Computational Imaging of ECM During Avian Heart Morphogenesis

描述（由申请人提供）：在禽类胚胎中，心脏祖细胞区域在中线融合形成管状心脏。随后，该管经历屈曲和旋转的过程;导致环状心脏。我们的长期目标是确定多个遗传和信号缺陷是否汇聚在一个共同的机械关系中，以防止正确的心脏形态发生。已知局部细胞-细胞外基质（ECM）相互作用对于早期心脏发育至关重要。此外，我们提出，全球组织变形直接影响细胞运动和正在进行的重组的ECM必要的适当的心管形成和循环。因此，将测试以下假设：首先，心脏形态发生所需的细胞和ECM组分是从远处募集的;其次，组织水平的细胞和ECM组分是从远处募集的。第三，适当的心脏形态发生需要细胞集合体和募集的ECM原纤维的持续组织水平重组;第四，对机械微环境的扰动，如局部张力场或细胞-ECM相互作用的破坏，将导致可再现的心脏畸形。因此，我们将：1）在正常和实验扰动胚胎中的禽类管状心脏形成期间确定中胚层细胞和ECM原纤维位置-命运图; 2）计算归因于局部自主细胞位移与组织对流的总细胞位移的分量; 3）计算正常和实验扰动胚胎的心脏形成区域中的应变;（4）构建包含管状心脏形态发生的预测性有限元模型。这些目标将使用DIC和落射荧光时间推移显微镜和随后的计算分析所产生的图像帧来实现。 公共卫生相关性体内延时成像和计算分析将确定早期心脏形成期间细胞和ECM纤维的运动模式。将运动数据与变形数据联系起来，将有助于深入了解心脏形态发生过程中机械模式的重要性，这是多个遗传信号事件的结果。预测计算机模型将描述心脏畸形的生物力学特征，并提供有用的信息来帮助预防相关的心脏缺陷。

DESCRIPTION (provided by applicant): In the avian embryo, cardiac progenitor fields fuse to form a tubular heart at the midline. Subsequently, this tube undergoes a process of flexion and rotation; resulting in a looped heart. Our long-term goal is to determine if multiple genetic and signaling defects converge at a common mechanical nexus to prevent proper heart morphogenesis. It is known that local cell- extracellular matrix (ECM) interactions are critical for early heart development. In addition, we propose that global tissue deformations directly influence cell motion and the ongoing reorganization of the ECM necessary for proper heart tube formation and looping. Accordingly, the following hypotheses will be tested: First, that cells and ECM components required for heart morphogenesis are recruited from distant sites; Second, that tissue-level (convective) events are involved in the displacement of these raw materials ; Third, that proper heart morphogenesis requires ongoing tissue-level reorganization of cell collectives and the recruited ECM fibrils; and Fourth, that perturbations to the mechanical micro-environment, such as disruption of local tension fields or cell-ECM interactions, will cause reproducible heart malformations. Accordingly, we will: 1) Determine mesodermal cell and ECM fibril position-fate maps during avian tubular heart formation in normal and experimentally perturbed embryos; 2) Compute the component of total cell displacements attributable to local autonomous cell displacements versus tissue convection; 3) Compute strain in the heart-forming regions of normal and experimentally perturbed embryos; and 4) Construct a predictive finite element model encompassing tubular heart morphogenesis. These aims will be accomplished using DIC and epifluorescence time lapse microscopy and subsequent computational analyses of the resulting image frames. PUBLIC HEALTH RELEVANCE In vivo time-lapse imaging and computational analyses will define the motion patterns of cells and ECM fibrils during early heart formation. Relating motion data to deformation data will provide insights into the importance of mechanical patterning during heart morphogenesis, which is the result of multiple genetic signaling events. Predictive computer models will characterize the bio-mechanics of heart malformations and provide useful information to help prevent related heart defects.