ROS signaling, intercellular communication and heart development and function

描述（由申请人提供）：摘要拟议研究的中心目的是定义一种新的活性氧（ROS）信号传导机制，以果蝇为模型系统，介导心肌细胞和非心肌细胞之间的相互作用，这对心脏的正常发育和功能至关重要。心肌细胞和非心肌细胞间通讯的紊乱是心律失常、心源性猝死和心力衰竭的主要原因。因此，更好地了解心肌细胞和非心肌细胞之间的功能相互作用是必要的，为人类心脏病的新的和改进的治疗方法的发展。果蝇心脏是阐明心肌细胞-非心肌细胞功能相互作用的精确分子基础的有效模型系统。果蝇心脏是一个由心肌细胞（CM）和非心肌细胞的心包细胞（PC）组成的线性管状结构。我们最近发表的研究表明，在正常的生理条件下，与CM相比，PC中的ROS水平升高。PC中的ROS激活下游D-p38 MAPK通路，该通路作用于CM以控制其发育和功能。这些发现为我们阐明ROS介导PC和CM功能相互作用的分子机制提供了新的机会，这将有助于实现我们的中心目标。基于我们已发表的和新的初步数据，我们将进一步描述果蝇PC中生理ROS-D-p38信号通路的组成和功能。我们的中心假设是，在果蝇心脏中，由ROS-D-p38（PC）→隔连接（SJ）蛋白（PC）→ TRPA通道（CM）→ Ca 2+内流/信号转导（CM）组成的信号通路介导了PC和CM之间基于ROS的旁分泌相互作用。该假设将通过三个具体目标进行检验：（1）确定心包细胞中ROS的细胞内来源，（2）定义SJ蛋白作为ROS-D-p38信号传导的心包细胞特异性靶标的作用，以及（3）定义TRPA离子通道蛋白作为ROS-D-p38信号传导的心肌细胞特异性靶标的作用。这些目标将通过遗传、生物成像和RNA测序实验的结合来实现。该项目有望揭示新的和重要的见解，了解基于ROS的旁分泌信号传导和心肌细胞和非肌细胞之间的功能相互作用的知之甚少的领域。这些知识可能有助于开发新的和改进的人类心脏病和衰竭疗法。

DESCRIPTION (provided by applicant): Abstract The central aim of the proposed research is to define a novel signaling mechanism of reactive oxygen species (ROS) in mediating the interaction between cardiac myocytes and nonmyocytes which is essential for proper heart development and function, using the fruit fly Drosophila as a model system. Perturbations of the intercellular communication between cardiac myocytes and nonmyocytes are a major source of cardiac arrhythmias, sudden cardiac death and heart failure. A better understanding of the functional interactions between cardiac myocytes and nonmyocytes is therefore necessary for the development of new and improved therapies for human heart diseases. The fruit fly heart serves as an efficient model system for elucidating the precise molecular basis of cardiac myocyte-nonmyocyte functional interactions. The fly heart is a linear tube comprising of cardiomyocytes (CMs) surrounded by nonmyocyte pericardial cells (PCs). Our recently published study showed that under normal, physiological conditions, levels of ROS are elevated in the PCs compared to the CMs. ROS in PCs activate a downstream D-p38 MAPK pathway that acts on the CMs to control their development and function. These findings provide new opportunities for us to elucidate the molecular mechanisms by which ROS could mediate the functional interaction between PC and CM, which will contribute to the achieving of our central aim. Building on our published and new preliminary data, we will further delineate the components and function of the physiological ROS-D-p38 signaling pathway in the Drosophila PCs. Our central hypothesis is that a signaling pathway comprised of ROS-D-p38 (PC) → Septate junction (SJ) proteins (PC) → TRPA channels (CM) → Ca2+ influx/signal transduction (CM) mediates the ROS-based paracrine interactions between PC and CM in the Drosophila heart. This hypothesis will be tested by three specific aims: (1) Determine the intracellular source(s) of ROS in pericardial cells, (2) Define the roles of SJ proteins as pericardial cell-specific targets of ROS-D-p38 signaling, and (3) Define the roles of TRPA ion channel proteins as cardiomyocyte-specific targets of ROS-D-p38 signaling. These aims will be addressed by a combination of genetic, bio-imaging and RNA-sequencing experiments. This project is expected to reveal novel and important insights into the poorly understood areas of ROS-based paracrine signaling and functional interactions between cardiac myocytes and nonmyocytes. This knowledge may facilitate the development of new and improved therapies for human heart disease and failure.