ADAR1 在血管内皮细胞中作用及其机制的研究

This proposal is to define the function and mechanism of a novel molecule, adenosine deaminase acting on RNA1 (ADAR1) in endothelial cells. Integrity of endothelial cells is essential for normal blood circulation and angiogenesis, and malfunction of this cell leads to diseases of high incidences, such as hypertension, atericlorosis, diabetic vessel pathologic changes. .ADAR1 is an essential protein for posttranscriptional RNA process. it regulates gene functions through changes the protein coden and modifies microRNA biogenesis. It also regulates cytoplasmic RNA signaling pathways to suppress innate immune and stress responses. Our recent study found that ADAR1 plays an critical role in endothelial cells. Specifically knockout ADAR1 in endothelial cells dramatically elevated blood pressure, significantly delayed angiogenesis in hind limb ischemic animal models. We hypothesize that ADAR1 plays an important role in the pathogenesis of blood vessel diseases..In this proposed study, we will analyze the newly generated endothelial specific knockout mice of ADAR1. Using the hind limb ischemic mouse model to look into the function of ADAR1 in angiogenesis. Based on our preliminary finding that coviolin-1 is regulated by ADAR1, we will try to reveal the mechanism of ADAR1 by which it regulate blood vessel function and involves in blood vessel diseases..Through this study, we will better understand the regulation of angiogenesis and pathogenesis of diseases of blood vessel abnormalities. It will likely lay a foundation for development of new therapies for related human diseases.

基于一系列基因敲除动物模型的研究，我们首先发现了RNA腺苷脱氨酶（ADAR1）在血管发生及生长过程中具有重要的作用，但受限于技术及材料的限制，直至最近我们又成功制备了血管内皮细胞特异的ADAR1基因敲除小鼠模型，才使得这一研究得以取得进展。早在全身基因敲除小鼠胚胎中我们已观察到ADAR1缺失时血管发育显著缺陷以致于胚胎不能存活。而血管内皮细胞特异的ADAR1敲除小鼠虽可存活至成年，但新生鼠存活率显著下降并伴有肺结构及功能的显著改变，如血管通透性增加，间质水肿、出血等。在本课题中我们将首先系统观察肺血管结构及分子水平的变化，也将以后肢缺血模型来研究ADAR1在血管再生重建中的作用。着重研究ADAR1在 内皮细胞中的功能及其分子作用机制，对RNA编译及非编译活性，microRNA修饰活性，mRNA转录、翻译调控活性，以及非特异免疫的炎症信号通路调控活性进行系统的观察和比较。

血管内皮的新生功能在疾病的生理病理过程中均发挥重要作用。本研究首次发现ADAR1在血管内皮损伤修复中的重要调控作用。内皮特异性ADAR1缺失小鼠的后肢缺血后血管新生及胚胎血管生成均受损。我们成功的建立的ADAR1 内皮特异性敲除小鼠模型和ADAR1 编译功能缺失基因敲入小鼠，本课题阐明了ADAR1是血管内皮功能的重要调控分子，将为临床血管内皮功能相关疾病的病理机制和临床治疗研究开辟新的方向。研究同时发现组织蛋白酶 L/V（cathepsin L/V, CTSL/V）介导高血压所致的血管重构和介入治疗后的血管重构，发现CTSL/V通过调控平滑肌细胞的MAPK信号通路促进血管重构。发现已经FDA批准的蛋白酶抑制剂沙奎那韦（Saquinavir，SQV）通过抑制CTSL/V活性，并进行了沙奎那韦改善特发性肺动脉高压患者循环炎症指标的临床药物试验，前期结果显示沙奎那韦可有效降低肺动脉高压患者循环中部分炎症分子的水平。为开拓改善血管重构相关药物提供重要的理论基础及依据。