Feedback inhibition of CREB signaling by p38 MAPK contributes to the negative regulation of steroidogenesis.
Feedback inhibition of CREB signaling by p38 MAPK contributes to the negative regulation of steroidogenesis.
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p38 MAPK 对 CREB 信号传导的反馈抑制有助于类固醇生成的负调节
DOI：
10.1186/s12958-017-0239-4
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发表时间：
2017-03-16
期刊：
影响因子：
--
通讯作者：
Hu Z
中科院分区：
文献类型：
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作者：
Li J;Zhou Q;Ma Z;Wang M;Shen WJ;Azhar S;Guo Z;Hu Z
甾体生成是一个复杂的、多步骤的生物过程，在这个过程中，胆固醇前体以组织特异性和热带激素依赖性的方式转化为类固醇。鉴于类固醇的形成是通过多种组织特异性酶的协调作用实现的，因此在此过程中会产生许多类固醇中间体/代谢物。类固醇产物和主要的脂蛋白胆固醇供体高密度脂蛋白3 （hHDL3）都有可能通过增加氧化应激/活性氧（ROS）的产生来负性调节类固醇生成。在本研究中，我们检测了孕烯醇酮、22(R)-羟基胆固醇[22(R)-二醇]或hHDL3对类固醇生成小鼠模型、Y1-BS1肾上腺皮质肿瘤细胞的影响，对ROS生成、p38 MAPK和cAMP反应元件结合蛋白（CREB）的磷酸化状态、CREB转录活性和StAR、CPY11A1/P450scc、抗氧化酶、超氧化物歧化酶[Cu、ZnSOD （SOD1）、MnSOD (SOD2)] mRNA表达的影响。过氧化氢酶（CAT）和谷胱甘肽过氧化物酶1 （GPX1）。我们还通过HPLC-MS / ms检测了p38 MAPK抑制剂处理Y1细胞后的类固醇产物，H2O2处理Y1细胞后，p38 MAPK和CREB蛋白的磷酸化均显著增强。同样，用孕烯醇酮、22(R)二醇或hHDL3处理细胞，用氧化敏感荧光探针2 ',7 ' -二氯荧光素二醋酸酯（DCFH-DA）测量，ROS产量增加。在相同的实验条件下，用这些药物处理细胞也增加了p38 MAPK和CREB的磷酸化。然而，CREB磷酸化的增加与其转录活性的降低有关。孕烯醇酮、22(R)-二醇和hHDL3对CREB磷酸化的刺激作用被一种特异性的p38 MAPK抑制剂SB203580消除。孕烯醇酮和22(R)二醇上调SOD1、SOD2和GPX1的mRNA表达，下调StAR和CYP11A1的mRNA表达，而hHDL3不上调。p38抑制剂SB203580可增加HDL3、22(R)-二醇或孕烯醇酮处理细胞的类固醇生成。我们的数据表明，氧胆固醇和类固醇中间体和产物通过抑制CREB转录活性来诱导ROS/p38 MAPK介导的反馈抑制途径。
Steroidogenesis is a complex, multi-steps biological process in which, cholesterol precursor is converted to steroids in a tissue specific and tropic hormone dependent manner. Given that steroidogenesis is achieved by coordinated functioning of multiple tissue specific enzymes, many steroids intermediates/metabolites are generated during this process. Both the steroid products as well as major lipoprotein cholesterol donor, high-density lipoprotein 3 (hHDL3) have the potential to negatively regulate steroidogenesis via increased oxidative stress/reactive oxygen species (ROS) generation. In the current study, we examined the effects of treatment of a mouse model of steroidogenesis, Y1-BS1 adrenocortical tumor cells with pregnenolone, 22(R)-Hydroxycholesterol [22(R)-diol] or hHDL3 on ROS production, phosphorylation status of p38 MAPK and cAMP response element-binding protein (CREB), CREB transcriptional activity and mRNA expression of StAR, CPY11A1/P450scc and antioxidant enzymes, superoxide dismutases [Cu,ZnSOD (SOD1), MnSOD (SOD2)], catalase (CAT) and glutathione peroxidase 1 (GPX1). We also detected the steroid product in p38 MAPK inhibitor treated Y1 cells by HPLC-MS / MS. Treatment of Y1 cells with H2O2 greatly enhanced the phosphorylation of both p38 MAPK and CREB protein. Likewise, treatment of cells with pregnenolone, 22(R) diol or hHDL3 increased ROS production measured with the oxidation-sensitive fluorescent probe 2′,7′-Dichlorofluorescin diacetate (DCFH-DA). Under identical experimental conditions, treatment of cells with these agents also increased the phosphorylation of p38 MAPK and CREB. This increased CREB phosphorylation however, was associated with its decreased transcriptional activity. The stimulatory effects of pregnenolone, 22(R)-diol and hHDL3 on CREB phosphorylation was abolished by a specific p38 MAPK inhibitor, SB203580. Pregnenolone, and 22(R) diol but not hHDL3 upregulated the mRNA expression of SOD1, SOD2 and GPX1, while down-regulated the mRNA levels of StAR and CYP11A1. The p38 inhibitor SB203580 could increase the steroid production in HDL3, 22(R)-diol or pregnenolone treated cells. Our data demonstrate induction of a ROS/p38 MAPK -mediated feedback inhibitory pathway by oxy-cholesterol and steroid intermediates and products attenuates steroidogenesis via inhibition of CREB transcriptional activity.