Weisová Petronela, Anilkumar Ujval, Ryan Caitriona, Concannon Caoimhín G, Prehn Jochen H M, Ward Manus W
Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
Biochim Biophys Acta. 2012 May;1817(5):744-53. doi: 10.1016/j.bbabio.2012.01.016. Epub 2012 Feb 7.
The preconditioning response conferred by a mild uncoupling of the mitochondrial membrane potential (Δψ(m)) has been attributed to altered reactive oxygen species (ROS) production and mitochondrial Ca(2+) uptake within the cells. Here we have explored if altered cellular energetics in response to a mild mitochondrial uncoupling stimulus may also contribute to the protection. The addition of 100 nM FCCP for 30 min to cerebellar granule neurons (CGNs) induced a transient depolarization of the Δψ(m), that was sufficient to significantly reduce CGN vulnerability to the excitotoxic stimulus, glutamate. On investigation, the mild mitochondrial 'uncoupling' stimulus resulted in a significant increase in the plasma membrane levels of the glucose transporter isoform 3, with a hyperpolarisation of Δψ(m) and increased cellular ATP levels also evident following the washout of FCCP. Furthermore, the phosphorylation state of AMP-activated protein kinase (AMPK) (Thr 172) was increased within 5 min of the uncoupling stimulus and elevated up to 1h after washout. Significantly, the physiological changes and protection evident after the mild uncoupling stimulus were lost in CGNs when AMPK activity was inhibited. This study identifies an additional mechanism through which protection is mediated upon mild mitochondrial uncoupling: it implicates increased AMPK signalling and an adaptive shift in energy metabolism as mediators of the preconditioning response associated with FCCP-induced mild mitochondrial uncoupling.
线粒体膜电位（Δψ(m)）轻度解偶联所赋予的预处理反应，被认为与细胞内活性氧（ROS）生成的改变以及线粒体Ca(2+)摄取有关。在此，我们探讨了响应轻度线粒体解偶联刺激时细胞能量代谢的改变是否也有助于这种保护作用。向小脑颗粒神经元（CGNs）中添加100 nM FCCP 30分钟，可诱导Δψ(m)出现短暂去极化，这足以显著降低CGNs对兴奋性毒性刺激物谷氨酸的易感性。经研究发现，轻度线粒体“解偶联”刺激导致葡萄糖转运蛋白异构体3的质膜水平显著增加，在洗去FCCP后，Δψ(m)出现超极化，细胞ATP水平也明显升高。此外，在解偶联刺激5分钟内，AMP活化蛋白激酶（AMPK）（Thr 172）的磷酸化状态增加，并在洗去后持续升高达1小时。重要的是，当AMPK活性被抑制时，CGNs中轻度解偶联刺激后明显的生理变化和保护作用消失。本研究确定了轻度线粒体解偶联介导保护作用的另一种机制：它表明AMPK信号增强以及能量代谢的适应性转变是与FCCP诱导的轻度线粒体解偶联相关的预处理反应的介质。
