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Luteolin Inhibits Fibrillary β-Amyloid(1–40)-Induced Inflammation in a Human Blood-Brain Barrier Model by Suppressing the p38 MAPK-Mediated NF-κB Signaling Pathways

Amyloid-β peptides (Aβ) exist in several forms and are known as key modulators of Alzheimer’s disease (AD). Fibrillary Aβ (fAβ) has been found to disrupt the blood-brain barrier (BBB) by triggering and promoting inflammation. In this study, luteolin, a naturally occurring flavonoid that has shown be...

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Autores principales: Zhang, Jun-Xia, Xing, Jian-Guo, Wang, Lin-Lin, Jiang, Hai-Lun, Guo, Shui-Long, Liu, Rui
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6155314/
https://www.ncbi.nlm.nih.gov/pubmed/28245546
http://dx.doi.org/10.3390/molecules22030334
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author Zhang, Jun-Xia
Xing, Jian-Guo
Wang, Lin-Lin
Jiang, Hai-Lun
Guo, Shui-Long
Liu, Rui
author_facet Zhang, Jun-Xia
Xing, Jian-Guo
Wang, Lin-Lin
Jiang, Hai-Lun
Guo, Shui-Long
Liu, Rui
author_sort Zhang, Jun-Xia
collection PubMed
description Amyloid-β peptides (Aβ) exist in several forms and are known as key modulators of Alzheimer’s disease (AD). Fibrillary Aβ (fAβ) has been found to disrupt the blood-brain barrier (BBB) by triggering and promoting inflammation. In this study, luteolin, a naturally occurring flavonoid that has shown beneficial properties in the central nervous system, was evaluated as a potential agent to preserve barrier function and inhibit inflammatory responses at the BBB that was injured by fAβ(1–40). We established an in vitro BBB model by co-culturing human brain microvascular endothelial cells (hBMECs) and human astrocytes (hAs) under fAβ(1–40)-damaged conditions and investigated the effect of luteolin by analyzing cellular toxicity, barrier function, cytokine production and inflammation-related intracellular signaling pathways. Our results demonstrated that, in cells injured by fAβ(1–40), luteolin increased cell viability of hBMECs and hAs. The cytoprotection of the co-culture against the damage induced by fAβ(1–40) was also increased at both the apical and basolateral sides. Luteolin protected the barrier function by preserving transendothelial electrical resistance and relieving aggravated permeability in the human BBB model after being exposed to fAβ(1–40). Moreover, in both the apical and basolateral sides of the co-culture, luteolin reduced fAβ(1–40)-induced inflammatory mediator and cytokine production, including cyclooxygenase-2 (COX-2), tumor necrosis factor α (TNF-α), interleukin 1 β (IL-1β), interleukin 6 (IL-6), and interleukin 8 (IL-8), however it did not show sufficient effects on scavenging intracellular reactive oxygen species (ROS) in hBMECs and hAs. The mechanism of BBB protection against fAβ(1–40)-induced injury may be related to the regulation of inflammatory signal transduction, which involves inhibition of p38 mitogen-activated protein kinase (MAPK) activation, downregulation of phosphorylated inhibitory κB kinase (phosphor-IKK) levels, relief of inhibitory κB α (IκBα) degradation, blockage of nuclear factor κB (NF-κB) p65 nuclear translocation, and reduction of the release of inflammatory cytokines. Moreover, the employment of p38 MAPK and NF-κB inhibitors reversed luteolin-mediated barrier function and cytokine release. Taken together, luteolin may serve as a potential therapeutic agent for BBB protection by inhibiting inflammation following fAβ(1–40)-induced injury.
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spelling pubmed-61553142018-11-13 Luteolin Inhibits Fibrillary β-Amyloid(1–40)-Induced Inflammation in a Human Blood-Brain Barrier Model by Suppressing the p38 MAPK-Mediated NF-κB Signaling Pathways Zhang, Jun-Xia Xing, Jian-Guo Wang, Lin-Lin Jiang, Hai-Lun Guo, Shui-Long Liu, Rui Molecules Article Amyloid-β peptides (Aβ) exist in several forms and are known as key modulators of Alzheimer’s disease (AD). Fibrillary Aβ (fAβ) has been found to disrupt the blood-brain barrier (BBB) by triggering and promoting inflammation. In this study, luteolin, a naturally occurring flavonoid that has shown beneficial properties in the central nervous system, was evaluated as a potential agent to preserve barrier function and inhibit inflammatory responses at the BBB that was injured by fAβ(1–40). We established an in vitro BBB model by co-culturing human brain microvascular endothelial cells (hBMECs) and human astrocytes (hAs) under fAβ(1–40)-damaged conditions and investigated the effect of luteolin by analyzing cellular toxicity, barrier function, cytokine production and inflammation-related intracellular signaling pathways. Our results demonstrated that, in cells injured by fAβ(1–40), luteolin increased cell viability of hBMECs and hAs. The cytoprotection of the co-culture against the damage induced by fAβ(1–40) was also increased at both the apical and basolateral sides. Luteolin protected the barrier function by preserving transendothelial electrical resistance and relieving aggravated permeability in the human BBB model after being exposed to fAβ(1–40). Moreover, in both the apical and basolateral sides of the co-culture, luteolin reduced fAβ(1–40)-induced inflammatory mediator and cytokine production, including cyclooxygenase-2 (COX-2), tumor necrosis factor α (TNF-α), interleukin 1 β (IL-1β), interleukin 6 (IL-6), and interleukin 8 (IL-8), however it did not show sufficient effects on scavenging intracellular reactive oxygen species (ROS) in hBMECs and hAs. The mechanism of BBB protection against fAβ(1–40)-induced injury may be related to the regulation of inflammatory signal transduction, which involves inhibition of p38 mitogen-activated protein kinase (MAPK) activation, downregulation of phosphorylated inhibitory κB kinase (phosphor-IKK) levels, relief of inhibitory κB α (IκBα) degradation, blockage of nuclear factor κB (NF-κB) p65 nuclear translocation, and reduction of the release of inflammatory cytokines. Moreover, the employment of p38 MAPK and NF-κB inhibitors reversed luteolin-mediated barrier function and cytokine release. Taken together, luteolin may serve as a potential therapeutic agent for BBB protection by inhibiting inflammation following fAβ(1–40)-induced injury. MDPI 2017-02-24 /pmc/articles/PMC6155314/ /pubmed/28245546 http://dx.doi.org/10.3390/molecules22030334 Text en © 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Zhang, Jun-Xia
Xing, Jian-Guo
Wang, Lin-Lin
Jiang, Hai-Lun
Guo, Shui-Long
Liu, Rui
Luteolin Inhibits Fibrillary β-Amyloid(1–40)-Induced Inflammation in a Human Blood-Brain Barrier Model by Suppressing the p38 MAPK-Mediated NF-κB Signaling Pathways
title Luteolin Inhibits Fibrillary β-Amyloid(1–40)-Induced Inflammation in a Human Blood-Brain Barrier Model by Suppressing the p38 MAPK-Mediated NF-κB Signaling Pathways
title_full Luteolin Inhibits Fibrillary β-Amyloid(1–40)-Induced Inflammation in a Human Blood-Brain Barrier Model by Suppressing the p38 MAPK-Mediated NF-κB Signaling Pathways
title_fullStr Luteolin Inhibits Fibrillary β-Amyloid(1–40)-Induced Inflammation in a Human Blood-Brain Barrier Model by Suppressing the p38 MAPK-Mediated NF-κB Signaling Pathways
title_full_unstemmed Luteolin Inhibits Fibrillary β-Amyloid(1–40)-Induced Inflammation in a Human Blood-Brain Barrier Model by Suppressing the p38 MAPK-Mediated NF-κB Signaling Pathways
title_short Luteolin Inhibits Fibrillary β-Amyloid(1–40)-Induced Inflammation in a Human Blood-Brain Barrier Model by Suppressing the p38 MAPK-Mediated NF-κB Signaling Pathways
title_sort luteolin inhibits fibrillary β-amyloid(1–40)-induced inflammation in a human blood-brain barrier model by suppressing the p38 mapk-mediated nf-κb signaling pathways
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6155314/
https://www.ncbi.nlm.nih.gov/pubmed/28245546
http://dx.doi.org/10.3390/molecules22030334
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