scholarly journals Carbon monoxide differentially inhibits TLR signaling pathways by regulating ROS-induced trafficking of TLRs to lipid rafts

2006 ◽  
Vol 203 (10) ◽  
pp. 2377-2389 ◽  
Author(s):  
Kiichi Nakahira ◽  
Hong Pyo Kim ◽  
Xue Hui Geng ◽  
Atsunori Nakao ◽  
Xue Wang ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Nadph Oxidase ◽  
Signaling Pathways ◽  
Lipid Rafts ◽  
Poly I:C ◽  
Early Event ◽  
Ros Production ◽  
Tlr Signaling ◽  
Polycytidylic Acid ◽  
Diphenylene Iodonium

Carbon monoxide (CO), a byproduct of heme catabolism by heme oxygenase (HO), confers potent antiinflammatory effects. Here we demonstrate that CO derived from HO-1 inhibited Toll-like receptor (TLR) 2, 4, 5, and 9 signaling, but not TLR3-dependent signaling, in macrophages. Ligand-mediated receptor trafficking to lipid rafts represents an early event in signal initiation of immune cells. Trafficking of TLR4 to lipid rafts in response to LPS was reactive oxygen species (ROS) dependent because it was inhibited by diphenylene iodonium, an inhibitor of NADPH oxidase, and in gp91phox-deficient macrophages. CO selectively inhibited ligand-induced recruitment of TLR4 to lipid rafts, which was also associated with the inhibition of ligand-induced ROS production in macrophages. TLR3 did not translocate to lipid rafts by polyinosine-polycytidylic acid (poly(I:C)). CO had no effect on poly(I:C)-induced ROS production and TLR3 signaling. The inhibitory effect of CO on TLR-induced cytokine production was abolished in gp91phox-deficient macrophages, also indicating a role for NADPH oxidase. CO attenuated LPS-induced NADPH oxidase activity in vitro, potentially by binding to gp91phox. Thus, CO negatively controlled TLR signaling pathways by inhibiting translocation of TLR to lipid rafts through suppression of NADPH oxidase–dependent ROS generation.

scholarly journals Carbon monoxide differentially inhibits TLR signaling pathways by regulating ROS-induced trafficking of TLRs to lipid rafts

2006 ◽  
Vol 175 (1) ◽  
pp. i2-i2
Author(s):  
Kiichi Nakahira ◽  
Hong Pyo Kim ◽  
Xue Hui Geng ◽  
Atsunori Nakao ◽  
Xue Wang ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Signaling Pathways ◽  
Lipid Rafts ◽  
Tlr Signaling

Volume-sensitive NADPH oxidase activity and taurine efflux in NIH3T3 mouse fibroblasts

2008 ◽  
Vol 294 (6) ◽  
pp. C1552-C1565 ◽  
Author(s):  
Martin Barfred Friis ◽  
Katrine Gribel Vorum ◽  
Ian Henry Lambert
Keyword(s):  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Ros Production ◽  
Taurine Release ◽  
Nitric Oxide Synthase Inhibitor ◽  
Nih3t3 Cells ◽  
Hypotonic Stress ◽  
Diphenylene Iodonium ◽  
Synthase Inhibitor ◽  
Si Rna

Reactive oxygen species (ROS) are produced in NIH3T3 fibroblasts during hypotonic stress, and H2O2 potentiates the concomitant release of the organic osmolyte taurine (Lambert IH. J Membr Biol 192: 19–32, 2003). The increase in ROS production [5-(and-6)-carboxy-2′, 7′-dichlorodihydrofluorescein diacetate fluorescence] is detectable after a reduction in the extracellular osmolarity from 335 mosM (isotonic) to 300 mosM and reaches a maximal value after a reduction to 260 mosM. The swelling-induced ROS production is reduced by the flavoprotein inhibitor diphenylene iodonium chloride (25 μM) but is unaffected by the nitric oxide synthase inhibitor Nω-nitro-l-arginine methyl ester, indicating that the volume-sensitive ROS production is NADPH oxidase dependent. NIH3T3 cells express the NADPH oxidase components: p22phox, a NOX4 isotype; p47phox; and p67phox (real-time PCR). Exposure to the Ca2+-mobilizing agonist ATP (10 μM) potentiates the release of taurine but has no effect on ROS production under hypotonic conditions. On the other hand, addition of the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA, 100 nM) or the lipid messenger lysophosphatidic acid (LPA, 10 nM) potentiates the swelling-induced taurine release as well as the ROS production. Overexpression of Rac1 or p47phox or p47phox knockdown [small interfering (si)RNA] had no effect on the swelling-induced ROS production or taurine release. NOX4 knockdown (siRNA) impairs the increase in the ROS production and the concomitant taurine release following osmotic exposure. It is suggested that a NOX4 isotype plus p22phox account for the swelling-induced increase in the ROS production in NIH3T3 cells and that the oxidase activity is potentiated by PKC and LPA but not by Ca2+.

scholarly journals β-Aminobutyric Acid Primes an NADPH Oxidase–Dependent Reactive Oxygen Species Production During Grapevine-Triggered Immunity

2010 ◽  
Vol 23 (8) ◽  
pp. 1012-1021 ◽  
Author(s):  
Carole Dubreuil-Maurizi ◽  
Sophie Trouvelot ◽  
Patrick Frettinger ◽  
Alain Pugin ◽  
David Wendehenne ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Nadph Oxidase ◽  
Molecular Mechanisms ◽  
Reactive Oxygen ◽  
Aminobutyric Acid ◽  
Ros Production ◽  
Oxygen Species ◽  
Defense Gene Expression ◽  
Diphenylene Iodonium ◽  
Signaling Events

The molecular mechanisms underlying the process of priming are poorly understood. In the present study, we investigated the early signaling events triggered by β-aminobutyric acid (BABA), a well-known priming-mediated plant resistance inducer. Our results indicate that, in contrast to oligogalacturonides (OG), BABA does not elicit typical defense-related early signaling events nor defense-gene expression in grapevine. However, in OG-elicited cells pretreated with BABA, production of reactive oxygen species (ROS) and expression of the respiratory-burst oxidase homolog RbohD gene were primed. In response to the causal agent of downy mildew Plasmopara viticola, a stronger ROS production was specifically observed in BABA-treated leaves. This process was correlated with an increased resistance. The NADPH oxidase inhibitor diphenylene iodonium (DPI) abolished this primed ROS production and reduced the BABA-induced resistance (BABA-IR). These results suggest that priming of an NADPH oxidase–dependent ROS production contributes to BABA-IR in the Vitis-Plasmopara pathosystem.

scholarly journals TLR3 activation increases chemokine expression in human fetal airway smooth muscle cells

2016 ◽  
Vol 310 (2) ◽  
pp. L202-L211 ◽  
Author(s):  
Arij Faksh ◽  
Rodney D. Britt ◽  
Elizabeth R. Vogel ◽  
Michael A. Thompson ◽  
Hitesh C. Pandya ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Respiratory Syncytial Virus ◽  
Signaling Pathways ◽  
Airway Smooth Muscle ◽  
Poly I:C ◽  
Airway Smooth Muscle Cells ◽  
Tlr Agonists ◽  
Polycytidylic Acid ◽  
Syncytial Virus

Viral infections, such as respiratory syncytial virus and rhinovirus, adversely affect neonatal and pediatric populations, resulting in significant lung morbidity, including acute asthma exacerbation. Studies in adults have demonstrated that human airway smooth muscle (ASM) cells modulate inflammation through their ability to secrete inflammatory cytokines and chemokines. The role of ASM in the developing airway during infection remains undefined. In our study, we used human fetal ASM cells as an in vitro model to examine the effect of Toll-like receptor (TLR) agonists on chemokine secretion. We found that fetal ASM express multiple TLRs, including TLR3 and TLR4, which are implicated in the pathogenesis of respiratory syncytial virus and rhinovirus infection. Cells were treated with TLR agonists, polyinosinic-polycytidylic acid [poly(I:C)] (TLR3 agonist), lipopolysaccharide (TLR4 agonist), or R848 (TLR7/8 agonist), and IL-8 and chemokine (C-C motif) ligand 5 (CCL5) secretion were evaluated. Interestingly, poly(I:C), but neither lipopolysaccharide nor R848, increased IL-8 and chemokine (C-C motif) ligand 5 secretion. Examination of signaling pathways suggested that the poly(I:C) effects in fetal ASM involve TLR and ERK signaling, in addition to another major inflammatory pathway, NF-κB. Moreover, there are variations between fetal and adult ASM with respect to poly(I:C) effects on signaling pathways. Pharmacological inhibition suggested that ERK pathways mediate poly(I:C) effects. Overall, our data show that poly(I:C) initiates activation of proinflammatory pathways in developing ASM, which may contribute to immune responses to infection and exacerbation of asthma.

NADPH oxidase plays a crucial role in the activation of pancreatic stellate cells

2008 ◽  
Vol 294 (1) ◽  
pp. G99-G108 ◽  
Author(s):  
Atsushi Masamune ◽  
Takashi Watanabe ◽  
Kazuhiro Kikuta ◽  
Kennichi Satoh ◽  
Tooru Shimosegawa
Keyword(s):  
Chronic Pancreatitis ◽  
Nadph Oxidase ◽  
Stellate Cells ◽  
Pancreatic Fibrosis ◽  
Pancreatic Stellate Cells ◽  
Human Pancreas ◽  
Ros Production ◽  
Chemokine Production ◽  
Cell Functions ◽  
Diphenylene Iodonium

Activated pancreatic stellate cells (PSCs) play an important role in pancreatic fibrosis and inflammation, where oxidative stress is implicated in the pathogenesis. NADPH oxidase might be a source of reactive oxygen species (ROS) in the injured pancreas. This study aimed to clarify the expression and regulation of cell functions by NADPH oxidase in PSCs. PSCs were isolated from rat and human pancreas tissues. Expression of NADPH oxidase was assessed by reverse transcription-PCR and immunostaining. Intracellular ROS production was assessed using 2′,7′-dichlorofluorescin diacetate. The effects of diphenylene iodonium (DPI) and apocynin, inhibitors of NADPH oxidase, on key parameters of PSC activation were evaluated in vitro. In vivo, DPI (at 1 mg·kg body wt−1·day−1) was administered in drinking water to 10-wk-old male Wistar Bonn/Kobori rats for 10 wk and to rats with chronic pancreatitis induced by dibutyltin dichloride (DBTC). PSCs expressed key components of NADPH oxidase (p22phox, p47phox, NOX1, gp91phox/NOX2, NOX4, and NOX activator 1). PDGF-BB, IL-1β, and angiotensin II induced ROS production, which was abolished by DPI and apocynin. DPI inhibited PDGF-induced proliferation, IL-1β-induced chemokine production, and expression of α-smooth muscle actin and collagen. DPI inhibited transformation of freshly isolated cells to a myofibroblast-like phenotype. In addition, DPI inhibited the development of pancreatic fibrosis in Wistar Bonn/Kobori rats and in rats with DBTC-induced chronic pancreatitis. In conclusion, PSCs express NADPH oxidase to generate ROS, which mediates key cell functions and activation of PSCs. NADPH oxidase might be a potential target for the treatment of pancreatic fibrosis.

scholarly journals Neutrophil NET Formation with Microbial Stimuli Requires Late Stage NADPH Oxidase Activity

Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1791
Author(s):  
Heather A. Parker ◽  
Harry M. Jones ◽  
Christopher D. Kaldor ◽  
Mark B. Hampton ◽  
Christine C. Winterbourn
Keyword(s):  
Nadph Oxidase ◽  
Late Stage ◽  
Significant Inhibition ◽  
Early Event ◽  
Cytoplasmic Proteins ◽  
Total Inhibition ◽  
Diphenylene Iodonium ◽  
Oxidant Production ◽  
Histone Citrullination ◽  
Net Release

Neutrophils respond to a range of stimuli by releasing extracellular traps (NETs), a mesh consisting of chromatin plus granule and cytoplasmic proteins. We have investigated NET release in response to phorbol myristate acetate (PMA), Pseudomonas aeruginosa (PAO1), Staphylococcus aureus and Candida albicans, and the involvement of NADPH oxidase (NOX2) and myeloperoxidase (MPO) activities. An oxidative mechanism was involved with each stimulus, and the NOX2 inhibitor diphenylene iodonium (DPI) gave almost total inhibition. Notably, DPI added up to 60–90 min after stimulation still gave significant inhibition of subsequent NET formation. As most of the NOX2 activity had already occurred by that time, this indicates a requirement for late-stage low-level oxidant production. Inhibition of histone citrullination did not suppress NET formation, indicating that this was not the essential oxidant-dependent step. With PMA and P. aeruginosa PAO1, MPO activity played an important role in the induction of NETs and MPO inhibitors added up to 30–90 min after stimulation suppressed NET formation. NET formation with S. aureus and C. albicans was insensitive to MPO inhibition. Thus, MPO products are important with some stimuli but not others. Our results extend earlier observations with PMA and show that induction of NETs by microbial stimuli requires late stage oxidant production. Others have shown that NET formation involves NOX2-dependent elastase release from granules. As this is an early event, we conclude from our results that there is more than one oxidant-dependent step.

scholarly journals PSX-41 Effect of Polyinosinic-polycytidylic acid on gene expression in goat blood

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 449-449
Author(s):  
Kingsley Ekwemalor ◽  
Mulumebet Worku
Keyword(s):  
Gene Expression ◽  
Signaling Pathway ◽  
Group Treatment ◽  
Fold Change ◽  
Poly I:C ◽  
Control Group ◽  
Tlr Signaling ◽  
Polycytidylic Acid ◽  
Tlr Signaling Pathway ◽  
Polyinosinic Polycytidylic Acid

Abstract The objective of this study was to investigate the effect of Polyinosinic-polycytidylic [poly(I:C)] acid on gene activation in goat blood. Polyinosinic-polycytidylic acid is a synthetic dsRNA analogue that binds to Toll-like receptor (TLR) 3. Synthetic TLR agonists are promising immune modulators. Blood samples were collected from the jugular vein of BoerXSpanish goats (n = 3) into tubes containing an anticoagulant. Whole blood was treated with the 12.5 µg/ml of poly I:C or 200µl of PBS which served as control. Cells were incubated at 37°C with 5% CO2 and 85% humidity for 30 minutes. Total RNA was isolated from the pellet using Trizol and then converted to cDNA using RETROscript kit (Qiagen). The expression of 84 genes in the human TLR signaling pathway RT2 PCR Array was evaluated using real-time PCR. Fold change in gene expression was calculated using the 2−ΔΔCt method. The housekeeping gene GAPDH, ACTB, HPRT1, TBP, and YWHAZ was used to normalize the data. Fold change was set at a cutoff of 2. Following treatment with poly I:C, 24 genes were up-regulated, 15 genes were down-regulated. The gene MAPK8 was induced by poly I:C treatment. Only 74 genes were expressed in the control. Thirty-nine genes were expressed in both the control group and poly I:C treatment group. Treatment with poly I:C also down-regulated some of the genes tested. Our results show that treatment poly I:C modulated the expression of genes in the TLR signaling pathway and provides insights into how goats respond to viral pathogens for the design of adjuvants to enhance the immune response.

Eff ects of hyperbaric oxygen on NLRP3 infl ammasome activation in the brain aft er carbon monoxide poisoning

2020 ◽  
pp. 607-619
Author(s):  
Ya’nan Qi ◽  
◽  
Zhibao Guo ◽  
Huijun Hu ◽  
Xiang’en Meng ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Nadph Oxidase ◽  
Hyperbaric Oxygen ◽  
Nlrp3 Inflammasome ◽  
Carbon Monoxide Poisoning ◽  
Enzyme Linked Immunosorbent Assay ◽  
Inflammasome Activation ◽  
Protein Levels ◽  
Nlrp3 Inflammasome Activation ◽  
Myelin Injury

Neuroinflammation plays an important role in brain damage after acute carbon monoxide poisoning (ACOP). The nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing (NLRP) 3 inflammasome triggers the activation of inflammatory caspases and maturation of interleukin (IL)-1β and -18, and has been linked to various human autoinflammatory and autoimmune diseases. In this study we investigated the effects of hyperbaric oxygen (HBO2) on NLRP3 inflammasome activation after ACOP. Mice were randomly divided into four groups: sham group (exposure to normobaric air – i.e., 21% O2 at 1 atmosphere absolute); HBO2-only group; CO + normobaric air group; and CO + HBO2 group. Cognitive function was evaluated with the Morris water maze; myelin injury was assessed by Fluoro-Myelin GreenTM fluorescent myelin staining and myelin basic protein (MBP) immunostaining; and mRNA and protein levels of NLRP3 inflammasome complex proteins were measured by quantitative real-time PCR and Western blot, respectively. Additionally, serum and brain levels of IL-1β and -18 and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase were determined by enzyme-linked immunosorbent assay. It was found that HBO2 improved learning and memory, and alleviated myelin injury in mice subjected to acute CO exposure. Furthermore, HBO2 decreased NLRP3, absent in melanoma 2 (AIM2), caspase-1, and apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain mRNA and protein levels, and reduced brain and serum concentrations of IL-1β and -18 and NADPH oxidase. These results indicate that HBO2 suppresses the inflammatory response after ACOP by blocking NLRP3 inflammasome activation, thereby alleviating cognitive deficits.

scholarly journals NF-κB, JNK, and TLR Signaling Pathways in Hepatocarcinogenesis

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Shin Maeda
Keyword(s):  
Hepatocellular Carcinoma ◽  
Signaling Pathways ◽  
Inflammatory Cell ◽  
Prognostic Markers ◽  
Tumor Promotion ◽  
Neoplastic Cell ◽  
Nuclear Factor ◽  
Tlr Signaling ◽  
The Third

Hepatocellular carcinoma (HCC) is the third largest cause of cancer deaths worldwide. The role of molecular changes in HCC have been used to identify prognostic markers and chemopreventive or therapeutic targets. It seems that toll-like receptors (TLRs) as well as the nuclear factor (NF)-κB, and JNK pathways are critical regulators for the production of the cytokines associated with tumor promotion. The cross-talk between an inflammatory cell and a neoplastic cell, which is instigated by the activation of NF-κB and JNKs, is critical for tumor organization. JNKs also regulate cell proliferation and act as oncogenes, making them the main tumor-promoting protein kinases. TLRs play roles in cytokine and hepatomitogen expression mainly in myeloid cells and may promote liver tumorigenesis. A better understanding of these signaling pathways in the liver will help us understand the mechanism of hepatocarcinogenesis and provide a new therapeutic target for HCC.

Cigarette smoke extract amplifies NADPH oxidase-dependent ROS production to inactivate PTEN by oxidation in BEAS-2B cells

2021 ◽  
Vol 150 ◽  
pp. 112050
Author(s):  
Bangrong Cai ◽  
Mengya Liu ◽  
Jinxing Li ◽  
Dujuan Xu ◽  
Jiansheng Li
Keyword(s):  
Nadph Oxidase ◽  
Cigarette Smoke ◽  
Cigarette Smoke Extract ◽  
Ros Production
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