COMPUTATIONAL IMAGING OF AVIAN HEART MORPHOGENESIS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 在禽类胚胎中，两侧心脏原基在中线融合形成一条管状结构。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，以防止心脏融合-导致贲门裂。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，这是正确的心管融合所必需的。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，这些“原料”被不依赖于细胞自主运动的物理组织层面的事件所取代；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)确定正常和实验扰动的胚胎在禽类双侧心管融合过程中中胚层细胞和细胞外基质原纤维的位置-命运图；2)计算由于自主运动和组织对流导致的细胞总位移的分量；3)计算正常和实验扰动的胚胎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。相关性：计算机成像数据将表明机械模式在心脏形态发生过程中的重要性。预测性计算机模型将描述心脏畸形的生物力学特征，并可能提供有助于预防相关心脏缺陷的信息。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In the avian embryo, bilateral heart primordia fuse to form a tube 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 heart fusion - resulting in cardia bifida. 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 fusion. Accordingly, the following hypotheses will be tested: First, that cells and ECM components required for heart morphogenesis are recruited from distant sites; Second, that these "raw materials" are displaced by physical tissue-level events that are not dependent on autonomous cell motion; 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 bilateral heart tube fusion in normal and experimentally perturbed embryos; 2) Compute the component of total cell displacements attributable to autonomous motion 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. RELEVANCE: Computational imaging data will indicate the importance of mechanical patterning during heart morphogenesis. Predictive computer models will characterize the bio-mechanics of heart malformations and may provide information to help prevent related heart defects.