Category: DigeST

Background & aims: Recent evidence has suggested that the intact intestinal epithelial barrier protects our body from a range of immune-mediated diseases. The epithelial layer has an impressive ability to reconstitute and repair upon damage and this process of repair increasingly is seen as a therapeutic target. In vitro models to study this process in primary intestinal cells are lacking.

Methods: We established and characterized an in vitro model of intestinal damage and repair by applying γ-radiation on small-intestinal organoids. We then used this model to identify novel regulators of intestinal regeneration.

Results: We identified hepatocyte nuclear factor 4α (HNF4α) as a pivotal upstream regulator of the intestinal regenerative response. Organoids lacking Hnf4a were not able to propagate in vitro. Importantly, intestinal Hnf4a knock-out mice showed impaired regeneration after whole-body irradiation, confirming intestinal organoids as a valuable alternative to in vivo studies.

Conclusions: In conclusion, we established and validated an in vitro damage-repair model and identified HNF4α as a crucial regulator of intestinal regeneration. Transcript profiling: GSE141515 and GSE141518.

Keywords: Irradiation; Organoids; Regeneration.

Authors

Paula S Montenegro-Miranda, Jonathan H M van der Meer, Christine Jones, Sander Meisner, Jacqueline L M Vermeulen, Jan Koster, Manon E Wildenberg, Jarom Heijmans, Francois Boudreau, Agnes Ribeiro, Gijs R van den Brink, Vanesa Muncan

Link

https://doi.org/10.1016/j.jcmgh.2020.02.007

Background & Aims

Activation factor-1 transcription factor family members activating transcription factors 2 and 7 (ATF2 and ATF7) have highly redundant functions owing to highly homologous DNA binding sites. Their role in intestinal epithelial homeostasis and repair is unknown. Here, we assessed the role of these proteins in these conditions in an intestine-specific mouse model.

Methods

We performed in vivo and ex vivo experiments using Villin-Cre^ERT2Atf2^fl/flAtf7^ko/ko mice. We investigated the effects of intestinal epithelium-specific deletion of the Atf2 DNA binding region in Atf7^-/- mice on cellular proliferation, differentiation, apoptosis, and epithelial barrier function under homeostatic conditions. Subsequently, we exposed mice to 2% dextran sulfate sodium (DSS) for 7 days and 12 Gy whole-body irradiation and assessed the response to epithelial damage.

Results

Activating phosphorylation of ATF2 and ATF7 was detected mainly in the crypts of the small intestine and the lower crypt region of the colonic epithelium. Under homeostatic conditions, no major phenotypic changes were detectable in the intestine of ATF mutant mice. However, on DSS exposure or whole-body irradiation, the intestinal epithelium showed a clearly impaired regenerative response. Mutant mice developed severe ulceration and inflammation associated with increased epithelial apoptosis on DSS exposure and were less able to regenerate colonic crypts on irradiation. In vitro, organoids derived from double-mutant epithelium had a growth disadvantage compared with wild-type organoids, impaired wound healing capacity in scratch assay, and increased sensitivity to tumor necrosis factor-α–induced damage.

Conclusions

ATF2 and ATF7 are dispensable for epithelial homeostasis, but are required to maintain epithelial regenerative capacity and protect against cell death during intestinal epithelial damage and repair.

Authors

Bartolomeus J. Meijer, Francesca P. Giugliano, Bart Baan, Jonathan H.M. van der Meer, Sander Meisner, Manon van Roest, Pim K. Koelink, Ruben J. de Boer, Nic Jones, Wolfgang Breitwieser, Nicole N. van der Wel, Manon E. Wildenberg, Gijs R. van den Brink, Jarom Heijmans, and Vanesa Muncan

Link

https://doi.org/10.1016/j.jcmgh.2020.01.005

During the suckling-to-weaning transition, the intestinal epithelium matures, allowing digestion of solid food. Transplantation experiments with rodent fetal epithelium into subcutaneous tissue of adult animals suggest that this transition is intrinsically programmed and occurs in the absence of dietary or hormonal signals. Here, we show that organoids derived from mouse primary fetal intestinal epithelial cells express markers of late fetal and neonatal development. In a stable culture medium, these fetal epithelium-derived organoids lose all markers of neonatal epithelium and start expressing hallmarks of adult epithelium in a time frame that mirrors epithelial maturation in vivo In vitro postnatal development of the fetal-derived organoids accelerates by dexamethasone, a drug used to accelerate intestinal maturation in vivo Together, our data show that organoids derived from fetal epithelium undergo suckling-to-weaning transition, that the speed of maturation can be modulated, and that fetal organoids can be used to model the molecular mechanisms of postnatal epithelial maturation.

Authors

Marit Navis, Tania Martins Garcia, Ingrid B Renes, Jacqueline Lm Vermeulen, Sander Meisner, Manon E Wildenberg, GIjs R van den Brink, Ruurd M van Elburg, Vanesa Muncan

Link

https://doi.org/10.15252/embr.201846221

In many mammalian species, the intestinal epithelium undergoes major changes that allow a dietary transition from mother’s milk to the adult diet at the end of the suckling period. These complex developmental changes are the result of a genetic programme intrinsic to the gut tube, but its regulators have not been identified. Here we show that transcriptional repressor B lymphocyte-induced maturation protein 1 (Blimp1) is highly expressed in the developing and postnatal intestinal epithelium until the suckling to weaning transition. Intestine-specific deletion of Blimp1 results in growth retardation and excessive neonatal mortality. Mutant mice lack all of the typical epithelial features of the suckling period and are born with features of an adult-like intestine. We conclude that the suckling to weaning transition is regulated by a single transcriptional repressor that delays epithelial maturation.

Authors

Vanesa Muncan, Jarom Heijmans, Stephen D Krasinski, Nike V Buller, Mano E Wildenberg, Sander Meisner, Marjana Radonjic, Kelly A Stapleton, Wout H Lamers, Izak Biemond, Marius A van den Bergh Weerman, Donal O’Carroll, James C Hardwick, Daniel W Hommes, Gijs R van den Brink

Link

https://doi.org/10.1038/ncomms1463