miR-181b, endothelial cells, and vascular inflammation

血管内皮细胞(EC)的激活和功能障碍与多种慢性血管炎症有关 疾病状态，包括胰岛素抵抗(IR)、肥胖和动脉粥样硬化--发病率和 西方社会的死亡率。促炎症细胞因子和致动脉粥样硬化的危险因子 高脂血症激活核因子-kB和Mekk/JNK等关键信号通路，降低保护性信号通路 例如AKT/eNOS信号，这种作用赋予内皮细胞促黏附和促血栓形成特性。 因此，抑制血管内皮细胞的炎症反应可能提供一种新的 限制IR/肥胖和动脉粥样硬化血栓形成的治疗方法。 MicroRNAs(MiRNAs)是一种小的、单链、非编码的RNA，能够抑制基因的表达 转录后水平，并参与多种病理生理过程，包括 免疫和炎症反应的调节。在此授权期内，我们确定miR-181b为节点 通过对两条主要信号通路--核因子-kB的调节调节内皮细胞的静止 和AKT/eNOS，并发现了治疗的新靶点。初步的和已发表的观察结果 确定内皮miR-181b是全身炎症、肥胖/IR和动脉粥样硬化的关键决定因素。 此外，我们的研究强调了依赖于microRNA的靶标与配体特异性反应的相关性。 ECs中的信号--microRNA领域中的一个新兴概念。此外，我们还证明了甲氨蝶呤 甲氨蝶呤(MTX)是一种临床相关的抑制内皮细胞激活的疗法，可以在miR-181b- 依赖的态度。这些观察结果为中心假设提供了基础，即内皮细胞miR- 181b通过抑制核因子-κB和MEKK/JNK，以及对AKT/eNOS信号的诱导作用来调节 全身性血管炎症、IR/肥胖和动脉粥样硬化。为了更好地理解miR的确切作用- 181b在对EC激活的刺激特异性调控中，提出了三个目标。在Aim1中，我们将描述 MiR-181b抑制内皮细胞NF-κB和MEKK/JNK并诱导AKT/eNOS的分子基础 对不同刺激做出反应的通路。在AIM2中，我们将确定改变内皮细胞miR-181b的效果 肥胖/胰岛素抵抗和动脉粥样硬化血栓形成的表达。在Aim3中，我们将探索分子 甲氨蝶呤(MTX)挽救内皮细胞miR-181b表达的机制，我们将确定 MTX的抗炎作用是否依赖miR-181b。这些研究的结果将 提供关于miR-181b介导的对内皮细胞激活和功能的控制的见解 MiR-181b的充足和缺乏对胰岛素抵抗和动脉粥样硬化的影响。此外， 探索miR-181b和MTX之间联系的研究可能会提供可以利用的见解 治疗范围广泛的慢性炎症性疾病的治疗成果。

Endothelial cell (EC) activation and dysfunction have been linked to a variety of chronic vascular inflammatory disease states including insulin resistance (IR), obesity, and atherosclerosis—the major cause of morbidity and mortality in Western Societies. Proinflammatory cytokines and proatherogenic risk factors such as hyperlipidemia activate key signaling pathways such as NF-kB and MEKK/JNK and decrease protective ones such as AKT/eNOS signaling, an effect that confers pro-adhesive and pro-thrombotic properties to ECs. Therefore, suppressing the inflammatory response in the vascular endothelium may provide a novel therapeutic approach to limit IR/obesity, and atherothrombosis. MicroRNAs (miRNAs) are small, single-stranded, non-coding RNAs capable of repressing gene expression at the post-transcriptional level and are involved in a variety of pathophysiological processes including the regulation of immune and inflammatory responses. During this grant period, we identified miR-181b as a nodal regulator of endothelial cell quiescence through its regulatory effects on two major signaling pathways – NF-kB and AKT/eNOS, and have uncovered novel targets for therapy. Preliminary and published observations now identify endothelial miR-181b as a critical determinant of systemic inflammation, obesity/IR, and atherogenesis. Furthermore, our studies highlight the relevance of microRNA-dependent targets in response to ligand-specific signaling in ECs–an emerging concept in the microRNA field. Moreover, we demonstrate that methotrexate (MTX), a clinically relevant therapy that suppresses endothelial activation, can function in a miR-181b- dependent manner. These observations provide the foundation for the central hypothesis that endothelial miR- 181b, via inhibitory effects on NF-κB and MEKK/JNK and inductive effects on AKT/eNOS signaling, regulates systemic vascular inflammation, IR/obesity, and atherosclerosis. To better understand the precise role of miR- 181b in stimuli-specific regulation of EC activation, three aims are proposed. In Aim1, we will delineate the molecular basis for miR-181b's ability to inhibit endothelial NF-κB and MEKK/JNK and induce AKT/eNOS pathways in response to divergent stimuli. In Aim2, we will determine the effect of altered endothelial miR-181b expression on obesity/insulin resistance and atherothrombosis. In Aim3, we will explore the molecular mechanisms by which methotrexate (MTX) rescues miR-181b expression in ECs, and we will determine whether the anti-inflammatory effects of MTX are miR-181b-dependent. The results of these studies will provide insights regarding miR-181b-mediated control of endothelial activation and the functional consequences of miR-181b sufficiency and deficiency on insulin resistance and atherogenesis. Furthermore, studies exploring the link between miR-181b and MTX may provide insights that can be exploited for therapeutic gain in the treatment of a broad spectrum of chronic inflammatory disorders.