ARTS mediates apoptosis and regeneration of the intestinal stem cell niche.

Koren, Elle; Yosefzon, Yahav; Ankawa, Roi; Soteriou, Despina; Jacob, Avi; Nevelsky, Alexander; Ben-Yosef, Rahamim; Bar-Sela, Gil et al. · Nat Commun · 2018

basic_science · Level V

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Abstract

Stem cells (SCs) play a pivotal role in fueling homeostasis and regeneration. While much focus has been given to self-renewal and differentiation pathways regulating SC fate, little is known regarding the specific mechanisms utilized for their elimination. Here, we report that the pro-apoptotic protein ARTS (a Septin4 isoform) is highly expressed in cells comprising the intestinal SC niche and that its deletion protects Lgr5<sup>+</sup> and Paneth cells from undergoing apoptotic cell death. As a result, the Sept4/ARTS<sup>-/-</sup> crypt displays augmented proliferation and, in culture, generates massive cystic-like organoids due to enhanced Wnt/β-catenin signaling. Importantly, Sept4/ARTS<sup>-/-</sup> mice exhibit resistance against intestinal damage in a manner dependent upon Lgr5<sup>+</sup> SCs. Finally, we show that ARTS interacts with XIAP in intestinal crypt cells and that deletion of XIAP can abrogate Sept4/ARTS<sup>-/-</sup>-dependent phenotypes. Our results indicate that intestinal SCs utilize specific apoptotic proteins for their elimination, representing a unique target for regenerative medicine.

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