Micro-Sensors to Study Electrical and Mechanical Coupling of Injured Myocardium

摘要 心力衰竭仍然是美国发病率和死亡率的主要原因，困扰着近500万人。 最近，成年斑马鱼(Danio Rerio)已被用来模拟不同类型的心力衰竭，并用于研究 通过诱变筛选寻找遗传修饰物。然而，斑马鱼心脏的小尺寸阻碍了精确 基因改造后的电气和机械评估。在上一个资金周期中，我们 将柔性微电极阵列与高频超声换能器集成在一起，证明了早期 再生的心肌细胞缺乏整合到受损心脏所需的电学表型。我们进一步 显示房室瓣膜的压力梯度大于房室瓣膜的压力梯度。 脑室冷冻损伤后的脑室球瓣。然而，最初的上升和随后的正常化 心脏被动充盈波(E)和主动充盈波(A)充盈波(E/A比值)提示舒张期功能恢复。在下一个 在资金周期内，我们将把我们的微观传感能力与心肌病的新遗传模型相结合，以 化疗损伤后机电耦合及其遗传模型的研究进展 心肌病。我们的多学科团队建立了阿霉素(Dox)诱导的成年斑马鱼模型 心肌病(CM)作为一种保守的脊椎动物模型研究心肌损伤和再生 靶向ErbB2(HER2)/neu的乳腺癌化疗的反应。我们的团队进一步发展了 CM的三种小鼠遗传模型，即bag3基因敲除(KO)、mBAG3过表达(OE)和Imna KO。 我们进一步发展了一种正向遗传方法来识别Dox诱导的CM的遗传修饰物。飞行员 对&gt；500基因破碎型转座子(GBT)突变体的筛选已鉴定出4个GBT系，其中GBT419/rxraa (视黄醇X受体αa)类似于mTOR，可改善Dox诱导的CM后斑马鱼的存活。我们的目标 是将微型传感器与先进的成像技术相结合，以研究人体的导电和机械功能 损伤心肌对Dox诱导的反应和3种CM遗传模型。我们的假设是基因 GBT419/rxraa等修饰剂促进Dox诱导和遗传模型的机电耦合 Cm以恢复收缩功能。为了验证我们的假设，我们有三个目标：在目标1中，我们将确定 我们的Dox诱导和遗传模型中的电导。在目标2中，我们将演示机械 在我们的Dox诱导和遗传模型中发挥作用。在目标3中，我们将评估机电耦合 随后用CM修饰基因进行处理。总体而言，这些目标将为 利用正向遗传学发现治疗调节剂在心肌病中的机电耦合 恢复心脏功能。

ABSTRACT Heart failure remains the leading cause of morbidity and mortality in the US, afflicting nearly 5 million people. Recently, adult Zebrafish (Danio rerio) have been utilized to model different types of heart failure, and to search for genetic modifiers via mutagenesis screening. However, the small size of the zebrafish heart hinders precise electrical and mechanical assessments following genetic modifications. During the previous funding cycle, we integrated a flexible micro-electrode array with high-frequency ultrasonic transducers to demonstrate that early regenerating cardiomyocytes lack the electrical phenotypes needed to integrate into injured hearts. We further showed that the pressure gradient across the atrioventricular valve is greater than that across the ventriculobulbar valve following ventricular cryo-injury. However, the initial rise and subsequent normalization of ventricular passive (E) and active (A) filling waves (E/A ratios) indicate recovery of diastolic function. In the next funding cycle, we will combine our micro-sensing capacity with novel genetic models of cardiomyopathy to elucidate electromechanical coupling following chemotherapy-induced injury and genetic models of cardiomyopathy. Our multi-disciplinary team established an adult zebrafish model of doxorubicin (Dox)-induced cardiomyopathy (CM) as a conserved vertebrate model to investigate myocardial injury and regeneration in response to the breast cancer chemotherapy targeting ErbB2 (HER2)/NEU. Our team has further developed three murine genetic models of CM; namely, bag3 knockout (KO), mBAG3 overexpression (OE), and Imna KO. We have further developed a forward-genetic approach to identify genetic modifiers of Dox-induced CM. A pilot screen of >500 gene-breaking transposon (GBT) mutants has identified four GBT lines, of which GBT419/rxraa (retinoid X receptor alpha a) resembles mTOR to improve zebrafish survival following Dox-induced CM. Our goal is to integrate micro-sensors with advanced imaging to study electrical conduction and mechanical function of the injured myocardium in response to Dox-induced and 3 genetic models of CM. Our hypothesis is that genetic modifiers such as GBT419/rxraa promotes electromechanical coupling in Dox-induced and genetic models of CM to restore contractile function. To test our hypothesis, we have three aims: In Aim 1, we will determine electrical conduction in our Dox-induced and genetic models. In Aim 2, we will demonstrate mechanical function in our Dox-induced and genetic models. In Aim 3, we will assess electromechanical coupling following treatments with CM modifying genes. Overall, these aims will provide new insights into electromechanical coupling in cardiomyopathy using forward-genetics to discover therapeutic modifiers capable of restoring heart function.