Characterisation of human pancreatic organoids: navigating towards islets of Langerhans

Abstract

For a small patient group with type 1 diabetes (T1D), standard treatment with insulin is very difficult, and donor pancreas or islet transplantation is an option. Nonetheless, limited donor organs mean that alternative sources for cell-replacement therapy are desirable. We investigated the presence of human adult stem cells (or progenitor cells) in the exocrine part of the pancreas, in the context of the possible application of these cells in cell therapy for T1D. We developed a 3D cell culture method for the generation of min-organs, or 'organoids' of pancreatic tissue, and found that such organoids differentiated into a limited number of insulin-positive cells. Further, we isolated a subpopulation from these cultures with progenitor-cell characteristics, which could differentiate into insulin-positive cells. Thereby, showing that it is possible to isolate an endocrine subpopulation of progenitor cells, and that pancreatic tissue can expand through cultivation of organoids. We also explored, a way to improve culture conditions via retinoic acid (RA) signalling. We found that organoid formation from the precursor cell population was was improved when we blocked signal transduction via RA. In addition, it appeared that RA could somewhat enhance expression of endocrine markers such as insulin in organoids. Finally, looking at the single-cell level, we could determine that pancreatic organoids retained the overall RNA profile of mature exocrine cells. We find that 3D culture of human pancreatic organoids represents a system with interesting potential both for clinical applications such as cell therapy, as well as as a model for fundamental research.