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.

内部死亡程序在许多疾病中发挥着重要作用。 致病作用可能是由低效的细胞死亡或不适当或过度的死亡引起的，例如艾滋病期间的人类免疫缺陷病毒（HIV）或SARS期间的SAR-CoV病毒引起的死亡。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以及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) 超家族中诱导死亡的细胞表面受体，例如 TNFR1 和 CD95/Fas/APO-1。 两种受体主要在免疫过程中刺激细胞凋亡和非凋亡死亡中发挥重要作用。人们对这些替代性死亡途径如何被受体信号传导影响知之甚少。 有趣的是，这两种受体都可以产生除死亡之外的作用，例如诱导转录因子。我们试图了解这些受体如何刺激细胞内机制，从而导致细胞死亡而不是其他细胞结果。我们发现，在非淋巴细胞中抑制 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进化上保守的过程，细胞质蛋白和细胞器通过该过程被分解代谢，但当细胞在自噬细胞死亡和生存之间进行选择时，人们对自噬结束时的结果知之甚少。线粒体在产生 ATP 作为能源方面发挥着主要的生理作用，但也调节细胞死亡。为了应对细胞应激，功能失调的线粒体会产生 ROS 和其他促死亡介质，以启动程序性细胞死亡途径，如细胞凋亡或坏死性凋亡。线粒体自噬是自噬的一种选择性形式，可以针对功能失调的线粒体进行溶酶体降解，并保护细胞免受氧化损伤。这有利于神经细胞和心肌细胞等终末分化细胞的存活。已鉴定出多种线粒体自噬调节因子，包括 PINK1、Nix (BNIP3L) 和 PARKIN。这些基因的突变或缺失与多种疾病有关，包括心肌梗塞和中风的缺血性损伤，以及神经退行性疾病。因此，了解线粒体自噬的详细机制仍然是改善线粒体疾病诊断和治疗的重要目标。两个常染色体隐性帕金森病基因 PINK1（PTEN 诱导的推定激酶 1）和 PARKIN 调节功能失调的线粒体的线粒体自噬清除。在健康细胞中，PINK1 会被线粒体蛋白酶组成型降解，例如线粒体内膜蛋白酶早老素相关菱形样 (PARL) 蛋白。功能失调的线粒体的膜去极化会抑制 PINK1 降解，导致其积累并通过招募另一种家族性帕金森病蛋白 E3 泛素连接酶 PARKIN 来促进线粒体自噬。然而，PINK1 降解和稳定的详细机制仍不清楚。我们研究了 PGAM5，它是高度保守的磷酸甘油酸变位酶家族的旁系同源成员 5，它是一种 32-kDa 的线粒体蛋白，显然缺乏磷酸甘油酸的磷酸转移功能，但保留了作为调节 ASK1 激酶的丝氨酸/苏氨酸蛋白磷酸酶的活性。 PGAM5 的功能很复杂，因为它还在 Kelch ECH 相关蛋白 1-核因子-E2 相关因子 2 (KEAP1-NRF2) 信号通路中充当抗氧化调节剂 (19, 20)。最近，通过将 RIP1-RIP3-MLKL 坏死“攻击”复合物募集到线粒体，发现 PGAM5 是癌细胞坏死途径中 RIP3 的下游线粒体靶标 (3, 21)。 有趣的是，PGAM5 还被报道为果蝇中 PINK1 的基因抑制因子 (22)，以及 PARL 的底物 (23)。因此，确定 PGAM5 涉及线粒体的体内作用非常重要。使用一种新的基因敲除小鼠品系，我们发现 PGAM5 对于受损线粒体上的 PINK1 稳定以启动线粒体自噬至关重要，因为 PGAM5 的缺失会完全禁用 PINK1 的稳定。 与对照野生型细胞相比，缺乏 PGAM5 的细胞表现出源自线粒体的 ROS 升高，并且细胞坏死加剧。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 缺陷小鼠的大脑和心脏损伤严重程度显着增加，表明 PGAM5 可以防止缺血再灌注引起的坏死。综上所述，我们的数据表明 PGAM5 促进 PINK1 介导的线粒体自噬，这可能在缺血性损伤中具有细胞保护作用。此外，PGAM5 还提供了线粒体自噬功能障碍和坏死发病机制之间的功能联系。