Kruppel-like factor 15 regulates BMPER in endothelial cells
Kruppel-like factor 15 regulates BMPER in endothelial cells
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DOI：
10.1093/cvr/cvp314
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发表时间：
2010-02-01
影响因子：
10.8
通讯作者：
Moser, Martin
中科院分区：
文献类型：
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作者：
Helbing, Thomas;Volkmar, Franziska;Moser, Martin
目的骨形态发生蛋白（BMPs）在健康和疾病中参与胚胎和成人血管的形成。已有研究表明，BMP内皮细胞前体衍生调节剂（BMPER）在内皮细胞功能和血管形成中起着重要作用。BMPER是BMP4活性的关键调节因子，是内皮细胞中BMP4激活BMP通路的先决条件。在这里，我们描述了BMPER启动子的特征并阐明了BMPER调控的机制。方法与结果通过克隆小鼠BMPER启动子并对其进行表征，研究BMPER的转录机制。BMPER启动子的一系列50个缺失表明，近端启动子含有活化的顺式元件。通过过表达或基于sirna的敲低，我们证明了BMPER的表达是由kruppel样因子（KLF） 15激活的。gelshift分析表明，KLF15直接与BMPER启动子内2284 bp的预测klf结合元件结合。共表达实验表明Sp1可作为klf15诱导的启动子激活的拮抗剂。内皮素-1被鉴定为内皮细胞中KLF15和BMPER表达的有效抑制剂，表明KLF15是内皮素-1活性对BMPER表达的换能器。选择性ETB内皮素受体拮抗剂BQ788可消除内皮素-1下调BMPER表达的作用。结论在机制上，我们发现KLF15是BMPER表达的强而直接的激活因子。内皮素-1以剂量依赖的方式下调BMPER，并与KLF15平行。由于KLF15缺乏伴随着血管表型，而BMPER是血管形成所必需的，我们认为内皮素-1对BMPER的影响是由KLF15介导的。
Aims Bone morphogenetic proteins (BMPs) are involved in embryonic and adult blood vessel formation in health and disease. Previous studies have shown that BMP endothelial cell precursor-derived regulator (BMPER) plays an important role in endothelial cell function and blood vessel formation. BMPER is a key regulator of BMP4 activity and a prerequisite for BMP pathway activation by BMP4 in endothelial cells. Here, we characterize the BMPER promoter and elucidate mechanisms of BMPER regulation.Methods and results To investigate transcriptional mechanisms of BMPER expression, the murine BMPER promoter was cloned and characterized. A series of 50 deletions of the BMPER promoter revealed that the proximal promoter contains activating cis-elements. By overexpression or siRNA-based knockdown, we demonstrate that BMPER expression is activated by Kruppel-like factor (KLF) 15. As determined by gelshift analyses, KLF15 binds directly to a predicted KLF-binding element at 2284 bp within the BMPER promoter. Co-expression experiments show that Sp1 acts as an antagonist for KLF15-induced promoter activation. Endothelin-1 was identified as a potent inhibitor of KLF15 and BMPER expression in endothelial cells, suggesting that KLF15 is a transducer of endothelin-1 activity on BMPER expression. The selective ETB endothelin receptor antagonist BQ788 abolished the downregulation of BMPER expression by endothelin-1.Conclusion Mechanistically, we found that KLF15 is a strong and direct activator of the BMPER expression. BMPER is downregulated by endothelin-1 in a dose-dependent fashion and in parallel to KLF15. As KLF15 deficiency is accompanied by a vascular phenotype and BMPER is necessary for proper blood vessel formation, we suggest a chain of events in which the effects of endothelin-1 on BMPER are mediated by KLF15.