Utilizing organoids to study general and tissue-specific adult stem cell profiles: Exploiting organoid cultures for basic stem cell research

Abstract

In this thesis we describe our efforts to expand the organoid technology toolbox and to utilize organoid technology for basic stem cell research. Organoid technology allows for culturing primary cells from adult tissues in a 3-dimensional way with the support of extracellular matrix and a specific growth factor cocktail, that allows for stem cell maintenance in culture. Up to date, various adult murine and human tissues can be cultured using this approach including, small intestine, liver and recently also squamous epithelial organs such as the epithelium lining the oral cavity. We have developed a similar culture system for mouse epidermis which we use to study the effect of genetic alterations and to look at cell division. Later on, we use this newly established culture method for mouse epidermis as a stem cell assay to study a specific population of epidermal cells expressing Tnrsf19 (encoding the protein Troy). In combination with lineage tracing experiments in mice we confirm the identity of a specific population in the squamous epithelium of the mouse skin that contributes to long term renewal during homeostasis. Furthermore, we utilize organoids derived from human small intestine, colon, liver, pancreas and stomach to identify novel Wnt target genes, target genes of a signaling pathway that is frequently mutated in cancer. Lastly, we describe how organoids can be utilized to study rare cell types in a culturedish. Together we emphasize the broad spectrum of possibilities that arise with the use of organoid technology for basic stem cell research.