Connexin45 regulates endothelial-induced mesenchymal cell differentiation toward a mural cell phenotype.
Connexin45 regulates endothelial-induced mesenchymal cell differentiation toward a mural cell phenotype.
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DOI：
10.1161/atvbaha.112.255950
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发表时间：
2013-02
期刊：
影响因子：
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通讯作者：
Hirschi KK
中科院分区：
文献类型：
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作者：
Fang JS;Dai C;Kurjiaka DT;Burt JM;Hirschi KK
缺乏连接蛋白45(Cx45)、Cx43或Cx40和Cx37的动物都有胚胎或出生后致命的血管表型。我们开发了一个血管组装的体外模型，以剖析这些连接蛋白在这一过程中的具体作用。在此之前，我们已经证明内皮细胞和间充质细胞之间的异细胞缝隙连接通道的形成是转化生长因子-β激活和内皮诱导的壁细胞分化所必需的，并且含有Cx43的通道支持这些过程。发育研究表明，Cx45在胚胎发育过程中是壁细胞发育所必需的，尽管它的确切作用还没有被描述。本研究的重点是探讨Cx45在内皮诱导的壁细胞分化中的作用。我们创造了在Cx43缺失的间充质细胞(ReCx45)中稳定表达Cx45的壁细胞前体细胞，并使用我们的体外血管组装模型来评估这种Cx支持内皮诱导的壁细胞分化的能力。荧光黄染料注射和双全细胞膜片钳显示，功能缝隙连接显示出在ReCx45转染体之间以及ReCx45与内皮细胞之间形成的含有Cx45的通道的特性。含Cx45的异细胞缝隙连接通道能够激活转化生长因子-β，并促进间充质前体细胞壁细胞特异性蛋白的上调。这些研究揭示了Cx45在调节内皮诱导的壁细胞分化中的关键作用，这与Cx45缺陷胚胎的表型一致，这些胚胎表现出转化生长因子-β的异常调节和缺乏壁细胞的发育。
Animals deficient for connexin 45 (Cx45), Cx43, or Cx40 and Cx37 all suffer embryonic or post-natal lethal vascular phenotypes. We developed an in vitro model of blood vessel assembly to dissect the specific roles of these connexins in this process. Previously, we showed that heterocellular gap junction channel formation between endothelial and mesenchymal cells is required for TGF-β activation and endothelial-induced mural cell differentiation, and that Cx43-containing channels support these processes. Developmental studies suggest that Cx45 is required for mural cell development during embryogenesis, although its exact role was not delineated. The focus of this study was to investigate the role of Cx45 in endothelial-induced mural cell differentiation. We created mural cell precursors that stably express only Cx45 in Cx43-deficient mesenchymal cells (ReCx45), and used our in vitro model of blood vessel assembly to assess the capacity of this Cx to support endothelial-induced mural cell differentiation. Lucifer Yellow dye injection and dual whole-cell patch clamping revealed that functional gap junctions exhibiting properties of Cx45-containing channels formed amongst ReCx45 transfectants, and between ReCx45 and endothelial cells. Heterocellular Cx45-containing gap junction channels enabled TGF-β activation, and promoted the upregulation of mural cell-specific proteins in the mesenchymal precursors. These studies reveal a critical role for Cx45 in the regulation of endothelial-induced mural cell differentiation, which is consistent with the phenotype of Cx45-deficient embryos that exhibit dysregulated TGF-β and lack mural cell development.