The TLR3 ligand polyI:C downregulates connexin 43 expression and function in astrocytes by a mechanism involving the NF‐κB and PI3 kinase pathways
The TLR3 ligand polyI:C downregulates connexin 43 expression and function in astrocytes by a mechanism involving the NF‐κB and PI3 kinase pathways
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DOI：
10.1002/glia.20418
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发表时间：
2006-12
期刊：
影响因子：
6.2
通讯作者：
Yongmei Zhao;Mark A. Rivieccio;S. Lutz;E. Scemes;C. Brosnan
中科院分区：
文献类型：
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作者：
Yongmei Zhao;Mark A. Rivieccio;S. Lutz;E. Scemes;C. Brosnan
Toll样受体3（TLR 3）是先天免疫应答的组成部分，对dsRNA病毒和病毒复制中间体产生应答。在这项研究中，我们发现用dsRNA模拟物聚肌苷酸-胞苷酸（pI：C）激活星形胶质细胞导致连接蛋白43（Cx43）mRNA和蛋白表达的丧失，同时上调离子型P2受体P2 X4 R的表达。对所涉及的信号通路的分析未能证明p38 MAP激酶、ERK或JNK信号通路的作用，而PI 3激酶/Akt通路的抑制剂有效地阻断了pI：C的作用。使用含有NF-κB超阻遏物（NF-κB SR）构建体或显性负性干扰素调节因子3（dnIRF 3）构建体的腺病毒载体显示，抑制两种转录因子也阻断了pI：C的作用。为了探索pI：C激活的功能后果，我们使用了P2 X4 R活性的成孔试验和间隙连接细胞间通讯（GJIC）的刮片加载试验。在对照或活化星形胶质细胞中均未检测到与功能性P2 X4 R表达一致的成孔活性。相反，在pI：C激活后丢失的静息细胞中检测到指示GJIC的稳健荧光黄转移。dnIRF 3构建体未能恢复GJIC，而NF-κB SR或NF-κB抑制剂BAY 11 - 7082和PI 3 K抑制剂LY 294002均显著逆转pI：C对GJ连接的影响。我们的结论是，星形胶质细胞中先天免疫反应的激活与GJIC的功能丧失有关，通过NF-κB和PI 3激酶的途径。© 2006 Wiley利斯公司
Toll‐like receptor 3 (TLR3) is a component of the innate immune response that responds to dsRNA viruses and virus replication intermediates. In this study we show that activation of astrocytes with the dsRNA mimetic polyinosinic‐cytidylic acid (pI:C) results in loss of expression of connexin43 (Cx43) mRNA and protein while upregulating the expression of the ionotropic P2 receptor P2X4R. Analysis of the signaling pathways involved failed to demonstrate a role for the p38 MAP kinase, ERK, or JNK signaling pathways whereas an inhibitor of the PI3 kinase/Akt pathway effectively blocked the action of pI:C. Using adenoviral vectors containing a super‐repressor of NF‐κB (NF‐κB SR) construct or a dominant negative interferon regulatory factor 3 (dnIRF3) construct showed that inhibition of both transcription factors also blocked the effects of pI:C. To explore the functional consequences of pI:C activation we used a pore‐forming assay for P2X4R activity and a scrape loading assay for gap junction intercellular communication (GJIC). No pore‐forming activity consistent with functional P2X4R expression was detected in either control or activated astrocytes. In contrast, robust Lucifer yellow transfer indicative of GJIC was detected in resting cells that was lost following pI:C activation. The dnIRF3 construct failed to restore GJIC whereas the NF‐κB SR or the NF‐κB inhibitor BAY11‐7082 and the PI3K inhibitor LY294002 all significantly reversed the effect of pI:C on GJ connectivity. We conclude that activation of the innate immune response in astrocytes is associated with functional loss of GJIC through a pathway involving NF‐κB and PI3 kinase. © 2006 Wiley‐Liss, Inc.