Department of Anesthesiology, University of Rochester Medical Center, Rochester, New York 14642, USA.
J Biol Chem. 2012 Jan 27;287(5):3573-80. doi: 10.1074/jbc.M111.298406. Epub 2011 Dec 9.
Electrophilic nitrated lipids (nitroalkenes) are emerging as an important class of protective cardiovascular signaling molecules. Although species such as nitro-linoleate (LNO(2)) and nitro-oleate can confer acute protection against cardiac ischemic injury, their mechanism of action is unclear. Mild uncoupling of mitochondria is known to be cardioprotective, and adenine nucleotide translocase 1 (ANT1) is a key mediator of mitochondrial uncoupling. ANT1 also contains redox-sensitive cysteines that may be targets for modification by nitroalkenes. Therefore, in this study we tested the hypothesis that nitroalkenes directly modify ANT1 and that nitroalkene-mediated cardioprotection requires ANT1. Using biotin-tagged LNO(2) infused into intact perfused hearts, we obtained mass spectrometric (MALDI-TOF-TOF) evidence for direct modification (nitroalkylation) of ANT1 on cysteine 57. Furthermore, in a cell model of ischemia-reperfusion injury, siRNA knockdown of ANT1 inhibited the cardioprotective effect of LNO(2). Although the molecular mechanism linking ANT1-Cys(57) nitroalkylation and uncoupling is not yet known, these data suggest that ANT1-mediated uncoupling may be a mechanism for nitroalkene-induced cardioprotection.
亲电硝化脂质（亚硝烯）作为一类重要的保护心血管信号分子而出现。虽然像亚硝酰基亚麻酸（LNO(2)）和亚硝酰基油酸这样的物质可以提供急性心脏缺血性损伤的保护，但它们的作用机制尚不清楚。已知轻度解偶联线粒体具有心脏保护作用，而腺嘌呤核苷酸转位酶 1（ANT1）是线粒体解偶联的关键介质。ANT1 还含有氧化还原敏感的半胱氨酸，可能是亚硝烯修饰的靶标。因此，在这项研究中，我们假设亚硝烯直接修饰 ANT1，并且亚硝烯介导的心脏保护作用需要 ANT1。我们使用生物素标记的 LNO(2)注入完整的灌注心脏，通过基质辅助激光解吸/电离飞行时间/飞行时间（MALDI-TOF-TOF）质谱获得了 ANT1 上半胱氨酸 57 直接修饰（亚硝烷基化）的证据。此外，在缺血再灌注损伤的细胞模型中，ANT1 的 siRNA 敲低抑制了 LNO(2)的心脏保护作用。虽然将 ANT1-Cys(57)亚硝烷基化与解偶联联系起来的分子机制尚不清楚，但这些数据表明 ANT1 介导的解偶联可能是亚硝烯诱导心脏保护的机制。
