Role of RNAs in post-stroke brain damage

脑缺血显著改变转录和翻译的表达和/或功能 机制包括各种类型的非编码RNA、表观遗传学和表观转录组学。我的 过去20年的研究对这些机制进行了评估，这些机制在促进 中风后的继发性脑损伤或恢复，目标是设计新的治疗方法。在过去的7年里， 我将重点研究各种RNA在促进中风后脑损伤中的作用。我们的目标是 了解其发病机制，并寻找新的治疗靶点，以最大限度地减少继发性 能损伤大脑，促进中风后功能恢复。在这个R35中，我提出了4个项目。项目 1：在目前资助的RO1赠款中，我们正在评估表观遗传学的功能意义 这种修饰被称为DNA羟甲基化(5hmC)。到目前为止，我们的研究表明中风会导致 在许多生存基因中诱导5hmC，诱导它们的表达。我们有趣地观察到 卒中后诱导的许多lncRNA也表现为5hmC水平升高。在这个项目中，我们将 继续研究以了解lncRNAs中5hmC诱导对卒中后的意义 功能结果。项目2：RNA可以通过&gt；150种不同的化学修饰来标记， 共同定义为表位转录修饰，形成额外的一层后- 转录基因调控。其中，N6位的腺苷甲基化(N6- 甲基腺苷(M6A)是大脑中含量最丰富的修饰。我们的研究表明，焦点 缺血下调m6A去甲基酶FTO导致m6A标记的丰度增加 MRNAs。其中许多是炎症性和凋亡性的。此外，FTO的激活促进了RNA 去甲基化和神经保护。我们将使用分子工具来评估其功能意义 以及中风后脑损伤中RNAs m6A甲基化增加的机制。项目3：RNA 也可以进行糖基化的表位转录修饰和神经糖RNA的相互作用 使用小胶质细胞Siglec受体来抑制中枢神经系统损伤后的炎症。我们会研究 脑内糖核糖核酸的意义及其作用机制。项目4：各种班级 的RNA在它们的行动中进行合作。我们特别观察到环状RNA与lncRNA相互作用 来调节mRNAs和microRNAs。我们将分析RNA网络在脑缺血中的作用 脑损伤2例。项目4A：第一个是CircRNA(CircPUM1)的相互作用 用lncRNA(NORAD)控制编码RNA结合蛋白(Pum1)的mRNA和mRNA 它的代码是BNIP2。项目4B：正在进行的RO1正在研究miR-7在控制-突触核蛋白中的作用 在中风后的大脑中。尽管中风后成熟的miR-7水平下降，但Premir-7a和7b的水平 是不会改变的。随着CircRNA CDR1as结合并稳定miR-7，我们计划研究 CDR1as-miR-7--突触核蛋白在介导脑缺血后损伤中的作用总体而言，以上 所有项目都专注于评估各种RNAs的重要性，目标是找到新的 机制和新的目标，以设计未来的分子疗法，以减少中风后的脑损伤。

Cerebral ischemia significantly alters the expression and/or function of transcriptional and translational mechanisms including various classes of noncoding RNAs, epigenetics and epitranscriptomics. My research in the past 20 years evaluated these mechanisms that are central in promoting either secondary brain damage or recovery after stroke with a goal to design novel therapies. In the 7 years, I will focus on studying the role of various RNAs in promoting post-stroke brain damage. The goal is to understand the mechanisms as well as identifying new therapeutic targets to minimize the secondary brain damage and to promote functional recovery after stroke. In this R35, I propose 4 projects. Project 1: In a currently funded RO1 grant we are evaluating the functional significance of an epigenetic modification called DNA hydroxymethylation (5hmC). Our studies so far showed that stroke leads to induction of 5hmC in many prosurvival genes that induces their expression. We intriguingly observed that many lncRNA induced after stroke also show increased 5hmC levels. In this project, we will continue the studies to understand the significance of 5hmC induction in lncRNAs to post-stroke functional outcomes. Project 2: RNAs can be tagged by >150 distinct chemical modifications, which are collectively defined as epitranscriptomic modifications that form an additional layer of post- transcriptional gene regulation. Among them, methylation of the adenosine at N6-position (N6- methyladenosine; m6A) is the most abundant modification in the brain. Our studies show that focal ischemia downregulates m6A demethylase FTO leading to increased abundance of m6A-tagged mRNAs. Many of these are inflammatory and apoptotic. Furthermore, activation of FTO promotes RNA demethylation and neuroprotection. We will use molecular tools to evaluate the functional significance and mechanisms of increased m6A methylation of RNAs in brain damage after stroke. Project 3: RNAs can also undergo the epitranscriptomics modification of glycation and the neural glycoRNAs interact with microglial Siglec receptors to dampen inflammation following CNS insults. We will study the significance of glycoRNAs and the mechanism of action in brain after stroke. Project 4: Various classes of RNAs collaborate in their actions. We particularly observed that circular RNAs interact with lncRNAs to modulate mRNAs and microRNAs. We will analyze the role of RNA networks in relation to ischemic brain damage using 2 examples. Project 4A: The first one is the interaction of a circRNA (circPUM1) with a lncRNA (NORAD) to control a mRNA that codes an RNA binding protein (Pum1) and a mRNA that codes BNIP2. Project 4B: An ongoing RO1 is studying the role of miR-7 in controlling -Synuclein in post-stroke brain. Although mature miR-7 levels decrease after stroke, levels of premiR-7a and 7b are not altered. As circRNA CDR1as binds and stabilizes miR-7, we are planning to study the interactive role of this CDR1as-miR-7--Synuclein in mediating post-ischemic brain damage. Overall, the above projects are all focused to evaluate the significance of various RNAs with a goal to find new mechanisms and new targets to design future molecular therapies to curtail post-stroke brain damage.