Role of microRNA-17-92 and PDLIM5 Signaling in Pulmonary Arterial Hypertension

microRNA-17-92 和 PDLIM5 信号传导在肺动脉高压中的作用

• 批准号: 9261587
• 负责人: J. Usha RAJ
• 金额: $ 39.98万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-15 至 2019-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9261587
• 关键词: Arteries; Attenuated; Blood; Blood Vessels; Cells; Chronic; Chronic Phase; Clinical; Complex; Development; Disease; Down-Regulation; E2F1 gene; Etiology; Event; Experimental Models; Failure; Functional disorder; Gene Expression; Genes; Heart; Human; Hypoxia; Hypoxia Inducible Factor; Hypoxia-Inducible Factor Pathway; In Vitro; Knock-out; LIM Domain; Lead; Lung; MicroRNAs; Molecular; Mus; Nature; Oxygen; Pathogenesis; Pathway interactions; Patients; Phase; Phenotype; Play; Procollagen-Proline Dioxygenase; Proteins; Public Health; Pulmonary Hypertension; Pulmonary Vascular Resistance; Pulmonary artery structure; RNA; Regulation; Reporting; Research; Resistance; Role; Severities; Side; Signal Transduction; Smooth Muscle Myocytes; Structure; TP53 gene; Testing; Transforming Growth Factor beta; Untranslated RNA; Up-Regulation; Vascular remodeling; Ventricular; arterial remodeling; design; in vivo; inhibitor/antagonist; insight; mouse model; novel; novel strategies; overexpression; pressure; prevent; primary pulmonary hypertension; protein expression; public health relevance; pulmonary arterial hypertension; reconstitution; response; treatment strategy

 DESCRIPTION (provided by applicant): MicroRNAs (miRNAs) are small non-coding endogenous RNA molecules that are thought to be involved in the pathogenesis of pulmonary arterial hypertension (PAH) though their exact roles are not known. We found that smooth muscle cell (SMC)-specific knockout of miR-17~92 in mice attenuated hypoxia-induced pulmonary hypertension (PH) and reconstitution of miR-17~92 restored it, indicating an important role for miR-17~92 in pathogenesis of PH. We identified that miR-17~92 directly targets prolyl hydroxylase 2 (PHD2) and PDZ and LIM domain 5 (PDLIM5) proteins. Suppression of miR-17~92 induced PHD2 expression and inhibited HIF activity, induced PDLIM5 expression and decreased TGF-ß/Smad signaling and expression of SMC markers, all of which attenuated PH. SMC-specific knockout of PHD2 and PDLIM5 enhanced hypoxia-induced pulmonary artery remodeling whereas overexpression of PDLIM5 inhibited hypoxia-induced PH. These results indicate that miR-17~92 modulates PH by regulating the expression of PHD2 and PDLIM5. In PASMC in-vitro and mouse lungs in-vivo, chronic hypoxia resulted in a biphasic expression of miR-17~92: an early increase followed by a decrease in expression. We found that miR-17~92 expression was reduced in PASMC isolated from PAH patients and that this reduction in miR-17~92 accounted for the de-differentiated phenotype of the IPAH-PASMC. We speculate that up regulation of miR-17~92 may be a common initial event in the pathogenesis of both human and experimental PH and that the late decrease in miR-17~92 expression may be an adaptive mechanism to inhibit further progression of PH. Our hypothesis is that miR-17~92 initiates the pathogenesis of PAH by: 1) directly suppressing PHD2 to activate the HIF pathway; 2) directly suppressing PDLIM5 to activate the TGF-ß/Smad2/3 pathway. The biphasic nature of miR-17~92 expression in chronic hypoxia is a novel finding and we will investigate its significance and the mechanisms involved. In Specific Aim 1, we will determine the molecular mechanisms by which miR-17~92 and PHD2 regulate hypoxia- induced PH. We will investigate whether PHD2 is a novel direct target of miR-17~92 and the molecular mechanisms by which miR-17~92 and PHD2 regulate HIF activity and PH. Specific Aim 2 is to determine the molecular mechanisms by which miR-17~92 and PDLIM5 regulate hypoxia-induced vascular remodeling and PH. We will investigate whether PDLIM5 is a novel direct target of miR-17~92 and the molecular mechanisms by which PDLIM5 negatively regulates TGF-ß/Smad signaling and inhibits the progression of PH. In Specific Aim 3, we will determine the molecular mechanisms underlining the biphasic expression of miR-17~92 and its implication in PH progression. We will investigate the roles of HIF and E2F1 in up regulation of miR-17~92 in the early phase of chronic hypoxia, the role of p53 in inhibition of miR-17~92 in the late phase of chronic hypoxia, and whether knockout of miR-17~92, PHD2, and PDLIM5 in the late stage of hypoxia diminishes or accentuates PH in mice.

 描述(申请人提供)：microRNAs(MiRNAs)是一种小的非编码内源性RNA分子，被认为参与了肺动脉高压(PAH)的发病机制，尽管它们的确切作用尚不清楚。我们发现，在小鼠的缺氧性肺动脉高压中，血管平滑肌细胞(SMC)特异性敲除miR-17~92可减轻缺氧性肺动脉高压(PH)，而miR-17~92的重建可使其恢复，提示miR-17~92在PH发病机制中起重要作用。我们发现miR-17~92直接作用于脯氨酸羟基酶2(PHD2)和PDZ和Lim结构域5(PDLIM5)蛋白。抑制miR-17~92可诱导PHD2表达，抑制HIF活性，诱导PDLIM5表达，减少转化生长因子β/Smad信号转导和SMC标志物的表达，从而减轻PH。SMC特异性敲除PHD2和PDLIM5可增强低氧诱导的肺动脉重构，而过表达PDLIM5则抑制低氧诱导的肺动脉高压。这些结果表明miR-17~92通过调节PHD2和PDLIM5的表达来调节PH。在体外的PASMC和体内的小鼠肺中，慢性低氧导致miR-17~92的表达呈现先升高后降低的双相性。我们发现，从PAH患者分离的PASMC中miR-17~92的表达降低，这种miR-17~92的降低是IPAH-PASMC去分化表型的原因。我们推测miR-17~92的上调可能是人和实验性PH发病机制中共同的初始事件，而miR-17~92表达的后期降低可能是抑制PH进一步进展的适应性机制。我们的假设是miR-17~92通过直接抑制PHD2激活HIF通路，直接抑制PDLIM5激活转化生长因子/Smad2/3通路，从而启动PAH的发病。MiR-17~92在慢性缺氧中表达的双相性是一个新的发现，我们将探讨其意义和相关机制。在特定的目标1中，我们将确定miR-17~92和PHD2调节低氧诱导的PH的分子机制。我们将研究PHD2是否是miR-17~92的一个新的直接靶点，以及miR-17~92和PHD2调节HIF活性和PH的分子机制。具体目的2是确定miR-17~92和PDLIM5调节缺氧诱导的血管重构和PH的分子机制。我们将探讨PDLIM5是否是miR-17~92的一个新的直接靶点，以及PDLIM5负性调节转化生长因子/Smad信号和抑制PH进展的分子机制。在特定的目标3中，我们将确定miR-17~92双相表达的分子机制及其在PH进展中的意义。我们将探讨HIF和E2F1在慢性缺氧早期miR-17~92上调中的作用，p53在慢性缺氧晚期抑制miR-17~92中的作用，以及在慢性缺氧晚期敲除miR-17~92、PHD2和PDLIM5是否降低或加剧小鼠的PH。