Suppressive effects of nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression by Citrus reticulata extract in RAW 264.7 macrophage cells

2007 ◽  
Vol 45 (8) ◽  
pp. 1545-1550 ◽  
Author(s):  
Kyung Hee Jung ◽  
Eunyoung Ha ◽  
Mi Ja Kim ◽  
Hye-Jin Won ◽  
Long Tai Zheng ◽  
...  
2008 ◽  
Vol 295 (1) ◽  
pp. L96-L103 ◽  
Author(s):  
Viktor Brovkovych ◽  
Xiao-Pei Gao ◽  
Evan Ong ◽  
Svitlana Brovkovych ◽  
Marie-Luise Brennan ◽  
...  

The myeloperoxidase (MPO)-hydrogen peroxide-halide system is an efficient oxygen-dependent antimicrobial component of polymorphonuclear leukocyte (PMN)-mediated host defense. However, MPO deficiency results in few clinical consequences indicating the activation of compensatory mechanisms. Here, we determined possible mechanisms protecting the host using MPO−/−mice challenged with live gram-negative bacterium Escherichia coli. We observed that MPO−/−mice unexpectedly had improved survival compared with wild-type (WT) mice within 5–12 h after intraperitoneal E. coli challenge. Lungs of MPO−/−mice also demonstrated lower bacterial colonization and markedly attenuated increases in microvascular permeability and edema formation after E. coli challenge compared with WT. However, PMN sequestration in lungs of both groups was similar. Basal inducible nitric oxide synthase (iNOS) expression was significantly elevated in lungs and PMNs of MPO−/−mice, and NO production was increased two- to sixfold compared with WT. Nitrotyrosine levels doubled in lungs of WT mice within 1 h after E. coli challenge but did not change in MPO−/−mice. Inhibition of iNOS in MPO−/−mice significantly increased lung edema and reduced their survival after E. coli challenge, but iNOS inhibitor had the opposite effect in WT mice. Thus augmented iNOS expression and NO production in MPO−/−mice compensate for the lack of HOCl-mediated bacterial killing, and the absence of MPO-derived oxidants mitigates E. coli sepsis-induced lung inflammation and injury.


2016 ◽  
Vol 41 (3) ◽  
Author(s):  
Ayşe Nalbantsoy ◽  
Mert Karış ◽  
Leyla Karakaya ◽  
Yurdanur Akgül

AbstractObjective: The aim of this study is to investigate the in vitro cytotoxicity and iNOS (inducible nitric oxide synthase) inhibitory, and antioxidant activity in order to assess the traditional usage of Liquidambar orientalis Mill resin extract.Methods: Different solvent extracts of Liquidambar orientalis Mill resin were prepared. The cytotoxicity of extracts was determined using MTT (3-(4,5-dimethyl-2-thiazolyl)- 2,5-diphenyl-2H-tetrazoliumbromide) assay. HeLa (Human cervix adenocarcinoma), A-549 (Human alveolar adenocarcinoma), MCF-7 (Human breast adenocarcinoma), CaCo-2 (Human colon colorectal adenocarcinoma), mPANC96 (Human pancreas adenocarcinoma), PC-3 (Human prostate adenocarcinoma), U87MG (Human glioblastoma- astrocytoma) and as a normal cell line HEK293 (Human embryonic kidney cells) and Vero (African green monkey kidney epithelial cells) were used for testing cytotoxicity. RAW 264.7 (murine macrophage cell lines) was used to determine the inhibition levels of inducible nitric oxide synthase (iNOS). HL-60 (human acute myeloid leukemia) was used to determine antioxidant activity as DCF production per cent.Results: Hexane, dichloromethane, methanol and water extracts were prepared, and their iNOS inhibitory, cytotoxic and antioxidant activity were investigated. The estimated IC50 values of extracts varied from 6.68 to 48.90 μg/ ml after treatment with different doses of extracts for 48 h. Inhibition of the hexane, dichloromethane, methanol, and water extracts on LPS-induced NO production in RAW 264.7 macrophage were showed that the all extracts inhibited NO production in activated RAW 264.7 cells, except methanol extract. Hexane, dichloromethane and methanol extracts inhibited NO production with ICConclusion: This study is the first report showing the potential of Liquidambar orientalis Mill resin extracts for cytotoxicity, iNOS inhibition and the antioxidant activity as an alternative therapeutic approach for traditional uses. The results demonstrated that Liquidambar orientalis dichloromethane resin extracts showed strongest cytotoxic effect while all extracts except methanolic extracts exhibited moderate iNOS inhibition. All extracts other than hexane have a potent antioxidant effect in the cellular-based assay. In conclusion, further studies should focus on the purification of the active components of this extracts and to investigate the possible mode of action to obtain a better understanding of their potential use as cytotoxic, anti-inflammatory and antioxidant agents.


2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Rafael Simone Saia ◽  
Fabíola Leslie Mestriner ◽  
Giuliana Bertozi ◽  
Fernando Queiróz Cunha ◽  
Evelin Capellari Cárnio

Cholecystokinin (CCK) was first described as a gastrointestinal hormone. However, apart from its gastrointestinal effects, studies have described that CCK also plays immunoregulatory roles. Taking in account the involvement of inducible nitric oxide synthase- (iNOS-) derived NO in the sepsis context, the present study was undertaken to investigate the role of CCK on iNOS expression in LPS-activated peritoneal macrophages. Our results revealed that CCK reduces NO production and attenuates the iNOS mRNA expression and protein formation. Furthermore, CCK inhibited the nuclear factor- (NF-)κB pathway reducing IκBαdegradation and minor p65-dependent translocation to the nucleus. Moreover, CCK restored the intracellular cAMP content activating the protein kinase A (PKA) pathway, which resulted in a negative modulatory role on iNOS expression. In peritoneal macrophages, the CCK-1R expression, but not CCK-2R, was predominant and upregulated by LPS. The pharmacological studies confirmed that CCK-1R subtype is the major receptor responsible for the biological effects of CCK. These data suggest an anti-inflammatory role for the peptide CCK in modulating iNOS-derived NO synthesis, possibly controlling the macrophage activation through NF-κB, cAMP-PKA, and CCK-1R pathways. Based on these findings, CCK could be used as an adjuvant agent to modulate the inflammatory response and prevent systemic complications commonly found during sepsis.


1999 ◽  
Vol 277 (3) ◽  
pp. L636-L644 ◽  
Author(s):  
Giovanni Cucchiaro ◽  
Arthur H. Tatum ◽  
Michael C. Brown ◽  
Enrico M. Camporesi ◽  
John W. Daucher ◽  
...  

The effect of hyperoxia on nitric oxide (NO) production in intact animals is unknown. We described the effects of hyperoxia on inducible nitric oxide synthase (iNOS) expression and NO production in the lungs of rats exposed to high concentrations of oxygen. Animals were placed in sealed Plexiglas chambers and were exposed to either 85% oxygen (hyperoxic group) or 21% oxygen (negative control group). Animals were anesthetized after 24 and 72 h of exposure and were ventilated via a tracheotomy. We measured NO production in exhaled air (ENO) by chemiluminescence. The lungs were then harvested and processed for detection of iNOS by immunohistochemistry and Western blotting analysis. The same experiments were repeated in animals exposed to hyperoxia for 72 h after they were infused with l-arginine. We used rats that were injected intraperitoneally with Escherichia coli lipopolysaccharide to induce septic shock as a positive control group. Hyperoxia and septic shock induced expression of iNOS in the lung. However, ENO was elevated only in septic shock rats but was normal in the hyperoxic group. Exogenous infusion of l-arginine after hyperoxia did not increase ENO. To exclude the possibility that in the hyperoxic group NO was scavenged by oxygen radicals to form peroxynitrite, lungs were studied by immunohistochemistry for the detection of nitrotyrosine. Nitrotyrosine was found in septic shock animals but not in the hyperoxic group, further suggesting that NO is not synthesized in rats exposed to hyperoxia. We conclude that hyperoxia induces iNOS expression in the lung without an increase in NO concentration in the exhaled air.


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