Molecular Pathways of Programmed Cell Death And Viral Cytopathicity

程序性细胞死亡和病毒细胞病变的分子途径

• 批准号: 8745344
• 负责人: michael j lenardo
• 金额: $ 27.93万
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8745344
• 关键词: Acquired Immunodeficiency Syndrome; Antioxidants; Apoptosis; Apoptotic; Autophagocytosis; BNIP3L gene; Brain; Cardiac; Cardiac Myocytes; Cell Death; Cell Surface Receptors; Cell Survival; Cell physiology; Cells; Cellular Morphology; Cellular Stress; Cessation of life; Complex; Cytoplasmic Organelle; Cytoplasmic Protein; DICER1 gene; Data; Diagnosis; Digestion; Disease; Drosophila genus; Embryo; Energy-Generating Resources; Equilibrium; Exhibits; Family; Fibroblasts; Genes; Genetic; Genetic Programming; Goals; HIV; Heart; Host Defense; Human; Immune; Immune response; Infectious Agent; Injury; Investigation; Ischemia; Knockout Mice; Lead; Lymphocyte; Lysosomes; Mediating; Mediator of activation protein; Membrane; MicroRNAs; Mitochondria; Mitochondrial Proteins; Modeling; Molecular; Morbidity - disease rate; Morphology; Mus; Mutation; Myocardial Infarction; Necrosis; Nerve; Neurodegenerative Disorders; Organ; Outcome; PTEN-induced putative kinase; Parkinson Disease; Pathogenesis; Pathway interactions; Pattern; Peptide Hydrolases; Phosphoglycerate Mutase; Phosphotransferases; Physiological; Play; Process; Protein Serine/Threonine Phosphatase; Proteins; RIPK3 gene; Receptor Signaling; Recruitment Activity; Regulation; Regulator Genes; Reperfusion Injury; Reperfusion Therapy; Reporting; Role; Severe Acute Respiratory Syndrome; Severities; Signal Pathway; Stroke; TNFRSF1A gene; TNFRSF6 gene; Tumor Necrosis Factor Receptor; Vesicle; Viral; Virus; Virus Diseases; Wild Type Mouse; Work; Yeasts; cancer cell; caspase-8; cell growth regulation; cell injury; cell type; improved; in vivo; insight; interest; member; mortality; nuclear factor 1; nuclease; oxidative damage; palliative; paralogous gene; phosphoglycerate; preference; presenilin; programs; receptor; response; rhomboid; transcription factor; ubiquitin-protein ligase

Internal death programs play significant roles in many diseases. Pathogenic effects can result from inefficient cell death or from inappropriate or excessive death such as that caused by the human immunodeficiency virus (HIV) during AIDS or the SAR-CoV virus during SARS. In this project, we are taking a multifaceted approach to studying molecular mechanisms of both apoptotic and nonapoptotic death programs in lymphocytes as well as other cell types. A major focus of our investigations are death-inducing cell surface receptors in the tumor necrosis factor receptor (TNFR) superfamily such as TNFR1 and CD95/Fas/APO-1. Both receptors play an important role in stimulating both apoptotic and nonapoptotic death of cells principally in immune processes. Little is known about how these alternative death pathways are entrained to receptor signaling. Interestingly, both receptors can have effects beside death such as the induction of transcription factors. We are trying to understand how these receptors stimulate the intracellular machinery that causes cell death in preference to other cellular outcomes. We have discovered that inhibition of caspase-8 in non-lymphoid cells can lead to another form of cell death exhibiting particular cytoplasmic double membrane structures called autophagy. Autophagy is an evolutionarily conserved process from humans to yeast by which cytoplasmic proteins and organelles are catabolized but very little was known about results at the end of autophagy when cells were selecting between autophagic cell death and survival. Mitochondria have a primary physiological role in producing ATP as an energy source, but also regulate cell death. In response to cellular stress, dysfunctional mitochondria produce ROS and other pro-death mediators to initiate programmed cell death pathways, like apoptosis or necropotosis. Mitophagy, a selective form of autophagy, can target dysfunctional mitochondria for lysosomal degradation and protect cells from oxidative damage. This is beneficial for the survival of terminally differentiated cells, like nerve and heart muscle cells. Several regulators of mitophagy, including PINK1, Nix (BNIP3L), and PARKIN have been identified. Mutations or deletions of those genes have been related with a variety of diseases, including ischemia injury in myocardial infarction and stroke, as well as neurodegenerative disease. Hence, understanding the detailed mechanism of mitophagy remains an important goal for improving the diagnosis and treatment of diseases involving mitochondria. Two autosomal recessive Parkinsons disease genes, PINK1 (PTEN induced putative kinase 1) and PARKIN, regulate mitophagic clearance of dysfunctional mitochondria. In healthy cells, PINK1 is constitutively degraded by mitochondrial proteases, such as mitochondria inner membrane protease Presenilin Associated, Rhomboid-Like (PARL) protein. Membrane depolarization of dysfunctional mitochondria inhibits PINK1 degradation, causing it to accumulate and promote mitophagy via recruitment of another familial Parkinson's protein, the E3 ubiquitin ligase PARKIN. However, the detailed mechanism of PINK1 degradation and stabilization remains unclear. We have studyPGAM5, paralog member 5 of a family of highly conserved phosphoglycerate mutases, a 32-kDa mitochondrial protein that apparently lacks phosphotransfer function on phosphoglycerates, but retains activity as a serine/threonine protein phosphatase that regulates the ASK1 kinase. The functions of PGAM5 are complex since it also serves as an anti-oxidant regulator in the Kelch ECH associating protein 1-nuclear factor-E2-related factor 2 (KEAP1-NRF2) signaling pathway (19, 20). Recently, PGAM5 was found as a downstream mitochondrial target of RIP3 in the necrosis pathway in cancer cells, by recruiting the RIP1-RIP3-MLKL necrosis "attack" complex to mitochondria (3, 21). Interestingly, PGAM5 has also been reported as a genetic suppressor of PINK1 in Drosophila (22), as well as a substrate of PARL (23). Thus, it is important to establish the in vivo role of PGAM5 involving mitochondria. using a new strain of knockout mice, we found that PGAM5 is critical for PINK1 stabilization on damaged mitochondria to initiate mitophagy since loss of PGAM5 totally disables PINK1 stabilization. Cells deficient with PGAM5 showed elevated ROS originated from mitochondria, and exacerbated cell necrosis compared to control wild type cells. In stroke and cardiac ischemic-reperfusion injury models, PGAM5-deficient mice showed significantly increased severity of injuries in the brain and heart compared to wild-type mice, indicating that PGAM5 protects against ischemia-reperfusion-induced necrosis. Taken together, our data suggest that PGAM5 promotes PINK1-mediated mitophagy, which could be cytoprotective in ischemic injuries. Moreover, PGAM5 also provides a functional linkage between malfunction of mitophagy and the pathogenesis of necrosis.

内部死亡计划在许多疾病中扮演着重要的角色。致病效应可由低效细胞死亡或不适当或过度死亡引起，如艾滋病期间的人类免疫缺陷病毒(HIV)或SARS期间的SAR-CoV病毒造成的死亡。在这个项目中，我们正在采取多方面的方法来研究淋巴细胞和其他细胞类型中凋亡和非凋亡死亡程序的分子机制。我们研究的一个主要焦点是肿瘤坏死因子受体(TNFR)超家族中的死亡诱导细胞表面受体，如TNFR1和CD95/Fas/APO-1。这两种受体都在刺激细胞的凋亡性和非凋亡性死亡方面发挥重要作用，主要是在免疫过程中。关于这些替代死亡途径如何与受体信号联系在一起，我们知之甚少。有趣的是，这两种受体都可以起到除死亡以外的作用，比如诱导转录因子。我们正在试图了解这些受体是如何刺激细胞内机制的，这种机制导致细胞死亡，而不是其他细胞结果。我们已经发现，在非淋巴样细胞中抑制caspase-8可以导致另一种形式的细胞死亡，表现出特殊的细胞质双膜结构，称为自噬。自噬是从人类到酵母的一个进化保守的过程，细胞质蛋白和细胞器被分解，但在自噬结束时，当细胞在自噬细胞死亡和存活之间进行选择时，人们对结果知之甚少。线粒体作为一种能量来源，在产生三磷酸腺苷方面起着主要的生理作用，但也调节细胞死亡。作为对细胞应激的反应，功能失调的线粒体产生ROS和其他促死亡介质来启动程序性细胞死亡途径，如细胞凋亡或死亡。有丝分裂是一种选择性的自噬形式，可以针对功能障碍的线粒体进行溶酶体降解，并保护细胞免受氧化损伤。这有利于终末分化细胞的存活，如神经和心肌细胞。已经确定了几种丝裂原吞噬调节因子，包括PINK1、NIX(BNIP3L)和Parkin。这些基因的突变或缺失与多种疾病有关，包括心肌梗死和中风中的缺血性损伤，以及神经退行性疾病。因此，了解线粒体吞噬的详细机制仍然是提高线粒体疾病诊断和治疗的重要目标。两个常染色体隐性遗传性帕金森氏病基因，PINK1(PTEN诱导的推定激酶1)和Parkin，调节功能失调的线粒体的有丝分裂清除。在健康细胞中，PINK1被线粒体蛋白降解，如线粒体内膜蛋白、早老素相关蛋白、类菱形蛋白等。功能障碍的线粒体膜去极化抑制PINK1的降解，使其积聚，并通过募集另一种家族性帕金森氏症蛋白，E3泛素连接酶Parkin来促进有丝分裂。然而，PINK1降解和稳定的详细机制仍不清楚。我们研究了PGAM5，一个高度保守的磷酸甘油酸变构酶家族的Paralog成员5，一个32 kDa的线粒体蛋白，显然缺乏对磷酸甘油的磷酸转移功能，但作为调节ASK1激酶的丝氨酸/苏氨酸蛋白磷酸酶保持活性。PGAM5的功能是复杂的，因为它也是Kelch ECH相关蛋白1-核因子-E2相关因子2(Keap1-NRF2)信号通路(19，20)中的抗氧化调节因子。最近，通过募集RIP1-RIP3-MLKL坏死复合体对线粒体(3，21)的攻击，PGAM5被发现是RIP3在肿瘤细胞坏死途径中的下游线粒体靶点。有趣的是，在果蝇中，PGAM5也被报道为PINK1的遗传抑制因子(22)，以及PARL的底物(23)。因此，确定PGAM5在体内涉及线粒体的作用是很重要的。使用一种新的基因敲除小鼠，我们发现PGAM5对于PINK1在受损线粒体上稳定启动有丝分裂至关重要，因为PGAM5的丢失完全使PINK1失去稳定。与对照野生型细胞相比，缺失PGAM5的细胞显示线粒体来源的ROS升高，细胞坏死加剧。在中风和心脏缺血-再灌注损伤模型中，与野生型小鼠相比，PGAM5缺陷小鼠的脑和心脏损伤严重程度显著增加，表明PGAM5对缺血-再灌注诱导的坏死具有保护作用。综上所述，我们的数据表明，PGAM5促进了PINK1介导的有丝分裂，这可能在缺血损伤中起到细胞保护作用。此外，PGAM5还提供了吞噬核分裂功能障碍与坏死发病机制之间的功能联系。