Non-cardiomyocyte miR-34a Mediates Susceptibility to Right Heart Failure

 描述（由申请人提供）：本提案描述了一个为期五年的职业发展计划，以准备候选人Sushma Reddy博士作为一名独立科学家评估右心衰竭的机制。该计划将扩大Reddy博士在心血管研究方面的科学背景，通过重点课程工作，技术培训和有针对性的实习提供心肌，线粒体和内皮生物学方面的技术培训和专业知识。此外，Reddy博士将通过加强批判性思维、沟通、协作、指导和实验室管理方面的技能，成功地从一名受指导的临床科学家转变为一名独立的科学家。 microRNAs（miRs）是一类非编码的小分子RNA，是心脏重塑的重要调控因子。然而，关于它们在右心室肥大（RVH）和衰竭（RVF）中的作用的数据很少。对于许多先天性心脏病患者来说，了解RV重塑的机制是一个关键问题，因为与左心室（LV）相比，后负荷应激的RV更容易失败，并且标准心力衰竭治疗在RVF患者中无效。虽然RV和LV对压力超负荷的分子反应基本相似，但氧化应激和血管生成的调节剂存在关键差异，这可以解释RV的脆弱性增强。 Reddy博士的目的是阐明miR作为这些RV-LV差异机制的作用。使用鼠模型，她鉴定了miR 34 a、28、93和148 a为RVH/RVF所特有。有趣的是，所有四种miR仅在非心肌细胞中表达，但可能在心肌细胞中具有最大的作用。她假设RV特异性非心肌细胞miR-34 a通过与心肌细胞的串扰，是导致抗氧化防御早期失败和RVF中血管生成反应减弱的原因。目的1将评估miR-34 a调控RVH向RVF转变的机制。miR-34 a在成纤维细胞、内皮细胞和心肌细胞中的过表达将评估对ROS产生、抗氧化防御和细胞死亡和血管生成的介质的影响，以及miR-34 a与心肌细胞的串扰机制和外泌体的旁分泌作用。目的2将在她的鼠模型中使用LNA antimiRs评估miR-34 a在拯救RVF中的体内功能意义，使用转录组和RISCome测序鉴定新的靶基因，并鉴定患有RVH/RVF的儿童中疾病进展的血浆生物标志物。未来的研究将评估（i）miR 28、93和148 a单独或联合在RV对心力衰竭易感性中的作用机制;（ii）这些miR在慢性压力超负荷模型中的作用和（iii）验证血浆生物标志物在更大的儿童队列中。 总之，这些研究将有助于开发RV特异性心力衰竭治疗方法，并确定RV衰竭的生物标志物，允许早期医疗或手术干预。

 DESCRIPTION (provided by applicant): This proposal describes a five-year career development program to prepare the candidate, Dr. Sushma Reddy, for a career as an independent scientist evaluating the mechanisms of right heart failure. This program will expand Dr. Reddy's scientific background in cardiovascular research by providing technical training and expertise in myocardial, mitochondrial and endothelial biology through focused course work, technical training and targeted externships. In addition, Dr. Reddy's successful transition from a mentored clinician scientist to an independent scientist will be accomplished by strengthening skills in critical thinking, communication, collaboration, mentorship and laboratory management. MicroRNAs (miRs) are small non-coding RNAs that have emerged as crucial regulators of cardiac remodeling. However, there is minimal data on their role in right ventricular hypertrophy (RVH) and failure (RVF). Understanding the mechanisms of RV remodeling is a critical question for many patients with congenital heart disease, given that the afterload stressed RV is more likely to fail compared to the left ventricle (LV), and that standard heart failure therapies fail o work in patients with RVF. Although the molecular responses of the RV and LV to pressure overload are largely similar, there are key differences in regulators of oxidant stress and angiogenesis which could explain the enhanced vulnerability of the RV. Dr. Reddy's objective is to elucidate the role of miRs as a mechanism for these RV-LV differences. Using a murine model, she has identified miRs 34a, 28, 93 and 148a as unique to RVH/RVF. Of interest, all four miRs are expressed only in non-cardiomyocytes yet may have their greatest effects in cardiomyocytes. She hypothesizes that RV-specific non-cardiomyocyte miR-34a, through crosstalk with cardiomyocytes, is responsible for the early failure of antioxidant defenses and the attenuated angiogenic response in RVF. Aim 1 will evaluate the mechanisms by which miR-34a regulates the transition from RVH to RVF. Overexpression of miR-34a in fibroblasts, endothelial cells and cardiomyocytes will evaluate effects on ROS production, antioxidant defenses, and mediators of cell death and angiogenesis, as well as the mechanism of miR-34a crosstalk with cardiomyocytes and the paracrine role of exosomes. Aim 2 will evaluate the in vivo functional significance of miR-34a using LNA antimiRs to rescue RVF in her murine model, identify novel target genes using transcriptome and RISCome sequencing, and identify plasma biomarkers of disease progression in children with RVH/RVF. Future studies will evaluate (i) the mechanism of action of miRs 28, 93 and 148a, either singly or in concert in the RV susceptibility to heart failure; (ii) the role of these miRs in a model of chronic pressure overload and (iii) validate plasma biomarkers in a larger cohort of children. In summary, these studies will aid in developing RV-specific heart failure therapies and identify biomarkers of RV failure, allowing earlier medical or surgical intervention.