A step forward

A Step Forward: Optimised organoid culture

The Huch lab at the Gurdon Institute, University of Cambridge, works with liver and pancreas organoids derived from murine and human samples.

The cultures, which were established by Meritxell Huch while at the Clevers lab at the Hubrecht Institute in Utrecht, model in vitro the proliferative response of the ductal population in the adult liver and pancreas (Huch et al, 2013a; Huch et al, 2013b) and represent the first cellular models to be able to expand ex-vivo and long-term tissue from both organs.

Currently, liver organoids can be differentiated in vitro into functional hepatocyte cells using defined growth factor conditions, but this has not yet been achieved with pancreas organoids.

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We aim to identify the mechanism that could facilitate the differentiation of pancreatic organoids into endocrine lineages, to further our understanding of this population of cells, and to potentially serve as platform for a cell therapy for diabetic patients.

Human pancreas organoids are derived from cells of the ductal compartment of the adult human pancreas. To isolate organoids, pancreas samples are digested, enriched for ducts and seeded in a 3D extracellular matrix. Cells in the ducts begin to proliferate, and form cystic organoid structures, enriched for ductal (Krt19, EpCAM) and stem cell/progenitor (Lgr5, Sox9) markers.

A two steps optimisation

In the initial stages of the project, we will focus on optimising the media for long-term expansion of the human pancreas organoids. Starting with published media compositions (Boj et al, 2015) we will optimise our culture system by testing growth factors in the media, and determining whether the human pancreas organoids can be expanded over several passages. Further to this, we will also assess whether the expanded cells retain their genetic stability over long term expansion.

In a second phase of the project, we also aim to optimise media for differentiation of the ductal organoids into endocrine committed cells. Organoids can differentiate into endocrine cells when genetically reprogrammed to express a combination of specific endocrine transcription factors (Lee et al, 2013 and Dorrell et al, 2014). Furthermore mouse organoid cultures have been differentiated by mixing with embryonic pancreas cells and transplanting in vivo under the kidney capsule (Huch et al, 2013b). Our aim is to differentiate human pancreas organoids in vitro using only defined growth factor conditions.

We believe that the strategy proposed holds the potential to facilitate the expansion and differentiation of human pancreas organoids into endocrine-committed lineage cells.

Bibliography

Boj, S. F. et al. Organoid models of human and mouse ductal pancreatic cancer. Cell 160, 324–338 (2015).
Dorrell, C. et al. The organoid-initiating cells in mouse pancreas and liver are phenotypically and functionally similar. Stem Cell Research 13, 275-283 (2014).
Huch, M. et al. In vitro expansion of single Lgr5+ liver stem cells induced by Wnt-driven regeneration. Nature 494, 247–50 (2013).
Huch, M. et al. Unlimited in vitro expansion of adult bi-potent pancreas progenitors through the Lgr5/R-spondin axis. EMBO J. 32, 2708–21 (2013).
Lee, J. et al. Expansion and conversion of human pancreatic ductal cells into insulin-secreting endocrine cells. Elife 2013, 1–22 (2013).

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