Insulin increases the functional activity of the renal NaCl cotransporter.
Insulin increases the functional activity of the renal NaCl cotransporter.
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DOI：
10.1097/hjh.0b013e32835bbb83
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发表时间：
2013-02
影响因子：
4.9
通讯作者：
Gamba G
中科院分区：
文献类型：
--
作者：
Chávez-Canales M;Arroyo JP;Ko B;Vázquez N;Bautista R;Castañeda-Bueno M;Bobadilla NA;Hoover RS;Gamba G
胰岛素被认为可以增加远端肾单位的肾盐重吸收，高胰岛素状态已被证明与肾脏NaCl共转运蛋白NCC的表达增加有关。然而，胰岛素对NCC功能活性的影响尚未见报道。利用非洲爪蟾卵母细胞的异种表达系统、小鼠远端卷曲细胞系、mDCT15细胞、内源性表达NCC以及离体肾灌注技术，我们评估了胰岛素对NCC活性和磷酸化的影响。分析了所涉及的信号通路。在非洲爪蟾卵母细胞中，胰岛素增加了NCC的活性，并使其苏氨酸残基58磷酸化。在mDCT15细胞中也观察到胰岛素对NCC的激活。此外，在体外灌注技术下，胰岛素增加了肾脏NCC的磷酸化。在卵母细胞和mDCT15细胞中，胰岛素对NCC的作用可以用PI3K、mTORC2和AKT1激酶抑制剂来阻止，但不能用MAP或mTORC1激酶抑制剂来阻止，这表明PI3K-mTORC2-AKT1是细胞内通路所必需的。此外，胰岛素对NCC的激活不受野生型或突变型WNK1、WNK4或SGK1的影响，但在野生型或显性阴性、催化失活的WNK3存在时不再观察到这种情况，这表明该激酶参与了这一过程。胰岛素诱导NCC的活化和磷酸化。这种作用可能在与高胰岛素状态相关的动脉高血压（如肥胖、代谢综合征或2型糖尿病）中发挥重要作用。
Insulin is recognized to increase renal salt reabsorption in the distal nephron and hyperinsulinemic states have been shown to be associated with increased expression of the renal NaCl cotransporter, NCC. However, the effect of insulin on NCC functional activity has not been reported. Using a heterologous expression system of Xenopus laevis oocytes, a mouse distal convoluted cell line, mDCT15 cells, endogenously expressing NCC, and an ex vivo kidney perfusion technique, we assessed the effect of insulin on the activity and phosphorylation of NCC. The signaling pathway involved was analyzed. In Xenopus oocytes insulin increases the activity of NCC together with its phosphorylation at threonine residue 58. Activation of NCC by insulin was also observed in mDCT15 cells. Additionally, insulin increased the NCC phosphorylation in kidney under the ex vivo perfusion technique. In oocytes and mDCT15 cells, insulin effect on NCC was prevented with inhibitors of PI3K, mTORC2, and AKT1 kinases, but not by inhibitors of MAP or mTORC1 kinases, suggesting that PI3K-mTORC2-AKT1 is the intracellular pathway required. Additionally, activation of NCC by insulin was not affected by wild type or mutant versions of WNK1, WNK4, or SGK1, but it was no longer observed in the presence of wild type or the dominant negative, catalytically inactive WNK3, implicating this kinase in the process. Insulin induces activation and phosphorylation of NCC. This effect could play an important role in arterial hypertension associated with hyperinsulinemic states, such as obesity, metabolic syndrome, or type 2 diabetes mellitus.