Role of miR-146a in Abdominal Aortic Aneurysm

miR-146a 在腹主动脉瘤中的作用

• 批准号: 10363829
• 负责人: Venkateswaran Subramanian
• 金额: $ 50.01万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10363829
• 关键词: 3' Untranslated Regions; Abdominal Aortic Aneurysm; Angiotensin II; Aorta; Autoimmunity; Autophagocytosis; Binding; Binding Sites; Bone Marrow Transplantation; Cardiovascular system; Cell Survival; Cells; Clinical; Deubiquitination; Development; Disease; Event; Genes; Goals; Homeostasis; Human; In Situ Hybridization; Inflammation; Inflammatory; Infusion procedures; Knowledge; Leukocytes; Low Density Lipoprotein Receptor; Medial; Mediating; Medical; MicroRNAs; Modeling; Mus; Operative Surgical Procedures; Outcome; Patients; Peptides; Pharmacology; Plasma; Prevalence; Prevention; Process; Protein-Lysine 6-Oxidase; Proteins; Research; Role; Rupture; Smooth Muscle Myocytes; Solid; Stress; TAF1 gene; TATA-Binding Protein Associated Factors; Testing; Therapeutic; Tissues; Transcriptional Activation; Untranslated RNA; Vascular Smooth Muscle; Western Blotting; abdominal aorta; base; beta Aminopropionitrile; experimental study; gene repression; in silico; inhibitor; insight; mimetics; monocyte; mortality; mouse model; new therapeutic target; novel; novel strategies; novel therapeutic intervention; overexpression; peripheral blood; pre-clinical; prevent; small hairpin RNA; therapeutic development; transcriptome sequencing; treatment strategy

Abstract Abdominal aortic aneurysm (AAA) is a permanent dilation of the abdominal aorta with a high mortality greater than 80% after rupture. Aortic vascular smooth muscle cells (SMCs) are pivotal in maintaining aortic structural integrity and function, and SMC-rich aortic medial stability is highly disrupted in AAA. Currently, besides surgical interventions, no alternative therapeutics are available to blunt AAA progression and rupture. Consequently, there is a dire need to identify novel strategies for development of effective, non-surgical therapeutics. MicroRNA-146a (miR-146a), a well-known regulator of inflammation and auto-immunity, is highly expressed in aneurysmal tissue of AAA patients. However, the role of miR-146a in SMC homeostasis and AAA remains to be explored. In preliminary studies, by in-situ hybridization, we observed that miR-146a is upregulated in SMC-rich aortic media of human and mouse AAAs; miR-146a deficiency significantly promoted Angiotensin II (AngII) -induced AAA formation in normolipidemic mice co-administered with Lysyl oxidase inhibitor, β-aminopropionitrile (BAPN); and mimetics-mediated miR-146a overexpression abolished AngII-induced AAAs in both hypercholesterolemic LDLr-/- mice and normolipidemic mice co-infused with BAPN. To elucidate underlying mechanisms, by RNA sequencing, we identified novel targets from miR-146a deficiency experiments: TFIID-31, a TATA binding protein associated factor involved in transcriptional activation and repression, is significantly upregulated; whereas Beclin-1, a gene indispensable for autophagy induction and USP9X, a deubiquitinase critical for Beclin-1 stabilization, are significantly downregulated. Autophagy, a self-regulatory process by which cells digest, and recycle their cytoplasmic materials for energy purposes under stress. Our preliminary study also showed an increased Beclin-1 in mouse AAAs, as observed in human AAAs and Tat-peptide mediated Beclin-1 activation suppressed AngII-induced AAA formation in mice. In addition, miR-146a overexpression significantly suppressed TFIID-31, promoted USP9X and Beclin-1, and ShRNA-mediated silencing of TFIID-31 increased USP9X in cultured aortic SMCs. Based on these observations, we will test our central hypothesis that miR-146a activation protects against AAA formation and progression by promoting Beclin-1-mediated aortic SMC homeostasis. By utilizing our unique mice models generated specifically for these studies, we propose 3 aims. Aim 1 will test our working sub-hypothesis that miR-146a promotes Beclin-1 stability in aortic SMCs via a TFIID-31-USP9X –dependent manner. Aim 2 will test our working sub-hypothesis that miR-146a activation protects against AAA through activation of SMC-Beclin-1-derived autophagy. Aim 3 will determine the effect of miR-146a / Beclin-1 activation on progression of established AAAs. In summary, we will delineate the protective role of Beclin-1 in AAA and establish miR-146a activation as a novel therapeutic strategy against AAA by targeting SMC-Beclin-1. This mechanistic research will set solid preclinical evidence that targeting miR-146a represents a novel therapeutic strategy for treatment and prevention of AAA.

抽象的 腹主动脉瘤（AAA）是腹主动脉的永久词典，死亡率很高 破裂后大于80％。主动脉血管平滑肌细胞（SMC）在维持主动脉方面至关重要 在AAA中，结构完整性和功能以及富含SMC的主动脉内侧稳定性受到高度破坏。现在， 除了手术干预外，没有其他替代治疗可用于钝AAA的进展和破裂。 因此，迫切需要确定开发有效，非手术的新型策略 理论。 MicroRNA-146A（miR-146a）是炎症和自动免疫的众所周知的调节剂 在AAA患者的动脉瘤组织中表达。但是，miR-146a在SMC稳态和 AAA仍有待探索。在初步研究中，通过原位杂交，我们观察到miR-146a是 在人类和小鼠AAA的SMC富含主动脉介质中上调； miR-146a缺乏大量升高 血管紧张素II（AngII）诱导的AAA形成在与氧化物抑制剂共同采用的正常小鼠中 β-氨基异位二硫酸酯（BAPN）;和模拟物介导的miR-146a过表达废除了Angii诱导的AAAS 高胆固醇血症的LDLR - / - 小鼠和与BAPN共同注射的正常脂肪小鼠。阐明基础 机制，通过RNA测序，我们从miR-146a缺乏实验中确定了新靶标：TFIID-31， 与转录激活和表达有关的TATA结合蛋白相关因子，显着 更新；而Beclin-1是一种自噬诱导不可或缺的基因和USP9X，去泛素酶 对于Beclin-1稳定至关重要，显着下调。自噬，一个自我调节过程 哪些细胞消化，并在应力下以能量目的回收其细胞质材料。我们的初步 研究还显示，如在人AAA和TAT肽中观察到的小鼠AAA中的Beclin-1增加 介导的Beclin-1激活抑制了Angii诱导的小鼠AAA形成。此外，mir-146a 过表达显着抑制了TFIID-31，促进了USP9X和Beclin-1，以及ShRNA介导的 TFIID-31的沉默增加了培养的主动脉SMC中USP9X。基于这些观察，我们将测试我们的 miR-146a激活可通过促进保护AAA的形成和进展的中心假设 Beclin-1介导的主动脉SMC稳态。通过使用我们专门生成的独特小鼠模型 这些研究，我们提出了3个目标。 AIM 1将测试我们的工作子疗法，miR-146a促进Beclin-1 通过TFIID-31-USP9X - 依赖性方式在主动脉SMC中的稳定性。 AIM 2将测试我们的工作子假设 MiR-146a激活通过激活SMC-Beclin-1衍生的自噬来预防AAA。目标3 将确定miR-146a / beclin-1激活对已建立AAA的进展的影响。总而言之，我们 将描述Beclin-1在AAA中的受保护作用，并建立miR-146a激活作为一种新的疗法 通过针对SMC-Beclin-1来针对AAA的策略。这项机械研究将为稳定的临床前证据设定 靶向miR-146a代表了治疗和预防AAA的新型治疗策略。