Jichu yixue yu linchuang (Aug 2022)

Gut epithelial Depdc5/mTORC1 signaling axis regulates mouse intestinal epithelial homeostasis

  • ZHANG Xin-ge, MA Jie, WANG Qing-zhi, XIN Yue, YANG Chen-yan, XIONG Xi-wen

DOI
https://doi.org/10.16352/j.issn.1001-6325.2022.08.1213
Journal volume & issue
Vol. 42, no. 8
pp. 1213 – 1219

Abstract

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Objective To investigate the effect of over-activation of mTORC1 on mouse intestinal epithelial homeostasis by conditional knockout of Depdc5. Methods Mice were divided into Depdc5flox/flox group (control group), Depdc5flox/flox:Villin-Cre group (IKO group), rapamycin-Depdc5flox/flox group (rap-Ctrl group) rapamycin-Depdc5flox/flox:Villin-Cre group (rap-IKO group). Western blot was used to detect the protein expression of DEPDC5 and the phosphorylation S6 (PS6) which is the downstream molecule of mTORC1 in the intestinal epithelium. qPCR was applied to detect the mRNA levels of Dclk1, Trpm5 and Muc2 in intestinal epithelial cells (IECs). Hematoxylin-eosin (HE) staining was used to observe the intestinal morphology changes. Immunohistochemical (IHC) staining and alcian blue staining were used to detect the number of tuft cells, Paneth cells, proliferative cells and goblet cells. Results The protein expression of PS6 in the small intestine and colon from the mice of IKO group was obviously up-regulated than that of the control group (0.957±0.028 vs. 0.598±0.041) (P＜0.05). The mRNA levels of Dclk1, Trpm5, and Muc2 were significantly decreased in the IKO group than those in the control group (P＜0.05). The numbers of tuft cells, Paneth cells and goblet cells in the IKO group were all significantly reduced than that in the control group. Nevertheless, the crypt depth in the IKO group was significantly higher than that of the control group (P＜0.05), and the number of proliferative cells was also increased in the IKO group(P＜0.05). Conclusions The over-activation of mTORC1 inhibits the differentiation of IECs and impairs the homeostasis of intestinal epithelial.

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