14 March 2017
Parsing the Pancreas
In this commentary, published in New England Journal of Medicine, DanStem professors Anne Grapin-Botton and Palle Serup cover recent results obtained with new single-cell RNA-Seq measurements of mouse and human pancreas cells.
The most widely used single-cell transcriptomics assay, adapted from an assay that analyzes cell populations, is RNA-seq (RNA sequencing); RNA-seq measures global gene expression by reverse transcribing RNA into complementary DNA and then sequencing it. This strategy has been used to compare gene expression between samples, for example between a tissue from a diseased patient or a healthy individual. However, if different cells have different gene expression changes, this is not seen with such a strategy.In the single-cell RNA-seq protocol, individual cells are typically captured in microfluidic devices or by means of flow cytometry. This strategy uncovers changes between different cells from an organ and can compare them individually to the cell profiles of a diseased organ.
Analyses of single-cell RNA-seq data are substantially more challenging than analyses of data from similar experiments on cell populations, which have been facilitated by the development of analysis and quality-control pipelines that make use of customized computer algorithms. Notably, as described in four recent papers, this technique has been used to analyze large numbers of single cells from human islet preparations, which by their very nature contain lots of contaminating non-islet cells, allowing a sampling of all pancreatic cell types. These analyses identified all the known cell types, including rare cells such as the ghrelin-producing epsilon-cell. In addition, new subgroups among beta cells and duct cells were identified. “Importantly, the profile of some cells was found to change in type 2 diabetes patients and these could prove important for future disease studies”, says Palle Serup.
Grapin-Botton, Anne & Palle Serup (2017). Parsing the Pancreas. The New England Journal of Medicine, 376(9), 886-888, doi:10.1056/NEJMcibr1616217