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: 10207739
• 负责人: James William Smyth
• 金额: $ 39.61万
• 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/10207739
• 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; Exposure to; 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; 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; recruit; 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.

摘要 细胞间通讯的减少几乎发生在所有形式的心脏病中，并导致 心脏性猝死的心律失常。研究最深入的成分是在地球表面的 工作心肌细胞是连接蛋白43(Cx43)的缝隙连接。Cx43基因GJA1编码一个多顺反子 经历内部翻译事件产生能够调节GAP的截短多肽的mRNA 在应激期间，如缺血和肥大，连接形成并受到改变的调节。是这样的 哺乳动物mRNAs的蛋白质编码序列内的内部翻译直到最近才被鉴定， 关于细胞如何调节这一过程以及是否 上游调控通路和相关蛋白的操纵可以在治疗上被利用 使患病心脏恢复正常的细胞间通讯。此应用程序的目标是提供 翻译起始改变在病理性Cx43缝隙连接调控中作用的机械性洞察 改建。这项工作意义重大，因为它将把改变的翻译起始识别为常见的重音 心脏的反应，并提供了通过电子通信的调节的基本理解 通过核糖体启动蛋白质组的快速改变。我们的中心假设是动态调节 细胞的翻译格局支配着细胞间的交流，对维持正常的 心脏电耦合，并在病理重塑过程中被整合的应激反应改变 心脏。我们将通过以下具体目标来检验我们的中心假设：目标1：确定 改变了缝隙连接调控中的翻译起始。这个目标的工作假设是，一个细胞 程序存在于翻译启动的层面，它规定了从连接词到非连接词的转换 交界性状态。目的2：描述GJA1基因对内部翻译起关键作用的调控元件 入会仪式。这一目的的工作假设是GJA1 mRNA含有基于序列和结构的 通过招募特定的RNA结合蛋白进行内部翻译所需的元件。目标3： 测试翻译起始的调节是否能预防病理性心脏重构。我们的 为此的工作假设是，整合应激反应(ISR)改变了GJA1的翻译起始， 减少GJA1-20k在应激和肥厚心肌中的表达并限制缝隙连接的形成。 本提案中概述的工作意义重大，因为它将(I)提供对角色的机械性洞察 应激过程中缝隙连接和细胞间通讯的内部翻译调控(II)确定 这与肥厚和缺血心脏的病理重塑有何关系，以及(Iii)测试是否调节 内部翻译是人类心脏病的一种可行的治疗策略。