Gonsalves Caryn S, Li Chen, Malik Punam, Tahara Stanley M, Kalra Vijay K
Department of Biochemistry and Molecular Biology, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, U.S.A.
Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, U.S.A.
Biosci Rep. 2015 Oct 12;35(6):e00275. doi: 10.1042/BSR20150190.
Endothelin-1 (ET-1) and plasminogen activator inhibitor-1 (PAI-1) play important roles in pulmonary hypertension (PH) in sickle cell disease (SCD). Our previous studies show higher levels of placenta growth factor (PlGF) in SCD correlate with increased plasma levels of ET-1, PAI-1, and other physiological markers of PH. PlGF-mediated ET-1 and PAI-1 expression occurs via activation of hypoxia-inducible factor-1α (HIF-1α). However, relatively little is understood regarding post-transcriptional regulation of PlGF-mediated expression of ET-1 and PAI-1. Herein, we show PlGF treatment of endothelial cells reduced levels of miR-301a and miR-454 from basal levels. In addition, both miRNAs targeted the 3'-UTRs of ET-1 and PAI-1 mRNAs. These results were corroborated in the mouse model of SCD [Berkeley sickle mice (BK-SS)] and in SCD subjects. Plasma levels of miR-454 in SCD subjects were significantly lower compared with unaffected controls, which correlated with higher plasma levels of both ET-1 and PAI-1. Moreover, lung tissues from BK-SS mice showed significantly reduced levels of pre-miR-301a and concomitantly higher levels of ET-1 and PAI-1. Furthermore, we show that miR-301a/miR-454 located in the spindle and kinetochore-associated protein-2 (SKA2) transcription unit was co-transcriptionally regulated by both HIF-1α and peroxisome proliferator-activated receptor-α (PPAR-α) as demonstrated by SKA2 promoter mutational analysis and ChIP. Finally we show that fenofibrate, a PPAR-α agonist, increased the expression of miR-301a/miR-454 and SKA2 in human microvascular endothelial cell line (HMEC) cells; the former were responsible for reduced expression of ET-1 and PAI-1. Our studies provide a potential therapeutic approach whereby fenofibrate-induced miR-301a/miR-454 expression can ameliorate PH and lung fibrosis by reduction in ET-1 and PAI-1 levels in SCD.
内皮素-1（ET-1）和纤溶酶原激活物抑制剂-1（PAI-1）在镰状细胞病（SCD）所致肺动脉高压（PH）中起重要作用。我们之前的研究表明，SCD中胎盘生长因子（PlGF）水平升高与ET-1、PAI-1血浆水平升高以及其他PH生理标志物相关。PlGF介导的ET-1和PAI-1表达通过缺氧诱导因子-1α（HIF-1α）的激活而发生。然而，关于PlGF介导的ET-1和PAI-1表达的转录后调控，人们了解相对较少。在此，我们表明用PlGF处理内皮细胞可使miR-301a和miR-454水平从基础水平降低。此外，这两种微小RNA（miRNA）均靶向ET-1和PAI-1 mRNA的3'非翻译区（3'-UTR）。这些结果在SCD小鼠模型[伯克利镰状小鼠（BK-SS）]和SCD受试者中得到了证实。与未受影响的对照组相比，SCD受试者的血浆miR-454水平显著降低，这与ET-1和PAI-1的较高血浆水平相关。此外，BK-SS小鼠的肺组织显示前体miR-301a水平显著降低，同时ET-1和PAI-1水平较高。此外，我们表明位于纺锤体和动粒相关蛋白2（SKA2）转录单元中的miR-301a/miR-454受HIF-1α和过氧化物酶体增殖物激活受体-α（PPAR-α）共同转录调控，SKA2启动子突变分析和染色质免疫沉淀（ChIP）证明了这一点。最后，我们表明PPAR-α激动剂非诺贝特可增加人微血管内皮细胞系（HMEC）细胞中miR-301a/miR-454和SKA2的表达；前者导致ET-1和PAI-1表达降低。我们的研究提供了一种潜在的治疗方法，即非诺贝特诱导的miR-301a/miR-454表达可通过降低SCD中ET-1和PAI-1水平来改善PH和肺纤维化。
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