Elsevier

Molecular Metabolism

Volume 6, Issue 10, October 2017, Pages 1296-1303
Molecular Metabolism

Brief Communication
Single-cell RNA-sequencing reveals a distinct population of proglucagon-expressing cells specific to the mouse upper small intestine

https://doi.org/10.1016/j.molmet.2017.07.014Get rights and content
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Highlights

  • Single cell RNAseq divides upper small intestinal PPG-cells into 3 major clusters.

  • PPG-cell clusters exhibit distinct expression profiles for hormones and receptors.

  • PPG-cells produce a variety of hormones detectable by mass spectrometry.

  • A new mouse PPG-cell cluster expresses the markers Tph1 and Pzp.

Abstract

Objectives

To identify sub-populations of intestinal preproglucagon-expressing (PPG) cells producing Glucagon-like Peptide-1, and their associated expression profiles of sensory receptors, thereby enabling the discovery of therapeutic strategies that target these cell populations for the treatment of diabetes and obesity.

Methods

We performed single cell RNA sequencing of PPG-cells purified by flow cytometry from the upper small intestine of 3 GLU-Venus mice. Cells from 2 mice were sequenced at low depth, and from the third mouse at high depth. High quality sequencing data from 234 PPG-cells were used to identify clusters by tSNE analysis. qPCR was performed to compare the longitudinal and crypt/villus locations of cluster-specific genes. Immunofluorescence and mass spectrometry were used to confirm protein expression.

Results

PPG-cells formed 3 major clusters: a group with typical characteristics of classical L-cells, including high expression of Gcg and Pyy (comprising 51% of all PPG-cells); a cell type overlapping with Gip-expressing K-cells (14%); and a unique cluster expressing Tph1 and Pzp that was predominantly located in proximal small intestine villi and co-produced 5-HT (35%). Expression of G-protein coupled receptors differed between clusters, suggesting the cell types are differentially regulated and would be differentially targetable.

Conclusions

Our findings support the emerging concept that many enteroendocrine cell populations are highly overlapping, with individual cells producing a range of peptides previously assigned to distinct cell types. Different receptor expression profiles across the clusters highlight potential drug targets to increase gut hormone secretion for the treatment of diabetes and obesity.

Keywords

Single cell RNA seq
GLP-1
PPG-cells
L-cells
Mass spectrometry
5-HT

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