MECHANOIDS · Probing and controlling the three-dimensional organoid mechanobiology

Interaction between cells and their mechanical microenvironment plays a key role in the regulation of development, physiology and disease. Cell behaviour is also regulated by the dimensionality of the microenvironment: 2D cultures displaybiological traits that generally differ from those of 3D tissues, thus limiting their potential in biomedical research. Thislimitation has been addressed by the recent development of Organoids, which faithfully preserve a number of distinctivetissue traits. Still, current biophysical tools and conceptual frameworks are not yet suitable to probe and understand themechanobiology of 3D organoid systems.This project aims to study and manipulate the mechanobiology of normal gut and colorectal cancer organoids. We willdevelop tools to quantify the 3D stresses applied by an organoid embedded in a gel. By measuring its 3D surface stressesand Young’s modulus we will quantify its interstitial pressure and contractility, key parameters in organ growth and tumourprogression.Pressure and contractility will be related with key biological parameters such as geometry, cell adhesion and proliferation.We will fluorescently tag proteins in the organoids that will allow us to track individual cells, as well as monitoring theirpolarization and adhesion. The relationship between mechanics, geometry, and cell function will be further assessed bychemically reducing proliferation, mechanical stresses and adhesion.We will also modify the mechanical state of the organoids through optogenetic means. We will express proteins in the cellsto control Rho-GTPases upon illumination, thereby steering the local stresses at will. We will modify organoid pressure,contractility and geometry and study their influence on the phenotype.As organoids emerge as novel tools in biomedical research, we expect that studying and manipulating their mechanobiologywill bring key insight into disease and development processes, and potential new therapeutic targets.