RNA编辑/修饰关键酶ADAR1调控内皮细胞焦亡介导的免疫炎症所致肺血管损伤的机制研究

免疫炎症在血管稳态失衡与重构异常中发挥关键作用，是动脉粥样硬化、肺动脉高压(PAH)等重大血管疾病的重要发病机制。针对血管疾病炎症反应调控的研究众多，但是鲜有RNA水平的调控机制研究，缺乏对RNA编辑/修饰在血管疾病发生发展中作用的探索，因此影响了对血管免疫稳态失衡与损伤发生机制的全面认识。RNA腺苷脱氨酶1(ADAR1)在RNA编辑/修饰中发挥关键作用。我们前期在PAH研究中发现：1)ADAR1在PAH患者和动物模型中均显著升高；2)ADAR1升高导致肺血管免疫炎症反应和内皮细胞焦亡(Pyroptosis)；3)抑制ADAR1表达上调可逆转肺血管损伤和PAH。本课题将首次系统验证“ADAR1通过内皮细胞焦亡引起免疫炎症稳态失衡而导致肺血管损伤与重构”这一科学假说，推动RNA水平调控血管免疫炎症研究领域的前沿进展，为肺动脉高压及其他相关血管疾病的诊治提供重要靶标。

Inflammatory immune response is a major cause of abnormal vascular homeostasis and pathological vascular remodeling. It is considered as a key mechanism underlying diverse cardiovascular diseases, such as atherosclerosis (AS), coronary artery disease (CAD), and pulmonary arterial hypertension (PAH). Excessive vascular inflammation critically contributes to pulmonary vascular remodeling and injury, a characteristic feature of PAH pathology that ultimately leads to right heart failure and death. As the most inner lining of the vascular wall, the monolayer vascular endothelium is highly susceptible to inflammatory insults, resulting in endothelial cell dysfunction and injury that represent as an earliest event for the development of pathological pulmonary vascular remodeling. Inflammatory activation of endothelial cells manifests in endothelial dysfunction, increased expression of cytokines and chemokines, leukocyte infiltration, and endothelial cell hyperpermeability.. .In recent years, ample studies have revealed multifaceted regulatory mechanisms in inflammatory immune response-induced tissue injury, involving DNA expression, RNA transcription, protein translation and its post-translational modulation, as well as epigenetic regulation. However, how RNA and its editing and/or modulation processes regulate vascular inflammation and injury are poorly understood to date. Hence, this study will focus on the molecular and cellular mechanisms underlying the effects of RNA editing/modulation in inflammation-induced pulmonary vascular remodeling and injury, fulfilling a significant gap of knowledge in this particular area. ..In our preliminary studies, we demonstrate for the first time, that ADAR1 (adenosine deaminase acting on RNA 1), a double-stranded RNA editing enzyme, critically contributes to pulmonary vascular remodeling and animal models of PAH. Specifically, ADAR1 expression was upregulated during PAH development. Silencing ADAR1 significantly decreased right ventricular systolic pressure (RVSP) and right ventricular hypertrophy (RVHI) in PAH. In addition, we observed that GSDM E-mediated pyroptosis, a newly described type of programmed necrotic cell death, was activated in the lung of PAH. Knockdown of GSDM E attenuated PAH development. Intriguingly, ADAR1 positively regulated GSDM E expression. Correlatively, we found increased ADAR1 and GSDM E expression in peripheral blood mononuclear cells (PBMCs) from patients with PAH, providing a direct clinical relevance of ADAR1 and GSDM E in PAH. These experimental observations led to our central hypothesis that ADAR1 participates in PAH development through modulating pulmonary vascular remodeling, at least in part, due to GSDM E-mediated pyroptotic cell death in pulmonary arteries. ..We will test our central hypothesis in the following three specific aims. Specific Aim 1: Assess the role of ADAR1-mediated inflammation in pulmonary vascular remodeling and experimental PAH, using two well-established rodent models of PAH. Specific Aim 2: Determine the mechanism of ADAR1 regulation of GSDM E-mediated endothelial cell pyroptosis in PAH development, with the aid of our primary cultured endothelial cells in vitro as well as endothelial cell-specific ADAR1 knockout mice in vivo. Specific Aim 3: Determine temporal and spatial ADAR1 expression profiles and GSDM E- induced pyroptosis in human PAH, utilizing PBMCs and lung tissues of PAH patients. ..It is anticipated that the planned studies will establish, for the first time, the function of ADAR1 and its regulation of GSDM E-mediated pyroptosis in pulmonary vascular remodeling and PAH. The outcomes of this study not only will provide mechanistic insights into pyroptosis-induced pulmonary vascular remodeling in PAH development, but may also serve as a basis for identifying potential new targets for therapeutic intervention in inflammatory immune response-induced vascular disease.