Computational Imaging of ECM During Avian Heart Morphogenesis

描述(申请人提供)：在禽类胚胎中，心脏祖细胞区域融合，在中线形成管状心脏。随后，这个管子经历一个弯曲和旋转的过程，导致心脏环状。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连接处，以阻止正确的心脏形态发生。已知局部细胞-细胞外基质(ECM)相互作用对心脏早期发育至关重要。此外，我们认为，整体组织变形直接影响细胞运动和正在进行的ECM重组，这是正确的心管形成和循环所必需的。因此，将检验以下假设：首先，心脏形态发生所需的细胞和细胞外基质成分是从遥远的地点招募来的；其次，组织层面的(对流)事件参与了这些原材料的置换；第三，心脏形态发生需要持续的组织层面的细胞集体重组和招募的细胞外基质纤维；第四，对机械微环境的扰动，例如破坏局部应力场或细胞与细胞外基质的相互作用，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中胚层细胞和细胞外基质原纤维的位置-命运图；2)计算局部自主细胞位移与组织对流引起的细胞总位移的分量；3)计算正常和实验扰动胚胎的心脏形成区域的应变；以及4)构建包含管状心脏形态发生的预测有限元模型。这些目标将使用DIC和荧光延时显微镜以及随后对产生的图像帧进行计算分析来实现。 与公众健康相关的活体时间推移成像和计算分析将定义心脏形成早期细胞和细胞外基质原纤维的运动模式。将运动数据与变形数据相关联将有助于深入了解机械模式在心脏形态发生过程中的重要性，心脏形态发生是多个遗传信号事件的结果。预测性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.