Hydrogen peroxide downregulates IL-1-driven mesangial iNOS activity: implications for glomerulonephritis

1997 ◽  
Vol 272 (6) ◽  
pp. F721-F728 ◽  
Author(s):  
E. A. Jaimes ◽  
K. A. Nath ◽  
L. Raij

In glomerulonephritides, autacoids such as nitric oxide (NO), reactive oxygen species, and prostanoids are produced in increased amounts in response to cytokines such as interleukin-1 (IL-1). These autacoids influence the expression of glomerular injury by their direct as well as interactive actions. We studied the effect of hydrogen peroxide (H2O2) on NO production in rat mesangial cells. We demonstrate that transient exposure of mesangial cells to H2O2 prior to sustained exposure to IL-1 decreased extracellular accumulation of NO2/NO3 and cellular guanosine 3,'5'-cyclic monophosphate (cGMP) content. H2O2 markedly impaired inducible nitric oxide synthase (iNOS) activity induced by IL-1 directly measured by the conversion of L-[14C]arginine to L-[14C]citrulline. Such impairment in iNOS activity was accompanied by a parallel reduction in iNOS protein abundance but not by a reduced expression of iNOS mRNA. The inhibitory effect of H2O2 on NOS activity was further supported by peroxide-induced impairment in IL-1-driven, NO-dependent synthesis of prostaglandin E2. Our studies thus provide the first direct evidence of a posttranscriptional inhibitory effect of H2O2 on iNOS activity. Additionally, our studies uncover the existence of a previously unrecognized effect of H2O2 on the production of NO that may exert influence on the severity of glomerular injury during glomerular inflammation.

1996 ◽  
Vol 313 (2) ◽  
pp. 641-646 ◽  
Author(s):  
Marta SAURA ◽  
Rosa MARTÍNEZ-DALMAU ◽  
Adrian MINTY ◽  
Dolores PÉREZ-SALA ◽  
Santiago LAMAS

The synthesis of nitric oxide in inflammatory situations requires the expression of an inducible isoform of nitric oxide synthase (iNOS). Human mesangial cells (HMC) express an iNOS enzyme after exposure to multiple co-stimuli. In this study we have observed that while tumour necrosis factor-α, interleukin (IL)-1β, interferon-γ and bacterial lipopolysaccharide (LPS) were unable to significantly induce NO synthesis when used alone, they induced an evident stimulation of NO synthesis when used in various combinations. A mixture of the three cytokines (CM) and LPS resulted in a 10-15-fold stimulation of NO synthesis over control values which started to be significant after 16 h. The addition of IL-13, a cytokine with anti-inflammatory properties, inhibited CM/LPS-induced NO synthesis in a concentration-dependent manner. A marked inhibitory effect (60-65%) could be observed when HMC were treated with IL-13 (10 ng/ml) 24 h before, at the same time as, or even 4 h after the addition of CM/LPS. This inhibitory effect was still significant (25%) when IL-13 was added 16 h after CM/LPS. Northern analysis showed that IL-13-mediated iNOS inhibition was closely correlated with the suppression of iNOS mRNA expression. These results identify IL-13 as a powerful regulatory tool for the inhibition of NO synthesis in human cells, a property which may be pathophysiologically relevant in NO-related inflammatory processes.


2009 ◽  
Vol 297 (3) ◽  
pp. C742-C749 ◽  
Author(s):  
Jianhai Du ◽  
Na Wei ◽  
Tongju Guan ◽  
Hao Xu ◽  
Jianzhong An ◽  
...  

In inflammatory diseases, tissue damage is critically associated with nitric oxide (·NO) and cytokines, which are overproduced in response to cellular release of endotoxins. Here we investigated the inhibitory effect of roscovitine, a selective inhibitor of cyclin-dependent kinases (CDKs) on ·NO production in mouse macrophages. In RAW264.7 cells, we found that roscovitine abolished the production of ·NO induced by lipopolysaccharide (LPS). Moreover, roscovitine significantly inhibited LPS-induced inducible nitric oxide synthase (iNOS) mRNA and protein expression. Our data also showed that roscovitine attenuated LPS-induced phosphorylation of IκB kinase β (IKKβ), IκB, and p65 but enhanced the phosphorylation of ERK, p38, and c-Jun NH2-terminal kinase (JNK). In addition, roscovitine dose dependently inhibited LPS-induced expression of cyclooxygenase-2 (COX)-2, IL-1β, and IL-6 but not tumor necrosis factor (TNF)-α. Tetrahydrobiopterin (BH4), an essential cofactor for iNOS, is easily oxidized to 7,8-dihydrobiopterin (BH2). Roscovitine significantly inhibited LPS-induced BH4 biosynthesis and decreased BH4-to-BH2 ratio. Furthermore, roscovitine greatly reduced the upregulation of GTP cyclohydrolase-1 (GCH-1), the rate-limiting enzyme for BH4 biosynthesis. Using other CDK inhibitors, we found that CDK1, CDK5, and CDK7, but not CDK2, significantly inhibited LPS-induced ·NO production in macrophages. Similarly, in isolated peritoneal macrophages, roscovitine strongly inhibited ·NO production, iNOS, and COX-2 upregulation, activation of NFκB, and induction of GCH-1 by LPS. Together, our data indicate that roscovitine abolishes LPS-induced ·NO production in macrophages by suppressing nuclear factor-κB activation and BH4 biosynthesis, which might be mediated by CDK1, CDK5, and CDK7. Our results also suggest that roscovitine may inhibit inflammation and that CDKs may play important roles in the mechanisms by which roscovitine attenuates inflammation.


1995 ◽  
Vol 269 (1) ◽  
pp. C55-C59 ◽  
Author(s):  
T. Tetsuka ◽  
A. R. Morrison

The inflammatory cytokine interleukin-1 (IL-1) induces the inducible form of nitric oxide synthase (iNOS) with an increase in nitric oxide in rat mesangial cells. However, the cellular mechanisms that underlie the induction of iNOS by IL-1 beta in mesangial cells has not been clarified. Because we have shown that tyrosine kinase inhibitors attenuate IL-1 beta-induced cyclooxygenase expression and prostaglandin production, we investigated the effect of tyrosine kinase inhibitors on IL-1 beta-induced nitrite production and iNOS mRNA expression in rat mesangial cells. The tyrosine kinase inhibitors genistein and herbimycin A attenuated IL-1 beta-induced nitrite production in a dose-dependent manner. In addition, both of these inhibitors blocked IL-1 beta-induced iNOS mRNA expression. These data suggest that tyrosine kinase(s) plays a central role in IL-1 beta signaling to induce iNOS in rat mesangial cells.


2018 ◽  
Vol 60 (No. 8) ◽  
pp. 359-366
Author(s):  
J. Li ◽  
B. Shi ◽  
S. Yan ◽  
L. Jin ◽  
Y. Guo ◽  
...  

The effects of chitosan on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) activity and gene expression in vivo or vitro were investigated in weaned piglets. In vivo, 180 weaned piglets were assigned to five dietary treatments with six replicates. The piglets were fed on a basal diet supplemented with 0 (control), 100, 500, 1000, and 2000 mg chitosan/kg feed, respectively. In vitro, the peripheral blood mononuclear cells (PBMCs) from a weaned piglet were cultured respectively with 0 (control), 40, 80, 160, and 320 µg chitosan/ml medium. Results showed that serum NO concentrations on days 14 and 28 and iNOS activity on day 28 were quadratically improved with increasing chitosan dose (P < 0.05). The iNOS mRNA expressions were linearly or quadratically enhanced in the duodenum on day 28, and were improved quadratically in the jejunum on days 14 and 28 and in the ileum on day 28 (P < 0.01). In vitro, the NO concentrations, iNOS activity, and mRNA expression in unstimulated PBMCs were quadratically enhanced by chitosan, but the improvement of NO concentrations and iNOS activity by chitosan were markedly inhibited by N-(3-[aminomethyl] benzyl) acetamidine (1400w) (P < 0.05). Moreover, the increase of NO concentrations, iNOS activity, and mRNA expression in PBMCs induced by lipopolysaccharide (LPS) were suppressed significantly by chitosan (P < 0.05). The results indicated that the NO concentrations, iNOS activity, and mRNA expression in piglets were increased by feeding chitosan in a dose-dependent manner. In addition, chitosan improved the NO production in unstimulated PBMCs but inhibited its production in LPS-induced cells, which exerted bidirectional regulatory effects on the NO production via modulated iNOS activity and mRNA expression.


Nutrients ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 984 ◽  
Author(s):  
Selom Avotri ◽  
Danita Eatman ◽  
Karen Russell-Randall

Purpose: Resveratrol (RSV), an antioxidant polyphenol, has demonstrated beneficial effects in various ocular diseases including glaucoma. Our study was designed to evaluate the effects of RSV on nitric oxide synthase (NOS) enzymes, nitric oxide (NO) and interleukin-1 alpha (IL-1 α), in human glaucomatous trabecular meshwork (TM) cells. Methods: Western blot was utilized to determine endothelial and inducible NOS (eNOS, iNOS) expression. The concentration-related effects of RSV on IL-1 α and NO levels were assessed using the respective ELISA kits. Results: Densitometry data showed concentration-related increases in eNOS, and reduction in iNOS expression at high RSV concentrations. RSV treatment (0.1, 1, 10 and 100 µM) resulted in increased NO levels (6 ± 0.7, 7 ± 0.8, 7.3 ± 0.7 and 9.5 ± 1 nM/mg protein, respectively). The average value obtained for control was 4.8 ± 0.6 nM/mg protein. Significant increases in IL-1α levels were observed with lower concentrations of RSV. However, at higher RSV concentrations (10–100 μM), IL-1 levels decreased. Conclusions: Resveratrol increased NO in glaucomatous TM cells, possibly by increasing eNOS expression. Thus, RSV-induced NO production supports the beneficial effects of this antioxidant in glaucoma. Furthermore, our results showing a reduction in iNOS, a contributor to oxidative stress expression, further support RSV’s antioxidant capabilities in vision.


1995 ◽  
Vol 268 (4) ◽  
pp. F770-F777 ◽  
Author(s):  
M. G. Mohaupt ◽  
J. Schwobel ◽  
J. L. Elzie ◽  
G. S. Kannan ◽  
B. C. Kone

The effects of lipopolysaccharide (LPS) and/or inflammatory cytokines on the expression of inducible nitric oxide synthase (iNOS) were studied in mIMCD-3 cells, derived from the murine inner medullary collecting duct. Under basal conditions, the production of nitrite, a stable metabolite of NO, was negligible; however, incubation with tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IF-gamma) for 24 h resulted in a 12-fold increase in nitrite synthesis and the appearance of abundant iNOS mRNA and protein. The induction of nitrite production and iNOS mRNA was time dependent, requiring approximately 8 h for expression of significant levels of nitrite or iNOS mRNA. Coincubation with the transcription inhibitor actinomycin D or the translation inhibitor cycloheximide prevented the cytokine induction of iNOS mRNA and NO production, indicating that synthesis of intermediary proteins stimulated transcription of the iNOS gene. Nuclear run-on transcription demonstrated that the iNOS gene was transcriptionally inactive under basal conditions, but was markedly induced by TNF-alpha and IF-gamma. These results indicate that inflammatory cytokines stimulate NO production in mIMCD-3 cells by activating iNOS gene transcription in a process that requires new protein synthesis.


2007 ◽  
Vol 192 (1) ◽  
pp. 169-177 ◽  
Author(s):  
Marta Montolio ◽  
Montse Biarnés ◽  
Noèlia Téllez ◽  
Jessica Escoriza ◽  
Joan Soler ◽  
...  

Islets are particularly vulnerable in the initial days after transplantation when cell death results in the loss of more than half of the transplanted islet tissue. To determine whether a non-specific inflammation at the grafted site mediated by the local expression of inflammatory cytokines could play a role on the initial damage to transplanted islets, we studied the expressions of interleukin-1β (IL-1β) and inducible form of nitric oxide synthase (iNOS) after syngeneic islet transplantation. Insulin-treated streptozotocin-diabetic Lewis rats were syngeneically transplanted with 500 islets. Grafts were harvested 1, 3, or 7 days after transplantation, and the expressions of IL-1β and iNOS genes were determined by RT-PCR. IL-1β and iNOS mRNAs were detected in islets immediately after isolation, and were upregulated after transplantation. IL-1β mRNA was ninefold increased on day 1, was still sevenfold increased on day 3 after transplantation, and declined towards pretransplantation levels on day 7. iNOS mRNA showed a similar pattern of expression to that of IL-1β: on days 1 and 3 after transplantation it was 14-and 4-fold higher respectively than in freshly isolated islets. In addition, IL-1β and iNOS were identified in islet grafts and found to be produced mainly by CD68-positive macrophages. A low number of IL-1β- and iNOS-positive but CD68-negative cells were also identified suggesting that other cell types, in addition to macrophages, were involved in the expression of IL-1β and NO production in islet grafts. The finding of increased IL-1β and iNOS gene expressions in the initial days after islet transplantation and the presence of IL-β and iNOS proteins in the graft confirmed the presence of an early non-specific inflammatory response after islet transplantation. Overall, the data suggest that IL-1β plays a role in the extensive β-cell death found in the initial days after islet transplantation.


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