Linker cell death regulation in C. elegans

线虫中的连接细胞死亡调节

基本信息

批准号：
10462716
负责人：
Shai Shaham
金额：
$ 36.44万
依托单位：
ROCKEFELLER UNIVERSITY
依托单位国家：
美国
项目类别：
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/10462716
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

项目摘要

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新型形态保守的非凋亡细胞的分子基础我们发现了发育细胞死亡程序，并确定了其在哺乳动物发育和发育中的作用疾病。程序性细胞死亡是主要的细胞命运。细胞凋亡是一种广泛研究的细胞死亡过程，需要半胱天冬酶蛋白酶，并伴有染色质压缩和细胞质收缩。令人惊讶的是，缺乏凋亡效应子的小鼠能够存活到成年。这些观察结果表明，非细胞凋亡可能在动物发育中发挥关键作用。虽然促进坏死细胞死亡的基因已经描述过，这些不是开发所必需的。因此，替代发育细胞是否死亡途径是否存在，如果存在，什么分子机制控制其执行，是一个主要的突出问题问题。我们对秀丽隐杆线虫连接细胞的研究提供了直接证据，表明不依赖半胱天冬酶的非- 细胞凋亡途径在动物发育过程中发挥作用。连接细胞死亡发生在缺乏线虫半胱天冬酶和其他凋亡基因也不是必需的，也不是与自噬有关的基因或坏死。垂死的连接细胞的形态特征是缺乏染色质凝聚，细胞核呈锯齿形，细胞质细胞器肿胀。值得注意的是，细胞死亡具有相似的特征（连接子细胞型死亡，LCD）也发生在脊椎动物中，并且是神经元变性的特征多聚谷氨酰胺疾病。我们最近描述了控制线虫 LCD 的途径。这是第一个这样的非凋亡发育细胞死亡程序的框架。 LCD由Wnt信号控制与发育时序和 MAPKK 通路并行发挥作用，以控制非典型活性 HSF-1，一种保守的热休克转录因子。 let-70/Ube2D2，编码保守的 E2 泛素- 结合酶，是 HSF-1 的关键靶点。 E3 组件 CUL-3/cullin、RBX-1、BTBD-2 和 EBAX-1 与用于 LCD 的 LET-70/UBE2D2 配合使用。我们最近的证据表明组蛋白甲基化可能是一个目标该途径的作用，可能导致全基因组染色质开放，允许核酸酶进入和 DNA 降解。 LCD 通路成分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，让人想起引起神经退行性变的聚Q蛋白。和 tir-1/Sarm 和 BTBD-2 促进轴突切除术后远端轴突变性，支持保守的细胞解体作用。我们最近展示了用激酶抑制剂星孢菌素 (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揭示 LCD 通路目标，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，并测试染色质修饰和 DNA 降解中这些物质的假设途径。 (2) 确定EBAX-1目标基因并评估 LCD 控制中的作用。 (3) 表征哺乳动物细胞中 STS 诱导的死亡，定义使用秀丽隐杆线虫 LCD 进行保护，并鉴定相关基因。