miR-143调节宫外生长发育迟缓致成年期肺动脉高压机制研究

Extrauterine growth retardation (EUGR) refers to severe nutritional deficits during the first weeks of life in human that result in growth that is less than expected based on intrauterine growth rates (growth values ≤10th percentile of intrauterine growth expected in accordance with the estimated gestational age). Early postnatal nutrition is a vital determinant of adult health, the overall incidence of EUGR was 57% assessed by weight in the infant born prematurely and cared for in neonatal intensive care unit.Reduced endothelium- derived NO production in pulmonary arterial vessels has been implicated in the pathophysiology of hypertension. Our results showed the contribution of postnatal undernourishment to long-term lung development, particularly pulmonary arterial hypertension (PAH) in adulthood. Comparing with the control, the 9-week EUGR rats increased the systolic pulmonary artery pressure and decreased of eNOS expression in pulmonary vascular endothelial cell (PVEC). Our study had chosen miR-143 which is the most obvious down-regulation in MicroRNAs Array screen from the PVEC in the 9-week EUGR rat. The most of miR-143/145 cluster studies focus on vascular smooth muscle cell phenotypes in normal tissue and in pulmonary diseases. However, we interested in the effect of miR-143 in PVEC is not as well defined in the pulmonary vasculature diseases. The goal of our study is to explain what is known about the developmental origins of lung disease, how miR-143 contributions to pulmonary vasculature diseases in PVEC and the relationship between eNOS and miR-143 are to be further confirmed. The mechanism which postnatal nutrition affects long-term outcome is whether via posttranscriptional gene silencing/active by miR-143- mediated eNOS mRNA degradation and translational blockade that needs further investigation. Several methods have been used to prove our hypothesis such as establishment of EUGR model in rat, PVECs were isolated by MACS, and miR-143 knockout mouse model, constructing adenovirus vector to infect cells and MicroRNAs Array screen. The results of our proposed investigations will fill vital gaps in our knowledge and provide the molecular and cellular basis for perinatal nutritional perturbations causing permanent changes in pulmonary vasculature disease.

我国每年1600多万新生儿出生，早产的比例已超过8%。宫外生长发育迟缓(EUGR)在早产儿中发生率高达57%。研究及流行病学调查显示EUGR可在成年期引起肺部疾病。我们实验发现EUGR动物模型在成年期PAH发生率增加，PVEC中eNOS表达降低，且miR-143表达量显著下调。本研究集中在肺动脉高压(PAH)的经典途径-NO调控机制，重点为肺血管内皮细胞（PVEC）一氧化氮合酶（NOS）相关基因的表达调控。为明确miR-143参与调控EUGR引起的成年期PAH中靶基因表达改变，探索阐明miR-143参与eNOS的表达的调控途径及分子机制，本项目建立EUGR模型，采用免疫磁珠分选PEVC、RNAi和Knockout小鼠模型等技术。本课题是对EUGR引起的成年期PAH机制的新探索，其结果将有助于阐明EUGR造成PAH的具体机制，并为PAH的治疗靶点提供新的见解。

研究背景：宫外生长迟缓（EUGR）的个体在成年期对低氧的反应性及发生肺动脉高压的风险增加。前期发现新生儿肺动脉高压可能受表观遗传调控。研究方向：探索EUGR引起肺高压相关基因的表观遗传修饰改变，以及早期干预是否可降低成年期肺高压发生的风险。主要内容：按课题计划要求，从体内、体外水平对宫外生长迟缓（EUGR）引起的成年期肺动脉高压及低氧反应性的表观调控机制进行深入研究。（1）在宫外生长迟缓（EUGR）模型中，表观遗传调控可能是肺血管内皮细胞中的eNOS基因表达改变的机制之一。EUGR导致的肺血管功能失调与DNA甲基化和组蛋白异常修饰有关。表观遗传调控的改变存在性别的差异。（2）在EUGR模型中，生后早期肺血管发育受限及成年期肺动脉压增高与肺血管内皮细胞中Notch1表达下降密切相关，并且Notch1基因启动子区组蛋白修饰及DNA甲基化发生改变可能是其表达下降的潜在机制，这些修饰可持续到成年期。（3）在宫内生长迟缓（IUGR）模型中，成年期缺氧诱导的肺动脉高压（PAH）与ET-1基因核心启动子区增加的组蛋白乙酰化程度和转录因子HIF-1α的密集程度密切相关。表观遗传调控可能是IUGR诱导的肺动脉高压的发病机制之一。（4）IUGR成年期发生严重的缺氧性肺动脉高压与PASMCs Kv1.5通道蛋白的表达和功能改变密切相关，Kv1.5通道蛋白的表达升高可以抑制缺氧引起IUGR大鼠原代肺动脉平滑肌细胞增殖的效应。关键数据：共培养研究生12名，其中博士生9名（已毕业4名），硕士生3名（已毕业2名）。科研成果已总结撰文，以标注形式发表中文综述1篇，发表SCI收录论文6篇。科学意义: 本研究对解释胎儿起源的成人疾病的表观调控机制，以及早期适当干预可降低生命后期发生肺动脉高压的风险具有重要意义。可望为成年期的肺动脉高压治疗提供新的思路，并为胎儿起源的成人疾病提供新的理论依据，有重要的临床意义。