Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Nov 27;115(48):12218-12223.
doi: 10.1073/pnas.1719169115. Epub 2018 Nov 7.

Drosophila intestinal stem and progenitor cells are major sources and regulators of homeostatic niche signals

David P Doupé  1   2 , Owen J Marshall  3   4   5 , Hannah Dayton  6 , Andrea H Brand  3   4 , Norbert Perrimon  1   7
Affiliations

Drosophila intestinal stem and progenitor cells are major sources and regulators of homeostatic niche signals

David P Doupé et al. Proc Natl Acad Sci U S A. .

Abstract

Epithelial homeostasis requires the precise balance of epithelial stem/progenitor proliferation and differentiation. While many signaling pathways that regulate epithelial stem cells have been identified, it is probable that other regulators remain unidentified. Here, we use gene-expression profiling by targeted DamID to identify the stem/progenitor-specific transcription and signaling factors in the Drosophila midgut. Many signaling pathway components, including ligands of most major pathways, exhibit stem/progenitor-specific expression and have regulatory regions bound by both intrinsic and extrinsic transcription factors. In addition to previously identified stem/progenitor-derived ligands, we show that both the insulin-like factor Ilp6 and TNF ligand eiger are specifically expressed in the stem/progenitors and regulate normal tissue homeostasis. We propose that intestinal stem cells not only integrate multiple signals but also contribute to and regulate the homeostatic signaling microenvironmental niche through the expression of autocrine and paracrine factors.

Keywords: epithelial homeostasis; insulin; microenvironment; niche; stem cells.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
Transcriptome profiling in the midgut by targeted DamID. (A) Schematic of midgut epithelial cell types. ISCs and EBs (green), ECs (red), and EEs (blue). ISCs divide to self-renew and generate differentiated EC and EE progeny via differentiating EB progenitors. (B and C) Example PolII DamID tracks (with unfused Dam control subtracted) for ISC/EB marker escargot and EC marker trypsin genes. (D) Genome-wide gene POLII occupancy in ISC/EBs vs. ECs with known markers highlighted (green for ISC/EB, red for EC). (E) Overlap in expressed genes in ISC/EB (green) vs. ECs (red) at FDR < 0.01.
Fig. 2.
Fig. 2.
Expression of stem/progenitor-specific TFs. (A–D) Maximum projection z-stacks showing expression of conserved TFs in the midgut. Background signal was subtracted using the remove outliers function (Fiji) and brightness/contrast increased for clarity. DAPI (blue), esg-lacZ (red), and TF (green) for: (A) Sox21a-GFP–tagged fosmid, (B) Sox100B-GFP trap, (C) jumu-GFP protein trap, and (D) apt-GFP protein trap. (Scale bars, 20 μm.) (E–G) Quantification of TF reporter overlap with (E) esg-lacZ, (n ≥ 10 guts), (F) Delta-lacZ (n ≥ 9 guts), (G) Su(H)-lacZ (n ≥ 9 guts), and (H) prospero staining (n ≥ 7 guts).
Fig. 3.
Fig. 3.
Function of stem/progenitor-specific TFs. (A–G) Representative projected z-stack images of TF RNAi lineage tracing at 10 d postinduction of labeling. DAPI (blue), GFP lineage marker (green). RNAi line as indicated in each panel. (Scale bars, 20 µm.) (H) Proportion of labeled cells in posterior midgut at 10 d of TF knockdown. At least 12 guts from at least 3 independent replicates were scored for each condition, *P < 0.05, **P < 0.01 in two-tailed Student’s t test.
Fig. 4.
Fig. 4.
Stem/progenitor-specific TF profiling identifies ligands of major pathways. (A) Overlap of genes showing ISC/EB expression (green), EC expression (red), Sox21 binding (blue), and cic binding (gray). See Dataset S4 for gene lists. (B) GO terms enriched in the 631 genes specifically expressed in ISC/EBs and with regulatory regions bound by both Sox21a and cic. (C) Major developmental signaling pathway ligands specifically expressed in ISC/EBs and bound by both Sox21a and cic. (D) Expression of Ilp6 in ISC/EBs. DAPI (blue), EGFP driven by Ilp6-GAL4 (green), and esg-lacZ (red). (Scale bars, 20 µm.) (E) Expression of egr in ISC/EBs. DAPI (blue), egr-GFP protein trap (green), and esg-lacZ (red). (Scale bars, 20 µm.)
Fig. 5.
Fig. 5.
Ilp6 and egr regulate epithelial homeostasis. (A–C) Knockdown of Ilp6 increases tissue turnover. Lineage tracing (GFP, green) shows a significant increase in cell production on Ilp6 knockdown (B) compared with control luciferase RNAi (A) (blue is DAPI, red is EE marker prospero) as quantified in C (n ≥ 17 guts, **P < 0.01 in two tailed Student’s t test). (Scale bars, 20 µm.) (D–H) Overexpression of egr increases epithelial turnover. Overexpression of egr (F) increases cell production compared with control RNAi (D) and Ilp6 overexpression (E), quantification in G (n ≥ 15 guts, *P < 0.05, **P < 0.01 in two tailed Student’s t test). EE cell production is reduced on Ilp6 overexpression (E) and increased on egr overexpression (F) as quantified in H (n ≥ 15 guts, **P < 0.01 in two tailed Student’s’ t test). (Colors and scale bars as in A and B.) (I, K, and L) egr overexpression affects the expression of a puc-lacZ reporter (red), particularly inducing expression in GFP+ cells (white arrowheads). DAPI is blue, GFP driven by esg-GAL4 is green. (Scale bar: 20 µm.) (J) egr overexpression increases whole-gut expression of cytokine ligand upd3 by qPCR. *P < 0.05. (M) Schematic of known ISC/EB-derived signals (for references, see main text) showing ISCs (dark green), EBs (light green), ECs (red), and visceral muscle (VM, orange). Arrows indicate known (solid lines) or proposed (dashed lines) target cell types.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Micchelli CA, Perrimon N. Evidence that stem cells reside in the adult Drosophila midgut epithelium. Nature. 2006;439:475–479. - PubMed
    1. Ohlstein B, Spradling A. The adult Drosophila posterior midgut is maintained by pluripotent stem cells. Nature. 2006;439:470–474. - PubMed
    1. de Navascués J, et al. Drosophila midgut homeostasis involves neutral competition between symmetrically dividing intestinal stem cells. EMBO J. 2012;31:2473–2485. - PMC - PubMed
    1. Doupé DP, Jones PH. Cycling progenitors maintain epithelia while diverse cell types contribute to repair. BioEssays. 2013;35:443–451. - PubMed
    1. Guo Z, Lucchetta E, Rafel N, Ohlstein B. Maintenance of the adult Drosophila intestine: All roads lead to homeostasis. Curr Opin Genet Dev. 2016;40:81–86. - PMC - PubMed

Publication types

Substances