To the point:
54 compounds affecting pancreas development: Using an image-based screen and a robust analysis pipeline, researchers screened hundreds of molecules and identified 54 compounds that change pancreas organoids shape and/or cell types.
Generating functional human pancreatic acinar cells: Researchers focused on the compounds that inhibit the GSK3A/B protein and drive pancreatic progenitor cells to differentiate into pancreatic acinar cells. A further optimization of the growth media enabled the progenitor cells to develop into fully functional acinar cells.
Possibilities for pancreatic cancer research: The ability to generate acinar organoids is valuable for future studies on pancreatic exocrine function and cancer initiation in humans, as acinar cells are thought to be an important cell of origin for pancreatic cancer.
Organoids are three-dimensional miniature models of organs, grown in a dish. They have become a valuable tool for studying human development, organ regeneration, function, and disease progression. Organoids derived from patient tissues or created through cell and genetic engineering allow researchers to investigate how specific proteins or their variants affect these processes.
However, current approaches to studying multiple genes at once have limitations. They don't provide a complete picture of how cells change shape and move around in response to genetic and molecular changes. High-content image-based screens provide a better solution for this, but their implementation and analysis pose difficulties.
Researchers in the group of Anne Grapin-Botton, director at the Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) in Dresden, Germany, and also honorary professor at TU Dresden, along with the MPI-CBG Technology Development Studio, have now developed a system to test many different compounds (molecules) at the same time using pancreatic organoids, consisting of human pancreatic progenitor cells. With high-content image-based screening – a way of taking detailed pictures of the cells in the organoids – and quantitative multivariate analysis to analyze the data from these pictures, the researchers were able to identify changes in the cells.
From sphere to rosette shape
"Through the screening of 538 compounds, we found 54 compounds that had a significant effect on the pancreas progenitor organoids. I especially focused on compounds that affected cell identity as well as the shape of organoids and identified inhibitors of the GSK3A/B protein. When this protein is inhibited, the WNT signaling pathway is activated, leading to the expression of genes found in acinar cells. Though we saw an increase of those genes with the inhibition of GSK3A/B, the cells did not fully differentiate into acinar cells. To achieve our goal to differentiate acinar cells, we optimized the medium in which the cells grow," explains Rashmiparvathi Keshara, the lead author of the study and former doctoral student in the group of Anne Grapin-Botton.
"We observed that removal of the growth factor FGF led to further differentiation of our organoids and formation of rosette-like structures. We were very happy to see this, as the self-organization and formation of these structures is a characteristic of acinar cells in the living organism," says Karolina Kuodyte, another author of the study and a postdoctoral researcher in the Grapin-Botton group.
Functional pancreatic acinar cells
With electron microscopy, the researchers found tiny vesicles inside the cells that are a typical feature of enzyme-producing pancreatic acinar cells. They then tested the functionality of acinar cells, confirming they were indeed producing functional enzymes, such as amylase and trypsin, which are important for digestion.
"Acinar cells are thought to be a main contributor to pancreatic cancer. We are really excited to present a protocol for developing human acinar cells with unprecedented functionality in a human pancreas organoid," says Anne Grapin-Botton, who oversaw the study. "Our simple protocol with very few components to differentiate acinar cells has the potential to advance our understanding of pancreas development and may lead to the discovery of new therapeutic targets for pancreatic cancer." The researchers plan to further assess human pancreatic cancer initiation using their system.
