Wallenberg Laboratory for Cardiovascular Research, Bruna Stråket 16, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden.
Genome Med. 2009 Nov 16;1(11):108. doi: 10.1186/gm108.
A function for the microRNA (miRNA) pathway in vascular development and angiogenesis has been firmly established. miRNAs with selective expression in the vasculature are attractive as possible targets in miRNA-based therapies. However, little is known about the expression of miRNAs in microvessels in vivo. Here, we identified candidate microvascular-selective miRNAs by screening public miRNA expression datasets.
Bioinformatics predictions of microvascular-selective expression were validated with real-time quantitative reverse transcription PCR on purified microvascular fragments from mouse. Pericyte expression was shown with in situ hybridization on tissue sections. Target sites were identified with 3' UTR luciferase assays, and migration was tested in a microfluid chemotaxis chamber.
miR-145, miR-126, miR-24, and miR-23a were selectively expressed in microvascular fragments isolated from a range of tissues. In situ hybridization and analysis of Pdgfb retention motif mutant mice demonstrated predominant expression of miR-145 in pericytes. We identified the Ets transcription factor Friend leukemia virus integration 1 (Fli1) as a miR-145 target, and showed that elevated levels of miR-145 reduced migration of microvascular cells in response to growth factor gradients in vitro.
miR-126, miR-24 and miR-23a are selectively expressed in microvascular endothelial cells in vivo, whereas miR-145 is expressed in pericytes. miR-145 targets the hematopoietic transcription factor Fli1 and blocks migration in response to growth factor gradients. Our findings have implications for vascular disease and provide necessary information for future drug design against miRNAs with selective expression in the microvasculature.
微小 RNA（miRNA）途径在血管发育和血管生成中的作用已得到充分证实。在血管中选择性表达的 miRNAs 作为 miRNA 为基础的治疗方法的潜在靶点具有吸引力。然而，关于 miRNA 在体内微血管中的表达知之甚少。在这里，我们通过筛选公共 miRNA 表达数据集来鉴定候选微血管选择性 miRNA。
通过实时定量逆转录 PCR 对从小鼠中纯化的微血管片段进行生物信息学预测的微血管选择性表达进行验证。通过组织切片上的原位杂交显示周细胞表达。通过 3'UTR 荧光素酶测定鉴定靶位，并在微流体趋化性室中测试迁移。
miR-145、miR-126、miR-24 和 miR-23a 在从小鼠多种组织中分离的微血管片段中选择性表达。原位杂交和分析 Pdgfb 保留基序突变小鼠表明，miR-145 在周细胞中主要表达。我们鉴定出 Ets 转录因子 Friend 白血病病毒整合 1（Fli1）是 miR-145 的靶标，并表明 miR-145 水平升高会减少体外生长因子梯度对微血管细胞迁移的反应。
miR-126、miR-24 和 miR-23a 在体内微血管内皮细胞中选择性表达，而 miR-145 在周细胞中表达。miR-145 靶向造血转录因子 Fli1，并阻断对生长因子梯度的迁移反应。我们的研究结果对血管疾病具有重要意义，并为未来针对在微血管中选择性表达的 miRNA 的药物设计提供了必要的信息。
