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Nitrosative stress and nitrated proteins in trichloroethene-mediated autoimmunity.

Wang G, Wang J, Luo X, Ansari GA, Khan MF - PLoS ONE (2014)

Bottom Line: TCE exposure led to significant increases in serum anti-nuclear and anti-histone antibodies together with significant induction of iNOS and increased formation of nitrotyrosine (NT) in sera and livers.Furthermore, TCE exposure led to decreased GSH levels and increased activation of NF-κB.These findings provide support to the role of nitrosative stress in TCE-mediated autoimmune response and identify specific nitrated proteins which could have autoimmune potential.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America.

ABSTRACT
Exposure to trichloroethene (TCE), a ubiquitous environmental contaminant, has been linked to a variety of autoimmune diseases (ADs) including SLE, scleroderma and hepatitis. Mechanisms involved in the pathogenesis of ADs are largely unknown. Earlier studies from our laboratory in MRL+/+ mice suggested the contribution of oxidative/nitrosative stress in TCE-induced autoimmunity, and N-acetylcysteine (NAC) supplementation provided protection by attenuating oxidative stress. This study was undertaken to further evaluate the contribution of nitrosative stress in TCE-mediated autoimmunity and to identify proteins susceptible to nitrosative stress. Groups of female MRL +/+ mice were given TCE, NAC or TCE + NAC for 6 weeks (TCE, 10 mmol/kg, i.p., every 4th day; NAC, ∼ 250 mg/kg/day via drinking water). TCE exposure led to significant increases in serum anti-nuclear and anti-histone antibodies together with significant induction of iNOS and increased formation of nitrotyrosine (NT) in sera and livers. Proteomic analysis identified 14 additional nitrated proteins in the livers of TCE-treated mice. Furthermore, TCE exposure led to decreased GSH levels and increased activation of NF-κB. Remarkably, NAC supplementation not only ameliorated TCE-induced nitrosative stress as evident from decreased iNOS, NT, nitrated proteins, NF-κB p65 activation and increased GSH levels, but also the markers of autoimmunity, as evident from decreased levels of autoantibodies in the sera. These findings provide support to the role of nitrosative stress in TCE-mediated autoimmune response and identify specific nitrated proteins which could have autoimmune potential. Attenuation of TCE-induced autoimmunity in mice by NAC provides an approach for designing therapeutic strategies.

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Protein expression (A) and phosphorylation (B) of NF-κB p65 in the livers of MRL+/+ mice treated with TCE, NAC or TCE+NAC for 6 weeks.The values are means ± SD. *p<0.05 vs. controls; #p<0.05 vs. TCE-treated mice. β-actin was used as loading control.
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pone-0098660-g004: Protein expression (A) and phosphorylation (B) of NF-κB p65 in the livers of MRL+/+ mice treated with TCE, NAC or TCE+NAC for 6 weeks.The values are means ± SD. *p<0.05 vs. controls; #p<0.05 vs. TCE-treated mice. β-actin was used as loading control.

Mentions: NF-κB has been shown to be involved in a number of ADs as a critical regulator of a variety of pro-inflammatory genes. Recent reports demonstrated that NF-κB may regulate iNOS expression and NO production [49]–[51]. NAC has been shown to modulate inflammatory responses through signaling pathways that control pro-inflammatory NF-κB activation [29], [52]. Since the results of this study show significantly increased iNOS protein and mRNA expression following TCE exposure, it was, therefore, of interest to analyze NF-κB activation. NF-κB p65 expression in livers was determined by Western blot analysis. Fig. 4A shows a significant increase of ∼1.9 fold in NF-κB p65 levels in TCE-treated mice in comparison to the controls, and their attenuation following NAC supplementation. To further evaluate the activation of NF-κB p65, phosphorylation of NF-κB p65 in the livers was analyzed as shown in Fig. 4B. The p-NF-κB p65 was remarkably elevated (3.6 fold) in the livers of TCE-treated mice and attenuated following NAC supplementation.


Nitrosative stress and nitrated proteins in trichloroethene-mediated autoimmunity.

Wang G, Wang J, Luo X, Ansari GA, Khan MF - PLoS ONE (2014)

Protein expression (A) and phosphorylation (B) of NF-κB p65 in the livers of MRL+/+ mice treated with TCE, NAC or TCE+NAC for 6 weeks.The values are means ± SD. *p<0.05 vs. controls; #p<0.05 vs. TCE-treated mice. β-actin was used as loading control.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4043737&req=5

pone-0098660-g004: Protein expression (A) and phosphorylation (B) of NF-κB p65 in the livers of MRL+/+ mice treated with TCE, NAC or TCE+NAC for 6 weeks.The values are means ± SD. *p<0.05 vs. controls; #p<0.05 vs. TCE-treated mice. β-actin was used as loading control.
Mentions: NF-κB has been shown to be involved in a number of ADs as a critical regulator of a variety of pro-inflammatory genes. Recent reports demonstrated that NF-κB may regulate iNOS expression and NO production [49]–[51]. NAC has been shown to modulate inflammatory responses through signaling pathways that control pro-inflammatory NF-κB activation [29], [52]. Since the results of this study show significantly increased iNOS protein and mRNA expression following TCE exposure, it was, therefore, of interest to analyze NF-κB activation. NF-κB p65 expression in livers was determined by Western blot analysis. Fig. 4A shows a significant increase of ∼1.9 fold in NF-κB p65 levels in TCE-treated mice in comparison to the controls, and their attenuation following NAC supplementation. To further evaluate the activation of NF-κB p65, phosphorylation of NF-κB p65 in the livers was analyzed as shown in Fig. 4B. The p-NF-κB p65 was remarkably elevated (3.6 fold) in the livers of TCE-treated mice and attenuated following NAC supplementation.

Bottom Line: TCE exposure led to significant increases in serum anti-nuclear and anti-histone antibodies together with significant induction of iNOS and increased formation of nitrotyrosine (NT) in sera and livers.Furthermore, TCE exposure led to decreased GSH levels and increased activation of NF-κB.These findings provide support to the role of nitrosative stress in TCE-mediated autoimmune response and identify specific nitrated proteins which could have autoimmune potential.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America.

ABSTRACT
Exposure to trichloroethene (TCE), a ubiquitous environmental contaminant, has been linked to a variety of autoimmune diseases (ADs) including SLE, scleroderma and hepatitis. Mechanisms involved in the pathogenesis of ADs are largely unknown. Earlier studies from our laboratory in MRL+/+ mice suggested the contribution of oxidative/nitrosative stress in TCE-induced autoimmunity, and N-acetylcysteine (NAC) supplementation provided protection by attenuating oxidative stress. This study was undertaken to further evaluate the contribution of nitrosative stress in TCE-mediated autoimmunity and to identify proteins susceptible to nitrosative stress. Groups of female MRL +/+ mice were given TCE, NAC or TCE + NAC for 6 weeks (TCE, 10 mmol/kg, i.p., every 4th day; NAC, ∼ 250 mg/kg/day via drinking water). TCE exposure led to significant increases in serum anti-nuclear and anti-histone antibodies together with significant induction of iNOS and increased formation of nitrotyrosine (NT) in sera and livers. Proteomic analysis identified 14 additional nitrated proteins in the livers of TCE-treated mice. Furthermore, TCE exposure led to decreased GSH levels and increased activation of NF-κB. Remarkably, NAC supplementation not only ameliorated TCE-induced nitrosative stress as evident from decreased iNOS, NT, nitrated proteins, NF-κB p65 activation and increased GSH levels, but also the markers of autoimmunity, as evident from decreased levels of autoantibodies in the sera. These findings provide support to the role of nitrosative stress in TCE-mediated autoimmune response and identify specific nitrated proteins which could have autoimmune potential. Attenuation of TCE-induced autoimmunity in mice by NAC provides an approach for designing therapeutic strategies.

Show MeSH
Related in: MedlinePlus