Role of miR193 in oxidized lipid induced pulmonary hypertension

 描述(申请人提供)：肺动脉高压(PAH)是一种不可治愈的慢性肺部疾病，其特征是肺动脉压力进行性增加导致右室(RV)心力衰竭。PAH与炎症和肺血管内皮细胞过度增殖有关，导致严重的肺血管重塑。有趣的是，与动脉粥样硬化等其他炎症性疾病一样，研究发现，在PAH患者和伴有肺动脉高压(PH)的缺氧性大鼠的肺中，氧化脂肪酸(如羟基二十碳四烯酸(HETES)和羟基十八碳二烯酸(HODES))的水平上调。我们最近发现，在PAH患者和PH大鼠的血浆中，HETEs和Hodes的水平也显著升高。我们还发现，miR193是一种针对脂氧合酶(LOX)酶的miRNA，参与氧化脂肪酸的产生，在PAH患者的肺和血浆中以及两种实验性的PH动物模型中显著下调。MiR193在肺中的过表达拯救了先前存在的大鼠和小鼠的PH，突出了miR193在逆转肺血管重构方面的治疗作用。为了进一步研究氧化脂肪酸在PH发生发展中的作用，我们将野生型小鼠置于15-HETE饮食中3周，我们发现含有15-HETE足以引发PH。我们推测HETE和HODES可能在PH中起因果作用。我们在15-HETE饮食的小鼠肺中的初步结果还显示：i)miR193的水平显著降低；ii)ED1阳性的炎性巨噬细胞/单核细胞增加；iii)作为miR193靶标的白细胞介素17受体D(IL17-RD)的表达显著增加。这一建议包括三个方面：i)检验仅通过15HETE饮食就足以通过转录因子RXR-a调节miR193及其靶点，从而在WT小鼠中诱导PH的假说的机械臂；ii)确定血浆氧化脂肪酸和miR193是否可作为PAH的生物标志物的诊断臂；以及iii)治疗臂，研究miR193在逆转PAH患者不利血管重构中的作用。目的1将确定RXRmiR193/miR193/LOX通路在15-HETE饮食诱导的PH发生中的作用；Aim 2将确定miR193靶标IL-17RD和IGFR在15-HETE诱导的PH发生中的作用；Aim 3将研究氧化脂肪酸和miR193在肺动脉高压患者中的临床相关性。这项提议将首次提供关于促炎性氧化脂肪酸和miR193的作用的关键信息 调节其在肺动脉高压的调节和发展中的水平。

 DESCRIPTION (provided by applicant): Pulmonary arterial hypertension (PAH) is a non-curable chronic lung disease characterized by progressive increase in pulmonary arterial pressure leading to right ventricular (RV) heart failure. PAH is associated with inflammation and excessive proliferation of pulmonary artery smooth muscle cells and endothelial cells leading to severe pulmonary vascular remodeling. Interestingly, like in other inflammatory diseases such as atherosclerosis, it has been found that the levels of oxidized fatty acids such as hydroxyeicosatetraenoic acids (HETEs) and hydroxyoctadecadienoic acids (HODEs) are upregulated in the lungs from patients with PAH as well as in hypoxic rats with pulmonary hypertension (PH). We recently discovered that the levels of HETEs and HODEs are also robustly elevated in the plasma of PAH patients and in rats with PH. We also discovered that miR193, a miRNA which targets lipoxygenase (LOX) enzymes involved in the production of oxidized fatty acids, is significantly downregulated in the lungs and plasma of PAH patients and in two experimental animal models of PH. Overexpression of miR193 in the lungs rescued pre-existing PH in rats and mice highlighting the therapeutic role of miR193 in reversing pulmonary vascular remodeling. To further examine the role of oxidized fatty acids in development of PH, we placed wild type mice on 15-HETE diet for 3 weeks and we found that 15- HETE containing is sufficient to trigger PH. We hypothesize that HETEs and HODEs may play a causal role in PH. Our preliminary results in the lungs of mice on 15-HETE diet also show: i) levels of miR193 were significantly reduced; ii) ED1-positive inflammatory macrophage/monocytes were increased; and iii) expression of interlukin-17 receptor D (IL17-RD), which is a target of miR193, is significantly increased. This proposal has three arms: i) Mechanistic arm to test the hypothesis that 15HETE diet alone is sufficient to induce PH in WT mice by regulating miR193 and its targets through transcription factor RXR-a; ii) Diagnostic arm to determine whether plasma oxidized fatty acids together with miR193 could serve as biomarker panel for PAH; and iii) Therapeutic arm to examine the role of miR193 for reversal of adverse vascular remodeling in PAH patients. Aim 1 will determine the role of RXRα/miR193/LOX pathway in development of PH induced by 15-HETE diet; Aim 2 will determine the role of miR193 targets IL-17RD and IGFR1 in development of PH induced by 15-HETE diet; and Aim 3 will examine the clinical relevance of oxidized fatty acids and miR193 in PAH patients. This proposal will provide for the first time pivotal information on the role of pro-inflammatory oxidized fatty acids and miR193 that modulate their levels in the regulation and development of pulmonary hypertension.