Linker cell death regulation in C. elegans

线虫中的连接细胞死亡调节

• 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
• 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

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学保守的非凋亡性细胞因子的分子基础。 我们发现的发育细胞死亡程序，并确定其在哺乳动物发育和 疾病程序性细胞死亡是一种主要的细胞命运。细胞凋亡是一种被广泛研究的细胞死亡过程， 需要半胱天冬酶蛋白酶，并伴有染色质致密化和细胞质收缩。 令人惊讶的是，缺乏凋亡效应子的小鼠可以存活到成年。这些观察表明，非 凋亡性细胞死亡可能在动物发育中起关键作用。虽然促进坏死细胞死亡的基因 已经描述了，这些不是发展所必需的。因此，替代性发育细胞 死亡途径存在，如果是这样的话，什么样的分子机制控制着它们的执行，是一个重大的悬而未决的问题。 问题我们对C. elegans连接细胞提供了直接证据， 凋亡细胞死亡途径在动物发育过程中起作用。连接细胞死亡发生在缺乏 C.线虫半胱天冬酶和其他凋亡基因也不是必需的，也不是自噬相关基因 或坏死。垂死的连接细胞的形态特征是缺乏染色质凝聚， 细胞核有锯齿状突起，细胞器肿胀。值得注意的是，具有相似特征的细胞死亡（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。 多谷氨酰胺病我们最近描述了一个控制C的途径。elegans LCD。这是第一次这样的 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途径平行发挥作用，以控制 HSF-1，一种保守的热休克转录因子。let-70/Ube 2D 2，编码保守的E2泛素- 结合酶是HSF-1的关键靶标。E3组件CUL-3/cullin、RBX-1、BTBD-2和EBAX-1 LCD用LET-70/UBE 2D 2功能。我们最近的证据表明，组蛋白甲基化可能是一个目标， 这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途径组分促进脊椎动物细胞退化过程。pqn-41，一种谷氨酰胺， 富含蛋白质，使人联想到导致神经变性的polyQ蛋白。和tir-1/Sarm和BTBD-2促进 轴突切断后的远端轴突变性，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）处理哺乳动物细胞导致LCD样死亡。这里我们 将在这些研究的基础上揭示LCD途径的目标，并研究与哺乳动物的相关性。我们将：（1） 研究SAMS-4（BTBD-2靶标）和NUC-1（DNaseII酶）在LCD中的作用，并测试其在LCD中的作用。 这些在染色质修饰和DNA降解中的假设途径。(2)确定EBAX-1靶标 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 与C. elegans LCD，并鉴定相关基因。