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Transient and heterogeneous YAP1 activity drives self-organization in intestinal organoid development

Mayr, Urs. Transient and heterogeneous YAP1 activity drives self-organization in intestinal organoid development. 2019, Doctoral Thesis, University of Basel, Faculty of Science.

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Official URL: http://edoc.unibas.ch/diss/DissB_13524

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Abstract

Recent years have seen an explosion in the ability to grow organoids which phenocopy diverse organs ranging from intestinal epithelium to complex cerebral structures. All organoid models emerge from the potential of individual cells to self-organize into higher order structures under homogenous conditions. They can be established by extracting adult stem cells from healthy or diseased tissue or by directed differentiation of pluripotent stem cells. Protocols have been established to culture them in well-defined conditions and use them for any standard biological or molecular technology. In addition, they are more amenable to imaging approaches, allowing researchers to gain access to early development processes. Despite the exciting promises of organoid technologies and the hope that they will result in new human therapies, little is known about self-organization into complex organ like structures. This type of basic knowledge about the underlying process is required for applied breakthrough to occur.
In this work, we used the enormous regenerative capacity of the small intestine to study how cells with stem and non-stem cell identity self-organize into organoids. A quantitative study identified a YAP1 driven transient dedifferentiation, occurring independently of the starting population, into proliferative, homogenous cysts able to reconstitutes all cell types of the mature tissue. In contrast to the prevalent view of organoid development, this intermediate state exhibits not intestinal stem cell but fetal-like characteristics. By addressing how asymmetries emerge within homogenous cysts to specify Paneth cells, the first symmetry breaking event in this system, we identified large degrees of cell-to-cell variability in YAP1 activity preceding symmetry breaking. This YAP1 cell-to-cell variability in its subcellular localization is essential to drive a Notch-Delta lateral inhibition event that specifies Paneth cell fate.
In conclusion, this works shows how combining live and 4i multiplexed imaging, sequencing and perturbation approaches can bridge decision making at the single cell level, by lateral-inhibition driven cell-fate decision, to different phenotypic outcomes on the tissue level, the occurrence of budding organoids or because of failed symmetry breaking, enterocsyts. This study gives a first glance into the complex interaction networks endowing individual cells with the capacity to self-organize into organoids.
Advisors:Liberali, Prisca and Gasser, Susan M. and Gilmour, Darren
Faculties and Departments:09 Associated Institutions > Friedrich Miescher Institut FMI > Quantitative Biology > Cellular heterogeneity during collective cell behavior (Liberali)
Item Type:Thesis
Thesis Subtype:Doctoral Thesis
Thesis no:13524
Thesis status:Complete
Bibsysno:Link to catalogue
Number of Pages:1 Online-Ressource (IV, 105 Seiten)
Language:English
Identification Number:
Last Modified:24 Feb 2020 15:03
Deposited On:24 Feb 2020 15:02

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