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。在胚胎发育、组织再生与稳态维持过程中，细胞增殖必须接受空间信号的协同调控，才能使细胞获得正确的尺寸与形态。生物组织还具备显著的细胞大小均一性，在特定场景下这一特性属于生理需求。本研究将动力学碎裂理论（kinetic fragmentation theory）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。我们的理论预测了细胞大小的自相似概率密度函数（PDF），并阐释了细胞分裂时间与空间重分配如何确保整个组织内的细胞大小均一性。针对汇合态非稳态组织培养物的理论预测与数值模拟结果显示，细胞大小分布具有自相似性。我们的实验数据验证了上述预测，同时证实如理论所假设的那样，细胞分裂时间与细胞大小呈幂律缩放关系。研究发现，在稳态维持条件下存在带有对数正态尾部的稳态分布，这与我们的实验数据相符。我们的理论预测与数值模拟结果还表明，概率密度函数的形态取决于凋亡细胞所遗留空间的重分配方式，且细胞凋亡率可能也与细胞大小相关。