Tankyrase-mediated β-catenin activity regulates vasopressin-induced AQP2 expression in kidney collecting duct mpkCCDc14 cells
Tankyrase-mediated β-catenin activity regulates vasopressin-induced AQP2 expression in kidney collecting duct mpkCCDc14 cells
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DOI：
10.1152/ajprenal.00052.2014
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发表时间：
2015-03-01
影响因子：
4.2
通讯作者：
Kwon, Tae-Hwan
中科院分区：
文献类型：
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作者：
Jung, Hyun Jun;Kim, Sang-Yeob;Kwon, Tae-Hwan
水通道蛋白2（AQP 2）介导精氨酸加压素（AVP）诱导的肾脏集合管水重吸收。AVP主要通过G（s）alpha/cAMP/PKA信号通路调节AQP 2的表达。端锚聚合酶是聚（ADP-核糖）聚合酶家族的成员，已知其介导Wnt/β-连环蛋白信号传导诱导的基因表达。我们研究了端锚聚合酶是否在AVP诱导的AQP 2调节中通过G蛋白-α（G α）的ADP-核糖基化和/或β-连环蛋白介导的AQP 2转录发挥作用。RT-PCR和免疫印迹分析显示端锚聚合酶在小鼠肾脏和小鼠集合管mpkCCDc 14细胞中的mRNA和蛋白表达。在通过XAV 939处理或小干扰（si）RNA敲低抑制端锚聚合酶的情况下，dDAVP诱导的AQP 2上调在mpkCCDc 14细胞中减弱。然而，荧光共振能量转移图像分析显示，XAV 939处理不影响dDAVP或毛喉素诱导的PKA活化。端锚聚合酶的抑制降低了dDAVP诱导的β-连环蛋白（S552）磷酸化和磷酸-β-连环蛋白的核转位。siRNA介导的β-连环蛋白敲低降低了毛喉素诱导的AQP 2转录和dDAVP诱导的AQP 2表达。此外，磷酸肌醇3-激酶/Akt的抑制，这与β-连环蛋白的核转位减少，减少dDAVP诱导的AQP 2上调，进一步表明β-连环蛋白介导AQP 2的表达。总之，端锚聚合酶在AVP诱导的AQP 2调节中起作用，这可能是通过β-连环蛋白介导的AQP 2转录，而不是G α的ADP-核糖基化。这些结果为加压素介导的尿液浓度和体内水分代谢的稳态提供了新的见解。
Aquaporin-2 (AQP2) mediates arginine vasopressin (AVP)-induced water reabsorption in the kidney collecting duct. AVP regulates AQP2 expression primarily via G(s)alpha/cAMP/PKA signaling. Tankyrase, a member of the poly(ADP-ribose) polymerase family, is known to mediate Wnt/beta-catenin signaling-induced gene expression. We examined whether tankyrase plays a role in AVP-induced AQP2 regulation via ADP-ribosylation of G protein-alpha (G alpha) and/or beta-catenin-mediated transcription of AQP2. RT-PCR and immunoblotting analysis revealed the mRNA and protein expression of tankyrase in mouse kidney and mouse collecting duct mpkCCDc14 cells. dDAVP-induced AQP2 upregulation was attenuated in mpkCCDc14 cells under the tankyrase inhibition by XAV939 treatment or small interfering (si) RNA knockdown. Fluorescence resonance energy transfer image analysis, however, revealed that XAV939 treatment did not affect dDAVP-or forskolin-induced PKA activation. Inhibition of tankyrase decreased dDAVP-induced phosphorylation of beta-catenin (S552) and nuclear translocation of phospho-beta-catenin. siRNA-mediated knockdown of beta-catenin decreased forskolin-induced AQP2 transcription and dDAVP-induced AQP2 expression. Moreover, inhibition of phosphoinositide 3-kinase/Akt, which was associated with decreased nuclear translocation of beta-catenin, diminished dDAVP-induced AQP2 upregulation, further indicating that beta-catenin mediates AQP2 expression. Taken together, tankyrase plays a role in AVP-induced AQP2 regulation, which is likely via beta-catenin-mediated transcription of AQP2, but not ADP-ribosylation of G alpha. The results provide novel insights into vasopressin-mediated urine concentration and homeostasis of body water metabolism.