Why did we fund this fellowship?
This award aims to replace rodents in some pancreatitis and pancreatic cancer studies by using in situ transcriptomics to inform pancreatic organoid method development.
The pancreas consists of an endocrine system, which controls blood glucose levels, and an exocrine system, which secretes enzymes that control digestion. Disease in the pancreatic exocrine system is associated with high mortality and research is ongoing to develop therapeutic strategies. Mice are the most common animal model used to study pancreatic disease, with pancreatitis induced via injections of caerulein resulting in elevated enzyme levels, inflammation and cellular death. Pancreatic cancer is associated with similar high mortality rates and research on disease pathogenesis includes the use of genetically altered (GA) animals and xenograft models. Developing GA models can require extensive breeding programmes to generate the multiple mutations involved in disease. Animal models of pancreatitis and pancreatic cancer are associated with significant suffering. In vitro systems such as pancreatic organoids exist but these currently do not fully recapitulate the complexity of the pancreas as they have limited exocrine differentiation and structural organisation, preventing their use as an alternative to animal models.
In this Fellowship, Dr Jean-Francois Darrigand will develop a synthetic microenvironment to promote exocrine differentiation in pancreatic organoids. He will use in situ transcriptomics to define biochemical cues in the embryonic pancreas microenvironment and replicate this in vitro by introducing the cues to organoids cultured in a 3D microarray platform. The microcavities this platform is based on are commercially available and enable high-throughput imaging using confocal microscopes. Jean-Francois will then replicate pancreatitis and pancreatic cancer, using caerulein and genetically modified stem cells, and compare the pathophysiological features to animal models to validate the organoids. Jean-Francois will develop skills in cell culture, fluorescent imaging and RNA-based sequencing techniques.
The pancreas consists of two organs in one. The endocrine part houses insulin-secreting cells controlling blood glucose levels and the exocrine part produces enzymes controlling the digestion. Diseases affecting the exocrine pancreas, such as pancreatitis and pancreatic cancer, present dramatic mortality rates, as highlighted by the 95% mortality of patients diagnosed with pancreatic cancer. To alleviate the societal burden caused by these diseases, research teams all over the world are trying to better understand pancreatic diseases and establish early diagnosis and innovative therapeutic strategies. To develop and test the efficacy of these strategies, genetically engineered mouse models replicating most human pathophysiological features are routinely used in research labs. Although necessary for research purposes, the use of these models leads to the culling of thousands of animals worldwide every year.
Organoids are emerging 3D in vitro systems derived from stem cells, which represent a very promising alternative to animal models. Organoids are simplified versions of organs, of which they should recapitulate the physiology and microanatomy. Unfortunately, the pancreatic organoids generated so far do not faithfully recapitulate the pancreas complexity. This strongly limits the adoption of pancreas organoids as valuable replacement models in the labs working on pancreatic diseases. The goal of this project is thus to develop physiologically relevant organoid models for studying pancreatitis and pancreatic cancer in vitro. The formation of the pancreas in the embryo is known to be tightly regulated by its local microenvironment, whose precise composition is still poorly known.
The first goal of the project is to define the pancreas microenvironment observed in embryos and to reproduce it artificially in vitro for the maturation of organoids. To that end, I will use cutting-edge sequencing technologies on mouse embryonic pancreas and precisely define the biochemical cues that compose its microenvironment. I will then use the identified cues to supplement artificial microcavities in which organoids will be cultured. Cultured organoids will be monitored for the acquisition of mature morphological and physiologic pancreatic markers. This approach will allow me to identify the best microcavities composition to mature pancreatic organoids. To model pancreatitis, organoids will be treated with caerulein, a drug used to induce pancreatitis in animal models. To model pancreatic cancer, I will generate organoids using genetically modified stem-cells that over-activate a variant of a gene known to induce pancreatic cancer in mice and humans. I will assess whether the obtained organoids are valuable models to study pancreatitis and pancreatic cancer by comparing their pathophysiological features with those observed in animal models. The completion of this project will surely enable a significant reduction of animal procedures and provide research labs with new tools to screen the effect of next-generation drugs for pancreatic diseases treatment.