miR-34a改善大鼠肺动脉高压的细胞外基质过度沉积

miR-34a ameliorates extracellular matrix accumulation in monocrotaline-induced pulmonary arterial hypertension

关键词:  miR-34a  细胞外基质  肺动脉高压  MMP-2  TIMP-2

Key words:  miR-34a  extracellular matrix  pulmonary arterial hypertension  MMP-2  TIMP-2

摘要:

目的 研究证实微小RNA-34a(miR-34a)是一种潜在的肿瘤抑制因子和癌症治疗候选基因。我们之前的动物实验发现，miR-34a在细胞外基质(ECM)过度沉积和肺动脉高压(PAH)发病机制中发挥重要作用，但其潜在的分子机制尚未完全明确，本研究旨在解决这一问题。方法 大鼠腹腔注射野百合碱(MCT)构建PAH模型；尾静脉注射miR-34a agomiR构建miR-34a过表达模型。此外，原代培养的大鼠肺动脉平滑肌细胞(PASMCs)分别转染miR-34a inhibitor、MMP-2 siRNA，明确miR-34a和MMP-2在PASMCs的ECM过度沉积中的作用，并进一步探讨其潜在的分子机制。结果 miR-34a在MCT诱导PAH大鼠的肺组织中表达下调，过表达miR-34a改善MCT诱导PAH大鼠的ECM过度沉积和肺血管重塑。此外，细胞实验发现，抑制miR-34a可增加PASMCs中MMP 2/TIMP 2的比值和I型胶原蛋白的表达；敲除MMP 2可逆转由miR-34a表达减低引起的I型胶原蛋白上调。结论 过表达miR-34a可改善MCT诱导ECM过度沉积和肺血管重塑，提示上调miR-34a表达可能在预防和治疗PAH中具有潜在价值。

Abstract:

ABSTRACT：OBJECTIVE It has been shown that miR-34a is regarded as a potential tumor suppressor and therapeutic candidate in cancers. The role of miR-34a in the pathogenesis of extracellular matrix (ECM) accumulation and pulmonary arterial hypertension (PAH) has been involved in our previous animal experiments, but its underlying molecular mechanism is not yet fully understood. The present study aims to address this issue. METHODS Intraperitoneal injection of monocrotaline (MCT) was given to rats to induce the pulmonary arterial hypertension (PAH) model. miR-34a agomiR was administrated to rats by tail vein injection to establish the miR-34a over-expression model. In addition, miR-34a inhibitor, MMP-2 siRNA was transfected into primary cultured pulmonary arterial smooth muscle cells (PASMCs) respectively to examine the effect of miR-34a or MMP-2 on ECM accumulation in PASMCs and to further explore its underlying molecular mechanisms. RESULTS miR-34a was down-regulated in the lung tissues of MCT induced PAH rats, and miR-34a over-expression ameliorated excessive ECM accumulation and pulmonary vascular remodeling in MCT induced PAH rats. In addition, in vitro study found that inhibition of miR-34a increased the ratio of MMP 2/TIMP 2 and the expression of collagen I in PASMCs; and knockdown of MMP 2 reversed the up-regulation of collagen I protein induced by inhibition of miR-34a in PASMCs. CONCLUSION Over-expression of miR-34a ameliorates ECM accumulation in MCT induced PAH, suggesting that elevating miR-34a expression level might be of potential value in the prevention and treatment of PAH.