Oliveri Hadrien, Traas Jan, Godin Christophe, Ali Olivier
Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Inria, 69342, Lyon, France.
J Math Biol. 2019 Feb;78(3):625-653. doi: 10.1007/s00285-018-1286-y. Epub 2018 Sep 12.
A crucial question in developmental biology is how cell growth is coordinated in living tissue to generate complex and reproducible shapes. We address this issue here in plants, where stiff extracellular walls prevent cell migration and morphogenesis mostly results from growth driven by turgor pressure. How cells grow in response to pressure partly depends on the mechanical properties of their walls, which are generally heterogeneous, anisotropic and dynamic. The active control of these properties is therefore a cornerstone of plant morphogenesis. Here, we focus on wall stiffness, which is under the control of both molecular and mechanical signaling. Indeed, in plant tissues, the balance between turgor and cell wall elasticity generates a tissue-wide stress field. Within cells, mechano-sensitive structures, such as cortical microtubules, adapt their behavior accordingly and locally influence cell wall remodeling dynamics. To fully apprehend the properties of this feedback loop, modeling approaches are indispensable. To that end, several modeling tools in the form of virtual tissues have been developed. However, these models often relate mechanical stress and cell wall stiffness in relatively abstract manners, where the molecular specificities of the various actors are not fully captured. In this paper, we propose to refine this approach by including parsimonious biochemical and biomechanical properties of the main molecular actors involved. Through a coarse-grained approach and through finite element simulations, we study the role of stress-sensing microtubules on organ-scale mechanics.
发育生物学中的一个关键问题是，在活组织中细胞生长是如何协调的，从而产生复杂且可重复的形状。我们在此研究植物中的这个问题，在植物中坚硬的细胞外壁阻止细胞迁移，形态发生主要源于膨压驱动的生长。细胞如何响应压力而生长，部分取决于其细胞壁的力学特性，而细胞壁通常是异质性、各向异性且动态变化的。因此，对这些特性的主动控制是植物形态发生的基石。在这里，我们聚焦于细胞壁刚度，它受分子信号和力学信号的共同控制。实际上，在植物组织中，膨压与细胞壁弹性之间的平衡产生了一个全组织范围的应力场。在细胞内部，诸如皮层微管等机械敏感结构会相应地调整其行为，并局部影响细胞壁重塑动力学。为了全面理解这个反馈回路的特性，建模方法必不可少。为此，已经开发了几种以虚拟组织形式存在的建模工具。然而，这些模型通常以相对抽象的方式关联机械应力和细胞壁刚度，其中并未充分体现各种作用因子的分子特异性。在本文中，我们提议通过纳入所涉及的主要分子作用因子的简约生化和生物力学特性来完善这种方法。通过粗粒度方法和有限元模拟，我们研究了应力感知微管在器官尺度力学中的作用。
