Department of Endocrinology, The Affiliated Changzhou No.2 People's Hospital of Nanjing Medical University, No. 68, Gehu Road, Changzhou, 213161, China.
Inflammation. 2021 Jun;44(3):965-973. doi: 10.1007/s10753-020-01391-x. Epub 2021 Feb 10.
Long noncoding RNAs (lncRNAs) have been reported to be implicated in various biological and pathological processes. However, the function and mechanism of XIST in vascular smooth muscle cells (VSMCs) remains unknown. The levels of XIST, miR-599, and TLR4 were tested by RT-qPCR. VSMCs and human mononuclear cells (U937) treated with ox-LDL were used as atherosclerosis (AS) cell models. The CCK-8 assay was adopted to detect cell viability. Cell apoptosis was examined by the TUNEL assay. A dual-luciferase reporter assay was employed to investigate the interaction between miR-599 and XIST or TLR4. In this research, we uncovered that the XIST level was elevated in the serum of AS patients and ox-LDL-treated AS cell models. Functional analysis revealed that XIST depletion restrained cell proliferation, while induced the apoptosis in AS cell models. Besides, miR-599 was verified to be a direct downstream target of XIST and miR-599 inhibitor reversed the effects of XIST knockdown on AS progression. Finally, we demonstrated that XIST increased TLR4 expression by serving as a ceRNA of miR-599. All these findings manifested the role of the XIST/miR-599/TLR4 axis in AS development.
长链非编码 RNA（lncRNAs）已被报道参与各种生物学和病理学过程。然而，XIST 在血管平滑肌细胞（VSMCs）中的功能和机制仍不清楚。通过 RT-qPCR 检测 XIST、miR-599 和 TLR4 的水平。使用 ox-LDL 处理的 VSMCs 和人单核细胞（U937）作为动脉粥样硬化（AS）细胞模型。采用 CCK-8 测定法检测细胞活力。通过 TUNEL 测定法检测细胞凋亡。采用双荧光素酶报告基因检测法研究 miR-599 与 XIST 或 TLR4 之间的相互作用。在这项研究中，我们发现 XIST 在 AS 患者的血清和 ox-LDL 处理的 AS 细胞模型中升高。功能分析表明，XIST 耗竭抑制细胞增殖，同时诱导 AS 细胞模型中的细胞凋亡。此外，miR-599 被证实是 XIST 的直接下游靶标，miR-599 抑制剂逆转了 XIST 敲低对 AS 进展的影响。最后，我们证明 XIST 通过作为 miR-599 的 ceRNA 增加 TLR4 的表达。所有这些发现表明 XIST/miR-599/TLR4 轴在 AS 发展中的作用。
