Optogenetic control of force transmission in pluripotent epithelia
(English) Development requires a combination of three phenomena: increasing the number of cells, specifying their fates and undergoing morphogenesis, which means acquiring the correct shapes. Apical constriction is an important driving mechanism of morphogenesis, occurring within a cell but bridging...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2026 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/457066 |
| Acceso en línea: | https://hdl.handle.net/2117/457066 https://dx.doi.org/10.5821/dissertation-2117-457066 |
| Access Level: | acceso abierto |
| Palabra clave: | mechanobiology pluripotent stem cells morphogenesis epithelial tissue optogenetics ptogenetics apical constriction stem cells epithelial jamming traction force microscopy 51 - Matemàtiques 576 - Biologia cel·lular i subcel·lular. Citologia Àrees temàtiques de la UPC::Matemàtiques i estadística Àrees temàtiques de la UPC::Enginyeria biomèdica |
| Sumario: | (English) Development requires a combination of three phenomena: increasing the number of cells, specifying their fates and undergoing morphogenesis, which means acquiring the correct shapes. Apical constriction is an important driving mechanism of morphogenesis, occurring within a cell but bridging with tissular scale to acquire and maintain shape. Apical constriction is well studied at the cellular level and conserved through the animal kingdom, but the forces that need to be generated and transmitted through the tissue in the process have never been measured and described. To fill this gap, we used a novel optogenetic tool to induce apical constriction in human pluripotent stem cells, combined with traction force microscopy to measure the mechanical forces involved in the process. With this techniques, we discovered that constriction creates a consistent but small signature in traction maps, compatible with apical contractility increase and volume conservation. In addition, we subjected regions of a monolayer to apical constriction and revealed that the cellular displacement field obeys a screened Poisson equation in two dimensions, which implies the existence of a lengthscale with a rheological origin and allows to obtain the Green's function of the tissue. While deformations can be tailored in space and time, we also find that jamming transitions cannot be engineered through apical contractility, which exposes a strong unjammed nature of this pluripotent epithelium. These insights reveal key rheological aspects of human pluripotent stem cells at timescales relevant for morphogenesis, inaccessible through other techniques. Because this cells are used around the globe to derive organoids and embryo models but are highly understudied mechanically, this work establishes a key building block for future works that require shape or force control in stem cell-derived tissues. |
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