Regulation of ENaC-mediated alveolar fluid clearance by insulin via PI3K/Akt pathway in LPS-induced acute lung injury.
Regulation of ENaC-mediated alveolar fluid clearance by insulin via PI3K/Akt pathway in LPS-induced acute lung injury.
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DOI：
10.1186/1465-9921-13-29
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发表时间：
2012-03-30
影响因子：
5.8
通讯作者：
Wang DX
中科院分区：
文献类型：
--
作者：
Deng W;Li CY;Tong J;Zhang W;Wang DX
刺激上皮钠通道（ENaC）增加Na+转运，这是肺泡液体清除（AFC）的驱动力，以保持肺泡空间不含对急性肺损伤（ALI）有益的水肿液体。胰岛素对ENaC的调控主要通过PI 3 K信号通路，但该信号通路在ALI中调控AFC和ENaC的机制尚不清楚。本研究旨在探讨胰岛素对急性肺损伤（ALI）时AFC的影响，阐明胰岛素在体内外调控ENaC表达的途径。用微量渗透泵持续注射外源性胰岛素和渥曼青霉素建立SD大鼠无高血糖的急性肺损伤模型。在ALI后8小时分离肺用于测量支气管肺泡灌洗液（BALF）、肺总含水量（TLW）和AFC。在胰岛素处理2小时之前，将肺泡上皮II型细胞与LY 294002、Akt抑制剂和SGK 1抑制剂预孵育30分钟。采用免疫细胞化学、逆转录聚合酶链反应（RT-PCR）和Western blotting检测α-、β-和γ-ENaC的表达。在体内，胰岛素可降低LPS诱导的ALI大鼠TLW，增加AFC，增加α-、β-、γ-ENaC表达和磷酸化Akt水平，减轻肺损伤，提高存活率，其作用可被wortmannin阻断。阿米洛利，钠通道抑制剂，显着降低胰岛素诱导的AFC增加。在体外实验中，胰岛素可增加α-、β-和γ-ENaC的表达以及磷酸化Akt的水平，但LY 294002和Akt抑制剂可分别显著抑制胰岛素诱导的ENaC表达和磷酸化Akt水平的增加。免疫沉淀研究表明，胰岛素通过PI 3 K/Akt途径降低Nedd 4 -2与ENaC的结合水平。我们的研究表明，胰岛素通过抑制Nedd 4 -2增加依赖于PI 3 K/Akt通路的ENaC的表达来减轻肺水肿并增强AFC。
Stimulation of epithelial sodium channel (ENaC) increases Na+ transport, a driving force of alveolar fluid clearance (AFC) to keep alveolar spaces free of edema fluid that is beneficial for acute lung injury (ALI). It is well recognized that regulation of ENaC by insulin via PI3K pathway, but the mechanism of this signaling pathway to regulate AFC and ENaC in ALI remains unclear. The aim of this study was to investigate the effect of insulin on AFC in ALI and clarify the pathway in which insulin regulates the expression of ENaC in vitro and in vivo. A model of ALI (LPS at a dose of 5.0 mg/kg) with non-hyperglycemia was established in Sprague-Dawley rats receiving continuous exogenous insulin by micro-osmotic pumps and wortmannin. The lungs were isolated for measurement of bronchoalveolar lavage fluid(BALF), total lung water content(TLW), and AFC after ALI for 8 hours. Alveolar epithelial type II cells were pre-incubated with LY294002, Akt inhibitor and SGK1 inhibitor 30 minutes before insulin treatment for 2 hours. The expressions of α-,β-, and γ-ENaC were detected by immunocytochemistry, reverse transcriptase polymerase chain reaction (RT-PCR) and western blotting. In vivo, insulin decreased TLW, enchanced AFC, increased the expressions of α-,β-, and γ-ENaC and the level of phosphorylated Akt, attenuated lung injury and improved the survival rate in LPS-induced ALI, the effects of which were blocked by wortmannin. Amiloride, a sodium channel inhibitor, significantly reduced insulin-induced increase in AFC. In vitro, insulin increased the expressions of α-,β-, and γ-ENaC as well as the level of phosphorylated Akt but LY294002 and Akt inhibitor significantly prevented insulin-induced increase in the expression of ENaC and the level of phosphorylated Akt respectively. Immunoprecipitation studies showed that levels of Nedd4-2 binding to ENaC were decreased by insulin via PI3K/Akt pathway. Our study demonstrated that insulin alleviated pulmonary edema and enhanced AFC by increasing the expression of ENaC that dependent upon PI3K/Akt pathway by inhibition of Nedd4-2.
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影响因子：
16.6
作者：
Boase, Natasha A.;Rychkov, Grigori Y.;Townley, Scott L.;Dinudom, Anuwat;Candi, Eleanora;Voss, Anne K.;Tsoutsman, Tatiana;Semsarian, Chris;Melino, Gerry;Koentgen, Frank;Cook, David I.;Kumar, Sharad
通讯作者：
Kumar, Sharad
DOI：
10.1152/ajplung.00373.2006
发表时间：
2007-09-01
影响因子：
4.9
作者：
Elias, Nael;Rafii, Bijan;O'Brodovich, Hugh
通讯作者：
O'Brodovich, Hugh
影响因子：
4.8
作者：
Jeschke, MG;Klein, D;Einspanier, R
通讯作者：
Einspanier, R
影响因子：
8.8
作者：
Abraham, E
通讯作者：
Abraham, E
影响因子：
4.6
作者：
Jiang, Lijun;Wang, Qiang;Wu, Song
通讯作者：
Wu, Song