Computational Imaging of ECM During Avian Heart Morphogenesis

描述（由申请人提供）：在禽类胚胎中，心脏祖区在中线融合形成管状心脏。随后，这个管子经历了一个弯曲和旋转的过程；导致心脏循环。我们的长期目标是确定多种遗传和信号缺陷是否会聚在一个共同的机械联系上，以阻止正常的心脏形态发生。众所周知，局部细胞-细胞外基质（ECM）相互作用对早期心脏发育至关重要。此外，我们提出整体组织变形直接影响细胞运动和正常心脏管形成和环所必需的ECM的持续重组。因此，以下假设将得到验证：首先，心脏形态发生所需的细胞和ECM成分是从远处招募的；第二，组织层面的（对流）事件参与了这些原材料的置换；第三，正常的心脏形态发生需要持续的组织水平的细胞集体重组和募集的ECM原纤维；第四，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，将导致可复制的心脏畸形。因此，我们将：1)在正常和实验扰动的胚胎中确定鸟类管状心脏形成过程中中胚层细胞和ECM原纤维的位置-命运图；2)计算可归因于局部自主细胞位移与组织对流的总细胞位移分量；3)计算正常胚胎和实验扰动胚胎心脏形成区的应变；4)构建包含管状心脏形态发生的预测有限元模型。这些目标将完成使用DIC和荧光时移显微镜和随后的计算分析所得的图像帧。

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.