CAREER: Mechano-Metabolic Control of Electrical Remodeling of Human Induced Pluripotent Stem Cell Derived Engineered Heart Muscle

这个教师早期职业发展（CAREER）奖支持研究，以了解如何在实验室中从干细胞生长心肌，并使用该肌肉来预测药物将如何影响患者的心脏。诱导多能干细胞（iPSC）是来自健康成年患者的细胞，它们被“重新连接”，以便它们可以形成体内发现的任何类型的细胞。目前，在实验室中从iPSC生长的心肌更类似于胎儿的心肌，而不是成人的心肌。这意味着实验室生长的肌肉不能准确预测药物对患者的影响。这是开发治疗心脏病药物的主要障碍，心脏病是美国的主要死因。出生后不久，婴儿的心脏必须以更强的力量泵，因为他们的血压增加。与此同时，他们心脏的能量来源从糖转移到脂肪。先前的研究表明，单独模仿这些机械阻力的变化，或者将能量来源从糖改变为脂肪，可以增强实验室培养的心肌。该研究项目将支持将这些变化结合起来，目标是生产更准确预测药物影响患者方式的肌肉。此外，执行这项工作的科学家和当地高中教师之间的计划合作将使那些在STEM管道中代表性不足的学生接触科学和工程。在心脏发育的围产期和出生后阶段，心脏上的机械力（前负荷和后负荷）增加。同时，ATP来源从葡萄糖转换为脂肪酸。本研究假设机械负荷和ATP来源以协同的方式通过调节过氧化物酶体激活受体（PPAR）信号传导来引起来自iPSC的心肌细胞的电成熟。为了解决这一假设，PI将利用高通量、iPSC衍生的微型心肌阵列技术。应用于微组织的生物物理线索将使用线性致动器来控制，以拉伸组织（预加载）和磁流变弹性体基底，以控制基底组织的刚度（后加载）。将使用电压敏感染料、遗传钙指示剂（GCaMP 6 f）、高速显微镜和自动视频分析确定微组织电生理学的总体变化。使用离子通道特异性阻断药物、免疫染色和RNAseq的组合，电生理学的这些总体变化将与特定离子通道表达的变化相关联。最后，将进行一系列PPAR通路修饰药物的研究，以特异性地探测PPAR通路在iPSC-心肌细胞电成熟中的作用。该研究的首要重点是深入了解机械线索如何与代谢底物等可溶性化学线索协同作用，以影响细胞命运和功能。该项目将使PI能够推进机械生物学的知识基础，并建立他的长期生物工程职业生涯。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Faculty Early Career Development (CAREER) award supports research to understand how to grow heart muscle from stem cells in the laboratory and use that muscle to predict how drugs will affect patients’ hearts. Induced pluripotent stem cells (iPSC) are cells from healthy adult patients that are “rewired” so that they can form any type of cell found in the body. Currently, heart muscle grown from iPSC in the laboratory is more similar to heart muscle in a fetus than an adult. This means that lab grown muscle does not accurately predict the way drugs will affect patients. This is a major obstacle to developing drugs to treat heart disease, the leading cause of death in the United States. Shortly after birth, babies’ hearts must pump with stronger force because their blood pressure increases. At the same time, their hearts’ energy source shifts from sugar to fat. Previous research suggests that individually mimicking these changes in mechanical resistance to pumping, or changing the energy source from sugar to fat, can enhance lab-grown heart muscle. This research project will support combining those changes, with the goal of producing muscle that more accurately predicts the way drugs will affect patients. In addition, planned collaborations between the scientists performing this work and local high school teachers will expose students who are underrepresented in the STEM pipeline to science and engineering. In the perinatal and postnatal stages of heart development, mechanical forces on the heart (preload and afterload) increase. Concurrently, ATP-sourcing switches from glucose to fatty acids. This research hypothesizes that mechanical loading and ATP-sourcing act in a synergistic manner to elicit electrical maturation of cardiomyocytes derived from iPSC by regulating Peroxisome Proliferator Activated Receptor (PPAR) signaling. To address this hypothesis, the PI will leverage a high-throughput, iPSC-derived micro-heart muscle array technology. Biophysical cues applied to the micro-tissues will be controlled using linear actuators to stretch tissue (preload) and magneto-rheoelastomeric substrates to control the rigidity of the substrate tissues work against (afterload). Overall changes in micro-tissue electrophysiology will be determined using voltage sensitive dye, genetic calcium indicator (GCaMP6f), high-speed microscopy and automated video analyses. Using a combination of ion channel specific blocking drugs, immunostaining and RNAseq, these overall changes in electrophysiology will be linked to changes in expression of specific ion channels. Finally, a series of studies with PPAR-pathway modifying drugs will be performed to specifically probe the role for the PPAR-pathway in electrical maturation of iPSC-cardiomyocytes. The overarching focus of the research is to obtain deep understanding of how mechanical cues synergize with soluble, chemical cues like the metabolic substrate, to affect cellular fate and function. This project will allow the PI to advance the knowledge base in mechanobiology and establish his long-term bioengineering career.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.