Figure 4.

Simulated populations of organoids. The model provided by Thalheim et al. [11] enables controlling Wnt and Notch activity in the cells via cell–cell interaction. PCs provide both Wnt and Notch ligands which are necessary for SC maintenance. The number of contacts N required to stabilize the SC fate controls the SC fraction and thus organoid shape and growth velocity. (A) N = 1 after 42 days of culture, (B) N = 2 after 21 days of culture. These differences can be motivated by externally provided growth factors. Colors of the cells as in Figure 1B and Figure 2C. (C) In contrast to the assumptions by Thalheim et al. [11], the growth factors (here Wnt3a) are not homogeneously distributed in the culture [40], potentially resulting in mixtures of the growth types. Small circles: organoids. Figure 4C is published under Creative Commons CC-BY-NC-ND, all rights are reserved by the publisher.