Invisible cues – Mechanobiology in organoids

To gain a complete understanding of cellular behavior, whether healthy or aberrant, we need to understand how cells respond to their environment. Mechanical cues are an integral part of this environment, yet their effect on cells has been difficult to study. Existing techniques to apply and measure mechanical stimuli in a controlled manner are largely limited to either individual cells, or two-dimensional (2D) sheets of cells, precluding the investigation of forces in an in vivo-like setting, where extracellular matrix (ECM) and cells are situated in three-dimensions (3D) and subjected to dynamic forces that depend on this 3D configuration. Moreover, cells are complex systems. To fully understand them, we need to move beyond studies that approach cells as viscoelastic pockets of salty water and embrace the multidisciplinary nature of mechanobiology. We can do this by leveraging the full suite of next-generation tools available in the field of molecular biology and combine those with mechanical perturbations and measurements. It is these two challenges that this thesis aims to make a contribution to: 1) moving mechanobiology towards three dimensions, and 2) integrating biophysics with molecular biology.
More specifically, chapter 2 described the development and optimization of a novel uniaxial stretching device, that through the use of ECM droplets, can apply strain to organoids. Then, chapter 3 described how we used this device to strain intestinal organoids and how we applied single-cell RNA sequencing to discover that the process of enterocyte maturation is directed by strain. Finally, chapter 4 described the development and characterization of a novel organoid model: human trunk- like structures (hTLS), which mimic early human spine and spinal cord co-development.