Translation initiation in cardiac intercellular communication and stress-induced remodeling

心脏细胞间通讯和应激诱导重塑中的翻译起始

• 批准号: 9384399
• 负责人: James William Smyth
• 金额: $ 39.37万
• 依托单位: VIRGINIA POLYTECHNIC INST AND ST UNIV
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9384399
• 关键词: 5' Untranslated Regions; Animals; Arrhythmia; Attention; Cardiac; Cardiac Myocytes; Cardiovascular Diseases; Cause of Death; Cell model; Cells; Code; Communication; Connexin 43; Coupling; Data; Defect; Elements; Event; Gap Junctions; Genes; Genetic Transcription; Genetic Translation; Goals; Heart; Heart Diseases; Heart Hypertrophy; Human; Hypertrophy; Hypoxia; Intercalated disc; Internal Ribosome Entry Site; Ion Channel; Ischemia; Isoproterenol; Knowledge; Laboratories; Lead; Maintenance; Messenger RNA; Mus; Myocardial Ischemia; Myocardium; Pathologic; Pathway interactions; Process; Protein Biosynthesis; Protein Isoforms; Proteins; Proteome; RNA-Binding Proteins; Recruitment Activity; Regulation; Regulatory Element; Regulatory Pathway; Research; Ribosomes; Role; Slice; Stress; Structure; System; Testing; Therapeutic; Tissues; Trans-Activators; Transcript; Transforming Growth Factor beta; Translating; Translation Initiation; Translational Regulation; Translations; United States; Viral; Work; base; biological adaptation to stress; epithelial to mesenchymal transition; heart cell; insight; intercellular communication; polypeptide; prevent; programs; sudden cardiac death

SUMMARY Reductions in intercellular communication occur in almost all forms of heart disease and lead to the arrhythmias of sudden cardiac death. The most intensely studied component of the intercalated disc of the working cardiomyocyte is the connexin 43 (Cx43) gap junction. The Cx43 gene, GJA1, encodes a polycistronic mRNA that undergoes internal translation events yielding truncated polypeptides capable of modulating gap junction formation and subject to altered regulation during stress such as ischemia and hypertrophy. Such internal translation within protein coding sequences of mammalian mRNAs has only recently been identified, and a substantial gap in the knowledge exists as to how this process is regulated by the cell and if manipulation of upstream regulatory pathways and associated proteins can be harnessed therapeutically to restore normal intercellular communication in diseased hearts. The objective of this application is to provide mechanistic insight into the role of altered translation initiation in pathological Cx43 gap junction regulation and remodeling. This work is significant because it will identify altered translation initiation as a common stress response in the heart and provide fundamental understanding of regulation of electrical communication through rapid alteration of the proteome by ribosomal initiation. Our central hypothesis is that dynamic regulation of the translational landscape of the cell governs intercellular communication, is vital in maintenance of proper cardiac electrical coupling, and is altered by the integrated stress response during pathological remodeling of the heart. We will test our central hypothesis with the following specific aims: AIM 1: Determine the role of altered translation initiation in gap junction regulation. The working hypothesis for this aim is that a cellular program exists at the level of translation initiation which regulates transition from a `junctional' to a `non- junctional' state. AIM 2: Delineate the regulatory elements of GJA1 mRNA critical for internal translation initiation. The working hypothesis for this aim is that GJA1 mRNA harbors sequence- and structure-based elements necessary for internal translation to occur via recruitment of specific RNA binding proteins. AIM 3: Test if modulation of translation initiation protects against pathological cardiac remodeling. Our working hypothesis for this aim is that the integrated stress response (ISR) alters translation initiation of GJA1, reducing GJA1-20k expression and limiting gap junction formation in stressed and hypertrophic myocardium. The work outlined in this proposal is significant because it will (i) provide mechanistic insight into the role of internal translation in regulation of gap junctions and intercellular communication during stress (ii) determine how this relates to pathological remodeling in hypertrophic and ischemic hearts, and (iii) test if modulation of internal translation is a viable therapeutic strategy for human heart disease.

概括 细胞间交流的减少几乎以所有形式的心脏病发生，并导致 心脏死亡的心律不齐。研究的最深入研究的组件 工作心肌细胞是连接43（CX43）间隙连接点。 CX43基因GJA1编码一个polycistronic 经历内部翻译事件的mRNA产生能够调节间隙的截短多肽 在缺血和肥大等压力期间，结的结构会改变调节。这样的 哺乳动物mRNA的蛋白质编码序列内的内部翻译直到最近才被鉴定出来， 知识存在很大的差距，即有关该过程如何受细胞调节以及是否存在 操纵上游调节途径和相关蛋白质可以在治疗上利用 恢复患病心脏中的正常细胞间交流。该应用的目的是提供 机械性的洞察力对改变的转化启动在病理CX43间隙连接调节中的作用和 重塑。这项工作很重要，因为它将确定变化的翻译开始是一种共同的压力 心脏的反应，并通过 核糖体开始对蛋白质组的快速改变。我们的中心假设是对 细胞的翻译局势控制细胞间通信，对于维持适当的维护至关重要 心脏电气耦合，并通过病理重塑期间的综合应力反应改变 心。我们将以以下特定目的测试中心假设：目标1：确定的作用 间隙连接调节中翻译启动的改变。这个目的的工作假设是细胞 程序存在于翻译启动级别，该启动的级别调节了从“连接”到``非 - 交界处的状态。目标2：描述GJA1 mRNA的调节元素至关重要的内部翻译 引发。此目的的工作假设是GJA1 mRNA携带序列和基于结构的序列 内部翻译通过募集特定的RNA结合蛋白发生所需的元素。目标3： 测试翻译起始的调节是否可以防止病理心脏重塑。我们的 为此目标的工作假设是，综合应力反应（ISR）改变了GJA1的翻译启动， 在应力和肥厚性心肌中降低GJA1-20K表达并限制间隙连接形成。 该提案中概述的工作很重要，因为它将（i）提供机械洞察力的洞察力 压力期间间隙连接和细胞间通信调节的内部翻译（II）确定 这与肥厚和缺血性心脏中的病理重塑有关，以及（iii）测试是否调制 内部翻译是人心脏病的可行治疗策略。