Chronic nicotine exposure augments renal oxidative stress and injury through transcriptional activation of p66shc
Chronic nicotine exposure augments renal oxidative stress and injury through transcriptional activation of p66shc
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DOI：
10.1093/ndt/gfs596
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发表时间：
2013-06-01
影响因子：
6.1
通讯作者：
Juncos, Luis A.
中科院分区：
文献类型：
--
作者：
Arany, Istvan;Clark, Jeb;Juncos, Luis A.
...慢性尼古丁暴露增加缺血-再灌注诱导的AKI依赖性丝氨酸36磷酸化（S36 A）和缺血-再灌注诱导的AKI依赖性肾脏p66 shc表达。慢性尼古丁（Ch-NIC）暴露可加重缺血/再灌注（I/R）诱导的氧化应激和急性肾损伤（阿基），以及培养的肾近端小管细胞（RPTC）中活性氧（ROS）的线粒体产生。由于Ser 36磷酸化的p66 shc调节线粒体ROS的产生和RPTC的损伤，我们推测Ch-NIC通过增加应激诱导的p66 shc磷酸化而加重阿基。我们首先在体内测试Ch-NIC是否增加I/R-AKI诱导的p66 shc表达和磷酸化。然后，我们研究了是否敲低p66 shc，或削弱其Ser 36磷酸化或与细胞色素c的结合，改变Ch-NIC对氧化应激（H2 O2）诱导的ROS产生，线粒体去极化和体外RPTCs损伤的影响，我们发现Ch-NIC增加了对照和缺血肾中p66 shc的表达，但只增加了肾I/R后其Ser 36磷酸化。通过S36 A突变（而不是磷酸模拟S36 D突变）敲低p66 shc或损害其Ser 36残基的磷酸化，减弱了RPTC中Ch-NIC H2 O2依赖性ROS的产生、线粒体去极化和损伤。此外，Ch-NIC H2 O2依赖性p66 shc与线粒体细胞色素c的结合被p66 shc的S36 A突变减弱，并且损害细胞色素c结合（通过W134 F突变）废除了ROS产生、线粒体去极化和损伤，而异位过表达p66 shc（其模拟Ch-NIC处理）增强了氧化损伤。我们确定Ch-NIC通过p53和表观遗传修饰（启动子低甲基化）刺激p66 shc启动子。Ch-NIC通过增加p66 shc的表达和随后的氧化应激依赖性Ser 36磷酸化来减轻氧化应激依赖性急性肾损伤。因此，靶向该途径可能在预防/改善烟草相关的肾损伤方面具有治疗相关性。
...chronic nicotine exposure increased the ischemia-reperfusion-induced AKI-dependent serine 36 phosphorylation (S36A) and ischemia-reperfusion-induced AKI-dependent renal expression of p66shc...Chronic nicotine (Ch-NIC) exposure exacerbates ischemia/reperfusion (I/R)-induced oxidative stress and acute kidney injury (AKI), and mitochondrial production of reactive oxygen species (ROS) in cultured renal proximal tubule cells (RPTCs). Because Ser36-phosphorylated p66shc modulates mitochondrial ROS production and injury of RPTCs, we hypothesized that Ch-NIC exacerbates AKI by increasing stress-induced phosphorylation of p66shc.We first tested whether Ch-NIC augments I/R-AKI-induced expression and phosphorylation of p66shc in vivo. We then examined whether knocking down p66shc, or impairing its Ser36 phosphorylation or binding to cytochrome c, alters the effects of Ch-NIC on oxidative stress (H2O2)-induced production of ROS, mitochondrial depolarization and injury in RPTCs in vitro.We found that Ch-NIC increased the expression of p66shc in the control and ischemic kidneys, but only increased its Ser36 phosphorylation after renal I/R. Knocking down p66shc or impairing phosphorylation of its Ser36 residue, via the S36A mutation (but not the phosphomimetic S36D mutation), blunted Ch-NIC H2O2-dependent ROS production, mitochondrial depolarization and injury in RPTCs. Additionally, Ch-NIC H2O2-dependent binding of p66shc to mitochondrial cytochrome c was attenuated by S36A mutation of p66shc, and impairing cytochrome c binding (via W134F mutation) abolished ROS production, mitochondrial depolarization and injury, while ectopic overexpression of p66shc (which mimics Ch-NIC treatment) augmented oxidant injury. We determined that Ch-NIC stimulates the p66shc promoter through p53- and epigenetic modification (promoter hypomethylation).Ch-NIC worsens oxidative stress-dependent acute renal injury by increasing expression and consequent oxidative stress-dependent Ser36 phosphorylation of p66shc. Thus, targeting this pathway may have therapeutic relevance in preventing/ameliorating tobacco-related kidney injury.