Background: The dysregulation of proliferation and migration of vascular smooth muscle cells (VSMCs) is one of the major causes of atherosclerosis (AS). Accumulating studies confirm that Kruppel-like factor 4 (KLF4) can regulate the proliferation and differentiation of VSMCs through multiple signaling pathways. However, the mechanism of KLF4 dysregulation remains unknown. Methods: Apolipoprotein E-knockout (ApoE^−/−) mice and human VSMCs were used to establish AS animal model and cell model, respectively. qRT-PCR was employed to determine the expressions of miR-506-3p and KLF4. Cell Counting Kit -8, Transwell, TUNEL assays, and flow cytometry were performed to measure the proliferation, migration, and apoptosis of VSMCs. The upstream miRNAs of KLF4 were predicted by microT, miRanda, miRmap, and TargetScan databases. The interaction between KLF4 and miR-506-3p was confirmed using qRT-PCR, Western blot, and luciferase reporter gene assay. Results: KLF4 expression was significantly decreased in the VSMCs of ApoE^−/− mice fed with high-fat diet and in human VSMCs treated with oxidized low-density lipoprotein in time-dependent and dose-dependent manners. The transfection of miR-506-3p mimics or KLF4 shRNA promoted the proliferation and migration of VSMCs but inhibited the apoptosis while miR-506-3p inhibitors and pcDNA3.1-KLF4 exerted opposite effects. Additionally, KLF4 was confirmed as a target gene of miR-506-3p and could be negatively regulated by miR-506-3p. Conclusion: MiR-506-3p can promote the proliferation and migration of VSMCs via targeting KLF4, which can probably contribute to the pathogenesis of AS.
Pathobiology

中文翻译：

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MiR-506-3p 通过靶向 KLF4 促进血管平滑肌细胞的增殖和迁移

背景：血管平滑肌细胞（VSMCs）增殖和迁移的失调是动脉粥样硬化（AS）的主要原因之一。越来越多的研究证实 Kruppel 样因子 4 (KLF4) 可以通过多种信号通路调节 VSMC 的增殖和分化。然而，KLF4 失调的机制仍然未知。方法：载脂蛋白 E 基因敲除 (ApoE ^-/-)小鼠和人VSMCs分别用于建立AS动物模型和细胞模型。qRT-PCR用于确定miR-506-3p和KLF4的表达。进行细胞计数试剂盒 -8、Transwell、TUNEL 测定和流式细胞术以测量 VSMC 的增殖、迁移和凋亡。KLF4 的上游 miRNA 由 microT、miRanda、miRmap 和 TargetScan 数据库预测。KLF4 和 miR-506-3p 之间的相互作用通过 qRT-PCR、Western 印迹和荧光素酶报告基因检测得到证实。结果： ApoE ^-/-的 VSMC 中 KLF4 表达显着降低高脂肪饮食喂养的小鼠和以时间依赖性和剂量依赖性方式用氧化低密度脂蛋白处理的人 VSMC。miR-506-3p模拟物或KLF4 shRNA的转染促进了VSMCs的增殖和迁移，但抑制了细胞凋亡，而miR-506-3p抑制剂和pcDNA3.1-KLF4则发挥了相反的作用。此外，KLF4 被证实是 miR-506-3p 的靶基因，并且可以被 miR-506-3p 负调控。结论： MiR-506-3p可通过靶向KLF4促进VSMCs增殖和迁移，可能参与AS的发病。
病理生物学