1. Atg14 protects the intestinal epithelium from TNF-triggered villus atrophy.
- Author
-
Jung H, Leal-Ekman JS, Lu Q, and Stappenbeck TS
- Subjects
- Animals, Apoptosis drug effects, Apoptosis genetics, Atrophy, Autophagy drug effects, Autophagy-Related Proteins genetics, Caspase 3 genetics, Caspase 3 metabolism, Caspase 8 genetics, Caspase 8 metabolism, Cells, Cultured, Intestine, Small drug effects, Intestine, Small growth & development, Intestine, Small pathology, Mice, Mice, Inbred C57BL, Mice, Transgenic, Receptors, Tumor Necrosis Factor, Type I genetics, Tumor Necrosis Factor-alpha pharmacology, Vesicular Transport Proteins genetics, Autophagy genetics, Autophagy-Related Proteins metabolism, Intestinal Mucosa metabolism, Intestinal Mucosa pathology, Intestine, Small metabolism, Microvilli pathology, Receptors, Tumor Necrosis Factor, Type I metabolism, Tumor Necrosis Factor-alpha metabolism, Vesicular Transport Proteins metabolism
- Abstract
Regulation of intestinal epithelial turnover is a key component of villus maintenance in the intestine. The balance of cell turnover can be perturbed by various extrinsic factors including the cytokine TNF, a cell signaling protein that mediates both proliferative and cytotoxic outcomes. Under conditions of infection and damage, defects in autophagy are associated with TNF-mediated cell death and tissue damage in the intestinal epithelium. However, a direct role of autophagy within the context of enterocyte cell death during homeostasis is lacking. Here, we generated mice lacking ATG14 (autophagy related 14) within the intestinal epithelium [ Atg14
f/f Vil1- Cre ( VC )+ ]. These mice developed spontaneous villus loss and intestinal epithelial cell death within the small intestine. Based on marker studies, the increased cell death in these mice was due to apoptosis. Atg14f/f VC+ intestinal epithelial cells demonstrated sensitivity to TNF-triggered apoptosis. Correspondingly, both TNF blocking antibody and genetic deletion of Tnfrsf1a/Tnfr1 rescued villus loss and cell death phenotype in Atg14f/f VC+ mice. Lastly, we identified a similar pattern of spontaneous villus atrophy and cell death when Rb1cc1 / Fip200 was conditionally deleted from the intestinal epithelium ( Rb1cc1f/f VC+ ). Overall, these findings are consistent with the hypothesis that factors that control entry into the autophagy pathway are also required during homeostasis to prevent TNF triggered death in the intestine. Abbreviations: ANOVA: analysis of variance; Atg14 : autophagy related 14; Atg16l1 : autophagy related 16-like 1 (S. cerevisiae); Atg5 : autophagy related 5; cCASP3: cleaved CASP3/caspase-3; cCASP8: cleaved CASP8/caspase-8; CHX: cycloheximide; EdU: 5-ethynyl-2´-deoxyuridine thymidine; f/f: flox/flox; H&E: hematoxylin and eosin; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; Nec-1: necrostatin-1; Rb1cc1/Fip200 : RB1-inducible coiled-coil 1; Ripk1 : receptor (TNFRSF)-interacting serine-threonine kinase 1; Ripk3 : receptor (TNFRSF)-interacting serine-threonine kinase 3; Tnfrsf1a/Tnfr1 : tumor necrosis factor receptor superfamily, member 1a; Tnf/ Tnfsf1a : tumor necrosis factor; VC: Vil1/villin 1 -Cre.- Published
- 2019
- Full Text
- View/download PDF