Single-cell sequencing of enteroendocrine cells (EEs) in Drosophila midgut.

Enteroendocrine cells (EEs) in the intestinal epithelium have important endocrine functions, yet this cell lineage exhibits great local and regional variations that have hampered detailed characterization of EE subtypes. Through single cell RNA-sequencing analysis, combined with a collection of neuropeptide/receptor knock-in strains, here we provide a comprehensive analysis of cellular diversity, spatial distribution and transcription factor (TF) code of EEs in adult Drosophila midgut. We identify 10 major EE subtypes that totally produced 14 different classes of hormone peptides. Each EE on average co-produces 2-5 different classes of hormone peptides. Functional screen with subtype-enriched TFs suggests a combinatorial TF code that controls EE cell diversity, with class-specific TFs Mirr and Ptx1that respectively define two major classes of EEs, and regional TFs such as Esg, Drm, Exex and Fer1that further define regional EE identity. Our single-cell data should greatly facilitate Drosophila modeling of EE differentiation and function. Overall design: FACS sort EE cells using CG32547-KI-GAL4> uas-GFP line and perform 10X genomics single cell sequencing. Raw data was further processed by Seurat algorithm and EE subtypes were visualized by generating a t-distributed stochastic neighborhood embedding (t-SNE) plot.