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Icaritin inhibits neuroinflammation in a rat cerebral ischemia model by regulating microglial polarization through the GPER–ERK–NF-κB signaling pathway

BACKGROUND: Activated microglia play a key role in initiating the inflammatory cascade following ischemic stroke and exert proinflammatory or anti-inflammatory effects, depending on whether they are polarized toward the M1 or M2 phenotype. The present study investigated the regulatory effect of icar...

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Autores principales: Yu, Zining, Su, Guangjun, Zhang, Limei, Liu, Gaigai, Zhou, Yonggang, Fang, Shicai, Zhang, Qian, Wang, Tianyun, Huang, Cheng, Huang, Zhihua, Li, Liangdong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9706854/
https://www.ncbi.nlm.nih.gov/pubmed/36447154
http://dx.doi.org/10.1186/s10020-022-00573-7
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author Yu, Zining
Su, Guangjun
Zhang, Limei
Liu, Gaigai
Zhou, Yonggang
Fang, Shicai
Zhang, Qian
Wang, Tianyun
Huang, Cheng
Huang, Zhihua
Li, Liangdong
author_facet Yu, Zining
Su, Guangjun
Zhang, Limei
Liu, Gaigai
Zhou, Yonggang
Fang, Shicai
Zhang, Qian
Wang, Tianyun
Huang, Cheng
Huang, Zhihua
Li, Liangdong
author_sort Yu, Zining
collection PubMed
description BACKGROUND: Activated microglia play a key role in initiating the inflammatory cascade following ischemic stroke and exert proinflammatory or anti-inflammatory effects, depending on whether they are polarized toward the M1 or M2 phenotype. The present study investigated the regulatory effect of icaritin (ICT) on microglial polarization in rats after cerebral ischemia/reperfusion injury (CI/RI) and explored the possible anti-inflammatory mechanisms of ICT. METHODS: A rat model of transient middle cerebral artery occlusion (tMCAO) was established. Following treatment with ICT, a G protein-coupled estrogen receptor (GPER) inhibitor or an extracellular signal-regulated kinase (ERK) inhibitor, the Garcia scale and rotarod test were used to assess neurological and locomotor function. 2,3,5-Triphenyltetrazolium chloride (TTC) and Fluoro-Jade C (FJC) staining were used to evaluate the infarct volume and neuronal death. The levels of inflammatory factors in the ischemic penumbra were evaluated using enzyme-linked immunosorbent assays (ELISAs). In addition, western blotting, immunofluorescence staining and quantitative PCR (qPCR) were performed to measure the expression levels of markers of different microglial phenotypes and proteins related to the GPER–ERK–nuclear factor kappa B (NF-κB) signaling pathway. RESULTS: ICT treatment significantly decreased the cerebral infarct volume, brain water content and fluorescence intensity of FJC; improved the Garcia score; increased the latency to fall and rotation speed in the rotarod test; decreased the levels of interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), Iba1, CD40, CD68 and p-P65-NF-κB; and increased the levels of CD206 and p-ERK. U0126 (an inhibitor of ERK) and G15 (a selective antagonist of GPER) antagonized these effects. CONCLUSIONS: These findings indicate that ICT plays roles in inhibiting the inflammatory response and achieving neuroprotection by regulating GPER–ERK–NF-κB signaling and then inhibiting microglial activation and M1 polarization while promoting M2 polarization, which provides a new therapeutic for against cerebral ischemic stroke. GRAPHICAL ABSTRACT: [Image: see text]
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spelling pubmed-97068542022-11-30 Icaritin inhibits neuroinflammation in a rat cerebral ischemia model by regulating microglial polarization through the GPER–ERK–NF-κB signaling pathway Yu, Zining Su, Guangjun Zhang, Limei Liu, Gaigai Zhou, Yonggang Fang, Shicai Zhang, Qian Wang, Tianyun Huang, Cheng Huang, Zhihua Li, Liangdong Mol Med Research Article BACKGROUND: Activated microglia play a key role in initiating the inflammatory cascade following ischemic stroke and exert proinflammatory or anti-inflammatory effects, depending on whether they are polarized toward the M1 or M2 phenotype. The present study investigated the regulatory effect of icaritin (ICT) on microglial polarization in rats after cerebral ischemia/reperfusion injury (CI/RI) and explored the possible anti-inflammatory mechanisms of ICT. METHODS: A rat model of transient middle cerebral artery occlusion (tMCAO) was established. Following treatment with ICT, a G protein-coupled estrogen receptor (GPER) inhibitor or an extracellular signal-regulated kinase (ERK) inhibitor, the Garcia scale and rotarod test were used to assess neurological and locomotor function. 2,3,5-Triphenyltetrazolium chloride (TTC) and Fluoro-Jade C (FJC) staining were used to evaluate the infarct volume and neuronal death. The levels of inflammatory factors in the ischemic penumbra were evaluated using enzyme-linked immunosorbent assays (ELISAs). In addition, western blotting, immunofluorescence staining and quantitative PCR (qPCR) were performed to measure the expression levels of markers of different microglial phenotypes and proteins related to the GPER–ERK–nuclear factor kappa B (NF-κB) signaling pathway. RESULTS: ICT treatment significantly decreased the cerebral infarct volume, brain water content and fluorescence intensity of FJC; improved the Garcia score; increased the latency to fall and rotation speed in the rotarod test; decreased the levels of interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), Iba1, CD40, CD68 and p-P65-NF-κB; and increased the levels of CD206 and p-ERK. U0126 (an inhibitor of ERK) and G15 (a selective antagonist of GPER) antagonized these effects. CONCLUSIONS: These findings indicate that ICT plays roles in inhibiting the inflammatory response and achieving neuroprotection by regulating GPER–ERK–NF-κB signaling and then inhibiting microglial activation and M1 polarization while promoting M2 polarization, which provides a new therapeutic for against cerebral ischemic stroke. GRAPHICAL ABSTRACT: [Image: see text] BioMed Central 2022-11-26 /pmc/articles/PMC9706854/ /pubmed/36447154 http://dx.doi.org/10.1186/s10020-022-00573-7 Text en © The Author(s) 2022 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Research Article
Yu, Zining
Su, Guangjun
Zhang, Limei
Liu, Gaigai
Zhou, Yonggang
Fang, Shicai
Zhang, Qian
Wang, Tianyun
Huang, Cheng
Huang, Zhihua
Li, Liangdong
Icaritin inhibits neuroinflammation in a rat cerebral ischemia model by regulating microglial polarization through the GPER–ERK–NF-κB signaling pathway
title Icaritin inhibits neuroinflammation in a rat cerebral ischemia model by regulating microglial polarization through the GPER–ERK–NF-κB signaling pathway
title_full Icaritin inhibits neuroinflammation in a rat cerebral ischemia model by regulating microglial polarization through the GPER–ERK–NF-κB signaling pathway
title_fullStr Icaritin inhibits neuroinflammation in a rat cerebral ischemia model by regulating microglial polarization through the GPER–ERK–NF-κB signaling pathway
title_full_unstemmed Icaritin inhibits neuroinflammation in a rat cerebral ischemia model by regulating microglial polarization through the GPER–ERK–NF-κB signaling pathway
title_short Icaritin inhibits neuroinflammation in a rat cerebral ischemia model by regulating microglial polarization through the GPER–ERK–NF-κB signaling pathway
title_sort icaritin inhibits neuroinflammation in a rat cerebral ischemia model by regulating microglial polarization through the gper–erk–nf-κb signaling pathway
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9706854/
https://www.ncbi.nlm.nih.gov/pubmed/36447154
http://dx.doi.org/10.1186/s10020-022-00573-7
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