scholarly journals Glutathione inhibits expression of the proinflammatory biomarker inducible nitric oxide synthase in hepatocytes

2018 ◽  
Vol 8 (12) ◽  
pp. 544
Author(s):  
Richi Nakatake ◽  
Masaya Kotsuka ◽  
Yuki Hashimoto ◽  
Masahiko Hatta ◽  
Morihiko Ishizaki ◽  
...  

Background: Intracellular glutathione (GSH) plays an important regulatory role in the host response to liver injury. However, there have been few scientific reports on the anti-inflammatory effects of GSH. In the inflamed liver, proinflammatory cytokines stimulate liver cells, followed by expression of inducible nitric oxide synthase (iNOS). Excessive nitric oxide (NO) levels produced by iNOS are one of the factors involved in liver injury. Therefore, inhibiting iNOS induction is important for preventing liver injury. This study aimed to investigate the protective effects of GSH on the liver by examining interleukin (IL)-1β-stimulated hepatocytes.Methods: Primary cultured rat hepatocytes were treated with IL-1β in the presence or absence of GSH. Induction of iNOS and its signaling pathway were analyzed.Results: Addition of GSH decreased IL-1β-induced iNOS protein and mRNA expression levels, which resulted in inhibition of NO production. GSH also decreased tumor necrosis factor (TNF)-α and IL-6 mRNA expression. GSH blocked “type I IL-1 receptor upregulation”, one of the essential signaling pathways for iNOS induction, through inactivation of an upstream kinase, phosphatidylinositol 3-kinase/Akt. In contrast, GSH had no effects on degradation of IκB and activation of NF-ĸB (nuclear translocation and its DNA binding). Transfection experiments revealed that GSH reduced iNOS mRNA levels at the promoter transactivation and mRNA stabilization steps. Delayed administration of GSH after IL-1β addition also inhibited iNOS induction. Conclusions: Our study suggests that GSH affects induction of inflammatory mediators, including iNOS and TNF-α, indicating its therapeutic potential for organ injuries, especially for the liver.Keywords: glutathione, inducible nitric oxide synthase, liver injury, primary cultured hepatocytes, type I interleukin-1 receptor, tumor necrosis factor-α

2018 ◽  
Vol 8 (3) ◽  
pp. 175 ◽  
Author(s):  
Richi Nakatake ◽  
Hiroya Iida ◽  
Morihiko Ishizaki ◽  
Kosuke Matsui ◽  
Yusuke Nakamura ◽  
...  

Background: Metformin is used to treat patients with type II diabetes. However, there are few scientific reports on its anti-inflammatory effects. In the inflamed liver, proinflammatory cytokines stimulate liver cells, followed by inducible nitric oxide synthase (iNOS) expression. Excessive NO levels produced by iNOS have been implicated as a factor in liver injury. As a result, it is essential to inhibit iNOS induction to prevent liver injury.Objective: This study aimed to investigate liver protective effects of metformin by examining interleukin (IL)-1β-stimulated hepatocytes. Methods: Primary cultured rat hepatocytes were treated with interleukin (IL)-1β in the presence or absence of metformin. iNOS induction and its signaling pathway were analyzed.Results: Metformin decreased iNOS protein and mRNA expression, resulting in the inhibition of hepatic NO production. Metformin also reduced tumor necrosis factor (TNF)-α and IL-6 mRNA expression. Metformin inhibited an essential signaling pathway for iNOS induction, type I IL-1 receptor upregulation. Transfection experiments revealed that metformin reduced iNOS mRNA levels through both promoter transactivation and mRNA stabilization. Delayed metformin administration after IL-1β addition also inhibited iNOS induction. Conclusions: Metformin affects the induction of inflammatory mediators including iNOS and TNF-α, demonstrating its therapeutic potential for organ injuries, including the liver.Keywords: metformin, inducible nitric oxide synthase, liver injury, primary cultured hepatocytes, type I interleukin-1 receptor, tumor necrosis factor-α 


2017 ◽  
Vol 7 (9) ◽  
pp. 716 ◽  
Author(s):  
Richi Nakatake ◽  
Hidehiko Hishikawa ◽  
Hideyuki Matushima ◽  
Yusuke Nakamura ◽  
Morihiko Ishizaki ◽  
...  

Background: Curcumin has beneficial effects on organ metabolism. However, there is little evidence that curcumin affects inflammatory mediators, such as tumor necrosis factor (TNF)-α and nitric oxide (NO). In an inflamed liver, proinflammatory cytokines stimulate liver cells, followed by the induction of inducible NO synthase (iNOS). Excessive NO produced by iNOS is one of the factors in liver injury. Therefore, inhibiting iNOS induction for preventing liver injury is important.Objective: This study aimed to investigate liver protective effects of curcumin by examining interleukin (IL)-1β-stimulated hepatocytes.Methods: Primary cultured rat hepatocytes were treated with IL-1β in the presence or absence of curcumin. Induction of NO production and iNOS, and the signaling pathway of iNOS were analyzed.Results: Simultaneous addition of IL-1β and curcumin decreased expression levels of iNOS protein and mRNA, resulting in inhibition of NO production. Curcumin also reduced mRNA expression of TNF-α and IL-6. Curcumin inhibited two essential signaling pathways for iNOS induction, NF-κB activation and type I IL-1 receptor upregulation. Transfection experiments revealed that curcumin reduced iNOS mRNA levels at the promoter activation and mRNA stabilization steps. Delayed administration of curcumin after IL-1β addition also inhibited iNOS induction.Conclusions: Curcumin affects induction of inflammatory mediators, such as iNOS and TNF-α, in part through the inhibition of NF-κB activation in hepatocytes. Curcumin may have therapeutic potential for organ injuries, including the liver.Key words: curcumin, inducible nitric oxide synthase, liver injury, primary cultured hepatocytes, nuclear factor-κB, type I interleukin-1 receptor, tumor necrosis factor-α. 


2018 ◽  
Vol 8 (3) ◽  
pp. 212 ◽  
Author(s):  
Yusuke Nakamura ◽  
Hiroya Iida ◽  
Richi Nakatake ◽  
Tatsuma Sakaguchi ◽  
Masaki Kaibori ◽  
...  

Background: L-Carnitine has protective effects on various injured organs. However, it has not been reported whether L-carnitine influences the induction of inducible nitric oxide synthase (iNOS) expression during inflammation. Nitric oxide (NO) produced by iNOS is an inflammatory indicator in organs which become inflamed, including the liver.Objective: This study aimed to examine whether L-carnitine influences the induction of iNOS gene expression in inflammatory cytokine-stimulated hepatocytes and the mechanisms involved in the action. Methods: L-Carnitine was added into the primary cultures of rat hepatocytes stimulated by interleukin-1β (an in vitro liver injury model). The production of NO and induction of iNOS and its signaling pathway were analyzed.Results: Transfection experiments with iNOS promoter-luciferase constructs revealed how L-carnitine inhibited iNOS mRNA synthesis activity and reduced its stability. In support of this observation, L-carnitine reduced iNOS mRNA and iNOS protein expression levels, resulting in reduced NO production. L-Carnitine blocked two essential pathways for iNOS induction: IκB kinase (IκB degradation/NF-κB activation) and phosphatidylinositol 3-kinase/Akt (type I IL-1 receptor upregulation).Conclusions: L-Carnitine inhibited the induction of inflammatory mediator iNOS, partially through inhibition of NF-κB activation, which demonstrated L-carnitine has protective effects in an in vitro liver injury model. L-Carnitine may have therapeutic potential for organ injuries, including the liver.Keywords: L-carnitine, hepatic encephalopathy, inducible nitric oxide synthase, liver injury, primary cultured hepatocytes, nuclear factor-κB, type I interleukin-1 receptor 


Hepatology ◽  
2002 ◽  
Vol 35 (2) ◽  
pp. 289-298 ◽  
Author(s):  
Mohammed Bourdi ◽  
Yasuhiro Masubuchi ◽  
Timothy P. Reilly ◽  
Hamid R. Amouzadeh ◽  
Jackie L. Martin ◽  
...  

2004 ◽  
Vol 41 (5) ◽  
pp. 773-781 ◽  
Author(s):  
Reto Guler ◽  
Maria L. Olleros ◽  
Dominique Vesin ◽  
Roumen Parapanov ◽  
Christian Vesin ◽  
...  

2006 ◽  
Vol 291 (3) ◽  
pp. F567-F577 ◽  
Author(s):  
Li-Mei Chen ◽  
Cindy Wang ◽  
Mengqian Chen ◽  
Matthew R. Marcello ◽  
Julie Chao ◽  
...  

Prostasin is a glycosylphosphatidylinositol-anchored serine protease, with epithelial sodium channel activation and tumor invasion suppression activities. We identified the bladder as an expression site of prostasin. In the mouse, prostasin mRNA expression was detected by reverse transcription and real-time polymerase chain reaction in the bladder, and the prostasin protein was localized by immunohistochemistry in the urothelial cells. In mice injected intraperitoneally with bacterial lipopolysaccharide (LPS), bladder prostasin mRNA expression was downregulated, whereas the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interferon-γ (IFN-γ), TNF-α, IL-1β, and IL-6 was upregulated. Viral promoter-driven expression of the human prostasin homolog in the bladder of transgenic mice attenuated the LPS induction of iNOS but did not abolish the induction. LPS induction of COX-2, TNF-α, IL-1β, and IL-6 expression, however, was not reduced by prostasin transgene expression. Liposome-mediated delivery of prostasin-expressing plasmid into mouse bladder produced similar attenuation effects on LPS-induced iNOS expression, while not affecting COX-2 or cytokine induction. Mice receiving plasmid expressing a catalytic mutant prostasin did not manifest the iNOS induction attenuation phenotype. We propose a proteolytic mechanism for prostasin to intercept cytokine signaling during LPS-induced bladder inflammation.


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