Selenium deficiency-induced thioredoxin suppression and thioredoxin knock down disbalanced insulin responsiveness in chicken cardiomyocytes through PI3K/Akt pathway inhibition
Selenium deficiency-induced thioredoxin suppression and thioredoxin knock down disbalanced insulin responsiveness in chicken cardiomyocytes through PI3K/Akt pathway inhibition
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缺硒诱导的硫氧还蛋白抑制以及硫氧还蛋白通过抑制 PI3K/Akt 通路降低鸡心肌细胞胰岛素反应失衡
DOI：
10.1016/j.cellsig.2017.07.012
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发表时间：
2017
影响因子：
4.8
通讯作者：
Zhang Ziwei
中科院分区：
文献类型：
--
作者：
Yang Jie;Hamid Sattar;Cai Jingzeng;Liu Qi;Xu Shiwen;Zhang Ziwei
硫氧还蛋白(TXN)系统是细胞内最重要的抗氧化防御机制，由TXN、硫氧还蛋白还原酶(TR)和烟酰胺腺嘌呤二核苷酸磷酸(NADPH)组成。TXN系统的紊乱可能通过氧化应激诱导影响细胞的存活。胰岛素的代谢活性在通过糖代谢来满足心脏稳定和持久的需求方面起着重要作用。然而，有关TXN及其系统在胰岛素调节心脏能量代谢中的作用的报道较少。因此，为了研究血栓素N在心肌代谢中的作用，我们建立了体内低硒鸡模型(0.033 mg/kg)和体外研究血栓素N抑制心肌细胞培养模型。采用实时定量聚合酶链式反应和免疫印迹技术。缺硒可抑制心肌组织中TXN和tR的表达。在两种模型中，ROS水平的显著增加标志着氧化应激的开始。TXN抑制模型和TXN下调模型心肌细胞的胰岛素样生长因子(IGF1、IGF2)、IGF结合蛋白(IGFBP2、IGFBP4)、胰岛素受体(IR)、胰岛素受体底物(IRS1、IRS2)和葡萄糖转运蛋白(GLUT1、GLUT3、GLUT8)的表达水平显著降低(P<0.05)，而TXN下调心肌细胞IGFBP3的表达水平升高。此外，与各自的对照组相比，缺硒的TXN耗竭组织和TXN缺失的心肌细胞PI3K、AKT、P-PI3K的mRNA和蛋白水平均受到抑制，Fox、P-Fox JNK基因的表达也受到抑制。结合体外和体内实验，我们证明TXN基因抑制可以通过抑制PI3K-Akt通路导致胰岛素调节的心脏能量代谢紊乱，增加胰岛素抵抗。因此，我们认为TXN系统失活可以通过抑制IRS/PI3K/Akt通路和JNK、Fox的表达来改变细胞的胰岛素反应。提示TXN系统可氧化还原调节心脏内胰岛素依赖型葡萄糖代谢，对细胞活力至关重要。此外，IGFBP3的表达增加表明，它可能是TXN缺陷细胞中潜在的胰岛素代谢活性的负调控因子。
Thioredoxin (Txn) system is the most crucial antioxidant defense mechanism in cell consisting of Txn, thioredoxin reductase (TR) and Nicotinamide Adenine Dinucleotide Phosphate (NADPH). Perturbations in Txn system may compromise cell survival through oxidative stress induction. Metabolic activity of insulin plays important roles in fulfilling the stable and persistent demands of heart through glucose metabolism. However, the roles of Txn and Txn system in insulin modulated cardiac energy metabolism have been less reported. Therefore, to investigate the role of Txn in myocardial metabolism, we developed a Se-deficient chicken model (0.033 mg/kg) for in-vivo and Txn knock down cardiomyocytes culture model (siRNA) for in-vitro studies. Quantitative real time PCR and western blotting was performed. Se deficiency suppressed Txn and TR in cardiac tissues. Significant increases in ROS (P < 0.05) levels signify the onset of oxidative stress and in both models. Se deficiency-induced Txn suppression model and Txn knock down cardiomyocytes models significantly decreased (P < 0.05), the mRNA and protein levels of insulin-like growth factors (IGF1, IGF2), IGF-binding proteins (IGFBP2, IGFBP4), insulin receptor (IR), insulin receptor substrates (IRS1, IRS2), and glucose transporters (GLUT1, GLUT3, GLUT8), however, IGFBP3 expression increased in Txn knock down cardiomyocytes. In addition, in contrast to their respective controls, Se deficiency-induced Txn depleted tissues and Txn deleted cardiomyocytes showed suppression in mRNA and protein levels of PI3K, AKT, P-PI3K, and repression in FOX, P-FOX JNK genes. Combing the in vitro and in vivo experiments, we demonstrate that Txn gene suppression can cause dysfunction of insulin-modulated cardiac energy metabolism and increase insulin resistance through PI3K-Akt pathway inhibition. Herein, we conclude that inactivation of Txn system can alter cellular insulin response through IRS/PI3K/Akt pathway repression and JNK and FOX expression. These findings point out that Txn system can redox regulate the insulin dependent glucose metabolism in heart and is essential for cell vitality. Moreover, the increased expression of IGFBP3 indicates that it can be a potential negative modulator of metabolic activity of insulin in Txn deficient cells.