L-type calcium channel expression depends on the differentiated state of vascular smooth muscle cells
L-type calcium channel expression depends on the differentiated state of vascular smooth muscle cells
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DOI：
10.1096/fasebj.12.7.593
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发表时间：
1998-05-01
期刊：
影响因子：
4.8
通讯作者：
Haller, H
中科院分区：
文献类型：
--
作者：
Gollasch, M;Haase, H;Haller, H
尽管人们对血管平滑肌细胞(VSMC)的分化有浓厚的兴趣，但目前还没有关于这些细胞中离子通道的差异调控的信息。由于L钙通道在其他细胞类型中的表达受细胞分化的影响，我们验证了L-C类钙通道是血管平滑肌细胞特异性分化标志物的假说，并且这些通道的表达取决于细胞的分化状态。我们使用表达功能性L钙通道的大鼠主动脉(A7r5)血管平滑肌细胞，在不同的培养液中通过细胞培养诱导去分化。用维甲酸处理VSMC进行再分化。我们通过免疫组织化学和Western印迹分析平滑肌(SM)α-肌动蛋白和SM-肌球蛋白重链(MHC)来表征细胞的分化状态。去分化VSMC的功能性钙通道数明显减少，经维甲酸诱导分化后功能钙通道数明显增加。采用全细胞电压钳技术检测细胞内钙通道功能。Western印迹和二氢吡啶结合分析发现，钙通道α(1)亚基和β(2)亚基的表达与SMα-肌动蛋白和SM-MHC的表达直接相关。我们得出结论，L型钙通道α(1)亚单位的表达，从而是一个功能性的钙通道，与特殊的平滑肌细胞功能所需的SM特异性蛋白的表达高度协调。此外，我们的结果表明，L型钙通道是血管平滑肌细胞分化的一个新的标志。这些数据表明，分化过程中离子通道表达的调节可能对正常的平滑肌功能具有重要的生理意义，并可能影响VSMC在病理生理条件下的行为。
Despite intensive interest in understanding the differentiation of vascular smooth muscle cells (VSMC), no information is available about differential regulation of ion channels in these cells. Since expression of the L-type Ca2+ channel can be influenced by differentiation in other cell types, we tested the hypothesis that the L-ype (C class) channel is a specific differentiation marker of VSMC and that expression of these channels depends on the state of cell differentiation. We used rat aortic (A7r5) VSMC, which express functional L-type Ca2+ channels, and induced dedifferentiation by cell culture in different media. Treatment with retinoic acid was used to redifferentiate the VSMC. We characterized the differentiated state of the cells by using immunohistochemistry and Western blot analysis for smooth muscle (SM) alpha-actin and SM-myosin heavy chain (MHC). The number of functional Ca2+ channels was significantly decreased in dedifferentiated VSMC and increased upon differentiation with retinoic acid. Ca2+ channel function was assessed by whole-cell voltage clamp techniques. Using Western blot and dihydropyridine binding analysis, we found that the expression of the Ca2+ channel alpha(1) subunit, and to a lesser extent the beta(2) subunit, was directly correlated with the expression of SM alpha-actin and SM-MHC. We conclude that expression of L-type Ca2+ channel alpha(1) subunits, and thus a functional Ca2+ channel, is highly coordinated with expression of the SM-specific proteins required for specialized smooth muscle cell functions. Furthermore, our results demonstrate that the L-type Ca2+ channel is a novel marker for differentiation of VSMC. The data suggest that regulation of ion channel expression during differentiation may have physiological importance for normal smooth muscle function and may influence VSMC behavior under pathophysiological conditions.