Up-regulation of connexin43 correlates with increased synthetic activity and enhanced contractile differentiation in TGF-β-treated human aortic smooth muscle cells
Up-regulation of connexin43 correlates with increased synthetic activity and enhanced contractile differentiation in TGF-β-treated human aortic smooth muscle cells
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DOI：
10.1016/j.ejcb.2005.11.007
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发表时间：
2006-05-01
影响因子：
6.6
通讯作者：
Severs, Nicholas J.
中科院分区：
文献类型：
--
作者：
Rama, Aisha;Matsushita, Tsutomu;Severs, Nicholas J.
在动脉平滑肌细胞（SMC）中间隙连接蛋白连接蛋白43（Cx43）的上调在损伤和动脉粥样硬化中具有响应特征，与合成状态的表型转变平行。已知TGF-β 1在SMC分化和细胞外基质（ECM）合成中起作用，这是表型状态的关键特征。在这里，我们着手研究TGF-β 1对Cx43-缝隙连接表达的影响，与SMC分化、ECM合成和生长有关。通过免疫共聚焦显微镜和蛋白质印迹法分析了TGF-β 1处理48小时的原代人主动脉SMC中Cx43的表达，并通过显微注射溴化乙锭的细胞间转移评估了间隙连接通讯。同时，通过北方印迹法分析ECM组分α-1（I）和α 1（III）前胶原转录物的合成活性，通过免疫共聚焦显微镜和标志物平滑肌α-肌动蛋白、钙调蛋白和平滑肌重链亚型I（SM 1）的蛋白质印迹法评估收缩分化，并通过BrdU掺入法测量生长。我们的研究结果表明，TGF-β 1显着上调Cx43的表达和细胞间通讯，在演唱会增加表达的α-肌动蛋白，钙调蛋白和SM 1。伴随着收缩蛋白的表达，ECM合成增加而不是减少，TGF-β 1诱导两个前胶原转录显着上调。这些效应与生长无关。我们的结论是，在人主动脉平滑肌细胞，TGF-β 1治疗导致上调Cx43介导的缝隙连接通讯和增加合成活性，但有点矛盾的是，也增强收缩分化。(c)2006年Elsevier GmbH。All rights reserved.
Up-regulation of the gap-junctional protein connexin43 (Cx43) in arterial smooth muscle cells (SMCs) features in response to injury and in atherosclerosis, in parallel with phenotypic transition to the synthetic state. TGF-beta 1 is known to have a role in SMC differentiation and extracellular matrix (ECM) synthesis, key characteristics of phenotypic state. Here, we set out to examine the effects of TGF-beta 1 on Cx43-gap junction expression in relation to SMC differentiation, ECM synthesis and growth. Cx43 expression was analysed by immunoconfocal microscopy and Western blotting in primary human aortic SMCs treated with TGF-beta 1 over a 48-h period, with assessment of gap-junctional communication by cell-to-cell transfer of microinjected ethidium bromide. In parallel, synthetic activity was analysed by Northern blotting for ECM components alpha-1(I) and alpha 1(III) procollagen transcripts, contractile differentiation was assessed by immunoconfocal microscopy and Western blotting of the markers smooth muscle a-actin, calponin and smooth muscle heavy chain isoform I (SM1), and growth was measured by BrdU incorporation. Our results demonstrate that TGF-beta 1 significantly up-regulates Cx43 expression and intercellular communication, in concert with increased expression of alpha-actin, calponin and SM1. Concomitant with contractile protein expression, ECM synthesis was increased rather than decreased, TGF-beta 1 inducing a significant up-regulation of both procollagen transcripts. These effects were independent of growth. We conclude that in human aortic SMCs, TGF-beta 1 treatment leads to up-regulation of Cx43-mediated gap-junctional communication and increased synthetic activity yet, somewhat paradoxically, also enhanced contractile differentiation. (c) 2006 Elsevier GmbH. All rights reserved.