Role of the JNK Signaling PathWay in Downregulation of Connexin43 by TNF-α in Human Corneal Fibroblasts
Role of the JNK Signaling PathWay in Downregulation of Connexin43 by TNF-α in Human Corneal Fibroblasts
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DOI：
10.3109/02713683.2013.798419
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发表时间：
2013-09-01
影响因子：
2
通讯作者：
Sonoda, Koh-Hei
中科院分区：
文献类型：
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作者：
Kimura, Kazuhiro;Orita, Tomoko;Sonoda, Koh-Hei
目的：促炎细胞因子如肿瘤坏死因子（TNF）-α可导致角膜炎症。角膜基质成纤维细胞通过间隙连接彼此连接。我们现在已经研究了有丝分裂原活化蛋白激酶（MAPK）信号通路在TNF-α诱导下调的差距连接蛋白connexin 43（Cx43）在人角膜fibroblasts.Materials和方法：培养的人角膜成纤维细胞暴露于TNF-α的存在或不存在的MAPK信号通路的抑制剂的作用。通过免疫荧光和免疫印迹分析评估Cx43的表达。缝隙连接细胞间通讯（GJIC）与染料偶联assay.Results：TNF-α减少了丰富的人角膜成纤维细胞中的Cx43（如通过免疫印迹分析所揭示的），以及诱导这种蛋白质的特异性染色的损失（如通过免疫荧光分析所揭示的）。c-Jun NH 2-末端激酶抑制剂（JNK抑制剂II）可减弱TNF-α的这些作用，但细胞外信号调节激酶（PD 98059）或p38 MAPK（SB 203580）的信号传导抑制剂不会减弱TNF-α的这些作用。JNK抑制剂II也减弱了TNF-α对GJIC.Conclusions的抑制作用：TNF-α对人角膜成纤维细胞中Cx43表达和GJIC的抑制作用至少部分由JNK信号通路介导，因此可能在角膜炎症中起作用。
Purpose/Aim: Proinflammatory cytokines such as tumor necrosis factor (TNF)-alpha contribute to corneal inflammation. Corneal stromal fibroblasts are connected to each other via gap junctions. We have now examined the role of mitogen-activated protein kinase (MAPK) signaling pathways in TNF-alpha-induced downregulation of the gap junction protein connexin43 (Cx43) in human corneal fibroblasts.Materials and Methods: Cultured human corneal fibroblasts were exposed to TNF-alpha in the absence or presence of inhibitors of MAPK signaling pathways. Expression of Cx43 was evaluated by immunofluorescence and immunoblot analyses. Gap-junctional intercellular communication (GJIC) was measured with a dye-coupling assay.Results: TNF-alpha reduced the abundance of Cx43 in human corneal fibroblasts (as revealed by immunoblot analysis) as well as induced the loss of specific staining for this protein (as revealed by immunofluorescence analysis). These effects of TNF-alpha were attenuated by an inhibitor of c-Jun NH2-terminal kinase (JNK inhibitor II) but not by inhibitors of signaling by extracellular signal-regulated kinase (PD98059) or by p38 MAPK (SB203580). JNK inhibitor II also attenuated the inhibitory effect of TNF-alpha on GJIC.Conclusions: The inhibitory effects of TNF-alpha on Cx43 expression and GJIC in human corneal fibroblasts are mediated, at least in part, by the JNK signaling pathway, which therefore likely plays a role in corneal inflammation.