Rescue and Role of Complex I in myocardial ischemic injury

描述(由申请人提供)：在我们对由促凋亡的Bcl-2家族成员的线粒体膜通透性介导的凋亡的理解方面已经取得了相当大的进展。然而，在心肌缺血/再灌注损伤的背景下，细胞死亡的一个重要机制是线粒体通透性转换孔(MPTP)介导的灾难性线粒体肿胀。在我们对HL-1心肌细胞模拟缺血再灌注的研究中，Bax和Bid募集到线粒体是在MPTP之后发生的，并依赖于MPTP。我们建议在活体内确定是否存在这种情况。在缺血/再灌流中，线粒体磷脂酶(IPLA2)被激活并释放花生四烯酸，花生四烯酸通过激活MPTP而促进超氧化物的产生和细胞的死亡。我们建议确定线粒体中花生四烯酸的相关靶点。由于最近的研究表明，在VDAC基因缺失的小鼠、ANT基因缺失的小鼠和亲环素D基因缺失的小鼠中，MPTP仍然可以打开，因此对包括外膜VDAC、内膜ANT和亲环素D(基质/内膜)的MPTP的既定观点提出了质疑。与传统的MPTP观点平行积累的证据表明，氧化磷酸化复合体I是MPTP的关键成分。我们现在提出来自亲环素D过度表达的小鼠的新证据，进一步支持复合体I在MPTP中的作用。我们假设花生四烯酸和亲环素D与复合体I相互作用来调节孔道的开放。公共卫生相关性：了解心脏病发作期间和发作后发生的分子过程可能会导致缺血性心脏病和心力衰竭的新疗法。我们将探讨心肌缺血和再灌流中线粒体灾难性肿胀的基础。我们将确定导致线粒体损伤的脂肪酸，以及参与其中的线粒体蛋白。我们将开发一种新的蛋白质疗法来治疗心脏病发作后的心脏损伤，它将绕过受损的线粒体酶复合体来恢复功能。

DESCRIPTION (provided by applicant): Considerable progress has been made in our understanding of apoptosis mediated by permeabilization of the mitochondrial membrane by pro-apoptotic Bcl-2 family members. However, in the context of myocardial ischemia/reperfusion injury, a significant mechanism of cell death is catastrophic mitochondrial swelling mediated by the mitochondrial permeability transition pore (MPTP). In our studies of HL-1 myocytes subjected to simulated ischemia and reperfusion, Bax and Bid recruitment to mitochondria occurs after and is dependent upon MPTP. We propose to determine whether this is the case in vivo. In ischemia/reperfusion, a mitochondrial phospholipase (iPLA2) is activated and liberates arachidonic acid, which contributes to superoxide production and cell death through activation of the MPTP. We propose to identify the relevant target of arachidonic acid in the mitochondrion. The established view of the MPTP comprising VDAC in the outer membrane, ANT in the inner membrane, and cyclophilin D (matrix/inner membrane) has been questioned in light of recent studies showing that the MPTP can still open in VDAC-null mice, ANT-null mice, and cyclophilin D-null mice, although the threshold is altered. Evidence that has accumulated in parallel to the traditional view of the MPTP has implicated oxidative phosphorylation Complex I as a key element in the MPTP. We now present new evidence derived from cyclophilin D-overexpressing mice that further supports a role for Complex I in the MPTP. We hypothesize that arachidonic acid and cyclophilin D interact with Complex I to regulate pore opening. PUBLIC HEALTH RELEVANCE: Understanding the molecular processes that take place during and after a heart attack may lead to new therapies for ischemic heart disease and heart failure. We will explore the basis for catastrophic mitochondrial swelling in myocardial ischemia and reperfusion. We will identify the fatty acids that contribute to mitochondrial damage, as well as the mitochondrial proteins that are involved. We will develop a novel protein therapy for treatment of heart damage after a heart attack that will bypass the damaged mitochondrial enzyme complex to restore function.