Ultrasound-mediated modulation of microRNAs for treatment of cardiac hypertrophy

描述(由申请人提供)：左心室肥厚(LVH)，如高血压，会增加心血管事件的风险。临床证据表明，抑制和消退左心室肥厚与改善心功能和降低心血管并发症的风险有关。MicroRNAs(MiRNAs)是一种短小的内源RNA，可以调节多个基因。MiRNA水平已被证明在患病的人类心脏中发生了显着变化。调控miRNAs治疗心血管疾病被认为是一种潜在的强大临床工具；例如，抑制miR-23a，促进肥厚，被证明在高血压小鼠模型中可以钝化心肌肥厚。然而，缺乏有效的、安全的、非免疫原性的传递miRNA模拟物或抑制剂的方法限制了临床翻译。超声靶向微泡破坏(UTMD)代表了一种有吸引力的非免疫原性、治疗给药策略，可以局部调节心脏中miRNA的水平。UTMD已被证明可以增强内吞作用，也可以由于微泡的振荡和坍塌而诱导细胞膜上形成瞬时毛孔，从而潜在地允许核苷酸直接进入细胞质。这项提议的目标是开发一个利用超声波和微泡来调节心脏中miRNA水平的平台。该平台可能被用来提供任何感兴趣的miRNA模拟物或抑制剂。因此，我们假设UTMD介导的针对促肥厚miR-23a的安非他明的递送将减轻苯肾上腺素诱导的心肌肥厚。我们的三个具体目标是确定：(1)UTMD是否能在体外向心肌细胞递送抗肥大miRNA的抗药；(2)UTMD是否能将抗肥大miRNA的抗药递送到跳动的高血压心脏；以及(3)UTMD介导的Anagomir从微泡中释放的作用机制。UTMD在不同声学条件下的疗效将根据miR-23a及其下游靶点的表达水平、心肌细胞和心室肥厚以及整体心功能进行评估。超声作用下微泡释放安托格玛的新型超高速成像将为有效的UTMD机制提供深入的了解。最终，这项研究计划将为临床可翻译的靶向传递平台提供基础，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.