DDAH1 deficiency promotes intracellular oxidative stress and cell apoptosis via a miR-21-dependent pathway in mouse embryonic fibroblasts.
DDAH1 deficiency promotes intracellular oxidative stress and cell apoptosis via a miR-21-dependent pathway in mouse embryonic fibroblasts.
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DOI：
10.1016/j.freeradbiomed.2016.01.015
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发表时间：
2016-03
影响因子：
7.4
通讯作者：
Chenyang Zhao;Tianhe Li;Bingxing Han;W. Yue;Linlin Shi;Hongyun Wang;Yuting Guo;Zhongbing Lu
中科院分区：
文献类型：
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作者：
Chenyang Zhao;Tianhe Li;Bingxing Han;W. Yue;Linlin Shi;Hongyun Wang;Yuting Guo;Zhongbing Lu
不对称二甲基精氨酸（ADMA）是一种内源性一氧化氮合酶（NOS）抑制剂，可被二甲基精氨酸二甲氨基水解酶1（DDAH 1）降解。新出现的证据表明，血浆ADMA蓄积、DDAH 1活性/表达降低和microRNA-21（miR-21）上调与疾病病理学有关，但其机制在很大程度上仍未知。在本研究中，我们使用野生型（WT）和DDAH 1敲除（KO）永生化小鼠胚胎成纤维细胞（MEF）评估了ADMA-DDAH 1-miR-21通路在细胞氧化还原状态和凋亡调节中的潜在作用。DDAH 1缺陷显著增加ADMA水平，增强细胞氧化应激，并使细胞更容易受到叔丁基过氧化氢（tBHP）或A23187诱导的凋亡。然而，外源性ADMA（1-80 μM）处理WT MEFs 24 h或延长时间（10 μM，10代）对细胞内活性氧（ROS）和凋亡敏感性没有明显影响。有趣的是，在DDAH 1 −/−MEFs中，miR-21的表达显著增加了4倍，DDAH 1缺陷对miR-21的诱导依赖于氧化应激和NF-κB激活。PD 404182对DDAH 1活性的抑制也增加了miR-21的表达。此外，在DDAH 1 −/−MEFs中用慢病毒载体抑制miR-21可显著上调SOD 2表达，并减弱tBHP或A23187诱导的氧化应激和凋亡。综上所述，我们的研究结果表明，DDAH 1不仅作为一种酶降解ADMA，但也通过miR-21依赖性途径控制细胞的氧化应激和凋亡。
Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase (NOS) inhibitor, is degraded by dimethylarginine dimethylaminohydrolase 1 (DDAH1). Emerging evidence suggests that plasma ADMA accumulation, DDAH1 activity/expression reduction, and microRNA-21 (miR-21) upregulation are linked to disease pathology, but the mechanisms remain largely unknown. In the present study, we assessed the potential role of the ADMA–DDAH1–miR-21 pathway in the regulation of the cellular redox state and apoptosis using wild-type (WT) and DDAH1-knockout (KO) immortalized mouse embryonic fibroblasts (MEFs). DDAH1 deficiency significantly increased ADMA levels, enhanced cellular oxidative stress, and rendered cells more vulnerable to apoptosis induced bytert-butyl hydroperoxide (tBHP) or A23187. However, treatment with exogenous ADMA (1–80 μM) for 24 h or for a prolonged period (10 μM, 10 passages) in WT MEFs had no marked effect on intracellular reactive oxygen species (ROS) and apoptosis sensitivity. Interestingly, miR-21 expression was significantly increased, by 4 fold, in DDAH1−/−MEFs, and the induction of miR-21 by DDAH1 deficiency was dependent on oxidative stress and NF-κB activation. Inhibition of DDAH1 activity by PD 404182 also increased miR-21 expression. Furthermore, inhibition of miR-21 with a lentiviral vector in DDAH1−/−MEFs significantly upregulated SOD2 expression and the attenuated oxidative stress and apoptosis induced by tBHP or A23187. Taken together, our results suggest that DDAH1 not only acts as an enzyme degrading ADMA but also controls cellular oxidative stress and apoptosis via a miR-21-dependent pathway.