Division of Cardiology, Emory University, 1639 Pierce Drive, WMB 319, Atlanta, GA 30322, USA.
Biochem Biophys Res Commun. 2010 Mar 19;393(4):643-8. doi: 10.1016/j.bbrc.2010.02.045. Epub 2010 Feb 12.
Mechanical forces associated with blood flow play an important role in regulating vascular signaling and gene expression in endothelial cells (ECs). MicroRNAs (miRNAs) are a class of noncoding RNAs that posttranscriptionally regulate the expression of genes involved in diverse cell functions, including differentiation, growth, proliferation, and apoptosis. miRNAs are known to have an important role in modulating EC biology, but their expression and functions in cells subjected to shear stress conditions are unknown. We sought to determine the miRNA expression profile in human ECs subjected to unidirectional shear stress and define the role of miR-21 in shear stress-induced changes in EC function. TLDA array and qRT-PCR analysis performed on HUVECs exposed to prolonged unidirectional shear stress (USS, 24h, 15 dynes/cm(2)) identified 13 miRNAs whose expression was significantly upregulated (p<0.05). The miRNA with the greatest change was miR-21; it was increased 5.2-fold (p=0.002) in USS-treated versus control cells. Western analysis demonstrated that PTEN, a known target of miR-21, was downregulated in HUVECs exposed to USS or transfected with pre-miR-21. Importantly, HUVECs overexpressing miR-21 had decreased apoptosis and increased eNOS phosphorylation and nitric oxide (NO()) production. These data demonstrate that shear stress forces regulate the expression of miRNAs in ECs, and that miR-21 influences endothelial biology by decreasing apoptosis and activating the NO() pathway. These studies advance our understanding of the mechanisms by which shear stress forces modulate vascular homeostasis.
与血流相关的机械力在调节血管内皮细胞（ECs）中的信号转导和基因表达方面发挥着重要作用。微小 RNA（miRNA）是一类非编码 RNA，可在后转录水平上调节参与多种细胞功能（包括分化、生长、增殖和凋亡）的基因表达。已知 miRNA 在调节 EC 生物学方面发挥着重要作用，但它们在受到切应力条件的细胞中的表达和功能尚不清楚。我们试图确定在受到单向切应力的人 EC 中的 miRNA 表达谱，并确定 miR-21 在切应力诱导的 EC 功能变化中的作用。对暴露于持续单向切应力（USS，24h，15 dynes/cm(2)）的 HUVECs 进行 TLDA 阵列和 qRT-PCR 分析，鉴定出 13 种 miRNA 的表达显著上调（p<0.05）。表达变化最大的 miRNA 是 miR-21；在 USS 处理的细胞中，其表达增加了 5.2 倍（p=0.002）。Western 分析表明，PTEN，miR-21 的已知靶标，在暴露于 USS 或转染 pre-miR-21 的 HUVECs 中下调。重要的是，过表达 miR-21 的 HUVECs 凋亡减少，eNOS 磷酸化和一氧化氮（NO())生成增加。这些数据表明，切应力调节 ECs 中 miRNA 的表达，miR-21 通过减少细胞凋亡和激活 NO()途径来影响内皮生物学。这些研究增进了我们对切应力调节血管稳态的机制的理解。
