Linker cell death regulation in C. elegans

线虫中的连接细胞死亡调节

• 批准号: 10298197
• 负责人: Shai Shaham
• 金额: $ 36.44万
• 依托单位: ROCKEFELLER UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-05 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10298197
• 关键词: Adult; Animals; Apoptosis; Apoptotic; Autophagocytosis; Axotomy; Binding; CASP3 gene; CASP9 gene; Caenorhabditis elegans; Caspase; Cell Death; Cell Death Process; Cell Nucleus; Cell Survival; Cell physiology; Cells; Cessation of life; Characteristics; Chromatin; Complex; Cytoplasmic Organelle; DNA; DNA Methylation; Development; Disease; Distal; Enzymes; Genes; Genetic; Genetic study; Glutamine; Goals; Heat-Shock Response; Histones; Homologous Gene; Human; Light; Mammalian Cell; Mammals; Mediating; Methyltransferase; Mitogen-Activated Protein Kinase Kinases; Modeling; Molecular; Molecular Genetics; Morphology; Mus; Necrosis; Nematoda; Nerve Degeneration; Nuclear; Pathway interactions; Patients; Peptide Hydrolases; Physical condensation; Physical shape; Play; Prevalence; Process; Proteins; Regulation; Role; Staurosporine; Swelling; System; Tertiary Protein Structure; Testing; UBE2D2 gene; Ubiquitin; Ubiquitin-Conjugating Enzymes; Vertebrates; WNT Signaling Pathway; apoptotic protease-activating factor 1; axonal degeneration; biological adaptation to stress; cell type; chromatin modification; cullin-3; demethylation; gene induction; genome-wide; heat shock transcription factor; histone methylation; human disease; kinase inhibitor; methionine adenosyltransferase; mouse development; mouse model; multicatalytic endopeptidase complex; mutant; novel; nuclease; polyglutamine; programs; tool; transcription factor; ubiquitin-protein ligase

Our long-term goal is to understand the molecular basis of a novel morphologically-conserved non-apoptotic developmental cell-death program we uncovered, and to determine its roles in mammalian development and disease. Programmed cell death is a major cell fate. Apoptosis, an extensively studied cell death process, requires caspase proteases and is accompanied by chromatin compaction and cytoplasmic shrinkage. Surprisingly, mice lacking apoptotic effectors survive to adulthood. These observations suggest that non- apoptotic cell death may play key roles in animal development. Although genes promoting necrotic cell death have been described, these are not required for development. Thus, whether alternative developmental cell death pathways exist, and if so, what molecular mechanisms govern their execution, is a major outstanding question. Our studies of the C. elegans linker cell provide direct evidence that caspase-independent non- apoptotic cell death pathways operate during animal development. Linker cell death occurs in the absence of C. elegans caspases, and other apoptosis genes are also not required, nor are genes implicated in autophagy or necrosis. The morphology of a dying linker cell is characterized by lack of chromatin condensation, a crenellated nucleus, and swelling of cytoplasmic organelles. Remarkably, cell death with similar features (linker cell-type death, LCD) also occurs in vertebrates, and is characteristic of neuronal degeneration in polyglutamine diseases. We recently described a pathway governing C. elegans LCD. This is the first such framework for a non-apoptotic developmental cell-death program. LCD is controlled by Wnt signals that function in parallel with a developmental-timing and a MAPKK pathway to control non-canonical activity of HSF-1, a conserved heat-shock transcription factor. let-70/Ube2D2, encoding a conserved E2 ubiquitin- conjugating enzyme, is a key target of HSF-1. The E3 components CUL-3/cullin, RBX-1, BTBD-2, and EBAX-1 function with LET-70/UBE2D2 for LCD. Our recent evidence suggests that histone methylation may be a target of this pathway, likely resulting in genome-wide chromatin opening, allowing nuclease access and DNA degradation. LCD pathway components promote vertebrate cell-degenerative processes. pqn-41, a glutamine- rich protein, is reminiscent of polyQ proteins causing neurodegeneration. and tir-1/Sarm and BTBD-2 promote distal axon degeneration following axotomy, supporting conserved cell dismantling roles. We recently showed that treatment of mammalian cells with the kinase inhibitor staurosporin (STS) causes LCD like death. Here we will build on these studies to uncover LCD pathway targets, and study relevance to mammals. We will: (1) Investigate the role of SAMS-4, a BTBD-2 target, and NUC-1, a DNaseII enzyme, in LCD, and test an hypothesized pathway for these in chromatin modification and DNA degradation. (2) Identify EBAX-1 target genes and assess roles in LCD control. (3) Characterize STS-induced death in mammalian cells, define conservation with C. elegans LCD, and identify relevant genes.

我们的长期目标是了解一种新的形态保守的非凋亡细胞的分子基础 我们发现了发育中的细胞死亡程序，并确定了它在哺乳动物发育和 疾病。细胞程序性死亡是一种主要的细胞命运。细胞凋亡，一个被广泛研究的细胞死亡过程， 需要半胱氨酸蛋白酶，并伴随着染色质压缩和细胞质收缩。 令人惊讶的是，缺乏凋亡效应的小鼠可以存活到成年。这些观察表明，非 细胞凋亡性死亡可能在动物发育中起关键作用。尽管促进坏死细胞死亡的基因 已经描述过了，这些都不是开发所必需的。因此，替代发育细胞是否 死亡路径是存在的，如果是这样的话，什么分子机制支配着它们的执行，是一个主要的突出问题 问题。我们对线虫连接细胞的研究提供了直接证据，证明caspase不依赖于 细胞死亡途径在动物发育过程中起作用。链接器细胞死亡发生在没有 线虫caspase和其他凋亡基因也不是必需的，也不涉及自噬。 或坏死。垂死的连接细胞的形态特征是缺乏染色质凝集， 胞核呈网状，胞质细胞器肿胀。值得注意的是，具有相似特征的细胞死亡(链接器 细胞型死亡，LCD)也发生在脊椎动物中，是神经元变性的特征 多聚谷氨酰胺病。我们最近描述了一种控制线虫LCD的途径。这是第一次 非凋亡性发育细胞死亡计划的框架。LCD由WNT信号控制，该信号 与发育计时和MAPKK途径平行发挥作用，以控制 HSF-1，一个保守的热休克转录因子。Let-70/Ube2D2，编码一个保守的E2泛素- 结合酶是HSF-1的一个关键靶点。E3组分CUL-3/CULLIN、RBX-1、BTBD-2和EBAX-1 带LET-70/UBE2D2的LCD功能。我们最近的证据表明，组蛋白甲基化可能是一个目标 可能导致全基因组染色质开放，允许核酸酶访问和DNA 退化。LCD途径组件促进脊椎动物细胞退化过程。PQN-41，一种谷氨酰胺- 丰富的蛋白质，让人想起导致神经退化的多聚Q蛋白。和TIR-1/Sarm和BTBD-2促进 轴突切断后远端轴突变性，支持保守的细胞分解作用。我们最近展示了 用激酶抑制剂星形孢菌素(STS)处理哺乳动物细胞会导致LCD样死亡。在这里我们 将在这些研究的基础上发现LCD途径的靶点，并研究与哺乳动物的相关性。我们将：(1) 研究BTBD-2靶标SAMS-4和DNaseII酶NUC-1在LCD中的作用，并测试 它们在染色质修饰和DNA降解中的假想途径。(2)确定EBAX-1目标 基因和评估在LCD控制中的作用。(3)表征STS诱导的哺乳动物细胞死亡，定义 用秀丽线虫LCD进行保护，并鉴定相关基因。