Data from: Cell-size distribution in epithelial tissue formation and homeostasis

How cell growth and proliferation are orchestrated in living tissues to achieve a given biological function is a central problem in biology. During development, tissue regeneration and homeostasis, cell proliferation must be coordinated by spatial cues in order for cells to attain the correct size and shape. Biological tissues also feature a notable homogeneity of cell size, which, in specific cases, represents a physiological need. Here, we study the temporal evolution of the cell-size distribution by applying the theory of kinetic fragmentation to tissue development and homeostasis. Our theory predicts self-similar probability density function (PDF) of cell size and explains how division times and redistribution ensure cell size homogeneity across the tissue. Theoretical predictions and numerical simulations of confluent non-homeostatic tissue cultures show that cell size distribution is self-similar. Our experimental data confirm predictions and reveal that, as assumed in the theory, cell division times scale like a power-law of the cell size. We find that in homeostatic conditions there is a stationary distribution with lognormal tails, consistently with our experimental data. Our theoretical predictions and numerical simulations show that the shape of the PDF depends on how the space inherited by apoptotic cells is redistributed and that apoptotic cell rates might also depend on size.活体组织中细胞生长与增殖如何被协同调控以实现特定生物学功能，是生物学领域的核心研究问题。在发育、组织再生及稳态维持过程中，细胞增殖必须受到空间信号的协调调控，才能使细胞获得正确的尺寸与形态。生物组织还普遍存在显著的细胞大小均一性，在特定场景下这一特性是生理功能的必需条件。本研究将动力学破碎理论（kinetic fragmentation）应用于组织发育与稳态维持过程，以探究细胞大小分布的时间演化规律。我们的理论预测细胞大小将呈现自相似概率密度函数（PDF），并阐释了细胞分裂时长与空间重分配机制如何保障整个组织内的细胞大小均一性。对汇合态非稳态组织培养物的理论预测与数值模拟结果表明，细胞大小分布确实具有自相似性。我们的实验数据验证了上述预测，同时证实正如理论假设的那样，细胞分裂时长与细胞大小呈幂律缩放关系。研究发现在稳态条件下，细胞大小分布存在带有对数正态拖尾的稳态分布，这与我们的实验数据高度一致。我们的理论预测与数值模拟结果还显示，概率密度函数的形态取决于凋亡细胞所腾出空间的重分配方式，且凋亡细胞的发生率可能也与细胞大小相关。