NO production, and they highlight the critical role of nirC as a virulence gene.

  7. Methanolic Extract of Clinacanthus nutans Exerts Antinociceptive Activity via the Opioid/Nitric Oxide-Mediated, but cGMP-Independent, Pathways

    PubMed Central

    Abdul Rahim, Mohammad Hafiz; Zakaria, Zainul Amiruddin; Mohd Sani, Mohd Hijaz; Omar, Maizatul Hasyima; Yakob, Yusnita; Cheema, Manraj Singh; Ching, Siew Mooi; Ahmad, Zuraini; Abdul Kadir, Arifah

    2016-01-01

    The objectives of the present study were to determine the mechanisms of antinociceptive effect of methanol extract of Clinacanthus nutans (Acanthaceae) leaves (MECN) using various animal nociceptive models. The antinociceptive activity of orally administered 10% DMSO, 100 mg/kg acetylsalicylic acid (ASA), 5 mg/kg morphine, or MECN (100, 250, and 500 mg/kg) was determined using the acetic acid-induced abdominal constriction (ACT), formalin-induced paw licking (FT), and hot plate tests (HPT). The role of opioid and nitric oxide/cyclic guanosine monophosphate (NO/cGMP) systems was also investigated. The results showed that MECN produced a significant (p < 0.05) antinociceptive response in all nociceptive models with the recorded ED50 value of 279.3 mg/kg for the ACT, while, for the early and late phases of the FT, the value was >500 mg/kg or 227.7 mg/kg, respectively. This antinociceptive activity was fully antagonized by naloxone (a nonselective opioid antagonist) but was partially reversed by l-arginine (l-arg; a nitric oxide [NO] precursor), Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME; an NO synthase inhibitor), or their combinations thereof. In contrast, 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (ODQ; a soluble guanylyl cyclase inhibitor) enhanced the extract's antinociception. UHPLC analysis revealed the presence of several flavonoid-based compounds with antinociceptive action. In conclusion, MECN exerted the peripherally and centrally mediated antinociceptive activity via the modulation of the opioid/NO-mediated, but cGMP-independent, systems. PMID:27190528

  8. ENDOTHELIAL NITRIC OXIDE (NO) AND ITS PATHOPHYSIOLOGIC REGULATION

    PubMed Central

    Chatterjee, A.; Catravas, J.D.

    2008-01-01

    Nitric oxide (NO) is a gaseous lipophilic free radical generated by three distinct isoforms of nitric oxide synthases (NOS), type 1 or neuronal (nNOS), type 2 or inducible (iNOS) and type 3 or endothelial NOS (eNOS). Expression of eNOS is altered in many types of cardiovascular disease, such as atherosclerosis, diabetes and hypertension. The ubiquitous chaperone heat shock protein 90 (hsp90) associates with NOS and is important for its proper folding and function. Current studies point toward a therapeutic potential by modulating hsp90-NOS association in various vascular diseases. Here we review the transcriptional regulation of endothelial NOS and factors affecting eNOS activity and function, as well as the important vascular pathologies associated with altered NOS function, focusing on the regulatory role of hsp90 and other factors in NO-associated pathogenesis of these diseases. PMID:18692595

  9. Solubilization and Resolution of the Membrane-Bound Nitrite Reductase from Paracoccus Halodenitrificans into Nitrite and Nitric Oxide Reductases

    NASA Technical Reports Server (NTRS)

    Grant, Michael A.; Cronin, Sonja E.; Hochstein, Lawrence I.

    1984-01-01

    Membranes prepared from Paracoccus halodenitrificans reduced nitrite or nitric oxide to nitrous oxide. Extraction of these membranes with the detergent CHAPSO [3-(3-Chlolamidoporopyldimethylammonio)-1-(2- hydroxy-1-propanesulfonate)], followed by ammonium sulfate fractionation of the solubilized proteins, resulted in the separation of nitrite and nitric oxide reductase activities. The fraction containing nitrite reductase activity spectrally resembled a cd-type cytochrome. Several cytochromes were detected in the nitric oxide reductase fraction. Which, if any, of these cytochromes is associated with the reduction of nitric oxide is not clear at this time.

  10. Nitric oxide synthesis in locust olfactory interneurones

    PubMed

    Elphick; Rayne; Riveros-Moreno; Moncada; Shea

    1995-01-01

    The brain of the locust Schistocerca gregaria contains a nitric oxide synthase (NOS) that has similar properties to mammalian neuronal NOS. It catalyses the production of equimolar quantities of nitric oxide (NO) and citrulline from l-arginine in a Ca2+/calmodulin- and NADPH-dependent manner and is inhibited by the Nomega-nitro and Nomega-monomethyl analogues of l-arginine. In Western blots, an antiserum to the 160 kDa rat cerebellar NOS subunit recognises a locust brain protein with a molecular mass of approximately 135 kDa. NOS is located in several parts of the locust brain, including the mushroom bodies, but it is particularly abundant in the olfactory processing centres, the antennal lobes. Here it is present in two groups of local interneurones (a pair and a cluster of about 50) that project into the neuropile of the antennal lobes. The processes of these neurones terminate in numerous glomerulus-like structures where the synapses between primary olfactory receptor neurones and central interneurones are formed. NOS-containing local interneurones have also been identified in the mammalian olfactory bulb, suggesting that NO performs analogous functions in locust and mammalian olfactory systems. As yet, nothing is known about the role of NO in olfaction, but it seems likely that it is involved in the processing of chemosensory input to the brain. The locust antennal lobe may be an ideal 'simple' system in which this aspect of NO function can be examined.

  11. Nitric oxide-releasing NSAIDs: a novel class of GI-sparing anti-inflammatory drugs.

    PubMed

    Wallace, J L; Pittman, Q J; Cirino, G

    1995-01-01

    The addition of a nitric oxide-releasing moiety to a number of common nonsteroidal anti-inflammatory drugs markedly reduces their toxicity in the gastrointestinal tract without interfering with their ability to inhibit prostaglandin synthesis. Moreover, the anti-inflammatory and anti-pyretic activities of the nitric-oxide releasing NSAID were comparable to the parent compound, while the anti-thrombotic activity in vivo was significantly enhanced. Nitric oxide-releasing NSAIDs may represent an alternative to existing anti-inflammatory, anti-pyretic and anti-thrombotic agents with greatly reduced toxicity in the gastrointestinal tract. PMID:7610982

  12. HMG-CoA Reductase Inhibitor Improves Endothelial Dysfunction in Spontaneous Hypertensive Rats Via Down-regulation of Caveolin-1 and Activation of Endothelial Nitric Oxide Synthase

    PubMed Central

    Suh, Jung-Won; Chang, Hyuk-Jae; Cho, Young-Seok; Youn, Tae-Jin; Chae, In-Ho; Kim, Kwang-Il; Kim, Cheol-Ho; Kim, Hyo-soo; Oh, Buyng-Hee; Park, Young-Bae

    2010-01-01

    Hypertension is associated with endothelial dysfunction and increased cardiovascular risk. Caveolin-1 regulates nitric oxide (NO) signaling by modulating endothelial nitric oxide synthase (eNOS). The purpose of this study was to examine whether HMG-CoA reductase inhibitor improves impaired endothelial function of the aorta in spontaneous hypertensive rat (SHR) and to determine the underlying mechanisms involved. Eight-week-old male SHR were assigned to either a control group (CON, n=11) or a rosuvastatin group (ROS, n=12), rosuvastatin (10 mg/kg/day) administered for eight weeks. Abdominal aortic rings were prepared and responses to acetylcholine (10-9-10-4 M) were determined in vitro. To evaluate the potential role of NO and caveolin-1, we examined the plasma activity of NOx, eNOS, phosphorylated-eNOS and expression of caveolin-1. The relaxation in response to acetylcholine was significantly enhanced in ROS compared to CON. Expression of eNOS RNA was unchanged, whereas NOx level and phosphorylated-eNOS at serine-1177 was increased accompanied with depressed level of caveolin-1 in ROS. We conclude that 3-Hydroxy-3-methylglutaryl Coenzyme-A (HMG-CoA) reductase inhibitor can improve impaired endothelial dysfunction in SHR, and its underlying mechanisms are associated with increased NO production. Furthermore, HMG-CoA reductase inhibitor can activate the eNOS by phosphorylation related to decreased caveolin-1 abundance. These results imply the therapeutic strategies for the high blood pressure-associated endothelial dysfunction through modifying caveolin status. PMID:20052342

  13. Leptin protection of salivary gland acinar cells against ethanol cytotoxicity involves Src kinase-mediated parallel activation of prostaglandin and constitutive nitric oxide synthase pathways.

    PubMed

    Slomiany, B L; Slomiany, A

    2008-04-01

    Leptin, a pleiotropic cytokine secreted by adipocytes but also identified in salivary glands and saliva, is recognized as an important element of oral mucosal defense. Here, we report that in sublingual salivary glands leptin protects the acinar cells of against ethanol cytotoxicity. We show that ethanol- induced cytotoxicity, characterized by a marked drop in the acinar cell capacity for NO production, arachidonic acid release and prostaglandin generation, was subject to suppression by leptin. The loss in countering capacity of leptin on the ethanol-induced cytotoxicity was attained with cyclooxygenase inhibitor, indomethacin and nitric oxide synthase (cNOS) inhibitor, L-NAME, as well as PP2, an inhibitor of Src kinase. Indomethacin, while not affecting leptin-induced arachidonic acid release, caused the inhibition in PGE2 generation, pretreatment with L-NAME led to the inhibition in NO production, whereas PP2 exerted the inhibitory effect on leptin-induced changes in NO, arachidonic acid, and PGE2. The leptin-induced changes in arachidonic acid release and PGE2 generation were blocked by ERK inhibitor, PD98059, but not by PI3K inhibitor, wortmannin. Further, leptin suppression of ethanol cytotoxicity was reflected in the increased Akt and cNOS phosphorylation that was sensitive to PP2. Moreover, the stimulatory effect of leptin on the acinar cell cNOS activity was inhibited not only by PP2, but also by Akt inhibitor, SH-5, while wortmannin had no effect. Our findings demonstrate that leptin protection of salivary gland acinar cells against ethanol cytotoxicity involves Src kinase-mediated parallel activation of MAPK/ERK and Akt that result in up-regulation of the respective prostaglandin and nitric oxide synthase pathways.

  14. Nitric oxide synthase and NADPH-diaphorase after acute hypobaric hypoxia in the rat caudate putamen.

    PubMed

    Encinas, Juan Manuel; Fernández, Ana Patricia; Salas, Eduardo; Castro-Blanco, Susana; Muñoz, Priscila; Rodrigo, José; Serrano, Julia

    2004-03-01

    Changes in the production system of nitric oxide (NO), a multifunctional biological messenger known to participate in blood-flow regulation, neuromodulation, and neuroprotection or neurotoxicity, were investigated in the caudate putamen of adult rats submitted to hypobaric hypoxia. Employing immunohistochemistry, Western blotting, enzymatic assay, and NADPH-diaphorase staining, we demonstrate that neuronal nitric oxide synthase (nNOS) expression and constitutive nitric oxide synthase (cNOS) activity were transiently activated by 7 h of exposure to a simulated altitude of 8325 m (27,000 ft). In addition, endothelial nitric oxide synthase (eNOS) immunoreactivity and blood vessel NADPH-diaphorase staining peaked immediately after the hypoxic stimulus, whereas inducible nitric oxide synthase (iNOS) expression and activity remained unaltered. Nitrotyrosine formation, a marker of protein nitration, was evaluated by immunohistochemistry and Western blotting, and was found to increase parallel to nitric oxide synthesis. We conclude that the nitric oxide system undergoes significant transient alterations in the caudate putamen of adult rats submitted to acute hypobaric hypoxia.

  15. Enhanced Nitric Oxide Synthase Activation via Protease-Activated Receptor 2 Is Involved in the Preserved Vasodilation in Aortas from Metabolic Syndrome Rats.

    PubMed

    Maruyama, Kana; Kagota, Satomi; McGuire, John J; Wakuda, Hirokazu; Yoshikawa, Noriko; Nakamura, Kazuki; Shinozuka, Kazumasa

    2015-01-01

    Endothelium-dependent vasodilation via protease-activated receptor 2 (PAR2) is preserved in mesenteric arteries from SHRSP.Z-Leprfa/IzmDmcr rats (SHRSP.ZF) with metabolic syndrome even though nitric oxide (NO)-mediated vasodilation is attenuated. Therefore, we examined the PAR2 mechanisms underlying metabolic syndrome-resistant vasodilation in SHRSP.ZF aortas with ageing. In isolated aortas, the PAR2 agonist 2-furoyl-LIGRLO-amide (2fly) caused vasodilation that was sustained in male SHRSP.ZF until 18 weeks of age, but was attenuated afterwards compared with age-matched Wistar-Kyoto rats (controls) at 23 weeks. In contrast, acetylcholine-induced vasodilation was impaired in SHRSP.ZF already at 18 weeks of age. Treatments of aortas with inhibitors of NO synthase and soluble guanylate cyclase abolished the sustained 2fly- and residual acetylcholine-induced vasodilation in SHRSP.ZF at 18 weeks of age. In the aortas of SHRSP.ZF, 8-bromo-cGMP-induced vasodilation, NO production and cGMP accumulation elicited by 2fly were not different from in the controls. PAR2 agonist increased phospho-Ser1177-eNOS protein content only in SHRSP.ZF aortas. These results indicate that vasodilation mediated by PAR2 is sustained even though NO-dependent relaxation is attenuated with ageing/exposure to metabolic disorders in large-caliber arteries from SHRSP.ZF. PAR2 stimulation of NO production via an additional pathway that targets phosphorylation of Ser1177-eNOS suggests a regulatory mechanism for sustaining agonist-mediated vasodilation in metabolic syndrome.

  16. Polygonum viviparum L. induces vasorelaxation in the rat thoracic aorta via activation of nitric oxide synthase in endothelial cells

    PubMed Central

    2014-01-01

    Background In the past several decades, Polygonum viviparum L. (PV) was reported to have antibacterial, antiulcer, antioxidant, antitumor, anti-inflammatory, and antiarthritic properties. The anti-inflammatory pathway was recently elucidated through cytosolic nuclear factor E2-related factor 2 (Nrf2) activation and heme oxygenase (HO)-1 protein expression. PV is a perennial herb and widely distributed in high-elevation mountain regions, such as the Tibetan Plateau. In Tibetan traditional medicine, PV is usually used to boost the blood circulation to dissipate blood stasis. Therefore, this study focused on how PV improves the vascular circulation and acts on vascular tissues. Methods In this study, we isolated aortas from Sprague-Dawley rats (male, weight about 250 ~ 350 g), and detected the effects of PV on phenylephrine (PE)-induced contraction and cyclic guanosine 3′,5′-monophosphate (cGMP) formation using aortic rings. In addition, human umbilical vein endothelial cells (HUVECs) were used to exam nitric oxygen (NO) synthase (NOS) activity by directly measuring NO production in the culture medium. Endothelial (e) NOS phosphorylation, and cytosolic Nrf2 and HO-1 expressions were measured using a Western blot analysis. Results PV dose-dependently relaxed PE-induced contractions in endothelial-intact but not -denuded aorta. The concentration to produce 50% relaxation was 22.04 ± 1.77 μg/ml. PV-induced vasorelaxation was markedly blocked by pretreatment with NG-nitro-L-arginine methyl ester (L-NAME), an NOS inhibitor, methylene blue (MB), a guanylyl cyclase inhibitor, and hemoglobin, an NO scavenger. PV increased cGMP formation; however, this effect was also suppressed by co-pretreatment with l-NAME, MB, hemoglobin, and Ca2+-free medium. In HUVECs, PV increased NO formation, which was greatly attenuated by NOS inhibitors (L-NAME and L-NMMA) and by removing extracellular Ca2+ and chelating intracellular Ca2+ with BAPTA-AM. In addition, PV promoted e

  17. Nitric Oxide--Some Old and New Perspectives.

    ERIC Educational Resources Information Center

    Ainscough, Eric W.; Brodie, Andrew M.

    1995-01-01

    Because of the role it plays in physiology and neurobiology, there is a rebirth of interest in nitric oxide. It can affect enzyme and immune system regulation and cytotoxicity. Nitric oxide may represent a new class of signaling molecules--gases that pass through cells and vanish. Overactive neurons produce large amounts of NO which may be linked…

  18. 21 CFR 868.2380 - Nitric oxide analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nitric oxide analyzer. 868.2380 Section 868.2380 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2380 Nitric oxide analyzer....

  19. 21 CFR 868.5165 - Nitric oxide administration apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nitric oxide administration apparatus. 868.5165 Section 868.5165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5165 Nitric oxide...

  20. 21 CFR 868.5165 - Nitric oxide administration apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nitric oxide administration apparatus. 868.5165 Section 868.5165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5165 Nitric oxide...

  1. 21 CFR 868.2380 - Nitric oxide analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nitric oxide analyzer. 868.2380 Section 868.2380 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2380 Nitric oxide analyzer....

  2. 21 CFR 868.2380 - Nitric oxide analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nitric oxide analyzer. 868.2380 Section 868.2380 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2380 Nitric oxide analyzer....

  3. 21 CFR 868.2380 - Nitric oxide analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nitric oxide analyzer. 868.2380 Section 868.2380 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2380 Nitric oxide analyzer....

  4. 21 CFR 868.5165 - Nitric oxide administration apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nitric oxide administration apparatus. 868.5165 Section 868.5165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5165 Nitric oxide...

  5. 21 CFR 868.2380 - Nitric oxide analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nitric oxide analyzer. 868.2380 Section 868.2380 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2380 Nitric oxide analyzer....

  6. 21 CFR 868.5165 - Nitric oxide administration apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nitric oxide administration apparatus. 868.5165 Section 868.5165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5165 Nitric oxide...

  7. 21 CFR 868.5165 - Nitric oxide administration apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nitric oxide administration apparatus. 868.5165 Section 868.5165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5165 Nitric oxide...

  8. Neuroprotective effect of Chuk-Me-Sun-Dan on NMDA- and AMPA-evoked nitric oxide synthase activity in mouse brain.

    PubMed

    Koo, Byung-Soo; Choi, Eun-Gyu; Park, Jae-Bok; Cho, Chang-Ho; Chung, Kang-Hyun; Kim, Cheorl-Ho

    2005-01-01

    Chukmesundan (CMSD) is composed of 8 medicinal herbs including Panex ginseng C.A. MEYER, Atractylodes macrocephala KOID, Poria cocos WOLF, Pinellia ternata BREIT, Brassica alba BOISS, Aconitum carmichaeli DEBX, Cynanchum atratum BGE, and Cuscuta chinensis LAM and used for the treatment of various symptoms accompanying hypertension and cerebrovascular disorders. This study was carried out to examine the effects of CMSD on N-methyl-D-aspartate (NMDA)-evoked, and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-evoked nitric oxide synthase (NOS) activity in mouse brain. In adult forebrain, CMSD influences neuronal maintenance and is neuroprotective in several injury models through mechanisms that are incompletely understood. Interaction is observed between CMSD and nitric oxide (NO). Because NO affects both neural plasticity and degeneration, we hypothesized that CMSD might rapidly modulate NO production. Using in vivo microdialysis we measured conversion of L-[14C] arginine to L-[14C] citrulline as an accurate reflection of NOS activity in adult mouse hippocampus. CMSD significantly reduced NOS activities to 62% of basal levels within 2 days of onset of delivery and maintained NOS activity at less than 45% of baseline throughout 3 days of delivery. These effects did not occur with control (distilled water) and were not mediated by effect of CMSD on glutamate levels. In addition, simultaneous delivery of CMSD treatment prevented significant increases in NOS activity triggered by the glutamate receptor agonists NMDA and AMPA. Rapid suppression by CMSD of basal and glutamate-stimulated NOS activity may regulate neuromodulatory functions of NO or protect neurons from NO toxicity and suggests a novel mechanism for rapidly mediating functions of CMSD. It is shown that NMDA receptor stimulation leads to activation of p21ras (Ras) through generation of NO via neuronal NOS. The competitive NOS inhibitor, L-nitroarginine methyl ester, and CMSD prevents Ras

  9. Nitric oxide and septic shock. From bench to bedside.

    PubMed Central

    Kuhl, S J; Rosen, H

    1998-01-01

    Refractory hypotension with end-organ hypoperfusion is an ominous feature of inflammatory shock. In the past fifteen years, nitric oxide (a diffusible, short-lived product of arginine metabolism) has been found to be an important regulatory molecule in several areas of metabolism, including vascular tone control. Vascular endothelial cells constitutively produce low levels of nitric oxide that regulate blood pressure by mediating adjacent smooth-muscle relaxation. In an inflammatory shock state, cytokines, like interleukin-1 and tumor necrosis factor-alpha, induce a separate, high-output form of the enzyme that synthesizes nitric oxide in both endothelial and smooth-muscle cells. The ensuing high rates of nitric oxide formation result in extensive smooth-muscle relaxation, pressor refractory vasodilation, and--ultimately--shock. The concept of the pathogenesis of inflammatory shock explains many limitations of current therapies and may foster the development of new interventions to mitigate the effects of nitric oxide overproduction in this syndrome. PMID:9549416

  10. Nitric Oxide Modulators: An Emerging Class of Medicinal Agents

    PubMed Central

    Deshpande, S. R.; Satyanarayana, K.; Rao, M. N. A.; Pai, K. V.

    2012-01-01

    Nitric oxide, a unique messenger in biological system, is ubiquitously present virtually in all tissues revealing its versatile nature of being involved in diverse physiological functions such as vascular tone, inhibition of platelet aggregation, cell adhesion, neurotransmission and enzyme and immune regulation. The tremendous advancements made in the past few decades in this area suggests that the nitric oxide modulation either by its exogenous release through nitric oxide donors or inhibition of its synthesis by nitric oxide synthase inhibitors in physiological milieu may provide newer clinical strategies for the treatment of some diseases. In this review, an attempt is made to document and understand the biological chemistry of different classes of nitric oxide modulators that would prove to be a fruitful area in the years to come. PMID:23798773

  11. Nitric oxide protects endothelium from cadmium mediated leakiness.

    PubMed

    Nagarajan, Shunmugam; Rajendran, Saranya; Saran, Uttara; Priya, M Krishna; Swaminathan, Akila; Siamwala, Jamila H; Sinha, Swaraj; Veeriah, Vimal; Sonar, Punam; Jadhav, Vivek; Jaffar Ali, B M; Chatterjee, Suvro

    2013-05-01

    Cadmium targets the vascular endothelium causing endothelial dysfunction and leakiness of endothelial barrier. Nitric oxide plays a major role in mediating endothelial functions including angiogenesis, migration and permeability. The present study investigates the nitric oxide effects on cadmium induced endothelial leakiness. Results of ex vivo and in vitro permeability assays showed that even a sub-lethal dose of cadmium chloride (1 µM) was sufficient to induce leakiness of endothelial cells. Cadmium drastically altered the actin polymerisation pattern and membrane tension of these cells compared to controls. Addition of nitric oxide donor Spermine NONOate (SP) significantly blunted cadmium-mediated effects and recover endothelial cells integrity. Cadmium-induced cytoskeletal rearrangements and membrane leakiness are associated with the low nitric oxide availability and high reactive oxygen species generation. In brief, we show the protective role of nitric oxide against cadmium-mediated endothelial leakiness.

  12. Nitric oxide and the cardiovascular system.

    PubMed

    Bohlen, Harold Glenn

    2015-04-01

    Nitric oxide (NO) generated by endothelial cells to relax vascular smooth muscle is one of the most intensely studied molecules in the past 25 years. Much of what is known about NO regulation of NO is based on blockade of its generation and analysis of changes in vascular regulation. This approach has been useful to demonstrate the importance of NO in large scale forms of regulation but provides less information on the nuances of NO regulation. However, there is a growing body of studies on multiple types of in vivo measurement of NO in normal and pathological conditions. This discussion will focus on in vivo studies and how they are reshaping the understanding of NO's role in vascular resistance regulation and the pathologies of hypertension and diabetes mellitus. The role of microelectrode measurements in the measurement of [NO] will be considered because much of the controversy about what NO does and at what concentration depends upon the measurement methodology. For those studies where the technology has been tested and found to be well founded, the concept evolving is that the stresses imposed on the vasculature in the form of flow-mediated stimulation, chemicals within the tissue, and oxygen tension can cause rapid and large changes in the NO concentration to affect vascular regulation. All these functions are compromised in both animal and human forms of hypertension and diabetes mellitus due to altered regulation of endothelial cells and formation of oxidants that both damage endothelial cells and change the regulation of endothelial nitric oxide synthase. PMID:25880514

  13. Inhaled nitric oxide alters the distribution of blood flow in the healthy human lung, suggesting active hypoxic pulmonary vasoconstriction in normoxia

    PubMed Central

    Asadi, Amran K.; Sá, Rui Carlos; Kim, Nick H.; Theilmann, Rebecca J.; Hopkins, Susan R.; Buxton, Richard B.

    2014-01-01

    Hypoxic pulmonary vasoconstriction (HPV) is thought to actively regulate ventilation-perfusion (V̇a/Q̇) matching, reducing perfusion in regions of alveolar hypoxia. We assessed the extent of HPV in the healthy human lung using inhaled nitric oxide (iNO) under inspired oxygen fractions (FiO2) of 0.125, 0.21, and 0.30 (a hyperoxic stimulus designed to abolish HPV without the development of atelectasis). Dynamic measures of blood flow were made in a single sagittal slice of the right lung of five healthy male subjects using an arterial spin labeling (ASL) MRI sequence, following a block stimulus pattern (3 × 60 breaths) with 40 ppm iNO administered in the central block. The overall spatial heterogeneity, spatiotemporal variability, and regional pattern of pulmonary blood flow was quantified as a function of condition (FiO2 × iNO state). While spatial heterogeneity did not change significantly with iNO administration or FiO2, there were statistically significant increases in Global Fluctuation Dispersion, (a marker of spatiotemporal flow variability) when iNO was administered during hypoxia (5.4 percentage point increase, P = 0.003). iNO had an effect on regional blood flow that was FiO2 dependent (P = 0.02), with regional changes in the pattern of blood flow occurring in hypoxia (P = 0.007) and normoxia (P = 0.008) tending to increase flow to dependent lung at the expense of nondependent lung. These findings indicate that inhaled nitric oxide significantly alters the distribution of blood flow in both hypoxic and normoxic healthy subjects, and suggests that some baseline HPV may indeed be present in the normoxic lung. PMID:25429099

  14. Effect of simulated microgravity and centrifugation on nitric oxide synthase activity of osteocyte-like cell line MLO-Y4

    NASA Astrophysics Data System (ADS)

    Sun, Lian-Wen; Yang, Xiao; Fan, Yu-Bo

    Bone is a highly mechanosensitive tissue, which can adapt functionally to varying levels of mechanical loads throughout a lifetime. Osteocytes are thought to be the most mechanically sensitive bone cell population. In order to understand the mechanism of microgravity-induced bone loss, it's very important to research the behavior of osteocytes under microgravity. In this study, rotary cell culture system was used to simulate microgravity. Nitric oxide synthase (NOS) activity in osteocyte-like cell MLO-Y4 was investigated under simulated microgravity. And the effect of centrifugation on NOS activity in sedentary and rotary culture cell was also investi-gated. The cultured cells were divided into four groups, including sedentary control (CON), sedentary control and centrifugation (CONC), rotary culture (RT), rotary and centrifugation (RTC). In CONC and RTC, NOS activity was determined after centrifugation (1100g 5min). The results showed NOS activity decreased significantly in RT compared with CON. However, this difference disappeared after centrifugation. On the other hand, NOS activity increased significant in RTC compared with RT while there was no difference between CON and CONC. These results indicate the normal centrifugation could counter the effect of simulated micro-gravity on NOS activity. However, it has no effect on the cells cultured under 1G. In general, osteocytes under simulated microgravity are more sensitive to centrifugation than that under 1G.

  15. Plant pathogenic Streptomyces species produce nitric oxide synthase-derived nitric oxide in response to host signals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitric oxide (NO) is a potent intercellular signal for defense, development and metabolism in animals and plants. In mammals, highly regulated nitric oxide synthases (NOSs) generate NO. NOS homologs exist in some prokaryotes, but direct evidence for NO production by these proteins has been lacking...

  16. Nitric Oxide in Astrocyte-Neuron Signaling

    SciTech Connect

    Nianzhen Li

    2002-06-27

    Astrocytes, a subtype of glial cell, have recently been shown to exhibit Ca{sup 2+} elevations in response to neurotransmitters. A Ca{sup 2+} elevation can propagate to adjacent astrocytes as a Ca{sup 2+} wave, which allows an astrocyte to communicate with its neighbors. Additionally, glutamate can be released from astrocytes via a Ca{sup 2+}-dependent mechanism, thus modulating neuronal activity and synaptic transmission. In this dissertation, the author investigated the roles of another endogenous signal, nitric oxide (NO), in astrocyte-neuron signaling. First the author tested if NO is generated during astrocytic Ca{sup 2+} signaling by imaging NO in purified murine cortical astrocyte cultures. Physiological concentrations of a natural messenger, ATP, caused a Ca{sup 2+}-dependent NO production. To test the roles of NO in astrocytic Ca{sup 2+} signaling, the author applied NO to astrocyte cultures via addition of a NO donor, S-nitrosol-N-acetylpenicillamine (SNAP). NO induced an influx of external Ca{sup 2+}, possibly through store-operated Ca{sup 2+} channels. The NO-induced Ca{sup 2+} signaling is cGMP-independent since 8-Br-cGMP, an agonistic analog of cGMP, did not induce a detectable Ca{sup 2+} change. The consequence of this NO-induced Ca{sup 2+} influx was assessed by simultaneously monitoring of cytosolic and internal store Ca{sup 2+} using fluorescent Ca{sup 2+} indicators x-rhod-1 and mag-fluo-4. Blockage of NO signaling with the NO scavenger PTIO significantly reduced the refilling percentage of internal stores following ATP-induced Ca{sup 2+} release, suggesting that NO modulates internal store refilling. Furthermore, locally photo-release of NO to a single astrocyte led to a Ca{sup 2+} elevation in the stimulated astrocyte and a subsequent Ca{sup 2+} wave to neighbors. Finally, the author tested the role of NO inglutamate-mediated astrocyte-neuron signaling by recording the astrocyte-evoked glutamate-dependent neuronal slow inward current (SIC

  17. Nitric Oxide Release Part I. Macromolecular Scaffolds

    PubMed Central

    Riccio, Daniel A.; Schoenfisch, Mark H.

    2012-01-01

    Summary The roles of nitric oxide (NO) in physiology and pathophysiology merit the use of NO as a therapeutic for certain biomedical applications. Unfortunately, limited NO payloads, too rapid NO release, and the lack of targeted NO delivery have hindered the clinical utility of NO gas and low molecular weight NO donor compounds. A wide-variety of NO-releasing macromolecular scaffolds has thus been developed to improve NO’s pharmacological potential. In this tutorial review, we provide an overview of the most promising NO release scaffolds including protein, organic, inorganic, and hybrid organic-inorganic systems. The NO release vehicles selected for discussion were chosen based on their enhanced NO storage, tunable NO release characteristics, and potential as therapeutics. PMID:22362355

  18. Nitric Oxide Release Part II. Therapeutic Applications

    PubMed Central

    Carpenter, Alexis W.; Schoenfisch, Mark H.

    2012-01-01

    Summary A wide range of nitric oxide (NO)-releasing materials have emerged as potential therapeutics that exploit NO’s vast biological roles. Macromolecular NO-releasing scaffolds are particularly promising due to their ability to store and deliver larger NO payloads in a more controlled and effective manner compared to low molecular weight NO donors. While a variety of scaffolds (e.g., particles, dendrimers, and polymers/films) have been cleverly designed, the ultimate clinical utility of most NO-releasing macromolecules remains unrealized. Although not wholly predictive of clinical success, in vitro and in vivo investigations have enabled a preliminary evaluation of the therapeutic potential of such materials. Herein, we review the application of macromolecular NO therapies for cardiovascular disease, cancer, bacterial infections, and wound healing. PMID:22362384

  19. Nitric Oxide Signaling in the Microcirculation

    PubMed Central

    Buerk, Donald G.; Barbee, Kenneth A.; Jaron, Dov

    2013-01-01

    Several apparent paradoxes are evident when one compares mathematical predictions from models of nitric oxide (NO) diffusion and convection in vasculature structures with experimental measurements of NO (or related metabolites) in animal and human studies. Values for NO predicted from mathematical models are generally much lower than in vivo NO values reported in the literature for experiments, specifically with NO microelectrodes positioned at perivascular locations next to different sizes of blood vessels in the microcirculation and NO electrodes inserted into a wide range of tissues supplied by the microcirculation of each specific organ system under investigation. There continues to be uncertainty about the roles of NO scavenging by hemoglobin versus a storage function that may conserve NO, and other signaling targets for NO need to be considered. This review describes model predictions and relevant experimental data with respect to several signaling pathways in the microcirculation that involve NO. PMID:22196161

  20. Nitric oxide and plant iron homeostasis.

    PubMed

    Buet, Agustina; Simontacchi, Marcela

    2015-03-01

    Like all living organisms, plants demand iron (Fe) for important biochemical and metabolic processes. Internal imbalances, as a consequence of insufficient or excess Fe in the environment, lead to growth restriction and affect crop yield. Knowledge of signals and factors affecting each step in Fe uptake from the soil and distribution (long-distance transport, remobilization from old to young leaves, and storage in seeds) is necessary to improve our understanding of plant mineral nutrition. In this context, the role of nitric oxide (NO) is discussed as a key player in maintaining Fe homeostasis through its cross talk with hormones, ferritin, and frataxin and the ability to form nitrosyl-iron complexes. PMID:25612116

  1. The emerging multifaceted roles of nitric oxide.

    PubMed Central

    Kuo, P C; Schroeder, R A

    1995-01-01

    Nitric oxide (NO) is a highly reactive free radical with a multitude of organ specific regulatory functions. Since 1985, NO has been the subject of numerous research efforts and as a result, has been found to play a major role in the cardiovascular, pulmonary, gastrointestinal, immune, and central nervous systems. In addition, deranged NO synthesis is the basis for a number of pathophysiologic states, such as atherosclerosis, pulmonary hypertension, pyloric stenosis, and the hypertension associated with renal failure. Traditional NO donors such as sodium nitroprusside and new pharmacologic NO adducts such as S-nitrosothiols may serve as exogenous sources of NO for the treatment of NO-deficient pathologic states. This review is an attempt to acquaint the surgical community with the fundamentals of NO biochemistry and physiology. Increased knowledge of its functions in normal homeostasis and pathologic states will enable physicians to better understand these disease processes and utilize new pharmacologic therapies. PMID:7717775

  2. Nitric oxide-releasing porous silicon nanoparticles.

    PubMed

    Kafshgari, Morteza Hasanzadeh; Cavallaro, Alex; Delalat, Bahman; Harding, Frances J; McInnes, Steven Jp; Mäkilä, Ermei; Salonen, Jarno; Vasilev, Krasimir; Voelcker, Nicolas H

    2014-01-01

    In this study, the ability of porous silicon nanoparticles (PSi NPs) to entrap and deliver nitric oxide (NO) as an effective antibacterial agent is tested against different Gram-positive and Gram-negative bacteria. NO was entrapped inside PSi NPs functionalized by means of the thermal hydrocarbonization (THC) process. Subsequent reduction of nitrite in the presence of d-glucose led to the production of large NO payloads without reducing the biocompatibility of the PSi NPs with mammalian cells. The resulting PSi NPs demonstrated sustained release of NO and showed remarkable antibacterial efficiency and anti-biofilm-forming properties. These results will set the stage to develop antimicrobial nanoparticle formulations for applications in chronic wound treatment.

  3. Nitric oxide-releasing porous silicon nanoparticles

    NASA Astrophysics Data System (ADS)

    Kafshgari, Morteza Hasanzadeh; Cavallaro, Alex; Delalat, Bahman; Harding, Frances J.; McInnes, Steven JP; Mäkilä, Ermei; Salonen, Jarno; Vasilev, Krasimir; Voelcker, Nicolas H.

    2014-07-01

    In this study, the ability of porous silicon nanoparticles (PSi NPs) to entrap and deliver nitric oxide (NO) as an effective antibacterial agent is tested against different Gram-positive and Gram-negative bacteria. NO was entrapped inside PSi NPs functionalized by means of the thermal hydrocarbonization (THC) process. Subsequent reduction of nitrite in the presence of d-glucose led to the production of large NO payloads without reducing the biocompatibility of the PSi NPs with mammalian cells. The resulting PSi NPs demonstrated sustained release of NO and showed remarkable antibacterial efficiency and anti-biofilm-forming properties. These results will set the stage to develop antimicrobial nanoparticle formulations for applications in chronic wound treatment.

  4. Nitric Oxide Synthase in Spontaneously Hypertensive Rats.

    PubMed

    Wu, Ch.Ch.; Yen, M.-H.

    1997-01-01

    Since its discovery by Furchgott and Zawadzki in 1980 [18], endothelium-derived relaxing factor (EDRF) has been shown to play a central role in the cardiovascular system [10]. The endothelial product is chemically equivalent to nitric oxide (NO) [23, 40] or a biochemical congener thereof [48]. Fifteen years ago, this small, simple and highly toxic molecule was known as a lengthy list of environmental pollutants found in unsavory haunts such as smoke and smog, and even as destroyer of ozone, suspected carcinogen, and precursor of acid rain. In addition, NO seems an unlikely biological jack of all trades for most of the body's functions are regulated by extraordinarily large and complex proteins and compounds. But over the past decade, diverse lines of evidence have converged to show that this sometime poison is a fundamental player in the everyday business of the human body.

  5. Nitric oxide: a synchronizing chemical messenger.

    PubMed

    Anbar, M

    1995-06-14

    Nitric oxide (NO) has been recognized as a ubiquitous chemical messenger in a large number of different biological systems. Its chemical properties make it less specific and less controllable than practically any other neurotransmitter or hormone. In view of this, its extensive biological role as a chemical messenger seems surprising. It is suggested that the biological function of NO evolved early in the anaerobic stage of evolution. In view of its low molecular weight, limited interaction with water, and its electrical neutrality, which allow it to diffuse rapidly through the cytoplasm and biomembranes, it is suggested that the need for NO has been retained by and maintained in eukaryote cells because of its ability to affect many biochemical functions simultaneously, acting primarily as an intracellular synchronizing chemical messenger.

  6. Nitric oxide-releasing porous silicon nanoparticles

    PubMed Central

    2014-01-01

    In this study, the ability of porous silicon nanoparticles (PSi NPs) to entrap and deliver nitric oxide (NO) as an effective antibacterial agent is tested against different Gram-positive and Gram-negative bacteria. NO was entrapped inside PSi NPs functionalized by means of the thermal hydrocarbonization (THC) process. Subsequent reduction of nitrite in the presence of d-glucose led to the production of large NO payloads without reducing the biocompatibility of the PSi NPs with mammalian cells. The resulting PSi NPs demonstrated sustained release of NO and showed remarkable antibacterial efficiency and anti-biofilm-forming properties. These results will set the stage to develop antimicrobial nanoparticle formulations for applications in chronic wound treatment. PMID:25114633

  7. Nitric oxide in liver fibrosis: The role of inducible nitric oxide synthase.

    PubMed

    Iwakiri, Yasuko

    2015-12-01

    The inducible form of nitric oxide synthase (iNOS) is expressed in hepatic cells in pathological conditions. Its induction is involved in the development of liver fibrosis, and thus iNOS could be a therapeutic target for liver fibrosis. This review summarizes the role of iNOS in liver fibrosis, focusing on 1) iNOS biology, 2) iNOS-expressing liver cells, 3) iNOS-related therapeutic strategies, and 4) future directions.

  8. Nitric oxide in liver fibrosis: The role of inducible nitric oxide synthase

    PubMed Central

    2015-01-01

    The inducible form of nitric oxide synthase (iNOS) is expressed in hepatic cells in pathological conditions. Its induction is involved in the development of liver fibrosis, and thus iNOS could be a therapeutic target for liver fibrosis. This review summarizes the role of iNOS in liver fibrosis, focusing on 1) iNOS biology, 2) iNOS-expressing liver cells, 3) iNOS-related therapeutic strategies, and 4) future directions. PMID:26770919

  9. Nitric oxide is required for the auxin-induced activation of NADPH-dependent thioredoxin reductase and protein denitrosylation during root growth responses in arabidopsis

    PubMed Central

    Correa-Aragunde, Natalia; Cejudo, Francisco J.; Lamattina, Lorenzo

    2015-01-01

    Background and Aims Auxin is the main phytohormone controlling root development in plants. This study uses pharmacological and genetic approaches to examine the role of auxin and nitric oxide (NO) in the activation of NADPH-dependent thioredoxin reductase (NTR), and the effect that this activity has on root growth responses in Arabidopsis thaliana. Methods Arabidopsis seedlings were treated with auxin with or without the NTR inhibitors auranofin (ANF) and 1-chloro-2, 4-dinitrobenzene (DNCB). NTR activity, lateral root (LR) formation and S-nitrosothiol content were measured in roots. Protein S-nitrosylation was analysed by the biotin switch method in wild-type arabidopsis and in the double mutant ntra ntrb. Key Results The auxin-mediated induction of NTR activity is inhibited by the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (CPTIO), suggesting that NO is downstream of auxin in this regulatory pathway. The NTR inhibitors ANF and DNCB prevent auxin-mediated activation of NTR and LR formation. Moreover, ANF and DNCB also inhibit auxin-induced DR5 : : GUS and BA3 : : GUS gene expression, suggesting that the auxin signalling pathway is compromised without full NTR activity. Treatment of roots with ANF and DNCB increases total nitrosothiols (SNO) content and protein S-nitrosylation, suggesting a role of the NTR-thioredoxin (Trx)-redox system in protein denitrosylation. In agreement with these results, the level of S-nitrosylated proteins is increased in the arabidopsis double mutant ntra ntrb as compared with the wild-type. Conclusions The results support for the idea that NTR is involved in protein denitrosylation during auxin-mediated root development. The fact that a high NO concentration induces NTR activity suggests that a feedback mechanism to control massive and unregulated protein S-nitrosylation could be operating in plant cells. PMID:26229066

  10. [Nitric oxide is a major player in plant immune system].

    PubMed

    Koen, Emmanuel; Lamotte, Olivier; Besson-Bard, Angélique; Bourque, Stéphane; Nicolas-Francès, Valérie; Jeandroz, Sylvain; Wendehenne, David

    2013-03-01

    In animals, nitric oxide (NO) functions as a ubiquitous signaling molecule involved in diverse physiological processes such as immunity. Recent studies provided evidence that plants challenged by pathogenic microorganisms also produce NO. The emerging picture is that NO functions as a signal in plant immunity and executes part of its effects through posttranslational protein modifications. Notably, the characterization of S-nitrosylated proteins provided insights into the molecular mechanisms by which NO exerts its activities. Based on these findings, it appears that NO is involved in both the activation and the negative control of the signaling pathways related to plant immunity. PMID:23544386

  11. Crotamine stimulates phagocytic activity by inducing nitric oxide and TNF-α via p38 and NFκ-B signaling in RAW 264.7 macrophages

    PubMed Central

    Lee, Kyung Jin; Kim, Yun Kyu; Krupa, Martin; Nguyen, Anh Ngoc; Do, Bich Hang; Chung, Boram; Vu, Thi Thu Trang; Kim, Song Cheol; Choe, Han

    2016-01-01

    Crotamine is a peptide toxin found in the venom of the rattlesnake Crotalus durissus terrificus and has antiproliferative, antimicrobial, and antifungal activities. Herein, we show that crotamine dose-dependently induced macrophage phagocytic and cytostatic activity by the induction of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-α). Moreover, the crotamineinduced expression of iNOS and TNF-α is mediated through the phosphorylation of p38 and the NF-κB signaling cascade in macrophages. Notably, pretreatment with SB203580 (a p38-specific inhibitor) or BAY 11-7082 (an NF-κB inhibitor) inhibited crotamine-induced NO production and macrophage phagocytic and cytotoxic activity. Our results show for the first time that crotamine stimulates macrophage phagocytic and cytostatic activity by induction of NO and TNF-α via the p38 and NF-κB signaling pathways and suggest that crotamine may be a useful therapeutic agent for the treatment of inflammatory disease. [BMB Reports 2016; 49(3): 185-190] PMID:26818089

  12. Crotamine stimulates phagocytic activity by inducing nitric oxide and TNF-α via p38 and NFκ-B signaling in RAW 264.7 macrophages.

    PubMed

    Lee, Kyung Jin; Kim, Yun Kyu; Krupa, Martin; Nguyen, Anh Ngoc; Do, Bich Hang; Chung, Boram; Vu, Thi Thu Trang; Kim, Song Cheol; Choe, Han

    2016-03-01

    Crotamine is a peptide toxin found in the venom of the rattlesnake Crotalus durissus terrificus and has antiproliferative, antimicrobial, and antifungal activities. Herein, we show that crotamine dose-dependently induced macrophage phagocytic and cytostatic activity by the induction of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-α). Moreover, the crotamineinduced expression of iNOS and TNF-α is mediated through the phosphorylation of p38 and the NF-κB signaling cascade in macrophages. Notably, pretreatment with SB203580 (a p38-specific inhibitor) or BAY 11-7082 (an NF-κB inhibitor) inhibited crotamine-induced NO production and macrophage phagocytic and cytotoxic activity. Our results show for the first time that crotamine stimulates macrophage phagocytic and cytostatic activity by induction of NO and TNF-α via the p38 and NF-κB signaling pathways and suggest that crotamine may be a useful therapeutic agent for the treatment of inflammatory disease. [BMB Reports 2016; 49(3): 185-190]. PMID:26818089

  13. Netrin-1 Abrogates Ischemia Reperfusion-induced Cardiac Mitochondrial Dysfunction via Nitric Oxide-dependent Attenuation of NOX4 Activation and Recoupling of NOS

    PubMed Central

    Siu, Kin Lung; Lotz, Christopher; Ping, Peipei; Cai, Hua

    2014-01-01

    Despite an established role of mitochondrial dysfunction in cardiac ischemia reperfusion (I/R) injury, the upstream activators have remained incompletely defined. We have recently identified an innovative role of exogenously applied netrin-1 in cardioprotection, which is mediated by increased nitric oxide (NO) bioavailability. Here, we tested the hypothesis that this “pharmacological” treatment of netrin-1 preserves mitochondrial function via novel mechanisms that are NO dependent. Freshly isolated C57BL6 mouse hearts were perfused using a Langendorff system, and subjected to a 20 min global ischemia/60 min reperfusion, in the presence or absence of netrin-1. I/R induced marked increases in infarct size, total superoxide and hydrogen peroxide production, activity and protein abundance of NADPH oxidase (NOX) isoform 4 (NOX4), as well as impaired mitochondrial integrity and function, all of which were attenuated by netrin-1. This protective effect of netrin-1 is attributed to cGMP, a downstream effector of NO. The protein levels of NOX1 and NOX2 were however unaffected, and infarct size from NOX1 and NOX2 knockouts were not different from wild type animals. Scavenging of NO with PTIO reversed inhibitory effects of netrin-1 on NOX4, while NO donor attenuated NOX4 protein abundance. In vivo NOX4 RNAi, or sepiapterin perfusion, resulted in recoupling of NOS, decreased infarct size, and blockade of dysfunctional mitochondrial swelling and mitochondrial superoxide production. These data demonstrate that netrin-1 induces cardioprotection through inhibition of NOX4 activity, which leads to recoupling of NOS, augmented NO bioavailability, reduction in oxidative stress, and ultimately preservation of mitochondrial function. The NO-dependent NOX4 inhibition connects with our previously established pathway of DCC/ERK1/2/eNOS/NO/DCC feed-forward mechanism, to maintain NOS in the coupling state to attenuate oxidative stress to preserve mitochondrial function. These findings

  14. Anticancer efficacy of a nitric oxide-modified derivative of bifendate against multidrug-resistant cancer cells.

    PubMed

    Ren, Zhiguang; Gu, Xiaoke; Lu, Bin; Chen, Yaqiong; Chen, Guojiang; Feng, Jiannan; Lin, Jizhen; Zhang, Yihua; Peng, Hui

    2016-06-01

    The development of multidrug resistance (MDR) not only actively transports a wide range of cytotoxic drugs across drug transporters but is also a complex interaction between a number of important cellular signalling pathways. Nitric oxide donors appear to be a new class of anticancer therapeutics for satisfying all the above conditions. Previously, we reported furoxan-based nitric oxide-releasing compounds that exhibited selective antitumour activity in vitro and in vivo. Herein, we demonstrate that bifendate (DDB)-nitric oxide, a synthetic furoxan-based nitric oxide-releasing derivative of bifendate, effectively inhibits the both sensitive and MDR tumour cell viability at a comparatively low concentration. Interestingly, the potency of DDB-nitric oxide is the independent of inhibition of the functions and expressions of three major ABC transporters. The mechanism of DDB-nitric oxide appears to be in two modes of actions by inducing mitochondrial tyrosine nitration and apoptosis, as well as by down-regulating HIF-1α expression and protein kinase B (AKT), extracellular signal-regulated kinases (ERK), nuclear factor κB (NF-κB) activation in MDR cells. Moreover, the addition of a typical nitric oxide scavenger significantly attenuated all the effects of DDB-nitric oxide, indicating that the cytotoxicity of DDB-nitric oxide is as a result of higher levels of nitric oxide release in MDR cancer cells. Given that acquired MDR to nitric oxide donors is reportedly difficult to achieve and genetically unstable, compound like DDB-nitric oxide may be a new type of therapeutic agent for the treatment of MDR tumours.

  15. Advanced glycosylation products quench nitric oxide and mediate defective endothelium-dependent vasodilatation in experimental diabetes.

    PubMed Central

    Bucala, R; Tracey, K J; Cerami, A

    1991-01-01

    Nitric oxide (an endothelium-derived relaxing factor) induces smooth muscle relaxation and is an important mediator in the regulation of vascular tone. Advanced glycosylation end products, the glucose-derived moieties that form nonenzymatically and accumulate on long-lived tissue proteins, have been implicated in many of the complications of diabetes and normal aging. We demonstrate that advanced glycosylation products quench nitric oxide activity in vitro and in vivo. Acceleration of the advanced glycosylation process in vivo results in a time-dependent impairment in endothelium-dependent relaxation. Inhibition of advanced glycosylation with aminoguanidine prevents nitric oxide quenching, and ameliorates the vasodilatory impairment. These results implicate advanced glycosylation products as important modulators of nitric oxide activity and endothelium-dependent relaxation. PMID:1991829

  16. Antagonism of the antinociceptive effect of nitrous oxide by inhibition of enzyme activity or expression of neuronal nitric oxide synthase in the mouse brain and spinal cord.

    PubMed

    Cope, Jessica Lack; Chung, Eunhee; Ohgami, Yusuke; Quock, Raymond M

    2010-01-25

    Previous studies have implicated nitric oxide (NO) in the antinociceptive response to the anesthetic gas nitrous oxide (N(2)O). The present study was conducted to confirm this NO involvement using pharmacological and gene knockdown and knockout strategies to inhibit the supraspinal and spinal production of NO. Antinociceptive responsiveness to 70% N(2)O was assessed using the acetic acid (0.6%) abdominal constriction test in NIH Swiss mice following intracerebroventricular (i.c.v.) or intrathecal (i.t.) pretreatment with the NOS-inhibitor l-N(G)-nitro arginine methyl ester (L-NAME) or an antisense oligodeoxynucleotide (AS-ODN) directed against neuronal NOS (nNOS). Experiments were also conducted in mice homozygous for a defective nNOS gene (nNOS(-/-)). Mice that were pretreated i.c.v. or i.t. with L-NAME (1.0 microg) both exhibited 80-90% reduction in the magnitude of the N(2)O-induced antinociceptive response. Mice that were pretreated i.c.v. or i.t. with nNOS AS-ODN (3 x 25microg) exhibited a 60-80% antagonism of the antinociceptive response. Compared to wild-type mice, nNOS knockout mice showed a 60% reduction in N(2)O-induced antinociception. These findings consistently demonstrate that transient or developmental suppression of nNOS expression significantly reduces antinociceptive responsiveness to N(2)O. NO of both supraspinal and spinal origin, therefore, plays an important role in the antinociceptive response to N(2)O. PMID:19818753

  17. Effect of simulated microgravity on nitric oxide synthase activity of osteocyte-like cell line MLO-Y4 in response to fluid shear stress

    NASA Astrophysics Data System (ADS)

    Sun, Lian-Wen; Yang, Xiao; Fan, Yu-Bo

    It is well known that microgravity could induce bone loss. However, the mechanism remains poorly understood. Osteocytes are extremely sensitive to fluid shear stress, even more than osteobleasts. The effect of simulated microgravity on osteocytes in response to fluid shear was investigated in this study in order to see if the mechanosensibility of osteocytes changed under simulated microgravity. The osteocyte-like cell line, MLO-Y4, was cultured and divided into four groups, including control (CON), control and shear (CONS), rotary (RT), rotary and shear (RTS). In RT and RTS, the cells were cultured in the rotary cell culture system to simulate microgravity condition. After 5 days, the cells in RTS and CONS were subjected to flow shear for 15 min. Then nitric oxide synthase (NOS) activity in the cells was measured using assay kit. The results showed that NOS activity in respond to fluid shear decreased significantly in RTS compared with CONS. In addition, there was significant difference in NOS activity between CONS and CON while no significant difference between RTS and RT. These indicates that the mechanosensibility of osteocytes decreased under simulated microgravity and this maybe the partly causes of the poor effect of exercise to counter microgravity-induced-bone loss. However, further research need to be done to support this finding.

  18. The Oxyhemoglobin Reaction of Nitric Oxide

    NASA Astrophysics Data System (ADS)

    Gow, Andrew J.; Luchsinger, Benjamin P.; Pawloski, John R.; Singel, David J.; Stamler, Jonathan S.

    1999-08-01

    The oxidation of nitric oxide (NO) to nitrate by oxyhemoglobin is a fundamental reaction that shapes our understanding of NO biology. This reaction is considered to be the major pathway for NO elimination from the body; it is the basis for a prevalent NO assay; it is a critical feature in the modeling of NO diffusion in the circulatory system; and it informs a variety of therapeutic applications, including NO-inhalation therapy and blood substitute design. Here we show that, under physiological conditions, this reaction is of little significance. Instead, NO preferentially binds to the minor population of the hemoglobin's vacant hemes in a cooperative manner, nitrosylates hemoglobin thiols, or reacts with liberated superoxide in solution. In the red blood cell, superoxide dismutase eliminates superoxide, increasing the yield of S-nitrosohemoglobin and nitrosylated hemes. Hemoglobin thus serves to regulate the chemistry of NO and maintain it in a bioactive state. These results represent a reversal of the conventional view of hemoglobin in NO biology and motivate a reconsideration of fundamental issues in NO biochemistry and therapy.

  19. Functional link between TNF biosynthesis and CaM-dependent activation of inducible nitric oxide synthase in RAW 264.7 macrophages

    SciTech Connect

    Weber, Thomas J; Smallwood, Heather S; Kathmann, Loel E; Markillie, Lye MENG; Squier, Thomas C; Thrall, Brian D

    2006-01-18

    Inflammatory responses stimulated by bacterial endotoxin (lipopolysaccharide, LPS) involve calcium-mediated signaling, yet the cellular sensors that determine cell fate in response to LPS remain poorly understood. We report that exposure of RAW 264.7 macrophage-like cells to LPS induces a rapid increase in calmodulin (CaM) abundance, which is associated with the modulation of the inflammatory response. Increases in CaM abundance precedes nuclear localization of key transcription factors (i.e., NFκB p65 subunit, phospho-c-Jun, and Sp1) and subsequent increases in the pro-inflammatory cytokine tumor necrosis factor α (TNF) and inducible nitric oxide synthase (iNOS). Cellular apoptosis following LPS challenge is blocked following inhibition of iNOS activity, whether accomplished using the pharmacological inhibitor 1400W, through gene silencing of TNFα, or by increasing the level of cellular CaM by stable transfection. Increasing CaM expression also results in reductions in the cellular release of TNFα and iNOS, and activation of their transcriptional regulators, indicating the level of available CaM plays a key role in determining the expression of the pro-inflammatory and pro-apoptotic cascade during cellular activation by LPS. These results indicate a previously unrecognized central role for CaM in maintaining cellular homeostasis in response to LPS, such that under resting conditions cellular concentrations of CaM are sufficient to inhibit the biosynthesis of proinflammatory mediators associated with macrophage activation. Although CaM and iNOS protein levels are coordinately increased as part of the oxidative burst, limiting cellular concentrations of CaM due to association with iNOS (and other high-affinity binders) commit the cell to an unchecked inflammatory cascade leading to apoptosis.

  20. Implications of glial nitric oxide in neurodegenerative diseases

    PubMed Central

    Yuste, Jose Enrique; Tarragon, Ernesto; Campuzano, Carmen María; Ros-Bernal, Francisco

    2015-01-01

    Nitric oxide (NO) is a pleiotropic janus-faced molecule synthesized by nitric oxide synthases (NOS) which plays a critical role in a number of physiological and pathological processes in humans. The physiological roles of NO depend on its local concentrations, as well as its availability and the nature of downstream target molecules. Its double-edged sword action has been linked to neurodegenerative disorders. Excessive NO production, as the evoked by inflammatory signals, has been identified as one of the major causative reasons for the pathogenesis of several neurodegenerative diseases. Moreover, excessive NO synthesis under neuroinflammation leads to the formation of reactive nitrogen species and neuronal cell death. There is an intimate relation between microglial activation, NO and neuroinflammation in the human brain. The role of NO in neuroinflammation has been defined in animal models where this neurotransmitter can modulate the inflammatory process acting on key regulatory pathways, such as those associated with excitotoxicity processes induced by glutamate accumulation and microglial activation. Activated glia express inducible NOS and produce NO that triggers calcium mobilization from the endoplasmic reticulum, activating the release of vesicular glutamate from astroglial cells resulting in neuronal death. This change in microglia potentially contributes to the increased age-associated susceptibility and neurodegeneration. In the current review, information is provided about the role of NO, glial activation and age-related processes in the central nervous system (CNS) that may be helpful in the isolation of new therapeutic targets for aging and neurodegenerative diseases. PMID:26347610

  1. Implications of glial nitric oxide in neurodegenerative diseases.

    PubMed

    Yuste, Jose Enrique; Tarragon, Ernesto; Campuzano, Carmen María; Ros-Bernal, Francisco

    2015-01-01

    Nitric oxide (NO) is a pleiotropic janus-faced molecule synthesized by nitric oxide synthases (NOS) which plays a critical role in a number of physiological and pathological processes in humans. The physiological roles of NO depend on its local concentrations, as well as its availability and the nature of downstream target molecules. Its double-edged sword action has been linked to neurodegenerative disorders. Excessive NO production, as the evoked by inflammatory signals, has been identified as one of the major causative reasons for the pathogenesis of several neurodegenerative diseases. Moreover, excessive NO synthesis under neuroinflammation leads to the formation of reactive nitrogen species and neuronal cell death. There is an intimate relation between microglial activation, NO and neuroinflammation in the human brain. The role of NO in neuroinflammation has been defined in animal models where this neurotransmitter can modulate the inflammatory process acting on key regulatory pathways, such as those associated with excitotoxicity processes induced by glutamate accumulation and microglial activation. Activated glia express inducible NOS and produce NO that triggers calcium mobilization from the endoplasmic reticulum, activating the release of vesicular glutamate from astroglial cells resulting in neuronal death. This change in microglia potentially contributes to the increased age-associated susceptibility and neurodegeneration. In the current review, information is provided about the role of NO, glial activation and age-related processes in the central nervous system (CNS) that may be helpful in the isolation of new therapeutic targets for aging and neurodegenerative diseases. PMID:26347610

  2. Shear-Induced Nitric Oxide Production by Endothelial Cells.

    PubMed

    Sriram, Krishna; Laughlin, Justin G; Rangamani, Padmini; Tartakovsky, Daniel M

    2016-07-12

    We present a biochemical model of the wall shear stress-induced activation of endothelial nitric oxide synthase (eNOS) in an endothelial cell. The model includes three key mechanotransducers: mechanosensing ion channels, integrins, and G protein-coupled receptors. The reaction cascade consists of two interconnected parts. The first is rapid activation of calcium, which results in formation of calcium-calmodulin complexes, followed by recruitment of eNOS from caveolae. The second is phosphorylation of eNOS by protein kinases PKC and AKT. The model also includes a negative feedback loop due to inhibition of calcium influx into the cell by cyclic guanosine monophosphate (cGMP). In this feedback, increased nitric oxide (NO) levels cause an increase in cGMP levels, so that cGMP inhibition of calcium influx can limit NO production. The model was used to predict the dynamics of NO production by an endothelial cell subjected to a step increase of wall shear stress from zero to a finite physiologically relevant value. Among several experimentally observed features, the model predicts a highly nonlinear, biphasic transient behavior of eNOS activation and NO production: a rapid initial activation due to the very rapid influx of calcium into the cytosol (occurring within 1-5 min) is followed by a sustained period of activation due to protein kinases. PMID:27410748

  3. Shear-Induced Nitric Oxide Production by Endothelial Cells

    NASA Astrophysics Data System (ADS)

    Sriram, Krishna; Laughlin, Justin G.; Rangamani, Padmini; Tartakovsky, Daniel M.

    2016-07-01

    We present a biochemical model of the wall shear stress (WSS)-induced activation of endothelial nitric oxide synthase (eNOS) in an endothelial cell (EC). The model includes three key mechanotransducers: mechanosensing ion channels, integrins and G-protein-coupled receptors. The reaction cascade consists of two interconnected parts. The first is rapid activation of calcium, which results in formation of calcium-calmodulin complexes, followed by recruitment of eNOS from caveolae. The second is phosphoryaltion of eNOS by protein kinases PKC and AKT. The model also includes a negative feedback loop due to inhibition of calcium influx into the cell by cyclic guanosine monophosphate (cGMP). In this feedback, increased nitric oxide (NO) levels cause an increase in cGMP levels, so that cGMP inhibition of calcium influx can limit NO production. The model was used to predict the dynamics of NO production by an EC subjected to a step increase of WSS from zero to a finite physiologically relevant value. Among several experimentally observed features, the model predicts a highly nonlinear, biphasic transient behavior of eNOS activation and NO production: a rapid initial activation due to the very rapid influx of calcium into the cytosol (occurring within 1 to 5 minutes) is followed by a sustained period of activation due to protein kinases.

  4. Nitric oxide scavengers differentially inhibit ammonia oxidation in ammonia-oxidizing archaea and bacteria.

    PubMed

    Sauder, Laura A; Ross, Ashley A; Neufeld, Josh D

    2016-04-01

    Differential inhibitors are important for measuring the relative contributions of microbial groups, such as ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), to biogeochemical processes in environmental samples. In particular, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO) represents a nitric oxide scavenger used for the specific inhibition of AOA, implicating nitric oxide as an intermediate of thaumarchaeotal ammonia oxidation. This study investigated four alternative nitric oxide scavengers for their ability to differentially inhibit AOA and AOB in comparison to PTIO. Caffeic acid, curcumin, methylene blue hydrate and trolox were tested onNitrosopumilus maritimus, two unpublished AOA representatives (AOA-6f and AOA-G6) as well as the AOB representative Nitrosomonas europaea All four scavengers inhibited ammonia oxidation by AOA at lower concentrations than for AOB. In particular, differential inhibition of AOA and AOB by caffeic acid (100 μM) and methylene blue hydrate (3 μM) was comparable to carboxy-PTIO (100 μM) in pure and enrichment culture incubations. However, when added to aquarium sponge biofilm microcosms, both scavengers were unable to inhibit ammonia oxidation consistently, likely due to degradation of the inhibitors themselves. This study provides evidence that a variety of nitric oxide scavengers result in differential inhibition of ammonia oxidation in AOA and AOB, and provides support to the proposed role of nitric oxide as a key intermediate in the thaumarchaeotal ammonia oxidation pathway.

  5. Lipopolysaccharide-induced murine embryonic resorption involves nitric oxide-mediated inhibition of the NAD+-dependent 15-hydroxyprostaglandin dehydrogenase.

    PubMed

    Aisemberg, Julieta; Bariani, María V; Vercelli, Claudia A; Wolfson, Manuel L; Franchi, Ana M

    2012-10-01

    The initial inactivation of prostaglandins (PGs) is mediated by 15-hydroxyprostaglandin dehydrogenase (15-PGDH). PGs are potent mediators of several biological processes, including inflammation and reproduction. In uterus, PGs play a key role in infection-induced pregnancy loss, in which concentration of this mediator increased. This process is accompanied with the induction of nitric oxide synthase expression and a marked increase in uterine levels of nitric oxide. There is no information concerning nitric oxide contribution to potential changes in PG catabolism, but experimental evidence suggests that nitric oxide modulates PG pathways. The specific objectives of the study were to evaluate the protein expression of HPGD (15-PGDH) and to characterize the nitric oxide-dependent regulation of this enzyme in a model of lipopolysaccharide (LPS)-induced embryonic resorption. Results show that LPS decreased HPGD protein expression and augmented PGE synthase activity; therefore, PGE₂ levels increased in uterus in this inflammatory condition. Just as LPS, the treatment with a nitric oxide donor diminished HPGD protein expression in uterine tissue. In contrast, the inhibition of nitric oxide synthesis both in control and in LPS-treated mice increased 15-PGDH levels. Also, we have found that this enzyme and PGE₂ levels are not modulated by peroxynitrite, an oxidant agent derived from nitric oxide. This study suggests that LPS and nitric oxide promote a decrease in the ability of the uterus for PG catabolism during bacterially triggered pregnancy loss in mice. PMID:22843771

  6. Nitric oxide and cell death in liver cancer cells.

    PubMed

    Muntané, Jordi; De la Rosa, Angel J; Marín, Luís M; Padillo, Francisco J

    2013-05-01

    Nitric oxide (NO) is a lipophillic, highly diffusible, and short-lived physiological messenger which regulates a variety of physiopathological responses. NO may exert its cellular action through cGMP-dependent and cGMP-independent pathways which includes different postranslational modifications. The effect of NO in cancer depends on the activity and localization of NOS isoforms, concentration and duration of NO exposure, cellular sensitivity, and hypoxia/re-oxygenation process. NO regulates critical factors such as the hypoxia inducible factor-1 (HIF-1) and p53 generally leading to growth arrest, apoptosis or adaptation. NO sensitizes hepatoma cells to chemotherapeutic compounds probably through increased p53 and cell death receptor expressions.

  7. Application of nitric oxide measurements in clinical conditions beyond asthma

    PubMed Central

    Malinovschi, Andrei; Ludviksdottir, Dora; Tufvesson, Ellen; Rolla, Giovanni; Bjermer, Leif; Alving, Kjell; Diamant, Zuzana

    2015-01-01

    Fractional exhaled nitric oxide (FeNO) is a convenient, non-invasive method for the assessment of active, mainly Th2-driven, airway inflammation, which is sensitive to treatment with standard anti-inflammatory therapy. Consequently, FeNO serves as a valued tool to aid diagnosis and monitoring in several asthma phenotypes. More recently, FeNO has been evaluated in several other respiratory, infectious, and/or immunological conditions. In this short review, we provide an overview of several clinical studies and discuss the status of potential applications of NO measurements in clinical conditions beyond asthma. PMID:26672962

  8. Nitric Oxide-Releasing Dendrimers as Antibacterial Agents

    PubMed Central

    Sun, Bin; Slomberg, Danielle L.; Chudasama, Shalini L.; Lu, Yuan

    2012-01-01

    The antibacterial activity of a series of nitric oxide (NO)-releasing poly(propylene imine) (PPI) dendrimers was evaluated against both Gram-positive and Gram-negative pathogenic bacteria, including methicillin-resistant Staphylococcus aureus. A direct comparison of the bactericidal efficacy between NO-releasing and control PPI dendrimers (i.e., non-NO-releasing) revealed both enhanced biocidal action of NO-releasing dendrimers and reduced toxicity against mammalian fibroblast cells. Antibacterial activity for the NO donor-functionalized PPI dendrimers was shown to be a function of both dendrimer size (molecular weight) and exterior functionality. In addition to minimal toxicity against fibroblasts, NO-releasing PPI dendrimers modified with styrene oxide exhibited the greatest biocidal activity (≥9.999% killing) against all bacterial strains tested. The N-diazeniumdiolate NO donor-functionalized PPI dendrimers presented in this study hold promise as effective NO-based therapeutics for combating bacterial infections. PMID:23013537

  9. Targeted nitric oxide delivery preferentially induces glioma cell chemosensitivity via altered p53 and O(6) -methylguanine-DNA methyltransferase activity.

    PubMed

    Safdar, Shahana; Payne, Courtney A; Tu, Nam H; Taite, Lakeshia J

    2013-04-01

    Glioblastoma multiforme is the most common malignant central nervous system tumor, and also among the most difficult to treat due to a lack of response to chemotherapeutics. New methods of countering the mechanisms that confer chemoresistance to malignant gliomas could lead to significant advances in the quest to identify novel drug combinations or targeted drug delivery systems for cancer therapy. In this study, we investigate the use of a targeted nitric oxide (NO) donor as a pretreatment to sensitize glioma cells to chemotherapy. The protein chlorotoxin (CTX) has been shown to preferentially target glioma cells, and we have developed CTX-NO, a glioma-specific, NO-donating CTX derivative. Pretreatment of cells with CTX-NO followed by 48-h exposure to either carmustine (BCNU) or temozolomide (TMZ), both common chemotherapeutics used in glioma treatment, resulted in increased efficacy of both therapeutics. After CTX-NO exposure, both T98G and U-87MG human malignant glioma cells show increased sensitivity to BCNU and TMZ. Further investigation revealed that the consequences of this combination therapy was a reduction in active levels of the cytoprotective enzyme MGMT and altered p53 activity, both of which are essential in DNA repair and tumor cell resistance to chemotherapy. The combination of CTX-NO and chemotherapeutics also led to decreased cell invasion. These studies indicate that this targeted NO donor could be an invaluable tool in the development of novel approaches to treat cancer.

  10. Nitric Oxide and the Biological Cascades Underlying Increased Neurogenesis, Enhanced Learning Ability, and Academic Ability as an Effect of Increased Bouts of Physical Activity

    PubMed Central

    HUNT, SAMUEL J.; NAVALTA, JAMES W.

    2012-01-01

    The consummate principle underlying all physiological research is corporeal adaptation at every level of the organism observed. With respect to humans, the body learns to function based on the external stimuli from the environment, beginning in the womb, throughout the developmental stages of life. Nitric Oxide (NO) appears to be the governor of the plasticity of several systems in mammals implicit in their proper development. It is the purpose of this review to describe the physiological pathways that lead to plasticity of not only the vasculature but also of the brain and how physical activity plays a key role in those alterations by initiating the mechanism that triggers NO production. Further, this review hopes to show a connection between these changes and learning, comprising both motor learning and cognitive learning. This review will show how NO plays a significant role in vascularization and neurogenesis, necessary to enhance the mind-body connection and comprehensive physical performance and adaptation. It is our belief that this review effectively demonstrates, using a multidisciplinary approach, the causal mechanisms underlying the increases in neurogenesis as related to improved learning and academic performance as a result of adequate bouts of physical activity of a vigorous nature. PMID:27182387

  11. A quantitative structure-activity relationship (QSAR) study on a few series of potent, highly selective inhibitors of nitric oxide synthase.

    PubMed

    Bharti, Vishwa Deepak; Gupta, Satya P; Kumar, Harish

    2014-02-01

    QSAR study was performed on a series of 1,2-dihydro-4-quinazolinamines, 4,5-dialkylsubstituted-2-imino-1,3-thiazolidine derivatives and 4,5-disubstituted-1,3-oxazolidin-2-imine derivatives studied by Tinker et al. [J Med Chem (2003), 46, 913-916], Ueda et al. [Bioorg Med Chem (2004) 12, 4101-4116] and Ueda et al. [Bioorg Med Chem Lett (2004) 14, 313-316], respectively, as potent, highly selective inhibitors of inducible nitric oxide synthase (iNOS). The iNOS inhibition activity of the whole series of compounds was analyzed in relation to the physicochemical and molecular properties of the compounds. The QSAR analysis revealed that the inhibition potency of the compounds was controlled by a topological parameter 1chi(v) (Kier's first order valence molecular connectivity index), density (D), surface tension (St) and length (steric parameter) of a substituent. This suggested that the drug-receptor interaction predominantly involved the dispersion interaction, but the bulky molecule would face steric problem because of which the molecule may not completely fit in active sites of the receptor and thus may not have the optimum interaction.

  12. Nitric Oxide Plasma Sources for Bio-Decontamination and Plasma Therapy

    NASA Astrophysics Data System (ADS)

    Vasilets, Victor N.; Shekhter, Anatoly B.

    One of the main products generated in atmospheric plasma sources is nitric oxide. The nitric oxide molecule is known as anti-bacterial agent on one hand and the molecule providing signaling and regulation biological functions on the other hand. Human body produces NO to kill invading pathogens. At the same time nitric oxide works as a primary vasoregulator and anti-hypertensive agent. NO also ­regulates: inflammation, collagen production, angiogenesis and apoptosis. Exogenous NO generated by plasma devices could enhance bio-activity of NO-assisted ­processes in human organism. Some applications of nitric oxide for bio-decontamination and plasma therapy will be illustrated and discussed in the paper.

  13. What is nitric oxide and why are so many people studying it?

    PubMed

    Gibaldi, M

    1993-06-01

    From social outcast to citizen of the year in less than a decade is the stuff of fiction. That is precisely what has happened, however, to a remarkably simple molecule, nitric oxide. Nitric oxide is still an environmental pollutant, suspected carcinogen, and precursor of acid rain, but biologists are looking past its dark side. They now see a molecule that is uniting neuroscience, physiology, and immunology. Its ubiquitous distribution in the body and its multifaceted roles are revising our understanding of how cells communicate and protect themselves. This report examines nitric oxide's role in physiology and pathophysiology and reviews novel therapeutic approaches which involve inhibition or induction of the activity of endogenous nitric oxide.

  14. Nitric oxide mediates glutamate-linked enhancement of cGMP levels in the cerebellum

    SciTech Connect

    Bredt, D.S.; Snyder, S.H. )

    1989-11-01

    Nitric oxide, which mediates influences of numerous neurotransmitters and modulators on vascular smooth muscle and leukocytes, can be formed in the brain from arginine by an enzymatic activity that stoichiometrically generates citrulline. The authors show that glutamate and related amino acids, such as N-methyl-D-aspartate, markedly stimulate arginine-citrulline transformation in cerebellar slices stoichiometrically with enhancement of cGMP levels. N{sup {omega}}-monomethyl-L-arginine blocks the augmentation both of citrulline and cGMP with identical potencies. Arginine competitively reverses both effects of N{sup {omega}}-monomethyl-L-arginine with the same potencies. Hemoglobin, which complexes nitric oxide, prevents the stimulation by N-methyl-D-aspartate of cGMP levels, and superoxide dismutase, which elevates nitric oxide levels, increases cGMP formation. These data establish that nitric oxide mediates the stimulation by glutamate of cGMP formation.

  15. Nitric Oxide Mediates Glutamate-Linked Enhancement of cGMP Levels in the Cerebellum

    NASA Astrophysics Data System (ADS)

    Bredt, David S.; Snyder, Solomon H.

    1989-11-01

    Nitric oxide, which mediates influences of numerous neurotransmitters and modulators on vascular smooth muscle and leukocytes, can be formed in the brain from arginine by an enzymatic activity that stoichiometrically generates citrulline. We show that glutamate and related amino acids, such as N-methyl-D-aspartate, markedly stimulate arginine-citrulline transformation in cerebellar slices stoichiometrically with enhancement of cGMP levels. Nω-monomethyl-L-arginine blocks the augmentation both of citrulline and cGMP with identical potencies. Arginine competitively reverses both effects of Nω-monomethyl-L-arginine with the same potencies. Hemoglobin, which complexes nitric oxide, prevents the stimulation by N-methyl-D-aspartate of cGMP levels, and superoxide dismutase, which elevates nitric oxide levels, increases cGMP formation. These data establish that nitric oxide mediates the stimulation by glutamate of cGMP formation.

  16. Endothelial Caveolar Subcellular Domain Regulation of Endothelial Nitric Oxide Synthase

    PubMed Central

    Ramadoss, Jayanth; Pastore, Mayra B.; Magness, Ronald R.

    2015-01-01

    SUMMARY Complex regulatory processes alter the activity of endothelial nitric oxide synthase (eNOS) leading to nitric oxide (NO) production by endothelial cells under various physiological states. These complex processes require specific sub-cellular eNOS partitioning between plasma membrane caveolar domains and non-caveolar compartments.eNOS translocation from the plasma membrane to intracellular compartments is important for eNOS activation and subsequent NO biosynthesis. We present data reviewing and interpreting information: 1) the coupling of endothelial plasma membrane receptor systems in the caveolar structure relative to eNOS trafficking; 2) how eNOS trafficking relates to specific protein-protein interaction for inactivation and activation of eNOS; and 3) how these complex mechanisms confer specific subcellular location relative to eNOS multi-site phosphorylation and signaling.Dysfunction in regulation of eNOS activation may contribute to several disease states; in particular gestational endothelial abnormalities (preeclampsia, gestational diabetes, etc) that have life-long deleterious health consequences that predispose the offspring to develop hypertensive disease, type II diabetes and adiposity.1 PMID:23745825

  17. Comparison of control of Listeria by nitric oxide redox chemistry from murine macrophages and NO donors: insights into listeriocidal activity of oxidative and nitrosative stress.

    PubMed

    Ogawa, R; Pacelli, R; Espey, M G; Miranda, K M; Friedman, N; Kim, S M; Cox, G; Mitchell, J B; Wink, D A; Russo, A

    2001-02-01

    The physiological function of nitric oxide (NO) in the defense against pathogens is multifaceted. The exact chemistry by which NO combats intracellular pathogens such as Listeria monocytogenes is yet unresolved. We examined the effects of NO exposure, either delivered by NO donors or generated in situ within ANA-1 murine macrophages, on L. monocytogenes growth. Production of NO by the two NONOate compounds PAPA/NO (NH2(C3H6)(N[N(O)NO]C3H7) and DEA/NO (Na(C2H5)2N[N(O)NO]) resulted in L. monocytogenes cytostasis with minimal cytotoxicity. Reactive oxygen species generated from xanthine oxidase/hypoxanthine were neither bactericidal nor cytostatic and did not alter the action of NO. L. monocytogenes growth was also suppressed upon internalization into ANA-1 murine macrophages primed with interferon-gamma (INF-gamma) + tumor necrosis factor-alpha (TNF-alpha or INF-gamma + lipid polysaccharide (LPS). Growth suppression correlated with nitrite formation and nitrosation of 2,3-diaminonaphthalene elicited by stimulated murine macrophages. This nitrosative chemistry was not dependent upon nor mediated by interaction with reactive oxygen species (ROS), but resulted solely from NO and intermediates related to nitrosative stress. The role of nitrosation in controlling L. monocytogenes was further examined by monitoring the effects of exposure to NO on an important virulence factor, Listeriolysin O, which was inhibited under nitrosative conditions. These results suggest that nitrosative stress mediated by macrophages is an important component of the immunological arsenal in controlling L. monocytogenes infections. PMID:11165873

  18. T Cell Cancer Therapy Requires CD40-CD40L Activation of Tumor Necrosis Factor and Inducible Nitric-Oxide-Synthase-Producing Dendritic Cells.

    PubMed

    Marigo, Ilaria; Zilio, Serena; Desantis, Giacomo; Mlecnik, Bernhard; Agnellini, Andrielly H R; Ugel, Stefano; Sasso, Maria Stella; Qualls, Joseph E; Kratochvill, Franz; Zanovello, Paola; Molon, Barbara; Ries, Carola H; Runza, Valeria; Hoves, Sabine; Bilocq, Amélie M; Bindea, Gabriela; Mazza, Emilia M C; Bicciato, Silvio; Galon, Jérôme; Murray, Peter J; Bronte, Vincenzo

    2016-09-12

    Effective cancer immunotherapy requires overcoming immunosuppressive tumor microenvironments. We found that local nitric oxide (NO) production by tumor-infiltrating myeloid cells is important for adoptively transferred CD8(+) cytotoxic T cells to destroy tumors. These myeloid cells are phenotypically similar to inducible nitric oxide synthase (NOS2)- and tumor necrosis factor (TNF)-producing dendritic cells (DC), or Tip-DCs. Depletion of immunosuppressive, colony stimulating factor 1 receptor (CSF-1R)-dependent arginase 1(+) myeloid cells enhanced NO-dependent tumor killing. Tumor elimination via NOS2 required the CD40-CD40L pathway. We also uncovered a strong correlation between survival of colorectal cancer patients and NOS2, CD40, and TNF expression in their tumors. Our results identify a network of pro-tumor factors that can be targeted to boost cancer immunotherapies.

  19. T Cell Cancer Therapy Requires CD40-CD40L Activation of Tumor Necrosis Factor and Inducible Nitric-Oxide-Synthase-Producing Dendritic Cells.

    PubMed

    Marigo, Ilaria; Zilio, Serena; Desantis, Giacomo; Mlecnik, Bernhard; Agnellini, Andrielly H R; Ugel, Stefano; Sasso, Maria Stella; Qualls, Joseph E; Kratochvill, Franz; Zanovello, Paola; Molon, Barbara; Ries, Carola H; Runza, Valeria; Hoves, Sabine; Bilocq, Amélie M; Bindea, Gabriela; Mazza, Emilia M C; Bicciato, Silvio; Galon, Jérôme; Murray, Peter J; Bronte, Vincenzo

    2016-09-12

    Effective cancer immunotherapy requires overcoming immunosuppressive tumor microenvironments. We found that local nitric oxide (NO) production by tumor-infiltrating myeloid cells is important for adoptively transferred CD8(+) cytotoxic T cells to destroy tumors. These myeloid cells are phenotypically similar to inducible nitric oxide synthase (NOS2)- and tumor necrosis factor (TNF)-producing dendritic cells (DC), or Tip-DCs. Depletion of immunosuppressive, colony stimulating factor 1 receptor (CSF-1R)-dependent arginase 1(+) myeloid cells enhanced NO-dependent tumor killing. Tumor elimination via NOS2 required the CD40-CD40L pathway. We also uncovered a strong correlation between survival of colorectal cancer patients and NOS2, CD40, and TNF expression in their tumors. Our results identify a network of pro-tumor factors that can be targeted to boost cancer immunotherapies. PMID:27622331

  20. Increased brain nitric oxide levels following ethanol administration.

    PubMed

    Finnerty, Niall; O'Riordan, Saidhbhe L; Klamer, Daniel; Lowry, John; Pålsson, Erik

    2015-05-01

    Nitric oxide is a ubiquitous messenger molecule, which at elevated concentrations has been implicated in the pathogenesis of several neurological disorders. Its role in oxidative stress, attributed in particular to the formation of peroxynitrite, proceeds through its high affinity for the superoxide radical. Alcoholism has recently been associated with the induction of oxidative stress, which is generally defined as a shift in equilibrium between pro-oxidant and anti-oxidant species in the direction of the former. Furthermore, its primary metabolite acetaldehyde, has been extensively associated with oxidative damage related toxic effects following alcohol ingestion. The principal objective of this study was the application of long term in vivo electrochemistry (LIVE) to investigate the effect of ethanol (0.125, 0.5 and 2.0 g kg(-1)) and acetaldehyde (12.5, 50 and 200 mg kg(-1)) on NO levels in the nucleus accumbens of freely moving rats. Systemic administrations of ethanol and acetaldehyde resulted in a dose-dependent increases in NO levels, albeit with very differing time courses. Subsequent to this the effect on accumbal NO levels, of subjecting the animal to different drug combinations, was also elucidated. The nitric oxide synthase inhibitor L-NAME (20 mg kg(-1)) and acetaldehyde sequestering agent D-penicillamine (50 mg kg(-1)) both attenuated the increase in NO levels following ethanol (1 g kg(-1)) administration. Conversely, the alcohol dehydrogenase inhibitor 4-methylpyrazole (25 mg kg(-1)) and catalase inhibitor sodium azide (10 mg kg(-1)) potentiated the increase in NO levels following ethanol administration. Finally, dual inhibition of aldehyde dehydrogenase and catalase by cyanamide (25 mg kg(-1)) caused an attenuation of ethanol effects on NO levels. Taken together these data highlight a robust increase in brain NO levels following systemic alcohol administration which is dependent on NO synthase activity and may involve both alcohol- and acetaldehyde

  1. Role of nitric oxide and mechanisms involved in cerebral injury after subarachnoid hemorrhage: is nitric oxide a possible answer to cerebral vasospasm?

    PubMed

    Crobeddu, Emanuela; Pilloni, Giulia; Tardivo, Valentina; Fontanella, Marco M; Panciani, Pier P; Spena, Giannantonio; Fornaro, Riccardo; Altieri, Roberto; Agnoletti, Alessandro; Ajello, Marco; Zenga, Francesco; Ducati, Alessandro; Garbossa, Diego

    2016-09-01

    Cerebral vasospasm represents the most critical event that could occur after subarachnoid hemorrhage (SAH). Therapy is only partially effective because cerebral arterial constriction is not fully understood yet. One of the most important biological messenger associated to SAH is nitric oxide (NO), that is considered local regulator of cerebral blood flow. Different nitric oxide synthase (NOS) forms play a role in different biological processes, one of which is to link neuronal activity to blood flow in cerebral cortex. We performed a reassessment of the literature to summarize the role of NO as the main inflammatory pathway activated after SAH to clarify its importance for treatment of vasospasm.

  2. LPS-Induced Formation of Immunoproteasomes: TNF-α and Nitric Oxide Production are Regulated by Altered Composition of Proteasome-Active Sites

    PubMed Central

    Reis, Julia; Guan, Xiu Qin; Kisselev, Alexei F.; Papasian, Christopher J.; Qureshi, Asaf A.; Morrison, David C.; Van Way, Charles W.; Vogel, Stefanie N.

    2011-01-01

    Stimulation of mouse macrophages with LPS leads to tumor necrosis factor (TNF-α) secretion and nitric oxide (NO) release at different times through independent signaling pathways. While the precise regulatory mechanisms responsible for these distinct phenotypic responses have not been fully delineated, results of our recent studies strongly implicate the cellular cytoplasmic ubiquitin–proteasome pathway as a key regulator of LPS-induced macrophage inflammatory responses. Our objective in this study was to define the relative contribution of specific proteasomal active-sites in induction of TNF-α and NO after LPS treatment of RAW 264.7 macrophages using selective inhibitors of these active sites. Our data provide evidence that LPS stimulation of mouse macrophages triggers a selective increase in the levels of gene and protein expression of the immunoproteasomes, resulting in a modulation of specific functional activities of the proteasome and a corresponding increase in NO production as compared to untreated controls. These findings suggest the LPS-dependent induction of immunoproteasome. In contrast, we also demonstrate that TNF-α expression is primarily dependent on both the chymotrypsin- and the trypsin-like activities of X, Y, Z subunits of the proteasome. Proteasome-associated post-acidic activity alone also contributes to LPS-induced expression of TNF-α. Taken together; our results indicate that LPS-induced TNF-α in macrophages is differentially regulated by each of the three proteasome activities. Since addition of proteasome inhibitors to mouse macrophages profoundly affects the degradation of proteins involved in signal transduction, we conclude that proteasome-specific degradation of several signaling proteins is likely involved in differential regulation of LPS-dependent secretion of proinflammatory mediators. PMID:21455682

  3. Properties of immature myeloid progenitors with nitric-oxide-dependent immunosuppressive activity isolated from bone marrow of tumor-free mice.

    PubMed

    Forghani, Parvin; Harris, Wayne; Giver, Cynthia R; Mirshafiey, Abbas; Galipeau, Jacques; Waller, Edmund K

    2013-01-01

    Myeloid derived suppressor cells (MDSCs) from tumor-bearing mice are important negative regulators of anti-cancer immune responses, but the role for immature myeloid cells (IMCs) in non-tumor-bearing mice in the regulation of immune responses are poorly described. We studied the immune-suppressive activity of IMCs from the bone marrow (BM) of C57Bl/6 mice and the mechanism(s) by which they inhibit T-cell activation and proliferation. IMCs, isolated from BM by high-speed FACS, inhibited mitogen-induced proliferation of CD4(+) and CD8(+) T-cells in vitro. Cell-to-cell contact of T-cells with viable IMCs was required for suppression. Neither neutralizing antibodies to TGFβ1, nor genetic disruption of indolamine 2,3-dioxygenase, abrogated IMC-mediated suppressive activity. In contrast, suppression of T-cell proliferation was absent in cultures containing IMCs from interferon-γ (IFN-γ) receptor KO mice or T-cells from IFN-γ KO mice (on the C57Bl/6 background). The addition of NO inhibitors to co-cultures of T-cells and IMC significantly reduced the suppressive activity of IMCs. IFN-γ signaling between T-cells and IMCs induced paracrine Nitric Oxide (NO) release in culture, and the degree of inhibition of T-cell proliferation was proportional to NO levels. The suppressive activity of IMCs from the bone marrow of tumor-free mice was comparable with MDSCs from BALB/c bearing mice 4T1 mammary tumors. These results indicate that IMCs have a role in regulating T-cell activation and proliferation in the BM microenvironment.

  4. 21 CFR 862.3080 - Breath nitric oxide test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... fractional nitric oxide concentration in expired breath aids in evaluating an asthma patient's response to anti-inflammatory therapy, as an adjunct to established clinical and laboratory assessments of...

  5. 21 CFR 862.3080 - Breath nitric oxide test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... fractional nitric oxide concentration in expired breath aids in evaluating an asthma patient's response to anti-inflammatory therapy, as an adjunct to established clinical and laboratory assessments of...

  6. 21 CFR 862.3080 - Breath nitric oxide test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... fractional nitric oxide concentration in expired breath aids in evaluating an asthma patient's response to anti-inflammatory therapy, as an adjunct to established clinical and laboratory assessments of...

  7. 21 CFR 862.3080 - Breath nitric oxide test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... fractional nitric oxide concentration in expired breath aids in evaluating an asthma patient's response to anti-inflammatory therapy, as an adjunct to established clinical and laboratory assessments of...

  8. 21 CFR 862.3080 - Breath nitric oxide test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... fractional nitric oxide concentration in expired breath aids in evaluating an asthma patient's response to anti-inflammatory therapy, as an adjunct to established clinical and laboratory assessments of...

  9. Inducible Nitric Oxide Synthase Expression in Human Colorectal Cancer

    PubMed Central

    Cianchi, Fabio; Cortesini, Camillo; Fantappiè, Ornella; Messerini, Luca; Schiavone, Nicola; Vannacci, Alfredo; Nistri, Silvia; Sardi, Iacopo; Baroni, Gianna; Marzocca, Cosimo; Perna, Federico; Mazzanti, Roberto; Bechi, Paolo; Masini, Emanuela

    2003-01-01

    To investigate the potential involvement of the nitric oxide (NO) pathway in colorectal carcinogenesis, we correlated the expression and the activity of inducible nitric oxide synthase (iNOS) with the degree of tumor angiogenesis in human colorectal cancer. Tumor samples and adjacent normal mucosa were obtained from 46 surgical specimens. Immunohistochemical expression of iNOS, vascular endothelial growth factor (VEGF), and CD31 was analyzed on paraffin-embedded tissue sections. iNOS activity and cyclic GMP levels were assessed by specific biochemical assays. iNOS protein expression was determined by Western blot analysis. iNOS and VEGF mRNA levels were evaluated using Northern blot analysis. Both iNOS and VEGF expressions correlated significantly with intratumor microvessel density (rs = 0.31, P = 0.02 and rs = 0.67, P < 0.0001, respectively). A significant correlation was also found between iNOS and VEGF expression (P = 0.001). iNOS activity and cyclic GMP production were significantly higher in the cancer specimens than in the normal mucosa (P < 0.0001 and P < 0.0001, respectively), as well as in metastatic tumors than in nonmetastatic ones (P = 0.002 and P = 0.04, respectively). Western and Northern blot analyses confirmed the up-regulation of the iNOS protein and gene in the tumor specimens as compared with normal mucosa. NO seems to play a role in colorectal cancer growth by promoting tumor angiogenesis. PMID:12598314

  10. Measurements of nitric oxide after a nuclear burst

    NASA Technical Reports Server (NTRS)

    Mcghan, M.; Shaw, A.; Megill, L. R.; Sedlacek, W.; Guthals, P. R.; Fowler, M. M.

    1981-01-01

    Measurements of ozone and nitric oxide in a nuclear cloud 7 days after the explosion are reported. No measurable increase above ambient density of either ozone or nitric oxide was found. Results from a chemistry model of the cloud do not agree with the measurement unless 'nonstandard' assumptions are made with regard to the operating chemical processes. A number of possible explanations of the results are discussed.

  11. Nitric oxide and cancer: a review

    PubMed Central

    2013-01-01

    Nitric oxide (NO), is a ubiquitous, water soluble, free radical gas, which plays key role in various physiological as well as pathological processes. Over past decades, NO has emerged as a molecule of interest in carcinogenesis and tumor growth progression. However, there is considerable controversy and confusion in understanding its role in cancer biology. It is said to have both tumoricidal as well as tumor promoting effects which depend on its timing, location, and concentration. NO has been suggested to modulate different cancer-related events including angiogenesis, apoptosis, cell cycle, invasion, and metastasis. On the other hand, it is also emerging as a potential anti-oncogenic agent. Strategies for manipulating in vivo production and exogenous delivery of this molecule for therapeutic gain are being investigated. However, further validation and experimental/clinical trials are required for development of novel strategies based on NO for cancer treatment and prevention. This review discusses the range of actions of NO in cancer by performing an online MEDLINE search using relevant search terms and a review of the literature. Various mechanisms by which NO acts in different cancers such as breast, cervical, gastric,colorectal, and head and neck cancers are addressed. It also offers an insight into the dichotomous nature of NO and discusses its novel therapeutic applications for cancer prevention and treatment. PMID:23718886

  12. Nitric oxide and oral cancer: a review.

    PubMed

    Korde Choudhari, Sheetal; Sridharan, Gokul; Gadbail, Amol; Poornima, V

    2012-06-01

    Nitric oxide (NO), a short-lived, endogenously produced gas, plays key role in various physiological as well as pathological processes. NO-inducing cell signaling events within the cell producing it and the diffusibility of it in other cells have led to the discovery of various physiological functions of NO including vasodilation, respiration, cell migration, immune response and apoptosis. On the other hand, excessive and unregulated NO synthesis has been implicated in many pathophysiological conditions including cancer. Research on NO, during the past few years is one of the growing areas in cancer biology. The high incidence of oral cancer and precancer has been linked with habits of tobacco chewing and smoking and NO has been said as the "messenger of death" in tobacco related diseases. NO seems to play a part in various stages of carcinogenesis from initiation to progression. However, there is considerable controversy and confusion in understanding its role in cancer biology. It is said to have both, tumoricidal as well as tumor promoting effects and these depend on its timing, location and concentration. Further, NO has also been shown to have antitumor, chemopreventive and therapeutic abilities. Here is an overview in which efforts are made to understand the role of this molecule in oral carcinogenesis. PMID:22356896

  13. Dietary Nitrate, Nitric Oxide, and Cardiovascular Health.

    PubMed

    Bondonno, Catherine P; Croft, Kevin D; Hodgson, Jonathan M

    2016-09-01

    Emerging evidence strongly suggests that dietary nitrate, derived in the diet primarily from vegetables, could contribute to cardiovascular health via effects on nitric oxide (NO) status. NO plays an essential role in cardiovascular health. It is produced via the classical L-arginine-NO-synthase pathway and the recently discovered enterosalivary nitrate-nitrite-NO pathway. The discovery of this alternate pathway has highlighted dietary nitrate as a candidate for the cardioprotective effect of a diet rich in fruit and vegetables. Clinical trials with dietary nitrate have observed improvements in blood pressure, endothelial function, ischemia-reperfusion injury, arterial stiffness, platelet function, and exercise performance with a concomitant augmentation of markers of NO status. While these results are indicative of cardiovascular benefits with dietary nitrate intake, there is still a lingering concern about nitrate in relation to methemoglobinemia, cancer, and cardiovascular disease. It is the purpose of this review to present an overview of NO and its critical role in cardiovascular health; to detail the observed vascular benefits of dietary nitrate intake through effects on NO status as well as to discuss the controversy surrounding the possible toxic effects of nitrate.

  14. Hemoglobin: A Nitric-Oxide Dioxygenase

    PubMed Central

    Gardner, Paul R.

    2012-01-01

    Members of the hemoglobin superfamily efficiently catalyze nitric-oxide dioxygenation, and when paired with native electron donors, function as NO dioxygenases (NODs). Indeed, the NOD function has emerged as a more common and ancient function than the well-known role in O2 transport-storage. Novel hemoglobins possessing a NOD function continue to be discovered in diverse life forms. Unique hemoglobin structures evolved, in part, for catalysis with different electron donors. The mechanism of NOD catalysis by representative single domain hemoglobins and multidomain flavohemoglobin occurs through a multistep mechanism involving O2 migration to the heme pocket, O2 binding-reduction, NO migration, radical-radical coupling, O-atom rearrangement, nitrate release, and heme iron re-reduction. Unraveling the physiological functions of multiple NODs with varying expression in organisms and the complexity of NO as both a poison and signaling molecule remain grand challenges for the NO field. NOD knockout organisms and cells expressing recombinant NODs are helping to advance our understanding of NO actions in microbial infection, plant senescence, cancer, mitochondrial function, iron metabolism, and tissue O2 homeostasis. NOD inhibitors are being pursued for therapeutic applications as antibiotics and antitumor agents. Transgenic NOD-expressing plants, fish, algae, and microbes are being developed for agriculture, aquaculture, and industry. PMID:24278729

  15. Nitric oxide modulates sensitivity to ABA.

    PubMed

    Lozano-Juste, Jorge; León, José

    2010-03-01

    Nitric oxide (NO) is a gas with crucial signaling functions in plant defense and development. As demonstrated by generating a triple nia1nia2noa1-2 mutant with extremely low levels of NO (February 2010 issue of Plant Physiology), NO is synthesized in plants through mainly two different pathways involving nitrate reductase (NR/NIA) and NO Associated 1 (AtNOA1) proteins. Depletion of basal NO levels leads to a priming of ABA-triggered responses that causes hypersensitivity to this hormone and results in enhanced seed dormancy and decreased seed germination and seedling establishment in the triple mutant. NO produced under non-stressed conditions represses inhibition of seed developmental transitions by ABA. Moreover, NO plays a positive role in post-germinative vegetative development and also exerts a critical control of ABA-related functions on stomata closure. The triple nia1nia2noa1-2 mutant is hypersensitive to ABA in stomatal closure thus resulting in a extreme phenotype of resistance to drought. In the light of the recent discovery of PYR/PYL/RCAR as a family of potential ABA receptors, regulation of ABA sensitivity by NO may be exerted either directly on ABA receptors or on downstream signaling components; both two aspects that deserve our present and future attention.

  16. Nitric oxide production in critically ill patients.

    PubMed Central

    Wong, H R; Carcillo, J A; Burckart, G; Kaplan, S S

    1996-01-01

    OBJECTIVE: To measure serum nitrite and nitrate levels in critically ill children as indicators of endogenous nitric oxide (NO) production. HYPOTHESIS: Endogenous NO production is increased in children with conditions characterised by immune stimulation. DESIGN: Prospective descriptive study in a multidisciplinary paediatric intensive care unit. PATIENTS: 137 consecutive critically ill children with a variety of clinical conditions. INTERVENTIONS: Using a rapid microtitre plate technique, daily serum nitrite and nitrate levels were measured from serum samples that remained in the clinical laboratory after daily routine phlebotomy. Clinical and laboratory information was also gathered daily for each patient. RESULTS: The maximum serum nitrite plus nitrate levels (microM) reached by children with infection (41.8 (SD 18.1)), sepsis syndrome (85.1 (39.9)), shock without sepsis (36.4 (19.1)), transplantation alone (61.0 (43.4)), transplantation with sepsis (200.7 (150.5)), or rejection (161.7 (70.4)), were higher than in controls (18.1 (9.3)). In the absence of exogenous NO donors, levels greater than 80 microM were reached only in children with the sepsis syndrome, organ transplantation, or acute rejection. CONCLUSIONS: Increased endogenous NO production occurs in children with clinical conditions associated with immune stimulation. Further investigation is warranted to determine the value of this simple and rapid test as a clinically useful diagnostic tool and therapeutic monitor in the evaluation of children at risk for the sepsis syndrome or acute allograft rejection. PMID:8758122

  17. The Adaptogens Rhodiola and Schizandra Modify the Response to Immobilization Stress in Rabbits by Suppressing the Increase of Phosphorylated Stress-activated Protein Kinase, Nitric Oxide and Cortisol

    PubMed Central

    Panossian, Alexander; Hambardzumyan, Marina; Hovhanissyan, Areg; Wikman, Georg

    2007-01-01

    Adaptogens possess anti-fatigue and anti-stress activities that can increase mental and physical working performance against a background of fatigue or stress. The aim of the present study was to ascertain which mediators of stress response are significantly involved in the mechanisms of action of adaptogens, and to determine their relevance as biochemical markers for evaluating anti-stress effects in rabbits subjected to restraint stress. Blood levels of stress-activated protein kinase (SAPK/JNK), the phosphorylated kinase p-SAPK/p-JNK, nitric oxide (NO), cortisol, testosterone, prostaglandin E2, leukotriene B4 and thromboxane B2 were determined in groups of animals prior to daily oral administration of placebo, rhodioloside or extracts of Eleutherococcus senticosus, Schizandra chinensis, Rhodiola rosea, Bryonia alba and Panax ginseng over a 7 day period. Ten minutes after the final treatment, animals were immobilized for 2 hours and blood levels of the markers re-determined. In the placebo group, only p-SAPK/p-JNK, NO and cortisol were increased significantly (by 200–300% cf basal levels) following restraint stress, whilst in animals that had received multiple doses of adaptogens/stress-protectors, the levels of NO and cortisol remained practically unchanged after acute stress. Rhodioloside and extracts of S. chinensis and R. rosea were the most active inhibitors of stress-induced p-SAPK/p-JNK. E. senticosus, B. alba and P. ginseng exerted little effect on p-SAPK/p-JNK levels. It is suggested that the inhibitory effects of R. rosea and S. chinensis on p-SAPK/p-JNK activation may be associated with their antidepressant activity as well as their positive effects on mental performance under stress. PMID:21901061

  18. Microglial activation and beta -amyloid deposit reduction caused by a nitric oxide-releasing nonsteroidal anti-inflammatory drug in amyloid precursor protein plus presenilin-1 transgenic mice.

    PubMed

    Jantzen, Paul T; Connor, Karen E; DiCarlo, Giovanni; Wenk, Gary L; Wallace, John L; Rojiani, Amyn M; Coppola, Domenico; Morgan, Dave; Gordon, Marcia N

    2002-03-15

    3-4-(2-Fluoro-alpha-methyl-[1,1'-biphenyl]-4-acetyloxy)-3-methoxyphenyl]-2-propenoic acid 4-nitrooxy butyl ester (NCX-2216), a nitric oxide (NO)-releasing derivative of the cyclooxygenase-1-preferring nonsteroidal anti-inflammatory drug (NSAID) flurbiprofen, dramatically reduced both beta-amyloid (Abeta) loads and Congo red staining in doubly transgenic (Tg) amyloid precursor protein plus presenilin-1 mice when administered at 375 ppm in diet between 7 and 12 months of age. This reduction was associated with a dramatic increase in the number of microglia expressing major histocompatibility complex-II antigen, a marker for microglial activation. In contrast, ibuprofen at 375 ppm in diet caused modest reductions in Abeta load but not Congo red staining, suggesting that the effects of this nonselective NSAID were restricted primarily to nonfibrillar deposits. We detected no effects of the cyclooxygenase-2-selective NSAID celecoxib at 175 ppm on amyloid deposition. In short-term studies of 12-month-old Tg mice, we found that the microglia-activating properties of NCX-2216 (7.5 mg small middle dot kg(-1) small middle dot d(-1), s.c.) were present after 2 weeks of treatment. Microglia were not activated by NCX-2216 in non-Tg mice lacking Abeta deposits, nor were microglia activated in Tg animals by flurbiprofen (5 mg small middle dot kg(-1) small middle dot d(-1)) alone. These data are consistent with the argument that activated microglia can clear Abeta deposits. We conclude that the NO-generating component of NCX-2216 confers biological actions that go beyond those of typical NSAIDs. In conclusion, NCX-2216 is more efficacious than ibuprofen or celecoxib in clearing Abeta deposits from the brains of Tg mice, implying potential benefit in the treatment of Alzheimer's dementia.

  19. Soluble factors released by Toxoplasma gondii-infected astrocytes down-modulate nitric oxide production by gamma interferon-activated microglia and prevent neuronal degeneration.

    PubMed

    Rozenfeld, Claudia; Martinez, Rodrigo; Figueiredo, Rodrigo T; Bozza, Marcelo T; Lima, Flávia R S; Pires, Ana Lúcia; Silva, Patrícia M; Bonomo, Adriana; Lannes-Vieira, Joseli; De Souza, Wanderley; Moura-Neto, Vivaldo

    2003-04-01

    The maintenance of a benign chronic Toxoplasma gondii infection is mainly dependent on the persistent presence of gamma interferon (IFN-gamma) in the central nervous system (CNS). However, IFN-gamma-activated microglia are paradoxically involved in parasitism control and in tissue damage during a broad range of CNS pathologies. In this way, nitric oxide (NO), the main toxic metabolite produced by IFN-gamma-activated microglia, may cause neuronal injury during T. gondii infection. Despite the potential NO toxicity, neurodegeneration is not a common finding during chronic T. gondii infection. In this work, we describe a significant down-modulation of NO production by IFN-gamma-activated microglia in the presence of conditioned medium of T. gondii-infected astrocytes (CMi). The inhibition of NO production was paralleled with recovery of neurite outgrowth when neurons were cocultured with IFN-gamma-activated microglia in the presence of CMi. Moreover, the modulation of NO secretion and the neuroprotective effect were shown to be dependent on prostaglandin E(2) (PGE(2)) production by T. gondii-infected astrocytes and autocrine secretion of interleukin-10 (IL-10) by microglia. These events were partially eliminated when infected astrocytes were treated with aspirin and cocultures were treated with anti-IL-10 neutralizing antibodies and RP-8-Br cyclic AMP (cAMP), a protein kinase A inhibitor. Further, the modulatory effects of CMi were mimicked by the presence of exogenous PGE(2) and by forskolin, an adenylate cyclase activator. Altogether, these data point to a T. gondii-triggered regulatory mechanism involving PGE(2) secretion by astrocytes and cAMP-dependent IL-10 secretion by microglia. This may reduce host tissue inflammation, thus avoiding neuron damage during an established Th1 protective immune response. PMID:12654825

  20. Methoxychlor-induced inducible nitric oxide synthase and proinflammatory cytokines expression in macrophages via NF-kappaB, ERK, and p38 mitogen-activated protein kinases.

    PubMed

    Kim, Ji Young; Oh, Kyo Nyeo; Han, Eun Hee; Kim, Dong Hee; Jeong, Tae Cheon; Lee, Eung Seok; Jeong, Hye Gwang

    2005-08-12

    Methoxychlor (MXC) is a pesticide that was developed as a replacement for dichlorodiphenyltrichloroethane. The influence of MXC on cytokine production or the functions of macrophages is unclear. This study examined the effects of MXC on the production of nitric oxide (NO) and the proinflammatory cytokines (IL-1beta, IL-6, and TNF-alpha), and analyzed the molecular mechanism in mouse macrophages. The addition of MXC to macrophages induced the production of NO and proinflammatory cytokines and expression levels of these genes in a dose-dependent manner. The NF-kappaB sites were identified in the promoter of the iNOS and proinflammatory cytokines genes. The transient expression and electrophoretic mobility shift assays revealed that the NF-kappaB transcription factor mediated the MXC-induced increase in the iNOS and proinflammatory cytokines expression levels. In addition, MXC induced the rapid phosphorylation of the ERK1/2 and p38 MAPK. This demonstrates that MXC stimulates the production of NO and proinflammatory cytokines and can up-regulate the expression levels of these genes via NF-kappaB transactivation and ERK1/2 and p38 MAPK phosphorylation. Overall, this study provides evidence showing that MXC has inflammatory potential that is previously unrecognized immunomodulating activity.

  1. Nitric oxide in adaptation to altitude

    PubMed Central

    Laskowski, Daniel; Erzurum, Serpil C.

    2012-01-01

    This review summarizes published information on levels of nitric oxide gas (NO) in the lungs and NO-derived liquid phase molecules in the acclimatization of visitors newly arrived at altitudes of 2500m or more and adaptation of populations whose ancestors arrived thousands of years ago. Studies of acutely exposed visitors to high altitude focus on the first 24–48 hours with just a few extending to days or weeks. Among healthy visitors, NO levels in the lung, plasma and/or red blood cells fell within three hours, but then returned toward baseline or slightly higher by 48 hours, and increased above baseline by 5 days. Among visitors ill with high-altitude pulmonary edema at the time of the study or in the past, NO levels were lower than their healthy counterparts. As for highland populations, Tibetans had NO levels in the lung, plasma and red blood cells that were at least double and in some cases orders of magnitude greater than other populations regardless of altitude. Red blood cell associated nitrogen oxides were more than two hundred times higher. Other highland populations had generally higher levels although not to the degree showed by Tibetans. Overall, responses of those acclimatized and those presumed to be adapted are in the same direction although the Tibetans have much larger responses. Missing are long-term data on lowlanders at altitude showing how similar they become to the Tibetan phenotype. Also missing are data on Tibetans at low altitude to see the extent to which their phenotype is a response to the immediate environment or expressed constitutively. The mechanisms causing the visitors’ and the Tibetans’ high levels of NO and NO-derived molecules at altitude remain unknown. Limited data suggest processes including hypoxic upregulation of NO synthase gene expression, hemoglobin-NO reactions and genetic variation. Gains in understanding will require integrating appropriate methods and measurement techniques with indicators of adaptive function

  2. Nitric oxide and iron modulate heme oxygenase activity as a long distance signaling response to salt stress in sunflower seedling cotyledons.

    PubMed

    Singh, Neha; Bhatla, Satish C

    2016-02-29

    Nitric oxide is a significant component of iron signaling in plants. Heme is one of the iron sensors in plants. Free heme is highly toxic and can cause cell damage as it catalyzes the formation of reactive oxygen species (ROS). Its catabolism is carried out by heme oxygenase (HOs; EC 1.14.99.3) which uses heme both as a prosthetic group and as a substrate. Two significant events, which accompany adaptation to salt stress in sunflower seedlings, are accumulation of ROS and enhanced production of nitric oxide (NO) in roots and cotyledons. Present investigations on the immunolocalization of heme oxygenase distribution in sunflower seedling cotyledons by confocal laser scanning microscopic (CLSM) imaging provide new information on the differential spatial distribution of the inducible form of HO (HO-1) as a long distance in response to NaCl stress. The enzyme is abundantly distributed in the specialized cells around the secretory canals (SCs) in seedling cotyledons. Abundance of tyrosine nitrated proteins has also been observed in the specialized cells around the secretory canals in cotyledons derived from salt stressed seedlings. The spatial distribution of tyrosine nitrated proteins and HO-1 expression further correlates with the abundance of mitochondria in these cells. Present findings, thus, highlight a link among distribution of HO-1 expression, abundance of tyrosine nitrated proteins and mitochondria in specialized cells around the secretory canal as a long distance mechanism of salt stress tolerance in sunflower seedlings. Enhanced spatial distribution of HO-1 in response to NaCl stress in seedling cotyledons is in congruence with the observed increase in specific activity of HO-1 in NaCl stressed conditions. The enzyme activity is further enhanced by hemin (HO-1 inducer) both in the absence or presence of NaCl stress and inhibited by zinc protoporphyrin. Western blot analysis of cotyledon homogenates using anti-HO-1 polyclonal antibody shows one major band (29

  3. Evaluation of Salivary Nitric Oxide Levels in Smokers, Tobacco Chewers and Patients with Oral Lichenoid Reactions

    PubMed Central

    Jose, Joy Idiculla; Sivapathasundharam, B.; Sabarinath, B.

    2016-01-01

    Introduction Nitric oxide (NO), a free radical, acts as a signalling molecule affecting numerous physiological and pathological processes. Role of nitric oxide as a mediator in tobacco related habits and the resultant oral lichenoid reactions was assessed. Aim The aim of the study is to evaluate and compare the salivary nitric oxide levels in normal patients with that of smokers, tobacco chewers and patients with oral lichenoid reactions. Materials and Methods One hundred and twenty patients were enrolled in the study which included 30 healthy patients without any chronic inflammatory lesion and habit as controls (group I), 30 smokers without the habit of tobacco/betel nut chewing and any oral lesion (group II), 30 tobacco chewers without the habit of smoking and any oral lesion (group III) and 30 histologically confirmed cases of oral lichenoid reaction with the habit of tobacco usage (group IV). Saliva from these patients was collected and the nitrite concentration was assessed. Results Our results concluded that there was highly significant increase in the nitric oxide levels in smokers, tobacco chewers and patients with oral lichenoid reactions compared to that of controls. Also, there was a significant increase in nitric oxide levels in patients with smoking associated oral lichenoid reactions in comparison with smokers and in patients with lichenoid reactions associated with tobacco chewing in comparison with tobacco chewers. Conclusion Estimation of salivary nitric oxide levels is a simple, non-invasive procedure and could be analysed to suggest the role of nitric oxide in the pathogenesis of these lesions. The increased activity of the enzyme may indicate that nitric oxide has a pathophysiological role in these lesions. PMID:26894179

  4. The poly-γ-d-glutamic acid capsule surrogate of the Bacillus anthracis capsule induces nitric oxide production via the platelet activating factor receptor signaling pathway.

    PubMed

    Lee, Hae-Ri; Jeon, Jun Ho; Park, Ok-Kyu; Chun, Jeong-Hoon; Park, Jungchan; Rhie, Gi-Eun

    2015-12-01

    The poly-γ-d-glutamic acid (PGA) capsule, a major virulence factor of Bacillus anthracis, confers protection of the bacillus from phagocytosis and allows its unimpeded growth in the host. PGA capsules released from B. anthracis are associated with lethal toxin in the blood of experimentally infected animals and enhance the cytotoxic effect of lethal toxin on macrophages. In addition, PGA capsule itself activates macrophages and dendritic cells to produce proinflammatory cytokine such as IL-1β, indicating multiple roles of PGA capsule in anthrax pathogenesis. Here we report that PGA capsule of Bacillus licheniformis, a surrogate of B. anthracis capsule, induces production of nitric oxide (NO) in RAW264.7 cells and bone marrow-derived macrophages. NO production was induced by PGA in a dose-dependent manner and was markedly reduced by inhibitors of inducible NO synthase (iNOS), suggesting iNOS-dependent production of NO. Induction of NO production by PGA was not observed in macrophages from TLR2-deficient mice and was also substantially inhibited in RAW264.7 cells by pretreatment of TLR2 blocking antibody. Subsequently, the downstream signaling events such as ERK, JNK and p38 of MAPK pathways as well as NF-κB activation were required for PGA-induced NO production. In addition, the induced NO production was significantly suppressed by treatment with antagonists of platelet activating factor receptor (PAFR) or PAFR siRNA, and mediated through PAFR/Jak2/STAT-1 signaling pathway. These findings suggest that PGA capsule induces NO production in macrophages by triggering both TLR2 and PAFR signaling pathways which lead to activation of NF-kB and STAT-1, respectively.

  5. The larvicidal activity of Agave sisalana against L4 larvae of Aedes aegypti is mediated by internal necrosis and inhibition of nitric oxide production.

    PubMed

    Nunes, Fabiola C; Leite, Jacqueline A; Oliveira, Louise H G; Sousa, Patrícia A P S; Menezes, Márcio C; Moraes, João P S; Mascarenhas, Sandra R; Braga, Valdir A

    2015-02-01

    Dengue is a viral disease that affects about 50 million people per year around the world. The aim of this study was to investigate the larvicidal activity of Agave sisalana crude extract in order to develop a new insecticide against Aedes aegypti. In larvicidal activity assays, fourth-stage Ae. aegypti larvae were exposed to different concentrations of A. sisalana crude extract for 3, 6, 12, and 24 h for determining the LC50. Next, we explored its cytotoxic activity by flow cytometry. Furthermore, histological alterations were confirmed by histopathological analysis, and the nitric oxide (NO) production by hemocytes was checked after different periods of exposure to A. sisalana crude extract. The LC50 was 4.5 ± 0.07 mg/mL. In addition, flow cytometry revealed an increase of cellular necrosis (21 and 16.5 % after 12 and 24 h, respectively) in larvae that were exposed to A. sisalana crude extract. The histological analysis revealed cell lysis and destruction of the peritrophic membrane. Furthermore, there was a reduction in the concentration of NO in the hemolymph from larvae exposed to A. sisalana crude extract after 3, 6, and 24 h (5.3 ± 4.3 vs. 22.7 ± 5.2 μM, 4.3 ± 5.5 vs. 25.4 ± 6.6 μM, and 6 ± 1.7 vs. 37.1 ± 7.8 μM, respectively). Our findings show that A. sisalana crude extract constitutes an effective larvicidal agent against Ae. aegypti larvae due to its necrotizing activity in hemocytes and inhibition of the NO production. PMID:25395257

  6. Nitric Oxide from IFNγ-Primed Macrophages Modulates the Antimicrobial Activity of β-Lactams against the Intracellular Pathogens Burkholderia pseudomallei and Nontyphoidal Salmonella

    PubMed Central

    Jones-Carson, Jessica; Zweifel, Adrienne E.; Tapscott, Timothy; Austin, Chad; Brown, Joseph M.; Jones, Kenneth L.; Voskuil, Martin I.; Vázquez-Torres, Andrés

    2014-01-01

    Our investigations show that nonlethal concentrations of nitric oxide (NO) abrogate the antibiotic activity of β-lactam antibiotics against Burkholderia pseudomallei, Escherichia coli and nontyphoidal Salmonella enterica serovar Typhimurium. NO protects B. pseudomallei already exposed to β-lactams, suggesting that this diatomic radical tolerizes bacteria against the antimicrobial activity of this important class of antibiotics. The concentrations of NO that elicit antibiotic tolerance repress consumption of oxygen (O2), while stimulating hydrogen peroxide (H2O2) synthesis. Transposon insertions in genes encoding cytochrome c oxidase-related functions and molybdenum assimilation confer B. pseudomallei a selective advantage against the antimicrobial activity of the β-lactam antibiotic imipenem. Cumulatively, these data support a model by which NO induces antibiotic tolerance through the inhibition of the electron transport chain, rather than by potentiating antioxidant defenses as previously proposed. Accordingly, pharmacological inhibition of terminal oxidases and nitrate reductases tolerizes aerobic and anaerobic bacteria to β-lactams. The degree of NO-induced β-lactam antibiotic tolerance seems to be inversely proportional to the proton motive force (PMF), and thus the dissipation of ΔH+ and ΔΨ electrochemical gradients of the PMF prevents β-lactam-mediated killing. According to this model, NO generated by IFNγ-primed macrophages protects intracellular Salmonella against imipenem. On the other hand, sublethal concentrations of imipenem potentiate the killing of B. pseudomallei by NO generated enzymatically from IFNγ-primed macrophages. Our investigations indicate that NO modulates the antimicrobial activity of β-lactam antibiotics. PMID:25121731

  7. Nitric oxide synthase inhibition prevents activity-induced calcineurin-NFATc1 signalling and fast-to-slow skeletal muscle fibre type conversions.

    PubMed

    Martins, Karen J B; St-Louis, Mathieu; Murdoch, Gordon K; MacLean, Ian M; McDonald, Pamela; Dixon, Walter T; Putman, Charles T; Michel, Robin N

    2012-03-15

    The calcineurin–NFAT (nuclear factor of activated T-cells) signalling pathway is involved in the regulation of activity-dependent skeletal muscle myosin heavy chain (MHC) isoform type expression. Emerging evidence indicates that nitric oxide (NO) may play a critical role in this regulatory pathway. Thus, the purpose of this study was to investigate the role of NO in activity-induced calcineurin–NFATc1 signalling leading to skeletal muscle faster-to-slower fibre type transformations in vivo. Endogenous NO production was blocked by administering L-NAME (0.75 mg ml(−1)) in drinking water throughout 0, 1, 2, 5 or 10 days of chronic low-frequency stimulation (CLFS; 10 Hz, 12 h day(−1)) of rat fast-twitch muscles (L+Stim; n = 30) and outcomes were compared with control rats receiving only CLFS (Stim; n = 30). Western blot and immunofluorescence analyses revealed that CLFS induced an increase in NFATc1 dephosphorylation and nuclear localisation, sustained by glycogen synthase kinase (GSK)-3β phosphorylation in Stim, which were all abolished in L+Stim. Moreover, real-time RT-PCR revealed that CLFS induced an increased expression of MHC-I, -IIa and -IId(x) mRNAs in Stim that was abolished in L+Stim. SDS-PAGE and immunohistochemical analyses revealed that CLFS induced faster-to-slower MHC protein and fibre type transformations, respectively, within the fast fibre population of both Stim and L+Stim groups. The final fast type IIA to slow type I transformation, however, was prevented in L+Stim. It is concluded that NO regulates activity-induced MHC-based faster-to-slower fibre type transformations at the transcriptional level via inhibitory GSK-3β-induced facilitation of calcineurin–NFATc1 nuclear accumulation in vivo, whereas transformations within the fast fibre population may also involve translational control mechanisms independent of NO signalling.

  8. The larvicidal activity of Agave sisalana against L4 larvae of Aedes aegypti is mediated by internal necrosis and inhibition of nitric oxide production.

    PubMed

    Nunes, Fabiola C; Leite, Jacqueline A; Oliveira, Louise H G; Sousa, Patrícia A P S; Menezes, Márcio C; Moraes, João P S; Mascarenhas, Sandra R; Braga, Valdir A

    2015-02-01

    Dengue is a viral disease that affects about 50 million people per year around the world. The aim of this study was to investigate the larvicidal activity of Agave sisalana crude extract in order to develop a new insecticide against Aedes aegypti. In larvicidal activity assays, fourth-stage Ae. aegypti larvae were exposed to different concentrations of A. sisalana crude extract for 3, 6, 12, and 24 h for determining the LC50. Next, we explored its cytotoxic activity by flow cytometry. Furthermore, histological alterations were confirmed by histopathological analysis, and the nitric oxide (NO) production by hemocytes was checked after different periods of exposure to A. sisalana crude extract. The LC50 was 4.5 ± 0.07 mg/mL. In addition, flow cytometry revealed an increase of cellular necrosis (21 and 16.5 % after 12 and 24 h, respectively) in larvae that were exposed to A. sisalana crude extract. The histological analysis revealed cell lysis and destruction of the peritrophic membrane. Furthermore, there was a reduction in the concentration of NO in the hemolymph from larvae exposed to A. sisalana crude extract after 3, 6, and 24 h (5.3 ± 4.3 vs. 22.7 ± 5.2 μM, 4.3 ± 5.5 vs. 25.4 ± 6.6 μM, and 6 ± 1.7 vs. 37.1 ± 7.8 μM, respectively). Our findings show that A. sisalana crude extract constitutes an effective larvicidal agent against Ae. aegypti larvae due to its necrotizing activity in hemocytes and inhibition of the NO production.

  9. Post-ischaemic mild hypothermia inhibits apoptosis in the penumbral region by reducing neuronal nitric oxide synthase activity and thereby preventing endothelin-1-induced hydroxyl radical formation.

    PubMed

    Van Hemelrijck, An; Hachimi-Idrissi, Said; Sarre, Sophie; Ebinger, Guy; Michotte, Yvette

    2005-09-01

    Previously, we showed that treatment with resuscitative, post-ischaemic mild hypothermia (34 degrees C for 2 h) reduced apoptosis in the penumbra (cortex), but not in the core (striatum) of an endothelin-1 (Et-1)-induced focal cerebral infarct in the anaesthetized rat. Therefore, the purpose of this study was to investigate by which pathways resuscitative mild hypothermia exerts its neuroprotective effect in this model. The amino acids glutamate, serine, glutamine, alanine, taurine, arginine and the NO-related compound citrulline were sampled from the striatum and cortex of the ischaemic hemisphere using in vivo microdialysis. The in vivo salicylate trapping method was applied for monitoring hydroxyl radical formation via 2,3 dihydroxybenzoic acid (2,3 DHBA) detection. Caspase-3, neuronal nitric oxide synthase (nNOS) immunoreactivity and the volume of ischaemic damage were determined 24 h after the insult. In both the striatum and the cortex, Et-1-induced increases in glutamate, taurine and alanine were refractory to mild hypothermia. However, mild hypothermia significantly attenuated the ischaemia-induced 2,3 DHBA levels and the nNOS immunoreactivity in the cortex, but not in the striatum. These observations were associated with a decreased caspase-3 immunoreactivity. These results suggest that mild hypothermia exerts its neuroprotective effect in the penumbra partially by reducing nNOS activity and thereby preventing oxidative stress. Furthermore, we confirm our previous findings that the neuroprotective effect of resuscitative hypothermia is not mediated by changes in ischaemia-induced amino acid release as they could not be associated with the ischaemia-induced damage in the Et-1 rat model.

  10. Nitric oxide inhibits calpain-mediated proteolysis of talin in skeletal muscle cells

    NASA Technical Reports Server (NTRS)

    Koh, T. J.; Tidball, J. G.

    2000-01-01

    We tested the hypothesis that nitric oxide can inhibit cytoskeletal breakdown in skeletal muscle cells by inhibiting calpain cleavage of talin. The nitric oxide donor sodium nitroprusside prevented many of the effects of calcium ionophore on C(2)C(12) muscle cells, including preventing talin proteolysis and release into the cytosol and reducing loss of vinculin, cell detachment, and loss of cellular protein. These results indicate that nitric oxide inhibition of calpain protected the cells from ionophore-induced proteolysis. Calpain inhibitor I and a cell-permeable calpastatin peptide also protected the cells from proteolysis, confirming that ionophore-induced proteolysis was primarily calpain mediated. The activity of m-calpain in a casein zymogram was inhibited by sodium nitroprusside, and this inhibition was reversed by dithiothreitol. Previous incubation with the active site-targeted calpain inhibitor I prevented most of the sodium nitroprusside-induced inhibition of m-calpain activity. These data suggest that nitric oxide inhibited m-calpain activity via S-nitrosylation of the active site cysteine. The results of this study indicate that nitric oxide produced endogenously by skeletal muscle and other cell types has the potential to inhibit m-calpain activity and cytoskeletal proteolysis.

  11. Role of inducible nitric oxide synthase-derived nitric oxide in lipopolysaccharide plus interferon-gamma-induced pulmonary inflammation.

    PubMed

    Zeidler, Patti C; Millecchia, Lyndell M; Castranova, Vincent

    2004-02-15

    Exposure of mice to lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma) increases nitric oxide (NO) production, which is proposed to play a role in the resulting pulmonary damage and inflammation. To determine the role of inducible nitric oxide synthase (iNOS)-induced NO in this lung reaction, the responses of inducible nitric oxide synthase knockout (iNOS KO) versus C57BL/6J wild-type (WT) mice to aspirated LPS + IFN-gamma were compared. Male mice (8-10 weeks) were exposed to LPS (1.2 mg/kg) + IFN-gamma (5000 U/mouse) or saline. At 24 or 72 h postexposure, lungs were lavaged with saline and the acellular fluid from the first bronchoalveolar lavage (BAL) was analyzed for total antioxidant capacity (TAC), lactate dehydrogenase (LDH) activity, albumin, tumor necrosis factor-alpha (TNF-alpha), and macrophage inflammatory protein-2 (MIP-2). The cellular fraction of the total BAL was used to determine alveolar macrophage (AM) and polymorphonuclear leukocyte (PMN) counts, and AM zymosan-stimulated chemiluminescence (AM-CL). Pulmonary responses 24 h postexposure to LPS + IFN-gamma were characterized by significantly decreased TAC, increased BAL AMs and PMNs, LDH, albumin, TNF-alpha, and MIP-2, and enhanced AM-CL to the same extent in both WT and iNOS KO mice. Responses 72 h postexposure were similar; however, significant differences were found between WT and iNOS KO mice. iNOS KO mice demonstrated a greater decline in total antioxidant capacity, greater BAL PMNs, LDH, albumin, TNF-alpha, and MIP-2, and an enhanced AM-CL compared to the WT. These data suggest that the role of iNOS-derived NO in the pulmonary response to LPS + IFN-gamma is anti-inflammatory, and this becomes evident over time. PMID:14962504

  12. Up-regulation of endothelial nitric oxide activity as a central strategy for prevention of ischemic stroke - just say NO to stroke!

    PubMed

    McCarty, M F

    2000-11-01

    Nitric oxide (NO) produced by the endothelium of cerebral arterioles is an important mediator of endothelium-dependent vasodilation (EDV), and also helps to prevent thrombosis and vascular remodeling. A number of risk factors for ischemic stroke are associated with impaired EDV, and this defect is usually at least partially attributable to a decrease in the production and/or stability of NO. These risk factors include hypertension, high-sodium diets, homocysteine, diabetes, visceral obesity, and aging. Conversely, many measures which may provide protection from ischemic stroke - such as ample dietary intakes of potassium, arginine, fish oil, and selenium - can have a favorable impact on EDV. Protection afforded by exercise training, estrogen replacement, statin drugs, green tea polyphenols, and cruciferous vegetables may reflect increased expression of the endothelial NO synthase. IGF-I activity stimulates endothelial NO production, and conceivably is a mediator of the protection associated with higher-protein diets in Japanese epidemiology and in hypertensive rats. These considerations prompt the conclusion that modulation of NO availability is a crucial determinant of risk for ischemic stroke. Multifactorial strategies for promoting effective cerebrovascular NO activity, complemented by measures that stabilize platelets and moderate blood viscosity, should minimize risk for ischemic stroke and help maintain vigorous cerebral perfusion into ripe old age. The possibility that such measures will also diminish risk for Alzheimer's disease, and slow the normal age-related decline in mental acuity, merits consideration. A limited amount of ecologic epidemiology suggests that both stroke and senile dementia may be extremely rare in cultures still consuming traditional unsalted whole-food diets. Other lines of evidence suggest that promotion of endothelial NO activity may decrease risk for age-related macular degeneration. PMID:11058418

  13. Inhibition of protein synthesis by activation of NMDA receptors in cultured retinal cells: a new mechanism for the regulation of nitric oxide production.

    PubMed

    Cossenza, Marcelo; Cadilhe, Daniel V; Coutinho, Rodrigo N; Paes-de-Carvalho, Roberto

    2006-06-01

    The synthesis of nitric oxide (NO) is limited by the intracellular availability of L-arginine. Here we show that stimulation of NMDA receptors promotes an increase of intracellular L-arginine which supports an increase in the production of NO. Although L-[3H]arginine uptake measured in cultured chick retina cells incubated in the presence of cycloheximide (CHX, a protein synthesis inhibitor) was inhibited approximately 75% at equilibrium, quantitative thin-layer chromatography analysis showed that free intracellular L-[3H]arginine was six times higher in CHX-treated than in control cultures. Extracellular L-[3H]citrulline levels increased threefold in CHX-treated groups, an effect blocked by NG-nitro-L-arginine, a NO synthase (NOS) inhibitor. NMDA promoted a 40% increase of free intracellular L-[3H]arginine in control cultures, an effect blocked by the NMDA antagonist 2-amino 5-phosphonovaleric acid. In parallel, NMDA promoted a reduction of 40-50% in the incorporation of 35[S]methionine or L-[3H]arginine into proteins. Western blot analysis revealed that NMDA stimulates the phosphorylation of eukaryotic elongation factor 2 (eEF2, a factor involved in protein translation), an effect inhibited by (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK801). In conclusion, we have shown that the stimulation of NMDA receptors promotes an inhibition of protein synthesis and a consequent increase of an intracellular L-arginine pool available for the synthesis of NO. This effect seems to be mediated by activation of eEF2 kinase, a calcium/calmodulin-dependent enzyme which specifically phosphorylates and blocks eEF2. The results raise the possibility that NMDA receptor activation stimulates two different calmodulin-dependent enzymes (eEF2 kinase and NOS) reinforcing local NO production by increasing precursor availability together with NOS catalytic activity.

  14. Role of PECAM-1 in the shear-stress-induced activation of Akt and the endothelial nitric oxide synthase (eNOS) in endothelial cells.

    PubMed

    Fleming, Ingrid; Fisslthaler, Beate; Dixit, Madhulika; Busse, Rudi

    2005-09-15

    The application of fluid shear stress to endothelial cells elicits the formation of nitric oxide (NO) and phosphorylation of the endothelial NO synthase (eNOS). Shear stress also elicits the enhanced tyrosine phosphorylation of endothelial proteins, especially of those situated in the vicinity of cell-cell contacts. Since a major constituent of these endothelial cell-cell contacts is the platelet endothelial cell adhesion molecule-1 (PECAM-1) we assessed the role of PECAM-1 in the activation of eNOS. In human endothelial cells, shear stress induced the tyrosine phosphorylation of PECAM-1 and enhanced the association of PECAM-1 with eNOS. Endothelial cell stimulation with shear stress elicited the phosphorylation of Akt and eNOS as well as of the AMP-activated protein kinase (AMPK). While the shear-stress-induced tyrosine phosphorylation of PECAM-1 as well as the serine phosphorylation of Akt and eNOS were abolished by the pre-treatment of cells with the tyrosine kinase inhibitor PP1 the phosphorylation of AMPK was unaffected. Down-regulation of PECAM-1 using a siRNA approach attenuated the shear-stress-induced phosphorylation of Akt and eNOS, as well as the shear-stress-induced accumulation of cyclic GMP levels while the shear-stress-induced phosphorylation of AMPK remained intact. A comparable attenuation of Akt and eNOS (but not AMPK) phosphorylation and NO production was also observed in endothelial cells generated from PECAM-1-deficient mice. These data indicate that the shear-stress-induced activation of Akt and eNOS in endothelial cells is modulated by the tyrosine phosphorylation of PECAM-1 whereas the shear-stress-induced phosphorylation of AMPK is controlled by an alternative signaling pathway. PMID:16118242

  15. Immunolocalization, gene expression, and enzymatic activity of cyclooxygenases, prostaglandin e2-9-ketoreductase, and nitric oxide synthases in Mediterranean buffalo (Bubalus bubalis) corpora lutea during diestrus.

    PubMed

    Parillo, F; Catone, G; Maranesi, M; Gobbetti, A; Gasparrini, B; Russo, M; Boiti, C; Zerani, M

    2012-12-01

    Immunopresence, gene expression, and enzymatic activity of cyclooxygenase 1 (COX1), COX2, PGE2-9-ketoreductase (PGE2-9-K), endothelial (eNOS), and inducible nitric oxide synthases (iNOS), and hormone in vitro production were examined in early, mid, late, and regressive buffalo corpora lutea (CL). COX1 immunosignals were detected in the cytoplasm of small luteal cells, COX2 in large luteal cells, and PGE2-9-K in all luteal cells. COX2 and PGE2-9-K immunosignals were greater in late CL. Immunopresence of both NOS types were evidenced in the nuclei and cytoplasm of all luteal cells, as well as in the nuclei of endothelial cells, during all stages studied. The eNOS and iNOS immunosignals increased during the early stage. COX1 transcripts were lower in late and regressive CL, COX2 in late, PGE2-9-K higher in regressive, and iNOS higher in early and lower in regressive CL. COX1 enzymatic activity was lower in regressive CL, COX2 increased in mid and late stages, and PGE2-9-K was higher in late CL. Endothelial NOS activity was higher during mid and late stages and lower in regressive, whereas iNOS was greater in late and lower in early. Progesterone in vitro release was higher in mid and lower in late phase, while PGF2α synthesis was higher in late CL and lower in regressive, and PGE2 was higher during regressive stage. These results support the idea that COX, NOS, and PGE2-9-K regulate buffalo CL life span. In particular, regressive CL seems involved in the development of the contralateral early CL, through the production of the luteotrophic PGE2. PMID:22865504

  16. SOIL NITROUS OXIDE, NITRIC OXIDE, AND AMMONIA EMISSIONS FROM A RECOVERING RIPARIAN ECOSYSTEM IN SOUTHERN APPALACHIA

    EPA Science Inventory

    The paper presents two years of seasonal nitric oxide, ammonia, and nitrous oxide trace gas fluxes measured in a recovering riparian zone with cattle excluded and in an adjacent riparian zone grazed by cattle. In the recovering riparian zone, average nitric oxide, ammonia, and ni...

  17. Effects of nitric oxide on stem cell therapy.

    PubMed

    Wang, Wuchen; Lee, Yugyung; Lee, Chi H

    2015-12-01

    The use of stem cells as a research tool and a therapeutic vehicle has demonstrated their great potential in the treatment of various diseases. With unveiling of nitric oxide synthase (NOS) universally present at various levels in nearly all types of body tissues, the potential therapeutic implication of nitric oxide (NO) has been magnified, and thus scientists have explored new treatment strategies involved with stem cells and NO against various diseases. As the functionality of NO encompasses cardiovascular, neuronal and immune systems, NO is involved in stem cell differentiation, epigenetic regulation and immune suppression. Stem cells trigger cellular responses to external signals on the basis of both NO specific pathways and concerted action with endogenous compounds including stem cell regulators. As potency and interaction of NO with stem cells generally depend on the concentrations of NO and the presence of the cofactors at the active site, the suitable carriers for NO delivery is integral for exerting maximal efficacy of stem cells. The innovative utilization of NO functionality and involved mechanisms would invariably alter the paradigm of therapeutic application of stem cells. Future prospects in NO-involved stem cell research which promises to enhance drug discovery efforts by opening new era to improve drug efficacy, reduce drug toxicity and understand disease mechanisms and pathways, were also addressed.

  18. Nitric Oxide Signaling in Hypergravity-Induced Neuronal Plasticity

    NASA Technical Reports Server (NTRS)

    Holstein, Gay R.

    2003-01-01

    The goal of this research project was to identify the neurons and circuits in the vestibular nuclei and nucleus prepositus hypoglossi that utilize nitric oxide (NO) for intercellular signaling during gravity-induced plasticity. This objective was pursued using histochemical and immunocytochemical approaches to localize NO-producing neurons and characterize the fine morphology of the cells in ground-based studies of normal rats, rats adapted to hypergravity, and rats adapted to hypergravity and then re-adapted to the 1G environment. NO-producing neurons were identified and studied using four methodologies: i) immunocytochemistry employing polyclonal antibodies directed against neuronal nitric oxide synthase (nNOS), to provide an indication of the capacity of a cell for NO production; ii) immunocytochemistry employing a monoclonal antibody directed against L-citrulline, to provide an indirect index of the enzyme's activity; iii) histochemistry based on the NADPH-diaphorase reaction, for fuI1 cytological visualization of neurons; and iv) double immunofluorescence to co-localize nNOS and L-citrulline in individual vestibular nuclei (VN) and neurons.

  19. Endostatin induces acute endothelial nitric oxide and prostacyclin release

    SciTech Connect

    Li Chunying; Harris, M. Brennan; Venema, Virginia J.; Venema, Richard C. . E-mail: rvenema@mcg.edu

    2005-04-15

    Chronic exposure to endostatin (ES) blocks endothelial cell (EC) proliferation, and migration and induces EC apoptosis thereby inhibiting angiogenesis. Nitric oxide (NO) and prostacyclin (PGI{sub 2}), in contrast, play important roles in promoting angiogenesis. In this study, we examined the acute effects of ES on endothelial NO and PGI{sub 2} production. Unexpectedly, a cGMP reporter cell assay showed that ES-induced acute endothelial NO release in cultured bovine aortic endothelial cells (BAECs). Enzyme immunoassay showed that ES also induced an acute increase in PGI{sub 2} production in BAECs. These results were confirmed by ex vivo vascular ring studies that showed vascular relaxation in response to ES. Immunoblot analysis showed that ES stimulated acute phosphorylation of endothelial nitric oxide synthase (eNOS) at Ser116, Ser617, Ser635, and Ser1179, and dephosphorylation at Thr497 in BAECs, events associated with eNOS activation. Short-term exposure of EC to ES, therefore, unlike long-term exposure which is anti-angiogenic, may be pro-angiogenic.

  20. Potential role of inducible nitric oxide synthase in the sleep-wake states occurrence in old rats.

    PubMed

    Clément, P; Sarda, N; Cespuglio, R; Gharib, A

    2005-01-01

    Extensive evidences now suggest that an association between inducible nitric oxide synthase and oxidative stress takes place during aging. Since the part played by inducible nitric oxide synthase in the sleep impairments associated with aging still remains unexplored, we compared its involvement in old rats (20-24 months) versus adult ones (3-5 months) using polygraphic, biochemical, voltammetric and immunohistochemical techniques. The experiments were conducted either in basal condition or after a systemic injection of selected inducible nitric oxide synthase inhibitors. We found that 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (10 mg/kg, i.p.) or aminoguanidine (400 mg/kg, i.p.) was capable to suppress rapid-eye-movement sleep and induce a delayed enhancement in slow-wave sleep in old rats. These effects did not occur in adult animals. Within the frontal cortex, the laterodorsal tegmentum and dorsal raphe nuclei, the basal inducible nitric oxide synthase activity was 85-200% higher in old rats than in adult ones. In contrast, the neuronal nitric oxide synthase activity did not vary in both groups. 2-Amino-5,6-dihydro-6-methyl-4H-1,3-thiazine administration significantly reduced inducible nitric oxide synthase activity (70-80% according to the brain areas) independently of age, but significantly decreased the cortical nitric oxide release in old rats. Finally, in frontal cortex and dorsal raphe immunohistochemical analysis showed inducible nitric oxide synthase-positive cells again only in old animals. These data support the idea that nitric oxide produced by inducible nitric oxide synthase plays a role in the triggering and maintenance of rapid-eye-movement sleep during aging.

  1. Involvement of large-conductance Ca(2+) -activated K(+) channels in both nitric oxide and endothelium-derived hyperpolarization-type relaxation in human penile small arteries.

    PubMed

    Király, István; Pataricza, János; Bajory, Zoltán; Simonsen, Ulf; Varro, András; Papp, Julius Gy; Pajor, Lászlo; Kun, Attila

    2013-07-01

    Large-conductance Ca(2+) -activated K(+) channels (BKC a ), located on the vascular smooth muscle, play an important role in regulation of vascular tone. In penile corpus cavernosum tissue, opening of BKC a channels leads to relaxation of corporal smooth muscle, which is essential during erection; however, there is little information on the role of BKC a channels located in penile vascular smooth muscle. This study was designed to investigate the involvement of BKC a channels in endothelium-dependent and endothelium-independent relaxation of human intracavernous penile arteries. In human intracavernous arteries obtained in connection with transsexual operations, change in isometric force was recorded in microvascular myographs, and endothelium-dependent [nitric oxide (NO) and endothelium-derived hyperpolarization (EDH)-type] and endothelium-independent (NO-donor) relaxations were measured in contracted arteries. In penile small arteries contracted with phenylephrine, acetylcholine evoked NO- and EDH-type relaxations, which were sensitive to iberiotoxin (IbTX), a selective blocker of BKC a channels. Iberiotoxin also inhibited relaxations induced by a NO-donor, sodium nitroprusside. NS11021, a selective opener of BKC a channels, evoked pronounced relaxations that were inhibited in the presence of IbTX. NS13558, a BKC a -inactive analogue of NS11021, failed to relax human penile small arteries. Our results show that BKC a channels are involved in both NO- and EDH-type relaxation of intracavernous penile arteries obtained from healthy men. The effect of a selective opener of BKC a channels also suggests that direct activation of the channel may be an advantageous approach for treatment of impaired endothelium-dependent relaxation often associated with erectile dysfunction.

  2. Potassium inhibits nitric oxide and adenosine arteriolar vasodilatation via K(IR) and Na(+)/K(+) ATPase: implications for redundancy in active hyperaemia.

    PubMed

    Lamb, Iain R; Murrant, Coral L

    2015-12-01

    Redundancy, in active hyperaemia, where one vasodilator can compensate for another if the first is missing, would require that one vasodilator inhibits the effects of another; therefore, if the first vasodilator is inhibited, its inhibitory influence on the second vasodilator is removed and the second vasodilator exerts a greater vasodilatory effect. We aimed to determine whether vasodilators relevant to skeletal muscle contraction [potassium chloride (KCl), adenosine (ADO) and nitric oxide] inhibit one another and, in addition, to investigate the mechanisms for this interaction. We used the hamster cremaster muscle and intravital microscopy to directly visualize 2A arterioles when exposed to a range of concentrations of one vasodilator [10(-8) to 10(-5) M S-nitroso-N-acetyl penicillamine (SNAP), 10(-8) to 10(-5) M ADO, 10 and 20 mM KCl] in the absence and then in the presence of a second vasodilator (10(-7) M ADO, 10(-7) M SNAP, 10 mM KCl). We found that KCl significantly attenuated SNAP-induced vasodilatations by ∼65.8% and vasodilatations induced by 10(-8) to 10(-6) M ADO by ∼72.8%. Furthermore, we observed that inhibition of KCl vasodilatation, by antagonizing either Na(+)/K(+) ATPase using ouabain or inward rectifying potassium channels using barium chloride, could restore the SNAP-induced vasodilatation by up to ∼53.9% and 30.6%, respectively, and also restore the ADO-induced vasodilatations by up to ∼107% and 76.7%, respectively. Our data show that vasodilators relevant to muscle contraction can interact in a way that alters the effectiveness of other vasodilators. These data suggest that active hyperaemia may be the result of complex interactions between multiple vasodilators via a redundant control paradigm.

  3. Argininosuccinate synthetase mRNA and activity are induced by immunostimulants in vascular smooth muscle. Role in the regeneration or arginine for nitric oxide synthesis.

    PubMed

    Hattori, Y; Campbell, E B; Gross, S S

    1994-04-01

    Nitric oxide synthase produces NO, citrulline, water, and NADP at the expense of arginine, NADPH, and dioxygen. While citrulline has been considered to be an inert by-product of the high output inducible isoform of NO synthase (iNOS), we show here that immunostimulants induce a metabolic pathway in vascular smooth muscle cells, which enables them to regenerate arginine from citrulline. Regeneration of arginine from citrulline is accomplished by two urea cycle enzymes: arginino-succinate synthetase (AS) and argininosuccinate lyase (AL). Whereas AL is constitutive to vascular smooth muscle cells, AS mRNA and enzyme activity is markedly induced in cells by treatment with bacterial lipopolysaccharide (LPS). The induction of AS mRNA and activity by LPS follows a time course which mirrors that for iNOS but lags 1-2 h behind. As shown for iNOS, interferon-gamma does not itself induce AS but is synergistic with LPS. AS induction is suppressed by glucocorticoids, actinomycin D, and, to a lesser extent, cycloheximide. On the other hand, AS induction is unaffected by an excess of citrulline or the inhibitor of iNOS, N omega-methyl-L-arginine. Our results show the urea cycle enzymes AS and AL confer cells with the capacity to produce NO without a need for exogenous arginine. In conjunction with NOS, citric acid cycle enzymes that covert fumarate to oxaloacetate (fumarase and malate dehydrogenase) and oxaloacetate to aspartate (aspartate transaminase), AS and AL form a novel arginine-citrulline cycle that enables high output NO production by cells. PMID:7511585

  4. Nitrite Reductase and Nitric-oxide Synthase Activity of the Mitochondrial Molybdopterin Enzymes mARC1 and mARC2*

    PubMed Central

    Sparacino-Watkins, Courtney E.; Tejero, Jesús; Sun, Bin; Gauthier, Marc C.; Thomas, John; Ragireddy, Venkata; Merchant, Bonnie A.; Wang, Jun; Azarov, Ivan; Basu, Partha; Gladwin, Mark T.

    2014-01-01

    Mitochondrial amidoxime reducing component (mARC) proteins are molybdopterin-containing enzymes of unclear physiological function. Both human isoforms mARC-1 and mARC-2 are able to catalyze the reduction of nitrite when they are in the reduced form. Moreover, our results indicate that mARC can generate nitric oxide (NO) from nitrite when forming an electron transfer chain with NADH, cytochrome b5, and NADH-dependent cytochrome b5 reductase. The rate of NO formation increases almost 3-fold when pH was lowered from 7.5 to 6.5. To determine if nitrite reduction is catalyzed by molybdenum in the active site of mARC-1, we mutated the putative active site cysteine residue (Cys-273), known to coordinate molybdenum binding. NO formation was abolished by the C273A mutation in mARC-1. Supplementation of transformed Escherichia coli with tungsten facilitated the replacement of molybdenum in recombinant mARC-1 and abolished NO formation. Therefore, we conclude that human mARC-1 and mARC-2 are capable of catalyzing reduction of nitrite to NO through reaction with its molybdenum cofactor. Finally, expression of mARC-1 in HEK cells using a lentivirus vector was used to confirm cellular nitrite reduction to NO. A comparison of NO formation profiles between mARC and xanthine oxidase reveals similar Kcat and Vmax values but more sustained NO formation from mARC, possibly because it is not vulnerable to autoinhibition via molybdenum desulfuration. The reduction of nitrite by mARC in the mitochondria may represent a new signaling pathway for NADH-dependent hypoxic NO production. PMID:24500710

  5. The nitric oxide redox sibling nitroxyl partially circumvents impairment of platelet nitric oxide responsiveness.

    PubMed

    Dautov, R F; Ngo, D T M; Licari, G; Liu, S; Sverdlov, A L; Ritchie, R H; Kemp-Harper, B K; Horowitz, J D; Chirkov, Y Y

    2013-11-30

    Impaired platelet responsiveness to nitric oxide (NO resistance) is a common characteristic of many cardiovascular disease states and represents an independent risk factor for cardiac events and mortality. NO resistance reflects both scavenging of NO by superoxide (O2(-)), and impairment of the NO receptor, soluble guanylate cyclase (sGC). There is thus an urgent need for circumvention of NO resistance in order to improve clinical outcomes. Nitroxyl (HNO), like NO, produces vasodilator and anti-aggregatory effects, largely via sGC activation, but is not inactivated by O2(-). We tested the hypothesis that HNO circumvents NO resistance in human platelets. In 57 subjects with or without ischemic heart disease, platelet responses to the HNO donor isopropylamine NONOate (IPA/NO) and the NO donor sodium nitroprusside (SNP) were compared. While SNP (10μM) induced 29±3% (p<0.001) inhibition of platelet aggregation, IPA/NO (10μM) caused 75±4% inhibition (p<0.001). In NO-resistant subjects (n=28), the IPA/NO:SNP response ratio was markedly increased (p<0.01), consistent with partial circumvention of NO resistance. Similarly, cGMP accumulation in platelets was greater (p<0.001) with IPA/NO than with SNP stimulation. The NO scavenger carboxy-PTIO (CPTIO, 200μM) inhibited SNP and IPA/NO responses by 92±7% and 17±4% respectively (p<0.001 for differential inhibition), suggesting that effects of IPA/NO are only partially NO-mediated. ODQ (10μM) inhibited IPA/NO responses by 36±8% (p<0.001), consistent with a contribution of sGC/haem to IPA/NO inhibition of aggregation. There was no significant relationship between whole blood ROS content and IPA/NO responses. Thus the HNO donor IPA/NO substantially circumvents platelet NO resistance while acting, at least partially, as a haem-mediated sGC activator.

  6. Development of anion- and nitric oxide-selective chemical sensors and biosensors

    NASA Astrophysics Data System (ADS)

    Barker, Susan Lynn Ritenour

    1999-11-01

    times and complete reversibility, making these sensors applicable to dynamic measurements of cellular nitric oxide. Extra- and intracellular nitric oxide were measured in unactivated and activated macrophages. The macrophages were activated with interferon-γ (IFN-γ) and lipopolysaccharide (LPS), known stimulants of macrophage nitric oxide production. Both protein and dye-based fiber optic ratiometric sensors have been used to determine the macrophage produced extracellular nitric oxide concentration. For intracellular measurements, the dye- cytochrome c' complex was scrape- loaded into the cytoplasm of the macrophages.

  7. Extract of Hypericum perforatum blocks caffeine-induced locomotor activity in mice: a possible role of nitric oxide.

    PubMed

    Uzbay, I Tayfun; Coskun, Ilke; Kayir, Hakan; Ozturk, Nilgun; Ozturk, Yusuf

    2007-05-01

    The present study investigated the effects of HPE on caffeine-induced locomotor activity in mice. Caffeine (4-16 mg/kg) or saline were given to adult male Swiss-Webster mice, and the locomotor activity was immediately measured for 30 min. HPE (6-48 mg/kg) and saline were injected to another group of mice and the locomotor activity was measured 20 min later. HPE (6-24 mg/kg) was also administered to another group of mice 20 min before caffeine (16 mg/kg) injections and the locomotor activity was recorded for 30 min immediately after caffeine administrations. Finally l-arginine (1 g/kg) was administered i.p. 20 min before HPE (6 mg/kg) and the locomotor activity was measured as mentioned above. Each group of mice was used only once. Caffeine produced some significant increases in locomotor activity of the mice. HPE (6-24 mg/kg) significantly blocked the caffeine-induced locomotor hyperactivity. Pretreatment of l-arginine (1 g/kg) reversed the inhibitory effect of HPE (6 mg/kg) on caffeine-induced locomotor activity without producing any significant effect on locomotor activity of the mice when it was administered alone. The results suggest that HPE blocks caffeine-induced locomotor hyperactivity in mice. Furthermore, the inhibitory effect of HPE on caffeine-induced locomotor activity may be related to its NOS inhibitory property.

  8. Vanillic acid prevents the deregulation of lipid metabolism, endothelin 1 and up regulation of endothelial nitric oxide synthase in nitric oxide deficient hypertensive rats.

    PubMed

    Kumar, Subramanian; Prahalathan, Pichavaram; Saravanakumar, Murugesan; Raja, Boobalan

    2014-11-15

    Hypertension is one of the main factors causing cardiovascular diseases. The present study was designed to evaluate the protective effect of vanillic acid against nitric oxide deficient rats. Hypertension was induced in adult male albino rats of Wistar strain, weighing 180-220g, by oral administration of N(ω)-nitro-l arginine methyl ester (l-NAME) 40mg/kg in drinking water for 4 weeks. Vanillic acid was administered orally at a dose of 50mg/kg b.w. Nitric oxide deficient rats showed increased levels of mean arterial pressure (MAP), heart rate (HR) and decreased heart nitric oxide metabolites (NOx). A significant increase in the levels of plasma cholesterol, low density lipoprotein-cholesterol (LDL-C), very low density lipoprotein-cholesterol (VLDL-C), triglycerides (TG), free fatty acids (FFA), phospholipids (PL), 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase in the plasma, liver and kidney and decreased level of high density lipoprotein-cholesterol (HDL-C) are observed, whereas there is a decrease in the activities of plasma lipoprotein lipase (LPL) and lecithin cholesterol acyl transferase (LCAT) in nitric oxide deficient rats. l-NAME rats also showed an increase in TC, TG, FFA and PL levels in the liver and kidney tissues. Vanillic acid treatment brought the above parameters towards near normal level. Moreover the down regulated endothelial nitric oxide synthase (eNOS) and up regulated expression of endothelin 1 (ET1) components was also attenuated by vanillic acid treatment. All the above outcomes were confirmed by the histopathological examination. These results suggest that vanillic acid has enough potential to attenuate hypertension, dyslipidemia and hepatic and renal damage in nitric oxide deficient rats. PMID:25239071

  9. Racial Differences in Nitric Oxide-Dependent Vasorelaxation

    PubMed Central

    Mata-Greenwood, Eugenia; Chen, Dong-Bao

    2008-01-01

    Along with the growing heterogeneity of the American population, ethnic/racial disparity is becoming a clear health issue in the United States. The awareness of ethnic/racial disparities has been growing because of considerable data gathered from recent clinical and epidemiological studies. These studies have highlighted the importance of addressing these differences in the diagnosis and treatment of various diseases potentially according to race. It is becoming particularly clear that there is a 2- to 3-fold racial difference in certain cardiovascular diseases (eg, preeclampsia) associated with dysfunctional nitric oxide–mediated vasodilation. In this review, the authors summarize the current literature on racial disparities in nitric oxide–mediated vasodilation in relation to cardiovascular health with an emphasis on vascular nitric oxide bioavailability as a balance between production via endothelial nitric oxide synthase and degradation through reactive oxygen species. The major hypotheses postulated on the biological basis of these differences are also highlighted. PMID:18212350

  10. JS-K, a glutathione/glutathione S-transferase-activated nitric oxide releasing prodrug inhibits androgen receptor and WNT-signaling in prostate cancer cells

    PubMed Central

    2012-01-01

    Background Nitric oxide (NO) and its oxidative reaction products have been repeatedly shown to block steroid receptor function via nitrosation of zinc finger structures in the DNA-binding domain (DBD). In consequence NO-donors could be of special interest for the treatment of deregulated androgen receptor(AR)-signaling in castration resistant prostate cancer (CRPC). Methods Prostate cancer (PCa) cells were treated with JS-K, a diazeniumdiolate derivate capable of generating large amounts of intracellular NO following activation by glutathione S-transferase. Generation of NO was determined indirectly by the detection of nitrate in tissue culture medium or by immunodetection of nitrotyrosine in the cytoplasm. Effects of JS-K on intracellular AR-levels were determined by western blotting. AR-dimerization was analyzed by mammalian two hybrid assay, nuclear translocation of the AR was visualized in PCa cells transfected with a green fluorescent AR-Eos fusion protein using fluorescence microscopy. Modulation of AR- and WNT-signalling by JS-K was investigated using reporter gene assays. Tumor cell proliferation following JS-K treatment was measured by MTT-Assay. Results The NO-releasing compound JS-K was shown to inhibit AR-mediated reporter gene activity in 22Rv1 CRPC cells. Inhibition of AR signaling was neither due to an inhibition of nuclear import nor to a reduction in AR-dimerization. In contrast to previously tested NO-donors, JS-K was able to reduce the intracellular concentration of functional AR. This could be attributed to the generation of extremely high intracellular levels of the free radical NO as demonstrated indirectly by high levels of nitrotyrosine in JS-K treated cells. Moreover, JS-K diminished WNT-signaling in AR-positive 22Rv1 cells. In line with these observations, castration resistant 22Rv1 cells were found to be more susceptible to the growth inhibitory effects of JS-K than the androgen dependent LNCaP which do not exhibit an active WNT

  11. Rescue of PINK1 Protein Null-specific Mitochondrial Complex IV Deficits by Ginsenoside Re Activation of Nitric Oxide Signaling*

    PubMed Central

    Kim, Kyung-Hee; Song, Karen; Yoon, Seung-Hee; Shehzad, Omer; Kim, Yeong-Shik; Son, Jin H.

    2012-01-01

    PINK1, linked to familial Parkinson's disease, is known to affect mitochondrial function. Here we identified a novel regulatory role of PINK1 in the maintenance of complex IV activity and characterized a novel mechanism by which NO signaling restored complex IV deficiency in PINK1 null dopaminergic neuronal cells. In PINK1 null cells, levels of specific chaperones, including Hsp60, leucine-rich pentatricopeptide repeat-containing (LRPPRC), and Hsp90, were severely decreased. LRPPRC and Hsp90 were found to act upstream of Hsp60 to regulate complex IV activity. Specifically, knockdown of Hsp60 resulted in a decrease in complex IV activity, whereas antagonistic inhibition of Hsp90 by 17-(allylamino) geldanamycin decreased both Hsp60 and complex IV activity. In contrast, overexpression of the PINK1-interacting factor LRPPRC augmented complex IV activity by up-regulating Hsp60. A similar recovery of complex IV activity was also induced by coexpression of Hsp90 and Hsp60. Drug screening identified ginsenoside Re as a compound capable of reversing the deficit in complex IV activity in PINK1 null cells through specific increases of LRPPRC, Hsp90, and Hsp60 levels. The pharmacological effects of ginsenoside Re could be reversed by treatment of the pan-NOS inhibitor l-NG-Nitroarginine Methyl Ester (l-NAME) and could also be reproduced by low-level NO treatment. These results suggest that PINK1 regulates complex IV activity via interactions with upstream regulators of Hsp60, such as LRPPRC and Hsp90. Furthermore, they demonstrate that treatment with ginsenoside Re enhances functioning of the defective PINK1-Hsp90/LRPPRC-Hsp60-complex IV signaling axis in PINK1 null neurons by restoring NO levels, providing potential for new therapeutics targeting mitochondrial dysfunction in Parkinson's disease. PMID:23144451

  12. Rescue of PINK1 protein null-specific mitochondrial complex IV deficits by ginsenoside Re activation of nitric oxide signaling.

    PubMed

    Kim, Kyung-Hee; Song, Karen; Yoon, Seung-Hee; Shehzad, Omer; Kim, Yeong-Shik; Son, Jin H

    2012-12-28

    PINK1, linked to familial Parkinson's disease, is known to affect mitochondrial function. Here we identified a novel regulatory role of PINK1 in the maintenance of complex IV activity and characterized a novel mechanism by which NO signaling restored complex IV deficiency in PINK1 null dopaminergic neuronal cells. In PINK1 null cells, levels of specific chaperones, including Hsp60, leucine-rich pentatricopeptide repeat-containing (LRPPRC), and Hsp90, were severely decreased. LRPPRC and Hsp90 were found to act upstream of Hsp60 to regulate complex IV activity. Specifically, knockdown of Hsp60 resulted in a decrease in complex IV activity, whereas antagonistic inhibition of Hsp90 by 17-(allylamino) geldanamycin decreased both Hsp60 and complex IV activity. In contrast, overexpression of the PINK1-interacting factor LRPPRC augmented complex IV activity by up-regulating Hsp60. A similar recovery of complex IV activity was also induced by coexpression of Hsp90 and Hsp60. Drug screening identified ginsenoside Re as a compound capable of reversing the deficit in complex IV activity in PINK1 null cells through specific increases of LRPPRC, Hsp90, and Hsp60 levels. The pharmacological effects of ginsenoside Re could be reversed by treatment of the pan-NOS inhibitor L-NG-Nitroarginine Methyl Ester (L-NAME) and could also be reproduced by low-level NO treatment. These results suggest that PINK1 regulates complex IV activity via interactions with upstream regulators of Hsp60, such as LRPPRC and Hsp90. Furthermore, they demonstrate that treatment with ginsenoside Re enhances functioning of the defective PINK1-Hsp90/LRPPRC-Hsp60-complex IV signaling axis in PINK1 null neurons by restoring NO levels, providing potential for new therapeutics targeting mitochondrial dysfunction in Parkinson's disease. PMID:23144451

  13. Nitric oxide as a mediator of gastrointestinal mucosal injury?—Say it ain't so

    PubMed Central

    Kubes, Paul

    1995-01-01

    Nitric oxide has been suggested as a contributor to tissue injury in various experimental models of gastrointestinal inflammation. However, there is overwhelming evidence that nitric oxide is one of the most important mediators of mucosal defence, influencing such factors as mucus secretion, mucosal blood flow, ulcer repair and the activity of a variety of mucosal immunocytes. Nitric oxide has the capacity to down-regulate inflammatory responses in the gastrointestinal tract, to scavenge various free radical species and to protect the mucosa from injury induced by topical irritants. Moreover, questions can be raised regarding the evidence purported to support a role for nitric oxide in producing tissue injury. In this review, we provide an overview of the evidence supporting a role for nitric oxide in protecting the gastrointestinal tract from injury. PMID:18475671

  14. Arctigenin promotes degradation of inducible nitric oxide synthase through CHIP-associated proteasome pathway and suppresses its enzyme activity.

    PubMed

    Yao, Xiangyang; Li, Guilan; Lü, Chaotian; Xu, Hui; Yin, Zhimin

    2012-10-01

    Arctigenin, a natural dibenzylbutyrolactone lignan compound, has been reported to possess anti-inflammatory properties. Previous works showed that arctigenin decreased lipopolysaccharide (LPS)-induced iNOS at transcription level. However, whether arctigenin could regulate iNOS at the post-translational level is still unclear. In the present study, we demonstrated that arctigenin promoted the degradation of iNOS which is expressed under LPS stimulation in murine macrophage-like RAW 264.7 cells. Such degradation of iNOS protein is due to CHIP-associated ubiquitination and proteasome-dependency. Furthermore, arctigenin decreased iNOS phosphorylation through inhibiting ERK and Src activation, subsequently suppressed iNOS enzyme activity. In conclusion, our research displays a new finding that arctigenin can promote the ubiqitination and degradation of iNOS after LPS stimulation. iNOS activity regulated by arctigenin is likely to involve a multitude of crosstalking mechanisms.

  15. The reactions of copper proteins with nitric oxide.

    PubMed

    Torres, J; Wilson, M T

    1999-05-01

    Nitric oxide (NO) can act as a ligand for copper atoms and may also engage in redox chemistry with the metal once bound. Furthermore NO posses an unpaired electron which can couple with the unpaired electron on Cu2+. These properties have been exploited to probe the active sites of copper-containing enzymes and proteins. We review these studies. In addition to the use as a spectroscopic probe for the active site we draw attention to the rapid reactions of NO at the copper sites in Cytochrome c oxidase (CcO) and laccase. These reactions in CcO occur in the ms time range, at low NO concentrations and in the presence of oxygen and may therefore be of physiological relevance to the control of respiration. Finally we speculate on the wider role that NO may play in regulation of an important group of Type 2 copper containing enzymes. PMID:10320665

  16. Nitric oxide inhibitory constituents from the barks of Cinnamomum cassia.

    PubMed

    He, Shan; Zeng, Ke-Wu; Jiang, Yong; Tu, Peng-Fei

    2016-07-01

    Six new compounds including one γ-butyrolactone, cinncassin A (1), two tetrahydrofuran derivatives, cinncassins B and C (2, 3), two lignans, cinncassins D and E (4, 5), and one phenylpropanol glucoside, cinnacassoside D (6), together with 14 known lignans (7-20) were isolated from the barks of Cinnamomum cassia. The structures of 1-6 were elucidated by extensive 1D and 2D NMR spectroscopic data analysis as well as chemical methods, and the absolute configurations were established by experimental and calculated ECD data. The anti-inflammatory activities of the isolates were evaluated on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 microglial cells. Compounds 5, 7, 8, and 15 showed potent inhibition activities with IC50 values of 17.6, 17.7, 18.7, and 17.5μM, respectively. PMID:27223848

  17. Hemoglobin, nitric oxide and molecular mechanisms of hypoxic vasodilation

    PubMed Central

    Allen, Barry W.; Stamler, Jonathan S.; Piantadosi, Claude A.

    2009-01-01

    The protected transport of nitric oxide (NO) by hemoglobin (Hb) links the metabolic activity of working tissue to the regulation of its local blood supply through hypoxic vasodilation. This physiologic mechanism is allosterically coupled to the O2 saturation of Hb and involves the covalent binding of NO to a cysteine residue in the β-chain of Hb (Cys β93) to form S-nitrosohemoglobin (SNO-Hb). Subsequent S-transnitrosation, the transfer of NO groups to thiols on the RBC membrane and then in the plasma, preserves NO vasodilator activity for delivery to the vascular endothelium. This SNO-Hb paradigm provides insight into the respiratory cycle and a new therapeutic focus for diseases involving abnormal microcirculatory perfusion. In addition, the formation of S-nitrosothiols in other proteins may regulate an array of physiological functions. PMID:19781996

  18. Endothelial nitric oxide synthase negatively regulates hydrogen peroxide-stimulated AMP-activated protein kinase in endothelial cells.

    PubMed

    Jin, Benjamin Y; Sartoretto, Juliano L; Gladyshev, Vadim N; Michel, Thomas

    2009-10-13

    Hydrogen peroxide and other reactive oxygen species are intimately involved in endothelial cell signaling. In many cell types, the AMP-activated protein kinase (AMPK) has been implicated in the control of metabolic responses, but the role of endothelial cell redox signaling in the modulation of AMPK remains to be completely defined. We used RNA interference and pharmacological methods to establish that H(2)O(2) is a critical activator of AMPK in cultured bovine aortic endothelial cells (BAECs). H(2)O(2) treatment of BAECs rapidly and significantly increases the phosphorylation of AMPK. The EC(50) for H(2)O(2)-promoted phosphorylation of AMPK is 65 + or - 15 microM, within the physiological range of cellular H(2)O(2) concentrations. The Ca(2+)/calmodulin-dependent protein kinase kinase-beta (CaMKKbeta) inhibitor STO-609 abolishes H(2)O(2)-dependent AMPK activation, whereas eNOS inhibitors enhance AMPK activation. Similarly, siRNA-mediated knockdown of CaMKKbeta abrogates AMPK activation, whereas siRNA-mediated knockdown of eNOS leads to a striking increase in AMPK phosphorylation. Cellular imaging studies using the H(2)O(2) biosensor HyPer show that siRNA-mediated eNOS knockdown leads to a marked increase in intracellular H(2)O(2) generation, which is blocked by PEG-catalase. eNOS(-/-) mice show a marked increase in AMPK phosphorylation in liver and lung compared to wild-type mice. Lung endothelial cells from eNOS(-/-) mice also show a significant increase in AMPK phosphorylation. Taken together, these results establish that CaMKKbeta is critically involved in mediating the phosphorylation of AMPK promoted by H(2)O(2) in endothelial cells, and document that eNOS is an important negative regulator of AMPK phosphorylation and intracellular H(2)O(2) generation in endothelial cells. PMID:19805165

  19. Suppression of inducible nitric oxide synthase pathway by 7-deacetylgedunin, a limonoid from Xylocarpus sp.

    PubMed

    Sarigaputi, Chanin; Sangpech, Nuanpan; Palaga, Tanapat; Pudhom, Khanitha

    2015-03-01

    In this study, limonoids isolated from Xylocarpus plants were tested for their in vitro anti-inflammatory effects. The results demonstrated that only 7-deacetylgedunin (1), a gedunin-type limonoid, significantly inhibited lipopolysaccharide- and interferon-γ-stimulated production of nitric oxide in murine macrophage RAW 264.7 cells. The suppression of nitric oxide production by 1 was correlated with the downregulation of mRNA and protein expression of inducible nitric oxide synthase. Mechanistic studies revealed that the transcriptional activity of nuclear factor-κB, IκBα degradation, and the activation of mitogen-activated protein kinases, stimulated with lipopolysaccharide and interferon-γ, were suppressed by 1. PMID:25714725

  20. Pregnancy enhances sustained Ca2+ bursts and endothelial nitric oxide synthase activation in ovine uterine artery endothelial cells through increased connexin 43 function.

    PubMed

    Yi, Fu-Xian; Boeldt, Derek S; Gifford, Shannon M; Sullivan, Jeremy A; Grummer, Mary A; Magness, Ronald R; Bird, Ian M

    2010-01-01

    Endothelium-mediated vasodilation is specifically enhanced in uterine circulation during pregnancy, and production of nitric oxide (NO) is increased in response to a wide array of agonists. Uterine artery endothelial cells from nonpregnant (NP-UAECs) or pregnant (P-UAECs) ewes maintained in culture still show a pregnancy-enhanced difference in ATP-stimulated endothelial NO synthase (eNOS; official symbol NOS3) activation, even though NOS3 protein, purinergic receptors, and associated cell signaling proteins are expressed at equal levels. We have also shown that the pregnancy-enhanced endothelial cell NO response to ATP requires an enhanced and sustained capacitative entry phase that is likely mediated via canonical transient receptor potential protein/inositol 1,4,5-trisphosphate receptor type 2 interaction. In this study, we now show by simultaneous video imaging of individual Fura-2-loaded cells that the pregnancy-enhanced capacitative entry phase is not continuous and equal in all cells, but is in fact mediated as a series of periodic [Ca(2+)](i) bursts within individual cells. Not only does pregnancy increase the number of bursts over a longer time period in individual cells, but also a greater proportion of cells exhibit this burst activity, and at high cell density this occurs in a synchronous manner. The mediator of cell synchronization is connexin 43 (Cx43) gap junctions because 1) Cx43 is readily detectable by Western blot analysis in UAECs, whereas Cx40 and Cx37 are weakly detected or absent, and 2) pregnancy-specific enhancement of [Ca(2+)](i) bursts by ATP is blocked by inhibitory loop peptides selective to Cx43 ((43,37)GAP27) but not by a scrambled control peptide or (40)GAP27 or (40,37)GAP26 peptides, which are specific to Cx40 or Cx37. The relationship between Ca(2+) bursts and NOS3 activation is further established by the finding that (43,37)GAP27 inhibits ATP-stimulated NOS3 activation but has no effect on cell mitogenesis. We conclude that it is

  1. Nitric oxide and exercise in the horse.

    PubMed Central

    Mills, P C; Marlin, D J; Demoncheaux, E; Scott, C; Casas, I; Smith, N C; Higenbottam, T

    1996-01-01

    1. The effects of exercise on the production rate of nitric oxide (NO) in exhaled air (VNO) and the effects of inhaled NO (80 p.p.m.) on cardiovascular and respiratory parameters were investigated in five Throughbred horses. 2. The concentration of NO ([NO]) in exhaled air collected from within the nasal opening was lower when collected at a high flow rate of 80 l min-1 than at a low flow rate of 20 l min-1: when trotting at 3.7 m s-1 the values were 0.78 +/- 0.15 and 1.23 +/- 9.14 p.p.b., respectively, and when cantering at 9 m s-1 the values were 1.69 +/- 0.31 and 2.25 +/- 0.32 p.p.b., respectively. 3. Nebulized methoxamine (40 mg ml-1 for 60 s), an alpha 1-adrenergic agonist, further reduced [NO] during the 9 m s-1 canter to 1.05 +/- 0.14 and 1.99 +/- 0.41 p.p.b. when collected at 80 and 20 l min-1, respectively, and induced cyclical changes in the breathing pattern. 4. Exercise induced a linear increase in VNO with work intensity to a maximum (428.1 +/- 31.6 pmol min-1 kg-1) which coincided with the maximal oxygen uptake for the horses (138.3 +/- 11.7 ml min-1 kg-1), although a further increase in VNO (779.3 +/- 38.4 pmol min-1 kg-1) occurred immediately after exercise. The changes in VNO correlated well with the tidal volume (r = 0.968; P < 0.01) and the haematocrit (r = 0.855; P < 0.01). 5. In the first 2 min of high intensity exercise, inhaled NO (80 p.p.m.) significantly (P < 0.05) reduced the pulmonary artery pressure: during the first minute, pulmonary artery pressure was 83.1 +/- 7.6 mmHg compared with a control value of 94.4 +/- 6.3 mmHg, and during the second minute, 84.2 +/- 7.1 mmHg compared with a control value of 98.4 +/- 4.7 mmHg. There were no other significant changes in cardiovascular or respiratory indices, including cardiac output, measured during exercise between control and inhaled NO tests. 6. The results show that exhaled NO is released from the airways of the horse and may contribute to the regulation of pulmonary vascular tone during

  2. Biphasic regulation of NF-kappa B activity underlies the pro- and anti-inflammatory actions of nitric oxide.

    PubMed

    Connelly, L; Palacios-Callender, M; Ameixa, C; Moncada, S; Hobbs, A J

    2001-03-15

    Expression of inducible NO synthase (iNOS) by macrophages is a prerequisite for the production of high output NO, which mediates many bactericidal and tumoricidal actions of these immune cells. The expression of iNOS in mammalian cells is governed predominantly by the transcription factor, NF-kappa B, which regulates the expression of many host defense proteins. In the present study, we characterize a novel, biphasic effect of NO on NF-kappa B activity in murine macrophages. This mechanism depends on the local concentration of NO and enables it both to up- and down-regulate the expression of host defense proteins including iNOS, cyclooxygenase-2, and IL-6. This biphasic activity of NO appears to play a pivotal role in the time course of activation of these immune cells and, by inference, in facilitating the initiation of a defense response against pathogenic stimuli and in its termination to limit tissue damage. This mechanism may explain at least in part the reported ability of NO to act in both a pro- and anti-inflammatory manner.

  3. Activation of endothelial nitric oxide synthase by a vanadium compound ameliorates pressure overload-induced cardiac injury in ovariectomized rats.

    PubMed

    Bhuiyan, Md Shenuarin; Shioda, Norifumi; Shibuya, Masatoshi; Iwabuchi, Yoshiharu; Fukunaga, Kohji

    2009-01-01

    We here investigated the effect of bis(1-oxy-2-pyridinethiolato) oxovanadium (IV), [VO(OPT)], against myocardial hypertrophy and cardiac functional recovery in pressure overload-induced hypertrophy in ovariectomized female rats and defined mechanisms underlying its cardioprotective action. Wistar rats subjected to bilateral ovariectomy were further treated with abdominal aortic stenosis. VO(OPT) (containing 1.25 and 2.50 mg of vanadium per kg) was administered orally once a day for 14 days starting from 2 weeks after aortic banding. Treatment with VO(OPT) significantly inhibited pressure overload-induced increase both in the heart weight:body weight ratio and the lung weight:body weight ratio. VO(OPT) also attenuated hypertrophy-induced impaired left ventricular end-diastolic pressure, left ventricular developed pressure, and left ventricular contractility (+/-dp/dt(max)). VO(OPT) treatment significantly restored pressure overload-induced impaired endothelial NO synthase activity with concomitant increased phosphorylation of endothelial NO synthase (Ser1179). Moreover, VO(OPT) treatment significantly restored pressure overload-induced reduced Akt activity, as indicated by increased phosphorylation at Ser473 and at Thr308. Treatment with VO(OPT) also secondarily inhibited calpastatin and dystrophin breakdown and decreased myosin light chain phosphorylation. Finally, VO(OPT) treatment significantly attenuated mortality after repeated isoproterenol administration in pressure overloaded-ovariectomized rats. Taken together, VO(OPT) attenuates cardiac myocytes hypertrophy in vivo in pressure overload-induced hypertrophy in ovariectomized rats and prevents the process from hypertrophy to heart failure. These effects are mediated by inhibition of calpastatin and dystrophin breakdown in addition to increased Akt and endothelial NO synthase activities.

  4. Hemoglobin Effects on Nitric Oxide Mediated Hypoxic Vasodilation.

    PubMed

    Rong, Zimei; Cooper, Chris E

    2016-01-01

    The brain responds to hypoxia with an increase in cerebral blood flow (CBF). However, such an increase is generally believed to start only after the oxygen tension decreases to a certain threshold level. Although many mechanisms (different vasodilator and different generation and metabolism mechanisms of the vasodilator) have been proposed at the molecular level, none of them has gained universal acceptance. Nitric oxide (NO) has been proposed to play a central role in the regulation of oxygen supply since it is a vasodilator whose production and metabolism are both oxygen dependent. We have used a computational model that simulates blood flow and oxygen metabolism in the brain (BRAINSIGNALS) to test mechanism by which NO may elucidate hypoxic vasodilation. The first model proposed that NO was produced by the enzyme nitric oxide synthase (NOS) and metabolized by the mitochondrial enzyme cytochrome c oxidase (CCO). NO production declined with decreasing oxygen concentration given that oxygen is a substrate for nitric oxide synthase (NOS). However, this was balanced by NO metabolism by CCO, which also declined with decreasing oxygen concentration. However, the NOS effect was dominant; the resulting model profiles of hypoxic vasodilation only approximated the experimental curves when an unfeasibly low K m for oxygen for NOS was input into the model. We therefore modified the model such that NO generation was via the nitrite reductase activity of deoxyhemoglobin instead of NOS, whilst keeping the metabolism of NO by CCO the same. NO production increased with decreasing oxygen concentration, leading to an improved reproduction of the experimental CBF versus PaO2 curve. However, the threshold phenomenon was not perfectly reproduced. In this present work, we incorporated a wider variety of oxygen dependent and independent NO production and removal mechanisms. We found that the addition of NO removal via oxidation to nitrate mediated by oxyhemoglobin resulted in the

  5. Nitric oxide inhibits the secretion of T-helper 1- and T-helper 2-associated cytokines in activated human T cells.

    PubMed Central

    Bauer, H; Jung, T; Tsikas, D; Stichtenoth, D O; Frölich, J C; Neumann, C

    1997-01-01

    Mechanisms regulating the balance of T-helper 1 (Th1) and T-helper 2 (Th2) immune responses are of great interest as they may determine the outcome of allergic and infectious diseases. Recently, in mice, nitric oxide (NO), a powerful modulator of inflammation, has been reported to preferentially down-regulate Th1-mediated immune responses. In the present study, we investigated the effect of NO on the production of Th1- and Th2-associated cytokines by activated human T cells and human T-cell clones. Cytokine secretion was measured in the presence of the NO-donating agents 3-morpholinosydnonimine (SIN-1) and S-nitroso-N-acetylpenicillamine (SNAP). Both NO-donors markedly inhibited the release of interferon-gamma (IFN-gamma), interleukin-2 (IL-2), IL-5, IL-10 and IL-4 by anti-CD3 activated T cells. A preferential inhibition of Th1-associated cytokines was not observed. Neither was nitrite found in the supernatants of activated T cells, nor was specific mRNA for inducible and constitutive NO synthase detectable, indicating that T cells themselves did not contribute to the observed effect of the NO donors. Costimulation with anti-CD28 monoclonal antibodies (mAb) prevented SIN-1/SNAP-mediated down-regulation of cytokine production only in part. In contrast, when T cells were stimulated by phorbol-ester and ionomycin, they were refractory to SIN-1-induced inhibition of cytokine production. When SIN-1 was added after the onset of anti-CD3 stimulation, the inhibitory effect was found to be less pronounced, indicating that SIN-1 may interfere with early signal transduction events. The addition of superoxide dismutase (SOD) and catalase did not restore the effects of SIN-1, demonstrating that the inhibition of cytokines was due to NO and not to oxygen intermediates. Furthermore, 8-Br-cGMP-mediated increase of intracellular cGMP caused the same pattern of cytokine inhibition as observed with SIN-1 and SNAP. Using a single cell assay, these agents were shown to reduce the

  6. Compositional variation among black tea across geographies and their potential influence on endothelial nitric oxide and antioxidant activity.

    PubMed

    Dias, Paul Mark; Changarath, Jayashree; Damodaran, Anita; Joshi, Manoj Kumar

    2014-07-16

    Black tea (C. sinensis) consumption is well associated with enhanced endothelial function (EF) and reduced cardiovascular (CV) risk. This clinical end benefit is endorsed to flavonoids in tea. The black tea flavonoid composition varies across geographies and may impact its health benefits. Moreover, the underlying functional species and a precise working mechanism responsible for the observed health benefit also remain to be investigated. In this Article, we investigated the effect of black teas from various geographies (WoBTs) on different working mechanisms (antioxidant potential and endothelial function) proposed to influence certain risk factors of CVH, in vitro. Pearson correlation analysis showed that the antioxidant benefits are fairly influenced by majority of tea actives such as catechins, theaflavins, thearubigins, and phenolic acids, while NO potentiating effects are mainly regulated by catechins in black tea. The data also suggest that the net vascular function benefit of black tea is majorly influenced by NO enhancement, while mildly contributed by its antioxidant benefit.

  7. Role of nitric oxide in cellular iron metabolism.

    PubMed

    Kim, Sangwon; Ponka, Prem

    2003-03-01

    Iron regulatory proteins (IRP1 and IRP2) control the synthesis of transferrin receptors (TfR) and ferritin by binding to iron-responsive elements (IREs) which are located in the 3' untranslated region (UTR) and the 5' UTR of their respective mRNAs. Cellular iron levels affect binding of IRPs to IREs and consequently expression of TfR and ferritin. Moreover, NO*, a redox species of nitric oxide that interacts primarily with iron, can activate IRP1 RNA-binding activity resulting in an increase in TfR mRNA levels. We have shown that treatment of RAW 264.7 cells (a murine macrophage cell line) with NO+ (nitrosonium ion, which causes S-nitrosylation of thiol groups) resulted in a rapid decrease in RNA-binding of IRP2, followed by IRP2 degradation, and these changes were associated with a decrease in TfR mRNA levels. Moreover, we demonstrated that stimulation of RAW 264.7 cells with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) increased IRP1 binding activity, whereas RNA-binding of IRP2 decreased and was followed by a degradation of this protein. Furthermore, the decrease of IRP2 binding/protein levels was associated with a decrease in TfR mRNA levels in LPS/IFN-gamma-treated cells, and these changes were prevented by inhibitors of inducible nitric oxide synthase. These results suggest that NO+-mediated degradation of IRP2 plays a major role in iron metabolism during inflammation.

  8. The production of nitric oxide by marine ammonia-oxidizing archaea and inhibition of archaeal ammonia oxidation by a nitric oxide scavenger.

    PubMed

    Martens-Habbena, Willm; Qin, Wei; Horak, Rachel E A; Urakawa, Hidetoshi; Schauer, Andrew J; Moffett, James W; Armbrust, E Virginia; Ingalls, Anitra E; Devol, Allan H; Stahl, David A

    2015-07-01

    Nitrification is a critical process for the balance of reduced and oxidized nitrogen pools in nature, linking mineralization to the nitrogen loss processes of denitrification and anammox. Recent studies indicate a significant contribution of ammonia-oxidizing archaea (AOA) to nitrification. However, quantification of the relative contributions of AOA and ammonia-oxidizing bacteria (AOB) to in situ ammonia oxidation remains challenging. We show here the production of nitric oxide (NO) by Nitrosopumilus maritimus SCM1. Activity of SCM1 was always associated with the release of NO with quasi-steady state concentrations between 0.05 and 0.08 μM. NO production and metabolic activity were inhibited by the nitrogen free radical scavenger 2-phenyl-4,4,5,5,-tetramethylimidazoline-1-oxyl-3-oxide (PTIO). Comparison of marine and terrestrial AOB strains with SCM1 and the recently isolated marine AOA strain HCA1 demonstrated a differential sensitivity of AOB and AOA to PTIO and allylthiourea (ATU). Similar to the investigated AOA strains, bulk water column nitrification at coastal and open ocean sites with sub-micromolar ammonia/ammonium concentrations was inhibited by PTIO and insensitive to ATU. These experiments support predictions from kinetic, molecular and biogeochemical studies, indicating that marine nitrification at low ammonia/ammonium concentrations is largely driven by archaea and suggest an important role of NO in the archaeal metabolism.

  9. Nitric Oxide Catalysis of Diazene E/Z Isomerization.

    PubMed

    Bohle, D Scott; Rosadiuk, Kristopher A

    2015-08-01

    Nitric oxide is an efficient catalyst for the cis-trans (E/Z) isomerization of diazenes. We compare the effect of room temperature solutions bearing low concentrations of nitric oxide, nitrogen dioxide, or oxygen on the rate of cis-trans isomerization, CTI, of the alkene bond in stilbene and on the azo double bond in azobenzene, as well as in four azo derivatives as measured by UV-vis spectroscopy. These rate enhancements can be as large as 3 orders of magnitude for azobenzene in solution. A mechanism is proposed where catalysis is promoted by the interaction of the nitric oxide with the diazene nitrogen lone pairs. Density functional theory, B3LYP/6-311++g** suggests that the binding of NO to the diazene should be weak and reversible but that its NO adduct has an E/Z isomerization barrier of 7.5 kcal/mol.

  10. Nitric oxide synthase in cat brain: cofactors--enzyme-substrate interaction.

    PubMed

    Côté, J F; Roberge, A G

    1996-01-01

    Nitric oxide, derived from L-arginine by the enzyme nitric oxide synthase, is an activator of the soluble guanylate cyclase and a cellular messenger. This work demonstrates that, in cat brain, the neuronal constitutive nitric oxide synthase activity is a) NADPH/calcium dependent, b) independent upon exogenous calmodulin in crude brain supernatant, c) significantly enhanced by exogenous FAD and tetrahydrobiopterin (Vmax: 118 instead of 59.4 pmol of citrulline formed .mg of prot.-1 min-1, d) inhibited by calcium chelators and calmodulin antagonist, and e) present in several neuroanatomical structures. Moreover, the Km value for L-arginine was of 11 microM instead of 41 microM in the presence of FAD and tetrahydrobiopterin in the incubation mixture, thus demonstrating that these cofactors are able to stabilize the enzyme-substrate interactions.

  11. Nitric oxide-cyclic GMP signaling in stem cell differentiation

    PubMed Central

    Mujoo, Kalpana; Krumenacker, Joshua S.; Murad, Ferid

    2011-01-01

    The nitric oxide-cyclic GMP (NO-cGMP) pathway mediates important physiological functions associated with various integrative body systems including the cardiovascular and nervous systems. Furthermore, NO regulates cell growth, survival, apoptosis, proliferation and differentiation at the cellular level. To understand the significance of the NO-cGMP pathway in development and differentiation, studies have been conducted both in developing embryos and stem cells. Manipulation of the NO-cGMP pathway by employing activators and inhibitors as pharmacological probes and/or genetic manipulation of NO signaling components has implicated the involvement of this pathway in regulation of stem cell differentiation. This review will focus on some of the work pertaining to the role of NO-cGMP in differentiation of stem cells into cells of various lineages particularly into myocardial cells and stem cell based therapy. PMID:22019632

  12. Nitric oxide signaling in aluminum stress in plants.

    PubMed

    He, Huyi; Zhan, Jie; He, Longfei; Gu, Minghua

    2012-07-01

    Nitric oxide (NO) is a ubiquitous signal molecule involved in multiple plant responses to environmental stress. In the recent years, the regulating role of NO on heavy metal toxicity in plants is realized increasingly, but knowledge of NO in alleviating aluminum (Al) toxicity is quite limited. In this article, NO homeostasis between its biosynthesis and elimination in plants is presented. Some genes involved in NO/Al network and their expressions are also introduced. Furthermore, the role of NO in Al toxicity and the functions in Al tolerance are discussed. It is proposed that Al toxicity may disrupt NO homeostasis, leading to endogenous NO concentration being lower than required for root elongation in plants. There are many evidences that pointed out that the exogenous NO treatments improve Al tolerance in plants through activating antioxidative capacity to eliminate reactive oxygen species. Most of the work with respect to NO regulating pathways and functions still has to be done in the future.

  13. Nitric oxide counters ethylene effects on ripening fruits

    PubMed Central

    Manjunatha, Girigowda; Gupta, Kapuganti J.; Lokesh, Veeresh; Mur, Luis AJ; Neelwarne, Bhagyalakshmi

    2012-01-01

    Ethylene plays a key role in promoting fruit ripening, so altering its biosynthesis/signaling could be an important means to delay this process. Nitric oxide (NO)-generated signals are now being shown to regulate ethylene pathways. NO signals have been shown to transcriptionally repress the expression of genes involved in ethylene biosynthesis enzymes and post-translationally modify methionine adenosyl transferase (MAT) activity through S-nitrosylation to reduce the availably of methyl groups required to produce ethylene. Additionally, NO cross-talks with plant hormones and other signal molecules and act to orchestrate the suppression of ethylene effects by modulating enzymes/proteins that are generally triggered by ethylene signaling at post-climacteric stage. Thus, medication of endogenous NO production is suggested as a strategy to postpone the climacteric stage of many tropical fruits. PMID:22499176

  14. Nitric oxide evoked p53-accumulation and apoptosis.

    PubMed

    Brüne, Bernhard; Schneiderhan, Nicole

    2003-04-01

    The tumor suppressor p53 accumulates under conditions of cellular stress and affects cell cycle progression and/or apoptosis. This has been exemplified for endogenously produced or exogenously supplied nitric oxide (NO) and thus accounts at least in part for cell destructive signaling qualities of this bioactive molecule and/or derived reactive nitrogen species. However, detailed mechanisms of toxicity and pathways of cell demise remain to be elucidated. Establishing that NO-treatment left the ubiquitination and the p53-Mdm2 interaction intact may point to an impaired nuclear-cytoplasmic shuttling to account for p53 stabilization. This was verified by heterokaryon analysis. We conclude that attenuated nuclear export contributes to stabilization and activation of p53 under the influence of NO.

  15. Nitric Oxide Regulates Neurogenesis in the Hippocampus following Seizures.

    PubMed

    Carreira, Bruno P; Santos, Daniela F; Santos, Ana I; Carvalho, Caetana M; Araújo, Inês M

    2015-01-01

    Hippocampal neurogenesis is changed by brain injury. When neuroinflammation accompanies injury, activation of resident microglial cells promotes the release of inflammatory cytokines and reactive oxygen/nitrogen species like nitric oxide (NO). In these conditions, NO promotes proliferation of neural stem cells (NSC) in the hippocampus. However, little is known about the role of NO in the survival and differentiation of newborn cells in the injured dentate gyrus. Here we investigated the role of NO following seizures in the regulation of proliferation, migration, differentiation, and survival of NSC in the hippocampus using the kainic acid (KA) induced seizure mouse model. We show that NO increased the proliferation of NSC and the number of neuroblasts following seizures but was detrimental to the survival of newborn neurons. NO was also required for the maintenance of long-term neuroinflammation. Taken together, our data show that NO positively contributes to the initial stages of neurogenesis following seizures but compromises survival of newborn neurons.

  16. Reaction between nitric oxide and ozone in solid nitrogen

    NASA Technical Reports Server (NTRS)

    Lucas, D.; Pimentel, G. C.

    1979-01-01

    Nitrogen dioxide, NO2, is produced when nitric oxide, NO, and ozone, O3, are suspended in a nitrogen matrix at 11-20 K. The NO2 is formed with first-order kinetics, a 12 K rate constant of (1.4 + or - 0.2) x 0.00001/sec, and an apparent activation energy of 106 + or - 10 cal/mol. Isotopic labeling, variation of concentrations, and cold shield experiments show that the growth of NO2 is due to reaction between ozone molecules and NO monomers, and that the reaction is neither infrared-induced nor does it seem to be a heavy atom tunneling process. Reaction is attributed to nearest-neighbor NO.O3 pairs probably held in a specific orientational relationship that affects the kinetic behavior. When the temperature is raised, more such reactive pairs are generated, presumably by local diffusion. Possible mechanisms are discussed.

  17. Strategies to increase nitric oxide signalling in cardiovascular disease.

    PubMed

    Lundberg, Jon O; Gladwin, Mark T; Weitzberg, Eddie

    2015-09-01

    Nitric oxide (NO) is a key signalling molecule in the cardiovascular, immune and central nervous systems, and crucial steps in the regulation of NO bioavailability in health and disease are well characterized. Although early approaches to therapeutically modulate NO bioavailability failed in clinical trials, an enhanced understanding of fundamental subcellular signalling has enabled a range of novel therapeutic approaches to be identified. These include the identification of: new pathways for enhancing NO synthase activity; ways to amplify the nitrate-nitrite-NO pathway; novel classes of NO-donating drugs; drugs that limit NO metabolism through effects on reactive oxygen species; and ways to modulate downstream phosphodiesterases and soluble guanylyl cyclases. In this Review, we discuss these latest developments, with a focus on cardiovascular disease.

  18. Nitric oxide and biopterin in depression and stress.

    PubMed

    van Amsterdam, J G; Opperhuizen, A

    1999-01-18

    Depression has been hypothesized to be related to the reduced biosynthesis of neurotransmitters such as serotonin, noradrenalin and dopamine. Much past research has also been devoted to dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis in depression. The present article reviews the evidence linking tetrahydrobiopterin, a co-factor in the biosynthesis of neurotransmitters, and nitric oxide, an apparent neuroendocrine modulator of the HPA axis, to the immune system and to neuronal control within affective disorder and stress. On the basis of this review, it is suggested that future psychoneuroimmunological research should more fully explore the possible role of tetrahydrobiopterin and nitric oxide in depressive disorders. PMID:10195314

  19. Nitric Oxide Production Inhibition and Anti-Mycobacterial Activity of Extracts and Halogenated Sesquiterpenes from the Brazilian Red Alga Laurencia Dendroidea J. Agardh

    PubMed Central

    Biá Ventura, Thatiana Lopes; da Silva Machado, Fernanda Lacerda; de Araujo, Marlon Heggdorne; de Souza Gestinari, Lísia Mônica; Kaiser, Carlos Roland; de Assis Esteves, Francisco; Lasunskaia, Elena B.; Soares, Angélica Ribeiro; Muzitano, Michelle Frazão

    2015-01-01

    Background: Red algae of the genus Laurencia J. V. Lamouroux are a rich source of secondary metabolites with important pharmacological activities such as anti-tumoral, anti-inflammatory, anti-fungal, anti-viral, anti-leishmanial, anti-helminthic, anti-malarial, anti-trypanosomal, anti-microbial as well as anti-bacterial against Mycobacterium tuberculosis. Objective: In the present study, we evaluated the inhibition of nitric oxide (NO) and tumor necrosis factor-α production and the anti-mycobacterial activity of crude extracts from the red Alga Laurencia dendroidea (from the South-Eastern coast of Brazil). Halogenated sesquiterpenes elatol (1), obtusol (2) and cartilagineol (3), previously isolated from this Alga by our group, were also studied. Materials and Methods: The lipo