Microphysiological Systems to Study Hypoxic Cardiac Injury

项目总结/摘要 急性心肌梗死（MI）伴冠状动脉闭塞后， 血液供应限制心肌的氧合，导致形成陡峭的氧（O2）梯度 从含氧量正常的活组织到缺氧的受损组织界面处存在局部功能障碍 在常氧组织和缺氧组织之间，称为边界区。再灌注恢复血液流动， O2的组织，而且还诱导缺血再灌注损伤（IRI），病理生理学导致进一步的组织 损害这些缺氧性心脏损伤的病理过程尚未明确确定， 部分原因是缺乏实验工具来概括不同的时空O2梯度特征， 我和IRI该提案的目标是设计具有严格O2控制的微生理系统， 研究在O2梯度中激活的分子途径，以及对心肌细胞（CM）的影响 功能，以获得对缺氧损伤的心脏反应的全面看法。本报告概述的目标 该提案将建立在Rexius博士使用微流体控制O2水平的专业知识基础上， 芯片技术，以促进缺氧心脏损伤的功能和机制的理解。在 在指导阶段，Rexius博士将使用工程和药理学方法来控制旁分泌 在MI边界区微装置模型中的相互作用，并确定旁分泌介导的缺氧- 含氧量正常的细胞间通讯在定义跨O2梯度的空间代谢异质性（目的 1）。蛋白质组学和miRNA分析将用于鉴定和验证外泌体货物作为旁分泌的转移。 改变CM代谢的机制。现有的O2控制框架将用于设计一个 微生理系统来模拟IRI和牵引力，肌节缩短， 和钙瞬变，以及它们对O2张力的依赖性，以通过实时成像监测功能障碍（目的2）。在 独立阶段，这些系统的修改版本将检查O2再灌注率对CM的影响 自噬是细胞物质降解和再循环的过程（Aim 3）。 该项目和指导计划将使Rexius博士能够发展以下方面的技能：（1）非侵入性光学 代谢参数的测量，（2）外泌体蛋白质组学和miRNA数据集的生物信息学分析， (3)牵引力显微镜，（4）沟通，指导和实验室管理，以准备领导 学术界的独立研究项目。Rexius博士将由Megan McCain博士在 南加州大学（USC）和南加州大学凯克医学院的Ching-Ling（Ellen）Lien博士 还有洛杉矶儿童医院Rexius博士还招募了Keyue Shen博士（南加州大学）和Jennifer货车博士 Eyk（Cedars-Sinai）担任顾问，以支持她的科学和专业发展。完成目标 将揭示新的见解CM响应异质O2景观。

Project Summary/Abstract Following the onset of an acute myocardial infarction (MI) with coronary artery occlusion, the restricted blood supply limits oxygenation of the myocardium, resulting in the formation of a steep oxygen (O2) gradient from normoxic, viable tissue to hypoxic, damaged tissue. A site of regional dysfunction exists at the interface between the normoxic and hypoxic tissue, known as the border zone. Reperfusion restores the flow of blood and O2 to the tissue, but also induces ischemia reperfusion injury (IRI), a pathophysiology resulting in further tissue damage. The pathological processes underlying these hypoxic cardiac injuries are not definitively established, in part due to a lack of experimental tools to recapitulate the diverse spatiotemporal O2 gradients characteristic of MI and IRI. The goal of this proposal is to engineer microphysiological systems with tight O2 control to investigate the molecular pathways activated in O2 gradients, and the resulting effects on cardiomyocyte (CM) function, to obtain a comprehensive view of the cardiac response to hypoxic injury. The aims outlined in this proposal will build on the expertise of Dr. Rexius in controlling O2 levels using microfluidics and integrate Heart- on-a-Chip technologies to advance the functional and mechanistic understanding of hypoxic cardiac injury. In the mentored phase, Dr. Rexius will use engineering and pharmacological approaches to control paracrine interactions in an MI border zone microdevice model and determine the role of paracrine-mediated hypoxic- normoxic intercellular communication in defining the spatial metabolic heterogeneity across an O2 gradient (Aim 1). Proteomic and miRNA analysis will be used to identify and validate transfer of exosome cargo as a paracrine mechanism altering CM metabolism. The existing O2 control framework will be utilized to engineer a microphysiological system to model IRI and multiplex measurements of traction force, sarcomere shortening, and calcium transients, and their dependence on O2 tension, to monitor dysfunction with live imaging (Aim 2). In the independent phase, modified versions of these systems will examine the effect of O2 reperfusion rate on CM function and the regulation of autophagy, a process by which cellular material is degraded and recycled (Aim 3). The project and mentorship plan will allow Dr. Rexius to develop skills in (1) non-invasive optical measurements of metabolic parameters, (2) bioinformatics analysis of exosome proteomic and miRNA datasets, (3) traction force microscopy, and (4) communication, mentoring, and laboratory management to prepare to lead an independent research program in academia. Dr. Rexius will be co-mentored by Dr. Megan McCain at the University of Southern California (USC) and Dr. Ching-Ling (Ellen) Lien at the Keck School of Medicine of USC and Children’s Hospital Los Angeles. Dr. Rexius has also enlisted Dr. Keyue Shen (USC) and Dr. Jennifer Van Eyk (Cedars-Sinai) as advisors to support her scientific and professional development. Completion of the aims will reveal novel insights into CM responses in heterogeneous O2 landscapes.