Overproduction Of Nitric Oxide Research Articles

Protective effect of aminoguanidine against lipopolysaccharide-induced hepatotoxicity and liver dysfunction in rat

Lipopolysaccharide (LPS) as the major component of the outer membrane of Gram-negative bacteria activates macrophages to produce a high level of pro-inflammatory cytokines which is considered as a cause of liver dysfunction. Overproduction of nitric oxide (NO) has been suggested to have a role in hepatic injury. The aim of the present study was to explore the protective effects of aminoguanidine (AG) as inducible nitric oxide synthase (iNOS) inhibitor against LPS -induced liver dysfunction in rat. The animals were divided into five groups: (1) control (2) LPS (3) LPS-AG50, (4) LPS-AG100 and (5) LPS-AG150. LPS (1 mg/kg) was injected for 5 weeks and AG (50, 100 and 150 mg/kg) was administered 30 min before LPS. Drugs were injected intraperitoneally. LPS induced liver dysfunction presented by increasing the serum level of alkaline phosphatase (ALK-P), alanine aminotransferase (ALT), aspartate aminotransferase (AST). Pretreatment with AG restored harmful effects of LPS on liver function. In addition, LPS resulted in hepatotoxicity, accompanied by enhancing the level of interleukin (IL)-6, malondialdehyde (MDA) and nitric oxide (NO) metabolites and decreasing the content of total thiol groups and superoxide dismutase (SOD) and catalase (CAT) activity. Injection of AG before LPS attenuated LPS-induced hepatotoxicity through decreasing the level of IL-6, MDA and NO metabolites and increasing total thiols and SOD and CAT activity. Considering the protective effect of AG which was seen in the present study, it seems that increased levels of NO due to activation of iNOS has a role in LPS-induced hepatic injury.

THE CHANGES IN DYNAMICS OF ORNITHINE CYCLE COMPONENTS LEVELS DURING THE ACUTE PERIOD OF POLYTRAUMA

Introduction: Polytrauma or multiple organ damage is associated with shock and lead to systemic inflammation, oxidative stress and endothelial dysfunction. A severe mechanical injury causes an increased proinflammatory mediators and cytokines levels. Among them, the overproduction of nitric oxide and its oxidation products play a key role in tissue damage. The aim: To evaluate the changes in dynamics of some ornithine cycle components levels during acute period of polytrauma. Materials and methods: We measured standard biomechanical parameters and serum levels of NO, sum of nitrite and nitrate (NOx), L-arginine, arginase, and peroxynitrite. According to the ISS, the study included patients with moderate (n=15) to severe (n=15) polytrauma. Results: In 24 hours after polytrauma on the background of intensive care, it was observed significant increasing of NO, NOx, and arginase levels (severe cases) with decreasing of L-arginine and peroxynitrite levels. Conclusions: Elevated NO and NOx serum levels in patients with polytrauma is associated with increasing of arginase activity with decreasing of L-arginine and peroxynitrite levels on the background of intensive care.

Preventive effect of oligonol on nitric oxide and reactive oxygen species production through regulation of nuclear factor kappa B signaling pathway in RAW 264.7 macrophage cells against sodium nitroprusside.

Oligonol, a low-molecular weight polyphenol isolated from lychee fruit, has been shown to possess beneficial properties, including anti-oxidative, anti-diabetic, and hepatoprotective properties in vitro and in vivo. This study was performed to investigate the anti-inflammatory effects of oligonol using sodium nitroprusside (SNP)-stimulated RAW 264.7 macrophage cells. Our results demonstrated that exposure of SNP to RAW 264.7 cells significantly decreased cell viability, and increased nitric oxide (NO) and reactive oxygen species (ROS) production. However, treatment with oligonol inhibited cell death and suppressed the over-production of NO and ROS induced by SNP in a dose-dependent manner. Consistent with these findings, oligonol significantly downregulated the mRNA levels of pro-inflammatory mediators, inducible nitric oxide synthase and cyclooxygenase-2, when compared with the SNP-treated control group. Furthermore, suppression of nuclear factor-κB (NF-κB) activation was also observed after treatment with oligonol in RAW 264.7 macrophage cells. These results suggest that oligonol attenuated SNP-induced oxidative stress and inflammatory responses via regulation of the NF-κB signalling pathway. On the basis of such potent anti-oxidant and anti-inflammatory properties, we propose that oligonol may contribute in the prevention and treatment of inflammation-related disorders.

Taurine-Rich-Containing Hot Water Extract of Loliolus Beka Gray Meat Scavenges Palmitate-Induced Free Radicals and Protects Against DNA Damage in Insulin Secreting β-Cells.

The loss of pancreatic β-cells plays a central role in the pathogenesis of both type 1 and type 2 diabetes, and many studies have been focused on ways to improve glucose homeostasis by preserving, expanding and improving the function of β-cell. Elevated levels of free fatty acids such as palmitate might contribute to the loss of β-cells. A marine squid, Loliolus beka has long been used as a food in Korea, China, Japan and Europe due to its tender meat and high taurine content. Here, we investigated the protective effects of a hot water extract of Loliolus beka meat (LBM) against palmitate toxicity in Ins-1 cells, a rat β-cell line. Treatment with LBM extract protected against palmitate-induced cytotoxicity and scavenged overproduction of nitric oxide, alkyl, and hydroxyl radicals. In addition, LBM extract protected against palmitate-induced DNA damage and β-cell dysfunction. These findings suggest that LBM protects pancreatic β-cells from palmitate-induced damage. LBM could be a potential therapeutic functional food for diabetes.

Acetylation of polysaccharide from Morchella angusticeps peck enhances its immune activation and anti-inflammatory activities in macrophage RAW264.7 cells

Morchella angusticeps Peck has been recognized as a resource of nutraceuticals and drug discovery. Three acetylated polysaccharides (Ac-PMEP1-3) with appropriate degree of substitution were obtained from Morchella angusticeps Peck, chemically characterized, and cultured with macrophage RAW264.7 cells to evaluate their immune activation and anti-inflammatory activities. Results of ultraviolet–visible spectroscopy and fourier-transform infrared showed these modifications were successful. Compared with the control group, PMEP and Ac-PMEP1-3 enhanced cell proliferation and the production of nitric oxide and tumor necrosis factor-α of RAW264.7 macrophages (cultured without lipopolysaccharide). Compared with PMEP, Ac-PMEP3 enhanced cell viability and NO production by inducing the degradation of cytoplasmic IκBα and nuclear translocation of NF-κB subunit p65 as well as the expression of iNOS and phosphorylated-p38. Moreover, in lipopolysaccharide-stimulated RAW264.7 macrophages, Ac-PMEP3 showed a stronger ability to suppress the overproduction of nitric oxide and tumor necrosis factor-α by down-regulating the level of nuclear NF-κB p65, iNOS, and phosphorylated-p38 and inhibiting the degradation of cytoplasmic IκBα. Therefore, Ac-PMEP enhanced immune activation and anti-inflammatory activities via nuclear factor κB and p38/mitogen-activated protein kinase signaling pathways.

Chlorpyrifos- and Dichlorvos-Induced Oxidative and Neurogenic Damage Elicits Neuro-Cognitive Deficits and Increases Anxiety-Like Behavior in Wild-Type Rats.

The execution of agricultural activities on an industrial scale has led to indiscriminate deposition of toxic xenobiotics, including organophosphates, in the biome. This has led to intoxication characterized by deleterious oxidative and neuronal changes. This study investigated the consequences of oxidative and neurogenic disruptions that follow exposure to a combination of two organophosphates, chlorpyrifos (CPF) and dichlorvos (DDVP), on neuro-cognitive performance and anxiety-like behaviors in rats. Thirty-two adult male Wistar rats (150–170 g) were randomly divided into four groups, orally exposed to normal saline (NS), DDVP (8.8 mg/kg), CPF (14.9 mg/kg), and DDVP + CPF for 14 consecutive days. On day 10 of exposure, anxiety-like behavior and amygdala-dependent fear learning were assessed using open field and elevated plus maze paradigms, respectively, while spatial working memory was assessed on day 14 in the Morris water maze paradigm, following three training trials on days 11, 12, and 13. On day 15, the rats were euthanized, and their brains excised, with the hippocampus and amygdala removed. Five of these samples were homogenized and centrifuged to analyze nitric oxide (NO) metabolites, total reactive oxygen species (ROS), and acetylcholinesterase (AChE) activity, and the other three were processed for histology (cresyl violet stain) and proliferative markers (Ki67 immunohistochemistry). Marked (p ≤0.05) loss in body weight, AChE depletion, and overproduction of both NO and ROS were observed after repeated exposure to individual and combined doses of CPF and DDVP. Insults from DDVP exposure appeared more severe owing to the observed greater losses in the body weights of exposed rats. There was also a significant (p ≤0.05) effect on the cognitive behaviors recorded from the exposed rats, and these deficits were related to the oxidative damage and neurogenic cell loss in the hippocampus and the amygdala of the exposed rats. Taken together, these results provided an insight that oxidative and neurogenic damage are central to the severity of neuro-cognitive dysfunction and increased anxiety-like behaviors that follow organophosphate poisoning.

Blood levels of nitric oxide and DNA breaks assayed in whole blood and isolated peripheral blood mononucleated cells in patients with multiple sclerosis

Oxidative stress, especially overproduction of nitric oxide (NO), is considered to be one of the crucial factors in the pathogenesis of multifactorial multiple sclerosis (MS). DNA breaks could be one of the consequences of oxidative stress; however, data on DNA breakage in MS are very few and contradictory. There are no data on direct measurements of NO production in the blood of MS patients.The goal of this study was to determine the level of single-stranded DNA breaks in whole blood or isolated peripheral blood mononuclear cells (PBMNCs) by means of alkaline single cell gel electrophoresis (comet assay) and to evaluate production of NO in the human blood by applying electron paramagnetic resonance (EPR) spectroscopy.Groups of healthy subjects and MS patients were enrolled in the study. Blood samples were obtained by vein puncture and divided in aliquots for the analysis of the whole blood and isolated PBMNC with comet assay. Alkaline single cell gel electrophoresis was performed on whole blood and isolated PBMNC samples of 28 patients and 15 controls. A separate blood sample was mixed with a spin-trap, frozen in liquid nitrogen and used for NO detection by EPR; 22 MS patients and 22 controls were tested.A statistically significant increase in the level of DNA breakage was observed in specimens taken from MS patients compared to healthy persons. The level of DNA damage in whole blood and PBMNCs of the same group was similar. NO production was significantly higher in the blood of MS patients.

Synthesis and In Vitro Anti-inflammatory Activity of C20 Epimeric Ocotillol-Type Triterpenes and Protopanaxadiol.

Ginseng is a perennial herb that contains various medicinal substances. The major active constituents of ginseng are ginsenosides, which have multifarious biological activities. Some pharmacological activities are closely dependent on the stereoisomers derived from the configuration at C20. In this study, the in vitro anti-inflammatory activity of C20 epimeric ocotillol-type triterpenes (2, 3, 9: , and 10: ) and protopanaxadiol [20(S/R)-protopanaxadiol] were investigated. Epimers 2: and 3: were prepared starting from 20(S)-protopanaxadiol. Epimers 9: and 10: were synthesized from 20(R)-3-acetylprotopanaxadiol (7: ). The anti-inflammatory activity of 2, 3, 9, 10: , 20(S)-protopanaxadiol, and 20(R)-protopanaxadiol was evaluated in cultured mouse macrophage RAW 264.7 cells. The MTT assay was used to measure the cytotoxicity. RAW 264.7 cells were stimulated by lipopolysaccharide to release the inflammatory mediators nitric oxide, prostaglandin E2, TNF-α, and interleukin-6 and anti-inflammatory mediator interleukin-10. The effect of the compounds on the overproduction of nitric oxide, prostaglandin E2, TNF-α, interleukin-6, and interleukin-10 was determined using Griess and ELISA methods. The results demonstrated that the in vitro anti-inflammatory activities of C20 epimeric ocotillol-type triterpenes and protopanaxadiol were different. Both the 20S-epimers (2: and 3: ) and 20R-epimers (9: and 10: ) inhibited the release of inflammatory mediator nitric oxide, while mainly the 20S-epimers inhibited the release of inflammatory mediator prostaglandin E2, and the 20R-epimers inhibited the release of inflammatory cytokine TNF-α. Both the 20S-epimers [2, 3: , and 20(S)-protopanaxadiol] and 20R-epimers [9, 10: , and 20(R)-protopanaxadiol] inhibited the release of inflammatory cytokine interleukin-6, but mainly the 20S-epimers [2, 3: , and 20(S)-protopanaxadiol] increased the release of anti-inflammatory mediator interleukin-10.

Azasulfurylpeptide Modulation of CD36-Mediated Inflammation Without Effect on Neovascularization.

Modulation of the cluster of differentiation-36 receptor (CD36) has proven promising for dampening pro-inflammatory macrophage signaling. For example, azapeptides (e.g., 1 and 2) bind CD36 selectively with high affinity, mitigate Toll-like receptor (TLR) agonist-induced overproduction of nitric oxide (NO), and reduce pro-inflammatory cytokine and chemokine production in macrophages. Moreover, semicarbazides 1 and 2 inhibit microvascular sprouting mediated through CD36 in the choroid explant. Seeking a selective CD36 modulator that mediated inflammation without influencing neovascularization, a set of azasulfurylpeptides (e.g., 3a–e) were synthesized in which the semicarbazide was replaced by an N-aminosulfamide residue using a novel solid-phase approach. Notably, azasulfurylpeptide 3c diminished selectively CD36-mediated TLR-2-triggered inflammatory response without affecting neovascularization. Subtle chemical modification at the peptide backbone from a carbonyl to a sulfuryl residue has had a selective effect on biological activity providing a valuable probe for studying CD36 chemical biology.

Association of Dietary Nitrate Intake with the 15-Year Incidence of Age-Related Macular Degeneration

BackgroundDietary nitrate, found predominantly in green leafy vegetables and beetroot, is a precursor of nitric oxide. Under- or overproduction of nitric oxide is implicated in the etiology of several eye diseases. However, the potential influence of dietary nitrate intake on age-related macular degeneration (AMD) risk has not been assessed. ObjectiveTo investigate the temporal association between dietary nitrate intake (from both vegetable and nonvegetable sources) and the 15-year incidence of AMD, independent of potential confounders. DesignA longitudinal cohort study conducted from 1992-1994 to 2007-2009. Participants/settingThe Blue Mountains Eye Study is a population-based study of adults aged 49+ at baseline, from a region west of Sydney, Australia. At baseline, 2,856 participants with complete dietary data and AMD information were examined, and of these, 2,037 participants were re-examined 15 years later and thus included in incidence analysis. Main outcomes measuredIncidence of AMD (main outcome) was assessed from retinal photographs. Dietary intake was assessed using a semiquantitative food-frequency questionnaire. Nitrate intake from vegetables and nonvegetable sources was calculated by use of a validated comprehensive database. ResultsAfter adjusting for age, sex, smoking, energy intake, fish consumption, and AMD risk alleles (complement factor H and age-related maculopathy susceptibility-2 single nucleotide polymorphisms), participants in the third quartile compared with those in the first quartile (reference group) of total nitrate and total vegetable nitrate intake had reduced risk of incident early AMD: odds ratio (OR) 0.61 (95% CI 0.41 to 0.90) and OR 0.65 (95% CI 0.44 to 0.96), respectively. Significant associations were not observed between the fourth vs first quartile of total nitrate and vegetable nitrate intake with incident early AMD: OR 0.74 (95% CI 0.51 to 1.08) and OR 0.69 (95% CI 0.47 to 1.00), respectively. Nonsignificant associations were also observed with 15-year incidence of late AMD and total nonvegetable nitrate intake. ConclusionsThese novel findings could have important implications, if the association between total nitrate intake and vegetable nitrate intake and 15-year incidence of early AMD is confirmed in other observational or intervention studies.

Structural Basis for Isoform Selective Nitric Oxide Synthase Inhibition by Thiophene-2-carboximidamides.

The overproduction of nitric oxide in the brain by neuronal nitric oxide synthase (nNOS) is associated with a number of neurodegenerative diseases. Although inhibiting nNOS is an important therapeutic goal, it is important not to inhibit endothelial NOS (eNOS) because of the critical role played by eNOS in maintaining vascular tone. While it has been possible to develop nNOS selective aminopyridine inhibitors, many of the most potent and selective inhibitors exhibit poor bioavailability properties. Our group and others have turned to more biocompatible thiophene-2-carboximidamide (T2C) inhibitors as potential nNOS selective inhibitors. We have used crystallography and computational methods to better understand how and why two commercially developed T2C inhibitors exhibit selectivity for human nNOS over human eNOS. As with many of the aminopyridine inhibitors, a critical active site Asp residue in nNOS versus Asn in eNOS is largely responsible for controlling selectivity. We also present thermodynamic integration results to better understand the change in p Ka and thus the charge of inhibitors once bound to the active site. In addition, relative free energy calculations underscore the importance of enhanced electrostatic stabilization of inhibitors bound to the nNOS active site compared to eNOS.

Identification of \u03b2-carboline and canthinone alkaloids as anti-inflammatory agents but with different inhibitory profile on the expression of iNOS and COX-2 in lipopolysaccharide-activated RAW 264.7 macrophages

A compound library, which consists of 75 natural β-carboline-type or canthinone-type alkaloids from Simaroubaceae plants and their chemical synthetic analogues, was screened for the anti-inflammatory activity by inhibition of the overproduction of inflammatory mediator nitric oxide (NO) in lipopolysaccharide (LPS)-activated RAW 264.7 macrophage cells. Six compounds, namely, benzalharman (23), kumujian (27), 1-ethyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (37), 1-acetophenone-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (42), cathin-6-one (46), and 9-methoxy-cathin-6-one (57), exhibited significant inhibitory activity on the overproduction of NO with good dose dependency. Further investigation demonstrated that all of the six compounds down-regulated the high expression of inducible nitric oxide synthase (iNOS) protein. Among them, two canthinone-type alkaloids (46 and 57) potently down-regulated cyclooxygenase-2 (COX-2) protein expression in a dose-dependent manner and also inhibited the overproduction of inflammatory mediator prostaglandin E2 (PGE2). However, the β-carboline-type alkaloids (23, 27, 37, and 42) exhibited no obvious inhibition on the overproduction of PGE2 and the expression of COX-2 protein. The results suggested that β-carboline-type alkaloids and canthinone-type alkaloids may exert an anti-inflammatory effect through different mechanism.

Endogenous nitric oxide and hydrogen peroxide detection in indole-3-butyric acid-induced adventitious root formation in Camellia sinensis

Nitric oxide (NO) and hydrogen peroxide (H2O2) are essential signaling molecules with key roles in auxin induced adventitious root formation in many plants. However, whether they are the sole determinants for adventitious root formation is worth further study. In this study, endogenous NO and H2O2 were monitored in tea cutting with or without indole-3-butyric acid (IBA) treatment by using the fluorescent probes diaminofluorescein diacetate (DAF-2DA) and 2',7'-dichlorodihydrofluorescein diacetate (DCF-DA), respectively. The overproduction of NO and H2O2 was detected in the rooting parts of tea cuttings treated with or without IBA. But little NO and H2O2 was detected before the initiation phase of tea cuttings even with IBA treatment indicating that they might be not directly induced by IBA. Further carbon and nitrogen analysis found that the overproduction of NO and H2O2 were coincident with the consumption of soluble sugars and the assimilation of nitrogen. These results suggest that rooting phases should be taken into consideration with the hypothesis that auxin induces adventitious root formation via NO- and H2O2-dependent pathways and sink establishment might be a prerequisite for NO and H2O2 mediated adventitious root formation.

MicroRNA-155 Amplifies Nitric Oxide/cGMP Signaling and Impairs Vascular Angiotensin II Reactivity in Septic Shock.

Septic shock is a life-threatening clinical situation associated with acute myocardial and vascular dysfunction, whose pathophysiology is still poorly understood. Herein, we investigated microRNA-155-dependent mechanisms of myocardial and vascular dysfunction in septic shock. Prospective, randomized controlled experimental murine study and clinical cohort analysis. University research laboratory and ICU at a tertiary-care center. Septic patients, ICU controls, and healthy controls. Postmortem myocardial samples from septic and nonseptic patients. Ex vivo evaluation of arterial rings from patients undergoing coronary artery bypass grafting. C57Bl/6J and genetic background-matched microRNA-155 knockout mice. Two mouse models of septic shock were used. Genetic deletion and pharmacologic inhibition of microRNA-155 were performed. Ex vivo myographic studies were performed using mouse and human arterial rings. We identified microRNA-155 as a highly up-regulated multifunctional mediator of sepsis-associated cardiovascular dysfunction. In humans, plasma and myocardial microRNA-155 levels correlate with sepsis-related mortality and cardiac injury, respectively, whereas in murine models, microRNA-155 deletion and pharmacologic inhibition attenuate sepsis-associated cardiovascular dysfunction and mortality. MicroRNA-155 up-regulation in septic myocardium was found to be mostly supported by microvascular endothelial cells. This promoted myocardial microvascular permeability and edema, bioenergetic deterioration, contractile dysfunction, proinflammatory, and nitric oxide-cGMP-protein kinase G signaling overactivation. In isolate cardiac microvascular endothelial cells, microRNA-155 up-regulation significantly contributes to LPS-induced proinflammatory cytokine up-regulation, leukocyte adhesion, and nitric oxide overproduction. Furthermore, we identified direct targeting of CD47 by microRNA-155 as a novel mechanism of myocardial and vascular contractile depression in sepsis, promoting microvascular endothelial cell and vascular insensitivity to thrombospondin-1-mediated inhibition of nitric oxide production and nitric oxide-mediated vasorelaxation, respectively. Additionally, microRNA-155 directly targets angiotensin type 1 receptor, decreasing vascular angiotensin II reactivity. Deletion of microRNA-155 restored angiotensin II and thrombospondin-1 vascular reactivity in LPS-exposed arterial rings. Our study demonstrates multiple new microRNA-155-mediated mechanisms of sepsis-associated cardiovascular dysfunction, supporting the translational potential of microRNA-155 inhibition in human septic shock.

Recent Developments in Drug Design of NO-donor Hybrid Compounds.

The free radical nitric oxide (NO) is considered one of the most versatile endogenous molecules and is a crucial signalling molecule in numerous biochemistry pathways of the human body. NO is directly related to pathological processes and plays an important role in many different and interrelated physiological processes. In some cases, a depletion of NO or an attenuation of its effector system could exist as in hypertension, angina and impotence; in others, an overproduction of NO may be a major cause of damage, as in circulatory shock, sepsis, neurodegenerative disorders and inflammatory responses. By using certain functional groups present in molecules that already have potential therapeutic value, hybrid compounds, by means of inclusion of NO-donors (e.g., ester nitrates and nitrites, S-nitrosothiols, metal complexes, furoxans, oxadiazoles, diazeniumdiolates and NO nanoparticles), can be developed that have a NO release benefit along with maintaining the activity of the native drug. The objective of the design of NO-donor hybrid compounds is to achieve a balance between the release of therapeutic amounts of NO, especially in the site of action, and maintaining the native drug activity. This review explores some of the most promising recent advances in NO-donor drug development and addresses the challenges associated with NO as a therapeutic agent.

IDH2 Deficiency in Microglia Decreases the Pro-inflammatory Response via the ERK and NF-κB Pathways.

In various neuronal diseases, the activation of microglia contributes to the production of excessive neurotoxic factors, such as pro-inflammatory mediators. In particular, the overproduction of pro-inflammatory cytokines and nitric oxide (NO) has critical effects on the development of neurodegenerative diseases and gliomas in the brain. Recent studies have suggested that isocitrate dehydrogenase 2 (IDH2) plays a key role in inducing gliomas and neurodegeneration. IDH2 dysfunction has been linked to various cancers and neurodegenerative diseases associated with uncontrolled inflammatory responses, such as the excessive generation of pro-inflammatory cytokines. In this study, we demonstrate that IDH2 contributes to the regulation of pro-inflammatory mediators in microglia. The downregulation of IDH2 decreased the lipopolysaccharide (LPS)-induced pro-inflammatory response in BV-2 and primary microglial cells. Furthermore, IDH2 deficiency downregulated pro-inflammatory mediators via modulation of the ERK and NF-κB pathways. These results indicate that IDH2 is a potential target for the regulation of pro-inflammatory responses in LPS-activated microglial cells. Our findings also provide a basis for the development of new therapies for pro-inflammatory responses in dysfunction-associated neuronal diseases.

Anti-inflammatory action of ambuic acid, a natural product isolated from the solid culture of Pestalotiopsis neglecta, through blocking ERK/JNK mitogen-activated protein kinase signaling pathway.

Ambuic acid is an organic acid isolated from the solid culture of Pestalotiopsis neglecta, which is an endophytic fungus that widely exists in many species of plants. Ambuic acid has been reported to exert antimicrobial activity against Gram-positive bacterium. The aim of the present study was to investigate the inhibitory effect of ambuic acid on lipopolysaccharide (LPS)-induced inflammation in RAW264.7 macrophages. The results demonstrated that ambuic acid significantly suppressed the overproduction of nitric oxide (NO) and prostaglandin E2 (PGE2) in a dose-dependent manner. Furthermore, ambuic acid also inhibited the release of the proinflammatory cytokine interleukin-6 (IL-6) however, no inhibition of the release of tumor necrosis factor-α (TNF-α) was observed. Further investigations indicated that ambuic acid downregulated the LPS-induced high expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins, as well as inhibited the enzymatic activity of iNOS and COX-2. In addition, ambuic acid suppressed the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2) and c-Jun N-terminal kinase (JNK) induced by LPS. However, ambuic acid did not inhibit the phosphorylation of p38 mitogen-activated protein kinase (MAPK), the degradation of IκB-α protein or the nuclear translocation of nuclear transcription factor-κB (NF-κB) p65 subunit. These results suggested that ambuic acid may exert anti-inflammatory action by blocking the activation of the ERK/JNK MAPK signaling pathway, without the involvement of the p38 MAPK or NF-κB signaling pathways.

The antagonistic effect of selenium on cadmium-induced apoptosis via PPAR-γ/PI3K/Akt pathway in chicken pancreas

The animal experiment was preformed to investigate the roles of PPAR-γ/PI3K/Akt pathway in apoptosis triggered by cadmium (Cd) and in the antagonistic effects of selenium (Se) on Cd in the pancreas of chicken. The current study showed that Cd treatment obviously increased the accumulation of Cd and directly led to lower activities of amylase, trypsin and lipase in chicken pancreas. The expression of PPAR-γ, PI3K, and Akt was declined, whereas the level of Bax, Cyt C and caspase-3 were increased in Cd group. In the result of TUNEL assay and the histological examination, typical apoptosis characteristics in the pancreas of Cd group were confirmed. Cd group also showed high levels of inducible nitric oxide synthase (iNOS) activity and nitric oxide (NO) content in pancreas. However, those Cd-induced changes were obviously alleviated in Cd + Se group. Our study revealed that Cd could impact the pancreas function and induce the activation of Bax and the overproduction of NO via PPAR-γ/PI3K/Akt pathway to promote apoptosis in chicken pancreas. However, Se could reduce Cd accumulation and antagonize Cd-triggered apoptosis in chicken pancreas.

Zanamivir Diminishes Lung Damage in Influenza A Virus-infected Mice by Inhibiting Nitric Oxide Production.

Severe pulmonary influenza A virus (IAV) infection causes lung inflammation and expression of inducible nitric oxide synthase (iNOS), leading to overproduction of nitric oxide (NO). We studied whether zanamivir reduces pulmonary inflammation through inhibition of NO production in mice. We treated IAV-infected mice daily with intranasal zanamivir. Controls were infected and either placebo-treated or untreated, or not infected and placebo-treated. Mice were weighed daily. After euthanasia on day 3, lungs were excised and bronchoalveolar lavage was performed and fluid nitrite concentration was determined. Lungs were analyzed microscopically. iNOS and IAV RNA levels in lungs were assessed using quantitative reverse transcription-polymerase chain reaction (RT-qPCR). Mice undergoing zanamivir treatment had less weight loss, viral replication, and lung damage, as well as significant reductions of local NO and iNOS mRNA synthesis (p<0.05). Zanamivir is associated with an anti-inflammatory effect mediated through inhibition of NO production in IAV-infected mice.

Neuroprotective Effect of Alpha-Linolenic Acid against Aβ-Mediated Inflammatory Responses in C6 Glial Cell.

Therapeutic approaches for neurodegeneration, such as Alzheimer's disease (AD), have been widely studied. One of the critical hallmarks of AD is accumulation of amyloid beta (Aβ). Aβ induces neurotoxicity and releases inflammatory mediators or cytokines through activation of glial cell, and these pathological features are observed in AD patient's brain. The purpose of this study is to investigate the protective effect of alpha-linolenic acid (ALA) on Aβ25-35-induced neurotoxicity in C6 glial cells. Exposure of C6 glial cells to 50 μM Aβ25-35 caused cell death, overproduction of nitric oxide (NO), and pro-inflammatory cytokines release [interleukin (IL)-6 and tumor necrosis factor-α], while treatment of ALA increased cell viability and markedly attenuated Aβ25-35-induced excessive production of NO and those inflammatory cytokines. Inhibitory effect of ALA on generation of NO and cytokines was mediated by down-regulation of inducible nitric oxide synthase and cyclooxygenase-2 protein and mRNA expressions. In addition, ALA treatment inhibited reactive oxygen species generation induced by Aβ25-35 through the enhancement of the nuclear factor-erythroid 2-related factor-2 (Nrf-2) protein levels and subsequent induction of heme-oxygenase-1 (HO-1) expression in C6 glial cells dose- and time-dependently. Furthermore, the levels of neprilysin and insulin-degrading enzyme protein expressions, which contribute to degradation of Aβ, were also increased by treatment of ALA compared to Aβ25-35-treated control group. In conclusion, effects of ALA on Aβ degradation were shown to be mediated through inhibition of inflammatory responses and activation of antioxidative system, Nrf-2/HO-1 signaling pathway, in C6 glial cells. Our findings suggest that ALA might have the potential for therapeutics of AD.