Oxidative Lipidomics in Pediatric Traumatic Brain Injury

氧化脂质组学在小儿创伤性脑损伤中的应用

基本信息

批准号：
8771719
负责人：
Hülya Bayir
金额：
$ 33.69万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-07-01 至 2019-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8771719
关键词：
Acute Address Affinity Anabolism Antioxidants Apoptosis Apoptotic Binding Brain Brain Injuries Cardiolipins Cause of Death Cessation of life Child Childhood Injury Chronic Clinical Trials Complex Computer Simulation Data Electrons Enzymes Event Exhibits Figs - dietary Free Radical Scavengers Free Radicals Funding Genetic Hospitalization Hydrogen Peroxide In Vitro Injury Inner mitochondrial membrane Lead Link Manganese Mechanics Methodology Mitochondria Molecular Analysis Morbidity - disease rate Nature Neurological outcome Neuronal Injury Neurons Nucleoside-Diphosphate Kinase Organic Chemicals Outcome Outer Mitochondrial Membrane Oxidation-Reduction Oxidative Stress Pathway interactions Pattern Peptides Peroxidases Phospholipids Porphyrins Production Proteins Protocols documentation Rattus Reactive Oxygen Species Reporting Role Source Staging Stretching Superoxide Dismutase Superoxides Technology Testing Therapeutic Therapeutic Uses Translations Trauma Traumatic Brain Injury base biochemical model cardiolipin synthase catalyst chemical synthesis cognitive function controlled cortical impact cytochrome c design drug discovery glutathione peroxidase improved in vivo inhibitor/antagonist liquid chromatography mass spectrometry mortality neuron apoptosis neuronal survival novel novel therapeutics oxidation pediatric traumatic brain injury peroxidation phospholipid scramblase postnatal prevent public health relevance research study response small molecule standard care therapeutic target translocase

项目摘要

DESCRIPTION (provided by applicant): Each year in the US, severe TBI in children results in <7400 deaths and 60 000 hospitalizations. Fifty percent of surviving children with severe TBI have poor neurological outcome at six months. Severe TBI in children is thus a critical problem in desperate need of impactful therapies. Free radicals and oxidative stress have been accepted as universal pathogenic mechanisms of TBI prompting the therapeutic use of antioxidants. Invariably, the clinical trials of non-specific free radical scavengers/antioxidants failed. Unless the true sources and mechanisms of TBI redox imbalance are identified, the use of sacrificial antioxidants and free radical scavengers will fail. Thus, a paradigm-shifting approach is required. During prior funding period, we discovered that selective peroxidation of a mitochondria-specific phospholipid, cardiolipin (CL), occurs in severe pediatric TBI and represents a required mitochondrial stage of neuronal apoptosis. We further identified cytochrome c (cyt c) as a catalyst of CL peroxidation occurring via the formation of cyt c/CL complexes with peroxidase activity triggered by H2O2 . Thus cyt c/CL redox interactions and CL peroxidation represent a missing causal link between known reactive oxygen species production and mitochondrial pro-apoptotic responses. Importantly, our preliminary data show that a mitochondria-targeted small molecule inhibitor of CL peroxidation suppressed TBI-induced apoptosis in vivo and preserved cognitive function in postnatal day (PND) 17 rats. In normal mitochondria, CL and cyt c are physically separated: CL is confined almost exclusively to the inner mitochondrial membrane. Binding of cyt c with CL depends on the collapse of CL asymmetry and translocation of CL to the outer mitochondrial membrane. While the mechanisms of collapse of CL asymmetry are poorly understood, preliminary data show that two candidate proteins - nucleoside diphosphate kinase (NDPK-D) and phospholipid scramblase-3 (PLSCR3) -facilitate CL translocation. Our hypothesis is that collapse of CL asymmetry and formation of cyt c/CL peroxidase complexes trigger - in the presence of H2O2 - CL peroxidation and release of proapoptotic factors from mitochondria in immature brain after TBI. Thus, maintaining CL asymmetry and suppression of peroxidase activity will improve neuronal survival and outcome after TBI. To test our hypothesis and its successful translation, we will employ multi-disciplinary approach combining in vitro (mechanical stretch injury of neurons) and in vivo (controlled cortical impact in PND17 rats) TBI models, biochemical (oxidative lipidomics) and biophysical (new protocols for assessment of asymmetry and externalization of CL in mitochondria) methodology, genetic and pharmacological approaches as well as computational modeling and organic chemical synthesis. These studies will provide important mechanistic information on the role of CL asymmetry and oxidation in neuronal apoptosis after TBI. The ability to selectively modulate CL oxidation, a critical early event in apoptosis, could lead to targeted therapies for TBI and ultimately improve outcome for children after brain injury.

描述（由申请人提供）：在美国，每年，严重的儿童创伤性脑损伤会导致<7400 人死亡和 60 000 人住院治疗。 50% 的患有严重 TBI 的幸存儿童在六个月时神经系统结果不佳。因此，儿童严重创伤性脑损伤是一个迫切需要有效治疗的关键问题。自由基和氧化应激已被认为是 TBI 的普遍致病机制，促使抗氧化剂的治疗使用。非特异性自由基清除剂/抗氧化剂的临床试验总是失败。除非一旦确定了 TBI 氧化还原失衡的真正来源和机制，使用牺牲性抗氧化剂和自由基清除剂就会失败。因此，需要一种范式转变的方法。在之前的资助期间，我们发现线粒体特异性磷脂、心磷脂 (CL) 的选择性过氧化发生在严重的儿科 TBI 中，并且代表了神经元凋亡所需的线粒体阶段。我们进一步确定细胞色素 c (cyt c) 是 CL 过氧化反应的催化剂，通过形成 cyt c/CL 复合物，并具有由 H2O2 触发的过氧化物酶活性。因此，细胞色素 c/CL 氧化还原相互作用和 CL 过氧化代表了已知的活性氧产生和线粒体促凋亡反应之间缺失的因果关系。重要的是，我们的初步数据表明，一种针对线粒体的 CL 过氧化小分子抑制剂可抑制 TBI 诱导的体内细胞凋亡，并保留出生后 (PND) 17 只大鼠的认知功能。在正常线粒体中，CL 和细胞色素 c 在物理上是分开的：CL 几乎完全局限于线粒体内膜。细胞色素 c 与 CL 的结合取决于 CL 不对称性的崩溃和 CL 易位至线粒体外膜。虽然我们对 CL 不对称性崩溃的机制知之甚少，但初步数据表明，两种候选蛋白 - 核苷二磷酸激酶 (NDPK-D) 和磷脂扰乱酶 3 (PLSCR3) - 促进 CL 易位。我们的假设是，在 TBI 后未成熟大脑中，在 H2O2 存在的情况下，CL 不对称性的崩溃和细胞色素 c/CL 过氧化物酶复合物的形成会引发 CL 过氧化和线粒体中促凋亡因子的释放。因此，维持 CL 不对称性和抑制过氧化物酶活性将改善 TBI 后神经元的存活和预后。为了检验我们的假设及其成功转化，我们将采用多学科方法，结合体外（神经元的机械拉伸损伤）和体内（PND17 大鼠的受控皮质影响）TBI 模型、生物化学（氧化脂质组学）和生物物理（新方案）用于评估线粒体中 CL 的不对称性和外化）方法、遗传和药理学方法以及计算模型和有机化学合成。这些研究将为 TBI 后 CL 不对称性和氧化在神经元凋亡中的作用提供重要的机制信息。选择性调节CL氧化（细胞凋亡中的一个关键早期事件）的能力可能会导致TBI的靶向治疗，并最终改善脑损伤后儿童的预后。