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）是腹主动脉的永久性扩张，死亡率很高 主动脉血管平滑肌细胞 (SMC) 在破裂后的存活率超过 80%，对于维持主动脉功能至关重要。 目前，AAA 的结构完整性和功能以及富含 SMC 的主动脉内侧稳定性受到严重破坏。 除了手术干预外，没有其他疗法可以阻止 AAA 的进展和破裂。 经过测试，迫切需要确定新的策略来开发有效的、非手术的 MicroRNA-146a (miR-146a) 是一种众所周知的炎症和自身免疫调节因子。 然而，miR-146a 在 AAA 患者的动脉瘤组织中表达。 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 人类和小鼠 AAA 富含 SMC 的主动脉中膜上调；miR-146a 缺陷显着促进 血管紧张素 II (AngII) 在与赖氨酰氧化酶抑制剂共同给药的正常血脂小鼠中诱导 AAA 形成， β-氨基丙腈 (BAPN)；模拟物介导的 miR-146a 过表达消除了 AngII 诱导的 AAA 高胆固醇血症 LDLr-/- 小鼠和正常血脂小鼠均注射 BAPN。 通过 RNA 测序，我们从 miR-146a 缺陷实验中确定了新的靶点：TFIID-31、 参与转录激活和抑制的 TATA 结合蛋白相关因子，显着 上调；而 Beclin-1（一种自噬诱导不可或缺的基因）和 USP9X（一种去泛素酶） 对 Beclin-1 稳定至关重要的自噬（一种自我调节过程）被显着下调。 我们的初步研究表明，细胞在压力下会消化并回收其细胞质物质以获取能量。 研究还表明，小鼠 AAA 中的 Beclin-1 增加，正如在人类 AAA 和 Tat 肽中观察到的那样 此外，miR-146a 介导的 Beclin-1 激活抑制了 AngII 诱导的 AAA 形成。 过表达显着抑制 TFIID-31、促进 USP9X 和 Beclin-1 以及 ShRNA 介导的 TFIID-31 沉默会增加培养的主动脉 SMC 中的 USP9X。根据这些观察结果，我们将测试我们的结果。 中心假设是，miR-146a 激活通过促进 AAA 的形成和进展来防止 AAA 的形成和进展。 Beclin-1 介导的主动脉 SMC 稳态通过利用我们专门生成的独特小鼠模型。 在这些研究中，我们提出了 3 个目标，目标 1 将测试我们的工作子假设，即 miR-146a 促进 Beclin-1。 通过 TFIID-31-USP9X 依赖的方式提高主动脉 SMC 的稳定性 目标 2 将测试我们的工作子假设。 miR-146a 激活可通过激活 SMC-Beclin-1 衍生的自噬来预防 AAA。 将确定 miR-146a / Beclin-1 激活对已建立的 AAA 进展的影响。 将描述 Beclin-1 在 AAA 中的保护作用，并将 miR-146a 激活确立为一种新型治疗方法 通过针对 SMC-Beclin-1 来对抗 AAA 的策略 这项机制研究将提供可靠的临床前证据。 靶向 miR-146a 代表了一种治疗和预防 AAA 的新治疗策略。