Role of small RNAs in ischemic tissue repair

项目摘要 心血管疾病（CVD）仍然是死亡的主要原因，迫切需要确定 潜在的机制，并开发新的治疗方法。小卡哈尔体特异性RNA（scaRNA） 是进化上保守的非编码RNA，其引导特定核苷酸上的生化修饰， 如假尿苷化（pseudouridylation，PGD）和2′-O-核糖甲基化（2′-OMe）。这些修改在后... 剪接体小核RNA（snRNA）的转录变化和功能。最近的研究强调， scaRNA在保持剪接体保真度和心脏发育中的关键作用;然而，scaRNA的作用 急性心脏损伤及其修复尚未建立。 这 该提案旨在确定scaRNA的作用 在小鼠心肌梗死（MI）模型的心血管过程中， MI.我们的中心假设是心肌梗死后心脏中scaRNA 18的过度表达促进了心肌梗死后心肌细胞的阳性表达。 通过U4 snRNA的2′-OMe诱导治疗性血管生成并调节Wilms tumor 1（WT 1）进行重塑 表达，从而赋予心脏保护和改善心脏功能。我们的初步数据 证明1）使用无偏小RNA在MI后小鼠心脏中降低scaRNA 18表达 测序，2）scaRNA 18表达在分离的心脏内皮细胞（EC）中特异性下调， 3）scaRNA 18敲低（KD）损害小鼠中的管形成并诱导细胞凋亡 4）scaRNA 18过表达增强EC血管生成并抑制 体外应激诱导EC凋亡，5）scaRNA 18过表达的心脏EC细胞外囊泡保护 通过血管生成蛋白导致iPSC-心肌细胞死亡，6）MI心脏中2 '-O-甲基化水平降低 在scaRNA 18 KD小鼠的心脏EC中，7）突变体scaRNA 18缺乏引导U4上2′-OMe的结合位点 snRNA诱导EC细胞凋亡而不诱导应激，8）无偏质谱结果显示， scaRNA 18降低了scaRNA 18 KD心脏EC中的WT 1表达水平，9）在 scaRNA 18过表达使scaRNA 18介导的EC存活效应无效，和10） 通过VE-钙粘蛋白驱动的AAV 9的scaRNA 18减少离体心脏缺血/再灌注损伤后的梗死面积 并改善MI后小鼠的心脏功能（体内）。scaRNA 18是一个关键成分的假设， 心脏功能和修复将在以下三个具体目标中进行测试：在目标1中，我们将定义 scaRNA 18在心脏EC功能和心肌细胞存活中的作用;在目标2中，我们将确定scaRNA 18在心脏EC功能和心肌细胞存活中的分子作用。 scaRNA 18调节心脏EC功能和心肌细胞存活的机制，在Aim 3中， 将使用MI后小鼠来证明scaRNA 18在心肌损伤修复中的关键作用。拟议 研究可以建立scaRNA作为MI的新治疗靶点。

PROJECT SUMMARY Cardiovascular disease (CVD) remains the leading cause of death, and there is a critical need to determine underlying mechanisms and develop novel therapies for treatment. Small Cajal body-specific RNAs (scaRNAs) are evolutionarily conserved non-coding RNAs that guide biochemical modification on specific nucleotides such as pseudouridylation (Ψ) and 2′-O-ribose methylation (2′-OMe). These modifications are essential in the post- transcriptional changes and functions of spliceosomal small nuclear RNAs (snRNA). Recent studies highlight a crucial role of scaRNA in preserving spliceosome fidelity and cardiac development; however, the role of scaRNAs in acute cardiac injury and its repair has not been established. This proposal aims to determine scaRNA’s role in cardiovascular processes in a mouse myocardial infarction (MI) model that could develop new tools for treating MI. Our central hypothesis is that overexpression of scaRNA18 in the post-MI heart promotes positive cardiac remodeling by inducing therapeutic angiogenesis via 2′-OMe of U4 snRNA and regulating Wilms tumor1 (WT1) expression, thereby conferring cardioprotection and improving cardiac function. Our preliminary data demonstrates 1) decreased scaRNA18 expression in post-MI mouse hearts using unbiased small RNA sequencing, 2) scaRNA18 expression exclusively downregulated in isolated cardiac endothelial cells (EC) in post-MI mouse hearts, 3) scaRNA18 knockdown (KD) impairs tube formation and induces apoptosis in mouse cardiac ECs without induced stress, 4) scaRNA18 overexpression enhances EC angiogenesis and inhibits stress-induced EC apoptosis in vitro, 5) scaRNA18-overexpressing cardiac EC extracellular vesicles protect iPSC-cardiomyocyte cell death via angiogenic proteins, 6) 2’-O-methylation levels were reduced in MI hearts and in cardiac ECs from scaRNA18 KD mice, 7) mutant scaRNA18 lacking binding sites to guide 2′-OMe on U4 snRNA induces EC cell apoptosis without induced stress, 8) unbiased mass spectrometry results revealed that scaRNA18 reduces WT1 expression levels in scaRNA18 KD cardiac ECs, 9) WT-1 KD in the presence of scaRNA18 overexpression nullified scaRNA18 mediated EC survival effects, and 10) overexpression of scaRNA18 by VE-cadherin-driven AAV9 reduces infarct size after ex vivo cardiac ischemia/reperfusion injury and improves cardiac function post-MI mice (in vivo). The hypothesis that scaRNA18 is a critical component in cardiac function and repair will be tested in the following three specific aims: in Aim 1, we will define the role of scaRNA18 in cardiac EC function and cardiomyocyte survival; in Aim 2, we will determine the molecular mechanisms by which scaRNA18 regulates cardiac EC function and cardiomyocyte survival, and in Aim 3 we will use post-MI mice to demonstrate the critical role of scaRNA18 in myocardial injury repair. The proposed studies could establish scaRNAs as novel therapeutic targets for MI.