Astrocytes acquire resistance to iron-dependent oxidative stress upon proinflammatory activationReport as inadecuate




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Journal of Neuroinflammation

, 10:897

First Online: 28 October 2013Received: 07 February 2013Accepted: 10 October 2013

Abstract

BackgroundAstrocytes respond to local insults within the brain and the spinal cord with important changes in their phenotype. This process, overall known as -activation-, is observed upon proinflammatory stimulation and leads astrocytes to acquire either a detrimental phenotype, thereby contributing to the neurodegenerative process, or a protective phenotype, thus supporting neuronal survival. Within the mechanisms responsible for inflammatory neurodegeneration, oxidative stress plays a major role and has recently been recognized to be heavily influenced by changes in cytosolic iron levels. In this work, we investigated how activation affects the competence of astrocytes to handle iron overload and the ensuing oxidative stress.

MethodsCultures of pure cortical astrocytes were preincubated with proinflammatory cytokines interleukin-1β and tumor necrosis factor α or conditioned medium from lipopolysaccharide-activated microglia to promote activation and then exposed to a protocol of iron overload.

ResultsWe demonstrate that activated astrocytes display an efficient protection against iron-mediated oxidative stress and cell death. Based on this evidence, we performed a comprehensive biochemical and molecular analysis, including a transcriptomic approach, to identify the molecular basis of this resistance.

ConclusionsWe propose the protective phenotype acquired after activation not to involve the most common astrocytic antioxidant pathway, based on the Nrf2 transcription factor, but to result from a complex change in the expression and activity of several genes involved in the control of cellular redox state.

KeywordsAstrocyte activation Oxidative stress Iron Cytokines Nrf2 Microglia AbbreviationsCNSCentral nervous system

ROSReactive oxygen species

CM-H2DCFDA5-and-6-chloromethyl-2’,7’-dichlorodihydrofluorescein diacetate, acetyl ester

TMRMTetramethyl rhodamine methyl ester

BSOL-Buthionine-sulfoximine

GSHGlutathione

IL-1betaInterleukin-1beta

TNF-alphaTumor necrosis factor alpha

LPSLipopolysaccharide

MTT3-4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide

SOD2Mitochondrial superoxide dismutase

Nrf2-NFE2L2Nuclear factor erythroid-derived 2-like 2 gene

RTReverse transcription

qPCRQuantitative polymerase chain reaction

ANOVAAnalysis of variance

CK10 ng-ml IL-1β + 30 ng-ml TNFα

MCM−Quiescent microglia conditioned medium

MCM+LPS-activated microglia conditioned medium

TXNRD1Thioredoxin reductase

NOS2Nitric oxide synthase 2

EPHX2Epoxide hydrolase 2

AOX1Aldehyde oxidase 1.

Electronic supplementary materialThe online version of this article doi:10.1186-1742-2094-10-130 contains supplementary material, which is available to authorized users.

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Author: Romina Macco - Ilaria Pelizzoni - Alessandra Consonni - Ilaria Vitali - Giacomo Giacalone - Filippo Martinelli Boneschi - Fr

Source: https://link.springer.com/







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