scholarly journals Exendin-4 inhibits interleukin-1β-induced iNOS expression at the protein level, but not at the transcriptional and posttranscriptional levels, in RINm5F β-cells

2009 ◽  
Vol 202 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Jung-Hoon Kang ◽  
Seo-Yoon Chang ◽  
Hyun-Jong Jang ◽  
Dong-Bin Kim ◽  
Gyeong Ryul Ryu ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Inos Expression ◽  
Interleukin 1Β ◽  
Inos Mrna ◽  
Β Cells ◽  
Β Cell ◽  
Inos Protein ◽  
Inos Gene ◽  
Nitrite Production ◽  
Inos Promoter

Cytokines such as interleukin-1β (IL-1β) stimulate inducible nitric oxide synthase (iNOS) expression and nitric oxide overproduction leading to β-cell damage. Meanwhile, glucagon-like peptide-1 (GLP-1) and its potent analog exendin-4 (EX-4) were well known for β-cell proliferation. However, the protective mechanisms of GLP-1 in β-cells exposed to cytokines were not fully elucidated. Therefore, the effects of EX-4 on the IL-1β-induced iNOS gene expression were investigated employing RINm5F β-cells. EX-4 inhibited IL-1β-induced iNOS protein expression and nitrite production. However, northern blot and promoter analyses showed that EX-4 failed to inhibit IL-1β-induced iNOS mRNA expression and iNOS promoter activity. By electrophoretic mobility shift assay (EMSA), EX-4 did not alter the binding activity of NF-κB to the iNOS promoter. Consistent with the EMSA result, EX-4 did not inhibit nuclear translocation of p65. We also tested the effect of EX-4 on iNOS mRNA stability. Actinomycin D chase experiments showed that EX-4 did not affect the decay rate of iNOS mRNA and the promoter assay using the construct containing 3′-untranslated region of iNOS showed that EX-4 did not alter the stability of iNOS mRNA. Meanwhile, forskolin significantly inhibited IL-1β-induced iNOS protein, which was reversed by H-89, a protein kinase A (PKA) inhibitor. Moreover, EX-4 pretreatment restored IL-1β-induced decrease in cAMP toward control level. Additionally, the cycloheximide chase study demonstrated that EX-4 significantly accelerated iNOS protein degradation. We therefore concluded that EX-4 inhibited IL-1β-induced iNOS protein and nitrite production via cAMP/PKA system irrespective of both transcriptional and posttranscriptional mechanisms of iNOS gene, and this inhibitory effect of EX-4 appears to be regulated at posttranslational level.

IL-1β hampers glucose-stimulated insulin secretion in Cohen diabetic rat islets through mitochondrial cytochrome c oxidase inhibition by nitric oxide

2014 ◽  
Vol 306 (6) ◽  
pp. E648-E657 ◽  
Author(s):  
Sarah Weksler-Zangen ◽  
Genya Aharon-Hananel ◽  
Carmit Mantzur ◽  
Tzemach Aouizerat ◽  
Ewa Gurgul-Convey ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Insulin Secretion ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Potassium Cyanide ◽  
Inos Expression ◽  
Interleukin 1Β ◽  
Atp Content ◽  
Regular Diet ◽  
Nitrite Production

A high-sucrose, low-copper-diet (HSD) induces inhibition of glucose-sensitive rats (CDs) but not Cohen diabetes-resistant rats (CDr). Copper-supplemented HSD increased activity of the copper-dependent mitochondrial respiratory chain enzyme cytochrome c oxidase (COX) and reversed hyperglycemia. This study examined the mechanism by which interleukin-1β modulates GSIS and the role of COX in this process. We measured COX activity, ATP content, GSIS, iNOS expression, and nitrite production with and without IL-1β, Nω-nitro-l-arginine, copper, or potassium cyanide in isolated islets of CDs and CDr fed different diets. We found reduced COX activity, ATP content, and GSIS in isolated islets of CDs rats fed a regular diet. These were severely reduced following HSD and were restored to regular diet levels on copper-supplemented HSD ( P < 0.01 vs. CDr islets). Potassium cyanide chemically reduced COX activity, decreasing GSIS and thus reinforcing the link between islet COX activity and GSIS. Interleukin-1β (2.5 U/ml) reduced GSIS and COX activity in CDs islets. Exposure to 10 U/ml interleukin-1β decreased GSIS and COX activity in both CDs and CDr islets, inducing a similar nitrite production. Nevertheless, the effect on GSIS was more marked in CDs islets. A significant iNOS expression was detected in CDs on the HSD diet, which was reduced by copper supplementation. Nω-nitro-l-arginine and copper prevented the deleterious effect of interleukin-1β on COX activity and GSIS. We conclude that reduced islet COX activity renders vulnerability to GSIS inhibition on low-copper HSD through two interrelated pathways: 1) by further reducing the activity of COX that is essential for β-cell ATP-production and insulin secretion and 2) by inducing the expression of iNOS and nitric oxide-mediated COX inhibition. We suggest that islet COX activity must be maintained above a critical threshold to sustain adequate GSIS with exposure to low-copper HSD.

scholarly journals Subtilase Cytotoxin Enhances Escherichia coli Survival in Macrophages by Suppression of Nitric Oxide Production through the Inhibition of NF-κB Activation

2012 ◽  
Vol 80 (11) ◽  
pp. 3939-3951 ◽  
Author(s):  
Hiroyasu Tsutsuki ◽  
Kinnosuke Yahiro ◽  
Kotaro Suzuki ◽  
Akira Suto ◽  
Kohei Ogura ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Escherichia Coli ◽  
Inos Expression ◽  
Inos Mrna ◽  
No Production ◽  
Content Type ◽  
Monocyte Chemoattractant Protein 1 ◽  
E Coli ◽  
Inos Promoter ◽  
Subtilase Cytotoxin

ABSTRACTSubtilase cytotoxin (SubAB), which is produced by certain strains of Shiga-toxigenicEscherichia coli(STEC), cleaves an endoplasmic reticulum (ER) chaperone, BiP/Grp78, leading to induction of ER stress and caspase-dependent apoptosis. SubAB alters the innate immune response. SubAB pretreatment of macrophages inhibited lipopolysaccharide (LPS)-induced production of both monocyte chemoattractant protein 1 (MCP-1) and tumor necrosis factor α (TNF-α). We investigated here the mechanism by which SubAB inhibits nitric oxide (NO) production by mouse macrophages. SubAB suppressed LPS-induced NO production through inhibition of inducible NO synthase (iNOS) mRNA and protein expression. Further, SubAB inhibited LPS-induced IκB-α phosphorylation and nuclear localization of the nuclear factor-κB (NF-κB) p65/p50 heterodimer. Reporter gene and chromatin immunoprecipitation (ChIP) assays revealed that SubAB reduced LPS-induced NF-κB p65/p50 heterodimer binding to an NF-κB binding site on the iNOS promoter. In contrast to the native toxin, a catalytically inactivated SubAB mutant slightly enhanced LPS-induced iNOS expression and binding of NF-κB subunits to the iNOS promoter. The SubAB effect on LPS-induced iNOS expression was significantly reduced in macrophages from NF-κB1 (p50)-deficient mice, which lacked a DNA-binding subunit of the p65/p50 heterodimer, suggesting that p50 was involved in SubAB-mediated inhibition of iNOS expression. Treatment of macrophages with an NOS inhibitor or expression of SubAB byE. coliincreasedE. colisurvival in macrophages, suggesting that NO generated by macrophages resulted in efficient killing of the bacteria and SubAB contributed toE. colisurvival in macrophages. Thus, we hypothesize that SubAB might represent a novel bacterial strategy to circumvent host defense during STEC infection.

scholarly journals Regulation of inducible nitric oxide synthase expression in β cells by environmental factors: heavy metals

1999 ◽  
Vol 338 (3) ◽  
pp. 695-700 ◽  
Author(s):  
Walther ECKHARDT ◽  
Kerstin BELLMANN ◽  
Hubert KOLB
Keyword(s):  
Heavy Metal ◽  
Environmental Factors ◽  
Time Window ◽  
Inos Mrna ◽  
No Production ◽  
Β Cells ◽  
Β Cell ◽  
Cell Functions ◽  
Nitrite Production ◽  
Heavy Metal Salts

The expression of inducible NO synthase (iNOS) in pancreatic islet β cells modulates endocrine cell functions and, at very high levels of NO production causes β-cell death. We tested the hypothesis that environmental factors such as heavy-metal salts modulate iNOS expression in β cells. A rat β-cell line (insulinoma RINm5F) was cultured in the presence of low-dose interleukin (IL)-1β for suboptimal induction of iNOS. PbCl2 (0.1–10 µM) dose-dependently increased NO (measured as nitrite) formation (P< 0.001). In contrast, HgCl2 suppressed nitrite production (0.1–10 µM, P< 0.05). Measurements of iNOS activity by determining citrulline levels confirmed the potentiating effect of PbCl2 (P< 0.05). There was a narrow time window of heavy-metal actions, ranging from -24 h (Hg2+) or -3 h (Pb2+) to +2 h, relative to the addition of IL-1β. By semi-quantitative reverse transcriptase-PCR, enhanced levels of iNOS mRNA were found in the presence of Pb2+ (P< 0.05) and decreased levels in the presence of Hg2+. The amount of iNOS protein as determined by Western blotting was increased in the presence of Pb2+. We conclude that Pb2+ upregulates and Hg2+ suppresses iNOS gene expression at the level of transcription, probably by acting on the signalling pathway. These observations may have important implications for understanding pathological effects of environmental factors on endocrine organ functions.

AVP inhibits LPS- and IL-1β-stimulated NO and cGMP via V1 receptor in cultured rat mesangial cells

1999 ◽  
Vol 276 (3) ◽  
pp. F433-F441 ◽  
Author(s):  
Tetsuo Umino ◽  
Eiji Kusano ◽  
Shigeaki Muto ◽  
Tetsu Akimoto ◽  
Satoru Yanagiba ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Mesangial Cells ◽  
Nuclear Factor Κb ◽  
Inos Mrna ◽  
No Production ◽  
Dependent Manner ◽  
Glomerular Mesangial Cells ◽  
Inos Protein ◽  
Nitrite Production ◽  
Inhibitor Of Protein Synthesis

The present study examined how arginine vasopressin (AVP) affects nitric oxide (NO) metabolism in cultured rat glomerular mesangial cells (GMC). GMC were incubated with test agents and nitrite, and intracellular cGMP content, inducible nitric oxide synthase (iNOS) mRNA, and iNOS protein were analyzed by the Griess method, enzyme immunoassay, and Northern and Western blotting, respectively. AVP inhibited lipopolysaccharide (LPS)- and interleukin-1β (IL-1β)-induced nitrite production in a dose- and time-dependent manner, with concomitant changes in cGMP content, iNOS mRNA, and iNOS protein. This inhibition by AVP was reversed by V1- but not by oxytocin-receptor antagonist. Inhibition by AVP was also reproduced on LPS and interferon-γ (IFN-γ). Protein kinase C (PKC) inhibitors reversed AVP inhibition, whereas PKC activator inhibited nitrite production. Although dexamethasone and pyrrolidinedithiocarbamate (PDTC), inhibitors of nuclear factor-κB, inhibited nitrite production, further inhibition by AVP was not observed. AVP did not show further inhibition of nitrite production with actinomycin D, an inhibitor of transcription, or cycloheximide, an inhibitor of protein synthesis. In conclusion, AVP inhibits LPS- and IL-1β-induced NO production through a V1 receptor. The inhibitory action of AVP involves both the activation of PKC and the transcription of iNOS mRNA in cultured rat GMC.

scholarly journals Cytokine and Nitric Oxide-Dependent Gene Regulation in Islet Endocrine and Nonendocrine Cells

Function ◽  
2021 ◽  
Author(s):  
Jennifer S Stancill ◽  
Moujtaba Y Kasmani ◽  
Achia Khatun ◽  
Weiguo Cui ◽  
John A Corbett
Keyword(s):  
Nitric Oxide ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Endocrine Cells ◽  
Physiological Role ◽  
Cytokine Signaling ◽  
Inos Mrna ◽  
Β Cells ◽  
Β Cell ◽  
Shock Proteins

Abstract While exposure to inflammatory cytokines is thought to contribute to pancreatic β-cell damage during diabetes, primarily because cytokine-induced nitric oxide impairs β-cell function and causes cell death with prolonged exposure, we hypothesize that there is a physiological role for cytokine signaling that functions to protect β-cells from a number of environmental stresses. This hypothesis is derived from the knowledge that β-cells are essential for survival even though they have a limited capacity to replicate, yet they are exposed to high cytokine levels during infection as most of the pancreatic blood flow is directed to islets. Here, mouse islets were subjected to single-cell RNA sequencing following 18-hr cytokine exposure. Treatment with IL-1β and IFN-γ leads to expression of inducible nitric oxide synthase (iNOS) mRNA and antiviral and immune-associated genes as well as repression of islet identity factors in a subset of β- and non-β endocrine cells in a nitric oxide-independent manner. Nitric oxide-dependent expression of genes encoding heat shock proteins was observed in both β- and non-β endocrine cells. Interestingly, cells with high expression of heat shock proteins failed to increase antiviral and immune-associated genes, suggesting that nitric oxide may be an internal “off switch” to prevent the negative effects of prolonged cytokine signaling in islet endocrine cells. We found no evidence for pro-apoptotic gene expression following 18-hr cytokine exposure. Our findings suggest that the primary functions of cytokines and nitric oxide are to protect islet endocrine cells from damage, and only when regulation of cytokine signaling is lost does irreversible damage occur.

scholarly journals Influence of hCG on inducible nitric oxide synthase gene expression in ram testicular arteries

2014 ◽  
Vol 86 (3) ◽  
pp. 183
Author(s):  
Maria Matteo ◽  
Annalisa Rizzo ◽  
Ettore Cicinelli ◽  
Elvira Grandone ◽  
Giuseppe Cardo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Inos Expression ◽  
P Value ◽  
Inos Mrna ◽  
Inos Gene ◽  
Before And After ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide ◽  
Nos Gene

Background. Experimental evidence suggests a relationship between the vasodilatory effect of hCG and the NOS system in the testis. The influence of hCG administration on testicular vascular NOS gene expression has not been fully investigated. Objective: This study aimed to evaluate the presence of the nitric oxide syntheses gene in ram testicular arteries and the influence of hCG administration on its expression. Materials and methods: Both testicular arteries of sixteen rams were extracted before and after i.v. administration of 5000 IU of hCG or placebo. The expression of the iNOS gene was investigated by real time PCR. Data were analyzed by means of Wilcoxon and Mann-Whitney tests. A p value of &lt; 0.05 was considered statistically significant. Results: PCR revealed the presence of iNOS mRNA in all basal samples but the expression of the iNOS gene was significantly reduced in all arteries obtained 24 h after the administration of either hCG or placebo. A significant reduction in the expression of iNOS gene was observed in the testicular arteries extracted after 24 h in both treated and placebo groups. On the other hand hCG stimulation did not significantly influence iNOS expression following its administration compared to a placebo. Conclusion: Ram testicular arteries express the iNOS gene but hCG stimulation did not significantly influence iNOS expression. A significant reduction in the expression of this gene was observed in the testicular arteries extracted after 24 h in both treated and placebo groups, suggesting that iNOS expression on the testicular artery could be influenced by the spermatic vessel ligation of the controlateral testis.

Intratracheal adenoviral-mediated delivery of iNOS decreases pulmonary vasoconstrictor responses in rats

2004 ◽  
Vol 97 (5) ◽  
pp. 1814-1822 ◽  
Author(s):  
Louis G. Chicoine ◽  
Edith Tzeng ◽  
Rebekah Bryan ◽  
Steven Saenz ◽  
Michael L. Paffett ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Exhaled Nitric Oxide ◽  
Time Dependent ◽  
Inos Mrna ◽  
Alveolar Wall ◽  
Gene Transduction ◽  
Inos Protein ◽  
Protein Levels ◽  
Inos Gene ◽  
Adenoviral Construct

We hypothesized that adenovirus-mediated inducible nitric oxide synthase (iNOS) gene transduction of the lung would result in time-dependent iNOS overexpression and attenuate the vascular constrictor responses to a thromboxane mimetic, U-46619. Rats were treated via the trachea with surfactant alone (sham), surfactant containing an adenoviral construct with a cytomegalovirus promoter-regulated human iNOS gene (Adeno-iNOS), or an adenoviral construct without a gene insert (Adeno-Control). Adeno-iNOS-transduced rats demonstrated human iNOS mRNA and increased iNOS protein levels only in the lungs. Immunohistochemistry of lungs from Adeno-iNOS-treated animals demonstrated transgene expression in alveolar wall cells. In the lungs from Adeno-iNOS-transduced rats, the expression of iNOS protein and exhaled nitric oxide concentrations were increased on days 1–4 and 7 but returned to baseline values by day 14. The administration of the selective iNOS inhibitor l- N6-(1-iminoethyl)lysine dihydrochloride (l-NIL) decreased exhaled nitric oxide concentrations to levels found in Adeno-Control-transduced lungs. In a second group of rats, the segmental vasoconstrictor responses to U-46619 were determined in isolated, perfused lungs 3 days after transduction. Lungs from rats transduced with Adeno-iNOS had reduced total, arterial, and venous vasoconstrictor responses to U-46619 compared with sham, Adeno-Control, and control groups. In a third set of experiments, the response to 400 nM U-46619 in the presence of 10 μM l-NIL was not different in the isolated lungs from Adeno-Control- and Adeno-iNOS-transduced rats. We conclude that adenovirus-mediated iNOS gene transduction of the lung results in time-dependent iNOS overexpression, which attenuates the vascular constrictor responses to the thromboxane mimetic U-46619.

PPARγ is not required for the inhibitory actions of PGJ2 on cytokine signaling in pancreatic β-cells

2004 ◽  
Vol 286 (3) ◽  
pp. E329-E336 ◽  
Author(s):  
Sarah M. Weber ◽  
Anna L. Scarim ◽  
John A. Corbett
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Cytokine Signaling ◽  
Rinm5f Cells ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Inos Gene ◽  
Ifn Γ ◽  
Anti Inflammatory ◽  
Inos Gene Expression

Peroxisome proliferator-activated receptor (PPAR)γ agonists, such as 15-deoxy-Δ12,14-prostaglandin J2 (PGJ2) and troglitazone, have been shown to elicit anti-inflammatory effects in pancreatic β-cells that include inhibition of cytokine-stimulated inducible nitric oxide synthase (iNOS) gene expression and production of nitric oxide. In addition, these ligands impair IL-1-induced NF-κB and MAPK as well as IFN-γ-stimulated signal transducer and activator of transcription (STAT)1 activation in β-cells. The purpose of this study was to determine if PPARγ activation participates in the anti-inflammatory actions of PGJ2 in β-cells. Pretreatment of RINm5F cells for 6 h with PGJ2 results in inhibition of IL-1-stimulated IκB degradation and IFN-γ-stimulated STAT1 phosphorylation. Overexpression of a dominant-negative (dn) PPARγ mutant or treatment with the PPARγ antagonist GW-9662 does not modulate the inhibitory actions of PGJ2 on cytokine signaling in RINm5F cells. Although these agents fail to attenuate the inhibitory actions of PGJ2 on cytokine signaling, they do inhibit PGJ2-stimulated PPARγ response element reporter activity. Consistent with the inability to attenuate the inhibitory actions of PGJ2 on cytokine signaling, neither dnPPARγ nor GW-9662 prevents the inhibitory actions of PGJ2 on IL-1-stimulated iNOS gene expression or nitric oxide production by RINm5F cells. These findings support a PPARγ-independent mechanism by which PPARγ ligands impair cytokine signaling and iNOS expression by islets.

scholarly journals INTERLEUKIN-1β INDUCES NITRIC OXIDE SYNTHASE BY HAMSTER PANCREAS β CELL LINE (HIT-T15)

1993 ◽  
Vol 14 (2) ◽  
pp. 117-122 ◽  
Author(s):  
KAZUKI OHTA ◽  
YUKIO HIRATA ◽  
TAIHEI IMAI ◽  
FUMIAKI MARUMO
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Cell Line ◽  
Interleukin 1Β ◽  
Β Cell ◽  
Oxide Synthase
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