Mechanisms of angiotensin II stimulation of NCC are time-dependent in mDCT15 cells.
Mechanisms of angiotensin II stimulation of NCC are time-dependent in mDCT15 cells.
复制标题
在 mDCT15 细胞中，血管紧张素 II 刺激 NCC 的机制具有时间依赖性。
DOI：
10.1152/ajprenal.00465.2014
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Hoover,RobertS
中科院分区：
文献类型：
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作者：
Ko,Benjamin;Mistry,Abinash;Hanson,Lauren;Mallick,Rickta;Hoover,RobertS
血管紧张素II（ANG II）急性和慢性增加噻嗪敏感性氯化钠协同转运蛋白（NCC）的活性。ANG II被认为是将WNK 4从NCC的抑制剂转变为NCC的激活剂的开关，并且ANG II对NCC的作用似乎需要WNK 4。慢性时，ANG II刺激NCC导致总NCC和磷酸化NCC增加，但NCC磷酸化在急性ANG II作用中的作用尚不清楚。在这里，使用具有强大的天然NCC活性的哺乳动物细胞模型，我们证实了ANG II在WNK 4调节中发挥的作用，并阐明了Ste20相关的脯氨酸富含丙氨酸激酶（SPAK）诱导的NCC磷酸化在ANG II作用中的作用。ANG II对NCC具有双相作用，在10− 11 M ANG II的生理范围内，NCC活性达到峰值。这种效果是明显的，早在15分钟，并保持持续到120分钟。这些变化与NCC表面蛋白表达的显着增加。WNK 4表达的敲低显著减弱了ANG II的作用。在早期时间点，SPAK敲除不影响ANG II作用相应地，NCC磷酸化在15或30分钟时没有增加，但在60分钟时显著增加。因此，我们得出结论，在ANG II增加的几分钟内，NCC以磷酸化非依赖性但WNK 4依赖性的方式快速运输到细胞表面。然后，60分钟后，ANG II诱导NCC的SPAK依赖性磷酸化。
Angiotensin II (ANG II) increases thiazide-sensitive sodium-chloride cotransporter (NCC) activity both acutely and chronically. ANG II has been implicated as a switch that turns WNK4 from an inhibitor of NCC into an activator of NCC, and ANG II's effect on NCC appears to require WNK4. Chronically, ANG II stimulation of NCC results in an increase in total and phosphorylated NCC, but the role of NCC phosphorylation in acute ANG II actions is unclear. Here, using a mammalian cell model with robust native NCC activity, we corroborate the role that ANG II plays in WNK4 regulation and clarify the role of Ste20-related proline alanine-rich kinase (SPAK)-induced NCC phosphorylation in ANG II action. ANG II was noted to have a biphasic effect on NCC, with a peak increase in NCC activity in the physiologic range of 10−11M ANG II. This effect was apparent as early as 15 min and remained sustained through 120 min. These changes correlated with significant increases in NCC surface protein expression. Knockdown of WNK4 expression sharply attenuated the effect of ANG II. SPAK knockdown did not affect ANG II action at early time points (15 and 30 min), but it did attenuate the response at 60 min. Correspondingly, NCC phosphorylation did not increase at 15 or 30 min, but increased significantly at 60 min. We therefore conclude that within minutes of an increase in ANG II, NCC is rapidly trafficked to the cell surface in a phosphorylation-independent but WNK4-dependent manner. Then, after 60 min, ANG II induces SPAK-dependent phosphorylation of NCC.