Role of microRNA-98 in Myocardial Ischemia Reperfusion Injury in Late Pregnancy

项目摘要 怀孕期间心脏病发作的患病率，也称为心肌梗死(MI)，在过去的几年里有所增加 过去几十年，部分原因是产妇年龄的增加和生活方式的变化。妊娠晚期的MI会带来更严重的 原因不明的非妊娠(NP)妇女预后较差。晚孕(LP)啮齿动物更容易 对心肌缺血再灌注损伤(IRI)与NP啮齿类动物进行比较。此外，活性氧物种 在受IRI影响的LP小鼠中，心脏(ROS)的产生更高。然而，潜在的分子 妊娠晚期对IRI易感性较高的机制尚不清楚。MicroRNAs(MiR)具有 作为一种强大的新型基因表达调节器而出现。在心脏中，几个MIR参与了IRI， 提示调节它们的功能可以作为一种新的心脏保护策略。微RNA 基因芯片分析表明，在扁平苔藓中，microRNA-98-5p(MiR98)的表达显著增加 基线时心脏与NP心脏的比较。令人惊讶的是，与LP相比，miR98在LP心脏中进一步增加 当受到IRI时，对NP心脏的影响。这些miR98表达动态可能是更高的脆弱性的基础 以及LP心脏对IRI的易感性。孕妇的血浆中miR98也显著升高。 与健康的孕妇和健康的非孕妇相比，心血管疾病的风险更高 在生殖年龄。体外数据显示，miR98在女性心肌细胞中的表达增加 受到低氧/复氧的影响，这模拟了IRI。MiR98基因敲除可减少细胞凋亡，ROS 雌性心肌细胞缺氧/复氧后产生炎性标志物的研究 对于miR98的作用，使用TargetScan软件预测miR98靶点。STAT3和pGC-1α表达较强 预测为miR98目标。STAT3和pGC-1α是已知的活性氧负性调节剂 在活体心肌细胞中产生和删除它们被证明使小鼠易患围产期 心肌病。LP大鼠心脏I/R损伤后STAT3和PGC-1α表达降低 与NP组比较，大鼠心脏I/R损伤明显。此外，miR98在体外的敲除增加 STAT3和PGC-1α蛋白的表达，而miR98的过表达降低了它们的表达，提示 他们可能是miR98的目标。这一建议的假设是：i)在LP中诱导miR98导致更高的 靶向STAT3和PGC-1α导致心肌细胞死亡增加的心肌缺血再灌注易感性 Ii)miR98有可能作为一种治疗手段和作为一种 妊娠期心血管疾病早期预测的生物标志物。

Project Summary The prevalence of heart attack, also known as myocardial infarction (MI), in pregnancy has increased over the past decades due in part to rising maternal age and lifestyle changes. MI during late pregnancy carries a worse prognosis than in non-pregnant (NP) women for unclear reasons. The late-pregnant (LP) rodent is more prone to myocardial ischemia-reperfusion injury (IRI) compared to the NP rodent. Furthermore, reactive oxygen species (ROS) production in the heart is higher in LP mice subjected to IRI. However, the underlying molecular mechanisms involved in the higher susceptibility of late pregnancy to IRI are not clear. MicroRNAs (miRs) have emerged as a powerful novel regulator of gene expression. In the heart, several miRs have been involved in IRI, suggesting that regulation of their function could be used as a novel cardioprotective strategy. MicroRNA microarray analysis showed that the expression of microRNA-98-5p (miR98) was highly increased in the LP heart compared to the NP heart at baseline. Strikingly, miR98 was increased further in the LP heart compared to the NP heart when subjected to IRI. These miR98 expression dynamics may underlie the higher vulnerability and predisposition of the LP heart to IRI. miR98 is also significantly increased in the plasma of pregnant women at high risk of cardiovascular disease compared to healthy pregnant patients and healthy non-pregnant patients in the reproductive age. In vitro data shows that the expression of miR98 is increased in female cardiomyocytes subjected to hypoxia/reoxygenation, which mimics IRI. Knockdown of miR98 reduces apoptosis, ROS production, and inflammatory markers in female cardiomyocytes subjected to H/R. To investigate the mechanism of action of miR98, TargetScan software was used to predict miR98 targets. STAT3 and PGC-1α were strongly predicted as miR98 targets. STAT3 and PGC-1α are known negative regulators of reactive oxygen species production and their deletion in cardiomyocytes in vivo has been shown to predispose mice to peripartum cardiomyopathy. Expression of STAT3 and PGC-1α are lower in the LP rat hearts subjected to I/R injury compared to the NP rat hearts subjected to I/R injury. Furthermore, knockdown of miR98 in vitro increases STAT3 and PGC-1α protein expression, whereas miR98 overexpression reduces their expression, suggesting they could be targets of miR98. The hypotheses of this proposal are, i) induction of miR98 in LP leads to higher cardiac vulnerability to IRI via targeting STAT3 and PGC-1α, leading to increased cardiomyocyte death, ROS production, and inflammation, and ii) miR98 has the potential to be served as a therapeutic modality and as a biomarker for early prediction of cardiovascular disease in pregnancy.