Dissecting injury-responsive gene expression during zebrafish heart regeneration

剖析斑马鱼心脏再生过程中损伤反应基因的表达

• 批准号: 10320794
• 负责人: Junsu Kang
• 金额: $ 38.21万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-20 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10320794
• 关键词: Adult; Automobile Driving; Bar Codes; Biological Assay; Cardiac; Cardiac Myocytes; Cells; Computer Analysis; Cues; Data; Development; Elements; Endocardium; Enhancers; Epicardium; Fishes; Gene Expression; Gene Expression Regulation; Generations; Genes; Genetic; Genetic Transcription; Genome; Goals; Heart; Heart Injuries; Heart failure; Injury; Interleukins; Knock-in; Knowledge; Leptin; Link; MAP2K1 gene; Mammals; Mediating; Modeling; Morbidity - disease rate; Mus; Natural regeneration; Pathway interactions; Pharmacology; Process; Reactive Oxygen Species; Regenerative capacity; Regenerative research; Regenerative response; Regulator Genes; Regulatory Element; Reporter; Reporter Genes; Reporting; Repression; Role; Signal Transduction; System; Testing; Therapeutic; Transgenic Organisms; Zebrafish; base; cardiac regeneration; cardiac repair; cytokine; epigenomics; eye regeneration; gain of function; genetic approach; heart damage; in vivo; injured; innovation; insight; loss of function; mortality; mutant; overexpression; paracrine; programs; regenerative; response to injury; spatiotemporal; tool; transcriptome

PROJECT SUMMARY/ABSTRACT Adult mammals poorly regenerate injured hearts. In contrast, adult zebrafish possess a remarkable capacity to regenerate damaged hearts. Combined with available genetic tools, this capacity makes zebrafish a powerful system for deciphering the mechanisms underlying heart regeneration. Upon injury, the endocardium and epicardium are rapidly activated to secrete paracrine factors that facilitate heart regeneration. Heart regeneration research has focused mostly on identifying the secreted factors that trigger regenerative programs, yet little is known about the regulatory mechanisms controlling their expression, a proximal step in the regenerative process. Proper spatiotemporal regulation of these genes is essential for the intricate and tightly coordinated processes underlying cardiac regeneration. Thus, elucidating gene regulatory mechanisms governing injury-responsive gene expression will provide insights into potential therapeutic strategies based on stimulating paracrine effectors. Previously, we identified leptin b (lepb) as an injury-induced factor secreted by the endocardium. Importantly, we showed that the cardiac regeneration enhancer linked to lepb (LEN) is robustly activated by cardiac injury, maintains activity during regeneration, and then returns to a naïve state upon completion of regeneration. We also identified a cardiac injury-responsive enhancer linked to interleukin 11a (il11a), which encodes a proregenerative cytokine structurally similar to lepb. We showed that zebrafish injury-responsive enhancers drive reporter-gene expression in injured mouse hearts, indicating that the mechanisms mediating injury-induced enhancer function are evolutionarily conserved. Based on these findings, we propose two aims to decipher gene regulatory mechanisms governing heart regeneration. The central hypothesis is that cardiac injury-responsive enhancers establish the transcriptional state of genes encoding paracrine factors that facilitate heart repair. Aim 1 will determine the transcriptional mechanisms underlying cardiac injury-responsive enhancer activity. We discovered that cardiac LEN (cLEN) is not only activated by injury but also actively repressed in the absence of injury. We will employ transgenic assays, genetic and pharmacological approaches, as well as epigenomic and computational analyses to test the hypothesis that repression and activation mechanisms collectively determine cardiac injury-responsive enhancer function to confer injury-dependent cardiac gene transcription. Aim 2 will use loss-of-function and gain-of-function studies to define how il11a controls heart regeneration and to dissect its injury-responsive enhancer. Elucidating the transcriptional mechanisms and function of crucial enhancer-regulated factors secreted upon cardiac injury will transform knowledge on how injury signals are transduced to facilitate heart regeneration.

项目总结/摘要 成年哺乳动物很难再生受伤的心脏。相比之下，成年斑马鱼具有非凡的能力， 再生受损的心脏结合现有的遗传工具，这种能力使斑马鱼成为一种强大的 这是一个破译心脏再生机制的系统。在受伤时， 心外膜被迅速激活以分泌促进心脏再生的旁分泌因子。心脏再生 研究主要集中在确定触发再生程序的分泌因子上，但很少有 已知控制其表达的调节机制，这是再生过程中的近端步骤。 这些基因的适当时空调节对于复杂和紧密协调的过程至关重要 潜在的心脏再生因此，阐明基因调控机制，管理损伤响应 基因表达将为基于刺激旁分泌的潜在治疗策略提供见解 效应器此前，我们确定瘦素B（lep B）是心内膜分泌的一种损伤诱导因子。 重要的是，我们发现与lepb相关的心脏再生增强子（LEN）被 心脏损伤，在再生过程中保持活性，然后在完成再生后恢复到原始状态。 再生我们还鉴定了与白细胞介素11 a（il 11 a）相关的心脏损伤应答增强子， 编码结构上类似于lepB的促再生细胞因子。我们发现斑马鱼对伤害的反应 增强子驱动受损小鼠心脏中的转录因子基因表达，表明介导 损伤诱导增强子功能在进化上是保守的。基于这些发现，我们提出了两个目标， 解读心脏再生的基因调控机制。核心假设是心脏 损伤应答增强子建立了编码旁分泌因子的基因的转录状态， 心脏修复目的1将确定心脏损伤应答增强子的转录机制 活动我们发现，心脏LEN（cLEN）不仅被损伤激活，而且在心肌细胞中被积极抑制。 没有受伤。我们将采用转基因检测，遗传和药理学方法，以及 表观基因组和计算分析，以测试这一假设，抑制和激活机制， 共同确定心脏损伤应答增强子功能，以赋予损伤依赖性心脏基因 转录。Aim 2将使用功能丧失和功能获得研究来定义il 11 a如何控制心脏 再生和解剖其损伤响应增强剂。阐明转录机制， 心脏损伤后分泌的关键增强子调节因子的功能将改变关于如何 损伤信号被转导以促进心脏再生。