Shear stress and light-field to elucidate the initiation of cardiac outflow tract

切应力和光场对心脏流出道起始的研究 生物力学力调节心脏形态发生和机械敏感信号的突变 导致先天性心脏缺陷。在上一个融资周期中，我们的团队定制了一个Light- 具有亚体素分辨率的薄片荧光显微镜（LSFM），可增强所需的轴向分辨率， 提供大视野。该激光光学系统允许对脉动剪切应力与振荡剪切应力进行成像- 介导的Notch信号传导以启动内皮细胞小梁形成。我们证明了空间（λ/λ x）和 剪切应力的时间（Δ T/Δ T）变化调节Notch-EphrinB 2-Neureguilin-1信号传导， 内皮素激活促进小梁形成增殖的erb-B2受体酪氨酸激酶（ErbB 2）。 通过整合LSFM、计算和转基因模型，我们进一步建立了小梁形成消散 心内剪切应力产生的动能;因此，减轻心室重塑。但委员会仍 尚不清楚心肌收缩力降低或心内血流改变的后果 瓣膜形态发生的动力学。因此，我们寻求将光片（贝塞尔-高斯光束阵列）与 新的2）光场（微透镜阵列）。前者提供无衍射照明，后者提供 容积检测作为心肌收缩性和心内血流动力学成像的范式转变 流出道（OFT）。我们的初步研究表明，剪切介导的Notch 1b表达， OFT的内皮细胞调节内皮-间质转化（EndoMT）;然而， 心肌收缩力和心内切应力的机械传导 相互作用以形成二尖瓣和随后重塑为多尖瓣的瓣膜仍然是难以捉摸的。所以我们 假设是新的光场系统与成像计算的集成增强了时空 将心肌收缩与心内血流动力学分离所需的分辨率， Notch 1b-EndoMT介导OFT中的瓣膜形态发生。在目标1中，我们计划将光片与 用于OFT中瓣膜形成的4-D体积成像的新光场系统。我们的目标是 心肌收缩力和心内剪切应力。在目标2中，我们将演示 心内剪应力和心肌收缩力之间相互作用是瓣膜形态发生的基础。我们 目的是将血流动力学剪切与介导Notch 1b介导的EndoMT的收缩力分离。在 目的3，我们将确定剪切应力和收缩性的相对作用，Notch 1b介导的 EndoMT。我们的目标是阐明收缩力和心内应激在Notch 1b-1信号传导中的相对作用。 二尖瓣形成的EndoMT信号转导。总的来说，我们的团队旨在建立一个微观的， 心内血流动力学和心肌收缩力相互作用以调节OFT瓣膜的环境 对主动脉瓣疾病有临床意义。

Shear Stress and Light-Field to Elucidate the Initiation of Cardiac Outflow Tract Biomechanical forces modulate cardiac morphogenesis, and mutations in mechano-sensitive signaling pathways result in congenital heart defects. During the previous funding cycle, our team custom-built a Light- Sheet Fluorescence Microscopy (LSFM) with sub-voxel resolution to enhance axial resolution needed to provide a large field-of-view. This laser optical system allowed for imaging pulsatile vs. oscillatory shear stress- mediated Notch signaling to initiate endocardial trabeculation. We demonstrated that spatial (/x) and temporal (/t) variations in shear stress modulates Notch-EphrinB2-Neureguilin-1 signaling in the endocardium to activate erb-B2 receptor tyrosine kinase (ErbB2) that promotes proliferation of trabeculation. By integrating LSFM, computation, and transgenic models, we further established that trabeculation dissipates intracardiac shear stress-generated kinetic energy; thus, mitigating ventricular remodeling. However, it remains unclear what would be the consequences of reduced myocardial contractility or altered intracardiac flow dynamics on valve morphogenesis. Thus, we seek to integrate light-sheet (Bessel-Gaussian beam arrays) with a new 2) light-field (microlens array). The former provides non-diffracting illumination, and the latter provides volumetric detection as a paradigm shift to image both myocardial contractility and intracardiac flow dynamics in the outflow tract (OFT). Our preliminary study reveals that shear-mediated Notch1b expression in the endocardium of OFT regulates endothelial-to-mesenchymal transition (EndoMT); however, the mechanotransduction causation whereby myocardial contractility and intracardiac shear stress reciprocally interact to form bicuspid valves and subsequent remodeling to multi-cuspid valves remains elusive. Thus, our hypothesis is that integration of the new light-field system with imaging computation enhances spatiotemporal resolution needed to decouple myocardial contraction from intracardiac flow dynamics that modulates Notch1b-EndoMT to mediate valve morphogenesis in the OFT. In Aim 1, we plan to integrate light-sheet with the new light-field system for 4-D volumetric imaging of valve formation in the OFT. Our goal is to capture myocardial contractility and intracardiac shear stress at one snapshot. In Aim 2, we will demonstrate the interaction between intracardiac shear stress and myocardial contractility underlying valve morphogenesis. Our goal is to decouple hemodynamic shear from contractile forces that mediate Notch1b-mediated EndoMT. In Aim 3, we will determine the relative role of shear stress and contractility underlying Notch1b-mediated EndoMT. Our goal is to elucidate the relative role of contractility and intracardiac stress to transmit Notch1b- EndoMT signaling underlying bicuspid-valve formation. Overall, our team aims to establish the micro- environment in which intracardiac flow dynamics and myocardial contractility interact to modulate OFT valve formation, with clinical significance to aortic valvular disease.