Characterization of endocrine signaling and RNAi pathways as mechanisms regulating environmental programming in C. elegans

内分泌信号传导和 RNAi 途径作为调节秀丽隐杆线虫环境编程机制的表征

• 批准号: 10409696
• 负责人: SARAH E HALL
• 金额: $ 30万
• 依托单位: SYRACUSE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-17 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10409696
• 关键词: Adult; Animal Model; Animals; Barker Hypothesis; Biochemical; Biochemical Genetics; Biological Models; Caenorhabditis elegans; Candidate Disease Gene; Childhood; Cues; Data; Defect; Development; Disease; Endocrine; Exhibits; FAT gene; Famines; Fatty Acids; Fatty acid glycerol esters; Fertility; Fetus; Gene Expression; Gene Targeting; Generations; Genes; Genetic; Genetic Transcription; Germ Cells; Germ Lines; Goals; Health; Human; Hypothalamic structure; Individual; Inherited; Intestines; Investigation; Life; Longevity; Low Birth Weight Infant; Mediating; Memory; Messenger RNA; Metabolic; Molecular; Nematoda; Neurosecretory Systems; Nuclear; Nutritional; Obesity; Oleic Acids; Outcome; Parents; Pathway interactions; Phenotype; Physiology; Pituitary-Adrenal System; Production; RNA Binding; RNA Interference; Recording of previous events; Regulation; Reproduction; Rodent Model; Role; Signal Pathway; Signal Transduction; Small Interfering RNA; Small RNA; Starvation; Sterility; Steroids; Stress; System; Testing; Tissue-Specific Gene Expression; Untranslated RNA; Up-Regulation; Work; base; developmental genetics; early childhood; early experience; epigenetic regulation; experience; experimental study; fatty acid metabolism; fetal; gene function; hormonal signals; human model; in utero; mature animal; sensor; steroid hormone; transgenerational epigenetic inheritance

Increasing evidence suggests that fetal and childhood experiences impact adult disease in humans through changes in tissue-specific gene expression states and sustained altered function of the neuroendocrine HPA axis. However, the molecular pathways by which environmental cues experienced in utero or early childhood result in long-lasting effects associated with adult disease, and how they can be inherited over generations, are not well understood. Caenorhabditis elegans nematodes provide a unique animal model system in which to explore the mechanisms of environmental programming of gene expression due to early experience. Although adult animals that experienced environmental stress early in development appear grossly identical to animals that experienced favorable conditions, these adults retain a cellular memory of their environmental history that is manifested by changes in gene expression and fertility that are distinct for the particular stress experienced. Animals that experienced early-life starvation exhibited decreased fertility compared to controls, which is dependent upon the upregulation of conserved endocrine signaling pathways and the CSR-1 RNAi pathway. Interestingly, these endocrine signaling pathways, steroid hormone signaling and fatty acid metabolism, are also upregulated in long-lived animals lacking a germ line. In addition, the reduced fertility phenotype of starvation-stressed animals is also inherited for at least two generations via the HRDE-1 RNAi pathway. The overall goal of this proposal is to investigate how pathways that can promote longevity in germline-less animals can also modulate reproduction in animals that experienced nutritional stress. The specific aims of this proposal include: 1) investigate the roles of steroid signaling and fatty acid metabolism in the regulation of fertility after early-life starvation. This aim proposes genetic and biochemical experiments to test the hypothesis that DAF-12/NHR acts as a “fat sensor” to modulate germ line production based on levels of stored fat by directly regulating gene(s) with functions in promoting the onset of germline proliferation. 2) Using biochemical and developmental genetics experiments, test whether the increased fatty acid metabolism in csr-1 hypomorph adults is due to direct regulation of fat genes by CSR-1 in the intestine, or an indirect effect of reduced fertility in the csr-1 hypomorph, as germ line defects may trigger these pathways. 3) Determine the mechanisms of inheritance for reduced fertility in progeny of animals that experienced nutritional stress. Experiments will test whether steroid signaling and fatty acid metabolism genes are also upregulated in F1 progeny. HRDE-1 associated siRNAs will also be deep sequenced in the progeny to identify target genes contributing to the reduced fertility phenotype. Together, these experiments will investigate how pathways that promote somatic longevity in germline-less animals can also modulate fertility due to early life starvation, and how RNAi pathways contribute to inheritance of metabolic programming.

越来越多的证据表明，胎儿和儿童时期的经历通过以下方式影响人类成年疾病： 组织特异性基因表达状态的变化和神经内分泌 HPA 功能的持续改变 轴。然而，在子宫内或幼儿期经历环境线索的分子途径 导致与成人疾病相关的长期影响，以及它们如何代代相传 不太理解。 秀丽隐杆线虫提供了一个独特的动物模型系统，可用于探索 由于早期经验，基因表达的环境编程机制。虽然成年了 在发育早期经历过环境压力的动物与那些在发育早期经历过环境压力的动物看起来非常相似 经历了有利的条件后，这些成年人保留了其环境历史的细胞记忆，即 表现为基因表达和生育力的变化，这些变化对于所经历的特定压力是不同的。 与对照组相比，经历过生命早期饥饿的动物的生育能力下降，这是 依赖于保守内分泌信号通路和 CSR-1 RNAi 通路的上调。 有趣的是，这些内分泌信号通路、类固醇激素信号传导和脂肪酸代谢是 在缺乏种系的长寿动物中也上调。此外，生育力降低的表型 饥饿应激的动物也通过 HRDE-1 RNAi 途径遗传至少两代。 该提案的总体目标是研究如何在无种系细胞中促进长寿的途径 动物还可以调节经历营养应激的动物的繁殖。本次活动的具体目标 提案包括：1）研究类固醇信号传导和脂肪酸代谢在调节中的作用 早年饥饿后的生育能力。这一目标提出了遗传和生化实验来检验这一假设 DAF-12/NHR 充当“脂肪传感器”，根据储存的脂肪水平调节种系生产 直接调节具有促进种系增殖开始功能的基因。 2）使用生化法 和发育遗传学实验，测试csr-1次形体中脂肪酸代谢是否增加 成人是由于肠道内CSR-1对脂肪基因的直接调节，或生育能力降低的间接影响 在 csr-1 亚型中，因为种系缺陷可能会触发这些途径。 3）确定机制 经历营养压力的动物后代的生育能力下降的遗传。实验将测试 F1 后代中类固醇信号传导和脂肪酸代谢基因是否也上调。 HRDE-1 相关的 siRNA 也将在后代中进行深度测序，以确定有助于 生育表型降低。这些实验将共同研究促进体细胞的途径如何 无种系动物的长寿也可以调节由于早期生命饥饿而导致的生育力，以及 RNAi 如何调节生育力 途径有助于代谢编程的遗传。