The role of mitochondrial uncoupling proteins in regulation of reactive oxygen species

线粒体呼吸过程中产生的活性氧(ROS)是细胞氧化损伤的主要原因，可能是神经退行性疾病和衰老的基础。它们的产量对线粒体的质子动力非常敏感，解偶联可能会减少。反过来，假设ROS影响UCP，增加(I)UCP质子传输速率和(Ii)蛋白质丰度。为了证明这两个假设，我们使用RT-PCR和共聚焦显微镜测量了(I)通过平面双层膜中重组的纯化蛋白的质子电流和(Ii)神经元细胞中的mRNA和UCP水平。在不同蛋白质表达水平的细胞中，通过使用荧光染料估计ROS数量和线粒体潜力来评估UCP对氧化损伤的保护作用。为了揭示解偶联和氧化损伤保护之间的功能联系，我们研究了具有不同功能的UCPs(UCP1，UCP2，UCP4)。区分ROS介导的UCP激活和上调，以及深入了解UCP对ROS的调控，有望为合理的药物设计提供基础，因此具有重要的临床意义。

Reactive oxygen species (ROS) produced during mitochondrial respiration are a major cause of the cellular oxidative damage that may underlie neurodegenerative diseases and ageing. Their production is very sensitive to the mitochondrial proton-motive force and may be decreased by uncoupling. In turn, ROS are hypothesized to affect UCP, increasing (i) UCP proton transport rate and (ii) protein abundance. To prove both hypotheses, we measure (i) proton currents through the purified protein reconstituted in planar bilayer membranes and (ii) mRNA and UCP levels in neuronal cells, using RT PCR and confocal microscopy. UCP protection against oxidative damage is evaluated by estimation of ROS amount and mitochondrial potential using fluorescent dyes in cells with different expression levels of protein. To reveal a functional link between uncoupling and protection against oxidative damage, UCPs with various putative functions (UCP1, UCP2, UCP4) are investigated. Differentiation between ROS-mediated UCP activation and upregulation as well as insight into ROS regulation by UCP are expected to provide the basis for a rational drug design, and have, thus, important clinical implications.