Shaping of simple organ by anisotropic biomechanical forces

描述(申请人提供)：通过各向异性生物力学力量塑造一个简单的器官动物器官的形式多样，精致，但高度可复制，对其功能至关重要。器官的形态是由一组有限的形态发生运动产生的，这些运动最终涉及机械力，由细胞-细胞和细胞-细胞外基质(ECM)相互作用等主要影响驱动和响应。我们对这些如何协调转化为在体内形成组织的力平衡的理解目前还很原始。特别是，尽管最近的工作揭示了钙粘附素介导的皮质张力如何调节极化细胞的行为，但在活体动物中有组织的ECM如何产生的力如何驱动器官形态发生仍然知之甚少。这项工作的长期目标是了解基因组如何协调整合在组织中的机械力，以驱动特定的三维形状。我们将对这个问题进行简单的调查。 果蝇的卵室，它经历了一个基本的发育转变，从各向同性的形状，沿着一个单一的轴拉长2.5倍。组织伸长在许多发育中的动物器官中是一个广泛保守和关键的事件，重要的是，果蝇卵的伸长涉及细胞-细胞和细胞-基质的相互作用。它还涉及到细胞的集体迁移，建立了一种独特的极化ECM。因此，果蝇卵室位于一个“甜蜜点”，具有足够的复杂性来捕捉主要的脊椎动物器官的形态发生过程，但也有足够的简单性和可操作性来阐明一般的范例。这项提议的具体目标是确定ECM产生的各向异性力是如何塑造正在生长的卵室的。我们假设，组织旋转建立了一个具有不同机械性质的平面极化的ECM，并通过各向异性地改变细胞与细胞的相互作用来指导极化的细胞重排。我们将通过将果蝇的遗传可操纵性与先进的成像技术以及最近建立的生物力学分析相结合来测试这一假设，以测量和操纵所涉及的力。4D成像结合定量计算分析、激光切割和力敏生物力学探头可测量组织张力和ECM硬度。对不能伸长的突变和操控组织的分析将揭示产生蛋白质和机械各向异性的原因机制，包括细胞迁移的作用。已发现的机制将使我们了解人类发育缺陷和其他疾病，这些疾病是由形态发生机制改变引起的。

DESCRIPTION (provided by applicant): Shaping of a simple organ by anisotropic biomechanical forces the diverse, elaborate but highly replicable forms of animal organs are critical for their functions. Organ forms are generated by a limited set of morphogenetic movements that ultimately involve mechanical forces, driven by and responsive to major influences such as cell-cell and cell-extracellular matrix (ECM) interactions. Our understanding of how these coordinately translate into a force balance that shapes a tissue in vivo is currently primitive. In particular, while recent work has revealed much about how cadherin-mediated cortical tension can regulate polarized cell behaviors, how forces created by organized ECMs in living animals drive organ morphogenesis remains poorly understood. The long-term goal of this work is to understand how the genome orchestrates mechanical forces that are integrated within a tissue to drive a specific three-dimensional shape. We will investigate this question in a simple organ, the Drosophila egg chamber, which undergoes an elemental developmental transition from an isotropic shape to elongate 2.5-fold along a single axis. Tissue elongation is a broadly conserved and critical event in many developing animal organs, and importantly, Drosophila egg elongation involves cell-cell and cell- matrix interactions. It also involves a collective cell migration that builds a distinctive polarized ECM. The Drosophila egg chamber thus lies at a 'sweet spot' with sufficient complexity to capture major vertebrate organ morphogenetic processes but sufficient simplicity and manipulability to elucidate general paradigms. The specific objective of this proposal is to determine how anisotropic forces generated by the ECM sculpt the growing egg chamber. We hypothesize that tissue rotation builds a planar-polarized ECM with distinct mechanical properties, and directs polarized cell rearrangements by anisotropically altering cell-cell interactions. We will test this hypothesis by combining the genetic manipulability of Drosophila with advanced imaging techniques and recently established biomechanical assays to measure and manipulate the forces involved. 4D imaging accompanied by quantitative computational analysis, laser severing and force-sensing biomechanical probes will measure tissue tension and ECM rigidity. Analysis of mutant and manipulated tissues that fail to elongate will reveal causal mechanisms generating protein and mechanical anisotropy, including the role of cell migration. The mechanisms uncovered will inform our understanding of human developmental defects and other diseases arising from altered mechanics of morphogenesis.