Cartin L, Lounsbury K M, Nelson M T
Department of Pharmacology, University of Vermont, Burlington, VT, USA.
Circ Res. 2000 Apr 14;86(7):760-7. doi: 10.1161/01.res.86.7.760.
Pathological changes of the vasculature are characterized by changes in Ca(2+) handling and alterations in gene expression. In neurons and other cell types, Ca(2+) often drives changes in gene expression. However, the relationship between Ca(2+) signaling and gene expression in vascular smooth muscle is not well understood. This study examines the ability of Ca(2+) influx through voltage-dependent, L-type Ca(2+) channels (VDCCs) and Ca(2+) release through ryanodine receptors (RyRs) to activate the transcription factor, cAMP-responsive element binding protein (CREB), and increase c-fos levels in intact cerebral arteries. Membrane depolarization increased the fraction of nuclei staining for phosphorylated CREB (P-CREB) and levels of c-fos mRNA in intact mouse cerebral arteries. Ryanodine, which inhibits RyRs, increased P-CREB staining and c-fos levels. Forskolin, an activator of adenylyl cyclase, and sodium nitroprusside, an NO donor, increased P-CREB and c-fos levels. Nisoldipine, an inhibitor of VDCCs, reversed the effects of depolarization and ryanodine on P-CREB and c-fos levels, but not the effects of forskolin or sodium nitroprusside. Inhibition of Ca(2+)/calmodulin-dependent protein kinase (CaM kinase) blocked increases in P-CREB and c-fos levels seen with membrane depolarization, suggesting that CaM kinase has an important role in the pathway leading from Ca(2+) influx to CREB-mediated changes in c-fos levels. Our data suggest that membrane depolarization increases Ca(2+) through activation of VDCCs, leading to increased P-CREB and c-fos, and that RyRs have a profound effect on this pathway by indirectly regulating Ca(2+) entry through VDCCs. These results provide the first evidence of Ca(2+) regulation of CREB and c-fos in arterial smooth muscle.
血管的病理变化以钙离子处理的改变和基因表达的变化为特征。在神经元和其他细胞类型中，细胞内钙离子浓度（Ca(2+)）常常驱动基因表达的变化。然而，钙离子信号与血管平滑肌中基因表达之间的关系尚未得到充分理解。本研究考察了通过电压依赖性L型钙离子通道（VDCCs）的钙离子内流以及通过兰尼碱受体（RyRs）的钙离子释放激活转录因子环磷酸腺苷反应元件结合蛋白（CREB）并增加完整脑动脉中c-fos水平的能力。膜去极化增加了完整小鼠脑动脉中磷酸化CREB（P-CREB）染色的细胞核比例以及c-fos mRNA水平。抑制RyRs的兰尼碱增加了P-CREB染色和c-fos水平。腺苷酸环化酶激活剂福斯高林以及一氧化氮供体硝普钠增加了P-CREB和c-fos水平。VDCCs抑制剂尼索地平逆转了去极化和兰尼碱对P-CREB和c-fos水平的影响，但没有逆转福斯高林或硝普钠的作用。抑制钙离子/钙调蛋白依赖性蛋白激酶（CaM激酶）可阻断膜去极化时观察到的P-CREB和c-fos水平的升高，这表明CaM激酶在从钙离子内流到CREB介导的c-fos水平变化的信号通路中起重要作用。我们的数据表明，膜去极化通过激活VDCCs增加细胞内钙离子浓度（Ca(2+)），导致P-CREB和c-fos增加，并且RyRs通过间接调节VDCCs的钙离子内流对该信号通路有深远影响。这些结果首次证明了钙离子对动脉平滑肌中CREB和c-fos的调节作用。
