PARP induced oxidative stress and mitochondrial failure

聚（ADP-核糖）聚合酶1（PARP 1）的激活可导致缺血和其他引起氧化应激的条件下的细胞死亡。PARP 1介导的细胞死亡与NAD+耗竭和ATP耗竭有关，但从PARP 1激活到细胞死亡的生化事件仍然不确定。本文提出的研究基于该实验室的最新发现，表明a）PARP 1激活导致细胞腺嘌呤核苷酸库的深度消耗; B）PARP 1激活引起的NAD+消耗导致葡萄糖利用受阻; c）PARP 1激活有助于氧化应激。重要的是，如果在PARP 1活化后的时间点防止PARP 1介导的细胞死亡，靶向逆转这些生化变化的干预是有效的，这是与缺血-再灌注和相关病症的治疗相关的方面。然而，这种体内治疗方法的障碍是血脑屏障通常阻碍腺嘌呤核苷酸和其他化合物进入脑实质。在这里，我们建议尝试几种方法， 在缺血再灌注模型中穿过BBB。我们还旨在进一步阐明PARP 1激活导致细胞死亡的机制，特别是PARP 1激活对氧化应激和线粒体代谢的影响。PARP 1 4-小鼠、SOD 2 +/小鼠和这些品系的杂交将用于阐明PARP 1激活后继发性氧化应激和内源性保护机制的影响。将使用细胞培养模型来充分表征PARAGUAY介导的细胞死亡的下游机制，并且将使用小鼠中风模型来证实体外发现，并测试在缺血后时期递送腺嘌呤核苷酸前体和线粒体底物穿过血液屏障的几种方法。

Activation of poly (ADP-ribose) polymerase 1 (PARP1) can lead to cell death during ischemia and other conditions that cause oxidative stress. PARP1 -mediated cell death is linked to NAD+ depletion and ATP depletion, but the biochemical events leading from PARP1 activation to cell death remain uncertain. The studies proposed here are based on recent findings in this laboratory showing that a) PARP1 activation leads to a profound depletion in cellular adenine nucleotide pool; b) NAD+ depletion caused by PARP1 activation leads to a block in glucose utilization; and c) PARP1 activation contributes to oxidative stress. Importantly, interventions that target reversal of these biochemical changes are effective if preventing PARP1 -mediated cell death at time points after PARP1 activation, an aspect with relevance to the treatment of ischemia-reperfusion and related disorders. An obstacle to this treatment approach in vivo, however, is that the blood-brain-barrier normally impedes access of adenine nucleotides and other compounds to the brain parenchyma. Here we propose to try several methods of crossing the BBB in a model of ischemia reperfusion. We also aim to further delineate the mechanisms by which PARP1 activation leads to cell death, in particular effects of PARP1 activation on oxidative stress and mitochondrial metabolism. PARP1 4- mice, SOD2 +/mice, and crosses of these strains will be used to elucidate the effects of secondary oxidative stress and endogenous protective mechanisms after PARP1 activation. Cell culture models will be used to fully characterize the downstream mechanisms of PARAGUAY -mediated cell death, and a mouse stroke model will be used to corroborate the in vitro findings and to test several approaches for delivering adenine nucleotide precursors and mitochondrial substrates across the blood-barrier in the post-ischemic period.