Using single-cell multi-omics screening of human fetal pancreas to identify novel players in human beta cell development

Abstract

Islet transplantation from organ donors can considerably improve glucose homeostasis and well-being in individuals with type 1 diabetes, where the beta cells are destroyed by the autoimmune attack, but there are insufficient donor islets to make this a widespread therapy. Strategies are therefore being developed to generate unlimited amounts of insulin-producing beta cells from pluripotent stem cells, with the aim that they will be transplanted to treat diabetes. Whilst much progress has been made in recent years in the directed differentiation of pluripotent stem cells to beta-like cells, essential gaps still exist in generating stem cell-derived beta cells that are fully functional in vitro. This short review provides details of recent multi-'omics' studies of the human fetal pancreas, which are revealing granular information on the various cell types in the developing pancreas. It is anticipated that this fine mapping of the pancreatic cells at single-cell resolution will provide additional insights that can be utilised to reproducibly produce human beta cells in vitro that have the functional characteristics of beta cells within native human islets.

Keywords: beta cells; development; gene analysis; human pancreas; stem cells; transcription factors.

FIGURE 1

Genes driving human beta cell development. (a) Chronological line indicating some transcription factors that are important in pancreas and islet development., , , Most of these genes were identified by studying the genetics of pancreatic agenesis or neonatal diabetes. Loss of ZNF808 was recently identified as a cause of pancreatic agenesis. (b) Representative images showing immunostaining for PDX1 (left) and SOX9 (right) in a Carnegie Stage 13 (30–33 dpc) human embryo. Sections were de‐waxed and antigen retrieval was carried out in citric acid followed by incubation overnight with primary antibodies (goat anti‐PDX1, 1:100 and sheep anti‐SOX9, 1:100). Signals were developed with fluorescently tagged secondary antibodies and images were obtained with a Nikon A1 inverted confocal microscope. Co‐localisation of PDX1 and SOX9 indicates the dorsal pancreatic bud at this stage of development. Arrow = dorsal bud, star = duodenum. Scale bar: 20 μm. (c) Violin plot depicting the expression of endocrine progenitor‐enriched genes (pink) from scRNAseq data of human fetal pancreas.

FIGURE 2

Cell–cell interactions within the developing human pancreas. (a) Schematic showing the spatial proximity of the different cell types identified by spatial transcriptomics of the developing human pancreas. (b) Circos plot showing predicted ligand‐receptor pairs from cell–cell connectivity analysis of human fetal pancreatic cells at 12–20 PCW.

FIGURE 3

Single‐cell multi‐omic tools for studying human pancreas development. Schematic showing different single‐cell genomic tools that have been used to study human pancreas development and the information derived from them.