Mechanisms of osmosensing and osmotic stress responses in tilapia

罗非鱼渗透感应和渗透应激反应的机制

• 批准号: 1355098
• 负责人: Dietmar Kültz
• 金额: $ 65.89万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-15 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1355098&HistoricalAwards=false
• 关键词: Mechanisms; osmosensing; osmotic; stress; responses

Remarkable progress has been made in understanding the effector mechanisms of osmoregulation in fishes and many other animals. In contrast, less is known about the mechanisms by which these effectors are regulated, how osmotic changes in the environment are perceived, and how osmosensory information is transduced via intracellular signaling pathways to the osmoregulatory effectors. By approaching these questions starting from a robust and tractable osmoregulatory effector system to identify its regulatory elements, the project addresses a large gap in the current knowledge about fish osmoregulation/ fluid and electrolyte homeostasis. Tilapia (Oreochromis mossambicus) represent a superb model for studying mechanisms of osmosensing and osmotic stress signaling because they tolerate an extremely wide range of environmental salinity. Their genome has been sequenced and proteome well-annotated. The research supported by this award will investigate the mechanisms and implications associated with hyperosmotic induction of the myo-inositol biosynthesis pathway. This research project has broad implications for biology because myo-inositol and phosphoinosite signaling as well as osmotic stress responses are common to all eukaryotes. It has basic implications for agricultural development because studying mechanisms and implications associated with activation of compatible osmolyte synthesis pathways could lead to increasing salt and drought tolerance. Understanding the role of myo-inositol in the regulation of key intracellular signaling pathways and energy homeostasis is also significant in the light of stress-related disorders. The PIs lab has generated significant resources in the past to advance the study of osmosensory and osmoregulatory mechanisms in tilapia, including quantitative proteomics workflows and several highly osmotolerant cell lines. Preliminary data show that both enzymes involved in this pathway, myo-inositol phosphate synthase (MIPS) and inositol monophosphatase 1 (IMPase 1), as well as myo-inositol levels are extremely highly upregulated during hyperosmotic stress in multiple tilapia tissues and cell lines. Thus, this pathway represents a robust system for the proposed studies. The project aims to identify osmoresponsive cis elements in the MIPS and IMPase1 genes and test the hypothesis that such elements are necessary for hyperosmotic induction of the myo-inositol biosynthesis pathway. Moreover, the hypothesis that MIPS and IMPase1 influence cellular osmoregulation beyond myo-inositol being a compatible osmolyte will be tested. Specifically, it is proposed that MIPS and IMPase 1 directly interact with other proteins involved in osmoprotection and that their regulation indirectly affects cellular phosphoinosite signaling (PI3K/ PTEN/Akt and PLC/PKC/IP3 pathways) and energy metabolism (by sequestering glucose-6-phosphate). The project uses sophisticated proteomics tools and workflows to capture molecular phenotypes associated with osmotic stress signaling in an unprecedented fashion. This unique combination of resources will significantly enhance our understanding of osmotic stress signaling mechanisms and provide novel insight into evolutionary driving forces that have shaped myo-inositol as a key metabolite in most organisms. Dissemination of activities and results of this project will be done via peer-reviewed publications, conference presentations, seminars, and broader outreach avenues, including engagement of K12 students and educators, aquaculture producers, community groups, and conservation organizations in research. A public lab website will be developed to showcase research and outreach activities. Two graduate students will be trained and each of them will supervise an undergraduate intern. Priority will be given to recruit students from underrepresented minorities.

在了解鱼类和许多其他动物的渗透调节效应机制方面已经取得了显着进展。相比之下，人们对这些效应器的调节机制、如何感知环境中的渗透压变化以及如何通过细胞内信号通路将渗透感应信息转导至渗透调节效应器知之甚少。通过从强大且易于处理的渗透调节效应器系统开始解决这些问题，以确定其调节元件，该项目解决了当前有关鱼类渗透调节/液体和电解质稳态知识中的巨大差距。 罗非鱼（Oreochromis mossambicus）是研究渗透传感和渗透应激信号传导机制的绝佳模型，因为它们能耐受极宽范围的环境盐度。它们的基因组已被测序，蛋白质组已得到很好的注释。 该奖项支持的研究将调查与肌醇生物合成途径高渗诱导相关的机制和影响。 该研究项目对生物学具有广泛的影响，因为肌醇和磷酸肌醇信号传导以及渗透应激反应对所有真核生物来说都是常见的。它对农业发展具有基本意义，因为研究与相容渗透剂合成途径激活相关的机制和影响可能会导致提高耐盐性和耐旱性。鉴于应激相关疾病，了解肌醇在关键细胞内信号通路和能量稳态调节中的作用也具有重要意义。 PI 实验室过去已经产生了大量资源来推进罗非鱼渗透感应和渗透调节机制的研究，包括定量蛋白质组学工作流程和几种高渗透压耐受细胞系。初步数据表明，在多种罗非鱼组织和细胞系的高渗应激过程中，参与该途径的两种酶，肌醇磷酸合酶（MIPS）和肌醇单磷酸酶1（IMPase 1），以及肌醇水平都极度上调。因此，该途径代表了拟议研究的强大系统。该项目旨在鉴定 MIPS 和 IMPase1 基因中的渗透响应顺式元件，并检验这些元件对于肌醇生物合成途径的高渗诱导所必需的假设。此外，MIPS 和 IMPase1 除了肌醇作为相容渗透剂之外还影响细胞渗透压调节的假设也将得到测试。具体来说，有人提出 MIPS 和 IMPase 1 直接与参与渗透保护的其他蛋白质相互作用，并且它们的调节间接影响细胞磷酸肌醇信号传导（PI3K/PTEN/Akt 和 PLC/PKC/IP3 途径）和能量代谢（通过隔离葡萄糖-6-磷酸）。该项目使用复杂的蛋白质组学工具和工作流程以前所未有的方式捕获与渗透应激信号相关的分子表型。 这种独特的资源组合将显着增强我们对渗透应激信号机制的理解，并为使肌醇成为大多数生物体中关键代谢物的进化驱动力提供新的见解。该项目的活动和结果将通过同行评审的出版物、会议演示、研讨会和更广泛的外展途径进行传播，包括让 K12 学生和教育工作者、水产养殖生产者、社区团体和保护组织参与研究。 将开发一个公共实验室网站来展示研究和外展活动。 将培训两名研究生，每人将指导一名本科生实习生。 将优先招收代表性不足的少数族裔的学生。