Second Department of Cardiology, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou City, Henan, China.
Clin Hemorheol Microcirc. 2022;82(2):107-124. doi: 10.3233/CH-211259.
Dysfunction of endothelial cells in the arterial vasculature is an essential contributor to the pathogenesis of atherosclerosis. Circular RNAs (circRNAs) exert important regulatory functions in endothelial cell dysfunction. Here, we explored the precise role and mechanism of circ_0050486 in regulating endothelial cell injury induced by oxidized low-density lipoprotein (ox-LDL).
Circ_0050486, microRNA (miR)-182-5p and myeloid differentiation primary response gene 88 (MyD88) were quantified by quantitative real-time PCR or western blot. Cell viability, proliferation and apoptosis were examined by MTS, 5-Ethynyl-2'-Deoxyuridine (EdU), and flow cytometry assays, respectively. Direct relationship between miR-182-5p and circ_0050486 or MYD88 was verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays.
Circ_0050486 was upregulated in atherosclerosis serum and ox-LDL-treated human aortic endothelial cells (HAECs). Silencing of circ_0050486 suppressed HAEC injury induced by ox-LDL. Mechanistically, circ_0050486 targeted miR-182-5p, and the effects of circ_0050486 silencing were partially due to the upregulation of miR-182-5p. MYD88 was a direct target of miR-182-5p, and miR-182-5p-mediated inhibition of MYD88 attenuated ox-LDL-evoked HAEC injury. Circ_0050486 bound to miR-182-5p to regulate MYD88 expression. Additionally, the NF-κB signaling pathway was involved in the regulation of circ_0050486/miR-182-5p/MYD88 axis in ox-LDL-treated HAECs.
Our study identifies the functional role of circ_0050486 in ox-LDL-induced endogenous cell injury and establishes a mechanism of circ_0050486 function by affecting MYD88 through competitively binding to shared miR-182-5p.
动脉血管内皮细胞功能障碍是动脉粥样硬化发病机制的重要贡献者。环状 RNA（circRNA）在内皮细胞功能障碍中发挥重要的调节作用。在这里，我们探讨了 circ_0050486 在调节氧化低密度脂蛋白（ox-LDL）诱导的内皮细胞损伤中的精确作用和机制。
通过定量实时 PCR 或 Western blot 定量检测 circ_0050486、microRNA（miR）-182-5p 和髓样分化初级反应基因 88（MyD88）。通过 MTS、5-乙炔基-2'-脱氧尿苷（EdU）和流式细胞术分别检测细胞活力、增殖和凋亡。通过双荧光素酶报告和 RNA 免疫沉淀（RIP）实验验证 miR-182-5p 与 circ_0050486 或 MYD88 之间的直接关系。
circ_0050486 在动脉粥样硬化血清和 ox-LDL 处理的人主动脉内皮细胞（HAECs）中上调。沉默 circ_0050486 抑制 ox-LDL 诱导的 HAEC 损伤。机制上，circ_0050486 靶向 miR-182-5p，而 circ_0050486 沉默的部分作用是由于 miR-182-5p 的上调。MYD88 是 miR-182-5p 的直接靶标，miR-182-5p 介导的 MYD88 抑制减弱了 ox-LDL 诱导的 HAEC 损伤。circ_0050486 与 miR-182-5p 结合以调节 MYD88 的表达。此外，NF-κB 信号通路参与了 ox-LDL 处理的 HAEC 中 circ_0050486/miR-182-5p/MYD88 轴的调节。
本研究确定了 circ_0050486 在 ox-LDL 诱导的内源性细胞损伤中的功能作用，并通过竞争结合共享的 miR-182-5p 来影响 MYD88，建立了 circ_0050486 功能的机制。
