Opii Wycliffe O, Nukala Vidya N, Sultana Rukhsana, Pandya Jignesh D, Day Kristen M, Merchant Michael L, Klein Jon B, Sullivan Patrick G, Butterfield D Allan
Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, USA.
J Neurotrauma. 2007 May;24(5):772-89. doi: 10.1089/neu.2006.0229.
Experimental traumatic brain injury (TBI) results in a significant loss of cortical tissue at the site of injury, and in the ensuing hours and days a secondary injury exacerbates this primary injury, resulting in significant neurological dysfunction. The mechanism of the secondary injury is not well understood, but evidence implicates a critical role for mitochondria in this cascade. This mitochondrial dysfunction is believed to involve excitotoxicity, disruption of Ca(2+) homeostasis, production of reactive oxygen species (ROS), ATP depletion, oxidative damage of mitochondrial proteins, and an overall breakdown of mitochondrial bioenergetics. Although oxidative damage occurs following TBI, the identities of proteins undergoing oxidative modification after TBI have not been investigated. In the present study, we utilized the 3-h post-injury controlled cortical impact model of experimental TBI in 20 young adult male Sprague-Dawley rats, coupled with proteomics to identify specific mitochondrial fraction proteins from the cortex and hippocampus that were oxidatively modified after TBI. We identified, from the cortex, pyruvate dehydrogenase, voltage-dependent anion channel, fumarate hydratase 1, ATP synthase, and prohibitin. From the hippocampus, we identified cytochrome C oxidase Va, isovaleryl coenzyme A dehydrogenase, enolase-1, and glyceraldehyde-3-phosphate dehydrogenase as proteins that had undergone oxidative modification following TBI. In addition, we have also shown that, following TBI, there is a reduction in the activities of pyruvate dehydrogenase (PDH), complex I, and complex IV. These findings demonstrate that, following TBI, several proteins involved in mitochondrial bioenergetics are highly oxidatively modified, which may possibly underlie the massive breakdown of mitochondrial energetics and eventual cell death known to occur in this model. The identification of these proteins provides new insights into the mechanisms that take place following TBI and may provide avenues for possible therapeutic interventions after TBI.
实验性创伤性脑损伤（TBI）会导致损伤部位的皮质组织大量丧失，在随后的数小时和数天内，继发性损伤会加剧这种原发性损伤，导致严重的神经功能障碍。继发性损伤的机制尚未完全明确，但有证据表明线粒体在这一过程中起关键作用。这种线粒体功能障碍被认为涉及兴奋性毒性、钙（Ca2+）稳态破坏、活性氧（ROS）生成、ATP耗竭、线粒体蛋白质的氧化损伤以及线粒体生物能量学的整体崩溃。尽管TBI后会发生氧化损伤，但TBI后发生氧化修饰的蛋白质的具体身份尚未得到研究。在本研究中，我们在20只年轻成年雄性Sprague-Dawley大鼠中采用损伤后3小时的实验性TBI控制性皮质撞击模型，并结合蛋白质组学来鉴定皮质和海马体中经TBI氧化修饰的特定线粒体部分蛋白质。我们从皮质中鉴定出丙酮酸脱氢酶、电压依赖性阴离子通道、延胡索酸水合酶1、ATP合酶和抑制素。从海马体中，我们鉴定出细胞色素C氧化酶Va、异戊酰辅酶A脱氢酶、烯醇化酶-1和3-磷酸甘油醛脱氢酶为TBI后发生氧化修饰的蛋白质。此外，我们还表明，TBI后丙酮酸脱氢酶（PDH）、复合体I和复合体IV的活性降低。这些发现表明，TBI后，几种参与线粒体生物能量学的蛋白质发生了高度氧化修饰，这可能是该模型中已知的线粒体能量学大规模崩溃和最终细胞死亡的潜在原因。这些蛋白质的鉴定为TBI后发生的机制提供了新的见解，并可能为TBI后的可能治疗干预提供途径。
