Mechanosensitive M7G epitranscriptome in endothelial health and disease

项目摘要 RNA的化学修饰，统称为“表转录组”，最近出现 作为一种新的基因表达分子控制层。大多数的epitranscriptomic研究解决N6- 甲基腺苷（m6 A）的mRNA在人类癌症。内皮细胞mRNA的分子特性 表转录组及其在调节血管功能中的潜在作用仍然是一个主要的知识空白。 最近的研究表明，哺乳动物的mRNA被广泛地化学修饰， 修饰以依赖于细胞类型和细胞状态的方式发生。N6-甲基腺苷（m6 A），最 哺乳动物mRNA中丰富的内部（5'帽外）甲基化，已与关键的生物学活性相关。 例如增殖、发育和干细胞分化的过程。只有少数最近的研究涉及 mRNA m6 A在心肌细胞重塑和内皮激活中的潜在作用。我们最近 发现哺乳动物mRNA中存在一种新的化学修饰，N7-甲基鸟苷（m7 G）。 内皮细胞mRNA中的系统m7 G定位及其在血管病理生理学中的潜在作用是一个新的研究领域。 未开发的领域 血管内皮细胞通过机械转导机制由血流动态调节。 由扰动流动引起的内皮激活导致广泛的血管疾病。粥样硬化 优先发生在内皮被局部扰动血流激活的动脉部位， 单向流动促进内皮健康。目前的动脉粥样硬化治疗主要针对系统性风险 而不是血管系统本身。这强调了确定和 靶向血管内皮中新机械敏感机制。 我们已经产生了非常强有力的数据，表明mRNA m7 G在细胞中受到动态调节， 内皮细胞的血流动力学。单向血流（UF）显著增加内皮细胞中的m7 G，但不增加m6 A。 mRNA。此外，甲基转移酶样7A（Methyltransferase-Like 7A，L7 A）是一种新型的m7 G写入器，其控制UF诱导的细胞凋亡。 内皮中mRNA m7 G甲基化。这个项目的总体目标是描绘新的分子 机械敏感性肌L7 A调控内皮mRNA m7 G和调节血管生成的机制 在体外和体内发挥作用。此外，我们将设计创新的精确纳米医学方法， 胃L7 A介导的治疗动脉粥样硬化的途径。

Project Summary RNA chemical modifications, collectively referred to as the “epitranscriptome”, have recently emerged as a novel layer of molecular control of gene expression. Most epitranscriptomic studies address N6- methyladenosine (m6A) of mRNA in human cancers. The molecular identity of endothelial mRNA epitranscriptome and its potential role in regulating vascular functions remains a major knowledge gap. Recent studies suggested that mammalian mRNAs are broadly chemically modified and mRNA modifications occur in a cell-type and cell-state dependent manner. N6-methyladenosine (m6A), the most abundant internal (outside of the 5’ cap) methylation in mammalian mRNA, has been linked to critical biological processes such as proliferation, development, and stem cell differentiation. Only few recent studies addressed the potential role of mRNA m6A in cardiomyocyte remodeling and endothelial activation. We recently discovered the presence of a new chemical modification, N7-methylguanosine (m7G) in mammalian mRNA. Systematic m7G mapping in endothelial mRNA and its potential role in vascular pathophysiology is an unexplored territory. Vascular endothelium is dynamically regulated by blood flow via mechano-transduction mechanisms. Endothelial activation by disturbed flow contributes to a wide range of vascular diseases. Atherosclerosis preferentially develops in arterial sites where endothelium is activated by local disturbed flow whereas unidirectional flow promotes endothelial health. Current atherosclerosis therapies mainly target systematic risk factors but not the vasculature per se. This underscores the significance and unique opportunity to identify and target novel mechanosensitive mechanisms in vascular endothelium. We have generated very strong data demonstrating that the mRNA m7G is dynamically regulated in endothelium by hemodynamics. Unidirectional flow (UF) markedly increases m7G but not m6A in endothelial mRNAs. Moreover, Methyltransferase-Like 7A (METTL7A) is a novel m7G writer governing the UF-induced mRNA m7G methylation in endothelium. The overall goal of this project is to delineate the novel molecular mechanisms by which mechano-sensitive METTL7A governs endothelial mRNA m7G and regulates vascular functions in vitro and in vivo. Moreover, we will devise innovative precision nanomedicine approaches targeting METTL7A-mediated pathways to treat atherosclerosis.