Thrombomodulin Is a Clock-controlled Gene in Vascular Endothelial Cells*
Thrombomodulin Is a Clock-controlled Gene in Vascular Endothelial Cells*
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DOI：
10.1074/jbc.m705692200
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发表时间：
2007-11
影响因子：
4.8
通讯作者：
Norihiko Takeda;K. Maemura;S. Horie;K. Oishi;Y. Imai;T. Harada;Tetsuya Saito;T. Shiga;E. Amiya;I. Manabe;N. Ishida;R. Nagai
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文献类型：
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作者：
Norihiko Takeda;K. Maemura;S. Horie;K. Oishi;Y. Imai;T. Harada;Tetsuya Saito;T. Shiga;E. Amiya;I. Manabe;N. Ishida;R. Nagai
心血管疾病与昼夜节律密切相关，昼夜节律受体内生物钟机制的控制。虽然生物钟不仅存在于下丘脑中，而且存在于每个外周组织中，但外周时钟的生物学相关性仍有待阐明。在这项研究中，我们利用微阵列技术在血管内皮细胞中寻找时钟控制基因。Clock/BMAL2共上调了229个基因的表达。在我们鉴定的基因中，我们进一步研究了血栓调节蛋白(TM)基因，因为TM是一种完整的膜糖蛋白，主要表达于血管内皮细胞，在血管内凝血的调节中发挥重要作用。在小鼠肺和心脏中，TM基因和蛋白的表达呈现明显的昼夜振荡。利用TM启动子进行的报告分析、凝胶位移分析和染色质免疫沉淀分析表明，Clock和BMAL2的异源二聚体直接与TM启动子的E-box结合，导致TM启动子的反式激活。事实上，在Clock突变小鼠中，TM基因表达的振荡被取消，这表明TM的表达在体内受到Clock基因的调节。最后，时间取食限制改变了TM基因表达的昼夜振荡阶段，表明TM基因的表达受外周时钟系统的调控。综上所述，这些数据表明，血管内皮细胞的外周时钟调节TM基因的表达，TM表达的振荡可能有助于心血管事件的昼夜变化。
Cardiovascular diseases are closely related to circadian rhythm, which is under the control of an internal biological clock mechanism. Although a biological clock exists not only in the hypothalamus but also in each peripheral tissue, the biological relevance of the peripheral clock remains to be elucidated. In this study we searched for clock-controlled genes in vascular endothelial cells using microarray technology. The expression of a total of 229 genes was up-regulated by CLOCK/BMAL2. Among the genes that we identified, we examined the thrombomodulin (TM) gene further, because TM is an integral membrane glycoprotein that is expressed primarily in vascular endothelial cells and plays a major role in the regulation of intravascular coagulation. TM mRNA and protein expression showed a clear circadian oscillation in the mouse lung and heart. Reporter analyses, gel shift assays, and chromatin immunoprecipitation analyses using the TM promoter revealed that a heterodimer of CLOCK and BMAL2 binds directly to the E-box of the TM promoter, resulting in TM promoter transactivation. Indeed, the oscillation of TM gene expression was abolished in clock mutant mice, suggesting that TM expression is regulated by the clock gene in vivo. Finally, the phase of circadian oscillation of TM mRNA expression was altered by temporal feeding restriction, suggesting TM gene expression is regulated by the peripheral clock system. In conclusion, these data suggest that the peripheral clock in vascular endothelial cells regulates TM gene expression and that the oscillation of TM expression may contribute to the circadian variation of cardiovascular events.