PATHWAYS TO ROS INDUCED CELL DEATH

ROS 诱导细胞死亡的途径

• 批准号: 6548441
• 负责人: TERRENCE J. MONKS
• 金额: $ 33.24万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6548441
• 关键词: DNA damage; DNA replication; SDS polyacrylamide gel electrophoresis; biological signal transduction; cell cycle; cell cycle proteins; cell death; cellular pathology; chromatin; enzyme activity; epithelium; flow cytometry; free radical oxygen; histones; hydrogen peroxide; intracellular transport; mass spectrometry; matrix assisted laser desorption ionization; mitogen activated protein kinase; phosphotransferases; renal toxin; renal tubule

DESCRIPTION (provided by applicant): Mechanisms of cell death are usually classified into two pathways, apoptosis and necrosis. However, it has been proposed by the American Society of Toxicologic Pathologists that the term oncosis, with its root meaning of "swelling" be used as the alternate descriptor of cell death occurring by non-apoptotic pathways. Necrosis more accurately describes the consequences of oncotic cell death, usually the death of a large number of cells which results in moderate to severe tissue injury. Oncosis is a form of cell death that typically occurs in response to toxic injury, including that induced by chemical exposure and reactive oxygen species (ROS). ROS are involved in the initiation and progression of a variety of human diseases and toxicities associated with chemical exposure. An understanding of the factors that regulate the cellular response to ROS and of the molecular mechanisms by which they interact with cellular constituents, and the consequences of such interactions, are important fundamental goals of biomedical research. The generation of ROS has been implicated in the pathogenesis of many pathological conditions. We have been using an in vitro model, in which H202 is generated in situ following the addition of TGHQ to LLC-PK1 cells, to investigate the cellular and molecular response of renal proximal tubule epithelial cells to oxidant-induced injury. Rigid controls function to prevent repeated rounds of DNA replication (S-phase arrest) without intervening mitoses, or the initiation of mitosis (G2M arrest) before DNA replication is complete ("mitotic catastrophe"). Loss of these cell cycle checkpoints after DNA damage may permit premature entry into mitosis. Our Preliminary data indicate that ROS-induced ERK activation contributes to oncotic cell death of LLC-PK1 cells by a mechanism that involves premature chromatin condensatior (PCC) and premature entry into mitosis. Four Specific Aims are proposed to test four inter-related hypotheses. (1) ERK activation is coupled to PCC and mitotic catastrophe via the activation of downstream histone H3 kinases. (2) PARP mediated ADP-ribosylation of histones facilitates histone H3 phosphorylation, and these post-translational modifications, perhaps in combination with additional modifications, are required for PCC and mitotic catastrophe. (3) ROS interfere with one or more components of the DNA damage check point system, driving the cells into premature mitosis, and subsequently death by mitotic catastrophe. (4) ROS induce the inappropriate nuclear translocation of cell cycle regulators, promoting premature mitosis. Our data, and that of others, indicate that responses to stress that usually result in oncotic cell death (and tissue necrosis) can indeed be manipulated, at the genetic and pharmacological level, to produce a potentially favorable (survivable) tissue response. Experiments proposed in the present application are designed to address this possibility. Basic knowledge of the mechanisms by which ROS induce cell death may yield strategies for clinical interventions in pathologies in which ROS play a prominent role

描述（申请人提供）：细胞死亡的机制通常分为凋亡和坏死两种途径。然而，美国毒理学病理学家协会提出，“肿瘤”一词，其词根意为“肿胀”，可作为非凋亡途径发生的细胞死亡的替代描述。坏死更准确地描述了肿瘤细胞死亡的后果，通常是大量细胞死亡，导致中度至重度组织损伤。肿瘤是细胞死亡的一种形式，通常发生在毒性损伤的反应中，包括化学暴露和活性氧（ROS）引起的损伤。活性氧参与了与化学物质接触有关的各种人类疾病和毒性的发生和发展。了解调节细胞对活性氧反应的因素、它们与细胞成分相互作用的分子机制以及这种相互作用的后果，是生物医学研究的重要基础目标。活性氧的产生与许多病理条件的发病机制有关。我们一直在使用体外模型，在LLC-PK1细胞中添加TGHQ后原位生成H202，以研究肾近端小管上皮细胞对氧化诱导损伤的细胞和分子反应。刚性控制的作用是防止DNA重复复制（s期阻滞）而不干预有丝分裂，或在DNA复制完成之前开始有丝分裂（G2M阻滞）（“有丝分裂灾难”）。DNA损伤后失去这些细胞周期检查点可能导致有丝分裂过早进入。我们的初步数据表明，ros诱导的ERK激活通过一种涉及过早染色质凝聚（PCC）和过早进入有丝分裂的机制，有助于LLC-PK1细胞的肿瘤细胞死亡。提出了四个具体目标来检验四个相互关联的假设。(1) ERK激活通过下游组蛋白H3激酶的激活与PCC和有丝分裂突变耦合。(2) PARP介导的组蛋白adp核糖基化促进了组蛋白H3磷酸化，这些翻译后修饰，可能与其他修饰相结合，是PCC和有丝分裂突变所必需的。(3)活性氧干扰DNA损伤检查点系统的一个或多个组分，导致细胞过早有丝分裂，并随后因有丝分裂灾难而死亡。(4)活性氧诱导细胞周期调控因子不适当的核易位，促进有丝分裂过早发生。我们和其他人的数据表明，通常导致肿瘤细胞死亡（和组织坏死）的应激反应确实可以在遗传和药理学水平上进行操纵，以产生潜在的有利（可存活的）组织反应。本应用程序中提出的实验旨在解决这种可能性。了解ROS诱导细胞死亡的基本机制，可以为ROS发挥重要作用的病理的临床干预提供策略