Ultrasound-mediated modulation of microRNAs for treatment of cardiac hypertrophy

描述（由申请人提供）：左心室肥大（LVH），如发生在高血压中，会增加心血管事件的风险。临床证据表明LVH的抑制和消退与心脏功能改善和心血管并发症风险降低相关。microRNA（miRNAs）是一类能够调控多个基因的短内源性RNA。miRNA水平已被证明在患病的人类心脏中显着变化。调节miRNA以治疗心血管疾病被视为潜在的强大的临床工具;例如，在高血压鼠模型中，敲低促进肥大的miR-23 a显示出减弱心脏肥大。然而，缺乏有效、安全、非免疫原性的递送miRNA模拟物或抑制剂的方法限制了临床转化。超声靶向微泡破坏（UTMD）代表了一种有吸引力的非免疫原性的治疗诊断递送策略，以局部调节心脏中的miRNA水平。已显示UTMD增强内吞作用，并且还可以诱导由于微泡振荡和塌陷而在细胞膜中形成瞬时孔，从而潜在地允许核苷酸直接进入细胞质。该提案的目的是开发一个利用超声和微泡来调节心脏中miRNA水平的平台。该平台可以潜在地用于递送任何感兴趣的miRNA模拟物或抑制剂。因此，我们假设UTMD介导的针对促肥大miR-23 a的Eschomir的递送将减弱苯肾上腺素诱导的心脏肥大。我们的3个具体目标是确定：（1）UTMD是否可以在体外将针对促肥大miRNA的阿司洛尔递送至心肌细胞;（2）UTMD是否可以将针对促肥大miRNA的阿司洛尔递送至跳动的高血压心脏;以及（3）UTMD介导的阿司洛尔从微泡中释放的作用机制。将针对miR-23 a及其下游靶标的表达水平、心肌细胞和心室肥大以及总体心脏功能来评价UTMD在不同声学条件下的功效。在超声影响下通过微泡释放的新的超高速成像将提供对有效UTMD机制的深入了解。最终，这项研究计划将为临床上可翻译的靶向递送平台提供基础，以治疗性地调节心脏中的miRNA水平。

DESCRIPTION (provided by applicant): Left ventricular hypertrophy (LVH), such as occurs in hypertension, carries an increased risk for cardiovascular events. Clinical evidence indicates that inhibition and regression of LVH is associated with improved cardiac function and a reduced risk of cardiovascular complications. MicroRNAs (miRNAs) are short endogenous RNAs that can regulate multiple genes. miRNA levels have been shown to significantly change in diseased human hearts. Modulation of miRNAs to treat cardiovascular disease is seen as a potentially powerful clinical tool; e.g. knockdown of miR-23a, which promotes hypertrophy, was shown to blunt cardiac hypertrophy in a hypertensive murine model. However, the lack of effective, safe, non-immunogenic methods for delivery of miRNA mimics or inhibitors limits clinical translation. Ultrasound targeted microbubble destruction (UTMD) represents an attractive non-immunogenic, theranostic delivery strategy to locally modulate miRNA levels in the heart. UTMD has been shown to enhance endocytosis and can also induce transient pores to form in cell membranes as a result of microbubble oscillation and collapse, potentially allowing nucleotides to enter the cytoplasm directly. The objective of this proposal is to develop a platform utilizing ultrasound and microbubbles to regulate miRNA levels in the heart. This platform can potentially be used to deliver any miRNA mimic or inhibitor of interest. Accordingly, we hypothesize that UTMD-mediated delivery of an antagomir directed against pro-hypertrophic miR-23a will attenuate phenylephrine-induced cardiac hypertrophy. Our 3 Specific Aims are to determine: (1) if UTMD can deliver an antagomir against a prohypertrophic miRNA to cardiomyocytes in vitro; (2) if UTMD can deliver an antagomir against a pro-hypertrophic miRNA to a beating, hypertensive heart; and (3) the mechanism of action involved in UTMD-mediated antagomir release from microbubbles. The efficacy of UTMD under varying acoustic conditions will be evaluated with respect to expression levels of miR-23a and its downstream targets, cardiomyocyte and ventricular hypertrophy, and overall cardiac function. Novel ultra high speed imaging of antagomir release by microbubbles under the influence of ultrasound will provide insights into mechanisms underlying effective UTMD regimes. Ultimately, this research program will provide a foundation for a clinically translatable targeted delivery platform to therapeuticaly regulate miRNA levels in the heart.