Teledyne Scientific & Imaging Co. LLC, Thousand Oaks, CA 91360, USA.
J R Soc Interface. 2013 Apr 24;10(84):20130266. doi: 10.1098/rsif.2013.0266. Print 2013 Jul 6.
We hypothesize that a population of migrating cells can form patterns when changes in local strains owing to relative cell motions induce changes in cell motility. That the mechanism originates in competing rates of motion distinguishes it from mechanisms involving strain energy gradients, e.g. those generated by surface energy effects or eigenstrains among cells, and diffusion-reaction mechanisms involving chemical signalling factors. The theory is tested by its ability to reproduce the morphological characteristics of enamel in the mouse incisor. Dental enamel is formed during amelogenesis by a population of ameloblasts that move about laterally within an expanding curved sheet, subject to continuously evolving spatial and temporal gradients in strain. Discrete-cell simulations of this process compute the changing strain environment of all cells and predict cell trajectories by invoking simple rules for the motion of an individual cell in response to its strain environment. The rules balance a tendency for cells to enhance relative sliding motion against a tendency to maintain uniform cell-cell separation. The simulations account for observed waviness in the enamel microstructure, the speed and shape of the 'commencement front' that separates domains of migrating secretory-stage ameloblasts from those that are not yet migrating, the initiation and sustainment of layered, fracture-resistant decussation patterns (cross-plied microstructure) and the transition from decussating inner enamel to non-decussating outer enamel. All these characteristics can be correctly predicted with the use of a single scalar adjustable parameter.
我们假设，当相对细胞运动引起的局部应变变化诱导细胞运动性变化时，迁移细胞群可以形成模式。该机制源于运动速率的竞争，这使其有别于涉及应变能梯度的机制，例如由表面能效应或细胞内本征应变引起的机制，以及涉及化学信号因子的扩散-反应机制。该理论通过其在重现小鼠切牙釉质形态特征方面的能力得到检验。在釉质发生期间，釉质由一群釉原细胞形成，这些细胞在不断演变的空间和时间应变梯度下在扩张的曲面上侧向移动。对该过程的离散细胞模拟计算了所有细胞的不断变化的应变环境，并通过调用单个细胞在其应变环境下运动的简单规则来预测细胞轨迹。这些规则平衡了细胞增强相对滑动运动的趋势与保持均匀细胞间分离的趋势。这些模拟解释了釉质微观结构中的波纹、将正在迁移的分泌期釉原细胞与尚未迁移的细胞分隔开来的“起始前沿”的速度和形状、分层的、抗断裂的交错模式（交叉层微观结构）的开始和维持以及从交错的内釉质到非交错的外釉质的转变。所有这些特征都可以通过使用单个标量可调参数正确预测。
