Regulation of aquaporin 3 expression by magnesium ion.
Regulation of aquaporin 3 expression by magnesium ion.
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DOI：
10.1016/j.ejphar.2008.03.063
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发表时间：
2008-06
影响因子：
5
通讯作者：
Masasi Okahira;Masafumi Kubota;K. Iguchi;S. Usui;K. Hirano
中科院分区：
文献类型：
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作者：
Masasi Okahira;Masafumi Kubota;K. Iguchi;S. Usui;K. Hirano
为了理解镁制剂（氧化镁和硫酸镁作为抗酸剂的成分）在胃肠道中的作用，在Caco-2细胞中研究了镁离子对已知主要对水和甘油可渗透的水通道水通道蛋白3（AQP 3）的作用。实时荧光定量RT-PCR和Western blotting检测水通道蛋白3的mRNA和蛋白表达，发现经醋酸镁处理后，水通道蛋白3的mRNA和蛋白表达均显著增加。信号转导抑制剂MDL-12330 A、H-89、U 0126和Ro 31-8220显示抑制mRNA表达的增加。构建了水通道蛋白3基因5′侧翼区-1382 ~-12 bp的荧光素酶报告基因载体，用于报告基因检测。用乙酸镁处理后，转染子中的荧光素酶活性增加。序列缺失构建体揭示了负责镁离子介导的活化的两个区域，一个在bp-404和-190之间，另一个在bp-190和-82之间。位于bp -404和-190之间的cAMP反应元件结合蛋白（CREB）序列的siRNA抵消了镁离子介导的水通道蛋白3转录的激活。这些结果表明，信号转导，腺苷酸环化酶，蛋白激酶A（PKA），有丝分裂原激活的蛋白激酶1/2（MEK 1/2），和有丝分裂原和应激激活的蛋白激酶1（MSK 1），参与调节水通道蛋白3基因的转录信号通路和CREB是镁离子介导的水通道蛋白3基因表达的转录调节因子之一。
For understanding the actions of magnesium formulations, magnesium oxide and magnesium sulfate as a constituent of antacid, in the gastrointestinal tract, the effect of magnesium ion on the water channel aquaporin 3 (AQP3) known to be permeable mainly to water and glycerol was investigated in Caco-2 cells. The mRNA and protein of aquaporin 3 were detected by real-time RT-PCR and Western blotting, respectively, and found to increase significantly after treatment with magnesium acetate. Inhibitors for signal transducers, MDL-12330A, H-89, U0126, and Ro 31-8220, were shown to repress the increase in expression of the mRNA. A luciferase reporter vector containing bp -1382 to -12 of the 5′-flanking region of the aquaporin 3 gene was constructed for a reporter gene assay. The luciferase activity in transfectants increased on treatment with magnesium acetate. Serial deletion constructs revealed two regions responsible for the magnesium ion-mediated activation, one between bps -404 and -190, and the other between bps -190 and -82. siRNA for the cAMP response element-binding protein (CREB) sequence located between bp -404 and -190 counteracted the magnesium ion-mediated activation of aquaporin 3 transcription. These results suggest that signal transducers, adenylyl cyclase, protein kinase A (PKA), mitogen-activated protein kinase 1/2 (MEK1/2), and mitogen- and stress-activated protein kinase 1 (MSK1), were involved in the signaling pathway for regulating transcription of the aquaporin 3 gene and CREB is one of the transcriptional regulators for aquaporin 3 gene expression mediated by magnesium ion.