Cargando…

L-Ascorbate Attenuates the Endotoxin-Induced Production of Inflammatory Mediators by Inhibiting MAPK Activation and NF-κB Translocation in Cortical Neurons/Glia Cocultures

In response to acute insults to the central nervous system, such as pathogen invasion or neuronal injuries, glial cells become activated and secrete inflammatory mediators such as nitric oxide (NO), cytokines, and chemokines. This neuroinflammation plays a crucial role in the pathophysiology of chro...

Descripción completa

Detalles Bibliográficos
Autores principales: Huang, Ya-Ni, Lai, Chien-Cheng, Chiu, Chien-Tsai, Lin, Jhen-Jhe, Wang, Jia-Yi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4077707/
https://www.ncbi.nlm.nih.gov/pubmed/24983461
http://dx.doi.org/10.1371/journal.pone.0097276
_version_ 1782323638722101248
author Huang, Ya-Ni
Lai, Chien-Cheng
Chiu, Chien-Tsai
Lin, Jhen-Jhe
Wang, Jia-Yi
author_facet Huang, Ya-Ni
Lai, Chien-Cheng
Chiu, Chien-Tsai
Lin, Jhen-Jhe
Wang, Jia-Yi
author_sort Huang, Ya-Ni
collection PubMed
description In response to acute insults to the central nervous system, such as pathogen invasion or neuronal injuries, glial cells become activated and secrete inflammatory mediators such as nitric oxide (NO), cytokines, and chemokines. This neuroinflammation plays a crucial role in the pathophysiology of chronic neurodegenerative diseases. Endogenous ascorbate levels are significantly decreased among patients with septic encephalopathy. Using the bacterial endotoxin lipopolysaccharide (LPS) to induce neuroinflammation in primary neuron/glia cocultures, we investigated how L-ascorbate (vitamin C; Vit. C) affected neuroinflammation. LPS (100 ng/ml) induced the expression of inducible NO synthase (iNOS) and the production of NO, interleukin (IL)-6, and macrophage inflammatory protein-2 (MIP-2/CXCL2) in a time-dependent manner; however, cotreatment with Vit. C (5 or 10 mM) attenuated the LPS-induced iNOS expression and production of NO, IL-6, and MIP-2 production. The morphological features revealed after immunocytochemical staining confirmed that Vit. C suppressed LPS-induced astrocytic and microglial activation. Because Vit. C can be transported into neurons and glia via the sodium-dependent Vit. C transporter-2, we examined how Vit. C affected LPS-activated intracellular signaling in neuron/glia cocultures. The results indicated the increased activation (caused by phosphorylation) of mitogen-activated protein kinases (MAPKs), such as p38 at 30 min and extracellular signal-regulated kinases (ERKs) at 180 min after LPS treatment. The inhibition of p38 and ERK MAPK suppressed the LPS-induced production of inflammatory mediators. Vit. C also inhibited the LPS-induced activation of p38 and ERK. Combined treatments of Vit. C and the inhibitors of p38 and ERK yielded no additional inhibition compared with using the inhibitors alone, suggesting that Vit. C functions through the same signaling pathway (i.e., MAPK) as these inhibitors. Vit. C also reduced LPS-induced IκB-α degradation and NF-κB translocation. Thus, Vit. C suppressed the LPS-stimulated production of inflammatory mediators in neuron/glia cocultures by inhibiting the MAPK and NF-κB signaling pathways.
format Online
Article
Text
id pubmed-4077707
institution National Center for Biotechnology Information
language English
publishDate 2014
publisher Public Library of Science
record_format MEDLINE/PubMed
spelling pubmed-40777072014-07-03 L-Ascorbate Attenuates the Endotoxin-Induced Production of Inflammatory Mediators by Inhibiting MAPK Activation and NF-κB Translocation in Cortical Neurons/Glia Cocultures Huang, Ya-Ni Lai, Chien-Cheng Chiu, Chien-Tsai Lin, Jhen-Jhe Wang, Jia-Yi PLoS One Research Article In response to acute insults to the central nervous system, such as pathogen invasion or neuronal injuries, glial cells become activated and secrete inflammatory mediators such as nitric oxide (NO), cytokines, and chemokines. This neuroinflammation plays a crucial role in the pathophysiology of chronic neurodegenerative diseases. Endogenous ascorbate levels are significantly decreased among patients with septic encephalopathy. Using the bacterial endotoxin lipopolysaccharide (LPS) to induce neuroinflammation in primary neuron/glia cocultures, we investigated how L-ascorbate (vitamin C; Vit. C) affected neuroinflammation. LPS (100 ng/ml) induced the expression of inducible NO synthase (iNOS) and the production of NO, interleukin (IL)-6, and macrophage inflammatory protein-2 (MIP-2/CXCL2) in a time-dependent manner; however, cotreatment with Vit. C (5 or 10 mM) attenuated the LPS-induced iNOS expression and production of NO, IL-6, and MIP-2 production. The morphological features revealed after immunocytochemical staining confirmed that Vit. C suppressed LPS-induced astrocytic and microglial activation. Because Vit. C can be transported into neurons and glia via the sodium-dependent Vit. C transporter-2, we examined how Vit. C affected LPS-activated intracellular signaling in neuron/glia cocultures. The results indicated the increased activation (caused by phosphorylation) of mitogen-activated protein kinases (MAPKs), such as p38 at 30 min and extracellular signal-regulated kinases (ERKs) at 180 min after LPS treatment. The inhibition of p38 and ERK MAPK suppressed the LPS-induced production of inflammatory mediators. Vit. C also inhibited the LPS-induced activation of p38 and ERK. Combined treatments of Vit. C and the inhibitors of p38 and ERK yielded no additional inhibition compared with using the inhibitors alone, suggesting that Vit. C functions through the same signaling pathway (i.e., MAPK) as these inhibitors. Vit. C also reduced LPS-induced IκB-α degradation and NF-κB translocation. Thus, Vit. C suppressed the LPS-stimulated production of inflammatory mediators in neuron/glia cocultures by inhibiting the MAPK and NF-κB signaling pathways. Public Library of Science 2014-07-01 /pmc/articles/PMC4077707/ /pubmed/24983461 http://dx.doi.org/10.1371/journal.pone.0097276 Text en © 2014 Huang et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Huang, Ya-Ni
Lai, Chien-Cheng
Chiu, Chien-Tsai
Lin, Jhen-Jhe
Wang, Jia-Yi
L-Ascorbate Attenuates the Endotoxin-Induced Production of Inflammatory Mediators by Inhibiting MAPK Activation and NF-κB Translocation in Cortical Neurons/Glia Cocultures
title L-Ascorbate Attenuates the Endotoxin-Induced Production of Inflammatory Mediators by Inhibiting MAPK Activation and NF-κB Translocation in Cortical Neurons/Glia Cocultures
title_full L-Ascorbate Attenuates the Endotoxin-Induced Production of Inflammatory Mediators by Inhibiting MAPK Activation and NF-κB Translocation in Cortical Neurons/Glia Cocultures
title_fullStr L-Ascorbate Attenuates the Endotoxin-Induced Production of Inflammatory Mediators by Inhibiting MAPK Activation and NF-κB Translocation in Cortical Neurons/Glia Cocultures
title_full_unstemmed L-Ascorbate Attenuates the Endotoxin-Induced Production of Inflammatory Mediators by Inhibiting MAPK Activation and NF-κB Translocation in Cortical Neurons/Glia Cocultures
title_short L-Ascorbate Attenuates the Endotoxin-Induced Production of Inflammatory Mediators by Inhibiting MAPK Activation and NF-κB Translocation in Cortical Neurons/Glia Cocultures
title_sort l-ascorbate attenuates the endotoxin-induced production of inflammatory mediators by inhibiting mapk activation and nf-κb translocation in cortical neurons/glia cocultures
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4077707/
https://www.ncbi.nlm.nih.gov/pubmed/24983461
http://dx.doi.org/10.1371/journal.pone.0097276
work_keys_str_mv AT huangyani lascorbateattenuatestheendotoxininducedproductionofinflammatorymediatorsbyinhibitingmapkactivationandnfkbtranslocationincorticalneuronsgliacocultures
AT laichiencheng lascorbateattenuatestheendotoxininducedproductionofinflammatorymediatorsbyinhibitingmapkactivationandnfkbtranslocationincorticalneuronsgliacocultures
AT chiuchientsai lascorbateattenuatestheendotoxininducedproductionofinflammatorymediatorsbyinhibitingmapkactivationandnfkbtranslocationincorticalneuronsgliacocultures
AT linjhenjhe lascorbateattenuatestheendotoxininducedproductionofinflammatorymediatorsbyinhibitingmapkactivationandnfkbtranslocationincorticalneuronsgliacocultures
AT wangjiayi lascorbateattenuatestheendotoxininducedproductionofinflammatorymediatorsbyinhibitingmapkactivationandnfkbtranslocationincorticalneuronsgliacocultures